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Sample records for molten carbonate anode

  1. Performance and properties of anodes reinforced with metal oxide nanoparticles for molten carbonate fuel cells

    Science.gov (United States)

    Accardo, Grazia; Frattini, Domenico; Yoon, Sung Pil; Ham, Hyung Chul; Nam, Suk Woo

    2017-12-01

    Development of electrode materials for molten carbonate fuel cells is a fundamental issue as a balance between mechanical and electrochemical properties is required due to the particular operating environments of these cells. As concern the anode, a viable strategy is to use nano-reinforced particles during electrodes' fabrication. Candidate nanomaterials comprise, but are not limited to, ZrO2, CeO2, TiO2, Ti, Mg, Al, etc. This work deals with the characterization and test of two different types of hard oxide nanoparticles as reinforce for NiAl-based anodes in molten carbonate fuel cells. Nano ceria and nano zirconia are compared each other and single cell test performances are presented. Compared to literature, the use of hard metal oxide nanoparticles allows good performance and promising perspectives with respect to the use a third alloying metal. However, nano zirconia performed slightly better than nano ceria as polarization and power curves are higher even if nano ceria has the highest mechanical properties. This means that the choice of nanoparticles to obtain improved anodes performance and properties is not trivial and a trade-off between relevant properties plays a key role.

  2. Natural gas anodes for aluminium electrolysis in molten fluorides.

    Science.gov (United States)

    Haarberg, Geir Martin; Khalaghi, Babak; Mokkelbost, Tommy

    2016-08-15

    Industrial primary production of aluminium has been developed and improved over more than 100 years. The molten salt electrolysis process is still suffering from low energy efficiency and considerable emissions of greenhouse gases (CO2 and PFC). A new concept has been suggested where methane is supplied through the anode so that the CO2 emissions may be reduced significantly, the PFC emissions may be eliminated and the energy consumption may decrease significantly. Porous carbon anodes made from different graphite grades were studied in controlled laboratory experiments. The anode potential, the anode carbon consumption and the level of HF gas above the electrolyte were measured during electrolysis. In some cases it was found that the methane oxidation was effectively participating in the anode process.

  3. Carbonate fuel cell anodes

    Science.gov (United States)

    Donado, Rafael A.; Hrdina, Kenneth E.; Remick, Robert J.

    1993-01-01

    A molten alkali metal carbonates fuel cell porous anode of lithium ferrite and a metal or metal alloy of nickel, cobalt, nickel/iron, cobalt/iron, nickel/iron/aluminum, cobalt/iron/aluminum and mixtures thereof wherein the total iron content including ferrite and iron of the composite is about 25 to about 80 percent, based upon the total anode, provided aluminum when present is less than about 5 weight percent of the anode. A process for production of the lithium ferrite containing anode by slipcasting.

  4. Electrorefining of High Carbon Ferromanganese in Molten Salts to Produce Pure Ferromanganese

    Directory of Open Access Journals (Sweden)

    Xiao S. J.

    2017-09-01

    Full Text Available High carbon ferromanganese is used as a starting material to prepare pure ferromanganese by electrorefining in molten salts. High carbon ferromanganese was applied as the anode, molybdenum was the cathode and Ag/AgCl was the reference electrode. The anodic dissolution was investigated by linear polarization in molten NaCl-KCl system. Then potentiostatic electrolysis was carried out to produce pure ferromanganese from high carbon ferromanganese. The cathodic product was determined to be a mixture of manganese and iron by x-ray diffraction (XRD. The content of carbon in the product was analyzed by carbon and sulfur analyzer. The post-electrolysis anode was characterized by scanning electron microscope (SEM. The mechanism of the anode dissolution and the distribution of the main impurity of carbon and silicon after electrolysis were discussed.

  5. Critical survey on electrode aging in molten carbonate fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Kinoshita, K.

    1979-12-01

    To evaluate potential electrodes for molten carbonate fuel cells, we reviewed the literature pertaining to these cells and interviewed investigators working in fuel cell technology. In this critical survey, the effect of three electrode aging processes - corrosion or oxidation, sintering, and poisoning - on these potential fuel-cell electrodes is presented. It is concluded that anodes of stabilized nickel and cathodes of lithium-doped NiO are the most promising electrode materials for molten carbonate fuel cells, but that further research and development of these electrodes are needed. In particular, the effect of contaminants such as H/sub 2/S and HCl on the nickel anode must be investigated, and methods to improve the physical strength and to increase the conductivity of NiO cathodes must be explored. Recommendations are given on areas of applied electrode research that should accelerate the commercialization of the molten carbonate fuel cell. 153 references.

  6. Experimental determination of effective surface area and conductivities in the porous anode of molten carbonate fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Yoshikawa, M.; Boden, A.; Sparr, M.; Lindbergh, G. [Central Research Institute for Electric Power Industry, Kanagawa (Japan)

    2006-07-14

    Stationary polarization curves and electrochemical impedance spectroscopy of a porous nickel anode in a molten carbonate fuel cell were obtained in order to determine the active surface area and conductivities with varying degree of electrolyte filling for two anode feed-gas compositions, one simulating operation with steam reformed natural gas and the other one gasified coal. The active surface area for coal gas is reduced by around 70-80% compared to the standard gas composition in the case of Li/Na carbonate. Moreover, an optimal degree of electrolyte filling was shifted toward higher filling degree in the case of operation with coal gas. In order to evaluate the experimental data a one-dimensional model was used. The reaction rate at the matrix/electrode interface is about five times higher than the average reaction rate in the whole electrode in case of 10% electrolyte filling. This result suggests that the lower limit of the filling degree of the anode should be around 15% in order to avoid non-uniform distribution of the reaction in the electrode. Therefore, in the case of applying Li/Na carbonate in the MCFC, an electrolyte distribution model taking into account the wetting properties of the electrode is required in order to set an optimal electrolyte filling degree in the electrode.

  7. All ceramic structure for molten carbonate fuel cell

    Science.gov (United States)

    Smith, James L.; Kucera, Eugenia H.

    1992-01-01

    An all-ceramic molten carbonate fuel cell having a composition formed of a multivalent metal oxide or oxygenate such as an alkali metal, transition metal oxygenate. The structure includes an anode and cathode separated by an electronically conductive interconnect. The electrodes and interconnect are compositions ceramic materials. Various combinations of ceramic compositions for the anode, cathode and interconnect are disclosed. The fuel cell exhibits stability in the fuel gas and oxidizing environments. It presents reduced sealing and expansion problems in fabrication and has improved long-term corrosion resistance.

  8. Hybrid Direct Carbon Fuel Cell Performance with Anode Current Collector Material

    DEFF Research Database (Denmark)

    Deleebeeck, Lisa; Kammer Hansen, Kent

    2015-01-01

    collectors were studied: Au, Ni, Ag, and Pt. It was shown that the performance of the direct carbon fuel cell (DCFC) is dependent on the current collector materials, Ni and Pt giving the best performance, due to their catalytic activity. Gold is suggested to be the best material as an inert current collector......The influence of the current collector on the performance of a hybrid direct carbon fuel cell (HDCFC), consisting of solid oxide fuel cell (SOFC) with a molten carbonate-carbon slurry in contact with the anode, has been investigated using current-voltage curves. Four different anode current...

  9. The electrolytic deposition of carbon from molten Li2CO3

    International Nuclear Information System (INIS)

    Dimitrov, A.T.

    2003-01-01

    Electrodeposition of carbon on an nickel electrode in molten salt has been investigated with the aid of scanning electron microscopy (SEM) and cyclic voltammetry, using molten LiCl, as a base electrolyte with adding of 1 and 5 % of Li 2 CO 3 . Commercial nickel wire was used as a cathode and graphite crucible as the anode electrode. A cyclic voltammograms for an nickel electrode indicates that the deposition or discharge of carbon at the cathode occurs at potential range of - 0.8 to -1.7 V. Further, SEM observations showed that morphology of the carbon at the cathode is in the form of a fairly hard black deposit. It was found that the quality of the deposit depends by the cathode surface, applied overpotential, content of lithium carbonate and the thickness of the carbon film. (Original)

  10. Operating method of molten carbonate type fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Nakanishi, Tsuneo

    1988-12-06

    Molten carbonate type fuel cell involves a problem of oxidation of anode while the unit is stopped. Although there is a method proposed wherein an inactive gas is supplied to anode during the stoppage, the market-available inactive gas contains a slight amount of oxygen which makes it difficult to prevent the deterioration of the anode. In this invention, at the start and the stop other than the normal operation, a protective gas mixture of an inactive gas with a small amount of hydrogen is supplied to the anode. The inactive gas is a commercial type nitrogen, argon or helium; hydrogen is mixed in amount 0.5 - 2.0% of the inactive gas. By this method, oxygen in air which comes in from the gas-sealed portion of the cell is reduced by hydrogen in the protective gas and is discharged in the form of water. 2 figs.

  11. Enhancing hybrid direct carbon fuel cell anode performance using Ag2O

    DEFF Research Database (Denmark)

    Deleebeeck, Lisa; Ippolito, Davide; Kammer Hansen, Kent

    2015-01-01

    A hybrid-direct carbon fuel cell (HDCFC), consisting of a molten slurry of solid carbon black and (Li-K)2CO3 added to the anode chamber of a solid oxide fuel cell, was characterized using current-potential-power density curves, electrochemical impedance spectroscopy, and cyclic voltammetry. Two...... types of experimental setups were employed in this study, an anode-supported full cell configuration (two electrodes, two atmospheres setup) and a 3-electrode electrolyte-supported half-cell setup (single atmosphere). Anode processes with and without catalysts were investigated as a function...... of temperature (700-800 °C) and anode sweep gas (N2, 4-100% CO2 in N2-CO2). It was shown that the addition of silver based catalysts (Ag, Ag2O, Ag2CO3) into the carbon-carbonate slurry enhanced the performance of the HDCFC....

  12. Development of molten-carbonate fuel-cell technology. Final report, February-December 1980

    Energy Technology Data Exchange (ETDEWEB)

    1980-01-01

    The objective of the work was to focus on the basic technology for producing molten carbonate fuel cell (MCFC) components. This included the development and fabrication of stable anode structures, preparation of lithiated nickel oxide cathodes, synthesis and characterization of a high surface area (gamma-lithium-aluminate) electrolyte support, pressurized cell testing and modeling of the overall electrolyte distribution within a cell to aid performance optimization of the different cell components. The electrode development program is highlighted by two successful 5000 hour bench-scale tests using stabilized anode structures. One of these provided better performance than in any previous state-of-the-art, bench-scale cell (865 mV at 115 mA/cm/sup 2/ under standard conditions). Pressurized testing at 10 atmosphere of a similar stabilized, high surface area, Ni/Co anode structure in a 300 cm/sup 2/ cell showed that the 160 mA/cm/sup 2/ performance goal of 850 mV on low Btu fuel (80% conversion) can be readily met. A study of the H/sub 2/S-effects on molten carbonate fuel cells showed that ERC's Ni/Co anode provided better tolerance than a Ni/Cr anode. Prelithiated nickel oxide plaques were prepared from materials made by a low temperature and a high temperature powder-production process. The methods for fabricating handleable cathodes of various thicknesses were also investigated. In electrolyte matrix development, accelerated out-of-cell and in-cell tests have confirmed the superior stability of ..gamma..-LiAlO/sub 2/.

  13. A Feasibility Study of Steelmaking by Molten Oxide Electrolysis (TRP9956)

    Energy Technology Data Exchange (ETDEWEB)

    Donald R. Sadoway; Gerbrand Ceder

    2009-12-31

    Molten oxide electrolysis (MOE) is an extreme form of molten salt electrolysis, a technology that has been used to produce tonnage metals for over 100 years - aluminum, magnesium, lithium, sodium and the rare earth metals specifically. The use of carbon-free anodes is the distinguishing factor in MOE compared to other molten salt electrolysis techniques. MOE is totally carbon-free and produces no CO or CO2 - only O2 gas at the anode. This project is directed at assessing the technical feasibility of MOE at the bench scale while determining optimum values of MOE operating parameters. An inert anode will be identified and its ability to sustain oxygen evalution will be demonstrated.

  14. Anodic and cathodic reactions in molten calcium chloride

    International Nuclear Information System (INIS)

    Fray, D.J.

    2002-01-01

    Calcium chloride is a very interesting electrolyte in that it is available, virtually free, in high purity form as a waste product from the chemical industry. It has a very large solubility for oxide ions, far greater than many alkali halides and other divalent halides and has the same toxicity as sodium chloride and also a very high solubility in water. Intuitively, on the passage of current, it is expected that calcium would be deposited at the cathode and chlorine would evolve at the anode. However, if calcium oxide is added to the melt, it is possible to deposit calcium and evolve oxygen containing gases at the anode, making the process far less polluting than when chlorine is evolved. This process is discussed in terms of the addition of calcium to molten lead. Furthermore, these reactions can be altered dramatically depending upon the electrode materials and the other ions dissolved in the calcium chloride. As calcium is only deposited at very negative cathodic potentials, there are several interesting cathodic reactions that can occur and these include the decomposition of the carbonate ion and the ionization of oxygen, sulphur, selenium and tellurium. For example, if an oxide is used as the cathode in molten calcium chloride, the favoured reaction is shown to be the ionization of oxygen O + 2e - → O 2- rather than Ca 2+ + 2 e- → Ca. The oxygen ions dissolve in the salt leaving the metal behind, and this leads to the interesting hypothesis that metal oxides can be reduced directly to the metal purely by the use of electrons. Examples are given for the reduction of titanium dioxide, zirconium dioxide, chromium oxide and niobium oxide and by mixing oxide powders together and reducing the mixed compact, alloys and intermetallic compounds are formed. Preliminary calculations indicate that this new process should be much cheaper than conventional metallothermic reduction for these elements. (author)

  15. Physical properties of molten carbonate electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Kojima, T.; Yanagida, M.; Tanimoto, K. [Osaka National Research Institute (Japan)] [and others

    1996-12-31

    Recently many kinds of compositions of molten carbonate electrolyte have been applied to molten carbonate fuel cell in order to avoid the several problems such as corrosion of separator plate and NiO cathode dissolution. Many researchers recognize that the addition of alkaline earth (Ca, Sr, and Ba) carbonate to Li{sub 2}CO{sub 3}-Na{sub 2}CO{sub 3} and Li{sub 2}CO{sub 3}-K{sub 2}CO{sub 3} eutectic electrolytes is effective to avoid these problems. On the other hand, one of the corrosion products, CrO{sub 4}{sup 2-} ion is found to dissolve into electrolyte and accumulated during the long-term MCFC operations. This would affect the performance of MCFC. There, however, are little known data of physical properties of molten carbonate containing alkaline earth carbonates and CrO{sub 4}{sup 2-}. We report the measured and accumulated data for these molten carbonate of electrical conductivity and surface tension to select favorable composition of molten carbonate electrolytes.

  16. Corrosion-electrochemical behavior of zirconium in molten alkali metal carbonates

    Science.gov (United States)

    Nikitina, E. V.

    2016-08-01

    The corrosion and electrochemical characteristics of zirconium during its interaction with molten lithium, sodium, and potassium carbonates containing from 1 to 5 wt % additives to the salt phase are studied in a temperature range of 500-800°C using gravimetry, corrosion potential measurement, and anodic polarization. The substances decreasing the corrosion losses due to the strengthening and thickening of an oxide film (lithium, sodium, potassium hydroxides) are used as passivators. Sodium chloride, fluoride, and sulfate serve as corrosion stimulators (activators).

  17. A carbon in molten carbonate anode model for a direct carbon fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Li Hongjiao; Liu Qinghua [Tianjin Key Laboratory of Catalysis Science and Technology, School of Chemical Engineering, Tianjin University, Weijing Road 92, Tianjin 300072 (China); State Key Laboratory for Chemical Engineering (Tianjin University), School of Chemical Engineering, Tianjin University, Weijing Road 92, Tianjin 300072 (China); Li Yongdan, E-mail: ydli@tju.edu.c [Tianjin Key Laboratory of Catalysis Science and Technology, School of Chemical Engineering, Tianjin University, Weijing Road 92, Tianjin 300072 (China); State Key Laboratory for Chemical Engineering (Tianjin University), School of Chemical Engineering, Tianjin University, Weijing Road 92, Tianjin 300072 (China)

    2010-02-15

    The electrochemical oxidation of carbon at the anode of a direct carbon fuel cell (DCFC) includes charge transfer steps and chemical steps. A microstructural model of carbon particle is built, in which perfect graphene stacks are taken as the basic building blocks of carbon. A modified mechanism taking account of the irreversibility of the process and supposing that the electrochemical oxidation of carbon takes place only at the edges of the graphene sheets is proposed. A Tafel type overall rate equation is deduced along with expressions of exchange current density (j{sub 0}) and activation polarization (eta{sub act}). The performance of carbon black and graphite as the fuel of DCFC is examined. It has been found that j{sub 0} is in the range of 0.10-6.12 mA cm{sup -2} at 923-1123 K and eta{sub act} is in the range of 0.024-0.28 V at 923-1123 K with current density in 10-120 mA cm{sup -2}. Analysis of the j{sub 0}, eta{sub act} values and the product composition reveals that the charge transfer steps as well as the oxygen ion absorption steps are both important for the reaction rate. The activity of the carbon material with respect to atom location is introduced to the open circuit potential difference (OCP) calculation with Nernst equation.

  18. Mechanistic investigation and modelling of anode reaction in the molten carbonate fuel cell; Mechanistische Untersuchung und Modellierung der Anodenreaktion in der Karbonat-Brennstoffzelle

    Energy Technology Data Exchange (ETDEWEB)

    Schuster, Markus Roman

    2011-04-27

    Considering distributed energy generation, molten carbonate fuel cells (MCFCs) have best prospects to fulfil the demands of the highly competing energy market. To establish MCFC technology in the market, various requirements need to be met. These are on the one hand the reduction of the specific costs per kW and the simultaneous increase in efficiency of the MCFCs. On the other hand, an extended lifetime of MCFC stacks in general and especially when biofuels are used is required. Detailed knowledge of electrodes' reaction mechanisms is essential for successful technical improvements or cost reduction measures. In this thesis, the complex anodic reaction mechanism in the molten carbonate fuel cell is studied in detail, with the objective to develop a fundamental understanding of the physical and electrochemical processes taking place at the anode, and to identify the factors influencing the performance of fuel cell stacks. These include a detailed study of the simultaneously performed oxidation reactions of hydrogen and carbon monoxide and its kinetic parameters, the detailed analysis of mass transport, adsorption and charge transfer and the observation of degradation phenomena, which have a declining effect on cell performance and lifetime. In order to gain this knowledge, several testing facilities have been used: anode half-cells and single cells. Electrochemical impedance spectroscopy (EIS) has been applied as analyzing tool for physical and electrochemical phenomena, whose results have been integrated in the development of an equivalent circuit. Linking the elements of the equivalent circuit with physical process parameters has been done by using a numerical model for the MCFC-anode. The impedance measurements of the MCFC anodes result in four characteristic resistances: ohmic resistance, high-frequency resistance, low-frequency resistance and cumulative resistance. The strongly temperature dependent high-frequency resistance is influenced by the electrode

  19. Application of infiltrated LSCM-GDC oxide anode in direct carbon/coal fuel cells.

    Science.gov (United States)

    Yue, Xiangling; Arenillas, Ana; Irvine, John T S

    2016-08-15

    Hybrid direct carbon/coal fuel cells (HDCFCs) utilise an anode based upon a molten carbonate salt with an oxide conducting solid electrolyte for direct carbon/coal conversion. They can be fuelled by a wide range of carbon sources, and offer higher potential chemical to electrical energy conversion efficiency and have the potential to decrease CO2 emissions compared to coal-fired power plants. In this study, the application of (La, Sr)(Cr, Mn)O3 (LSCM) and (Gd, Ce)O2 (GDC) oxide anodes was explored in a HDCFC system running with two different carbon fuels, an organic xerogel and a raw bituminous coal. The electrochemical performance of the HDCFC based on a 1-2 mm thick 8 mol% yttria stabilised zirconia (YSZ) electrolyte and the GDC-LSCM anode fabricated by wet impregnation procedures was characterized and discussed. The infiltrated oxide anode showed a significantly higher performance than the conventional Ni-YSZ anode, without suffering from impurity formation under HDCFC operation conditions. Total polarisation resistance (Rp) reached 0.8-0.9 Ω cm(2) from DCFC with an oxide anode on xerogel and bituminous coal at 750 °C, with open circuit voltage (OCV) values in the range 1.1-1.2 V on both carbon forms. These indicated the potential application of LSCM-GDC oxide anode in HDCFCs. The chemical compatibility of LSCM/GDC with carbon/carbonate investigation revealed the emergence of an A2BO4 type oxide in place of an ABO3 perovskite structure in the LSCM in a reducing environment, due to Li attack as a result of intimate contact between the LSCM and Li2CO3, with GDC being stable under identical conditions. Such reaction between LSCM and Li2CO3 was not observed on a LSCM-YSZ pellet treated with Li-K carbonate in 5% H2/Ar at 700 °C, nor on a GDC-LSCM anode after HDCFC operation. The HDCFC durability tests of GDC-LSCM oxide on a xerogel and on raw bituminous coal were performed under potentiostatic operation at 0.7 V at 750 °C. The degradation mechanisms were

  20. Carbon particle induced foaming of molten sucrose for the preparation of carbon foams

    International Nuclear Information System (INIS)

    Narasimman, R.; Vijayan, Sujith; Prabhakaran, K.

    2014-01-01

    Graphical abstract: - Highlights: • An easy method for the preparation of carbon foam from sucrose is presented. • Wood derived activated carbon particles are used to stabilize the molten sucrose foam. • The carbon foams show relatively good mechanical strength. • The carbon foams show excellent CO 2 adsorption and oil absorption properties. • The process could be scaled up for the preparation of large foam bodies. - Abstract: Activated carbon powder was used as a foaming and foam setting agent for the preparation of carbon foams with a hierarchical pore structure from molten sucrose. The rheological measurements revealed the interruption of intermolecular hydrogen bonding in molten sucrose by the carbon particles. The carbon particles stabilized the bubbles in molten sucrose by adsorbing on the molten sucrose–gas interface. The carbon foams obtained at the activated carbon powder to sucrose weight ratios in the range of 0–0.25 had a compressive strength in the range of 1.35–0.31 MPa. The produced carbon foams adsorb 2.59–3.04 mmol/g of CO 2 at 760 mmHg at 273 K and absorb oil from oil–water mixtures and surfactant stabilized oil-in-water emulsions with very good selectivity and recyclability

  1. Reactions on carbon anodes in aluminium electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Eidet, Trygve

    1997-12-31

    The consumption of carbon anodes and energy in aluminium electrolysis is higher than what is required theoretically. This thesis studies the most important of the reactions that consume anode materials. These reactions are the electrochemical anode reaction and the airburn and carboxy reactions. The first part of the thesis deals with the kinetics and mechanism of the electrochemical anode reaction using electrochemical impedance spectroscopy. The second part deals with air and carboxy reactivity of carbon anodes and studies the effects of inorganic impurities on the reactivity of carbon anodes in the aluminium industry. Special attention is given to sulphur since its effect on the carbon gasification is not well understood. Sulphur is always present in anodes, and it is expected that the sulphur content of available anode cokes will increase in the future. It has also been suggested that sulphur poisons catalyzing impurities in the anodes. Other impurities that were investigated are iron, nickel and vanadium, which are common impurities in anodes which have been reported to catalyze carbon gasification. 88 refs., 92 figs., 24 tabs.

  2. Overview on CO{sub 2} Valorization: Challenge of Molten Carbonates

    Energy Technology Data Exchange (ETDEWEB)

    Chery, Déborah; Lair, Virginie; Cassir, Michel, E-mail: michel.cassir@chimie-paristech.fr [Chimie ParisTech, CNRS, Institut de Recherche de Chimie Paris, PSL Research University, Paris (France)

    2015-10-02

    The capture and utilization of CO{sub 2} is becoming progressively one of the significant challenges in the field of energetic resources. Whatever the energetic device, it is impossible to avoid completely the production of greenhouse gas, even parting from renewable energies. Transforming CO{sub 2} into a valuable fuel, such as alcohols, CO, or even C, could constitute a conceptual revolution in the energetic bouquet offering a huge application domain. Although several routes have been tested for this purpose, on which a general panorama will be given here, molten carbonates are attracting a renewed interest aiming at dissolving and reducing carbon dioxide in such melts. Because of their unique properties, molten carbonates are already used as electrolytes in molten carbonate fuel cells; they can also provoke a breakthrough in a new economy considering CO{sub 2} as an energetic source rather than a waste. Molten carbonates’ science and technology is becoming a strategic field of research for energy and environmental issues. Our aim in this review is to put in evidence the benefits of molten carbonates to valorize CO{sub 2} and to show that it is one of the most interesting routes for such application.

  3. Molten carbonate fuel cell power generation system. Yoyu tansan prime en gata nenryo denchi hatsuden sochi

    Energy Technology Data Exchange (ETDEWEB)

    Uematsu, K; Hatori, S [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)

    1991-11-01

    In an indirect internal reforming type molten carbonate fuel cell, the reforming temperature is limited less than the operating temperature of the fuel cell, as the heat source for reforming is depended on the reaction heat at about 650 {degree} C of the fuel cell. To improve the reforming rate at the low temperature range, it is considered to increase S/C (ratio of steam to carbon), but this scheme will cause such problems as to increase the voltage drop of the anode, to drop the heat recovery ratio on the cogenerator, to increase the capacity of the heat exchanger, etc. In this invention, in the power generating plant of a molten carbonate fuel cell the inert gas is added to the reforming raw gas, and in addition to the above the gas is mixed with steam and led into the reforming chamber of the plant. When the inert gas which is not directly concerned in the reforming reaction is added to, total mol number increases and the reforming reaction is acceralated. Consequently, the reforming rate can be raised, though the reforming temperature is low. 2 figs.

  4. Research on high-temperature compression and creep behavior of porous Cu–Ni–Cr alloy for molten carbonate fuel cell anodes

    Directory of Open Access Journals (Sweden)

    Li W.

    2015-06-01

    Full Text Available The effect of porosity on high temperature compression and creep behavior of porous Cu alloy for the new molten carbonate fuel cell anodes was examined. Optical microscopy and scanning electron microscopy were used to investigate and analyze the details of the microstructure and surface deformation. Compression creep tests were utilized to evaluate the mechanical properties of the alloy at 650 °C. The compression strength, elastic modulus, and yield stress all increased with the decrease in porosity. Under the same creep stress, the materials with higher porosity exhibited inferior creep resistance and higher steadystate creep rate. The creep behavior has been classified in terms of two stages. The first stage relates to grain rearrangement which results from the destruction of large pores by the applied load. In the second stage, small pores are collapsed by a subsequent sintering process under the load. The main deformation mechanism consists in that several deformation bands generate sequentially under the perpendicular loading, and in these deformation bands the pores are deformed by flattering and collapsing sequentially. On the other hand, the shape of a pore has a severe influence on the creep resistance of the material, i.e. every increase of pore size corresponds to a decrease in creep resistance.

  5. Protection of nuclear graphite toward fluoride molten salt by glassy carbon deposit

    International Nuclear Information System (INIS)

    Bernardet, V.; Gomes, S.; Delpeux, S.; Dubois, M.; Guerin, K.; Avignant, D.; Renaudin, G.; Duclaux, L.

    2009-01-01

    Molten salt reactor represents one of the promising future Generation IV nuclear reactors families where the fuel, a liquid molten fluoride salt, is circulating through the graphite reactor core. The interactions between nuclear graphite and fluoride molten salt and also the graphite surface protection were investigated in this paper by powder X-ray diffraction, micro-Raman spectroscopy and scanning electron microscopy coupled with X-ray microanalysis. Nuclear graphite discs were covered by two kinds of protection deposit: a glassy carbon coating and a double coating of pyrolitic carbon/glassy carbon. Different behaviours have been highlighted according to the presence and the nature of the coated protection film. Intercalation of molten salt between the graphite layers did not occur. Nevertheless the molten salt adhered more or less to the surface of the graphite disc, filled more or less the graphite surface porosity and perturbed more or less the graphite stacking order at the disc surface. The behaviour of unprotected graphite was far to be satisfactory after two days of immersion of graphite in molten salt at 500 deg. C. The best protection of the graphite disc surface, with the maximum of inertness towards molten salt, has been obtained with the double coating of pyrolitic carbon/glassy carbon

  6. Highly reversible lead-carbon battery anode with lead grafting on the carbon surface

    KAUST Repository

    Yin, Jian; Lin, Nan; Zhang, Wenli; Lin, Zheqi; Zhang, Ziqing; Wang, Yue; Shi, Jun; Bao, Jinpeng; Lin, Haibo

    2018-01-01

    A novel C/Pb composite has been successfully prepared by electroless plating to reduce the hydrogen evolution and achieve the high reversibility of the anode of lead-carbon battery (LCB). The deposited lead on the surface of C/Pb composite was found to be uniform and adherent to carbon surface. Because lead has been stuck on the surface of C/Pb composite, the embedded structure suppresses the hydrogen evolution of lead-carbon anode and strengthens the connection between carbon additive and sponge lead. Compared with the blank anode, the lead-carbon anode with C/Pb composite displays excellent charge–discharge reversibility, which is attributed to the good connection between carbon additives and lead that has been stuck on the surface of C/Pb composite during the preparation process. The addition of C/Pb composite maintains a solid anode structure with high specific surface area and power volume, and thereby, it plays a significant role in the highly reversible lead-carbon anode.

  7. Highly reversible lead-carbon battery anode with lead grafting on the carbon surface

    KAUST Repository

    Yin, Jian

    2018-03-27

    A novel C/Pb composite has been successfully prepared by electroless plating to reduce the hydrogen evolution and achieve the high reversibility of the anode of lead-carbon battery (LCB). The deposited lead on the surface of C/Pb composite was found to be uniform and adherent to carbon surface. Because lead has been stuck on the surface of C/Pb composite, the embedded structure suppresses the hydrogen evolution of lead-carbon anode and strengthens the connection between carbon additive and sponge lead. Compared with the blank anode, the lead-carbon anode with C/Pb composite displays excellent charge–discharge reversibility, which is attributed to the good connection between carbon additives and lead that has been stuck on the surface of C/Pb composite during the preparation process. The addition of C/Pb composite maintains a solid anode structure with high specific surface area and power volume, and thereby, it plays a significant role in the highly reversible lead-carbon anode.

  8. Complex formation during dissolution of metal oxides in molten alkali carbonates

    DEFF Research Database (Denmark)

    Li, Qingfeng; Borup, Flemming; Petrushina, Irina

    1999-01-01

    Dissolution of metal oxides in molten carbonates relates directly to the stability of materials for electrodes and construction of molten carbonate fuel cells. In the present work the solubilities of PbO, NiO, Fe2O3,and Bi2O3 in molten Li/K carbonates have been measured at 650 degrees C under...... carbon dioxide atmosphere. It is found that the solubilities of NiO and PbO decrease while those of Fe2O3 and Bi2O3 remain approximately constant as the lithium mole fraction increases from 0.43 to 0.62 in the melt. At a fixed composition of the melt, NiO and PbO display both acidic and basic dissolution...

  9. Anode Sheath Switching in a Carbon Nanotube Arc Plasma

    International Nuclear Information System (INIS)

    Fetterman, Abe; Raitses, Yevgeny; Keidar, Michael

    2008-01-01

    The anode ablation rate is investigated as a function of anode diameter for a carbon nanotube arc plasma. It is found that anomalously high ablation occurs for small anode diameters. This result is explained by the formation of a positive anode sheath. The increased ablation rate due to this positive anode sheath could imply greater production rate for carbon nanotubes.

  10. Investigation of residual anode material after electrorefining uranium in molten chloride salt

    Energy Technology Data Exchange (ETDEWEB)

    Rose, M.A., E-mail: marose@anl.gov [Department of Nuclear Engineering, Purdue University, West Lafayette, IN, 47907 (United States); Nuclear Engineering Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Williamson, M.A.; Willit, J. [Nuclear Engineering Division, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2015-12-15

    A buildup of material at uranium anodes during uranium electrorefining in molten chloride salts has been observed. Potentiodynamic testing has been conducted using a three electrode cell, with a uranium working electrode in both LiCl/KCl eutectic and LiCl each containing ∼5 mol% UCl{sub 3}. The anodic current response was observed at 50° intervals between 450 °C and 650 °C in the eutectic salt. These tests revealed a buildup of material at the anode in LiCl/KCl salt, which was sampled at room temperature, and analyzed using ICP-MS, XRD and SEM techniques. Examination of the analytical data, current response curves and published phase diagrams has established that as the uranium anode dissolves, the U{sup 3+} ion concentration in the diffusion layer surrounding the electrode rises precipitously to levels, which may at low temperatures exceed the solubility limit for UCl{sub 3} or in the case of the eutectic salt for K{sub 2}UCl{sub 5}. The reduction in current response observed at low temperature in eutectic salt is eliminated at 650 °C, where K{sub 2}UCl{sub 5} is absent due to its congruent melting and only simple concentration polarization effects are seen. In LiCl similar concentration effects are seen though significantly longer time at applied potential is required to effect a reduction in the current response as compared to the eutectic salt.

  11. Removal of alkaline-earth elements by a carbonate precipitation in a chloride molten salt

    International Nuclear Information System (INIS)

    Yung-Zun Cho; In-Tae Kim; Hee-Chui Yang; Hee-Chui Eun; Hwan-Seo Park; Eung-Ho Kim

    2007-01-01

    Separation of some alkaline-earth chlorides (Sr, Ba) was investigated by using carbonate injection method in LiCl-KCl eutectic and LiCl molten salts. The effects of the injected molar ratio of carbonate([K 2 (or Li 2 )CO 3 /Sr(or Ba)Cl 2 ]) and the temperature(450-750 deg.) on the conversion ratio of the Sr or Ba carbonate were determined. In addition, the form of the Sr and Ba carbonate resulting from the carbonation reaction with carbonates was identified via XRD and SEM-EDS analysis. In these experiments, the carbonate injection method can remove Sr and Ba chlorides effectively over 99% in both LiCl-KCl eutectic and LiCl molten salt conditions. When Sr and Ba were co-presented in the eutectic molten salt, they were carbonated in a form of Ba 0.5 Sr 0.3 CO 3 . And when Sr was present in LiCl molten salt, it was carbonated in the form of SrCO 3 . Carbonation ratio increased with a decreasing temperature and it was more favorable in the case of a K 2 CO 3 injection than that of Li 2 CO 3 . Based on this experiment, it is postulated that carbonate precipitation method has the potential for removing alkali-earth chlorides from LiCl-KCl eutectic and LiCl molten salts. (authors)

  12. Low-Dimensional Network Formation in Molten Sodium Carbonate.

    Science.gov (United States)

    Wilding, Martin C; Wilson, Mark; Alderman, Oliver L G; Benmore, Chris; Weber, J K R; Parise, John B; Tamalonis, Anthony; Skinner, Lawrie

    2016-04-15

    Molten carbonates are highly inviscid liquids characterized by low melting points and high solubility of rare earth elements and volatile molecules. An understanding of the structure and related properties of these intriguing liquids has been limited to date. We report the results of a study of molten sodium carbonate (Na2CO3) which combines high energy X-ray diffraction, containerless techniques and computer simulation to provide insight into the liquid structure. Total structure factors (F(x)(Q)) are collected on the laser-heated carbonate spheres suspended in flowing gases of varying composition in an aerodynamic levitation furnace. The respective partial structure factor contributions to F(x)(Q) are obtained by performing molecular dynamics simulations treating the carbonate anions as flexible entities. The carbonate liquid structure is found to be heavily temperature-dependent. At low temperatures a low-dimensional carbonate chain network forms, at T = 1100 K for example ~55% of the C atoms form part of a chain. The mean chain lengths decrease as temperature is increased and as the chains become shorter the rotation of the carbonate anions becomes more rapid enhancing the diffusion of Na(+) ions.

  13. Carbon dioxide transport in molten calcium carbonate occurs through an oxo-Grotthuss mechanism via a pyrocarbonate anion.

    Science.gov (United States)

    Corradini, Dario; Coudert, François-Xavier; Vuilleumier, Rodolphe

    2016-05-01

    The reactivity, speciation and solvation structure of CO2 in carbonate melts are relevant for both the fate of carbon in deep geological formations and for its electroreduction to CO (to be used as fuel) when solvated in a molten carbonate electrolyte. In particular, the high solubility of CO2 in carbonate melts has been tentatively attributed to the formation of the pyrocarbonate anion, C2O5(2-). Here we study, by first-principles molecular dynamics simulations, the behaviour of CO2 in molten calcium carbonate. We find that pyrocarbonate forms spontaneously and the identity of the CO2 molecule is quickly lost through O(2-) exchange. The transport of CO2 in this molten carbonate thus occurs in a fashion similar to the Grotthuss mechanism in water, and is three times faster than molecular diffusion. This shows that Grotthuss-like transport is more general than previously thought.

  14. Steam gasification of plant biomass using molten carbonate salts

    International Nuclear Information System (INIS)

    Hathaway, Brandon J.; Honda, Masanori; Kittelson, David B.; Davidson, Jane H.

    2013-01-01

    This paper explores the use of molten alkali-carbonate salts as a reaction and heat transfer medium for steam gasification of plant biomass with the objectives of enhanced heat transfer, faster kinetics, and increased thermal capacitance compared to gasification in an inert gas. The intended application is a solar process in which concentrated solar radiation is the sole source of heat to drive the endothermic production of synthesis gas. The benefits of gasification in a molten ternary blend of lithium, potassium, and sodium carbonate salts is demonstrated for cellulose, switchgrass, a blend of perennial plants, and corn stover through measurements of reaction rate and product composition in an electrically heated reactor. The feedstocks are gasified with steam at 1200 K in argon and in the molten salt. The use of molten salt increases the total useful syngas production by up to 25%, and increases the reactivity index by as much as 490%. Secondary products, in the form of condensable tar, are reduced by 77%. -- Highlights: ► The presence of molten salt increases the rate of gasification by up to 600%. ► Reaction rates across various feedstocks are more uniform with salt present. ► Useful syngas yield is increased by up to 30% when salt is present. ► Secondary production of liquid tars are reduced by 77% when salt is present.

  15. Chemical stability of conductive ceramic anodes in LiCl–Li{sub 2}O molten salt for electrolytic reduction in pyroprocessing

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Wook; Kang, Hyun Woo; Jeon, Min Ku; Lee, Sang Kwon; Choi, Eun Young; Park, Woo Shin; Hong, Sun Seok; Oh, Seung Chul; Hur, Jin Mok [Nuclear Fuel Cycle Process Development Group, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-08-15

    Conductive ceramics are being developed to replace current Pt anodes in the electrolytic reduction of spent oxide fuels in pyroprocessing. While several conductive ceramics have shown promising electrochemical properties in small-scale experiments, their long-term stabilities have not yet been investigated. In this study, the chemical stability of conductive La{sub 0.33}Sr{sub 0.67}MnO{sub 3} in LiCl–Li{sub 2}O molten salt at 650°C was investigated to examine its feasibility as an anode material. Dissolution of Sr at the anode surface led to structural collapse, thereby indicating that the lifetime of the La{sub 0.33}Sr{sub 0.67}MnO{sub 3} anode is limited. The dissolution rate of Sr is likely to be influenced by the local environment around Sr in the perovskite framework.

  16. Molten carbonate fuel cell integral matrix tape and bubble barrier

    International Nuclear Information System (INIS)

    Reiser, C.A.; Maricle, D.L.

    1983-01-01

    A molten carbonate fuel cell matrix material is described made up of a matrix tape portion and a bubble barrier portion. The matrix tape portion comprises particles inert to molten carbonate electrolyte, ceramic particles and a polymeric binder, the matrix tape being flexible, pliable and having rubber-like compliance at room temperature. The bubble barrier is a solid material having fine porosity preferably being bonded to the matrix tape. In operation in a fuel cell, the polymer binder burns off leaving the matrix and bubble barrier providing superior sealing, stability and performance properties to the fuel cell stack

  17. Low temperature molten salt synthesis of Y(sub2)Sn(sub2)O(sub7) anode material for lithium ion batteries

    CSIR Research Space (South Africa)

    Nithyadharseni, P

    2015-10-01

    Full Text Available Acta 182 (2015) 1060–1069 Low temperature molten salt synthesis of Y2Sn2O7 anode material for lithium ion batteries P. Nithyadharsenia,b, M.V. Reddya,c,*, Kenneth I. Ozoemenab,d, R. Geetha Balakrishnae, B.V.R. Chowdaria a Advanced Batteries...

  18. Enhanced ablation of small anodes in a carbon nanotube arc discharge

    Science.gov (United States)

    Raitses, Yevgeny; Fetterman, Abraham; Keidar, Michael

    2008-11-01

    An atmospheric pressure helium arc discharge is used for carbon nanotube synthesis. The arc discharge operates in an anodic mode with the ablating anode made from a graphite material. For such conditions, models predict the electron-repelling (negative) anode sheath. In the present experiments, the anode ablation rate is investigated as a function of the anode diameter. It is found that anomalously high ablation occurs for small anode diameters (Fetterman, Y. Raitses and M. Keidar, Carbon (2008).

  19. Molten salt electrorefining method

    International Nuclear Information System (INIS)

    Tanaka, Hiroshi; Nakamura, Hitoshi; Shoji, Yuichi; Matsumaru, Ken-ichi.

    1994-01-01

    A molten cadmium phase (lower side) and a molten salt phase (upper side) are filled in an electrolytic bath. A basket incorporating spent nuclear fuels is inserted/disposed in the molten cadmium phase. A rotatable solid cathode is inserted/disposed in the molten salt phase. The spent fuels, for example, natural uranium, incorporated in the basket is dissolved in the molten cadmium phase. In this case, the uranium concentration in the molten salt phase is determined as from 0.5 to 20wt%. Then, electrolysis is conducted while setting a stirring power for stirring at least the molten salt phase of from 2.5 x 10 2 to 1 x 10 4 based on a reynolds number. Crystalline nuclei of uranium are precipitated uniformly on the surface of the solid cathode, and they grow into fine dendrites. With such procedures, since short-circuit between the cathode precipitates and the molten cadmium phase (anode) is scarcely caused, to improve the recovering rate of uranium. (I.N.)

  20. Effects of Charcoal Addition on the Properties of Carbon Anodes

    Directory of Open Access Journals (Sweden)

    Asem Hussein

    2017-03-01

    Full Text Available Wood charcoal is an attractive alternative to petroleum coke in production of carbon anodes for the aluminum smelting process. Calcined petroleum coke is the major component in the anode recipe and its consumption results in a direct greenhouse gas (GHG footprint for the industry. Charcoal, on the other hand, is considered as a green and abundant source of sulfur-free carbon. However, its amorphous carbon structure and high contents of alkali and alkaline earth metals (e.g., Na and Ca make charcoal highly reactive to air and CO2. Acid washing and heat treatment were employed in order to reduce the reactivity of charcoal. The pre-treated charcoal was used to substitute up to 10% of coke in the anode recipe in an attempt to investigate the effect of this substitution on final anode properties. The results showed deterioration in the anode properties by increasing the charcoal content. However, by adjusting the anode recipe, this negative effect can be considerably mitigated. Increasing the pitch content was found to be helpful to improve the physical properties of the anodes containing charcoal.

  1. Application of multi-walled carbon nanotubes to enhance anodic ...

    African Journals Online (AJOL)

    The effect of multi-walled carbon nanotube (MWCNT) modification of anodes and the optimisation of relevant parameters thereof for application in an Enterobacter cloacae microbial fuel cell were examined. The H – type microbial fuel cells were used for the fundamental studies, with a carbon sheet as a control anode and ...

  2. Upcycling of Packing-Peanuts into Carbon Microsheet Anodes for Lithium-Ion Batteries.

    Science.gov (United States)

    Etacheri, Vinodkumar; Hong, Chulgi Nathan; Pol, Vilas G

    2015-09-15

    Porous carbon microsheet anodes with Li-ion storage capacity exceeding the theoretical limit are for the first time derived from waste packing-peanuts. Crystallinity, surface area, and porosity of these 1 μm thick carbon sheets were tuned by varying the processing temperature. Anodes composed of the carbon sheets outperformed the electrochemical properties of commercial graphitic anode in Li-ion batteries. At a current density of 0.1 C, carbon microsheet anodes exhibited a specific capacity of 420 mAh/g, which is slightly higher than the theoretical capacity of graphite (372 mAh/g) in Li-ion half-cell configurations. At a higher rate of 1 C, carbon sheets retained 4-fold higher specific capacity (220 mAh/g) compared to those of commercial graphitic anode. After 100 charge-discharge cycles at current densities of 0.1 and 0.2 C, optimized carbon sheet anodes retained stable specific capacities of 460 and 370 mAh/g, respectively. Spectroscopic and microscopic investigations proved the structural integrity of these high-performance carbon anodes during numerous charge-discharge cycles. Considerably higher electrochemical performance of the porous carbon microsheets are endorsed to their disorderness that facilitate to store more Li-ions than the theoretical limit, and porous 2-D microstructure enabling fast solid-state Li-ion diffusion and superior interfacial kinetics. The work demonstrated here illustrates an inexpensive and environmentally benign method for the upcycling of packaging materials into functional carbon materials for electrochemical energy storage.

  3. Demixing and effective volatility of molten alkali carbonate melts in MCFCs

    Energy Technology Data Exchange (ETDEWEB)

    Brenscheidt, T.; Wendt, H. [Institut fuer Chemische Technologie, Darmstadt (Germany)

    1996-12-31

    Since the early investigation of A. Klemm, the demixing of the cations of molten binary salt mixtures with a common anion due to the different mobilities of two different cations had been investigated in numerous experiments and the respective results interpreted in terms of structural features of the melts. 1-1 electrolytes had been preferentially investigated. Okada also reported investigations on lithium carbonate/potassium carbonate mixtures in the temperature range from 980 to 1070 K. From this investigation it is known that the heavier potassium cation is faster than lithium in mixtures which are more concentrated in potassium than x{sub K2CO3} = 0,32 (Chemla effect) whereas below this isotachic concentration lithium is faster. This paper investigates demixing in molten carbonate fuel cells.

  4. In-Operando Raman Characterization of Carbon Deposition on SOFC Anodes

    KAUST Repository

    Maher, R. C.; Duboviks, V.; Offer, G.; Cohen, L. F.; Brandon, N. P.

    2013-01-01

    Carbon formation within nickel-based solid oxide fuel cell (SOFC) anodes exposed to carbonaceous fuels typically leads to reduced operational lifetimes and performance, and can eventually lead to catastrophic failure through cracking and delamination. In-situ Raman spectroscopy has been shown to be a powerful characterization tool for the investigation of the dynamics of physical processes occurring within operational SOFCs in real time. Here we investigate the dynamics of carbon formation on a variety of nickel-based SOFC anodes as a function of temperature, fuel and electrical loading using Raman spectroscopy. We show that the rate of carbon formation throughout the SOFC anode can be significantly reduced through a careful consideration of the SOFC anode material, design and operational conditions. © The Electrochemical Society.

  5. In-Operando Raman Characterization of Carbon Deposition on SOFC Anodes

    KAUST Repository

    Maher, R. C.

    2013-10-06

    Carbon formation within nickel-based solid oxide fuel cell (SOFC) anodes exposed to carbonaceous fuels typically leads to reduced operational lifetimes and performance, and can eventually lead to catastrophic failure through cracking and delamination. In-situ Raman spectroscopy has been shown to be a powerful characterization tool for the investigation of the dynamics of physical processes occurring within operational SOFCs in real time. Here we investigate the dynamics of carbon formation on a variety of nickel-based SOFC anodes as a function of temperature, fuel and electrical loading using Raman spectroscopy. We show that the rate of carbon formation throughout the SOFC anode can be significantly reduced through a careful consideration of the SOFC anode material, design and operational conditions. © The Electrochemical Society.

  6. Carbon paint anode for reinforced concrete bridges in coastal environments

    Energy Technology Data Exchange (ETDEWEB)

    Cramer, Stephen D.; Bullard, Sophie J.; Covino, Bernard S., Jr.; Holcomb, Gordon R.; Russell, James H.; Cryer, C.B. (ODOT); Laylor, H.M. (ODOT)

    2002-01-01

    Solvent-based acrylic carbon paint anodes were installed on the north approach spans of the Yaquina Bay Bridge (Newport OR) in 1985. The anodes continue to perform satisfactorily after more than 15 years service. The anodes were inexpensive to apply and field repairs are easily made. Depolarization potentials are consistently above 100 mV with long-term current densities around 2 mA/m 2. Bond strength remains adequate, averaging 0.50 MPa (73 psi). Some deterioration of the anode-concrete interface has occurred in the form of cracks and about 4% of the bond strength measurements indicated low or no bond. Carbon anode consumption appears low. The dominant long-term anode reaction appears to be chlorine evolution, which results in limited further acidification of the anode-concrete interface. Chloride profiles were depressed compared to some other coastal bridges suggesting chloride extraction by the CP system. Further evidence of outward chloride migration was a flat chloride profile between the anode and the outer rebar.

  7. Recent developments in the modeling of molten carbonate fuel cells

    International Nuclear Information System (INIS)

    Wilemski, G.

    1984-01-01

    Modeling of porous electrodes and overall performance of molten carbonate fuel cells is reviewed. Aspects needing improvement are discussed. Some preliminary results on internal methane reforming cells are presented. Successful modeling of molten carbonate fuel cells has been carried out at two levels. The first concerns the prediction of overall cell performance and performance decay, i.e., the calculation of current-voltage curves and their decay rates for various cell operating conditions. The second involves the determination of individual porous electrode performance, i.e., how the electrode overpotential is affected by pore structure, gas composition, degree of electrolyte fill, etc. Both levels are treated mechanistically, as opposed to empirically, using fundamental mathematical descriptions of the relevant physical and chemical phenomena, in order to provide quantitative predictive capability

  8. Hot corrosion behaviour of austenitic steel-303 in molten chloride and carbonate salts

    International Nuclear Information System (INIS)

    Mohd Misbahul Amin; Shamsul Baharin Jamaludin; Che Mohd Ruzaidi Ghazali; Khairel Rafezi Ahmad

    2007-01-01

    The investigations are presented for the hot corrosion behaviors of Austenitic Steel-303, under influence of the molten chloride and carbonate salts viz KCl and K 2 CO 3 , oxidised at 1123 K for the period of 60 hour at atmospheric condition. The oxidation kinetic are effect of molten chloride and carbonate salts deposition on the oxidation rate were determined. The susceptibility to suffer a deleterious attack on the alloy by internal corrosion increases with increasing the time. In general, the corrosion resistance austenitic steel-303 in molten carbonate salts is much higher than chloride melt, being an active oxidizing agent providing oxygen during fluxing reaction. However, due to profuse evolution of CO/ CO 2 heavy mass losses are observed during corrosion and scales are porous. The test included mass change monitoring and surface layers were examined by means of scanning electron microscopy (SEM) studies. (author)

  9. Research and development issues for molten carbonate fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Krumpelt, M.

    1996-04-01

    This paper describes issues pertaining to the development of molten carbonate fuel cells. In particular, the corrosion resistance and service life of nickel oxide cathodes is described. The resistivity of lithium oxide/iron oxides and improvement with doping is addressed.

  10. Environmental and energy gains from using molten magnesium–sodium–potassium chlorides for electro-metallisation of refractory metal oxides

    Directory of Open Access Journals (Sweden)

    Wei Li

    2015-12-01

    Full Text Available The molten eutectic mixture of magnesium, sodium and potassium chlorides (MgCl2–NaCl–KCl has inappreciable solubility for oxide ions, and can help disengage a carbon anode from the oxide ions generated at a metal oxide cathode, and effectively avoid carbon dioxide formation. This “disengaging strategy” was successfully demonstrated in electro-reduction of solid oxides of zirconium and tantalum. It has led to significantly higher current efficiency (93%, and lower energy consumption (1.4 kW h kg−1 in electrolysis of tantalum oxide to tantalum metal compared to the conventional electrolysis in molten calcium chloride (e.g. 78% and 2.4 kW h/kg-Ta.

  11. Modelling of structure and properties of soft carbons with application to carbon anode baking

    Energy Technology Data Exchange (ETDEWEB)

    Gundersen, Oeyvind

    1998-11-01

    This work deals with topics related to modelling and control of ring furnaces for the baking of carbon anodes used in aluminium electrolysis. Anodes made of a granular coke and coal tar pitch are used in aluminium electrolysis. The anode properties are imperative for successful operation of the aluminium smelters. After mixing and forming the anode paste, heat treatment of the carbon blocks takes place in so-called ring furnaces. A ring furnace consists of a series of heat treatment sections where each section is loaded with a batch of anodes. The heat treatment of the anodes in a section consumes a lot of energy, and the anode properties partly depend on the heat treatment program. Previous work in the field of ring furnace modelling, operation and control is shortly reviewed. Both petroleum coke and coal tar pitch belong to the group of soft carbons. Models for structural parameters and porosity of soft carbons are developed. Furthermore, a new model for pyrolysis of coal tar pitch is proposed. Based on the models for pyrolysis, structure and porosity, new models for properties of single phase carbons and composite anodes are developed. These models are suitable for use in optimization of the baking process. A detailed mathematical model of a part of the heat treatment process is formulated in three spatial dimensions. The model is based on first principle descriptions of fundamental physical and chemical phenomena and the resulting model appears as a set of partial differential equations. The spatial differential operators are discretized by using the finite volume approach. In this way, a high dimensional nonlinear state space model is obtained. The model has been simulated using the method of lines. A vector of quantities which describes the anode properties is defined. This property vector constitutes a systematic definition of anode quality where the quality parameters are calculated as nonlinear transformations of the state space vector. Models are derived

  12. Modelling of structure and properties of soft carbons with application to carbon anode baking

    Energy Technology Data Exchange (ETDEWEB)

    Gundersen, Oeyvind

    1998-11-01

    This work deals with topics related to modelling and control of ring furnaces for the baking of carbon anodes used in aluminium electrolysis. Anodes made of a granular coke and coal tar pitch are used in aluminium electrolysis. The anode properties are imperative for successful operation of the aluminium smelters. After mixing and forming the anode paste, heat treatment of the carbon blocks takes place in so-called ring furnaces. A ring furnace consists of a series of heat treatment sections where each section is loaded with a batch of anodes. The heat treatment of the anodes in a section consumes a lot of energy, and the anode properties partly depend on the heat treatment program. Previous work in the field of ring furnace modelling, operation and control is shortly reviewed. Both petroleum coke and coal tar pitch belong to the group of soft carbons. Models for structural parameters and porosity of soft carbons are developed. Furthermore, a new model for pyrolysis of coal tar pitch is proposed. Based on the models for pyrolysis, structure and porosity, new models for properties of single phase carbons and composite anodes are developed. These models are suitable for use in optimization of the baking process. A detailed mathematical model of a part of the heat treatment process is formulated in three spatial dimensions. The model is based on first principle descriptions of fundamental physical and chemical phenomena and the resulting model appears as a set of partial differential equations. The spatial differential operators are discretized by using the finite volume approach. In this way, a high dimensional nonlinear state space model is obtained. The model has been simulated using the method of lines. A vector of quantities which describes the anode properties is defined. This property vector constitutes a systematic definition of anode quality where the quality parameters are calculated as nonlinear transformations of the state space vector. Models are derived

  13. Novel Non-Carbonate Based Electrolytes for Silicon Anodes

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Ye [Wildcat Discovery Technologies, San Diego, CA (United States); Yang, Johnny [Wildcat Discovery Technologies, San Diego, CA (United States); Cheng, Gang [Wildcat Discovery Technologies, San Diego, CA (United States); Carroll, Kyler [Wildcat Discovery Technologies, San Diego, CA (United States); Clemons, Owen [Wildcat Discovery Technologies, San Diego, CA (United States); Strand, Diedre [Wildcat Discovery Technologies, San Diego, CA (United States)

    2016-09-09

    Substantial improvement in the energy density of rechargeable lithium batteries is required to meet the future needs for electric and plug-in electric vehicles (EV and PHEV). Present day lithium ion battery technology is based on shuttling lithium between graphitic carbon and inorganic oxides. Non-graphitic anodes, such as silicon can provide significant improvements in energy density but are currently limited in cycle life due to reactivity with the electrolyte. Wildcat/3M proposes the development of non-carbonate electrolyte formulations tailored for silicon alloy anodes. Combining these electrolytes with 3M’s anode and an NMC cathode will enable up to a 20% increase in the volumetric cell energy density, while still meeting the PHEV/EV cell level cycle/calendar life goals.

  14. Performance Testing of Molten Regolith Electrolysis with Transfer of Molten Material for the Production of Oxygen and Metals on the Moon

    Science.gov (United States)

    Sibille, Laurent; Sadoway, Donald; Tripathy, Prabhat; Standish, Evan; Sirk, Aislinn; Melendez, Orlando; Stefanescu, Doru

    2010-01-01

    Previously, we have demonstrated the production of oxygen by electrolysis of molten regolith simulants at temperatures near 1600 C. Using an inert anode and suitable cathode, direct electrolysis (no supporting electrolyte) of the molten silicate is carried out, resulting in the production of molten metallic products at the cathode and oxygen gas at the anode. Initial direct measurements of current efficiency have confirmed that the process offer potential advantages of high oxygen production rates in a smaller footprint facility landed on the moon, with a minimum of consumables brought from Earth. We now report the results of a scale-up effort toward the goal of achieving production rates equivalent to 1 metric ton O2/year, a benchmark established for the support of a lunar base. We previously reported on the electrochemical behavior of the molten electrolyte as dependent on anode material, sweep rate and electrolyte composition in batches of 20-200g and at currents of less than 0.5 A. In this paper, we present the results of experiments performed at currents up to 10 Amperes) and in larger volumes of regolith simulant (500 g - 1 kg) for longer durations of electrolysis. The technical development of critical design components is described, including: inert anodes capable of passing continuous currents of several Amperes, container materials selection, direct gas analysis capability to determine the gas components co-evolving with oxygen. To allow a continuous process, a system has been designed and tested to enable the withdrawal of cathodically-reduced molten metals and spent molten oxide electrolyte. The performance of the withdrawal system is presented and critiqued. The design of the electrolytic cell and the configuration of the furnace were supported by modeling the thermal environment of the system in an effort to realize a balance between external heating and internal joule heating. We will discuss the impact these simulations and experimental findings have

  15. Coating applications for the molten carbonate fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Pigeaud, A.; Skok, A.J.; Patel, P.S.; Maru, H.C.

    1981-09-25

    The molten carbonate fuel cell is a highly efficient low polluting fuel-to-electricity conversion device which is at present being developed for power plant and industrial use. Because the alkali carbonates at the operating temperature of 650/sup 0/C are corrosive and the methods employed for sealing the cell lead to certain electrochemical corrosion couples, different types of protective coatings are needed to minimize attack in a cost-effective manner. Besides protective purposes, other opportunities are also described where coating technology can be gainfully employed in this system.

  16. Electrolytic reduction runs of 0.6 kg scale-simulated oxide fuel in a Li{sub 2}O-LiCl molten salt using metal anode shrouds

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Eun-Young, E-mail: eychoi@kaeri.re.kr [Korea Atomic Energy Research Institute, Daedoek-daero 989-111, Yuseong-gu, Daejeon 34057 (Korea, Republic of); Lee, Jeong; Heo, Dong Hyun; Lee, Sang Kwon [Korea Atomic Energy Research Institute, Daedoek-daero 989-111, Yuseong-gu, Daejeon 34057 (Korea, Republic of); Jeon, Min Ku [Korea Atomic Energy Research Institute, Daedoek-daero 989-111, Yuseong-gu, Daejeon 34057 (Korea, Republic of); Department of Quantum Energy Chemical Engineering, University of Science and Technology, Gajeong-ro 217, Yuseong-gu, Daejeon 34113 (Korea, Republic of); Hong, Sun Seok [Korea Atomic Energy Research Institute, Daedoek-daero 989-111, Yuseong-gu, Daejeon 34057 (Korea, Republic of); Kim, Sung-Wook [Korea Atomic Energy Research Institute, Daedoek-daero 989-111, Yuseong-gu, Daejeon 34057 (Korea, Republic of); Department of Quantum Energy Chemical Engineering, University of Science and Technology, Gajeong-ro 217, Yuseong-gu, Daejeon 34113 (Korea, Republic of); Kang, Hyun Woo; Jeon, Sang-Chae; Hur, Jin-Mok [Korea Atomic Energy Research Institute, Daedoek-daero 989-111, Yuseong-gu, Daejeon 34057 (Korea, Republic of)

    2017-06-15

    Ten electrolytic reduction or oxide reduction (OR) runs of a 0.6 kg scale-simulated oxide fuel in a Li{sub 2}O-LiCl molten salt at 650 °C were conducted using metal anode shrouds. During this procedure, an anode shroud surrounds a platinum anode and discharges hot oxygen gas from the salt to outside of the OR apparatus, thereby preventing corrosion of the apparatus. In this study, a number of anode shrouds made of various metals were tested. Each metallic anode shroud consisted of a lower porous shroud for the salt phase and an upper nonporous shroud for the gas phase. A stainless steel (STS) wire mesh with five-ply layer was a material commonly used for the lower porous shroud for the OR runs. The metals tested for the upper nonporous shroud in the different OR runs are STS, nickel, and platinum- or silver-lined nickel. The lower porous shroud showed no significant damage during two consecutive OR runs, but exhibited signs of damage from three or more runs due to thermal stress. The upper nonporous shrouds made up of either platinum- or silver-lined nickel showed excellent corrosion resistance to hot oxygen gas while STS or nickel without any platinum or silver lining exhibited poor corrosion resistance. - Highlights: •Electrolytic reduction runs of a 0.6 kg scale-simulated oxide fuel in a Li{sub 2}O-LiCl molten salt at 650 °C were conducted using metal anode shrouds. •Each metallic anode shroud consisted of a lower porous shroud for the salt phase and an upper nonporous shroud for the gas phase. •The upper nonporous shrouds made up of noble metal-lined nickel showed excellent corrosion resistance to hot oxygen gas.

  17. Low-cost carbon-silicon nanocomposite anodes for lithium ion batteries.

    Science.gov (United States)

    Badi, Nacer; Erra, Abhinay Reddy; Hernandez, Francisco C Robles; Okonkwo, Anderson O; Hobosyan, Mkhitar; Martirosyan, Karen S

    2014-01-01

    The specific energy of the existing lithium ion battery cells is limited because intercalation electrodes made of activated carbon (AC) materials have limited lithium ion storage capacities. Carbon nanotubes, graphene, and carbon nanofibers are the most sought alternatives to replace AC materials but their synthesis cost makes them highly prohibitive. Silicon has recently emerged as a strong candidate to replace existing graphite anodes due to its inherently large specific capacity and low working potential. However, pure silicon electrodes have shown poor mechanical integrity due to the dramatic expansion of the material during battery operation. This results in high irreversible capacity and short cycle life. We report on the synthesis and use of carbon and hybrid carbon-silicon nanostructures made by a simplified thermo-mechanical milling process to produce low-cost high-energy lithium ion battery anodes. Our work is based on an abundant, cost-effective, and easy-to-launch source of carbon soot having amorphous nature in combination with scrap silicon with crystalline nature. The carbon soot is transformed in situ into graphene and graphitic carbon during mechanical milling leading to superior elastic properties. Micro-Raman mapping shows a well-dispersed microstructure for both carbon and silicon. The fabricated composites are used for battery anodes, and the results are compared with commercial anodes from MTI Corporation. The anodes are integrated in batteries and tested; the results are compared to those seen in commercial batteries. For quick laboratory assessment, all electrochemical cells were fabricated under available environment conditions and they were tested at room temperature. Initial electrochemical analysis results on specific capacity, efficiency, and cyclability in comparison to currently available AC counterpart are promising to advance cost-effective commercial lithium ion battery technology. The electrochemical performance observed for

  18. Fabrication of catalytic electrodes for molten carbonate fuel cells

    Science.gov (United States)

    Smith, James L.

    1988-01-01

    A porous layer of catalyst material suitable for use as an electrode in a molten carbonate fuel cell includes elongated pores substantially extending across the layer thickness. The catalyst layer is prepared by depositing particulate catalyst material into polymeric flocking on a substrate surface by a procedure such as tape casting. The loaded substrate is heated in a series of steps with rising temperatures to set the tape, thermally decompose the substrate with flocking and sinter bond the catalyst particles into a porous catalytic layer with elongated pores across its thickness. Employed as an electrode, the elongated pores provide distribution of reactant gas into contact with catalyst particles wetted by molten electrolyte.

  19. Manufacturing method of molten carbonate fuel cell. Yoyu tansan prime en nenryo denchi no seizo hoho

    Energy Technology Data Exchange (ETDEWEB)

    Muneuchi, Atsuo; Murata, Kenji

    1989-09-14

    An fuel electrode of a molten carbonate fuel cell is preliminarily dipped with molten carbonate. This operation is troublesome and reduces the productivity because this operation is made by the fuel electrode unit. In this invention, the carbonate is dipped in the process of temperature elevation after the assembly of the fuel cell. In other words, the carbonate electrode is buried in a groove formed in the fuel electrode leaving a gas flowing space; this fuel electrode is layer-built with a matrix and an oxidant electrode to form a unit cell; this unit cell is assembled to compose a fuel cell; while an anti-oxidant gas is fed to a groove of the fuel electrode, temperature is raised up to the operation level, wherein the carbonnate in the groove is molten to be dipped into the fuel electrode. The anti-oxidant gas is such inactive ones as carbon dioxide, nitrogen, argon and helium. 2 figs.

  20. Porous membrane electrochemical cell for uranium and transuranic recovery from molten salt electrolyte

    Science.gov (United States)

    Willit, James L [Batavia, IL

    2010-09-21

    An improved process and device for the recovery of the minor actinides and the transuranic elements (TRU's) from a molten salt electrolyte. The process involves placing the device, an electrically non-conducting barrier between an anode salt and a cathode salt. The porous barrier allows uranium to diffuse between the anode and cathode, yet slows the diffusion of uranium ions so as to cause depletion of uranium ions in the catholyte. This allows for the eventual preferential deposition of transuranics present in spent nuclear fuel such as Np, Pu, Am, Cm. The device also comprises an uranium oxidation anode. The oxidation anode is solid uranium metal in the form of spent nuclear fuel. The spent fuel is placed in a ferric metal anode basket which serves as the electrical lead or contact between the molten electrolyte and the anodic uranium metal.

  1. Porous membrane electrochemical cell for uranium and transuranic recovery from molten salt electrolyte

    Science.gov (United States)

    Willit, James L.

    2007-09-11

    An improved process and device for the recovery of the minor actinides and the transuranic elements (TRU's) from a molten salt electrolyte. The process involves placing the device, an electrically non-conducting barrier between an anode salt and a cathode salt. The porous barrier allows uranium to diffuse between the anode and cathode, yet slows the diffusion of uranium ions so as to cause depletion of uranium ions in the catholyte. This allows for the eventual preferential deposition of transuranics present in spent nuclear fuel such as Np, Pu, Am, Cm. The device also comprises an uranium oxidation anode. The oxidation anode is solid uranium metal in the form of spent nuclear fuel. The spent fuel is placed in a ferric metal anode basket which serves as the electrical lead or contact between the molten electrolyte and the anodic uranium metal.

  2. Anodic polarization of carbon graphite electrodes in chloride fluoride melts zirconium containing

    International Nuclear Information System (INIS)

    Lyapustin, A.A.; Kanashin, Yu.P.; Nichkov, I.F.; Smyshlyaev, V.Yu.

    1985-01-01

    Polarization of carbon graphite anodes in zircorium containing chloride fluoride melts of the KCl-K 2 ZrF 6 -KF composition at molar ratios [F]:[Zr] being equal to 6, 12, 18, 24, 30 has been studied. K 2 ZrF 6 concentration constitutes 25; 18.9; 15.2; 12.7; 11.8% (by mass), correspondingly. Vitreous carbon (VC-2500), high purity graphite and graphite EhG-0 have been used as anodic materials. Anodic polarization curves have been obtained under electrotype steady-state conditions at 973, 1023, 1073 K. Influence of concentration of fluorine ions in melt on polarization of carbon graphite anodes is shown. Content growth of fluorine ions in melt leads to shift of steady-state anode potentials to their negative values regardless a graphite mark. The most con siderable potential shift on 0.5 V takes plase at molar ratio [F]:[Zr] increasing from 6 to 12. Temperature increase, as measurements showed, doesn't influence greatly on polarization curve shape

  3. Porous carbon-free SnSb anodes for high-performance Na-ion batteries

    Science.gov (United States)

    Choi, Jeong-Hee; Ha, Choong-Wan; Choi, Hae-Young; Seong, Jae-Wook; Park, Cheol-Min; Lee, Sang-Min

    2018-05-01

    A simple melt-spinning/chemical-etching process is developed to create porous carbon-free SnSb anodes. Sodium ion batteries (SIBs) incorporating these anodes exhibit excellent electrochemical performances by accomodating large volume changes during repeated cycling. The porous carbon-free SnSb anode produced by the melt-spinning/chemical-etching process shows a high reversible capacity of 481 mAh g-1, high ICE of 80%, stable cyclability with a high capacity retention of 99% after 100 cycles, and a fast rate capability of 327 mAh g-1 at 4C-rate. Ex-situ X-ray diffraction and high resolution-transmission electron microscopy analyses demonstrate that the synthesized porous carbon-free SnSb anodes involve the highly reversible reaction with sodium through the conversion and recombination reactions during sodiation/desodiation process. The novel and simple melt-spinning/chemical-etching synthetic process represents a technological breakthrough in the commercialization of Na alloy-able anodes for SIBs.

  4. Nickel catalysts for internal reforming in molten carbonate fuel cells

    NARCIS (Netherlands)

    Berger, R.J.; Berger, R.J.; Doesburg, E.B.M.; Doesburg, E.B.M.; van Ommen, J.G.; Ross, J.R.H.; Ross, J.R.H.

    1996-01-01

    Natural gas may be used instead of hydrogen as fuel for the molten carbonate fuel cell (MCFC) by steam reforming the natural gas inside the MCFC, using a nickel catalyst (internal reforming). The severe conditions inside the MCFC, however, require that the catalyst has a very high stability. In

  5. Baking of carbon anodes for the electrolysis of aluminium by electric resistance heating

    Energy Technology Data Exchange (ETDEWEB)

    Schultze-Rhonhof, E.

    1981-09-01

    The aim of the project was the development of a method of baking carbon anodes for the aluminium industry by direct electric resistance heating. A distinct reduction of the energy input compared with the usual methods is possible. At the same time fossil energy (oil, gas) will be substituted by electric energy. An experimental arrangement for baking carbon anodes built during the project baking experiments, in 1:1 scale was realized. The quality of the baked anodes has been investigated. Carbon anodes in a 1:1 scale can be baked uniformly by direct electric resistance heating. The characteristic chemical and physical data meets all requirements of the aluminium industry. The energy input has not yet come up to expectations.

  6. CAPTURING EXHAUST CO2 GAS USING MOLTEN CARBONATE FUEL CELLS

    Directory of Open Access Journals (Sweden)

    Prateek Dhawan

    2016-03-01

    Full Text Available Carbon dioxide is considered as one of the major contenders when the question of greenhouse effect arises. So for any industry or power plant it is of utmost importance to follow certain increasingly stringent environment protection rules and laws. So it is significant to keep eye on any possible methods to reduce carbon dioxide emissions in an efficient way. This paper reviews the available literature so as to try to provide an insight of the possibility of using Molten Carbonate Fuel Cells (MCFCs as the carbon capturing and segregating devices and the various factors that affect the performance of MCFCs during the process of CO2 capture.

  7. Enhanced electrocatalysis performance of amorphous electrolytic carbon from CO2 for oxygen reduction by surface modification in molten salt

    International Nuclear Information System (INIS)

    Chen, Zhigang; Gu, Yuxing; Du, Kaifa; Wang, Xu; Xiao, Wei; Mao, Xuhui; Wang, Dihua

    2017-01-01

    Highlights: •The potential of electrolytic carbon as catalyst for oxygen reduction was evaluated. •A molten salt method for electrolytic-carbon modification was demonstrated. •The electrolytic carbon was activated for the ORR by the molten salt sulfidation. •Sulfur and cobalt dual modification further improved the ORR activity of the carbon. -- Abstract: The electrolytic carbon (E-carbon) derived from greenhouse gas CO 2 in molten carbonates at mild temperature possesses high electrical conductivity and suitable specific surface area. In this work, its potential as catalyst is investigated towards oxygen reduction reaction (ORR). It is revealed that the pristine E-carbon has no electrocatalytic activity for the ORR due to its high surface content of carboxyl group. The carbon was then treated in a Li 2 SO 4 containing Li 2 CO 3 -Na 2 CO 3 -K 2 CO 3 molten salt at 550 °C. Sulfur modified E-carbon was obtained in the melt via a galvanic sulfidation reaction, in which Li 2 SO 4 served as a nontoxic sulfur source and an oxidant. The sulfur modified E-carbon showed a significantly improved electrocatalytic activity. Subsequently, a sulfur/cobalt dual modified carbon with much higher catalysis activity was successfully prepared by treating an E-carbon/CoSO 4 composite in the same melt. The dual modified E-carbon showed excellent catalytic performance with activity close to the commercial Pt/C catalyst but a high tolerance towards methanol.

  8. Factors Affecting Dissolution Resistance of AC Anodizing Al in Sodium Carbonate Solution

    International Nuclear Information System (INIS)

    Abou-Krisha, M.

    2001-01-01

    Studies were performed to determine the effect of different factors on the properties and so the dissolution resistance of the anodic film of Al. Conductance and thermometric measurements were applied to evaluate the dissolution rate. The effect of applied AC voltage concentration of sodium carbonate solution, the anodization time and the temperature of sodium carbonate solutions show a parallel increase in the dissolution resistance of studied Al in hydrochloride acid. The results show that films formed by sodium carbonate solution were of porous type and have pronounced high resistance. Scanning electron microscope and x-ray diffraction further examined the films. The anodic and cathodic behavior and the effect of the scanning rate on the polarization of Al in sodium carbonate solution were studied. The regression analysis was applied to all results. (Author)

  9. Fabrication and oxidation resistance of titanium carbide-coated carbon fibres by reacting titanium hydride with carbon fibres in molten salts

    International Nuclear Information System (INIS)

    Dong, Z.J.; Li, X.K.; Yuan, G.M.; Cong, Y.; Li, N.; Jiang, Z.Y.; Hu, Z.J.

    2009-01-01

    Using carbon fibres and titanium hydride as a reactive carbon source and a metal source, respectively, a protective titanium carbide (TiC) coating was formed on carbon fibres in molten salts, composed of LiCl-KCl-KF, at 750-950 o C. The structure and morphology of the TiC coatings were characterised by X-ray diffraction and scanning electron microscopy, respectively. The oxidation resistance of the TiC-coated carbon fibres was measured by thermogravimetric analysis. The results reveal that control of the coating thickness is very important for improvement of the oxidation resistance of TiC-coated carbon fibres. The oxidative weight loss initiation temperature for the TiC-coated carbon fibres increases significantly when an appropriate coating thickness is used. However, thicker coatings lead to a decrease of the carbon fibres' weight loss initiation temperature due to the formation of cracks in the coating. The TiC coating thickness on carbon fibres can be controlled by adjusting the reaction temperature and time of the molten salt synthesis.

  10. Electrolytic production of metals using a resistant anode

    Science.gov (United States)

    Tarcy, G.P.; Gavasto, T.M.; Ray, S.P.

    1986-11-04

    An electrolytic process is described comprising evolving oxygen on an anode in a molten salt, the anode comprising an alloy comprising a first metal and a second metal, both metals forming oxides, the oxide of the first metal being more resistant than the second metal to attack by the molten salt, the oxide of the second metal being more resistant than the first metal to the diffusion of oxygen. The electrode may also be formed of CuAlO[sub 2] and/or Cu[sub 2]O. 2 figs.

  11. Utilization of corn cob biochar in a direct carbon fuel cell

    Science.gov (United States)

    Yu, Jinshuai; Zhao, Yicheng; Li, Yongdan

    2014-12-01

    Biochar obtained from the pyrolysis of corn cob is used as the fuel of a direct carbon fuel cell (DCFC) employing a composite electrolyte composed of a samarium doped ceria (SDC) and a eutectic carbonate phase. An anode layer made of NiO and SDC is utilized to suppress the cathode corrosion by the molten carbonate and improves the whole cell stability. The anode off-gas of the fuel cell is analyzed with a gas chromatograph. The effect of working temperature on the cell resistance and power output is examined. The maximum power output achieves 185 mW cm-2 at a current density of 340 mA cm-2 and 750 °C. An anode reaction scheme including the Boudouard reaction is proposed.

  12. Carbon Cryogel and Carbon Paper-Based Silicon Composite Anode Materials for Lithium-Ion Batteries

    Science.gov (United States)

    Woodworth, James; Baldwin, Richard; Bennett, William

    2010-01-01

    A variety of materials are under investigation for use as anode materials in lithium-ion batteries, of which, the most promising are those containing silicon. 6 One such material is a composite formed via the dispersion of silicon in a resorcinol-formaldehyde (RF) gel followed by pyrolysis. Two silicon-carbon composite materials, carbon microspheres and nanofoams produced from nano-phase silicon impregnated RF gel precursors have been synthesized and investigated. Carbon microspheres are produced by forming the silicon-containing RF gel into microspheres whereas carbon nano-foams are produced by impregnating carbon fiber paper with the silicon containing RF gel to create a free standing electrode. 1-5 Both materials have demonstrated their ability to function as anodes and utilize the silicon present in the material. Stable reversible capacities above 400 mAh/g for the bulk material and above 1000 mAh/g of Si have been observed.

  13. Effects of Coke Calcination Level on Pore Structure in Carbon Anodes

    Science.gov (United States)

    Fang, Ning; Xue, Jilai; Lang, Guanghui; Bao, Chongai; Gao, Shoulei

    2016-02-01

    Effects of coke calcination levels on pore structure of carbon anodes have been investigated. Bench anodes were prepared by 3 types of cokes with 4 calcination temperatures (800°C, 900°C, 1000°C and 1100°C). The cokes and anodes were characterized using hydrostatic method, air permeability determination, mercury porosimetry, image analysis and confocal microscopy (CSLM). The cokes with different calcination levels are almost the same in LC values (19-20 Å) and real density (1.967-1.985 g/cm3), while the anode containing coke calcined at 900°C has the lowest open porosity and air permeability. Pore size distribution (represented by Anode H sample) can be roughly divided into two ranges: small and medium pores in diameter of 10-400 μm and large pores of 400-580 μm. For the anode containing coke calcined at 800°C, a number of long, narrow pores in the pore size range of 400-580 μm are presented among cokes particles. Formation of these elongated pores may be attributed to coke shrinkages during the anode baking process, which may develop cracking in the anode under cell operations. More small or medium rounded pores with pore size range of 10-400 μm emerge in the anodes with coke calcination temperatures of 900°C, 1000°C and 1100°C, which may be generated due to release of volatiles from the carbon anode during baking. For the anode containing coke calcined at 1100°C, it is found that many rounded pores often closely surround large coke particles, which have potential to form elongated, narrow pores.

  14. Estimation of zirconium in various process streams in molten salt electrorefining process

    International Nuclear Information System (INIS)

    Suganthi, S.; Vandarkuzhali, S.; Venkatesh, P.; Prabhakara Reddy, B.; Nagarajan, K.

    2012-01-01

    Molten salt electrorefining process is a non-aqueous pyrochemical process suitable for reprocessing spent metallic fuel. In this process the spent fuel is taken at the anode and the fuel elements are selectively electrotransported to a suitable cathode (either a solid steel cathode or liquid cadmium cathode) using molten LiCl-KCI as electrolyte. We have demonstrated electrorefining of UZr alloy at engineering scale level. 1 Kg U-6%Zr alloy was taken at the anode and pure uranium was recovered at a steel cathode using molten LiCIKCI-5%UCI 3 as electrolyte at 773 K. In this paper we present the method of dissolution, sample preparation and estimation of zirconium in various process streams in the electrorefining experiments carried out in our laboratory

  15. Anodic Oxidation of Carbon Steel at High Current Densities and Investigation of Its Corrosion Behavior

    Science.gov (United States)

    Fattah-Alhosseini, Arash; Khan, Hamid Yazdani

    2017-06-01

    This work aims at studying the influence of high current densities on the anodization of carbon steel. Anodic protective coatings were prepared on carbon steel at current densities of 100, 125, and 150 A/dm2 followed by a final heat treatment. Coatings microstructures and morphologies were analyzed using X-ray diffraction (XRD) and scanning electron microscope (SEM). The corrosion resistance of the uncoated carbon steel substrate and the anodic coatings were evaluated in 3.5 wt pct NaCl solution through electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements. The results showed that the anodic oxide coatings which were prepared at higher current densities had thicker coatings as a result of a higher anodic forming voltage. Therefore, the anodized coatings showed better anti-corrosion properties compared to those obtained at lower current densities and the base metal.

  16. Hierarchical shell/core CuO nanowire/carbon fiber composites as binder-free anodes for lithium-ion batteries

    International Nuclear Information System (INIS)

    Yuan, Wei; Luo, Jian; Pan, Baoyou; Qiu, Zhiqiang; Huang, Shimin; Tang, Yong

    2017-01-01

    Highlights: •The composite anode is composed of CuO nanowire shell and carbon fiber core. •The composite anode avoids completely the use of binders. •Synergistic effect of carbon fibers and CuO nanowires enhances performance. •Carbon fibers improve electrical conductivity and buffer volume change. •CuO nanowires shorten diffusion length and alleviate structural strain. -- Abstract: Developing high-performance electrode structures is of great importance for advanced lithium-ion batteries. This study reports an efficient method to fabricate hierarchical shell/core CuO nanowire/carbon fiber composites via electroless plating and thermal oxidation processes. With this method, a binder-free CuO nanowire/carbon fiber shell/core hierarchical network composite anode for lithium-ion batteries is successfully fabricated. The morphology and chemical composition of the anode are characterized, and the electrochemical performance of the anode is investigated by standard electrochemical tests. Owing to the superior properties of carbon fibers and the morphological advantages of CuO nanowires, this composite anode still retains an excellent reversible capacity of 598.2 mAh g −1 with a capacity retention rate above 86%, even after 50 cycles, which is much higher than the CuO anode without carbon fibers. Compared to the typical CuO/C electrode systems, the novel binder-free anode yields a performance close to that of the typical core/shell electrode systems and a much higher reversible capacity and capacity retention than the similar shell/core patterns as well as the anodes with binders. It is believed that this novel anode will pave the way to the development of binder-free anodes in response to the increasing demands for high-power energy storage.

  17. Carbon Cryogel Silicon Composite Anode Materials for Lithium Ion Batteries

    Science.gov (United States)

    Woodworth James; Baldwin, Richard; Bennett, William

    2010-01-01

    A variety of materials are under investigation for use as anode materials in lithium-ion batteries, of which, the most promising are those containing silicon. 10 One such material is a composite formed via the dispersion of silicon in a resorcinol-formaldehyde (RF) gel followed by pyrolysis. Two silicon-carbon composite materials, carbon microspheres and nanofoams produced from nano-phase silicon impregnated RF gel precursors have been synthesized and investigated. Carbon microspheres are produced by forming the silicon-containing RF gel into microspheres whereas carbon nano-foams are produced by impregnating carbon fiber paper with the silicon containing RF gel to create a free standing electrode. 1-4,9 Both materials have demonstrated their ability to function as anodes and utilize the silicon present in the material. Stable reversible capacities above 400 mAh/g for the bulk material and above 1000 mAh/g of Si have been observed.

  18. Applications of Carbon Nanotubes for Lithium Ion Battery Anodes

    Directory of Open Access Journals (Sweden)

    Hyoung-Joon Jin

    2013-03-01

    Full Text Available Carbon nanotubes (CNTs have displayed great potential as anode materials for lithium ion batteries (LIBs due to their unique structural, mechanical, and electrical properties. The measured reversible lithium ion capacities of CNT-based anodes are considerably improved compared to the conventional graphite-based anodes. Additionally, the opened structure and enriched chirality of CNTs can help to improve the capacity and electrical transport in CNT-based LIBs. Therefore, the modification of CNTs and design of CNT structure provide strategies for improving the performance of CNT-based anodes. CNTs could also be assembled into free-standing electrodes without any binder or current collector, which will lead to increased specific energy density for the overall battery design. In this review, we discuss the mechanism of lithium ion intercalation and diffusion in CNTs, and the influence of different structures and morphologies on their performance as anode materials for LIBs.

  19. The electrochemical reduction processes of solid compounds in high temperature molten salts.

    Science.gov (United States)

    Xiao, Wei; Wang, Dihua

    2014-05-21

    Solid electrode processes fall in the central focus of electrochemistry due to their broad-based applications in electrochemical energy storage/conversion devices, sensors and electrochemical preparation. The electrolytic production of metals, alloys, semiconductors and oxides via the electrochemical reduction of solid compounds (especially solid oxides) in high temperature molten salts has been well demonstrated to be an effective and environmentally friendly process for refractory metal extraction, functional materials preparation as well as spent fuel reprocessing. The (electro)chemical reduction of solid compounds under cathodic polarizations generally accompanies a variety of changes at the cathode/melt electrochemical interface which result in diverse electrolytic products with different compositions, morphologies and microstructures. This report summarizes various (electro)chemical reactions taking place at the compound cathode/melt interface during the electrochemical reduction of solid compounds in molten salts, which mainly include: (1) the direct electro-deoxidation of solid oxides; (2) the deposition of the active metal together with the electrochemical reduction of solid oxides; (3) the electro-inclusion of cations from molten salts; (4) the dissolution-electrodeposition process, and (5) the electron hopping process and carbon deposition with the utilization of carbon-based anodes. The implications of the forenamed cathodic reactions on the energy efficiency, chemical compositions and microstructures of the electrolytic products are also discussed. We hope that a comprehensive understanding of the cathodic processes during the electrochemical reduction of solid compounds in molten salts could form a basis for developing a clean, energy efficient and affordable production process for advanced/engineering materials.

  20. Electrical conductivity of molten carbonate and carbonate-chloride systems coexisting with aluminium oxide powder

    Energy Technology Data Exchange (ETDEWEB)

    Nikolaeva, Elena V. [Institute of High Temperature Electrochemistry, Yekaterinburg (Russian Federation); Ural Federal Univ., Yekaterinburg (Russian Federation); Ural State Economic Univ., Yekaterinburg (Russian Federation); Bovet, Andrey L.; Zakiryanova, Irina D. [Institute of High Temperature Electrochemistry, Yekaterinburg (Russian Federation); Ural Federal Univ., Yekaterinburg (Russian Federation)

    2018-04-01

    The electrical properties of composite electrolytes (suspensions) composed of α-Al{sub 2}O{sub 3} powder and molten carbonate eutectic (Li{sub 2}CO{sub 3}-Na{sub 2}CO{sub 3}-K{sub 2}CO{sub 3}){sub eut} or molten carbonate-chloride mixture 0.72(Li{sub 2}CO{sub 3}-Na{sub 2}CO{sub 3}-K{sub 2}CO{sub 3}){sub eut}-0.28NaCl have been investigated by AC impedance method. This system shows a dependence of the electrical conductivity upon the temperature and the α-Al{sub 2}O{sub 3} content. The specific electrical conductivity of the α-Al{sub 2}O{sub 3}/(Li{sub 2}CO{sub 3}-Na{sub 2}CO{sub 3}-K{sub 2}CO{sub 3}){sub eut} system can be adequately described by the Maxwell equation for two-phase heterogeneous materials. The regression equation for the dependence of the specific conductivity of the α-Al{sub 2}O{sub 3}/(Li{sub 2}CO{sub 3}-Na{sub 2}CO{sub 3}-K{sub 2}CO{sub 3}){sub eut} composite on the aluminium oxide concentration and temperature was obtained.

  1. Carboxyl functionalization of carbon fibers via aryl diazonium reaction in molten urea to enhance interfacial shear strength

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yuwei [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Meng, Linghui [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Fan, Liquan [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Wu, Guangshun; Ma, Lichun; Zhao, Min [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Huang, Yudong, E-mail: ydhuang.hit1@yahoo.com.cn [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China)

    2016-01-30

    Graphical abstract: - Highlights: • Carbon fibers are functionalized with benzoic acid groups via aryl diazonium reaction. • Interfacial shear strength of the carbon fibers increases by 66%. • Tensile strength of the carbon fibers is preserved after grafting reaction. • The treatment in molten urea can improve modification efficiency greatly. • Using molten urea as the reaction medium can avoid pollution from organic solvents. - Abstract: Using molten urea as the solvent, carbon fibers were functionalized with carboxylic acid groups via aryl diazonium reaction in 15 min to improve their interfacial bonding with epoxy resin. The surface functionalization was quantified by X-ray photoelectron spectroscopy, which showed that the relative surface coverage of carboxylic acid groups increased from an initial percentage of 3.17–10.41%. Mechanical property test results indicated that the aryl diazonium reaction in this paper could improve the interfacial shear strength by 66%. Meanwhile, the technique did not adopt any pre-oxidation step to produce functional groups prior to grafting and was shown to maintain the tensile strength of the fibers. This methodology provided a rapid, facile and economically viable route to produce covalently functionalized carbon fibers in large quantities with an eco-friendly method.

  2. Carboxyl functionalization of carbon fibers via aryl diazonium reaction in molten urea to enhance interfacial shear strength

    International Nuclear Information System (INIS)

    Wang, Yuwei; Meng, Linghui; Fan, Liquan; Wu, Guangshun; Ma, Lichun; Zhao, Min; Huang, Yudong

    2016-01-01

    Graphical abstract: - Highlights: • Carbon fibers are functionalized with benzoic acid groups via aryl diazonium reaction. • Interfacial shear strength of the carbon fibers increases by 66%. • Tensile strength of the carbon fibers is preserved after grafting reaction. • The treatment in molten urea can improve modification efficiency greatly. • Using molten urea as the reaction medium can avoid pollution from organic solvents. - Abstract: Using molten urea as the solvent, carbon fibers were functionalized with carboxylic acid groups via aryl diazonium reaction in 15 min to improve their interfacial bonding with epoxy resin. The surface functionalization was quantified by X-ray photoelectron spectroscopy, which showed that the relative surface coverage of carboxylic acid groups increased from an initial percentage of 3.17–10.41%. Mechanical property test results indicated that the aryl diazonium reaction in this paper could improve the interfacial shear strength by 66%. Meanwhile, the technique did not adopt any pre-oxidation step to produce functional groups prior to grafting and was shown to maintain the tensile strength of the fibers. This methodology provided a rapid, facile and economically viable route to produce covalently functionalized carbon fibers in large quantities with an eco-friendly method.

  3. Silicon Composite Anode Materials for Lithium Ion Batteries Based on Carbon Cryogels and Carbon Paper

    Science.gov (United States)

    Woodworth, James; Baldwin, Richard; Bennett, William

    2010-01-01

    A variety of materials are under investigation for use as anode materials in lithium-ion batteries, of which, the most promising are those containing silicon. One such material is a composite formed via the dispersion of silicon in a resorcinol-formaldehyde (RF) gel followed by pyrolysis. Two silicon-carbon composite materials, carbon microspheres and nanofoams produced from nano-phase silicon impregnated RF gel precursors have been synthesized and investigated. Carbon microspheres are produced by forming the silicon-containing RF gel into microspheres whereas carbon nanofoams are produced by impregnating carbon fiber paper with the silicon containing RF gel to create a free standing electrode. Both materials have demonstrated their ability to function as anodes and utilize the silicon present in the material. Stable reversible capacities above 400 mAh/g for the bulk material and above 1000 mAh/g of Si have been observed.

  4. Electrolytic reduction runs of 0.6 kg scale-simulated oxide fuel in a Li2O-LiCl molten salt using metal anode shrouds

    Science.gov (United States)

    Choi, Eun-Young; Lee, Jeong; Heo, Dong Hyun; Lee, Sang Kwon; Jeon, Min Ku; Hong, Sun Seok; Kim, Sung-Wook; Kang, Hyun Woo; Jeon, Sang-Chae; Hur, Jin-Mok

    2017-06-01

    Ten electrolytic reduction or oxide reduction (OR) runs of a 0.6 kg scale-simulated oxide fuel in a Li2O-LiCl molten salt at 650 °C were conducted using metal anode shrouds. During this procedure, an anode shroud surrounds a platinum anode and discharges hot oxygen gas from the salt to outside of the OR apparatus, thereby preventing corrosion of the apparatus. In this study, a number of anode shrouds made of various metals were tested. Each metallic anode shroud consisted of a lower porous shroud for the salt phase and an upper nonporous shroud for the gas phase. A stainless steel (STS) wire mesh with five-ply layer was a material commonly used for the lower porous shroud for the OR runs. The metals tested for the upper nonporous shroud in the different OR runs are STS, nickel, and platinum- or silver-lined nickel. The lower porous shroud showed no significant damage during two consecutive OR runs, but exhibited signs of damage from three or more runs due to thermal stress. The upper nonporous shrouds made up of either platinum- or silver-lined nickel showed excellent corrosion resistance to hot oxygen gas while STS or nickel without any platinum or silver lining exhibited poor corrosion resistance.

  5. Development of large scale internal reforming molten carbonate fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, A.; Shinoki, T.; Matsumura, M. [Mitsubishi Electric Corp., Hyogo (Japan)

    1996-12-31

    Internal Reforming (IR) is a prominent scheme for Molten Carbonate Fuel Cell (MCFC) power generating systems in order to get high efficiency i.e. 55-60% as based on the Higher Heating Value (HHV) and compact configuration. The Advanced Internal Reforming (AIR) technology has been developed based on two types of the IR-MCFC technology i.e. Direct Internal Reforming (DIR) and Indirect Internal Reforming (DIR).

  6. Three-Dimensional Carbon Nanotube−Textile Anode for High-Performance Microbial Fuel Cells

    KAUST Repository

    Xie, Xing; Hu, Liangbing; Pasta, Mauro; Wells, George F.; Kong, Desheng; Criddle, Craig S.; Cui, Yi

    2011-01-01

    Microbial fuel cells (MFCs) harness the metabolism of microorganisms, converting chemical energy into electrical energy. Anode performance is an important factor limiting the power density of MFCs for practical application. Improving the anode design is thus important for enhancing the MFC performance, but only a little development has been reported. Here, we describe a biocompatible, highly conductive, two-scale porous anode fabricated from a carbon nanotube-textile (CNT-textile) composite for high-performance MFCs. The macroscale porous structure of the intertwined CNT-textile fibers creates an open 3D space for efficient substrate transport and internal colonization by a diverse microflora, resulting in a 10-fold-larger anolyte-biofilm-anode interfacial area than the projective surface area of the CNT-textile. The conformally coated microscale porous CNT layer displays strong interaction with the microbial biofilm, facilitating electron transfer from exoelectrogens to the CNT-textile anode. An MFC equipped with a CNT-textile anode has a 10-fold-lower charge-transfer resistance and achieves considerably better performance than one equipped with a traditional carbon cloth anode: the maximum current density is 157% higher, the maximum power density is 68% higher, and the energy recovery is 141% greater. © 2011 American Chemical Society.

  7. Three-Dimensional Carbon Nanotube−Textile Anode for High-Performance Microbial Fuel Cells

    KAUST Repository

    Xie, Xing

    2011-01-12

    Microbial fuel cells (MFCs) harness the metabolism of microorganisms, converting chemical energy into electrical energy. Anode performance is an important factor limiting the power density of MFCs for practical application. Improving the anode design is thus important for enhancing the MFC performance, but only a little development has been reported. Here, we describe a biocompatible, highly conductive, two-scale porous anode fabricated from a carbon nanotube-textile (CNT-textile) composite for high-performance MFCs. The macroscale porous structure of the intertwined CNT-textile fibers creates an open 3D space for efficient substrate transport and internal colonization by a diverse microflora, resulting in a 10-fold-larger anolyte-biofilm-anode interfacial area than the projective surface area of the CNT-textile. The conformally coated microscale porous CNT layer displays strong interaction with the microbial biofilm, facilitating electron transfer from exoelectrogens to the CNT-textile anode. An MFC equipped with a CNT-textile anode has a 10-fold-lower charge-transfer resistance and achieves considerably better performance than one equipped with a traditional carbon cloth anode: the maximum current density is 157% higher, the maximum power density is 68% higher, and the energy recovery is 141% greater. © 2011 American Chemical Society.

  8. Molten carbonate fuel cell cathode with mixed oxide coating

    Science.gov (United States)

    Hilmi, Abdelkader; Yuh, Chao-Yi

    2013-05-07

    A molten carbonate fuel cell cathode having a cathode body and a coating of a mixed oxygen ion conductor materials. The mixed oxygen ion conductor materials are formed from ceria or doped ceria, such as gadolinium doped ceria or yttrium doped ceria. The coating is deposited on the cathode body using a sol-gel process, which utilizes as precursors organometallic compounds, organic and inorganic salts, hydroxides or alkoxides and which uses as the solvent water, organic solvent or a mixture of same.

  9. Active control of methanol carbonylation selectivity over Au/carbon anode by electrochemical potential.

    Science.gov (United States)

    Funakawa, Akiyasu; Yamanaka, Ichiro; Otsuka, Kiyoshi

    2005-05-12

    Electrochemical oxidative carbonylation of methanol was studied over Au supported carbon anode in CO. The major carbonylation products were dimethyl oxalate (DMO) and dimethyl carbonate (DMC). The minor oxidation products were dimethoxy methane (DMM) and methyl formate (MF) from methanol and CO(2). Influences of various reaction conditions were studied on carbonylation activities and selectivities. The selectivities to DMO and DMC can be controlled by the electrochemical potential. Electrocatalysis of Au/carbon anode was studied by cyclic voltammetry (CV), stoichiometric reactions among Au(3+), methanol, and CO, and UV-vis spectra. The Au/carbon anode was characterized by XRD, SEM, and BE images before and after the carbonylation. These experimental facts strongly suggest that transition of oxidation states of Au affects changing of the carbonylation selectivities to DMO and DMC. Au(0) is the active species for the selective DMO formation by direct electrochemical carbonylation at low potentials (selective DMC formation by indirect electrochemical carbonylation through Au(3+)/Au(+) redox at high potentials (>+1.3 V).

  10. Carbon deposition thresholds on nickel-based solid oxide fuel cell anodes II. Steam:carbon ratio and current density

    Science.gov (United States)

    Kuhn, J.; Kesler, O.

    2015-03-01

    For the second part of a two part publication, coking thresholds with respect to molar steam:carbon ratio (SC) and current density in nickel-based solid oxide fuel cells were determined. Anode-supported button cell samples were exposed to 2-component and 5-component gas mixtures with 1 ≤ SC ≤ 2 and zero fuel utilization for 10 h, followed by measurement of the resulting carbon mass. The effect of current density was explored by measuring carbon mass under conditions known to be prone to coking while increasing the current density until the cell was carbon-free. The SC coking thresholds were measured to be ∼1.04 and ∼1.18 at 600 and 700 °C, respectively. Current density experiments validated the thresholds measured with respect to fuel utilization and steam:carbon ratio. Coking thresholds at 600 °C could be predicted with thermodynamic equilibrium calculations when the Gibbs free energy of carbon was appropriately modified. Here, the Gibbs free energy of carbon on nickel-based anode support cermets was measured to be -6.91 ± 0.08 kJ mol-1. The results of this two part publication show that thermodynamic equilibrium calculations with appropriate modification to the Gibbs free energy of solid-phase carbon can be used to predict coking thresholds on nickel-based anodes at 600-700 °C.

  11. Niobium electrodeposition from molten fluorides

    International Nuclear Information System (INIS)

    Sartori, A.F.

    1987-01-01

    Niobium electrodeposition from molten alkali fluorides has been studied aiming the application of this technic to the processes of electrorefining and galvanotechnic of this metal. The effects of current density, temperature, niobium concentration in the bath, electrolysis time, substrate nature, ratio between anodic and cathodic areas, electrodes separation and the purity of anodes were investigated in relation to the cathodic current efficiency, electrorefining, electroplating and properties of the deposit and the electrolytic solution. The work also gives the results of the conctruction and operation of a pilot plant for refractory metals electrodeposition and shows the electrorefining and electroplating compared to those obtained at the laboratory scale. (author) [pt

  12. Voltammetric and impedance study of the influence of the anode composition on the electrochemical ferrate(VI) production in molten NaOH

    International Nuclear Information System (INIS)

    Hrnčiariková, Lucia; Gál, Miroslav; Kerekeš, Kamil; Híveš, Ján

    2013-01-01

    Three typical anode materials: pure iron (Fe), silicon-rich steel (FeSi) and white cast iron (FeC) electrodes were used in the process of electrochemical ferrate(VI) synthesis in the molten sodium hydroxide. The voltammetric peak current densities corresponding to the first and second step of the anode dissolution in the case of FeC as well as FeSi electrode are higher compared to the pure iron electrode. After passivity region subsequently the transpassive iron dissolution, including ferrate(VI) formation together with an oxygen evolution occurs and the current shoulder is visible for all electrodes used. Measured electrochemical impedance spectra confirm the physical model of the polarized surface based on the concept of two macrohomogeneous surface layers. In all cases the resistance of both inner and outer layer decrease with increasing applied potential. With increasing temperature the resistance of inner and outer layer decreases. The capacity of inner and outer layer increases with increasing potential. This is in agreement with decrease of the resistances of both layers: layers are getting thinner or more disintegrated by oxygen evolution or strong anodic dissolution. The number of exchanged electrons calculated from a static polarization curve at the potentials in ferrate(VI) formation region is z = 3 for all electrode materials used

  13. Aluminum as anode for energy storage and conversion: a review

    Science.gov (United States)

    Li, Qingfeng; Bjerrum, Niels J.

    Aluminum has long attracted attention as a potential battery anode because of its high theoretical voltage and specific energy. The protective oxide layer on the aluminum surface is however detrimental to the battery performance, contributing to failure to achieve the reversible potential and causing the delayed activation of the anode. By developing aluminum alloys as anodes and solution additives to electrolytes, a variety of aluminum batteries have been extensively investigated for various applications. From molten salt and other non-aqueous electrolytes, aluminum can be electrodeposited and therefore be suitable for developing rechargable batteries. Considerable efforts have been made to develop secondary aluminum batteries of high power density. In the present paper, these research activities are reviewed, including aqueous electrolyte primary batteries, aluminum-air batteries and molten salt secondary batteries.

  14. Solvent anode for plutonium purification

    International Nuclear Information System (INIS)

    Bowersox, D.F.; Fife, K.W.; Christensen, D.C.

    1986-01-01

    The purpose of this study is to develop a technique to allow complete oxidation of plutonium from the anode during plutonium electrorefining. This will eliminate the generation of a ''spent'' anode heel which requires further treatment for recovery. Our approach is to employ a solvent metal in the anode to provide a liquid anode pool throughout electrorefining. We use molten salts and metals in ceramic crucibles at 700 0 C. Our goal is to produce plutonium metal at 99.9% purity with oxidation and transfer of more than 98% of the impure plutonium feed metal from the anode into the salt and product phases. We have met these criteria in experiments on the 100 to 1000 g scale. We plan to scale our operations to 4 kg of feed plutonium and to optimize the process parameters

  15. Molten Triazolium Chloride Systems as New Aluminum Battery Electrolytes

    DEFF Research Database (Denmark)

    Vestergaard, B.; Bjerrum, Niels; Petrushina, Irina

    1993-01-01

    -170-degrees-C) depending on melt acidity and anode material. DMTC, being specifically adsorbed and reduced on the tungsten electrode surface, had an inhibiting effect on the aluminum reduction, but this effect was suppressed on the aluminum substrate. An electrochemical process with high current density (tens...... of milliamperes per square centimeter) was observed at 0.344 V on the acidic sodium tetrachloroaluminate background, involving a free triazolium radical mechanism. Molten DMTC-AlCl3 electrolytes are acceptable for battery performance and both the aluminum anode and the triazolium electrolyte can be used as active......The possibility of using molten mixtures of 1,4-dimethyl-1,2,4-triazolium chloride (DMTC) and aluminum chloride (AlCl3) as secondary battery electrolytes was studied, in some cases extended by the copresence of sodium chloride. DMTC-AlCl, mixtures demonstrated high specific conductivity in a wide...

  16. Anti corrosion layer for stainless steel in molten carbonate fuel cell - comprises phase vapour deposition of titanium nitride, aluminium nitride or chromium nitride layer then oxidising layer in molten carbonate electrolyte

    DEFF Research Database (Denmark)

    2000-01-01

    Forming an anticorrosion protective layer on a stainless steel surface used in a molten carbonate fuel cell (MCFC) - comprises the phase vapour deposition (PVD) of a layer comprising at least one of titanium nitride, aluminium nitride or chromium nitride and then forming a protective layer in situ...

  17. The spectral emissivity of the anode of a carbon arc.

    Science.gov (United States)

    Schurer, K

    1968-03-01

    Data in the literature on the spectral emissivity of carbon and graphite show a great divergence, ranging from 0.75 to 0.99 in the visible region. A new determination has been undertaken at a number of wavelengths using an integrating sphere and modulated light. Emissivities ranging from 0.99 in the visible to 0.96 at 0.28 micro and 1.7 micro have been found for several different graphite anodes; the values for lampblack anodes are about 0.005 lower. There is a good agreement with the highest values thus far published. Most of the literature data on the spectral radiance of the anode are consistent with the emissivities found by the present author.

  18. Anode sheath transition in an anodic arc for synthesis of nanomaterials

    Science.gov (United States)

    Nemchinsky, V. A.; Raitses, Y.

    2016-06-01

    The arc discharge with ablating anode or so-called anodic arc is widely used for synthesis of nanomaterials, including carbon nanotubes and fullerens, metal nanoparticles etc. We present the model of this arc, which confirms the existence of the two different modes of the arc operation with two different anode sheath regimes, namely, with negative anode sheath and with positive anode sheath. It was previously suggested that these regimes are associated with two different anode ablating modes—low ablation mode with constant ablation rate and the enhanced ablation mode (Fetterman et al 2008 Carbon 46 1322). The transition of the arc operation from low ablation mode to high ablation mode is determined by the current density at the anode. The model can be used to self-consistently determine the distribution of the electric field, electron density and electron temperature in the near-anode region of the arc discharge. Simulations of the carbon arc predict that for low arc ablating modes, the current is driven mainly by the electron diffusion to the anode. For positive anode sheath, the anode voltage is close to the ionization potential of anode material, while for negative anode sheath, the anode voltage is an order of magnitude smaller. It is also shown that the near-anode plasma, is far from the ionization equilibrium.

  19. Anode sheath transition in an anodic arc for synthesis of nanomaterials

    International Nuclear Information System (INIS)

    Nemchinsky, V A; Raitses, Y

    2016-01-01

    The arc discharge with ablating anode or so-called anodic arc is widely used for synthesis of nanomaterials, including carbon nanotubes and fullerens, metal nanoparticles etc. We present the model of this arc, which confirms the existence of the two different modes of the arc operation with two different anode sheath regimes, namely, with negative anode sheath and with positive anode sheath. It was previously suggested that these regimes are associated with two different anode ablating modes—low ablation mode with constant ablation rate and the enhanced ablation mode (Fetterman et al 2008 Carbon 46 1322). The transition of the arc operation from low ablation mode to high ablation mode is determined by the current density at the anode. The model can be used to self-consistently determine the distribution of the electric field, electron density and electron temperature in the near-anode region of the arc discharge. Simulations of the carbon arc predict that for low arc ablating modes, the current is driven mainly by the electron diffusion to the anode. For positive anode sheath, the anode voltage is close to the ionization potential of anode material, while for negative anode sheath, the anode voltage is an order of magnitude smaller. It is also shown that the near-anode plasma, is far from the ionization equilibrium. (paper)

  20. Modeling and simulation of NiO dissolution and Ni deposition in molten carbonate fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Suk Woo; Choi, Hyung-Joon; Lim, Tae Hoon [Korea Institute of Science & Technology, Seoul (Korea, Republic of)] [and others

    1996-12-31

    Dissolution of NiO cathode into the electrolyte matrix is an important phenomena limiting the lifetime of molten carbonate fuel cell (MCFC). The dissolved nickel diffuses into the matrix and is reduced by dissolved hydrogen leading to the formation of metallic nickel films in the pores of the matrix. The growth of Ni films in the electrolyte matrix during the continuous cell operation results eventually in shorting between cathode and anode. Various mathematical and empirical models have been developed to describe the NiO dissolution and Ni deposition processes, and these models have some success in estimating the lifetime of MCFC by correlating the amount of Ni deposited in the matrix with shorting time. Since the exact mechanism of Ni deposition was not well understood, deposition reaction was assumed to be very fast in most of the models and the Ni deposition region was limited around a point in the matrix. In fact, formation of Ni films takes place in a rather broad region in the matrix, the location and thickness of the film depending on operating conditions as well as matrix properties. In this study, we assumed simple reaction kinetics for Ni deposition and developed a mathematical model to get the distribution of nickel in the matrix.

  1. Borohydride electro-oxidation in a molten alkali hydroxide eutectic mixture and a novel borohydride-periodate battery

    Science.gov (United States)

    Wang, Andrew; Gyenge, Előd L.

    2015-05-01

    The electrochemical oxidation of BH4- in a molten NaOH-KOH eutectic mixture (0.515:0.485 mole fractions), is investigated for the first time by cyclic voltammetry and electrochemical impedance spectroscopy. Anodically oxidized Ni is electrocatalytically more active than Pt for BH4- oxidation in the molten alkali electrolyte as shown by the more than three times higher exchange current density (i.e. 15.8 mA cm-2 vs. 4.6 mA cm-2 at 185 °C). Next the proof-of-concept for a novel BH4-/IO4- molten alkali electrolyte battery is presented. Using oxidized Ni mesh anode and Pt mesh cathode a maximum power density of 63 mW cm-2 is achieved at 185 °C.

  2. Effect of the graphite electrode material on the characteristics of molten salt electrolytically produced carbon nanomaterials

    International Nuclear Information System (INIS)

    Kamali, Ali Reza; Schwandt, Carsten; Fray, Derek J.

    2011-01-01

    The electrochemical erosion of a graphite cathode during the electrolysis of molten lithium chloride salt may be used for the preparation of nano-structured carbon materials. It has been found that the structures and morphologies of these carbon nanomaterials are dependent on those of the graphite cathodes employed. A combination of tubular and spherical carbon nanostructures has been produced from a graphite with a microstructure of predominantly planar micro-sized grains and a minor fraction of more irregular nano-sized grains, whilst only spherical carbon nanostructures have been produced from a graphite with a microstructure of primarily nano-sized grains. Based on the experimental results, a best-fit regression equation is proposed that relates the crystalline domain size of the graphite reactants and the carbon products. The carbon nanomaterials prepared possess a fairly uniform mesoporosity with a sharp peak in pore size distribution at around 4 nm. The results are of crucial importance to the production of carbon nanomaterials by way of the molten salt electrolytic method. - Highlights: → Carbon nanomaterials are synthesised by LiCl electrolysis with graphite electrodes. → The degree of crystallinity of graphite reactant and carbon product are related. → A graphite reactant is identified that enables the preparation of carbon nanotubes. → The carbon products possess uniform mesoporosity with narrow pore size distribution.

  3. Microporous carbon derived from polyaniline base as anode material for lithium ion secondary battery

    International Nuclear Information System (INIS)

    Xiang, Xiaoxia; Liu, Enhui; Huang, Zhengzheng; Shen, Haijie; Tian, Yingying; Xiao, Chengyi; Yang, Jingjing; Mao, Zhaohui

    2011-01-01

    Highlights: → Nitrogen-containing microporous carbon was prepared from polyaniline base by K 2 CO 3 activation, and used as anode material for lithium ion secondary battery. → K 2 CO 3 activation promotes the formation of amorphous and microporous structure. → High nitrogen content, and large surface area with micropores lead to strong intercalation between carbon and lithium ion, and thus improve the lithium storage capacity. -- Abstract: Microporous carbon with large surface area was prepared from polyaniline base using K 2 CO 3 as an activating agent. The physicochemical properties of the carbon were characterized by scanning electron microscope, X-ray diffraction, Brunauer-Emmett-Teller, elemental analyses and X-ray photoelectron spectroscopy measurement. The electrochemical properties of the microporous carbon as anode material in lithium ion secondary battery were evaluated. The first discharge capacity of the microporous carbon was 1108 mAh g -1 , whose first charge capacity was 624 mAh g -1 , with a coulombic efficiency of 56.3%. After 20 cycling tests, the microporous carbon retains a reversible capacity of 603 mAh g -1 at a current density of 100 mA g -1 . These results clearly demonstrated the potential role of microporous carbon as anode for high capacity lithium ion secondary battery.

  4. Carbon deposition thresholds on nickel-based solid oxide fuel cell anodes I. Fuel utilization

    Science.gov (United States)

    Kuhn, J.; Kesler, O.

    2015-03-01

    In the first of a two part publication, the effect of fuel utilization (Uf) on carbon deposition rates in solid oxide fuel cell nickel-based anodes was studied. Representative 5-component CH4 reformate compositions (CH4, H2, CO, H2O, & CO2) were selected graphically by plotting the solutions to a system of mass-balance constraint equations. The centroid of the solution space was chosen to represent a typical anode gas mixture for each nominal Uf value. Selected 5-component and 3-component gas mixtures were then delivered to anode-supported cells for 10 h, followed by determination of the resulting deposited carbon mass. The empirical carbon deposition thresholds were affected by atomic carbon (C), hydrogen (H), and oxygen (O) fractions of the delivered gas mixtures and temperature. It was also found that CH4-rich gas mixtures caused irreversible damage, whereas atomically equivalent CO-rich compositions did not. The coking threshold predicted by thermodynamic equilibrium calculations employing graphite for the solid carbon phase agreed well with empirical thresholds at 700 °C (Uf ≈ 32%); however, at 600 °C, poor agreement was observed with the empirical threshold of ∼36%. Finally, cell operating temperatures correlated well with the difference in enthalpy between the supplied anode gas mixtures and their resulting thermodynamic equilibrium gas mixtures.

  5. Coaxial Manganese Dioxide@N-doped Carbon Nanotubes as Superior Anodes for Lithium Ion Batteries

    International Nuclear Information System (INIS)

    Yue, Jie; Gu, Xin; Jiang, Xiaolei; Chen, Liang; Wang, Nana; Yang, Jian; Ma, Xiaojian

    2015-01-01

    Highlights: • MnO 2 @N-dopedcarbonnanotube(N-CNT) composites are prepared by a facile process. • MnO 2 @N-CNT anodes exhibit better electrochemical properties than MnO 2 @CNT. • MnO 2 @N-CNT anodes show a capacity of 1415 mAh g −1 at 100 mA g −1 after 150 cycles. - Abstract: Carbon nanotube (CNT) has been widely applied to transition metal oxides anodes for lithium ion batteries, acting as a buffer, hollow backbone and conductive additive. Since the presence of N in carbon materials can enhance the reactivity and electrical conductivity, N-doped carbon nanotube (N-CNT) might be a better choice than pure CNT, which is exemplified by coaxial manganese dioxide@N-doped carbon nanotubes as a superior anode. The electrochemical properties of MnO 2 @N-CNT are investigated in terms of cycling stability and rate capability. The nanocomposite can deliver a specific capacity of 1415 mAh g −1 after 100 cycles at the current density of 100 mA g −1 , which is better than that of MnO 2 @commercial CNT and MnO 2 . The excellent performance might be related to the integration of hollow structure, one-dimensional nanoscale size as well as combination with N-doped carbon materials.

  6. Coaxial silicon/multi-walled carbon nanotube nanocomposite anodes for long cycle life lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Tocoglu, Ubeyd, E-mail: utocoglu@sakarya.edu.tr; Cevher, Ozgur; Guler, M. Oguz; Akbulut, Hatem

    2014-06-01

    Abstract: In this work silicon/multi walled carbon nanotube (MWCNT) composite anodes were produced via direct current (DC) magnetron sputtering of silicon onto carbon nanotube papers (buckypapers). The amount of silicon in the composite anodes was varied by using different sputtering powers of 150 W, 175 W, 200 W and the effect on the cell performance was studied. Phase analysis was conducted with X-ray diffraction (XRD) technique and Raman spectroscopy. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) analyses were employed for morphological characterization of anodes. Energy dispersive spectroscopy (EDS) mapping was used to observe silicon distribution on the buckypapers. Cyclic voltammetry (CV) tests were carried out to reveal reversible reactions between silicon and lithium. Galvanostatic charge/discharge technique was employed to determine the cyclic performance of anodes. Electrochemical impedance spectroscopy technique was used to understand the relation between cyclic performance and internal resistance of cells. The results showed capacity retention of silicon anodes was improved with composite structure and higher capacity values were achieved than graphite anodes. The silicon/carbon nanotube composite produced with 150 W showed the best cycle stability after 100 cycles of galvanostatic charge/discharge tests with capacity value of 620 mAh g{sup −1}.

  7. Electrolyte loss mechanism of molten carbonate fuel cells. 1; Yoyu tansan`engata nenryo denchi ni okeru denkaishitsu loss kiko ni tsuite. 1

    Energy Technology Data Exchange (ETDEWEB)

    Sonai, A; Murata, K [Toshiba Research and Development Center, Kawasaki (Japan)

    1993-11-01

    During a single-cell disassembly test of molten carbonate fuel cells having been operated for 90 hours to 5500 hours, correlativity was discovered between decrease in the retained amount of electrolyte due to decrease in pore capacity of electrodes and electrolyte plates and the electrolyte loss. The electrolyte loss amount cannot be explained with the conventional mechanisms, thereby a new model was proposed. The cathode has shown very little change in the capacity change in pores with diameters smaller than 2 {mu}m per unit area. The anode has remained almost constant after 1000 hours, but the electrolyte plates have shown remarkable decrease. Therefore, it is possible to estimate that the electrolyte plates should have been the major cause for the electrolyte loss. The result of measuring the electrolyte loss amount agreed well with that estimated using pore capacity curves. This fact suggests that the electrolyte loss can be explained by a new mechanism that hypothesizes the existence of a largest size of retaining pores that can support carbonates and defines that the electrolyte loss is generated from decrease in the pore capacity. 7 refs., 8 figs., 1 tab.

  8. Gases in molten salts

    CERN Document Server

    Tomkins, RPT

    1991-01-01

    This volume contains tabulated collections and critical evaluations of original data for the solubility of gases in molten salts, gathered from chemical literature through to the end of 1989. Within the volume, material is arranged according to the individual gas. The gases include hydrogen halides, inert gases, oxygen, nitrogen, hydrogen, carbon dioxide, water vapor and halogens. The molten salts consist of single salts, binary mixtures and multicomponent systems. Included also, is a special section on the solubility of gases in molten silicate systems, focussing on slags and fluxes.

  9. Major design issues of molten carbonate fuel cell power generation unit

    Energy Technology Data Exchange (ETDEWEB)

    Chen, T.P.

    1996-04-01

    In addition to the stack, a fuel cell power generation unit requires fuel desulfurization and reforming, fuel and oxidant preheating, process heat removal, waste heat recovery, steam generation, oxidant supply, power conditioning, water supply and treatment, purge gas supply, instrument air supply, and system control. These support facilities add considerable cost and system complexity. Bechtel, as a system integrator of M-C Power`s molten carbonate fuel cell development team, has spent substantial effort to simplify and minimize these supporting facilities to meet cost and reliability goals for commercialization. Similiar to other fuels cells, MCFC faces design challenge of how to comply with codes and standards, achieve high efficiency and part load performance, and meanwhile minimize utility requirements, weight, plot area, and cost. However, MCFC has several unique design issues due to its high operating temperature, use of molten electrolyte, and the requirement of CO2 recycle.

  10. Nitrogen-Doped Carbon for Red Phosphorous Based Anode Materials for Lithium Ion Batteries

    Directory of Open Access Journals (Sweden)

    Jiaoyang Li

    2018-01-01

    Full Text Available Serving as conductive matrix and stress buffer, the carbon matrix plays a pivotal role in enabling red phosphorus to be a promising anode material for high capacity lithium ion batteries and sodium ion batteries. In this paper, nitrogen-doping is proved to effective enhance the interface interaction between carbon and red phosphorus. In detail, the adsorption energy between phosphorus atoms and oxygen-containing functional groups on the carbon is significantly reduced by nitrogen doping, as verified by X-ray photoelectron spectroscopy. The adsorption mechanisms are further revealed on the basis of DFT (the first density functional theory calculations. The RPNC (red phosphorus/nitrogen-doped carbon composite material shows higher cycling stability and higher capacity than that of RPC (red phosphorus/carbon composite anode. After 100 cycles, the RPNC still keeps discharge capacity of 1453 mAh g−1 at the current density of 300 mA g−1 (the discharge capacity of RPC after 100 cycles is 1348 mAh g−1. Even at 1200 mA g−1, the RPNC composite still delivers a capacity of 1178 mAh g−1. This work provides insight information about the interface interactions between composite materials, as well as new technology develops high performance phosphorus based anode materials.

  11. Studies on sulfur poisoning and development of advanced anodic materials for waste-to-energy fuel cells applications

    Science.gov (United States)

    Zaza, Fabio; Paoletti, Claudia; LoPresti, Roberto; Simonetti, Elisabetta; Pasquali, Mauro

    Biomass is the renewable energy source with the most potential penetration in energy market for its positive environmental and socio-economic consequences: biomass live cycles for energy production is carbon neutral; energy crops promote alternative and productive utilizations of rural sites creating new economic opportunities; bioenergy productions promote local energy independence and global energy security defined as availability of energy resource supply. Different technologies are currently available for energy production from biomass, but a key role is played by fuel cells which have both low environmental impacts and high efficiencies. High temperature fuel cells, such as molten carbonate fuel cells (MCFC), are particularly suitable for bioenergy production because it can be directly fed with biogas: in fact, among its principal constituents, methane can be transformed to hydrogen by internal reforming; carbon dioxide is a safe diluent; carbon monoxide is not a poison, but both a fuel, because it can be discharged at the anode, and a hydrogen supplier, because it can produce hydrogen via the water-gas shift reaction. However, the utilization of biomass derived fuels in MCFC presents different problems not yet solved, such as the poisoning of the anode due to byproducts of biofuel chemical processing. The chemical compound with the major negative effects on cell performances is hydrogen sulfide. It reacts with nickel, the main anodic constituent, forming sulfides and blocking catalytic sites for electrode reactions. The aim of this work is to study the hydrogen sulfide effects on MCFC performances for defining the poisoning mechanisms of conventional nickel-based anode, recommending selection criteria of sulfur-tolerant materials, and selecting advanced anodes for MCFC fed with biogas.

  12. Suitability of granular carbon as an anode material for sediment microbial fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Arends, Jan B.A.; Blondeel, Evelyne; Boon, Nico; Verstraete, Willy [Ghent Univ. (Belgium). Faculty of Bioscience Engineering; Tennison, Steve R. [Mast Carbon International Ltd., Basingstoke, Hampshire (United Kingdom)

    2012-08-15

    Purpose: Sediment microbial fuel cells (S-MFCs) are bio-electrochemical devices that are able to oxidize organic matter directly into harvestable electrical power. The flux of organic matter into the sediment is rather low; therefore, other researchers have introduced plants for a continuous supply of organic matter to the anode electrode. Until now only interconnected materials have been considered as anode materials in S-MFCs. Here, granular carbon materials were investigated for their suitability as an anode material in S-MFCs. Materials and methods: Laboratory microcosms with eight different electrode materials (granules, felts and cloths) were examined with controlled organic matter addition under brackish conditions. Current density, organic matter removal and microbial community composition were monitored using 16S rRNA gene PCR followed by denaturing gradient gel electrophoresis (DGGE). The main parameters investigated were the influence of the amount of electrode material applied to the sediment, the size of the granular material and the electrode configuration. Results and discussion: Felt material had an overall superior performance in terms of current density per amount of applied electrode material; felt and granular anode obtained similar current densities (approx. 50-60 mA m{sup -2}), but felt materials required 29 % less material to be applied. Yet, when growing plants, granular carbon is more suited because it is considered to restore, upon disturbance, the electrical connectivity within the anode compartment. Small granules (0.25-0.5 mm) gave the highest current density compared to larger granules (1-5 mm) of the same material. Granules with a rough surface had a better performance compared to smooth granules of the same size. The different granular materials lead to a selection of distinct microbial communities for each material, as shown by DGGE. Conclusions: Granular carbon is suitable as an anode material for S-MFCs. This opens the possibility

  13. Molten salt reactors. Synthesis of studies realized between 1973 and 1983. Carbon-materials file

    International Nuclear Information System (INIS)

    1983-03-01

    The study of a molten salt fueled reactor requires a thorough examination of carbon containing materials for moderator, reflectors and structural materials. Are examined: texture, structure, physical and mechanical properties, chemical purity, neutron irradiation, salt-graphite and salt-lead interactions for different types of graphite. [fr

  14. Aerogel and xerogel composites for use as carbon anodes

    Science.gov (United States)

    Cooper, John F [Oakland, CA; Tillotson, Thomas M [Tracy, CA; Hrubesh, Lawrence W [Pleasanton, CA

    2008-08-12

    Disclosed herein are aerogel and xerogel composite materials suitable for use as anodes in fuel cells and batteries. Precursors to the aerogel and xerogel compounds are infused with inorganic polymeric materials or carbon particles and then gelled. The gels are then pyrolyzed to form composites with internal structural support.

  15. Stable cyclic performance of nickel oxide–carbon composite anode for lithium-ion batteries

    International Nuclear Information System (INIS)

    Susantyoko, Rahmat Agung; Wang, Xinghui; Fan, Yu; Xiao, Qizhen; Fitzgerald, Eugene; Pey, Kin Leong; Zhang, Qing

    2014-01-01

    Nickel oxide (NiO) directly grown on nickel foam is regarded as a promising lithium ion battery anode material which shows good cyclic and rate performances with a theoretical specific capacity of 718 mA h g −1 . In this study, we demonstrated a carbon-incorporated NiO anode (NiO–C) with a capacity per unit area of 2.11 mA h cm −2 and 1.76 mA h cm −2 at 0.2 C and 0.5 C rates, respectively, fabricated by thermal oxidation of carbon coated nickel foam. The specific capacity of our NiO–C composite samples at 0.5 C rate is found to be typically 389.16 mA h g −1 , with a stable cyclic performance up to more than 100 cycles. This remarkable performance is apparently superior to the control samples of pure NiO samples. The improved performance is contributed to carbon incorporation which serves as a fluent channel for electrons and a flexible network preventing NiO nanostructures from structural deformation during charge and discharge processes. The advantage of using our approach is the easy preparation of the NiO–C composite using a simple two-step process: chemical vapor deposition of ethanol and annealing in air. - Highlights: • We demonstrated a directly grown NiO–C anode on nickel foam substrate. • NiO–C anode was made using simple processes: CVD of ethanol and annealing in air. • The NiO–C anode has a stable cycle life up to 102 cycles. • It has an acceptable areal capacity (1.76 mA h cm −2 at 0.5 C rate) for practical use. • Carbon provides electrons path and buffering matrix preventing NiO pulverization

  16. High Surface Iridium Anodes for Molten Oxide Electrolysis, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Processing of lunar regolith into oxygen for habitat and propulsion is needed to support future space missions. Direct electrochemical reduction of molten regolith...

  17. The Incorporation of Lithium Alloying Metals into Carbon Matrices for Lithium Ion Battery Anodes

    Science.gov (United States)

    Hays, Kevin A.

    arsenic particles that were synthesized on melt away carbon nanotubes by akalide reduction. The performance of these anodes proved sensitive to electrolyte composition, which was significantly improved by using fluorinated ethylene carbonate. Additionally, further gains in capacity retention can be made by limiting the loading voltage to 0.75 V vs lithium metal. The arsenic and melt away carbon nanotube composite was found to have excellent cycle life and capacity at high mass loading (80% arsenic) when the nanoparticles were directly synthesized on the melt away carbon nanotubes. Gallium arsenide is well known for its semiconducting properties, but its performance as in Li-ion battery anodes is first reported here. Gallium is a metal with a low melting point that has been touted as a possible self-healing material for lithium ion anodes. Alone, gallium proves to be unstable as a lithium ion battery anode, but when synthesized as gallium arsenide nanoparticles and mixed with melt away carbon nanotubes it can charge and discharge in a battery 100 times with approximately twice the capacity of graphite anodes. This first study of gallium arsenide shows dramatic cycle life improvements by using nanoscale rather that micron size gallium arsenide.

  18. Advanced LiTi2(PO4)3@N-doped carbon anode for aqueous lithium ion batteries

    International Nuclear Information System (INIS)

    He, Zhangxing; Jiang, Yingqiao; Meng, Wei; Zhu, Jing; Liu, Yang; Dai, Lei; Wang, Ling

    2016-01-01

    Highlights: • LiTi 2 (PO 4 ) 3 @N-doped carbon anode was prepared by in-situ coating approach for aqueous lithium ion batteries. • The well-proportioned N-doped carbon layer and loose nanoporous structure was obtained using urea as nitrogen source and pore former. • LiTi 2 (PO 4 ) 3 @N-doped carbon demonstrates excellent rate performance and good cycling stability. - Abstract: In this paper, LiTi 2 (PO 4 ) 3 @N-doped carbon anode has been synthesized by in situ carbon coating approach. The well-proportioned N-doped carbon layer and loose nanoporous structure was obtained by using urea as nitrogen source and pore former. LiTi 2 (PO 4 ) 3 @N-doped carbon as anode demonstrates much better rate capability than LiTi 2 (PO 4 ) 3 @carbon in ALIBs. The optimized anode delivers the discharge capacity of 93.7 mAh g −1 and 74.2 mAh g −1 at rates of 10C and 20C, 22.5 mAh g −1 and 50.0 mAh g −1 larger than that of LiTi 2 (PO 4 ) 3 @carbon. Moreover, LiTi 2 (PO 4 ) 3 @N-doped carbon exhibits excellent cycling performance with capacity retention of 84.3% at 5C after 1000 cycles. As verified, the well-proportioned N-doped carbon layer could reduce charge transfer resistance and improve electrical conductivity. The loose nanoporous structure could shorten pathway and facilitate diffusion for Li ion. Therefore, LiTi 2 (PO 4 ) 3 @N-doped carbon gets the superior electrochemical properties benefiting from those two characteristics.

  19. Integrated carbon nanospheres arrays as anode materials for boosted sodium ion storage

    Directory of Open Access Journals (Sweden)

    Wangjia Tang

    2018-01-01

    Full Text Available Developing cost-effective advanced carbon anode is critical for innovation of sodium ion batteries. Herein, we develop a powerful combined method for rational synthesis of free-standing binder-free carbon nanospheres arrays via chemical bath plus hydrothermal process. Impressively, carbon spheres with diameters of 150–250 nm are randomly interconnected with each other forming highly porous arrays. Positive advantages including large porosity, high surface and strong mechanical stability are combined in the carbon nanospheres arrays. The obtained carbon nanospheres arrays are tested as anode material for sodium ion batteries (SIBs and deliver a high reversible capacity of 102 mAh g−1 and keep a capacity retention of 95% after 100 cycles at a current density of 0.25 A g−1 and good rate performance (65 mAh g−1 at a high current density of 2 A g−1. The good electrochemical performance is attributed to the stable porous nanosphere structure with fast ion/electron transfer characteristics.

  20. The mechanisms for filling carbon nanotubes with molten salts: carbon nanotubes as energy landscape filters

    International Nuclear Information System (INIS)

    Bishop, Clare L; Wilson, Mark

    2009-01-01

    The mechanisms for filling carbon nanotubes with molten salts are investigated using molecular dynamics computer simulation. Inorganic nanotubular structures, whose morphologies can be rationalized in terms of the folding, or the removal of sections from, planes of square nets are found to form. The formation mechanisms are found to follow a 'chain-by-chain' motif in which the structures build systematically from charge neutral M-X-M-Xc chains. The formation mechanisms are rationalized in terms of the ion-ion interactions (intra-chain and inter-chain terms). In addition, the mechanisms of filling are discussed in terms of a 'hopping' between basins on the underlying energy landscape. The role of the carbon nanotube as an energy landscape filter is discussed.

  1. Electrical transport through single-wall carbon nanotube-anodic aluminum oxide-aluminum heterostructures

    International Nuclear Information System (INIS)

    Kukkola, Jarmo; Rautio, Aatto; Sala, Giovanni; Pino, Flavio; Toth, Geza; Leino, Anne-Riikka; Maeklin, Jani; Jantunen, Heli; Uusimaeki, Antti; Kordas, Krisztian; Gracia, Eduardo; Terrones, Mauricio; Shchukarev, Andrey; Mikkola, Jyri-Pekka

    2010-01-01

    Aluminum foils were anodized in sulfuric acid solution to form thick porous anodic aluminum oxide (AAO) films of thickness ∼6 μm. Electrodes of carboxyl-functionalized single-wall carbon nanotube (SWCNT) thin films were inkjet printed on the anodic oxide layer and the electrical characteristics of the as-obtained SWCNT-AAO-Al structures were studied. Nonlinear current-voltage transport and strong temperature dependence of conduction through the structure was measured. The microstructure and chemical composition of the anodic oxide layer was analyzed using transmission and scanning electron microscopy as well as x-ray photoelectron spectroscopy. Schottky emission at the SWCNT-AAO and AAO-Al interfaces allowed by impurity states in the anodic aluminum oxide film together with ionic surface conduction on the pore walls of AAO gives a reasonable explanation for the measured electrical conduction. Calcined AAO is proposed as a dielectric material for SWCNT-field effect transistors.

  2. Influence of heat-treatment on lithium ion anode properties of mesoporous carbons with nanosheet-like walls

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Fanyan [College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China); Hou, Zhaohui, E-mail: zhqh96@163.com [College of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006 (China); He, Binhong [College of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006 (China); Ge, Chongyong; Cao, Jianguo [College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China); Kuang, Yafei, E-mail: yafeik@163.com [College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China)

    2012-08-15

    Highlights: ► Mesoporous carbons possess unique nanosheet-like pore walls which can be changed by heat treatment. ► Lithium ion anode properties of mesoporous carbons could be influenced by the nanosheet-like walls. ► Mesoporous carbons with nanosheet-like walls exhibit enhanced electrochemical properties LIBs. -- Abstract: Mesoporous carbons (MCs) with nanosheet-like walls have been prepared as electrodes for lithium-ion batteries by a simple one-step infiltrating method under the action of capillary flow. The influence of heat treatment temperature on the surface topography, pore/phase structure and anode performances of as-prepared materials has been investigated. The results reveal that melted liquid-crystal polycyclic aromatic hydrocarbons could be anchored on liquid/silica interfaces by molecule engineering. After carbonization, the nanosheets are formed as the pore walls of MCs and are perpendicular to the long axis of pores. The anode properties demonstrate that C-1200 displays higher reversible capacitance than those treated in higher temperature. The rate performances of C-1200 and C-1800 are similar and more excellent than that of C-2400. These improved lithium ion anode properties could be attributed to the nanosheet-like walls of MCs which can be influenced by the heat treatment temperature.

  3. Forecasting approach of electrochemical valorisation of CO2 in alkali molten carbonates

    International Nuclear Information System (INIS)

    Chery, Deborah

    2015-01-01

    Carbon Dioxide is a greenhouse which can be valorised by means of electrochemical valorisation into carbon monoxide. The main goals of the thesis consist in the theoretical determination of the conductive conditions leading to this electrochemical valorisation in alkali molten carbonates along with the study of the feasibility of this electrochemical reduction in binary and ternary eutectics under experimental condition. CO 2 solubility has been determined by manometric measure and increase along with the temperature. CO 2 electrochemical experimental feasibility into CO in eutectics on gold plate electrode and graphite carbon has been proved by cyclic volt-amperometry for temperatures exceeding 550 C, without gold plate electrode pretreatment and with gold plate pretreatment by an pre-electrolysis at potential slightly negative as the CO 2 reduction potential. A global approach of reactional mechanisms implied in CO 2 reduction is proposed. (author)

  4. Carbon-Coated SnO2 Nanorod Array for Lithium-Ion Battery Anode Material

    Directory of Open Access Journals (Sweden)

    Ji Xiaoxu

    2010-01-01

    Full Text Available Abstract Carbon-coated SnO2 nanorod array directly grown on the substrate has been prepared by a two-step hydrothermal method for anode material of lithium-ion batteries (LIBs. The structural, morphological and electrochemical properties were investigated by means of X-ray diffraction (XRD, scanning electron microscopy (SEM, transmission electron microscopy (TEM and electrochemical measurement. When used as anodes for LIBs with high current density, as-obtained array reveals excellent cycling stability and rate capability. This straightforward approach can be extended to the synthesis of other carbon-coated metal oxides for application of LIBs.

  5. Electrochemical properties of carbon nanocoils and hollow graphite fibers as anodes for rechargeable lithium ion batteries

    International Nuclear Information System (INIS)

    Wang, Liyong; Liu, Zhanjun; Guo, Quangui; Wang, Guizhen; Yang, Jinhua; Li, Peng; Wang, Xianglei; Liu, Lang

    2016-01-01

    Carbon nanocoils (CNCs) have been used as anode materials for preparation of lithium ion batteries. As pure carbon material without any chemical modification, the graphitized CNCs anode exhibited larger capacities with good Coulombic efficiency, a higher rate capability, and better reversibility than the hollow graphite fibers (HGFs) anode. The excellent performance of the CNCs was possibly ascribed to the special structure and the high degree of graphitization. As a result, the CNCs anode exhibited high reversible capacity of 385.5 mA h g"−"1 at 50 mA g"−"1, 104.7% reversible capacity retention after 105 cycles, and superior reversible capability of 177.4 mA h g"−"1 at 1 A g"−"1 after 100 cycles. This result indicated that CNCs could be an attractive choice as anode material for high-energy density and high-power lithium-ion batteries.

  6. Three-dimensional core-shell Fe_2O_3 @ carbon/carbon cloth as binder-free anode for the high-performance lithium-ion batteries

    International Nuclear Information System (INIS)

    Wang, Xiaohua; Zhang, Miao; Liu, Enzuo; He, Fang; Shi, Chunsheng; He, Chunnian; Li, Jiajun; Zhao, Naiqin

    2016-01-01

    Highlights: • The 3D core-shell Fe_2O_3@C/CC structure is fabricated by simple hydrothermal route. • The composite connected 3D carbon networks consist of carbon cloth, Fe_2O_3 nanorods and outer carbon layer. • The Fe_2O_3@C/CC used as binder-free anode in LIBs, demonstrates excellent performances. - Abstract: A facile and scalable strategy is developed to fabricate three dimensional core-shell Fe_2O_3 @ carbon/carbon cloth structure by simple hydrothermal route as binder-free lithium-ion battery anode. In the unique structure, carbon coated Fe_2O_3 nanorods uniformly disperse on carbon cloth which forms the conductive carbon network. The hierarchical porous Fe_2O_3 nanorods in situ grown on the carbon cloth can effectively shorten the transfer paths of lithium ions and reduce the contact resistance. The carbon coating significantly inhibits pulverization of active materials during the repeated Li-ion insertion/extraction, as well as the direct exposure of Fe_2O_3 to the electrolyte. Benefiting from the structural integrity and flexibility, the nanocomposites used as binder-free anode for lithium-ion batteries, demonstrate high reversible capacity and excellent cyclability. Moreover, this kind of material represents an alternative promising candidate for flexible, cost-effective, and binder-free energy storage devices.

  7. Facile synthesis of carbon/MoO 3 nanocomposites as stable battery anodes

    KAUST Repository

    Ding, Jiang

    2017-03-09

    Pristine MoO3 is a potential anode material for lithium-ion batteries (LIBs), due to its high specific capacity (1117 mA h g−1); it suffers, however, from poor cyclability, resulting from a low conductivity and large volume changes during lithiation/delithiation process. Here we adopt a facile two-step method in which pristine bulk MoO3 is first converted into MoO3 nanorods (MoO3 NR) through mechanical grinding, to buffer the continuous volume changes, and then coated with amorphous carbon through simple stirring and heating, to provide high electronic and ionic conductivities. Electrochemical tests reveal that the carbon-coated MoO3 nanorods (C-MoO3 NRs) exhibit outstanding specific capacity (856 mA h g−1 after 110 cycles at a current density of 0.1 C); remarkable cycle life, among the best reported for carbon-based MoO3 nanostructures (485 mA h g−1 after 300 cycles at 0.5 C and 373 mA h g−1 after 400 cycles at 0.75 C); and greatly improved capacity retention (up to 90.4% after various C-rates) compared to bulk MoO3. We confirm the versatility of the C-MoO3 NR anodes by preparing flexible batteries that display stable performance, even in bent state. This simple approach toward C-MoO3 NR anodes proceeds without rigorous chemical synthesis or extremely high temperatures, making it a scalable solution to prepare high-capacity anodes for next-generation LIBs.

  8. An activated microporous carbon prepared from phenol-melamine-formaldehyde resin for lithium ion battery anode

    International Nuclear Information System (INIS)

    Zhu, Yinhai; Xiang, Xiaoxia; Liu, Enhui; Wu, Yuhu; Xie, Hui; Wu, Zhilian; Tian, Yingying

    2012-01-01

    Highlights: ► Microporous carbon was prepared by chemical activation of phenol-melamine-formaldehyde resin. ► Activation leads to high surface area, well-developed micropores. ► Micropores lead to strong intercalation between carbon and lithium ion. ► Large surface area promotes to improve the lithium storage capacity. -- Abstract: Microporous carbon anode materials were prepared from phenol-melamine-formaldehyde resin by ZnCl 2 and KOH activation. The physicochemical properties of the obtained carbon materials were characterized by scanning electron microscope, X-ray diffraction, Brunauer–Emmett–Teller, and elemental analysis. The electrochemical properties of the microporous carbon as anode materials in lithium ion secondary batteries were evaluated. At a current density of 100 mA g −1 , the carbon without activation shows a first discharge capacity of 515 mAh g −1 . After activation, the capacity improved obviously. The first discharge capacity of the carbon prepared by ZnCl 2 and KOH activation was 1010 and 2085 mAh g −1 , respectively. The reversible capacity of the carbon prepared by KOH activation was still as high as 717 mAh g −1 after 20 cycles, which was much better than that activated by ZnCl 2 . These results demonstrated that it may be a promising candidate as an anode material for lithium ion secondary batteries.

  9. Hard carbon coated nano-Si/graphite composite as a high performance anode for Li-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Sookyung; Li, Xiaolin; Zheng, Jianming; Yan, Pengfei; Cao, Ruiguo; Jung, Hee Joon; Wang, Chong M.; Liu, Jun; Zhang, Jiguang

    2016-08-27

    With the ever increasing demands on Li-ion batteries with higher energy densities, alternative anode with higher reversible capacity is required to replace the conventional graphite anode. Here, we demonstrate a cost-effective hydrothermal-carbonization approach to prepare the hard carbon coated nano-Si/graphite (HC-nSi/G) composite as a high performance anode for Li-ion batteries. In this hierarchical structured composite, the hard carbon coating layer not only provides an efficient pathway for electron transfer, but also alleviates the volume variation of silicon during charge/discharge processes. The HC-nSi/G composite electrode shows excellent electrochemical performances including a high specific capacity of 878.6 mAh g-1 based on the total weight of composite, good rate performance and a decent cycling stability, which is promising for practical applications.

  10. MnO-carbon hybrid nanofiber composites as superior anode materials for lithium-ion batteries

    International Nuclear Information System (INIS)

    Wang, Jian-Gan; Yang, Ying; Huang, Zheng-Hong; Kang, Feiyu

    2015-01-01

    MnO-carbon hybrid nanofiber composites are fabricated by electrospinning polyimide/manganese acetylacetonate precursor and a subsequent carbonization process. The composition, phase structure and morphology of the composites are characterized by scanning and transmission electron microscopy, X-ray diffraction and thermogravimetric analysis. The results indicate that the composites exhibit good nanofibrous morphology with MnO nanoparticles uniformly encapsulated by carbon nanofibers. The hybrid nanofiber composites are used directly as freestanding anodes for lithium-ion batteries to evaluate their electrochemical properties. It is found that the optimized MnO-carbon nanofiber composite can deliver a high reversible capacity of 663 mAh g −1 , along with excellent cycling stability and good rate capability. The superior performance enables the composites to be promising candidates as an anode alternative for high-performance lithium-ion batteries

  11. OPTIMIZATION OF THE CATHODE LONG-TERM STABILITY IN MOLTEN CARBONATE FUEL CELLS: EXPERIMENTAL STUDY AND MATHEMATICAL MODELING

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Ralph E. White; Dr. Branko N. Popov

    2002-04-01

    The dissolution of NiO cathodes during cell operation is a limiting factor to the successful commercialization of molten carbonate fuel cells (MCFCs). Lithium cobalt oxide coating onto the porous nickel electrode has been adopted to modify the conventional MCFC cathode which is believed to increase the stability of the cathodes in the carbonate melt. The material used for surface modification should possess thermodynamic stability in the molten carbonate and also should be electro catalytically active for MCFC reactions. Two approaches have been adopted to get a stable cathode material. First approach is the use of LiNi{sub 0.8}Co{sub 0.2}O{sub 2}, a commercially available lithium battery cathode material and the second is the use of tape cast electrodes prepared from cobalt coated nickel powders. The morphology and the structure of LiNi{sub 0.8}Co{sub 0.2}O{sub 2} and tape cast Co coated nickel powder electrodes were studied using scanning electron microscopy and X-Ray diffraction studies respectively. The electrochemical performance of the two materials was investigated by electrochemical impedance spectroscopy and polarization studies. A three phase homogeneous model was developed to simulate the performance of the molten carbonate fuel cell cathode. The homogeneous model is based on volume averaging of different variables in the three phases over a small volume element. The model gives a good fit to the experimental data. The model has been used to analyze MCFC cathode performance under a wide range of operating conditions.

  12. Computational Evaluation of Amorphous Carbon Coating for Durable Silicon Anodes for Lithium-Ion Batteries

    Science.gov (United States)

    Hwang, Jeongwoon; Ihm, Jisoon; Lee, Kwang-Ryeol; Kim, Seungchul

    2015-01-01

    We investigate the structural, mechanical, and electronic properties of graphite-like amorphous carbon coating on bulky silicon to examine whether it can improve the durability of the silicon anodes of lithium-ion batteries using molecular dynamics simulations and ab-initio electronic structure calculations. Structural models of carbon coating are constructed using molecular dynamics simulations of atomic carbon deposition with low incident energies (1–16 eV). As the incident energy decreases, the ratio of sp2 carbons increases, that of sp3 decreases, and the carbon films become more porous. The films prepared with very low incident energy contain lithium-ion conducting channels. Also, those films are electrically conductive to supplement the poor conductivity of silicon and can restore their structure after large deformation to accommodate the volume change during the operations. As a result of this study, we suggest that graphite-like porous carbon coating on silicon will extend the lifetime of the silicon anodes of lithium-ion batteries. PMID:28347087

  13. Computational Evaluation of Amorphous Carbon Coating for Durable Silicon Anodes for Lithium-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Jeongwoon Hwang

    2015-10-01

    Full Text Available We investigate the structural, mechanical, and electronic properties of graphite-like amorphous carbon coating on bulky silicon to examine whether it can improve the durability of the silicon anodes of lithium-ion batteries using molecular dynamics simulations and ab-initio electronic structure calculations. Structural models of carbon coating are constructed using molecular dynamics simulations of atomic carbon deposition with low incident energies (1–16 eV. As the incident energy decreases, the ratio of sp2 carbons increases, that of sp3 decreases, and the carbon films become more porous. The films prepared with very low incident energy contain lithium-ion conducting channels. Also, those films are electrically conductive to supplement the poor conductivity of silicon and can restore their structure after large deformation to accommodate the volume change during the operations. As a result of this study, we suggest that graphite-like porous carbon coating on silicon will extend the lifetime of the silicon anodes of lithium-ion batteries.

  14. OPTIMIZATION OF THE CATHODE LONG-TERM STABILITY IN MOLTEN CARBONATE FUEL CELLS: EXPERIMENTAL STUDY AND MATHEMATICAL MODELING

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Ralph E. White; Dr. Branko N. Popov

    2001-10-01

    The dissolution of NiO cathodes during cell operation is a limiting factor to the successful commercialization of molten carbonate fuel cells (MCFCs). Lithium cobalt oxide coating onto the porous nickel electrode has been adopted to modify the conventional MCFC cathode which is believed to increase the stability of the cathodes in the carbonate melt. The material used for surface modification should possess thermodynamic stability in the molten carbonate and also should be electro catalytically active for MCFC reactions. Lithium Cobalt oxide was coated on Ni cathode by a sol-gel coating. The morphology and the LiCoO{sub 2} formation of LiCoO{sub 2} coated NiO was studied using scanning electron microscopy and X-Ray diffraction studies respectively. The electrochemical performance lithium cobalt oxide coated NiO cathodes were investigated with open circuit potential measurement and current-potential polarization studies. These results were compared to that of bare NiO. Dissolution of nickel into the molten carbonate melt was less in case of lithium cobalt oxide coated nickel cathodes. LiCoO{sub 2} coated on the surface prevents the dissolution of Ni in the melt and thereby stabilizes the cathode. Finally, lithium cobalt oxide coated nickel shows similar polarization characteristics as nickel oxide. Conventional theoretical models for the molten carbonate fuel cell cathode are based on the thin film agglomerate model. The principal deficiency of the agglomerate model, apart from the simplified pore structure assumed, is the lack of measured values for film thickness and agglomerate radius. Both these parameters cannot be estimated appropriately. Attempts to estimate the thickness of the film vary by two orders of magnitude. To avoid these problems a new three phase homogeneous model has been developed using the volume averaging technique. The model considers the potential and current variation in both liquid and solid phases. Using this approach, volume averaged

  15. Effects of coal-derived trace species on the performance of molten carbonate fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Pigeaud, A.

    1991-10-01

    The overall objective of the present study was to determine in detail the interaction effects of 10 simultaneously present, coal-gas contaminants, both on each other and on components of the Carbonate Fuel Cell. The primary goal was to assess underlying chemistries and reaction mechanisms which may cause decay in fuel cell performance or endurance as a result of both physics-chemical and/or mechanical interactions with the cell components and internal fuel cell parts. It was found, both from theory and cell test evidence, that trace contaminant interactions may occur with: Fuel-cell Electrodes (e.g., in this study with the Ni-anode), Lithium/Potassium Carbonate Electrolyte, Nickel and SS-Hardware, and by Mechanical Obstruction of Gas Flow in the Anode Plenum.

  16. Anodic aluminium oxide membranes used for the growth of carbon nanotubes.

    Science.gov (United States)

    López, Vicente; Morant, Carmen; Márquez, Francisco; Zamora, Félix; Elizalde, Eduardo

    2009-11-01

    The suitability of anodic aluminum oxide (AAO) membranes as template supported on Si substrates for obtaining organized iron catalyst for carbon nanotube (CNT) growth has been investigated. The iron catalyst was confined in the holes of the AAO membrane. CVD synthesis with ethylene as carbon source led to a variety of carbon structures (nanotubes, helices, bamboo-like, etc). In absence of AAO membrane the catalyst was homogeneously distributed on the Si surface producing a high density of micron-length CNTs.

  17. Molten salt battery having inorganic paper separator

    Science.gov (United States)

    Walker, Jr., Robert D.

    1977-01-01

    A high temperature secondary battery comprises an anode containing lithium, a cathode containing a chalcogen or chalcogenide, a molten salt electrolyte containing lithium ions, and a separator comprising a porous sheet comprising a homogenous mixture of 2-20 wt.% chrysotile asbestos fibers and the remainder inorganic material non-reactive with the battery components. The non-reactive material is present as fibers, powder, or a fiber-powder mixture.

  18. Improving the Tribological Properties of Spark-Anodized Titanium by Magnetron Sputtered Diamond-Like Carbon

    OpenAIRE

    Zhaoxiang Chen; Xipeng Ren; Limei Ren; Tengchao Wang; Xiaowen Qi; Yulin Yang

    2018-01-01

    Spark-anodization of titanium can produce adherent and wear-resistant TiO2 film on the surface, but the spark-anodized titanium has lots of surface micro-pores, resulting in an unstable and high friction coefficient against many counterparts. In this study, the diamond-like carbon (DLC) was introduced into the micro-pores of spark-anodized titanium by the magnetron sputtering technique and a TiO2/DLC composite coating was fabricated. The microstructure and tribological properties of TiO2/DLC ...

  19. A facile strategy to construct binder-free flexible carbonate composite anode at low temperature with high performances for lithium-ion batteries

    International Nuclear Information System (INIS)

    Shi, Shaojun; Zhang, Ming; Deng, Tingting; Wang, Ting; Yang, Gang

    2017-01-01

    Graphical abstract: The schematic illustration of the strategy for preparations and the mechanism for the stability of structure Display Omitted -- Highlights: •A facile strategy is applied to construct flexible carbonate composite anode. •Carbon nano-fiber matrix serves as fast charge channel and efficient buffer. •High specific capacity of 958 mAh g −1 at 100 mA g −1 is obtained. •After 200 cycles at 1 A g −1 , there is not obvious capacity decline. •The mechanism for stress release is further analyzed. -- Abstract: High temperature is usually necessary for carbon modification or electrospinning to obtain flexible anode with excellent conductivity and stability. However, due to the unstable instinct of carbonate, it’s hard to obtain carbonate when any of the synthesis process undergoes high temperature treatment. Thus, a facile strategy is applied to construct binder-free flexible carbonate composite anode at low temperature with high electrochemical performances. The carbon nano-fiber matrix is first synthesized through electrospinning followed by a facile solvothermal process to in-situ grow carbonate on carbon nano-fibers to form a well combinative flexible anode. The carbon nano-fiber matrix serves not only as a fast channel for charge transfer, but also as an efficient buffer to release the stress resulting from the hysteresis of lithiation for carbonate particles during repeated charge/discharge cycles. Owing to the synergistic effect of carbon nano-fiber and the carbonate, the flexible anode exhibits high specific capacity of 958 mAh g −1 . And after 200 cycles at 1 A g −1 , no obvious capacity decline. The reaction mechanism for stress release is also well analyzed to display the merit of our strategy. It is considered as one of the most promising way to get binder-free flexible carbonate anode with remarkable properties.

  20. Carbon dioxide as a green carbon source for the synthesis of carbon cages encapsulating porous silicon as high performance lithium-ion battery anodes.

    Science.gov (United States)

    Zhang, Yaguang; Du, Ning; Chen, Yifan; Lin, Yangfan; Jiang, Jinwei; He, Yuanhong; Lei, Yu; Yang, Deren

    2018-03-28

    Si/C composite is one of the most promising candidate materials for next-generation lithium-ion battery anodes. Herein, we demonstrate the novel structure of carbon cages encapsulating porous Si synthesized by the reaction between magnesium silicide (Mg 2 Si) and carbon dioxide (CO 2 ) and subsequent acid washing. Benefitting from the in situ deposition through magnesiothermic reduction of CO 2 , the carbon cage seals the inner Si completely and shows higher graphitization than that obtained from the decomposition of acetylene. After removing MgO, pores are created, which can accommodate the volume change of the Si anode during the charge/discharge process. As the anode material for lithium-ion batteries, the porous Si/C electrode shows a charge capacity of ∼1124 mA h g -1 after 100 cycles with 86.4% capacity retention at the current density of 0.4 A g -1 . When the current density increases to 1.6 and 3.2 A g -1 , the capacity can still be maintained at ∼860 and ∼460 mA h g -1 , respectively. The prominent cycling and rate performance is contributed by the built-in space for Si expansion, static carbon cages that prevent penetration of electrolyte and stabilize the solid electrolyte interface (SEI) outside, and fast charge transport by the novel structure.

  1. Materials testing for molten carbonate fuel cells

    International Nuclear Information System (INIS)

    Di Mario, F.; Frangini, S.

    1995-01-01

    Unlike conventional generation systems fuel cells use an electrochemical reaction between a fossil fuel and an oxidant to produce electricity through a flame less combustion process. As a result, fuel cells offer interesting technical and operating advantages in terms of conversion efficiencies and environmental benefits due to very low pollutant emissions. Among the different kinds of fuel cells the molten carbonate fuel cells are currently being developed for building compact power generation plants to serve mainly in congested urban areas in virtue of their higher efficiency capabilities at either partial and full loads, good response to power peak loads, fuel flexibility, modularity and, potentially, cost-effectiveness. Starting from an analysis of the most important degradative aspects of the corrosion of the separator plate, the main purpose of this communication is to present the state of the technology in the field of corrosion control of the separator plate in order to extend the useful lifetime of the construction materials to the project goal of 40,000 hours

  2. Electrochemical reduction of actinides oxides in molten salts

    International Nuclear Information System (INIS)

    Claux, B.

    2011-01-01

    Reactive metals are currently produced from their oxide by multiple steps reduction techniques. A one step route from the oxide to the metal has been suggested for metallic titanium production by electrolysis in high temperature molten chloride salts. In the so-called FFC process, titanium oxide is electrochemically reduced at the cathode, generating O 2- ions, which are converted on a graphite anode into carbon oxide or dioxide. After this process, the spent salt can in principle be reused for several batches which is particularly attractive for a nuclear application in terms of waste minimization. In this work, the electrochemical reduction process of cerium oxide (IV) is studied in CaCl 2 and CaCl 2 -KCl melts to understand the oxide reduction mechanism. Cerium is used as a chemical analogue of actinides. Electrolysis on 10 grams of cerium oxide are made to find optimal conditions for the conversion of actinides oxides into metals. The scale-up to hundred grams of oxide is also discussed. (author) [fr

  3. Use of Carbon Mesh Anodes and the Effect of Different Pretreatment Methods on Power Production in Microbial Fuel Cells

    KAUST Repository

    Wang, Xin

    2009-09-01

    Flat electrodes are useful in microbial fuel cells (MFCs) as close electrode spacing improves power generation. Carbon cloth and carbon paper materials typically used in hydrogen fuel cells, however, are prohibitively expensive for use in MFCs. An inexpensive carbon mesh material was examined here as a substantially less expensive alternative to these materials for the anode in an MFC. Pretreatment of the carbon mesh was needed to ensure adequate MFC performance. Heating the carbon mesh in a muffle furnace (450°C for 30 min) resulted in a maximum power density of 922 mW/m2 (46 W/m3) with this heat-treated anode, which was 3% more power than that produced using a mesh anode cleaned with acetone (893 mW/m2; 45 W/m3). This power density with heating was only 7% less than that achieved with carbon cloth treated by a high temperature ammonia gas process (988 mW/m2; 49 W/m3). When the carbon mesh was treated by the ammonia gas process, powerincreased to 1015 mW/m2 (51 W/m3). Analysis of the cleaned or heated surfaces showed these processes decreased atomic O/C ratio, indicating removal of contaminants that interfered with charge transfer. Ammonia gas treatment also increased the atomic N/C ratio, suggesting that this process produced nitrogen related functional groups that facilitated electron transfer. These results show that low cost heat-treated carbon mesh materials can be used as the anode in an MFC, providing good performance and even exceeding performance of carbon cloth anodes. © 2009 American Chemical Society.

  4. Liquid-phase plasma synthesis of silicon quantum dots embedded in carbon matrix for lithium battery anodes

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Ying [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou (China); College of Chemistry and Chemical Engineering, Bohai University, Jinzhou 121000 (China); Yu, Hang; Li, Haitao; Ming, Hai; Pan, Keming; Huang, Hui [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou (China); Liu, Yang, E-mail: yangl@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou (China); Kang, Zhenhui, E-mail: zhkang@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou (China)

    2013-10-15

    Graphical abstract: - Highlights: • Silicon quantum dots embedded in carbon matrix (SiQDs/C) were fabricated. • SiQDs/C exhibits excellent battery performance as anode materials with high specific capacity. • The good performance was attributed to the marriage of small sized SiQDs and carbon. - Abstract: Silicon quantum dots embedded in carbon matrix (SiQDs/C) nanocomposites were prepared by a novel liquid-phase plasma assisted synthetic process. The SiQDs/C nanocomposites were demonstrated to show high specific capacity, good cycling life and high coulmbic efficiency as anode materials for lithium-ion battery.

  5. Liquid-phase plasma synthesis of silicon quantum dots embedded in carbon matrix for lithium battery anodes

    International Nuclear Information System (INIS)

    Wei, Ying; Yu, Hang; Li, Haitao; Ming, Hai; Pan, Keming; Huang, Hui; Liu, Yang; Kang, Zhenhui

    2013-01-01

    Graphical abstract: - Highlights: • Silicon quantum dots embedded in carbon matrix (SiQDs/C) were fabricated. • SiQDs/C exhibits excellent battery performance as anode materials with high specific capacity. • The good performance was attributed to the marriage of small sized SiQDs and carbon. - Abstract: Silicon quantum dots embedded in carbon matrix (SiQDs/C) nanocomposites were prepared by a novel liquid-phase plasma assisted synthetic process. The SiQDs/C nanocomposites were demonstrated to show high specific capacity, good cycling life and high coulmbic efficiency as anode materials for lithium-ion battery

  6. Crystalline and Amorphous Phosphorus – Carbon Nanotube Composites as Promising Anodes for Lithium-Ion Batteries

    KAUST Repository

    Smajic, Jasmin

    2016-05-04

    Battery research has been going full steam and with that the search for alternative anodes. Among many proposed electrode materials, little attention has been given to phosphorus. Phosphorus boasts the third highest gravimetric charge capacity and the highest volumetric charge capacity of all elements. Because of that, it would be an attractive battery anode material were it not for its poor cyclability with significant capacity loss immediately after the first cycle. This is known to be the consequence of considerable volume changes of phosphorus during charge/discharge cycles. In this work, we propose circumventing this issue by mixing amorphous red phosphorus with carbon nanotubes. By employing a non-destructive sublimation-deposition method, we have synthesized composites where the synergetic effect between phosphorus and carbon nanotubes allow for an improvement in the electrochemical performance of battery anodes. In fact, it has been shown that carbon nanotubes can act as an effective buffer to phosphorus volumetric expansions and contractions during charging and discharging of the half-cells [1]. By modifying the synthesis parameters, we have also been able to change the degree of crystallinity of the phosphorus matrix in the composites. In fact, the less common phase of red phosphorus, named fibrous phosphorus, was obtained, and that explains some of the varying electrochemical performances observed in the composites. Overall, it is found that a higher surface area of amorphous phosphorus allows for a better anode material when using single-walled carbon nanotubes as fillers.

  7. Molten salt oxidation of organic hazardous waste with high salt content.

    Science.gov (United States)

    Lin, Chengqian; Chi, Yong; Jin, Yuqi; Jiang, Xuguang; Buekens, Alfons; Zhang, Qi; Chen, Jian

    2018-02-01

    Organic hazardous waste often contains some salt, owing to the widespread use of alkali salts during industrial manufacturing processes. These salts cause complications during the treatment of this type of waste. Molten salt oxidation is a flameless, robust thermal process, with inherent capability of destroying the organic constituents of wastes, while retaining the inorganic ingredients in the molten salt. In the present study, molten salt oxidation is employed for treating a typical organic hazardous waste with a high content of alkali salts. The hazardous waste derives from the production of thiotriazinone. Molten salt oxidation experiments have been conducted using a lab-scale molten salt oxidation reactor, and the emissions of CO, NO, SO 2 , HCl and dioxins are studied. Impacts are investigated from the composition of the molten salts, the types of feeding tube, the temperature of molten carbonates and the air factor. Results show that the waste can be oxidised effectively in a molten salt bath. Temperature of molten carbonates plays the most important role. With the temperature rising from 600 °C to 750 °C, the oxidation efficiency increases from 91.1% to 98.3%. Compared with the temperature, air factor has but a minor effect, as well as the composition of the molten salts and the type of feeding tube. The molten carbonates retain chlorine with an efficiency higher than 99.9% and the emissions of dioxins are below 8 pg TEQ g -1 sample. The present study shows that molten salt oxidation is a promising alternative for the disposal of organic hazardous wastes containing a high salt content.

  8. Macroporous graphitic carbon foam decorated with polydopamine as a high-performance anode for microbial fuel cell

    Science.gov (United States)

    Jiang, Hongmei; Yang, Lu; Deng, Wenfang; Tan, Yueming; Xie, Qingji

    2017-09-01

    Herein, a macroporous graphitic carbon foam (MGCF) electrode decorated with polydopamine (PDA) is used as a high-performance anode for microbial fuel cell (MFC) applications. The MGCF is facilely prepared by pyrolysis of a powder mixture comprising maltose, nickel nitrate, and ammonia chloride, without using solid porous template. The MGCF is coated with PDA by self-polymerization of dopamine in a basic solution. The MGCF can provide a large surface area for bacterial attachment, and PDA coated on the MGCF electrode can further promote bacterial adhesion resulting from the improved hydrophility, so the MGCF-PDA electrode as an anode in a MFC can show ultrahigh bacterial loading capacity. Moreover, the electrochemical oxidation of flavins at the MGCF-PDA electrode is greatly accelerated, so the extracellular electron transfer mediated by flavins is improved. As a result, the MFC equipped with a MGCF-PDA anode can show a maximum power density of 1735 mW cm-2, which is 6.7 times that of a MFC equipped with a commercial carbon felt anode, indicating a promising anode for MFC applications.

  9. Feasibility of multi-walled carbon nanotube probes in AFM anodization lithography

    International Nuclear Information System (INIS)

    Choi, Ji Sun; Bae, Sukjong; Ahn, Sang Jung; Kim, Dal Hyun; Jung, Ki Young; Han, Cheolsu; Chung, Chung Choo; Lee, Haiwon

    2007-01-01

    Multi-walled carbon nanotube (CNT) tips were used in atomic force microscope (AFM) anodization lithography to investigate their advantages over conventional tips. The CNT tip required a larger threshold voltage than the mother silicon tip due to the Schottky barrier at the CNT-Si interface. Current-to-voltage curves distinguished the junction property between CNTs and mother tips. The CNT-platinum tip, which is more conductive than the CNT-silicon tip, showed promising results for AFM anodization lithography. Finally, the nanostructures with high aspect ratio were fabricated using a pulsed bias voltage technique as well as the CNT tip

  10. Medium-chain-length poly-3-hydroxyalkanoates-carbon nanotubes composite anode enhances the performance of microbial fuel cell.

    Science.gov (United States)

    Hindatu, Y; Annuar, M S M; Subramaniam, R; Gumel, A M

    2017-06-01

    Insufficient power generation from a microbial fuel cell (MFC) hampers its progress towards utility-scale development. Electrode modification with biopolymeric materials could potentially address this issue. In this study, medium-chain-length poly-3-hydroxyalkanoates (PHA)/carbon nanotubes (C) composite (CPHA) was successfully applied to modify the surface of carbon cloth (CC) anode in MFC. Characterization of the functional groups on the anodic surface and its morphology was carried out. The CC-CPHA composite anode recorded maximum power density of 254 mW/m 2 , which was 15-53% higher than the MFC operated with CC-C (214 mW/m 2 ) and pristine CC (119 mW/m 2 ) as the anode in a double-chambered MFC operated with Escherichia coli as the biocatalyst. Electrochemical impedance spectroscopy and cyclic voltammetry showed that power enhancement was attributed to better electron transfer capability by the bacteria for the MFC setup with CC-CPHA anode.

  11. Anode property of carbon coated LiFePO4 nanocrystals

    Science.gov (United States)

    Ni, Jiangfeng; Jiang, Jiaxing; Savilov, S. V.; Aldoshin, S. M.

    2016-10-01

    Nanostructured LiFePO4 is appealing cathode material for rechargeable lithium batteries. Herein, however, we report the intriguing anode properties of carbon coated LiFePO4 nanocrystals. In the potential range of 0-3.0 V, the LiFePO4 nanocrystal electrodes afford high reversible capacity of 373 mAhg-1 at a current rate of 0.05 Ag-1 and retains 239 mAhg-1 at a much higher rate of 1.25 Ag-1. In addition, it is capable of sustaining 1000 cycles at 1.25 Ag-1 without any capacity fading. Such superior properties indicate that nanostructured LiFePO4 could also be promising anode for rechargeable battery applications.

  12. Electrochemical properties of Super P carbon black as an anode active material for lithium-ion batteries

    International Nuclear Information System (INIS)

    Gnanamuthu, RM.; Lee, Chang Woo

    2011-01-01

    Highlights: → A novel attempt of Super P carbon black as an anode active material for lithium-ion batteries. → The first discharge capacity was approximately 1256 mAh g -1 and at the end of 20th cycling the capacity was 610 mAh g -1 at 0.1 C rate. → Coulombic efficiency of Super P carbon black electrode was maintained about 84% at the end of cycling. - Abstract: A new approach to investigate upon the electrochemical properties of Super P carbon black anode material is attempted and compared with conventional mesophase pitch-based carbon fibers (MPCFs) anode material for lithium-ion batteries. The prepared Super P carbon black electrodes are characterized using transmission electron microscope (TEM). The assembled 2032-type coin cells are electrochemically characterized by ac impedance spectroscopic and cyclic voltammetric methods. The electrochemical performance of charge and discharge was analyzed using a battery cycler at 0.1 C rate and cut-off potentials of 1.20 and 0.01 V vs. Li/Li + . The electrochemical test illustrates that the discharge capacity corresponding to Li intercalation into the Super P carbon black electrode is higher and coulombic efficiency is maintained approximately 84% at the end of the 20th cycling at room temperature.

  13. Dendrite-free Li metal anode enabled by a 3D free-standing lithiophilic nitrogen-enriched carbon sponge

    Science.gov (United States)

    Hou, Guangmei; Ren, Xiaohua; Ma, Xiaoxin; Zhang, Le; Zhai, Wei; Ai, Qing; Xu, Xiaoyan; Zhang, Lin; Si, Pengchao; Feng, Jinkui; Ding, Fei; Ci, Lijie

    2018-05-01

    Lithium metal is considered as the ultimate anode material for high-energy Li battery systems. However, the commercial application of lithium anode is impeded by issues with safety and low coulombic efficiency induced by Li dendrite growth. Herein, a free-standing three-dimensional nitrogen-enriched graphitic carbon sponge with a high nitrogen content is proposed as a multifunctional current collect for Lithium accommodation. The abundant lithiophilic N-containing functional groups are served as preferred nucleation sites to guide a uniform Li deposition. In addition, the nitrogen-enriched graphitic carbon sponge with a high specific surface area can effectively reduce the local current density. As a result of the synergistic effect, the nitrogen-enriched graphitic carbon sponge electrode realizes a long-term stable cycling without dendrites formation. Notably, the as-obtained composite electrode can deliver an ultra-high specific capacity of ∼3175 mA h g-1. The nitrogen-enriched graphitic carbon sponge might provide innovative insights to design a superior matrix for dendrite-free Li anode.

  14. Monodispersed Carbon-Coated Cubic NiP2 Nanoparticles Anchored on Carbon Nanotubes as Ultra-Long-Life Anodes for Reversible Lithium Storage.

    Science.gov (United States)

    Lou, Peili; Cui, Zhonghui; Jia, Zhiqing; Sun, Jiyang; Tan, Yingbin; Guo, Xiangxin

    2017-04-25

    In search of new electrode materials for lithium-ion batteries, metal phosphides that exhibit desirable properties such as high theoretical capacity, moderate discharge plateau, and relatively low polarization recently have attracted a great deal of attention as anode materials. However, the large volume changes and thus resulting collapse of electrode structure during long-term cycling are still challenges for metal-phosphide-based anodes. Here we report an electrode design strategy to solve these problems. The key to this strategy is to confine the electroactive nanoparticles into flexible conductive hosts (like carbon materials) and meanwhile maintain a monodispersed nature of the electroactive particles within the hosts. Monodispersed carbon-coated cubic NiP 2 nanoparticles anchored on carbon nanotubes (NiP 2 @C-CNTs) as a proof-of-concept were designed and synthesized. Excellent cyclability (more than 1000 cycles) and capacity retention (high capacities of 816 mAh g -1 after 1200 cycles at 1300 mA g -1 and 654.5 mAh g -1 after 1500 cycles at 5000 mA g -1 ) are characterized, which is among the best performance of the NiP 2 anodes and even most of the phosphide-based anodes reported so far. The impressive performance is attributed to the superior structure stability and the enhanced reaction kinetics incurred by our design. Furthermore, a full cell consisting of a NiP 2 @C-CNTs anode and a LiFePO 4 cathode is investigated. It delivers an average discharge capacity of 827 mAh g -1 based on the mass of the NiP 2 anode and exhibits a capacity retention of 80.7% over 200 cycles, with an average output of ∼2.32 V. As a proof-of-concept, these results demonstrate the effectiveness of our strategy on improving the electrode performance. We believe that this strategy for construction of high-performance anodes can be extended to other phase-transformation-type materials, which suffer a large volume change upon lithium insertion/extraction.

  15. OPTIMIZATION OF THE CATHODE LONG TERM STABILITY IN MOLTEN CARBONATE FUEL CELLS: EXPERIMENTAL STUDY AND MATHEMATICAL MODELING

    Energy Technology Data Exchange (ETDEWEB)

    Anand Durairajan; Bala Haran; Branko N. Popov; Ralph E. White

    2000-05-01

    The cathode materials for molten carbonate fuel cells (MCFCs) must have low dissolution rate, high structural strength and good electrical conductivity. Currently available cathodes are made of lithiated NiO which have acceptable structural strength and conductivity. However a study carried out by Orfeld et al. and Shores et al. indicated that the nickel cathodes dissolved, then precipitated and reformed as dendrites across the electrolyte matrix. This results in a decrease in cell utilization and eventually leads to shorting of the cell. The solubility of NiO was found to depend upon the acidity/basicity of the melt (basicity is directly proportional to log P{sub CO2}), carbonate composition, H{sub 2}O partial pressure and temperature. Urushibata et al. found that the dissolution of the cathode is a primary life limiting constraint of MCFCs, particularly in pressurized operation. With currently available NiO cathodes, the goal of 40,000 hours for the lifetime of MCFC appears achievable with cell operation at atmospheric pressure. However, the cell life at 10 atm and higher cell pressures is in the range between 5,000 to 10,000 hours. The overall objective of this research is to develop a superior cathode for MCFC's with improved catalytic ability, enhanced corrosion resistance with low ohmic losses, improved electronic conductivity. We also plan to understand the corrosion processes occurring at the cathode/molten carbonate interface. The following cathode materials will be subjected to detailed electrochemical, performance, structural and corrosion studies. (i) Passivated NiO alloys using chemical treatment with yttrium ion implantation and anodic yttrium molybdate treatment; (ii) Novel composite materials based on NiO and nanosized Ce, Yt, Mo; (iii) Co doped LiNiO{sub 2} LiNiO{sub 2} doped with 10 to 20% Co (LiCo{sub 0.2}NiO{sub 2}) and NiO cathodes; and (iv) CoO as a replacement for NiO. Passivation treatments will inhibit corrosion and increase the

  16. Fundamentals of molten-salt thermal technology

    International Nuclear Information System (INIS)

    1980-08-01

    This book has been published by the Society of Molten-Salt Thermal Technology to publish a part of the achievement of its members. This book is composed of seven chapters. The chapter 1 is Introduction. The chapter 2 explains the physical properties of molten salts, such as thermal behavior, surface tension, viscosity, electrical conductivity and others. The chapter 3 presents the compatibility with construction materials. Corrosion in molten salts, the electrochemical behavior of fluoride ions on carbon electrodes in fluoride melts, the behaviors of hastelloy N and metals in melts are items of this chapter. The equipments and instruments for molten salts are described in chapter 4. The heat transfer in molten salts is discussed in chapter 5. The chapter 6 explains the application of molten salt technology. The molten salt technology can be applied not only to thermal engineering and energy engineering but also to chemical and nuclear engineerings, and the technical fundamentals, current development status, technical problems and the perspective for the future are outlined. The chapter 7 is the summary of this book. The commercialization of molten salt power reactors is discussed at the end of this book. (Kato, T.)

  17. The impact of steam and current density on carbon formation from biomass gasification tar on Ni/YSZ, and Ni/CGO solid oxide fuel cell anodes

    Science.gov (United States)

    Mermelstein, Joshua; Millan, Marcos; Brandon, Nigel

    The combination of solid oxide fuel cells (SOFCs) and biomass gasification has the potential to become an attractive technology for the production of clean renewable energy. However the impact of tars, formed during biomass gasification, on the performance and durability of SOFC anodes has not been well established experimentally. This paper reports an experimental study on the mitigation of carbon formation arising from the exposure of the commonly used Ni/YSZ (yttria stabilized zirconia) and Ni/CGO (gadolinium-doped ceria) SOFC anodes to biomass gasification tars. Carbon formation and cell degradation was reduced through means of steam reforming of the tar over the nickel anode, and partial oxidation of benzene model tar via the transport of oxygen ions to the anode while operating the fuel cell under load. Thermodynamic calculations suggest that a threshold current density of 365 mA cm -2 was required to suppress carbon formation in dry conditions, which was consistent with the results of experiments conducted in this study. The importance of both anode microstructure and composition towards carbon deposition was seen in the comparison of Ni/YSZ and Ni/CGO anodes exposed to the biomass gasification tar. Under steam concentrations greater than the thermodynamic threshold for carbon deposition, Ni/YSZ anodes still exhibited cell degradation, as shown by increased polarization resistances, and carbon formation was seen using SEM imaging. Ni/CGO anodes were found to be more resilient to carbon formation than Ni/YSZ anodes, and displayed increased performance after each subsequent exposure to tar, likely due to continued reforming of condensed tar on the anode.

  18. Recovery of uranium from uranium and lanthanides in LiCl-KCl molten salt by electrowinning including Cd-Li anode

    International Nuclear Information System (INIS)

    Woo, Moon Shik; Kim, Eung Ho

    2005-01-01

    A trans-uranium (TRU) fuel should be manufactured and loaded in transmutation systems in order to transmute the long-lived TRU nuclides into short-lived ones. However, since all of the TRU nuclides are not completely transmuted in one cycle lifetime in transmutation systems, the spent TRU fuel has to be treated to recover the long-lived radionuclides or fuel matrix materials. One concept to manufacture TRU fuel for transmutation is to recover uranium from TRU and molten salt. If this type of fuel is adopted for transmutation, uranium could also be an objective material to be recovered and recycled. Since electrowinning is a promising technology to be employed for the recovery of uranium from fuel materials, some experimental work of electrowinning using anode of Cd-Li alloy was carried out in this study. The basic salt chosen was a mixture of LiCl-KCl which has an eutectic point at 357 .deg. C

  19. Anodic stripping voltammetric determination of silver ion at a carbon paste electrode modified with carbon nanotubes

    International Nuclear Information System (INIS)

    Tashkhourian, J.; Javadi, S.; Ana, F.N.

    2011-01-01

    A carbon paste electrode (CPE) was modified with multi-wall carbon nanotubes and successfully applied to the determination of silver ion by differential pulse anodic stripping voltammetry. Compared to a conventional CPE, a remarkably improved peak current response and sensitivity is observed. The analytical procedure consisted of an open circuit accumulation step for 2 min in -0.4 V, this followed by an anodic potential scan between +0.2 and + 0.6 V to obtain the voltammetric peak. The oxidation peak current is proportional to the concentration of silver ion in the range from 1.0 x 10 -8 to 1.0 x 10 -5 mol L -1 , with a detection limit of 1.8 x 10 -9 mol L -1 after an accumulation time of 120 s. The relative standard deviation for 7 successive determinations of Ag(I) at 0.1 μM concentration is 1.99%. The procedure was validated by determining Ag(I) in natural waters. (author)

  20. Molten salt synthesis of sodium lithium titanium oxide anode material for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Yin, S.Y., E-mail: yshy2004@hotmail.com [College of Environmental and Biological Engineering, Wuhan Technology and Business University, Wuhan 430065 (China); Feng, C.Q. [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry of Education Key Laboratory for Synthesis and Applications of Organic Functional Molecules, Hubei University, Wuhan 430062 (China); Wu, S.J.; Liu, H.L.; Ke, B.Q. [College of Environmental and Biological Engineering, Wuhan Technology and Business University, Wuhan 430065 (China); Zhang, K.L. [College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Chen, D.H. [College of Environmental and Biological Engineering, Wuhan Technology and Business University, Wuhan 430065 (China); Hubei Key Laboratory for Catalysis and Material Science, College of Chemistry and Material Science, South Central University for Nationalities, Wuhan 430074, Hubei (China)

    2015-09-05

    Highlights: • Na{sub 2}Li{sub 2}Ti{sub 6}O{sub 12} has been successfully synthesized via a molten salt route. • Calcination temperature is an important effect on the component and microstructure of the product. • Pure phase Na{sub 2}Li{sub 2}Ti{sub 6}O{sub 12} could be obtained at 700 °C for 2 h. - Abstract: The sodium lithium titanium oxide with composition Na{sub 2}Li{sub 2}Ti{sub 6}O{sub 14} has been synthesized by a molten salt synthesis method using sodium chloride and potassium chloride mixture as a flux medium. Synthetic variables on the synthesis, such as sintering temperature, sintering time and the amount of lithium carbonate, were intensively investigated. Powder X-ray diffraction and scanning electron microscopy images of the reaction products indicates that pure phase sodium lithium titanium oxide has been obtained at 700 °C, and impure phase sodium hexatitanate with whiskers produced at higher temperature due to lithium evaporative losses. The results of cyclic voltammetry and discharge–charge tests demonstrate that the synthesized products prepared at various temperatures exhibited electrochemical diversities due to the difference of the components. And the sample obtained at 700 °C revealed highly reversible insertion and extraction of Li{sup +} and displayed a single potential plateau at around 1.3 V. The product obtained at 700 °C for 2 h exhibits good cycling properties and retains the specific capacity of 62 mAh g{sup −1} after 500 cycles.

  1. Oxidation mechanism and passive behaviour of nickel in molten carbonate

    Energy Technology Data Exchange (ETDEWEB)

    Vossen, J.P.T. (ECN Fossil Fuels, Petten (Netherlands)); Ament, P.C.H.; De Wit, J.H.W. (Div. of Corrosion, Lab. for Maaterials Sceince, Delft Univ. of Technology, Delft (Netherlands))

    1994-07-01

    The oxidation and passivation mechanism and the passive behaviour of nickel in molten carbonate have been investigated with impedance measurements. The oxidation of nickel proceeds according to a dissolution and reprecipitation process. The slowest steps in the reaction sequence are the dissociation reaction of the carbonate and the diffusion of the formed NiO to the metal surface. In the passive range, dissolution of Ni[sup 2+] proceeds after diffusion of Ni[sup 2+] through the oxide layer. The Ni[sup 2+] is formed at the metal/oxide interface. The slowest process is the diffusion of bivalent nickel ions through the passive scale. The formation of trivalent nickel ions probably takes place at the oxide/melt interface. This reaction is accompanied by the incorporation of an oxygen ion and a nickel vacancy in the NiO lattice. The trivalent nickel ions and the nickel vacancy diffuse to the bulk of the oxide scale. The slowest step in this sequence is the dissociation of the carbonate ions and the incorporation of the oxygen ion in the NiO lattice. 9 figs., 2 tabs., 11 refs.

  2. Enhanced cycle stability of micro-sized Si/C anode material with low carbon content fabricated via spray drying and in situ carbonization

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Dingsheng; Gao, Mingxia, E-mail: gaomx@zju.edu.cn; Pan, Hongge; Liu, Yongfeng; Wang, Junhua; Li, Shouquan; Ge, Hongwei

    2014-08-01

    Highlights: • Micro-sized Si/C composites were fabricated via. spray drying and carbonization. • Multi-morphology carbon was formed in the Si/C composites. • Si/C composite with 5.6 wt.% C provides significant improved cycling stability. • Multi-morphology carbon plays effective role in improving the electrochemical property. • The method provides potential for mass production of superior Si-based anode materials. - Abstract: Micro-sized Si/C composites with in situ introduced carbon of multi-morphology were fabricated via spray drying a suspension of commercial micro-sized Si and citric acid followed by a carbonization. Different ratios of Si to citric acid were used to optimize the composition and structure of the composites and thus the electrochemical performance. Carbon flakes including crooked and flat ones were well dispersed in between the Si particles, forming Si/C composites. Floc-like carbon layers and carbon fragments were also found to cover partially the Si particles. The Si/C composite with a low carbon content of 5.6 wt.% provides an initial reversible capacity of 2700 mA h/g and a capacity of 1860 mA h/g after 60 cycles at a current density of 100 mA/g as anode material for lithium-ion batteries (LIBs), which are much higher than those of pristine Si and the Si/C composites with higher carbon content. The mechanism of the enhancement of electrochemical performance of the micro-sized Si/C composite is discussed. The fabrication method and the structure design of the composites offer valuable potential in developing adaptable Si-based anode materials for industrial applications.

  3. Transport phenomena in the cathode of a molten carbonate fuel cell

    International Nuclear Information System (INIS)

    Berg, P.; Findlay, J.

    2009-01-01

    'Full text': A Molten Carbonate Fuel Cell (MCFC) is an electro-chemical energy conversion technology that runs on natural gas and employs a molten salt electrolyte. In order to keep the electrolyte in this state, the cell must be kept at a temperature above 500 C, eliminating the need for noble catalysts. There has been only a limited amount of research on modelling the transport processes inside this device, mainly due to its limited ability for mobile applications. A model for the reaction-diffusion processes within the cathode of a MCFC is developed using Fick's Law for diffusion and incorporating Darcy's Law for convection. A model for Binary Diffusion is also discussed and compared to those for Fickian diffusion. It can be shown that there exists a limiting case for diffusion across the cathode that depends on the conductivity for the liquid potential, for which there exists an analytical solution. Results are also discussed for varying diffusivities and permeabilities. Ultimately, this research focuses on the optimization of the electrode porosity to increase the power output of the fuel cell. The porosity is considered as a function of position, and is optimized using the software package MATLAB. (author)

  4. Highly stable carbon coated Mg2Si intermetallic nanoparticles for lithium-ion battery anode

    Science.gov (United States)

    Tamirat, Andebet Gedamu; Hou, Mengyan; Liu, Yao; Bin, Duan; Sun, Yunhe; Fan, Long; Wang, Yonggang; Xia, Yongyao

    2018-04-01

    Silicon is an ideal candidate anode material for Li-ion batteries (LIBs). However, it suffers from rapid capacity fading due to large volume expansion upon lithium insertion. Herein, we design and fabricate highly stable carbon coated porous Mg2Si intermetallic anode material using facile mechano-thermal technique followed by carbon coating using thermal vapour deposition (TVD), toluene as carbon source. The electrode exhibits an excellent first reversible capacity of 726 mAh g-1 at a rate of 100 mA g-1. More importantly, the electrode demonstrates high rate capability (380 mAh g-1 at high rate of 2 A g-1) as well as high cycle stability, with capacity retentions of 65% over 500 cycles. These improvements are attributable to both Mg supporting medium and the uniform carbon coating, which can effectively increase the conductivity and electronic contact of the active material and protects large volume alterations during the electrochemical cycling process.

  5. Joule-Heated Molten Regolith Electrolysis Reactor Concepts for Oxygen and Metals Production on the Moon and Mars

    Science.gov (United States)

    Sibille, Laurent; Dominguez, Jesus A.

    2012-01-01

    The technology of direct electrolysis of molten lunar regolith to produce oxygen and molten metal alloys has progressed greatly in the last few years. The development of long-lasting inert anodes and cathode designs as well as techniques for the removal of molten products from the reactor has been demonstrated. The containment of chemically aggressive oxide and metal melts is very difficult at the operating temperatures ca. 1600 C. Containing the molten oxides in a regolith shell can solve this technical issue and can be achieved by designing a Joule-heated (sometimes called 'self-heating') reactor in which the electrolytic currents generate enough Joule heat to create a molten bath. Solutions obtained by multiphysics modeling allow the identification of the critical dimensions of concept reactors.

  6. Carbon Anode Materials

    Science.gov (United States)

    Ogumi, Zempachi; Wang, Hongyu

    Accompanying the impressive progress of human society, energy storage technologies become evermore urgent. Among the broad categories of energy sources, batteries or cells are the devices that successfully convert chemical energy into electrical energy. Lithium-based batteries stand out in the big family of batteries mainly because of their high-energy density, which comes from the fact that lithium is the most electropositive as well as the lightest metal. However, lithium dendrite growth after repeated charge-discharge cycles easily will lead to short-circuit of the cells and an explosion hazard. Substituting lithium metal for alloys with aluminum, silicon, zinc, and so forth could solve the dendrite growth problem.1 Nevertheless, the lithium storage capacity of alloys drops down quickly after merely several charge-discharge cycles because the big volume change causes great stress in alloy crystal lattice, and thus gives rise to cracking and crumbling of the alloy particles. Alternatively, Sony Corporation succeeded in discovering the highly reversible, low-voltage anode, carbonaceous material and commercialized the C/LiCoO2 rocking chair cells in the early 1990s.2 Figure 3.1 schematically shows the charge-discharge process for reversible lithium storage in carbon. By the application of a lithiated carbon in place of a lithium metal electrode, any lithium metal plating process and the conditions for the growth of irregular dendritic lithium could be considerably eliminated, which shows promise for reducing the chances of shorting and overheating of the batteries. This kind of lithium-ion battery, which possessed a working voltage as high as 3.6 V and gravimetric energy densities between 120 and 150 Wh/kg, rapidly found applications in high-performance portable electronic devices. Thus the research on reversible lithium storage in carbonaceous materials became very popular in the battery community worldwide.

  7. Three-dimensional core-shell Fe{sub 2}O{sub 3} @ carbon/carbon cloth as binder-free anode for the high-performance lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiaohua; Zhang, Miao [School of Materials Science and Engineering and Tianjin Key Laboratory of Composites and Functional Materials, Tianjin University, Tianjin 300350 (China); Liu, Enzuo, E-mail: ezliu@tju.edu.cn [School of Materials Science and Engineering and Tianjin Key Laboratory of Composites and Functional Materials, Tianjin University, Tianjin 300350 (China); Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300350 (China); He, Fang; Shi, Chunsheng [School of Materials Science and Engineering and Tianjin Key Laboratory of Composites and Functional Materials, Tianjin University, Tianjin 300350 (China); He, Chunnian [School of Materials Science and Engineering and Tianjin Key Laboratory of Composites and Functional Materials, Tianjin University, Tianjin 300350 (China); Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300350 (China); Li, Jiajun [School of Materials Science and Engineering and Tianjin Key Laboratory of Composites and Functional Materials, Tianjin University, Tianjin 300350 (China); Zhao, Naiqin, E-mail: nqzhao@tju.edu.cn [School of Materials Science and Engineering and Tianjin Key Laboratory of Composites and Functional Materials, Tianjin University, Tianjin 300350 (China); Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300350 (China)

    2016-12-30

    Highlights: • The 3D core-shell Fe{sub 2}O{sub 3}@C/CC structure is fabricated by simple hydrothermal route. • The composite connected 3D carbon networks consist of carbon cloth, Fe{sub 2}O{sub 3} nanorods and outer carbon layer. • The Fe{sub 2}O{sub 3}@C/CC used as binder-free anode in LIBs, demonstrates excellent performances. - Abstract: A facile and scalable strategy is developed to fabricate three dimensional core-shell Fe{sub 2}O{sub 3} @ carbon/carbon cloth structure by simple hydrothermal route as binder-free lithium-ion battery anode. In the unique structure, carbon coated Fe{sub 2}O{sub 3} nanorods uniformly disperse on carbon cloth which forms the conductive carbon network. The hierarchical porous Fe{sub 2}O{sub 3} nanorods in situ grown on the carbon cloth can effectively shorten the transfer paths of lithium ions and reduce the contact resistance. The carbon coating significantly inhibits pulverization of active materials during the repeated Li-ion insertion/extraction, as well as the direct exposure of Fe{sub 2}O{sub 3} to the electrolyte. Benefiting from the structural integrity and flexibility, the nanocomposites used as binder-free anode for lithium-ion batteries, demonstrate high reversible capacity and excellent cyclability. Moreover, this kind of material represents an alternative promising candidate for flexible, cost-effective, and binder-free energy storage devices.

  8. Multi-walled carbon nanotube/SnO2 nanocomposite: a novel anode material for microbial fuel cells

    International Nuclear Information System (INIS)

    Mehdinia, Ali; Ziaei, Ehsan; Jabbari, Ali

    2014-01-01

    Nanocomposit of multi-walled carbon nanotubes and tin oxide (MWCNTs/SnO 2 ) was used as an anode material in Microbial fuel cells (MFCs). The anode was constructed by coating of the nanocomposits on the glassy carbon electrode (GCE). The MWCNTs-SnO 2 /GCE showed the highest electrochemical performance as compared to MWCNT/GCE and bare GCE anodes. MWCNTs-SnO 2 /GCE, MWCNT/GCE and bare GCE anodes showed maximum power densities of 1421 mWm −2 , 699 mW m −2 and 457 mW m −2 , respectively. The electrodes were characterized by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The electrochemical properties of the MFC have been investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). High conductivity and large unique surface area extremely enhanced the charge transfer efficiency and the growth of bacterial biofilm on the electrode surface in MFC. Comparison of the power density of the proposed MFC with the other one in the literature showed that the MWCNTs/SnO 2 nanocomposit was a desirable anode material for the MFCs

  9. Wetting of a Charged Surface of Glassy Carbon by Molten Alkali-Metal Chlorides

    Science.gov (United States)

    Stepanov, V. P.

    2018-03-01

    Values of the contact angle of wetting of a surface of glassy carbon by molten chlorides of lithium, sodium, potassium, and cesium are measured by the meniscus weight method to determine the common factors of wettability of solid surfaces by ionic melts upon a change in the salt phase composition and a jump in electric potential. It is found that with a potential shift in the positive direction the shape of the curve of the contact angle's dependence on the potential varies upon substitution of one salt by another: the angle of wetting shrinks monotonously in lithium chloride but remains constant in molten cesium chloride. This phenomenon is explained by the hypothesis that the nature of the halide anion adsorption on the positively charged surface of an electrode is chemical and not electrostatic. It is shown that the adsorption process is accompanied by charge transfer through the interface, with covalent bonding between the adsorbent and adsorbate.

  10. Direct Electrolysis of Molten Lunar Regolith for the Production of Oxygen and Metals on the Moon

    Science.gov (United States)

    Sirk, Aislinn H. C.; Sadoway, Donald R.; Sibille, Laurent

    2010-01-01

    When considering the construction of a lunar base, the high cost ($ 100,000 a kilogram) of transporting materials to the surface of the moon is a significant barrier. Therefore in-situ resource utilization will be a key component of any lunar mission. Oxygen gas is a key resource, abundant on earth and absent on the moon. If oxygen could be produced on the moon, this provides a dual benefit. Not only does it no longer need to be transported to the surface for breathing purposes; it can also be used as a fuel oxidizer to support transportation of crew and other materials more cheaply between the surface of the moon, and lower earth orbit (approximately $20,000/kg). To this end a stable, robust (lightly manned) system is required to produce oxygen from lunar resources. Herein, we investigate the feasibility of producing oxygen, which makes up almost half of the weight of the moon by direct electrolysis of the molten lunar regolith thus achieving the generation of usable oxygen gas while producing primarily iron and silicon at the cathode from the tightly bound oxides. The silicate mixture (with compositions and mechanical properties corresponding to that of lunar regolith) is melted at temperatures near 1600 C. With an inert anode and suitable cathode, direct electrolysis (no supporting electrolyte) of the molten silicate is carried out, resulting in production of molten metallic products at the cathode and oxygen gas at the anode. The effect of anode material, sweep rate, and electrolyte composition on the electrochemical behavior was investigated and implications for scale-up are considered. The activity and stability of the candidate anode materials as well as the effect of the electrolyte composition were determined. Additionally, ex-situ capture and analysis of the anode gas to calculate the current efficiency under different voltages, currents and melt chemistries was carried out.

  11. Ceramic carbon electrode-based anodes for use in the copper-chlorine thermochemical cycle

    Energy Technology Data Exchange (ETDEWEB)

    Ranganathan, S.; Easton, E.B. [Univ. of Ontario Inst. of Technology, Oshawa, ON (Canada). Faculty of Science

    2009-07-01

    A thermochemical cycle is a process by which water is decomposed into hydrogen and oxygen through a series of chemical reactions. The chemicals that are used in these reactions are regenerated and recycled during the process. Sol-gel chemistry is becoming more common for the synthesis of electrode materials. The sol-gel reaction can be conducted in the presence of a carbon black to form a ceramic carbon electrode (CCE). The resultant CCE structure contains electronically conductive carbon particle pathways that are bound together through the ceramic binder, which can also promote ion transport. The CCE structure also has a high active surface area and is chemically and thermally robust. This paper presented an investigation of CCE materials prepared using 3-aminopropyl trimethoxysilane. Several electrochemical experiments including cyclic voltammetry and electrochemical impedance spectroscopy were performed to characterize their suitability as anode electrode materials for use in the electrochemical step of the copper-chlorine thermochemical cycle. Subsequent experiments included the manipulation of the relative ratio of organosilane carbon precursors to gauge its impact on electrode properties and performance. An overview of the materials characterization and electrochemical measurements were also presented. Specifically, the paper presented the experiment with particular reference to the CCE preparation; electrochemical experiments; thermal analysis; and scanning electron microscopy. Results were also provided. These included TGA analysis; scanning electron microscopy analysis; electrochemical characterization; and anodic polarization. Characterization of these CCE material demonstrated that they had good thermal stability, could be used at high temperatures, and were therefore, very promising anode materials. 15 refs., 7 figs.

  12. Enhanced performance of microbial fuel cells by using MnO_2/Halloysite nanotubes to modify carbon cloth anodes

    International Nuclear Information System (INIS)

    Chen, Yingwen; Chen, Liuliu; Li, Peiwen; Xu, Yuan; Fan, Mengjie; Zhu, Shemin; Shen, Shubao

    2016-01-01

    The modification of anode materials is important to enhance the power generation of MFCs (microbial fuel cells). A novel and cost-effective modified anode that is fabricated by dispersing manganese dioxide (MnO_2) and HNTs (Halloysite nanotubes) on carbon cloth to improve the MFCs' power production was reported. The results show that the MnO_2/HNT anodes acquire more bacteria and provide greater kinetic activity and power density compared to the unmodified anode. Among all modified anodes, 75 wt% MnO_2/HNT exhibits the highest electrochemical performance. The maximum power density is 767.3 mWm"−"2, which 21.6 higher than the unmodified anode (631 mW/m"2). Besides, CE (Coulombic efficiency) was improved 20.7, indicating that more chemical energy transformed to electricity. XRD (X-Ray powder diffraction) and FTIR (Fourier transform infrared spectroscopy) are used to characterize the structure and functional groups of the anode. CV (cyclic voltammetry) scans and SEM (scanning electron microscope) images demonstrate that the measured power density is associated with the attachment of bacteria, the microorganism morphology differed between the modified and the original anode. These findings demonstrate that MnO_2/HNT nanocomposites can alter the characteristics of carbon cloth anodes to effectively modify the anode for practical MFC applications. - Highlights: • Different contents of MnO_2/HNT composites were prepared and used to modify anodes in MFCs. • The performance of MFCs was improved by the anode modification. • 75% wt MnO_2/HNT modified anode showed the better capacity on power density. • Water contact angle, CV, SEM were determined to figure out the effect of modification on MFCs. • MnO_2/HNT modified anode in MFCs was first studied to push MFCs technology forward.

  13. Kinetic studies on the removal of fission products from molten salt using Zeolite-4A. Contributed Paper RD-15

    International Nuclear Information System (INIS)

    Shafi, Suheel; Prabhakara Reddy, B.; Perumal, S.V.; Nagarajan, K.

    2014-01-01

    Molten salt electrorefining process is one of the nonaqueous processes, being developed for reprocessing metallic spent fuel. This process uses liquid metals and molten salts and is operated at elevated temperatures. In the electro-refining process, the spent fuel is used as the anode of the electro-refiner and the actinide elements in the spent fuel are electrotransported from the anode through the molten salt electrolyte onto a suitable cathode where they are collected as metals in pure form. After some batches are processed, chlorides of fission products such as alkali, alkaline earth and rare earth metals accumulate in the electrolyte salt. The accumulated FPs in the salt will be removed by adsorption/ion-exchange by using zeolite columns. Hence, kinetic studies on the adsorption of Cs, Ba which are some of the major FP products in LiCI-KCI eutectic, have been carried out

  14. Anodic polarization behavior of pure copper in carbonate solutions

    International Nuclear Information System (INIS)

    Kawasaki, Manabu; Taniguchi, Naoki; Naitou, Morimasa

    2008-03-01

    Copper is one of the candidate materials for overpacks. The redox condition at the early stage of the post closure will be oxidizing. In order to understand the influence of environmental factors on the corrosion behavior of copper in such oxidizing environment, anodic polarization tests were performed in carbonate aqueous solution with varying the concentration of representative chemical species in groundwater. As the results of potentiodynamic and potentiostatic tests, anodic polarization behavior of pure copper was summarized as follows; Carbonate ion and bicarbonate ion promoted the passivation of pure copper, and suppressed the initiation of film breakdown. Chloride ion promoted both the active dissolution and initiation of film breakdown of pure copper. The influence of sulfate ion and pH was small, but the action of sulfate ion to the pure copper was similar to that of chloride ion, and the increase of pH was likely to promote the passivation and suppress the initiation of film breakdown. The film breakdown potential, Eb, was represented as a function of the ratio of aggressive ion and inhibiting ion such as [Cl - ]/[HCO 3 - ], [SO 4 2- ]/[HCO 3 - ]. When the ratio exceeds a certain value, the anodic polarization curve becomes active dissolution type so that no macroscopic film breakdown can not be occurred. The lower limit of Eb in passive type region was estimated to be about -200 mV vs. SCE. As the results of potentio static tests, the corrosion form near the Eb was uniform dissolution over the surface, but pitting corrosion and non-uniform corrosion occurred according to the condition of the test solution. Neither pitting corrosion nor non-uniform corrosion occurred at the potential below Eb in every test cases. (author)

  15. Wettability between TiN,TiC Containing Carbon Composite Refractory and Molten Slag or Hot Metal

    Institute of Scientific and Technical Information of China (English)

    SHIYue-xun; LIYingand; 等

    1994-01-01

    In order to develop a new-type TiC-TiN containing carbon composite refractory so as to improve the service life of blast furnace hearth,the wettability between the carbon refractory and molten slag or metal has been mea-sured.It was indicated that the carbon refractory is wet-ted by slag(θ≤90°) when(TiC+TiN)>33.52%,The effects of TiN or TiC on wetting behavior are basi-cally identical.When the amount of TiC in the carbon com-posite refractory is greater than 60% it will be wetted by hot metal;therefore,the carbon composite refractory will be wetted by slag but not permeated by hot metal when the amount of TiC is restricted.

  16. A facile route for growth of CNTs on Si@hard carbon for conductive agent incorporating anodes for lithium-ion batteries.

    Science.gov (United States)

    Kim, Chanhoon; Choi, Sinho; Yoo, Seungmin; Kwon, Dohyoung; Ko, Seunghee; Kim, Ju-Myung; Lee, Sang-Young; Kim, Il-Doo; Park, Soojin

    2015-07-14

    Conductive agent incorporating Si anodes consisting of directly grown carbon nanotubes on hard carbon encapsulating Si nanoparticles were prepared by a one-pot chemical vapour deposition process. Owing to this fabulous structure, Si-based anodes exhibit excellent cycle retention and rate capability with a high-mass-loading of 3.5 mg cm(-2).

  17. A novel bio-electrochemical system with sand/activated carbon separator, Al anode and bio-anode integrated micro-electrolysis/electro-flocculation cost effectively treated high load wastewater with energy recovery.

    Science.gov (United States)

    Gao, Changfei; Liu, Lifen; Yang, Fenglin

    2018-02-01

    A novel bio-electrochemical system (BES) was developed by integrating micro-electrolysis/electro-flocculation from attaching a sacrificing Al anode to the bio-anode, it effectively treated high load wastewater with energy recovery (maximum power density of 365.1 mW/m 3 and a maximum cell voltage of 0.97 V), and achieving high removals of COD (>99.4%), NH 4 + -N (>98.7%) and TP (>98.6%). The anode chamber contains microbes, activated carbon (AC)/graphite granules and Al anode. It was separated from the cathode chamber containing bifunctional catalytic and filtration membrane cathode (loaded with Fe/Mn/C/F/O catalyst) by a multi-medium chamber (MMC) filled with manganese sand and activated carbon granules, which replaced expensive PEM and reduced cost. An air contact oxidation bed for aeration was still adopted before liquid entering the cathode chamber. micro-electrolysis/electro-flocculation helps in achieving high removal efficiencies and contributes to membrane fouling migration. The increase of activated carbon in the separator MMC increased power generation and reduced system electric resistance. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Heteroatom Doped-Carbon Nanospheres as Anodes in Lithium Ion Batteries.

    Science.gov (United States)

    Pappas, George S; Ferrari, Stefania; Huang, Xiaobin; Bhagat, Rohit; Haddleton, David M; Wan, Chaoying

    2016-01-09

    Long cycle performance is a crucial requirement in energy storage devices. New formulations and/or improvement of "conventional" materials have been investigated in order to achieve this target. Here we explore the performance of a novel type of carbon nanospheres (CNSs) with three heteroatom co-doped (nitrogen, phosphorous and sulfur) and high specific surface area as anode materials for lithium ion batteries. The CNSs were obtained from carbonization of highly-crosslinked organo (phosphazene) nanospheres (OPZs) of 300 nm diameter. The OPZs were synthesized via a single and facile step of polycondensation reaction between hexachlorocyclotriphosphazene (HCCP) and 4,4'-sulphonyldiphenol (BPS). The X-ray Photoelectron Spectroscopy (XPS) analysis showed a high heteroatom-doping content in the structure of CNSs while the textural evaluation from the N₂ sorption isotherms revealed the presence of micro- and mesopores and a high specific surface area of 875 m²/g. The CNSs anode showed remarkable stability and coulombic efficiency in a long charge-discharge cycling up to 1000 cycles at 1C rate, delivering about 130 mA·h·g -1 . This study represents a step toward smart engineering of inexpensive materials with practical applications for energy devices.

  19. Synthesis and electrochemical performances of amorphous carbon-coated Sn Sb particles as anode material for lithium-ion batteries

    Science.gov (United States)

    Wang, Zhong; Tian, Wenhuai; Liu, Xiaohe; Yang, Rong; Li, Xingguo

    2007-12-01

    The amorphous carbon coating on the Sn-Sb particles was prepared from aqueous glucose solutions using a hydrothermal method. Because the outer layer carbon of composite materials is loose cotton-like and porous-like, it can accommodate the expansion and contraction of active materials to maintain the stability of the structure, and hinder effectively the aggregation of nano-sized alloy particles. The as-prepared composite materials show much improved electrochemical performances as anode materials for lithium-ion batteries compared with Sn-Sb alloy and carbon alone. This amorphous carbon-coated Sn-Sb particle is extremely promising anode materials for lithium secondary batteries and has a high potentiality in the future use.

  20. The Solubility of metal oxides in molten carbonates - why the acid-basic chemistry fails?

    DEFF Research Database (Denmark)

    Bjerrum, Niels; Qingfeng, Li; Borup, Flemming

    1999-01-01

    Solubilities of various metal oxides in molten Li/K carbonates have been measured at 650°C under carbon dioxide atmosphere. It is found that the solubility of NiO and PbO decreases with increasing lithium mole fraction and decreasing CO2 partial pressure. On the other hand, the emf measurement...... shows opposite effects, i.e., decreasing CO2 pressure leads to more negative emf values but increasing lithium content gives more positive emf values. This contradiction is explained by means of a complex formation model. The possible species for lead are proposed to be [Pb(CO3)2]-2 and/or [Pb(CO3) 3...

  1. MoS2 coated hollow carbon spheres for anodes of lithium ion batteries

    International Nuclear Information System (INIS)

    Zhang, Yufei; Wang, Ye; Shi, Wenhui; Yang, Huiying; Yang, Jun; Huang, Wei; Dong, Xiaochen

    2016-01-01

    With the assistance of resorcinol–formaldehyde, MoS 2 coated hollow carbon spheres (C@MoS 2 ) were synthesized through a facile hydrothermal route followed by heat and alkali treatments. The measurements indicate that the hollow carbon spheres with an average diameter of 300 nm and shell thickness of 20 nm. And the hollow core are uniformly covered by ultrathin MoS 2 nanosheets with a length increased to 400 nm. The unique hollow structure and the synergistic effect between carbon layer and MoS 2 nanosheets significantly enhance the rate capability and electrochemical stability of C@MoS 2 spheres as anode material of lithium-ion battery. The synthesized C@MoS 2 delivered a capacity of 750 mAh g −1 at a current density of 100 mA g −1 . More importantly, the C@MoS 2 maintained a reversible capacity of 533 mAh g −1 even at a high current density of 1000 mA g −1 . The study indicated that MoS 2 coated hollow carbon spheres can be promising anode material for next generation high-performance lithium-ion batteries. (paper)

  2. Mesostructured platinum-free anode and carbon-free cathode catalysts for durable proton exchange membrane fuel cells.

    Science.gov (United States)

    Cui, Xiangzhi; Shi, Jianlin; Wang, Yongxia; Chen, Yu; Zhang, Lingxia; Hua, Zile

    2014-01-01

    As one of the most important clean energy sources, proton exchange membrane fuel cells (PEMFCs) have been a topic of extensive research focus for decades. Unfortunately, several critical technique obstacles, such as the high cost of platinum electrode catalysts, performance degradation due to the CO poisoning of the platinum anode, and carbon corrosion by oxygen in the cathode, have greatly impeded its commercial development. A prototype of a single PEMFC catalyzed by a mesostructured platinum-free WO3/C anode and a mesostructured carbon-free Pt/WC cathode catalysts is reported herein. The prototype cell exhibited 93% power output of a standard PEMFC using commercial Pt/C catalysts at 50 and 70 °C, and more importantly, CO poisoning-free and carbon corrosion-resistant characters of the anode and cathode, respectively. Consequently, the prototype cell demonstrated considerably enhanced cell operation durability. The mesostructured electrode catalysts are therefore highly promising in the future development and application of PEMFCs. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Binder-free graphene and manganese oxide coated carbon felt anode for high-performance microbial fuel cell.

    Science.gov (United States)

    Zhang, Changyong; Liang, Peng; Yang, Xufei; Jiang, Yong; Bian, Yanhong; Chen, Chengmeng; Zhang, Xiaoyuan; Huang, Xia

    2016-07-15

    A novel anode was developed by coating reduced graphene oxide (rGO) and manganese oxide (MnO2) composite on the carbon felt (CF) surface. With a large surface area and excellent electrical conductivity, this binder-free anode was found to effectively enhance the enrichment and growth of electrochemically active bacteria and facilitate the extracellular electron transfer from the bacteria to the anode. A microbial fuel cell (MFC) equipped with the rGO/MnO2/CF anode delivered a maximum power density of 2065mWm(-2), 154% higher than that with a bare CF anode. The internal resistance of the MFC with this novel anode was 79Ω, 66% lower than the regular one's (234Ω). Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) analyses affirmed that the rGO/MnO2 composite significantly increased the anodic reaction rates and facilitated the electron transfer from the bacteria to the anode. The findings from this study suggest that the rGO/MnO2/CF anode, fabricated via a simple dip-coating and electro-deposition process, could be a promising anode material for high-performance MFC applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Thorium-based Molten Salt Reactor (TMSR) project in China

    International Nuclear Information System (INIS)

    Dai, Zhimin; Liu, Wei

    2013-01-01

    Making great efforts in development of nuclear energy is one of the long-term-plan in China's energy strategies. The advantages of Thorium-based nuclear energy are: rich resource in nature, less nuclear waste, low toxicity, nuclear non-proliferation and so on. Furthermore, China is a country with abundant thorium, thus it is necessary to develop the Thorium-based Molten Salt Reactor (TMSR) in China. Shanghai Institute of Applied Physics, Chinese Academy of Sciences (SINAP) had designed and constructed the first China's light-water reactor and developed a zero-power thorium-based molten salt reactor successfully in the early 1970s. The applied research project 'thorium molten salt reactor nuclear power system' by SINAP together with several other institutes had been accepted and granted by China government in 2011. The whole project has been divided into three stages: Firstly, built a 2 MW-zero-power high temperature solid molten salt reactor in 2015 and a 2 MW-zero-power high temperature liquid molten salt reactor in 2017. Secondly, in 2020 built a 10 MW high temperature liquid molten salt reactor. Thirdly, on the base of previous work, a 100 MW high temperature molten salt reactor should be achieving in 2030. After more than one years of efforts, a high quality scientific research team has been formed, which is able to design the molten salt reactor, the molten salt loop and related key equipment, the systems of molten salt preparation, purification and the radioactive gas removal. In the past one year, the initial physical design of high temperature molten salt reactor has been completed; the nuclear chemistry and radiation chemical laboratory has been built, a high temperature salt (HTS) loop and radioactive gas removal experiment device system have been successfully developed and constructed. Further, the preliminary study on reactor used carbon-carbon composite material has been investigated. (author)

  5. Metallic oxide reduction in molten chlorides: electrochemical solvent regeneration

    International Nuclear Information System (INIS)

    Martin, A.

    2005-11-01

    We consider the reaction MeO 2 + 2 Ca → Me + 2 CaO in CaCl 2 at 850 C. We want to re-use the molten media, which is a CaO-CaCl 2 melt at the end of the reaction. For that we want to de-oxidize it. When we electrolyse CaO we obtain Ca and O 2 ; it presents three difficult points that we want to solve: (1) it is difficult to oxidize O 2 - without oxidizing Cl - because their oxidation potential are very closed, (2) the chemical or electrochemical anodic corrosion, (3) the anodically produced gas dissolution in the mell One way of avoiding chlorine gas evolution is to prevent chloride ions from reaching the anode, for example using a selective membrane. Furthermore, the best prevention of the anodically produced gas dissolution in the melt can be done with a compartment, physically separating the anode from the rest of the reactional media. Thus in this work we have used an yttria stabilized zirconia membrane as a selective membrane for the deoxidation of a CaO-CaCl 2 melt at 850 C. (author)

  6. Graphitized biogas-derived carbon nanofibers as anodes for lithium-ion batteries

    International Nuclear Information System (INIS)

    Cuesta, Nuria; Cameán, Ignacio; Ramos, Alberto; García, Ana B.

    2016-01-01

    The electrochemical performance as potential anodes for lithium-ion batteries of graphitized biogas-derived carbon nanofibers (BCNFs) is investigated by galvanostatic cycling versus Li/Li + at different electrical current densities. These graphitic nanomaterials have been prepared by high temperature treatment of carbon nanofibers produced in the catalytic decomposition of biogas. At low current density, they deliver specific capacities comparable to that of oil-derived micrometric graphite, the capacity retention values being mostly in the range 70-80% and cycling efficiency ∼ 100%. A clear tendency of the anode capacity to increase alongside the BCNFs crystal thickness was observed. Besides the degree of graphitic tri-dimensional structural order, the presence of loops between the adjacent edges planes on the graphene layers, the mesopore volume and the active surface area of the graphitized BCNFs were found to influence on battery reversible capacity, capacity retention along cycling and irreversible capacity. Furthermore, provided that the development of the crystalline structure is comparable, the graphitized BCNFs studied show better electrochemical rate performance than micrometric graphite. Therefore, this result can be associated with the nanometric particle size as well as the larger surface area of the BCNFs which, respectively, reduces the diffusion time of the lithium ions for the intercalation/de-intercalation processes, i.e. faster charge-discharge rate, and increases the contact area at the anode active material/electrolyte interface which may improve the Li + ions access, i.e. charge transfer reaction.

  7. Porous Carbon Spheres Doped with Fe_3C as an Anode for High-Rate Lithium-ion Batteries

    International Nuclear Information System (INIS)

    Chen, Shouhui; Wu, Jiafeng; Zhou, Rihui; Zuo, Li; Li, Ping; Song, Yonghai; Wang, Li

    2015-01-01

    Highlights: • Novel porous carbon spheres doped with Fe_3C was prepared via hydrothermal reaction. • The resulted material was fabricated as an anode for high-rate lithium-ion batteries. • A stepwise increase profile was shown in the discharge/charge process. • Pseudocapacity was one of the properties owned by the as-prepared anode. - Abstract: The search of advanced anodes has been an important way to satisfy the ever-growing demands on high rate performance lithium-ion batteries (LIBs). It was observed that the capacity of Fe_3C as an anode is larger than its theoretical one, which might be attributed to the pseudocapacity on the interface between the carbide and electrolyte. In this work, a novel carbon sphere doped with Fe_3C nanoparticles was fabricated and tested as the anode in LIBs. In the first place, iron precursors were embedded in the cross-link polymer resorcinol-formaldehyde (RF) spheres via a facile hydrothermal reaction, in which RF served as the carbon source and ethanol as a dispersant agent. Consequently, the hydrothermal products were carbonized successively at 700 °C under inert atmosphere to obtain porous carbon spheres doped with Fe_3C. When the composite severed as an anode in LIBs, its discharge capacity increased to the largest during the first 250-400 cycles, then dropped down to a similar level of that after 1000 cycles at different current rates. The discharge capacity of the composite increased from ∼300 mAh g"−"1 to ∼540 mAh g"−"1 at the current of 100 mA g"−"1 during the initial hundreds cycles, and even a discharge capacity of ∼230 mAh g"−"1 at the current of 2000 mA g"−"1. Moreover, it was observed that a discharge plateau gradually appeared between 0.7∼1.1 V during the first hundreds of cycles. The electrochemical behaviors of the anode before 1000 discharge/charge cycles were compared with that after 1000 discharge/charge cycles by cyclic voltammetry and electrochemical impedance spectroscopy to find

  8. Evaluation of gasification and gas cleanup processes for use in molten carbonate fuel cell power plants. Final report. [Contains lists and evaluations of coal gasification and fuel gas desulfurization processes

    Energy Technology Data Exchange (ETDEWEB)

    Jablonski, G.; Hamm, J.R.; Alvin, M.A.; Wenglarz, R.A.; Patel, P.

    1982-01-01

    This report satisfies the requirements for DOE Contract AC21-81MC16220 to: List coal gasifiers and gas cleanup systems suitable for supplying fuel to molten carbonate fuel cells (MCFC) in industrial and utility power plants; extensively characterize those coal gas cleanup systems rejected by DOE's MCFC contractors for their power plant systems by virtue of the resources required for those systems to be commercially developed; develop an analytical model to predict MCFC tolerance for particulates on the anode (fuel gas) side of the MCFC; develop an analytical model to predict MCFC anode side tolerance for chemical species, including sulfides, halogens, and trace heavy metals; choose from the candidate gasifier/cleanup systems those most suitable for MCFC-based power plants; choose a reference wet cleanup system; provide parametric analyses of the coal gasifiers and gas cleanup systems when integrated into a power plant incorporating MCFC units with suitable gas expansion turbines, steam turbines, heat exchangers, and heat recovery steam generators, using the Westinghouse proprietary AHEAD computer model; provide efficiency, investment, cost of electricity, operability, and environmental effect rankings of the system; and provide a final report incorporating the results of all of the above tasks. Section 7 of this final report provides general conclusions.

  9. Rotating disk electrode study of borohydride oxidation in a molten eutectic electrolyte and advancements in the intermediate temperature borohydride battery

    Science.gov (United States)

    Wang, Andrew; Gyenge, Előd L.

    2017-08-01

    The electrode kinetics of the NaBH4 oxidation reaction (BOR) in a molten NaOH-KOH eutectic mixture is investigated by rotating disk electrode (RDE) voltammetry on electrochemically oxidized Ni at temperatures between 458 K and 503 K. The BH4- diffusion coefficient in the molten alkali eutectic together with the BOR activation energy, exchange current density, transfer coefficient and number of electrons exchanged, are determined. Electrochemically oxidized Ni shows excellent BOR electrocatalytic activity with a maximum of seven electrons exchanged and a transfer coefficient up to one. X-ray photoelectron spectroscopy (XPS) reveals the formation of NiO as the catalytically active species. The high faradaic efficiency and BOR rate on oxidized Ni anode in the molten electrolyte compared to aqueous alkaline electrolytes is advantageous for power sources. A novel molten electrolyte battery design is investigated using dissolved NaBH4 at the anode and immobilized KIO4 at the cathode. This battery produces a stable open-circuit cell potential of 1.04 V, and a peak power density of 130 mW cm-2 corresponding to a superficial current density of 160 mA cm-2 at 458 K. With further improvements and scale-up borohydride molten electrolyte batteries and fuel cells could be integrated with thermal energy storage systems.

  10. Stable synthesis of few-layered boron nitride nanotubes by anodic arc discharge.

    Science.gov (United States)

    Yeh, Yao-Wen; Raitses, Yevgeny; Koel, Bruce E; Yao, Nan

    2017-06-08

    Boron nitride nanotubes (BNNTs) were successfully synthesized by a dc arc discharge using a boron-rich anode as synthesis feedstock in a nitrogen gas environment at near atmospheric pressure. The synthesis was achieved independent of the cathode material suggesting that under such conditions the arc operates in so-called anodic mode with the anode material being consumed by evaporation due to the arc heating. To sustain the arc current by thermionic electron emission, the cathode has to be at sufficiently high temperature, which for a typical arc current density of ~100 A/cm 2 , is above the boron melting point (2350 K). With both electrodes made from the same boron-rich alloy, we found that the arc operation unstable due to frequent sticking between two molten electrodes and formation of molten droplets. Stable and reliable arc operation and arc synthesis were achieved with the boron-rich anode and the cathode made from a refractory metal which has a melting temperature above the melting point of boron. Ex-situ characterization of synthesized BNNTs with electron microscopy and Raman spectroscopy revealed that independent of the cathode material, the tubes are primarily single and double walled. The results also show evidence of root-growth of BNNTs produced in the arc discharge.

  11. Porous Silicon–Carbon Composite Materials Engineered by Simultaneous Alkaline Etching for High-Capacity Lithium Storage Anodes

    International Nuclear Information System (INIS)

    Sohn, Myungbeom; Kim, Dae Sik; Park, Hyeong-Il; Kim, Jae-Hun; Kim, Hansu

    2016-01-01

    Highlights: • A porous Si–C anode is obtained by alkaline etching of a non-porous Si–C composite. • The pores in the carbon frame are created by simultaneous etching of Si and carbon. • The cycle life is greatly improved after the alkaline treatment. • The porous Si–C composite electrode shows high dimensional stability during cycling. - Abstract: Porous silicon–carbon (Si–C) composite materials have attracted a great deal of attention as high-performance anode materials for Li-ion batteries (LIBs), but their use suffers from the complex and limited synthetic routes for their preparation. Herein we demonstrate a scalable and nontoxic method to synthesize porous Si–C composite materials by means of simultaneous chemical etching of Si and carbon phases using alkaline solution. The resulting porous Si–C composite material showed greatly improved cycle performance, good rate capability, and high dimensional stability during cycling. Porous Si–C electrode showed an expansion of the height by about 22% after the first lithiation and only 16% after the first cycle. The material synthesis concept and scalable simultaneous etching approach presented here represent a means of improving the electrochemical properties of Si-based porous anode materials for use in commercial LIBs.

  12. Carbon-coated Si nanoparticles/reduced graphene oxide multilayer anchored to nanostructured current collector as lithium-ion battery anode

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhengjiao; Guo, Pengqian; Liu, Boli; Xie, Wenhe; Liu, Dequan; He, Deyan, E-mail: hedy@lzu.edu.cn

    2017-02-28

    Silicon is the most promising anode material for the next-generation lithium-ion batteries (LIBs). However, the large volume change during lithiation/delithiation and low intrinsic conductivity hamper its electrochemical performance. Here we report a well-designed LIB anode in which carbon-coated Si nanoparticles/reduced graphene oxide (Si/rGO) multilayer was anchored to nanostructured current collector with stable mechanical support and rapid electron conduction. Furthermore, we improved the integral stability of the electrode through introducing amorphous carbon. The designed anode exhibits superior cyclability, its specific capacity remains above 800 mAh g{sup −1} after 350 cycles at a current density of 2.0 A g{sup −1}. The excellent electrochemical performance can be attributed to the fact that the Si/rGO multilayer is reinforced by the nanostructured current collector and the formed amorphous carbon, which can maintain the structural and electrical integrities of the electrode.

  13. Study of a molten carbonate fuel cell combined heat, hydrogen and power system

    International Nuclear Information System (INIS)

    Hamad, Tarek A.; Agll, Abdulhakim A.; Hamad, Yousif M.; Bapat, Sushrut; Thomas, Mathew; Martin, Kevin B.; Sheffield, John W.

    2014-01-01

    To address the problem of fossil fuel usage and high greenhouse gas emissions at the Missouri University of Science and Technology campus, using of alternative fuels and renewable energy sources can lower energy consumption and greenhouse gas emissions. Biogas, produced by anaerobic digestion of wastewater, organic waste, agricultural waste, industrial waste, and animal by-products is a potential source of renewable energy. In this work, we have discussed the design of CHHP (combined heat, hydrogen and power) system for the campus using local resources. An energy flow and resource availability study is performed to identify the type and source of feedstock required to continuously run the fuel cell system at peak capacity. Following the resource assessment study, the team selects FuelCell Energy DFC (direct fuel cell) 1500™ unit as a molten carbonate fuel cell. The CHHP system provides electricity to power the university campus, thermal energy for heating the anaerobic digester, and hydrogen for transportation, back-up power and other needs. In conclusion, the CHHP system will be able to reduce fossil fuel usage, and greenhouse gas emissions at the university campus. - Highlights: • A molten carbonate fuel cell tri-generation by using anaerobic digestion system. • Anaerobic digestion system will be able to supply fuel for the DFC1500™ unit. • Use locally available feedstock to production electric power, hydrogen and heat. • Application energy end-uses on the university. • CHHP system will reduce energy consumption, fossil fuel usage, and GHG emissions

  14. Synthesis of Ultrathin Si Nanosheets from Natural Clays for Lithium-Ion Battery Anodes.

    Science.gov (United States)

    Ryu, Jaegeon; Hong, Dongki; Choi, Sinho; Park, Soojin

    2016-02-23

    Two-dimensional Si nanosheets have been studied as a promising candidate for lithium-ion battery anode materials. However, Si nanosheets reported so far showed poor cycling performances and required further improvements. In this work, we utilize inexpensive natural clays for preparing high quality Si nanosheets via a one-step simultaneous molten salt-induced exfoliation and chemical reduction process. This approach produces high purity mesoporous Si nanosheets in high yield. As a control experiment, two-step process (pre-exfoliated silicate sheets and subsequent chemical reduction) cannot sustain their original two-dimensional structure. In contrast, one-step method results in a production of 5 nm-thick highly porous Si nanosheets. Carbon-coated Si nanosheet anodes exhibit a high reversible capacity of 865 mAh g(-1) at 1.0 A g(-1) with an outstanding capacity retention of 92.3% after 500 cycles. It also delivers high rate capability, corresponding to a capacity of 60% at 20 A g(-1) compared to that of 2.0 A g(-1). Furthermore, the Si nanosheet electrodes show volume expansion of only 42% after 200 cycles.

  15. Coaxial MoS2@Carbon Hybrid Fibers: A Low-Cost Anode Material for High-Performance Li-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Rui Zhou

    2017-02-01

    Full Text Available A low-cost bio-mass-derived carbon substrate has been employed to synthesize MoS2@carbon composites through a hydrothermal method. Carbon fibers derived from natural cotton provide a three-dimensional and open framework for the uniform growth of MoS2 nanosheets, thus hierarchically constructing coaxial architecture. The unique structure could synergistically benefit fast Li-ion and electron transport from the conductive carbon scaffold and porous MoS2 nanostructures. As a result, the MoS2@carbon composites—when serving as anodes for Li-ion batteries—exhibit a high reversible specific capacity of 820 mAh·g−1, high-rate capability (457 mAh·g−1 at 2 A·g−1, and excellent cycling stability. The use of bio-mass-derived carbon makes the MoS2@carbon composites low-cost and promising anode materials for high-performance Li-ion batteries.

  16. Heteroatom Doped-Carbon Nanospheres as Anodes in Lithium Ion Batteries

    Directory of Open Access Journals (Sweden)

    George S. Pappas

    2016-01-01

    Full Text Available Long cycle performance is a crucial requirement in energy storage devices. New formulations and/or improvement of “conventional” materials have been investigated in order to achieve this target. Here we explore the performance of a novel type of carbon nanospheres (CNSs with three heteroatom co-doped (nitrogen, phosphorous and sulfur and high specific surface area as anode materials for lithium ion batteries. The CNSs were obtained from carbonization of highly-crosslinked organo (phosphazene nanospheres (OPZs of 300 nm diameter. The OPZs were synthesized via a single and facile step of polycondensation reaction between hexachlorocyclotriphosphazene (HCCP and 4,4′-sulphonyldiphenol (BPS. The X-ray Photoelectron Spectroscopy (XPS analysis showed a high heteroatom-doping content in the structure of CNSs while the textural evaluation from the N2 sorption isotherms revealed the presence of micro- and mesopores and a high specific surface area of 875 m2/g. The CNSs anode showed remarkable stability and coulombic efficiency in a long charge–discharge cycling up to 1000 cycles at 1C rate, delivering about 130 mA·h·g−1. This study represents a step toward smart engineering of inexpensive materials with practical applications for energy devices.

  17. Low-Surface-Area Hard Carbon Anode for Na-Ion Batteries via Graphene Oxide as a Dehydration Agent

    Energy Technology Data Exchange (ETDEWEB)

    Luo, W; Bommier, C; Jian, ZL; Li, X; Carter, R; Vail, S; Lu, YH; Lee, JJ; Ji, XL

    2015-02-04

    Na-ion batteries are emerging as one of the most promising energy storage technologies, particularly for grid-level applications. Among anode candidate materials, hard carbon is very attractive due to its high capacity and low cost. However, hard carbon anodes often suffer a low first-cycle Coulombic efficiency and fast capacity fading. In this study, we discover that doping graphene oxide into sucrose, the precursor for hard carbon, can effectively reduce the specific surface area of hard carbon to as low as 5.4 m(2)/g. We further reveal that such doping can effectively prevent foaming during caramelization of sucrose and extend the pyrolysis burnoff of sucrose caramel over a wider temperature range. The obtained low-surface-area hard carbon greatly improves the first-cycle Coulombic efficiency from 74% to 83% and delivers a very stable cyclic life with 95% of capacity retention after 200 cycles.

  18. Development of molten carbonate fuel cells for power generation

    Science.gov (United States)

    1980-04-01

    The broad and comprehensive program included elements of system definition, cell and system modeling, cell component development, cell testing in pure and contaminated environments, and the first stages of technology scale up. Single cells, with active areas of 45 sq cm and 582 sq cm, were operated at 650 C and improved to state of the art levels through the development of cell design concepts and improved electrolyte and electrode components. Performance was shown to degrade by the presence of fuel contaminants, such as sulfur and chlorine, and due to changes in electrode structure. Using conventional hot press fabrication techniques, electrolyte structures up to 20" x 20" were fabricated. Promising approaches were developed for nonhot pressed electrolyte structure fabrication and a promising electrolyte matrix material was identified. This program formed the basis for a long range effort to realize the benefits of molten carbonate fuel cell power plants.

  19. A high energy and power sodium-ion hybrid capacitor based on nitrogen-doped hollow carbon nanowires anode

    Science.gov (United States)

    Li, Dongdong; Ye, Chao; Chen, Xinzhi; Wang, Suqing; Wang, Haihui

    2018-04-01

    The sodium ion hybrid capacitor (SHC) has been attracting much attention. However, the SHC's power density is significantly confined to a low level due to the sluggish ion diffusion in the anode. Herein, we propose to use an electrode with a high double layer capacitance as the anode in the SHC instead of insertion anodes. To this aim, nitrogen doped hollow carbon nanowires (N-HCNWs) with a high specific surface area are prepared, and the high capacitive contribution during the sodium ion storage process is confirmed by a series of electrochemical measurements. A new SHC consisting of a N-HCNW anode and a commercial active carbon (AC) cathode is fabricated for the first time. Due to the hybrid charge storage mechanism combining ion insertion and capacitive process, the as-fabricated SHC strikes a balance between the energy density and power density, a energy density of 108 Wh kg-1 and a power density of 9 kW kg-1 can be achieved, which overwhelms the electrochemical performances of most reported AC-based SHCs.

  20. Waste treatment using molten salt oxidation

    International Nuclear Information System (INIS)

    Navratil, J.D.; Stewart, A.E.

    1996-01-01

    MSO technology can be characterized as a submerged oxidation process; the basic concept is to introduce air and wastes into a bed of molten salt, oxidize the organic wastes in the molten salt, use the heat of oxidation to keep the salt molten and remove the salt for disposal or processing and recycling. The molten salt (usually sodium carbonate at 900-1000 C) provides four waste management functions: providing a heat transfer medium, catalyzing the oxidation reaction, preventing the formation of acid gases by forming stable salts, and efficiently capturing ash particles and radioactive materials by the combined effects of wetting, encapsulation and dissolution. The MSO process requires no wet scrubbing system for off-gas treatment. The process has been developed through bench-scale and pilot-scale testing, with successful destruction demonstration of a wide variety of hazardous and mixed (radioactive and hazardous wastes). (author). 24 refs, 2 tabs, 2 figs

  1. N/S Co-doped Carbon Derived From Cotton as High Performance Anode Materials for Lithium Ion Batteries

    Directory of Open Access Journals (Sweden)

    Jiawen Xiong

    2018-04-01

    Full Text Available Highly porous carbon with large surface areas is prepared using cotton as carbon sources which derived from discard cotton balls. Subsequently, the sulfur-nitrogen co-doped carbon was obtained by heat treatment the carbon in presence of thiourea and evaluated as Lithium-ion batteries anode. Benefiting from the S, N co-doping, the obtained S, N co-doped carbon exhibits excellent electrochemical performance. As a result, the as-prepared S, N co-doped carbon can deliver a high reversible capacity of 1,101.1 mA h g−1 after 150 cycles at 0.2 A g−1, and a high capacity of 531.2 mA h g−1 can be observed even after 5,000 cycles at 10.0 A g−1. Moreover, excellently rate capability also can be observed, a high capacity of 689 mA h g−1 can be obtained at 5.0 A g−1. This superior lithium storage performance of S, N co-doped carbon make it as a promising low-cost and sustainable anode for high performance lithium ion batteries.

  2. Porous Si spheres encapsulated in carbon shells with enhanced anodic performance in lithium-ion batteries

    International Nuclear Information System (INIS)

    Wang, Hui; Wu, Ping; Shi, Huimin; Lou, Feijian; Tang, Yawen; Zhou, Tongge; Zhou, Yiming; Lu, Tianhong

    2014-01-01

    Highlights: • In situ magnesiothermic reduction route for the formation of porous Si@C spheres. • Unique microstructural characteristics of both porous sphere and carbon matrix. • Enhanced anodic performance in term of cycling stability for lithium-ion batteries. - Abstract: A novel type of porous Si–C micro/nano-hybrids, i.e., porous Si spheres encapsulated in carbon shells (porous Si@C spheres), has been constructed through the pyrolysis of polyvinylidene fluoride (PVDF) and subsequent magnesiothermic reduction methodology by using SiO 2 spheres as precursors. The as-synthesized porous Si@C spheres have been applied as anode materials for lithium-ion batteries (LIBs), and exhibit enhanced anodic performance in term of cycling stability compared with bare Si spheres. For example, the porous Si@C spheres are able to exhibit a high reversible capacity of 900.0 mA h g −1 after 20 cycles at a current density of 0.05 C (1 C = 4200 mA g −1 ), which is much higher than that of bare Si spheres (430.7 mA h g −1 )

  3. Three-dimensional carbon network confined antimony nanoparticle anodes for high-capacity K-ion batteries.

    Science.gov (United States)

    Han, Chunhua; Han, Kang; Wang, Xuanpeng; Wang, Chenyang; Li, Qi; Meng, Jiashen; Xu, Xiaoming; He, Qiu; Luo, Wen; Wu, Liming; Mai, Liqiang

    2018-04-19

    Antimony (Sb) represents a promising anode for K-ion batteries (KIBs) due to its high theoretical capacity and suitable working voltage. However, the large volume change that occurs in the potassiation/depotassiation process can lead to severe capacity fading. Herein, we report a high-capacity anode material by in situ confining Sb nanoparticles in a three-dimensional carbon framework (3D SbNPs@C) via a template-assisted freeze-drying treatment and subsequent carbothermic reduction. The as-prepared 3D SbNPs@C hybrid material delivers high reversible capacity and good cycling stability when used as the anode for KIBs. Furthermore, cyclic voltammetry and in situ X-ray diffraction analysis were performed to reveal the intrinsic mechanism of a K-Sb alloying reaction. Therefore, this work is of great importance to understand the electrochemical process of the Sb-based alloying reaction and will pave the way for the exploration of high performance KIB anode materials.

  4. Fabrication of Si Nanoparticles@Carbon Fibers Composites from Natural Nanoclay as an Advanced Lithium-Ion Battery Flexible Anode

    Directory of Open Access Journals (Sweden)

    Sainan Liu

    2018-04-01

    Full Text Available In this paper, a cost-effective strategy for fabricating silicon-carbon composites was designed to further improve the electrochemical performance and commercialization prospects of Si anodes for lithium-ion batteries (LIBs. Silicon-carbon fibers (CFs were prepared by loading Si nanoparticles (SiNPs on interconnected carbon fibers via an electrospinning technique (SiNPs@CFs. The Si nanoparticles were obtained by the reduction reaction of natural clay minerals. As a flexible anode for LIBs, the SiNPs@CFs anode demonstrated a reversible capacity of 1238.1 mAh·g−1 and a capacity retention of 77% after 300 cycles (in contrast to the second cycle at a current density of 0.5 A·g−1. With a higher current density of 5.0 A·g−1, the electrode showed a specific capacity of 528.3 mAh·g−1 after 1000 cycles and exhibited a superior rate capability compared to Si nanoparticles. The excellent electrochemical properties were attributed to the construction of flexible electrodes and the composite comprising carbon fibers, which lessened the volume expansion and improved the conductivity of the system.

  5. Graphite coated with manganese oxide/multiwall carbon nanotubes composites as anodes in marine benthic microbial fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Yubin, E-mail: ffyybb@ouc.edu.cn; Yu, Jian; Zhang, Yelong; Meng, Yao

    2014-10-30

    Highlights: • MnO{sub 2}/MWCNTs composites anode exhibits faster reaction kinetics. • The surfaces of MnO{sub 2}/MWCNTs composites anode exhibits better wettability. • A BMFC using the modified anode have excellent power output. - Abstract: Improving anode performance is of great significance to scale up benthic microbial fuel cells (BMFCs) for its marine application to drive oceanography instruments. In this study, manganese oxide (MnO{sub 2})/multiwall carbon nanotubes (MWCNTs) composites are prepared to be as novel anodes in the BMFCs via a direct redox reaction between permanganate ions (MnO{sub 4}{sup −}) and MWCNTs. The results indicate that the MnO{sub 2}/MWCNTs anode has a better wettability, greater kinetic activity and higher power density than that of the plain graphite (PG) anode. It is noted that the MnO{sub 2} (50% weight percent)/MWCNTs anode shows the highest electrochemical performance among them and will be a promising material for improving bioelectricity production of the BMFCs. Finally, a synergistic mechanism of electron transfer shuttle of Mn ions and their redox reactions in the interface between modified anode and bacteria biofilm are proposed to explain its excellent electrochemical performance.

  6. Actinide removal from molten salts by chemical oxidation and salt distillation

    Energy Technology Data Exchange (ETDEWEB)

    McNeese, J.A.; Garcia, E.; Dole, V.R. [Los Alamos National Laboratory, NM (United States)] [and others

    1995-10-01

    Actinide removal from molten salts can be accomplished by a two step process where the actinide is first oxidized to the oxide using a chemical oxidant such as calcium carbonate or sodium carbonate. After the actinide is precipitated as an oxide the molten salt is distilled away from the actinide oxides leaving a oxide powder heel and an actinide free distilled salt that can be recycled back into the processing stream. This paper discusses the chemistry of the oxidation process and the physical conditions required to accomplish a salt distillation. Possible application of an analogous process sequence for a proposed accelerator driven transmutation molten salt process is also discussed.

  7. Actinide removal from molten salts by chemical oxidation and salt distillation

    International Nuclear Information System (INIS)

    McNeese, James A.; Garcia, Eduardo; Dole, Vonda R.; Griego, Walter J.

    1995-01-01

    Actinide removal from molten salts can be accomplished by a two step process where the actinide is first oxidized to the oxide using a chemical oxidant such as calcium carbonate or sodium carbonate. After the actinide is precipitated as an oxide the molten salt is distilled away from the actinide oxides leaving a oxide powder heel and an actinide free distilled salt that can be recycled back into the processing stream. This paper discusses the chemistry of the oxidation process and the physical conditions required to accomplish a salt distillation. Possible application of an analogous process sequence for a proposed accelerator driven transmutation molten salt process is also discussed

  8. Raman evidence of the formation of LT-LiCoO 2 thin layers on NiO in molten carbonate at 650°C

    Science.gov (United States)

    Mendoza, L.; Baddour-Hadjean, R.; Cassir, M.; Pereira-Ramos, J. P.

    2004-03-01

    The structural evolution of thin layers of Co 3O 4 elaborated on nickel-based substrates in the Li 2CO 3-Na 2CO 3 carbonate eutectic at 650 °C as a function of time immersion is reported. Raman microspectrometry has been applied in order to provide more information on the nature of the protective cobalt oxide layers. The typical Raman fingerprint of the LT-LiCoO 2 compound has been obtained, with four well defined bands at 449, 484, 590 and 605 cm -1, while XRD data are unable to distinguish the layered phase (HT) from the spinel one (LT). The mechanical stability of such films does not exceed 10 h in direct contact with the molten carbonate bulk at 650 °C; nevertheless, these conditions are much more corrosive than in a molten carbonate fuel cell (MCFC).

  9. Single-walled carbon nanotubes as stabilizing agents in red phosphorus Li-ion battery anodes

    KAUST Repository

    Smajic, Jasmin; Alazmi, Amira; Patole, Shashikant P.; Da Costa, Pedro M. F. J.

    2017-01-01

    improvement in the electrochemical stability of battery anodes. In contrast to the average 40% loss of capacity after 50 cycles for other phosphorus–carbon composites in the literature, our material shows losses of just 22% under analogous cycling conditions.

  10. Molten carbonate fuel cell

    Science.gov (United States)

    Kaun, T.D.; Smith, J.L.

    1986-07-08

    A molten electrolyte fuel cell is disclosed with an array of stacked cells and cell enclosures isolating each cell except for access to gas manifolds for the supply of fuel or oxidant gas or the removal of waste gas. The cell enclosures collectively provide an enclosure for the array and effectively avoid the problems of electrolyte migration and the previous need for compression of stack components. The fuel cell further includes an inner housing about and in cooperation with the array enclosure to provide a manifold system with isolated chambers for the supply and removal of gases. An external insulated housing about the inner housing provides thermal isolation to the cell components.

  11. Treatment of plutonium process residues by molten salt oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Stimmel, J.; Wishau, R.; Ramsey, K.B.; Montoya, A.; Brock, J. [Los Alamos National Lab., NM (United States); Heslop, M. [Naval Surface Warfare Center (United States). Indian Head Div.; Wernly, K. [Molten Salt Oxidation Corp. (United States)

    1999-04-01

    Molten Salt Oxidation (MSO) is a thermal process that can remove more than 99.999% of the organic matrix from combustible {sup 238}Pu material. Plutonium processing residues are injected into a molten salt bed with an excess of air. The salt (sodium carbonate) functions as a catalyst for the conversion of the organic material to carbon dioxide and water. Reactive species such as fluorine, chlorine, bromine, iodine, sulfur, phosphorous and arsenic in the organic waste react with the molten salt to form the corresponding neutralized salts, NaF, NaCl, NaBr, NaI, Na{sub 2}SO{sub 4}, Na{sub 3}PO{sub 4} and NaAsO{sub 2} or Na{sub 3}AsO4. Plutonium and other metals react with the molten salt and air to form metal salts or oxides. Saturated salt will be recycled and aqueous chemical separation will be used to recover the {sup 238}Pu. The Los Alamos National Laboratory system, which is currently in the conceptual design stage, will be scaled down from current systems for use inside a glovebox.

  12. Treatment of plutonium process residues by molten salt oxidation

    International Nuclear Information System (INIS)

    Stimmel, J.; Wishau, R.; Ramsey, K.B.; Montoya, A.; Brock, J.; Heslop, M.

    1999-01-01

    Molten Salt Oxidation (MSO) is a thermal process that can remove more than 99.999% of the organic matrix from combustible 238 Pu material. Plutonium processing residues are injected into a molten salt bed with an excess of air. The salt (sodium carbonate) functions as a catalyst for the conversion of the organic material to carbon dioxide and water. Reactive species such as fluorine, chlorine, bromine, iodine, sulfur, phosphorous and arsenic in the organic waste react with the molten salt to form the corresponding neutralized salts, NaF, NaCl, NaBr, NaI, Na 2 SO 4 , Na 3 PO 4 and NaAsO 2 or Na 3 AsO4. Plutonium and other metals react with the molten salt and air to form metal salts or oxides. Saturated salt will be recycled and aqueous chemical separation will be used to recover the 238 Pu. The Los Alamos National Laboratory system, which is currently in the conceptual design stage, will be scaled down from current systems for use inside a glovebox

  13. Plant-scale anodic dissolution of unirradiated IFR fuel pins

    International Nuclear Information System (INIS)

    Gay, E.C.; Tomczuk, Z.; Miller, W.E.

    1993-01-01

    This report discusses anodic dissolution which is a major operation in the pyrometallurgical process for recycling spent metal fuels from the Integral Fast Reactor (IFR), an advanced reactor design developed at Argonne National Laboratory. This process involves electrorefining the heavy metals (uranium and plutonium) from chopped, steel-clad fuel segments. The heavy metals are electrotransported from anodic dissolution baskets to solid and liquid cathodes in a molten salt electrolyte (LiCl-KCI) at 500 degrees C. Uranium is recovered on a solid cathode mandrel, while a uranium-plutonium mixture is recovered in a liquid cadmium cathode. The anode configuration consists of four baskets mounted on an anode shaft. These baskets provide parallel circuits in the electrolyte and salt flow through the chopped fuelbed as the baskets are rotated. The baskets for the engineering-scale tests were sized to contain up to 2.5 kg of heavy metal. Anodic dissolution of 10 kg batches of chopped, steel-clad simulated tuel (U-10% Zr and U-Zr-Fs alloy) was demonstrated

  14. Solid oxide fuel cell bi-layer anode with gadolinia-doped ceria for utilization of solid carbon fuel

    Energy Technology Data Exchange (ETDEWEB)

    Kellogg, Isaiah D. [Department of Mechanical and Aerospace Engineering, Missouri University of Science and Technology, 290A Toomey Hall, 400 West 13th Street, Rolla, MO 65409 (United States); Department of Materials Science and Engineering, Missouri University of Science and Technology, 223 McNutt Hall, 1400 N. Bishop, Rolla, MO 65409 (United States); Koylu, Umit O. [Department of Mechanical and Aerospace Engineering, Missouri University of Science and Technology, 290A Toomey Hall, 400 West 13th Street, Rolla, MO 65409 (United States); Dogan, Fatih [Department of Materials Science and Engineering, Missouri University of Science and Technology, 223 McNutt Hall, 1400 N. Bishop, Rolla, MO 65409 (United States)

    2010-11-01

    Pyrolytic carbon was used as fuel in a solid oxide fuel cell (SOFC) with a yttria-stabilized zirconia (YSZ) electrolyte and a bi-layer anode composed of nickel oxide gadolinia-doped ceria (NiO-GDC) and NiO-YSZ. The common problems of bulk shrinkage and emergent porosity in the YSZ layer adjacent to the GDC/YSZ interface were avoided by using an interlayer of porous NiO-YSZ as a buffer anode layer between the electrolyte and the NiO-GDC primary anode. Cells were fabricated from commercially available component powders so that unconventional production methods suggested in the literature were avoided, that is, the necessity of glycine-nitrate combustion synthesis, specialty multicomponent oxide powders, sputtering, or chemical vapor deposition. The easily-fabricated cell was successfully utilized with hydrogen and propane fuels as well as carbon deposited on the anode during the cyclic operation with the propane. A cell of similar construction could be used in the exhaust stream of a diesel engine to capture and utilize soot for secondary power generation and decreased particulate pollution without the need for filter regeneration. (author)

  15. OPTIMIZATION OF THE CATHODE LONG-TERM STABILITY IN MOLTEN CARBONATE FUEL CELLS: EXPERIMENTAL STUDY AND MATHEMATICAL MODELING

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Ralph E. White

    2001-03-31

    SS 304 was encapsulated with thin layers of Co-Ni by an electroless deposition process. The corrosion behavior of SS304 and Co-Ni-SS304 was investigated in molten carbonate under cathode gas atmosphere with electrochemical and surface characterization tools. Surface modification of SS304 reduced the dissolution of chromium and nickel into the molten carbonate melt. Composition of the corrosion scale formed in case of Co-Ni-SS304 is different from SS304 and shows the presence of Co and Ni oxides while the latter shows the presence of lithium ferrite. Polarization resistance for oxygen reduction reaction and conductivity of corrosion values for the corrosion scales were obtained using impedance analysis and current-potential plots. The results indicated lower polarization resistance for oxygen reduction reaction in the case of Co-Ni-SS304 when compared to SS304. Also, the conductivity of the corrosion scales was considerably higher in case of Co-Ni-SS304 than the SS304. This study shows that modifying the current collector surface with Co-Ni coatings leads to the formation of oxide scales with improved barrier properties and electronic conductivity.

  16. Study of a molten carbonate fuel cell combined heat, hydrogen and power system: Energy analysis

    International Nuclear Information System (INIS)

    Agll, Abdulhakim Amer A.; Hamad, Yousif M.; Hamad, Tarek A.; Thomas, Mathew; Bapat, Sushrut; Martin, Kevin B.; Sheffield, John W.

    2013-01-01

    Countries around the world are trying to use alternative fuels and renewable energy to reduce the energy consumption and greenhouse gas emissions. Biogas contains methane is considered a potential source of clean renewable energy. This paper discusses the design of a combined heat, hydrogen and power system, which generated by methane with use of Fuelcell, for the campus of Missouri University of Science and Technology located in Rolla, Missouri, USA. An energy flow and resource availability study was performed to identify sustainable type and source of feedstock needed to run the Fuelcell at its maximum capacity. FuelCell Energy's DFC1500 unit (a molten carbonate Fuelcell) was selected as the Fuelcell for the tri-generation (heat, hydrogen and electric power) system. This tri-generation system provides electric power to the campus, thermal energy for heating the anaerobic digester, and hydrogen for transportation, backup power and other applications on the campus. In conclusion, the combined heat, hydrogen and power system reduces fossil fuel usage, and greenhouse gas emissions at the university campus. -- Highlights: • Combined heat, hydrogen and power (CHHP) using a molten carbonate fuel cell. • Energy saving and alternative fuel of the products are determined. • Energy saving is increased when CHHP technology is implemented. • CHHP system reduces the greenhouse gas emissions and fuel consumption

  17. A validated dynamic model of the first marine molten carbonate fuel cell

    International Nuclear Information System (INIS)

    Ovrum, E.; Dimopoulos, G.

    2012-01-01

    In this work we present a modular, dynamic and multi-dimensional model of a molten carbonate fuel cell (MCFC) onboard the offshore supply vessel “Viking Lady” serving as an auxiliary power unit. The model is able to capture detailed thermodynamic, heat transfer and electrochemical reaction phenomena within the fuel cell layers. The model has been calibrated and validated with measured performance data from a prototype installation onboard the vessel. The model is able to capture detailed thermodynamic, heat transfer and electrochemical reaction phenomena within the fuel cell layers. The model has been calibrated and validated with measured performance data from a prototype installation onboard the offshore supply vessel. The calibration process included parameter identification, sensitivity analysis to identify the critical model parameters, and iterative calibration of these to minimize the overall prediction error. The calibrated model has a low prediction error of 4% for the operating range of the cell, exhibiting at the same time a physically sound qualitative behavior in terms of thermodynamic heat transfer and electrochemical phenomena, both on steady-state and transient operation. The developed model is suitable for a wide range of studies covering the aspects of thermal efficiency, performance, operability, safety and endurance/degradation, which are necessary to introduce fuel cells in ships. The aim of this MCFC model is to aid to the introduction, design, concept approval and verification of environmentally friendly marine applications such as fuel cells, in a cost-effective, fast and safe manner. - Highlights: ► We model the first marine molten carbonate fuel cell auxiliary power unit. ► The model is distributed spatially and models both steady state and transients. ► The model is validated against experimental data. ► The paper illustrates how the model can be used in safety and reliability studies.

  18. Synthesis and photocatalytic properties of graphitic carbon nitride nanofibers using porous anodic alumina templates

    Science.gov (United States)

    Suchitra, S. M.; Udayashankar, N. K.

    2017-12-01

    In the present study, we describe an effective method for the synthesis of Graphitic carbon nitride (GCN) nanostructures using porous anodic alumina (AAO) membrane as template by simple thermal condensation of cyanamide. Synthesized nanostructure was fully analysed by various techniques to detect its crystalline nature, morphology, luminescent properties followed by the evaluation of its photocatalytic activity in the degradation of Methylene blue dye. Structural analysis of synthesized GCNNF was systematically carried out using x-ray powder diffraction (XRD) and scanning electron microscope (SEM), and. The results confirmed the growth of GCN inside the nanochannels of anodic alumina templates. Luminescent properties of GCNNF were studied using photoluminescence (PL) spectroscopy. PL analysis showed the presence of a strong emission peak in the wavelength range of 350-600 nm in blue region. GCNNF displays higher photocatalytic performance in the photodegradation of methylene blue compare to the bulk GCN. Highlights 1. In the present paper, we report the synthesis of graphitic carbon nitride nanofibers (GCNNF) using porous anodic aluminium oxide membranes as templates through thermal condensation of cyanamide at 500 °C. 2. The synthesis of Graphitic carbon nitride nanofibers using porous andic alumina template is the efficient approach for increasing crystallinity and surface area. 3. The high surface area of graphitic carbon nitride nanofibers has a good impact on novel optical and photocatalytic properties of the bulkGCN. 4. AAO templating of GCN is one of the versatile method to produce tailorable GCN nanostructures with higher surface area and less number of structural defects. 5. Towards photocatalytic degradation of dyes, the tuning of physical properties is very essential thing hence we are succeeded in achieving better catalytic performance of GCN nanostructures by making use of AAO templates.

  19. Quantitative Analysis of Oxygen Gas Exhausted from Anode through In Situ Measurement during Electrolytic Reduction

    Directory of Open Access Journals (Sweden)

    Eun-Young Choi

    2017-01-01

    Full Text Available Quantitative analysis by in situ measurement of oxygen gas evolved from an anode was employed to monitor the progress of electrolytic reduction of simulated oxide fuel in a molten Li2O–LiCl salt. The electrolytic reduction of 0.6 kg of simulated oxide fuel was performed in 5 kg of 1.5 wt.% Li2O–LiCl molten salt at 650°C. Porous cylindrical pellets of simulated oxide fuel were used as the cathode by loading a stainless steel wire mesh cathode basket. A platinum plate was employed as the anode. The oxygen gas evolved from the anode was exhausted to the instrumentation for in situ measurement during electrolytic reduction. The instrumentation consisted of a mass flow controller, pump, wet gas meter, and oxygen gas sensor. The oxygen gas was successfully measured using the instrumentation in real time. The measured volume of the oxygen gas was comparable to the theoretically calculated volume generated by the charge applied to the simulated oxide fuel.

  20. R and D of On-line Reprocessing Technology for Molten-Salt Reactor Systems

    International Nuclear Information System (INIS)

    Uhlir, Jan; Tulackova, Radka; Chuchvalcova Bimova, Karolina

    2006-01-01

    The Molten Salt Reactor (MSR) represents one of promising future nuclear reactor concept included in the Generation IV reactors family. The reactor can be operated as the thorium breeder or as the actinide transmuter. However, the future deployment of Molten-Salt Reactors will be significantly dependent on the successful mastering of advanced reprocessing technologies dedicated to their fuel cycle. Here the on-line reprocessing technology connected with the fuel circuit of MSR is of special importance because the reactor cannot be operated for a long run without the fuel salt clean-up. Generally, main MSR reprocessing technologies are pyrochemical, majority of them are fluoride technologies. The proposed flow-sheets of MSR on-line reprocessing are based on a combination of molten-salt / liquid metal extraction and electro-separation processes, which can be added to the gas extraction process already verified during the MSRE project in ORNL. The crucial separation method proposed for partitioning of actinides from fission products is based on successive Anodic dissolution and Cathodic deposition processes in molten fluoride media. (authors)

  1. Porous Si spheres encapsulated in carbon shells with enhanced anodic performance in lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hui; Wu, Ping, E-mail: zjuwuping@njnu.edu.cn; Shi, Huimin; Lou, Feijian; Tang, Yawen; Zhou, Tongge; Zhou, Yiming, E-mail: zhouyiming@njnu.edu.cn; Lu, Tianhong

    2014-07-01

    Highlights: • In situ magnesiothermic reduction route for the formation of porous Si@C spheres. • Unique microstructural characteristics of both porous sphere and carbon matrix. • Enhanced anodic performance in term of cycling stability for lithium-ion batteries. - Abstract: A novel type of porous Si–C micro/nano-hybrids, i.e., porous Si spheres encapsulated in carbon shells (porous Si@C spheres), has been constructed through the pyrolysis of polyvinylidene fluoride (PVDF) and subsequent magnesiothermic reduction methodology by using SiO{sub 2} spheres as precursors. The as-synthesized porous Si@C spheres have been applied as anode materials for lithium-ion batteries (LIBs), and exhibit enhanced anodic performance in term of cycling stability compared with bare Si spheres. For example, the porous Si@C spheres are able to exhibit a high reversible capacity of 900.0 mA h g{sup −1} after 20 cycles at a current density of 0.05 C (1 C = 4200 mA g{sup −1}), which is much higher than that of bare Si spheres (430.7 mA h g{sup −1})

  2. Phase III Advanced Anodes and Cathodes Utilized in Energy Efficient Aluminum Production Cells; FINAL

    International Nuclear Information System (INIS)

    Christini, R.A.; Dawless, R.K.; Ray, S.P.; Weirauch, D.A. Jr.

    2001-01-01

    During Phase I of the present program, Alcoa developed a commercial cell concept that has been estimated to save 30% of the energy required for aluminum smelting. Phase ii involved the construction of a pilot facility and operation of two pilots. Phase iii of the Advanced Anodes and Cathodes Program was aimed at bench experiments to permit the resolution of certain questions to be followed by three pilot cells. All of the milestones related to materials, in particular metal purity, were attained with distinct improvements over work in previous phases of the program. NiO additions to the ceramic phase and Ag additions to the Cu metal phase of the cermet improved corrosion resistance sufficiently that the bench scale pencil anodes met the purity milestones. Some excellent metal purity results have been obtained with anodes of the following composition: Further improvements in anode material composition appear to be dependent on a better understanding of oxide solubilities in molten cryolite. For that reason, work was commissioned with an outside consultant to model the MeO - cryolite systems. That work has led to a better understanding of which oxides can be used to substitute into the NiO-Fe2O3 ceramic phase to stabilize the ferrites and reduce their solubility in molten cryolite. An extensive number of vertical plate bench electrolysis cells were run to try to find conditions where high current efficiencies could be attained. TiB2-G plates were very inconsistent and led to poor wetting and drainage. Pure TiB2 did produce good current efficiencies at small overlaps (shadowing) between the anodes and cathodes. This bench work with vertical plate anodes and cathodes reinforced the importance of good cathode wetting to attain high current efficiencies. Because of those conclusions, new wetting work was commissioned and became a major component of the research during the third year of Phase III. While significant progress was made in several areas, much work needs to be

  3. Carbon-Encapsulated Co3O4 Nanoparticles as Anode Materials with Super Lithium Storage Performance

    Science.gov (United States)

    Leng, Xuning; Wei, Sufeng; Jiang, Zhonghao; Lian, Jianshe; Wang, Guoyong; Jiang, Qing

    2015-11-01

    A high-performance anode material for lithium storage was successfully synthesized by glucose as carbon source and cobalt nitrate as Co3O4 precursor with the assistance of sodium chloride surface as a template to reduce the carbon sheet thickness. Ultrafine Co3O4 nanoparticles were homogeneously embedded in ultrathin porous graphitic carbon in this material. The carbon sheets, which have large specific surface area, high electronic conductivity, and outstanding mechanical flexibility, are very effective to keep the stability of Co3O4 nanoparticales which has a large capacity. As a consequence, a very high reversible capacity of up to 1413 mA h g-1 at a current density of 0.1 A g-1 after 100 cycles, a high rate capability (845, 560, 461 and 345 mA h g-1 at 5, 10, 15 and 20 C, respectively, 1 C = 1 A g-1), and a superior cycling performance at an ultrahigh rate (760 mA h g-1 at 5 C after 1000 cycles) are achieved by this lithium-ion-battery anode material.

  4. Growth control of carbon nanotubes using by anodic aluminum oxide nano templates.

    Science.gov (United States)

    Park, Yong Seob; Choi, Won Seek; Yi, Junsin; Lee, Jaehyeong

    2014-05-01

    Anodic Aluminum Oxide (AAO) template prepared in acid electrolyte possess regular and highly anisotropic porous structure with pore diameter range from five to several hundred nanometers, and with a density of pores ranging from 10(9) to 10(11) cm(-2). AAO can be used as microfilters and templates for the growth of CNTs and metal or semiconductor nanowires. Varying anodizing conditions such as temperature, electrolyte, applied voltage, anodizing and widening time, one can control the diameter, the length, and the density of pores. In this work, we deposited Al thin film by radio frequency magnetron sputtering method to fabricate AAO nano template and synthesized multi-well carbon nanotubes on a glass substrate by microwave plasma-enhanced chemical vapor deposition (MPECVD). AAO nano-porous templates with various pore sizes and depths were introduced to control the dimension and density of CNT arrays. The AAO nano template was synthesize on glass by two-step anodization technique. The average diameter and interpore distance of AAO nano template are about 65 nm and 82 nm. The pore density and AAO nano template thickness are about 2.1 x 10(10) pores/cm2 and 1 microm, respectively. Aligned CNTs on the AAO nano template were synthesized by MPECVD at 650 degrees C with the Ni catalyst layer. The length and diameter of CNTs were grown 2 microm and 50 nm, respectively.

  5. Atmospheric pressure arc discharge with ablating graphite anode

    International Nuclear Information System (INIS)

    Nemchinsky, V A; Raitses, Y

    2015-01-01

    The anodic carbon arc discharge is used to produce carbon nanoparticles. Recent experiments with the carbon arc at atmospheric pressure helium demonstrated the enhanced ablation rate for narrow graphite anodes resulting in high deposition rates of carbonaceous products on the copper cathode (Fetterman et al 2008 Carbon 46 1322–6). The proposed model explains these results with interconnected steady-state models of the cathode and the anode processes. When considering cathode functioning, the model predicts circulation of the particles in the near-cathode region: evaporation of the cathode material, ionization of evaporated atoms and molecules in the near-cathode plasma, return of the resulting ions to the cathode, surface recombination of ions and electrons followed again by cathode evaporation etc. In the case of the low anode ablation rate, the ion acceleration in the cathode sheath provides the major cathode heating mechanism. In the case of an intensive anode ablation, an additional cathode heating is due to latent fusion heat of the atomic species evaporated from the anode and depositing at the cathode. Using the experimental arc voltage as the only input discharge parameter, the model allows us to calculate the anode ablation rate. A comparison of the results of calculations with the available experimental data shows reasonable agreement. (paper)

  6. Atmospheric pressure arc discharge with ablating graphite anode

    Science.gov (United States)

    Nemchinsky, V. A.; Raitses, Y.

    2015-06-01

    The anodic carbon arc discharge is used to produce carbon nanoparticles. Recent experiments with the carbon arc at atmospheric pressure helium demonstrated the enhanced ablation rate for narrow graphite anodes resulting in high deposition rates of carbonaceous products on the copper cathode (Fetterman et al 2008 Carbon 46 1322-6). The proposed model explains these results with interconnected steady-state models of the cathode and the anode processes. When considering cathode functioning, the model predicts circulation of the particles in the near-cathode region: evaporation of the cathode material, ionization of evaporated atoms and molecules in the near-cathode plasma, return of the resulting ions to the cathode, surface recombination of ions and electrons followed again by cathode evaporation etc. In the case of the low anode ablation rate, the ion acceleration in the cathode sheath provides the major cathode heating mechanism. In the case of an intensive anode ablation, an additional cathode heating is due to latent fusion heat of the atomic species evaporated from the anode and depositing at the cathode. Using the experimental arc voltage as the only input discharge parameter, the model allows us to calculate the anode ablation rate. A comparison of the results of calculations with the available experimental data shows reasonable agreement.

  7. Synthesis and electrochemical performance of ruthenium oxide-coated carbon nanofibers as anode materials for lithium secondary batteries

    Energy Technology Data Exchange (ETDEWEB)

    Hyun, Yura; Choi, Jin-Yeong [Department of Chemistry, Keimyung University (Korea, Republic of); Park, Heai-Ku [Department of Chemical Engineering, Keimyung University (Korea, Republic of); Lee, Chang-Seop, E-mail: surfkm@kmu.ac.kr [Department of Chemistry, Keimyung University (Korea, Republic of)

    2016-12-01

    Highlights: • Ruthenium oxide (RuO{sub 2}) coated carbon nanofibers (CNFs) on Ni foam were synthesized by chemical vapor deposition method and applied as anode materials of Li secondary batteries. • When RuO{sub 2}/CNFs/Ni foam was used as the anode material, initial capacity was improved from 276 mAh/g to 494 mAh/g with retention rate of 47.4% after 30 cycles. - Abstract: In this study, ruthenium oxide (RuO{sub 2}) coated carbon nanofibers (CNFs) were synthesized and applied as anode materials of Li secondary batteries. The CNFs were grown on Ni foam via chemical vapor deposition (CVD) method after CNFs/Ni foam was put into the 0.01 M RuCl{sub 3} solution. The ruthenium oxide-coated CNFs/Ni foam was dried in a dryer at 80 °C. The morphologies, compositions, and crystal quality of RuO{sub 2}/CNFs/Ni foam were characterized by SEM, EDS, XRD, Raman spectroscopy, and XPS. The electrochemical characteristics of RuO{sub 2}/CNFs/Ni foam as anode of Li secondary batteries were investigated using three-electrode cell. The RuO{sub 2}/CNFs/Ni foam was directly employed as a working electrode without any binder, and lithium foil was used as the counter and reference electrodes. LiClO{sub 4} (1 M) was employed as electrolyte and dissolved in a mixture of propylene carbonate (PC): ethylene carbonate (EC) in a 1:1 volume ratio. The galvanostatic charge/discharge cycling and cyclic voltammetry measurements were carried out at room temperature by using a battery tester. In particular, synthesized RuO{sub 2}/CNFs/Ni foam showed the highest retention rate (47.4%). The initial capacity (494 mAh/g) was reduced to 234 mAh/g after 30 cycles.

  8. Synthesis and electrochemical performance of ruthenium oxide-coated carbon nanofibers as anode materials for lithium secondary batteries

    International Nuclear Information System (INIS)

    Hyun, Yura; Choi, Jin-Yeong; Park, Heai-Ku; Lee, Chang-Seop

    2016-01-01

    Highlights: • Ruthenium oxide (RuO_2) coated carbon nanofibers (CNFs) on Ni foam were synthesized by chemical vapor deposition method and applied as anode materials of Li secondary batteries. • When RuO_2/CNFs/Ni foam was used as the anode material, initial capacity was improved from 276 mAh/g to 494 mAh/g with retention rate of 47.4% after 30 cycles. - Abstract: In this study, ruthenium oxide (RuO_2) coated carbon nanofibers (CNFs) were synthesized and applied as anode materials of Li secondary batteries. The CNFs were grown on Ni foam via chemical vapor deposition (CVD) method after CNFs/Ni foam was put into the 0.01 M RuCl_3 solution. The ruthenium oxide-coated CNFs/Ni foam was dried in a dryer at 80 °C. The morphologies, compositions, and crystal quality of RuO_2/CNFs/Ni foam were characterized by SEM, EDS, XRD, Raman spectroscopy, and XPS. The electrochemical characteristics of RuO_2/CNFs/Ni foam as anode of Li secondary batteries were investigated using three-electrode cell. The RuO_2/CNFs/Ni foam was directly employed as a working electrode without any binder, and lithium foil was used as the counter and reference electrodes. LiClO_4 (1 M) was employed as electrolyte and dissolved in a mixture of propylene carbonate (PC): ethylene carbonate (EC) in a 1:1 volume ratio. The galvanostatic charge/discharge cycling and cyclic voltammetry measurements were carried out at room temperature by using a battery tester. In particular, synthesized RuO_2/CNFs/Ni foam showed the highest retention rate (47.4%). The initial capacity (494 mAh/g) was reduced to 234 mAh/g after 30 cycles.

  9. Fe_3C@carbon nanocapsules/expanded graphite as anode materials for lithium ion batteries

    International Nuclear Information System (INIS)

    Huang, You-Guo; Lin, Xi-Le; Zhang, Xiao-Hui; Pan, Qi-Chang; Yan, Zhi-Xiong; Wang, Hong-Qiang; Chen, Jian-Jun; Li, Qing-Yu

    2015-01-01

    ABSTRACT: Fe_3C@carbonnanocapsules(*)/expanded graphite composite was successfully prepared by a new and facile method, including mix of starting materials and heat treatment of the precursor. It is featured by unique 3-D structure, where expanded graphite acts as scaffold to ensure a continuous entity, and Fe_3C particles coated by carbon nanocapsules are embedded intimately. The Fe_3C nanoparticles encased in carbon nanocapsules act as catalyst in the modification of SEI film during the cycles. The interesting 3-D architecture which aligns the conductivity paths in the planar direction with expanded graphite and in the axial direction with carbon nanocapsules minimizes the resistance and enhances the reversible capacity. The prepared composite exhibits a high reversible capacity and excellent rate performance as an anode material for lithium ion batteries. The composite maintains a reversible capacity of 1226.2 mAh/g after 75 cycles at 66 mA/g. When the current density increases to 200 mA/g, the reversible capacity maintains 451.5 mAh/g. The facile synthesis method and excellent electrochemical performances make the composite expected to be one of the most potential anode material for lithium ion batteries.

  10. Synthesis and electrochemical performances of amorphous carbon-coated Sn-Sb particles as anode material for lithium-ion batteries

    International Nuclear Information System (INIS)

    Wang Zhong; Tian Wenhuai; Liu Xiaohe; Yang Rong; Li Xingguo

    2007-01-01

    The amorphous carbon coating on the Sn-Sb particles was prepared from aqueous glucose solutions using a hydrothermal method. Because the outer layer carbon of composite materials is loose cotton-like and porous-like, it can accommodate the expansion and contraction of active materials to maintain the stability of the structure, and hinder effectively the aggregation of nano-sized alloy particles. The as-prepared composite materials show much improved electrochemical performances as anode materials for lithium-ion batteries compared with Sn-Sb alloy and carbon alone. This amorphous carbon-coated Sn-Sb particle is extremely promising anode materials for lithium secondary batteries and has a high potentiality in the future use. - Graphical abstract: The amorphous carbon coating on the Sn-Sb particles was prepared from aqueous glucose solutions using a hydrothermal method. Because the outer layer carbon of composite materials is loose cotton-like and porous-like, it can accommodate the expansion and contraction of active materials to maintain the stability of the structure, and hinder effectively the aggregation of nano-sized alloy particles

  11. Silicon-Encapsulated Hollow Carbon Nanofiber Networks as Binder-Free Anodes for Lithium Ion Battery

    Directory of Open Access Journals (Sweden)

    Ding Nan

    2014-01-01

    Full Text Available Silicon-encapsulated hollow carbon nanofiber networks with ample space around the Si nanoparticles (hollow Si/C composites were successfully synthesized by dip-coating phenolic resin onto the surface of electrospun Si/PVA nanofibers along with the subsequent solidification and carbonization. More importantly, the structure and Si content of hollow Si/C composite nanofibers can be effectively tuned by merely varying the concentration of dip solution. As-synthesized hollow Si/C composites show excellent electrochemical performance when they are used as binder-free anodes for Li-ion batteries (LIBs. In particular, when the concentration of resol/ethanol solution is 3.0%, the product exhibits a large capacity of 841 mAh g−1 in the first cycle, prominent cycling stability, and good rate capability. The discharge capacity retention of it was ~90%, with 745 mAh g−1 after 50 cycles. The results demonstrate that the hollow Si/C composites are very promising as alternative anode candidates for high-performance LIBs.

  12. Improving the Tribological Properties of Spark-Anodized Titanium by Magnetron Sputtered Diamond-Like Carbon

    Directory of Open Access Journals (Sweden)

    Zhaoxiang Chen

    2018-02-01

    Full Text Available Spark-anodization of titanium can produce adherent and wear-resistant TiO2 film on the surface, but the spark-anodized titanium has lots of surface micro-pores, resulting in an unstable and high friction coefficient against many counterparts. In this study, the diamond-like carbon (DLC was introduced into the micro-pores of spark-anodized titanium by the magnetron sputtering technique and a TiO2/DLC composite coating was fabricated. The microstructure and tribological properties of TiO2/DLC composite coating were investigated and compared with the anodic TiO2 mono-film and DLC mono-film. Results show that the DLC deposition significantly decreased the surface roughness and porosity of spark-anodized titanium. The fabricated TiO2/DLC composite coating exhibited a more stable and much lower friction coefficient than anodic TiO2 mono-film. Although the friction coefficient of the composite coating and the DLC mono-film was similar under both light load and heavy load conditions, the wear life of the composite coating was about 43% longer than that of DLC mono-film under heavy load condition. The wear rate of titanium with protective composite coating was much lower than that of titanium with DLC mono-film. The superior low friction coefficient and wear rate of the TiO2/DLC composite coating make it a good candidate as protective coating on titanium alloys.

  13. Matrix coatings based on anodic alumina with carbon nanostructures in the pores

    Science.gov (United States)

    Gorokh, G. G.; Pashechko, M. I.; Borc, J. T.; Lozovenko, A. A.; Kashko, I. A.; Latos, A. I.

    2018-03-01

    The nanoporous anodic alumina matrixes thickness of 1.5 mm and pore sizes of 45, 90 and 145 nm were formed on Si substrates. The tubular carbon nanostructures were synthesized into the matrixes pores by pyrolysis of fluid hydrocarbon xylene with 1% ferrocene. The structure and composition of the matrix coatings were examined by scanning electron microscopy, Auger analysis and Raman spectroscopy. The carbon nanostructures completely filled the pores of templates and uniformly covered the tops. The structure of carbon nanostructures corresponded to the structure of multiwall carbon nanotubes. Investigations of mechanical and tribological properties of nanostructured oxide-carbon composite performed by scratching and nanoindentation showed nonlinear dependencies of the frictional force, penetration depth of the cantilever, hardness and plane strain modulus on the load. It was found that the microhardness of the samples increases with reduced of alumina pore diameter, and the penetration depth of the cantilever into the film grows with carbon nanostructures size. The results showed the high mechanical strength of nanostructured oxide-carbon composite.

  14. Nickel-based anode with water storage capability to mitigate carbon deposition for direct ethanol solid oxide fuel cells.

    Science.gov (United States)

    Wang, Wei; Su, Chao; Ran, Ran; Zhao, Bote; Shao, Zongping; Tade, Moses O; Liu, Shaomin

    2014-06-01

    The potential to use ethanol as a fuel places solid oxide fuel cells (SOFCs) as a sustainable technology for clean energy delivery because of the renewable features of ethanol versus hydrogen. In this work, we developed a new class of anode catalyst exemplified by Ni+BaZr0.4Ce0.4Y0.2O3 (Ni+BZCY) with a water storage capability to overcome the persistent problem of carbon deposition. Ni+BZCY performed very well in catalytic efficiency, water storage capability and coking resistance tests. A stable and high power output was well maintained with a peak power density of 750 mW cm(-2) at 750 °C. The SOFC with the new robust anode performed for seven days without any sign of performance decay, whereas SOFCs with conventional anodes failed in less than 2 h because of significant carbon deposition. Our findings indicate the potential applications of these water storage cermets as catalysts in hydrocarbon reforming and as anodes for SOFCs that operate directly on hydrocarbons. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Solar gasification of biomass: design and characterization of a molten salt gasification reactor

    Science.gov (United States)

    Hathaway, Brandon Jay

    The design and implementation of a prototype molten salt solar reactor for gasification of biomass is a significant milestone in the development of a solar gasification process. The reactor developed in this work allows for 3 kWth operation with an average aperture flux of 1530 suns at salt temperatures of 1200 K with pneumatic injection of ground or powdered dry biomass feedstocks directly into the salt melt. Laboratory scale experiments in an electrically heated reactor demonstrate the benefits of molten salt and the data was evaluated to determine the kinetics of pyrolysis and gasification of biomass or carbon in molten salt. In the presence of molten salt overall gas yields are increased by up to 22%; pyrolysis rates double due to improved heat transfer, while carbon gasification rates increase by an order of magnitude. Existing kinetic models for cellulose pyrolysis fit the data well, while carbon gasification in molten salt follows kinetics modeled with a 2/3 order shrinking-grain model with a pre-exponential factor of 1.5*106 min-1 and activation energy of 158 kJ/mol. A reactor concept is developed based around a concentric cylinder geometry with a cavity-style solar receiver immersed within a volume of molten carbonate salt. Concentrated radiation delivered to the cavity is absorbed in the cavity walls and transferred via convection to the salt volume. Feedstock is delivered into the molten salt volume where biomass gasification reactions will be carried out producing the desired product gas. The features of the cavity receiver/reactor concept are optimized based on modeling of the key physical processes. The cavity absorber geometry is optimized according to a parametric survey of radiative exchange using a Monte Carlo ray tracing model, resulting in a cavity design that achieves absorption efficiencies of 80%-90%. A parametric survey coupling the radiative exchange simulations to a CFD model of molten salt natural convection is used to size the annulus

  16. Effects of coal-derived trace species on the performance of molten carbonate fuel cells. Topical report on thermochemical studies

    Energy Technology Data Exchange (ETDEWEB)

    Pigeaud, A.

    1991-10-01

    The overall objective of the present study was to determine in detail the interaction effects of 10 simultaneously present, coal-gas contaminants, both on each other and on components of the Carbonate Fuel Cell. The primary goal was to assess underlying chemistries and reaction mechanisms which may cause decay in fuel cell performance or endurance as a result of both physics-chemical and/or mechanical interactions with the cell components and internal fuel cell parts. It was found, both from theory and cell test evidence, that trace contaminant interactions may occur with: Fuel-cell Electrodes (e.g., in this study with the Ni-anode), Lithium/Potassium Carbonate Electrolyte, Nickel and SS-Hardware, and by Mechanical Obstruction of Gas Flow in the Anode Plenum.

  17. Actuation method of molten carbonate fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Yasuhiko; Kimoto, Mamoru; Murakami, Shuzo; Furukawa, Nobuhiro

    1987-10-17

    A molten carbonate fuel cell uses reformed gas of crude fuel as fuel gas, but in this gas, CO/sub 2/ is contained in addition to H/sub 2/ and CO which participate the reaction in its fuel electrode. In order to make the reaction of the cell by these gases smoothly, CO/sub 2/ in the exhaust gas from the fuel electrode must be introduced efficiently to its oxygen electrode, however since unreacted H/sub 2/ and CO are contained in the above exhaust gas, they are oxidated and burned once in a boiler and transformed into H/sub 2/O (steam) and CO/sub 2/, then CO/sub 2/ generated in the fuel electrode is added thereto, and afterwards these gases with the air are introduced into the oxygen electrode. However, since this method hinders the high power generation efficiency, in this invention, the exhaust gas from the fuel electrode which burns the reformed gas is introduced into separation chambers separated with CO/sub 2/ permselective membranes, and the mixture of CO/sub 2/ in the above exhaust gas separated with the aforementioned permeable membranes and the air is supplied to the oxygen electrode. At the same time, H/sub 2/ and CO in the above exhaust gas which were not separated with the above permeable membranes are recirculated to the above fuel electrode. (3 figs)

  18. High Surface Area Iridium Anodes and Melt Containers for Molten Oxide Electrolysis, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Direct electrochemical reduction of molten regolith is the most attractive method of oxygen production on the lunar surface, because no additional chemical reagents...

  19. SnSe/carbon nanocomposite synthesized by high energy ball milling as an anode material for sodium-ion and lithium-ion batteries

    International Nuclear Information System (INIS)

    Zhang, Zhian; Zhao, Xingxing; Li, Jie

    2015-01-01

    Graphical abstract: A homogeneous nanocomposite of SnSe and carbon black was synthesised by high energy ball milling and empolyed as an anode material for sodium-ion batteries (SIBs) and lithium-ion batteries (LIBs). The nanocomposite anode exhibits excellent electrochemical performances in both SIBs and LIBs. - Highlights: • A homogeneous nanocomposite of SnSe and carbon black was fabricated by high energy ball milling. • SnSe and carbon black are homogeneously mixed at the nanoscale level. • The SnSe/C anode exhibits excellent electrochemical performances in both SIBs and LIBs. - Abstract: A homogeneous nanocomposite of SnSe and carbon black, denoted as SnSe/C nanocomposite, was fabricated by high energy ball milling and empolyed as a high performance anode material for both sodium-ion batteries and lithium-ion batteries. The X-ray diffraction patterns, scanning electron microscopy and transmission electron microscopy observations confirmed that SnSe in SnSe/C nanocomposite was homogeneously distributed within carbon black. The nanocomposite anode exhibited enhanced electrochemical performances including a high capacity, long cycling behavior and good rate performance in both sodium-ion batteries (SIBs) and lithium-ion batteries (LIBs). In SIBs, an initial capacitiy of 748.5 mAh g −1 was obtained and was maintained well on cycling (324.9 mAh g −1 at a high current density of 500 mA g −1 in the 200 th cycle) with 72.5% retention of second cycle capacity (447.7 mAh g −1 ). In LIBs, high initial capacities of approximately 1097.6 mAh g −1 was obtained, and this reduced to 633.1 mAh g −1 after 100 cycles at 500 mA g −1

  20. Electrodeposited Germanium/Carbon Composite as an Anode Material for Lithium Ion Batteries

    International Nuclear Information System (INIS)

    Kim, Sang-Wan; Ngo, Duc Tung; Heo, Jaeyeong; Park, Choong-Nyeon; Park, Chan-Jin

    2017-01-01

    Highlights: • Electrodeposition was applied for the synthesis of Ge/C composite. • High coulombic efficiency of ∼85% in the first cycle was attained for Ge/C composite. • Full cell of Ge/C-LiCoO 2 exhibits excellent electrochemical performance, without pre-lithiation of Ge/C. - Abstract: We demonstrate the synthesis of nano Ge/C composite using a facile and cost-effective electrochemical deposition method, and its application as an anode material in Li-ion batteries. Nano Ge/C composite is electrodeposited directly on Cu foil in ethylene glycol containing GeCl 4 and carbon black. The Ge particles with an average size of ∼20 nm are uniformly covered with carbon. Compared with the pure Ge electrode, the Ge/C electrode exhibits a higher first reversible capacity of 1224 mA g −1 , and maintains a capacity of 1095 mAh g −1 at 0.1C over 50 cycles. Even at the high rate of 2C, the capacity of the Ge/C electrode is still high at 972 mAh g −1 . The presence of carbon black and pores in the Ge/C electrode improves the conductivity of the electrode, and mitigates the stress inside the electrode by supplying buffer volume, leading to the enhanced electrochemical characteristics of the electrode. Further, the full Li-ion cell composed of Ge/C anode and LiCoO 2 cathode exhibits good cyclability, rate capability, and coulombic efficiency.

  1. An in situ method of creating metal oxide–carbon composites and their application as anode materials for lithium-ion batteries

    KAUST Repository

    Yang, Zichao

    2011-01-01

    Transition metal oxides are actively investigated as anode materials for lithium-ion batteries (LIBs), and their nanocomposites with carbon frequently show better performance in galvanostatic cycling studies, compared to the pristine metal oxide. An in situ, scalable method for creating a variety of transition metal oxide-carbon nanocomposites has been developed based on free-radical polymerization and cross-linking of poly(acrylonitrile) in the presence of the metal oxide precursor containing vinyl groups. The approach yields a cross-linked polymer network, which uniformly incorporates nanometre-sized transition metal oxide particles. Thermal treatment of the organic-inorganic hybrid material produces nearly monodisperse metal oxide nanoparticles uniformly embedded in a porous carbon matrix. Cyclic voltammetry and galvanostatic cycling electrochemical measurements in a lithium half-cell are used to evaluate the electrochemical properties of a Fe3O 4-carbon composite created using this approach. These measurements reveal that when used as the anode in a lithium battery, the material exhibits stable cycling performance at both low and high current densities. We further show that the polymer/nanoparticle copolymerization approach can be readily adapted to synthesize metal oxide/carbon nanocomposites based on different particle chemistries for applications in both the anode and cathode of LIBs. © 2011 The Royal Society of Chemistry.

  2. Field emission properties of low-density carbon nanotubes prepared on anodic aluminum-oxide template

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Soo-Hwan [Samsung Advanced Institute of Technology, Suwon (Korea, Republic of); Lee, Kun-Hong [Pohang University of Science and Technology, Pohang (Korea, Republic of)

    2004-08-15

    Anodic aluminum-oxide (AAO) templates were fabricated by two-step anodizing an Al film. After the Co catalyst had been electrochemically deposited onto the bottom of the AAO template, carbon nanotubes (CNTs) were grown by using catalytic pyrolysis of C{sub 2}H{sub 2} and H{sub 2} at 650 .deg. C. Overgrowth of CNTs with low density on the AAO templates was observed. The field-emission measurements on the samples showed a turn-on field of 2.17 V/mum and a field enhancement factor of 5700. The emission pattern on a phosphor screen was quite homogeneous over the area at a relatively low electric field.

  3. Facile Synthesis of Highly Aligned Multiwalled Carbon Nanotubes from Polymer Precursors

    Directory of Open Access Journals (Sweden)

    Catherine Y. Han

    2009-01-01

    Full Text Available We report a facile one-step approach which involves no flammable gas, no catalyst, and no in situ polymerization for the preparation of well-aligned carbon nanotube array. A polymer precursor is placed on top of an anodized aluminum oxide (AAO membrane containing regular nanopore arrays, and slow heating under Ar flow allows the molten polymer to wet the template through adhesive force. The polymer spread into the nanopores of the template to form polymer nanotubes. Upon carbonization the resulting multi-walled carbon nanotubes duplicate the nanopores morphology precisely. The process is demonstrated for 230, 50, and 20 nm pore membranes. The synthesized carbon nanotubes are characterized with scanning/transmission electron microscopies, Raman spectroscopy, and resistive measurements. Convenient functionalization of the nanotubes with this method is demonstrated through premixing CoPt nanoparticles in the polymer precursors.

  4. Facile synthesis of highly aligned multiwalled carbon nanotubes from polymer precursors.

    Energy Technology Data Exchange (ETDEWEB)

    Han, C. Y.; Xiao, Z.-L.; Wang, H. H.; Lin, X.-M.; Trasobares, S.; Cook, R. E.; Richard J. Daley Coll.; Northern Illinois Univ.; Univ. de Cadiz

    2009-01-01

    We report a facile one-step approach which involves no flammable gas, no catalyst, and no in situ polymerization for the preparation of well-aligned carbon nanotube array. A polymer precursor is placed on top of an anodized aluminum oxide (AAO) membrane containing regular nanopore arrays, and slow heating under Ar flow allows the molten polymer to wet the template through adhesive force. The polymer spread into the nanopores of the template to form polymer nanotubes. Upon carbonization the resulting multi-walled carbon nanotubes duplicate the nanopores morphology precisely. The process is demonstrated for 230, 50, and 20 nm pore membranes. The synthesized carbon nanotubes are characterized with scanning/transmission electron microscopies, Raman spectroscopy, and resistive measurements. Convenient functionalization of the nanotubes with this method is demonstrated through premixing CoPt nanoparticles in the polymer precursors.

  5. Hollow carbon sphere/metal oxide nanocomposites anodes for lithium-ion batteries

    International Nuclear Information System (INIS)

    Wenelska, K.; Ottmann, A.; Schneider, P.; Thauer, E.; Klingeler, R.; Mijowska, E.

    2016-01-01

    HCS (Hollow carbon spheres) covered with metal oxide nanoparticles (SnO_2 and MnO_2, respectively) were successfully synthesized and investigated regarding their potential as anode materials for lithium-ion batteries. Raman spectroscopy shows a high degree of graphitization for the HCS host structure. The mesoporous nature of the nanocomposites is confirmed by Brunauer–Emmett–Teller analysis. For both metal oxides under study, the metal oxide functionalization of HCS yields a significant increase of electrochemical performance. The charge capacity of HCS/SnO_2 is 370 mA hg"−"1 after 45 cycles (266 mA hg"−"1 in HCS/MnO_2) which clearly exceeds the value of 188 mA hg"−"1 in pristine HCS. Remarkably, the data imply excellent long term cycling stability after 100 cycles in both cases. The results hence show that mesoporous HCS/metal oxide nanocomposites enable exploiting the potential of metal oxide anode materials in Lithium-ion batteries by providing a HCS host structure which is both conductive and stable enough to accommodate big volume change effects. - Highlights: • Strategy to synthesize hollow carbon spheres decorated by metal oxides nanoparticles. • High-performance of HCS/MOx storage as mesoporous hybrid material. • The results hence demonstrate high electrochemical activity of the HCS/MOx.

  6. Rational design of hierarchical ZnO@Carbon nanoflower for high performance lithium ion battery anodes

    Science.gov (United States)

    liu, Huichao; Shi, Ludi; Li, Dongzhi; Yu, Jiali; Zhang, Han-Ming; Ullah, Shahid; Yang, Bo; Li, Cuihua; Zhu, Caizhen; Xu, Jian

    2018-05-01

    The rational structure design and strong interfacial bonding are crucially desired for high performance zinc oxide (ZnO)/carbon composite electrodes. In this context, micro-nano secondary structure design and strong dopamine coating strategies are adopted for the fabrication of flower-like ZnO/carbon (ZnO@C nanoflowers) composite electrodes. The results show the ZnO@C nanoflowers (2-6 μm) are assembled by hierarchical ZnO nanosheets (∼27 nm) and continuous carbon framework. The micro-nano secondary architecture can facilitate the penetration of electrolyte, shorten lithium ions diffusion length, and hinder the aggregation of the nanosheets. Moreover, the strong chemical interaction between ZnO and coating carbon layer via C-Zn bond improves structure stability as well as the electronic conductivity. As a synergistic result, when evaluated as lithium ion batteries (LIBs) anode, the ZnO@C nanoflower electrodes show high reversible capacity of ca. 1200 mA h g-1 at 0.1 A g-1 after 80 cycles. As well as good long-cycling stability (638 and 420 mA h g-1 at 1 and 5 A g-1 after 500 cycles, respectively) and excellent rate capability. Therefore, this rational design of ZnO@C nanoflowers electrode is a promising anode for high-performance LIBs.

  7. Prelithiation of silicon-carbon nanotube anodes for lithium ion batteries by stabilized lithium metal powder (SLMP).

    Science.gov (United States)

    Forney, Michael W; Ganter, Matthew J; Staub, Jason W; Ridgley, Richard D; Landi, Brian J

    2013-09-11

    Stabilized lithium metal powder (SLMP) has been applied during battery assembly to effectively prelithiate high capacity (1500-2500 mAh/g) silicon-carbon nanotube (Si-CNT) anodes, eliminating the 20-40% first cycle irreversible capacity loss. Pressure-activation of SLMP is shown to enhance prelithiation and enable capacity matching between Si-CNT anodes and lithium nickel cobalt aluminum oxide (NCA) cathodes in full batteries with minimal added mass. The prelithiation approach enables high energy density NCA/Si-CNT batteries achieving >1000 cycles at 20% depth-of-discharge.

  8. Destruction of high explosives and wastes containing high explosives using the molten salt destruction process

    International Nuclear Information System (INIS)

    Upadhye, R.S.; Brummond, W.A.; Pruneda, C.O.

    1992-01-01

    This paper reports the Molten Salt Destruction (MSD) Process which has been demonstrated for the destruction of HE and HE-containing wastes. MSD has been used by Rockwell International and by Anti-Pollution Systems to destroy hazardous wastes. MSD converts the organic constituents (including the HE) of the waste into non-hazardous substances such as carbon dioxide, nitrogen and water. In the case of HE-containing mixed wastes, any actinides in the waste are retained in the molten salt, thus converting the mixed wastes into low-level wastes. (Even though the MSD process is applicable to mixed wastes, this paper will emphasize HE-treatment.) The destruction of HE is accomplished by introducing it, together with oxidant gases, into a crucible containing a molten salt, such as sodium carbonate, or a suitable mixture of the carbonates of sodium, potassium, lithium and calcium. The temperature of the molten salt can be between 400 to 900 degrees C. The combustible organic components of the waste react with oxygen to produce carbon dioxide, nitrogen and steam

  9. Effect of Carbon Coating on Li4TiO12 of Anode Material for Hybrid Capacitor.

    Science.gov (United States)

    Lee, Jong-Kyu; Lee, Byung-Gwan; Yoon, Jung-Rag

    2015-11-01

    The carbon-coated Li4Ti5O12 of anode material for hybrid capacitor was prepared by controlling carbonization time at 700 degrees C in nitrogen. With increasing of carbonization time, the discharge capacity and capacitance were decreased, while the equivalent series resistance was not changed remarkably. The rate capability and cycle performance of carbon-coated Li4Ti5O12 were larger than that of Li4Ti5O12. Carbon coating improved conductivity as well as Li-ion diffusion, and thus also resulted in good rate capabilities and cycle stability. The effects of carbon coating on the gas generation of hybrid capacitor were also discussed.

  10. Advances in molten salt electrochemistry towards future energy systems

    International Nuclear Information System (INIS)

    Ito, Yasuhiko

    2005-01-01

    This review article describes some selected novel molten salt electrochemical processes which have been created/developed by the author and his coworkers, with emphasis on the applications towards future energy systems. After showing a perspective of the applications of molten salt electrochemistry from the viewpoints of energy and environment, several selected topics are described in detail, which include nitride fuel cycle in a nuclear field, hydrogen energy system coupled with ammonia economy, thermally regenerative fuel cell systems, novel Si production process for solar cell and novel molten salt electrochemical processes for various energy and environment related functional materials including nitrides, rare earth-transition metal alloys, fine particles obtained by plasma-induced electrolysis, and carbon film. And finally, the author stresses again, the importance and potential of molten salt electrochemistry, and encourages young students, scientists and researchers to march in a procession hand in hand towards a bright future of molten salts. (author)

  11. Separation of calcium isotopes by counter-current electromigration in molten salts (1962)

    International Nuclear Information System (INIS)

    Menes, F.; Dirian, G.; Roth, E.

    1962-01-01

    The method of counter-current electromigration in molten salts has been applied to calcium bromide with an alkali metal bromide added to the cathode compartment. Enrichments on calcium-46 greater than a factor of two were obtained at the anode. The mass effect was found to be about 0.06. An estimation of the cost of energy for a process based on this method has been made. (authors) [fr

  12. Effect of oxide ion concentration on the electrochemical oxidation of carbon in molten LiCl

    International Nuclear Information System (INIS)

    Yun, J. W.; Choi, I. K.; Park, Y. S.; Kim, W. H.

    2001-01-01

    The continuous measurement of lithium oxide concentration was required in DOR (Direct Oxide Reduction) process, which converts spent nuclear fuel to metal form, for the reactivity monitor and effective control of the process. The concentration of lithium oxide was measured by the electrochemical method, which was based on the phenomenon that carbon atoms of glassy carbon electrode electrochemically react with oxygen ions of lithium oxide in molten LiCl medium. From the results of electrode polarization experiments, the trend of oxidation rate of carbon atoms was classified into two different regions, which were proportional and non-proportional ones, dependent on the amount of lithium oxide. Below about 2.5 wt % Li 2 O, as the carbon atom ionization rate was fast enough for reacting with diffusing lithium oxide to the surface of carbon electrode. In this concentration range, the oxidation rate of carbon atoms was controlled by the diffusion of lithium oxide, and the concentration of lithium oxide could be measured by electrochemical method. But, above 2.5 wt % Li 2 O, the oxidation rate of carbon atoms was controlled by the applied electrochemical potential, because the carbon atom ionization rate was suppressed by the huge amounts of diffusing Li 2 O. Above this concentration, the electrochemical method was not applicable to determine the concentration of lithium oxide

  13. Electrical and Mechanical Performance of Carbon Fiber-Reinforced Polymer Used as the Impressed Current Anode Material.

    Science.gov (United States)

    Zhu, Ji-Hua; Zhu, Miaochang; Han, Ningxu; Liu, Wei; Xing, Feng

    2014-07-24

    An investigation was performed by using carbon fiber-reinforced polymer (CFRP) as the anode material in the impressed current cathodic protection (ICCP) system of steel reinforced concrete structures. The service life and performance of CFRP were investigated in simulated ICCP systems with various configurations. Constant current densities were maintained during the tests. No significant degradation in electrical and mechanical properties was found for CFRP subjected to anodic polarization with the selected applied current densities. The service life of the CFRP-based ICCP system was discussed based on the practical reinforced concrete structure layout.

  14. A Simple Surface Modification of NiO Cathode with TiO2 Nano-Particles for Molten Carbonate Fuel Cells (MCFCs)

    International Nuclear Information System (INIS)

    Choi, Hee Seon; Kim, Keon; Yi, Cheolwoo

    2014-01-01

    The TiO 2 -modified Ni powders, prepared by the simple method (ball-milling and subsequent annealing) without resorting to any complex coating process, eventually form nickel titanate passive layer at high temperature. It as good corrosion resistance in molten carbonates media and higher electrical conductivity at high temperature. In addition, the modified cathode increases the degree of lithiation during the operation of MCFC. These positive effects provide a decrease in the internal resistance and improve the cell performance. Results obtained from this study can be applied to develop the surface modification of cathode materials and the performance of molten carbonate fuel cells. Molten carbonate fuel cells (MCFCs) are efficient energy conversion devices to convert chemical energy into electrical energy through the electrochemical reaction. Because of a lot of advantages of MCFC operated at high temperature, many researchers have been trying to apply it to large-scaled power generations, marine boats, and so on. Among various cathode materials, nickel oxide, NiO, is the most widely used cathode for MCFCs due to its stability and high electrical conductivity, but the degradation of cathode material, so-called NiO dissolution, prevents a long-term operation of MCFC. In order to overcome the drawback, numerous studies have been performed. One of the most useful ways to enhance the surface property and maintain the bulk property of the host materials is the surface modification. The most common modification method is coating and these coating procedures which need some complicated steps with the use of organic materials, but it restricts the large-scale fabrication. In this study, to improve the electrochemical performance, we have prepared an alternative MCFC cathode material, TiO 2 -modified NiO, by simple method without resorting to any complex coating process. Results obtained in this study can provide an effective way to mass-produce the cathode materials

  15. Development of electrolytic process in molten salt media for light rare-earth metals production. The metallic cerium electrodeposition

    International Nuclear Information System (INIS)

    Restivo, T.A.G.

    1994-01-01

    The development of molten salt process and the respective equipment aiming rare-earth metals recovery was described. In the present case, the liquid cerium metal electrodeposition in a molten electrolytes of cerium chloride and an equimolar mixture of sodium and potassium chlorides in temperatures near 800 C was studied. Due the high chemical reactivity of the rare-earth metals in the liquid state and their molten halides, an electrolytic cell was constructed with controlled atmosphere, graphite crucibles and anodes and a tungsten cathode. The electrolytic process variables and characteristics were evaluated upon the current efficiency and metallic product purity. Based on this evaluations, were suggested some alterations on the electrolytic reactor design and upon the process parameters. (author). 90 refs, 37 figs, 20 tabs

  16. Single-walled carbon nanotubes as stabilizing agents in red phosphorus Li-ion battery anodes

    KAUST Repository

    Smajic, Jasmin

    2017-08-16

    Phosphorus boasts extremely high gravimetric and volumetric capacities but suffers from poor electrochemical stability with significant capacity loss immediately after the first cycle. We propose to circumvent this issue by mixing amorphous red phosphorus with single-walled carbon nanotubes. Employing a non-destructive sublimation–deposition method, we have synthesized composites where the synergetic effect between red phosphorus and single-walled carbon nanotubes allows for a considerable improvement in the electrochemical stability of battery anodes. In contrast to the average 40% loss of capacity after 50 cycles for other phosphorus–carbon composites in the literature, our material shows losses of just 22% under analogous cycling conditions.

  17. Anode baking process optimization through computer modelling

    Energy Technology Data Exchange (ETDEWEB)

    Wilburn, D.; Lancaster, D.; Crowell, B. [Noranda Aluminum, New Madrid, MO (United States); Ouellet, R.; Jiao, Q. [Noranda Technology Centre, Pointe Claire, PQ (Canada)

    1998-12-31

    Carbon anodes used in aluminum electrolysis are produced in vertical or horizontal type anode baking furnaces. The carbon blocks are formed from petroleum coke aggregate mixed with a coal tar pitch binder. Before the carbon block can be used in a reduction cell it must be heated to pyrolysis. The baking process represents a large portion of the aluminum production cost, and also has a significant effect on anode quality. To ensure that the baking of the anode is complete, it must be heated to about 1100 degrees C. To improve the understanding of the anode baking process and to improve its efficiency, a menu-driven heat, mass and fluid flow simulation tool, called NABSIM (Noranda Anode Baking SIMulation), was developed and calibrated in 1993 and 1994. It has been used since then to evaluate and screen firing practices, and to determine which firing procedure will produce the optimum heat-up rate, final temperature, and soak time, without allowing unburned tar to escape. NABSIM is used as a furnace simulation tool on a daily basis by Noranda plant process engineers and much effort is expended in improving its utility by creating new versions, and the addition of new modules. In the immediate future, efforts will be directed towards optimizing the anode baking process to improve temperature uniformity from pit to pit. 3 refs., 4 figs.

  18. Molten carbonate fuel cell components: Lab scale electrochemical characterization with three-electrode cell; Caratterizzazione elettrochimica di componenti funzionali per MCFC mediante una cella a tre elettrodi in scala di laboratorio

    Energy Technology Data Exchange (ETDEWEB)

    Giorgi, L.; Simonetti, E.; Ciancia, A.; Pozio, A.

    1992-12-31

    This paper describes lab scale experiments conducted on a molten carbonate fuel cell (MCFC) with the aim of obtaining the electrical and electrochemical characteristics of the cell`s principle components. Suitable measurement and data analysis methods were developed to allow the identification of the cathode as the critical MCFC element and establish the cell`s operating regime from the point of view of overvoltage. An investigation was made of the influence, on obtainable power, of the method used to deliver current. Verification of the cell with a galvanostat allowed the maximization of electric power. The electrical resistance of the electrolyte was electronically compensated and the power-current curves were analyzed. Cyclic loading tests made it possible to study the time dependent stability of the MCFC and evidence anodic and cathodic potential variations which significantly affect stability. Electrochemical impedance spectroscopy was used to study reaction orders and electro-reduction mechanisms within the O/sub 2/-CO/sub 2/ cathodic mixture and to verify the performance of the electrodes in thin film electrolyte conditions.

  19. Enhanced Electrochemical Performance of Electrospun Ag/Hollow Glassy Carbon Nanofibers as Free-standing Li-ion Battery Anode

    International Nuclear Information System (INIS)

    Shilpa; Sharma, Ashutosh

    2015-01-01

    Silver with a high theoretical capacity for lithium storage is an attractive alloy based anode for Li-ion batteries, but large volume changes associated with AgLi x alloy formation leads to electrode cracking, pulverization and rapid capacity fading. A buffer matrix, like the electrospun hollow carbon nanofibers, can reduce this problem to a great extent. Herein, we demonstrate the facile synthesis of a free-standing, binder free Ag-C hybrid electrode through co-axial electrospinning, where well dispersed Ag nanoparticles are embedded in hollow carbon nanofibers. Using this approach, the long cycle life of carbon is complemented with the high lithium storage capacity of Ag, resulting in a high performance anode. The Ag-C composite electrode delivers a capacity of 739 mAh g −1 (>conventional graphite anodes) at 50 mA g −1 , with ∼85% capacity retention after 100 cycles. In addition, the Ag-C composite nanofibers are highly porous and exhibit a large accessible surface area (∼726.9 m 2 g −1 ) with an average pore diameter of ∼6.07 nm. The encapsulation of Ag in the hollow interiors not only provides additional lithium storage sites but also enhances the electronic conductivity, which combined with the reduced lithium diffusion path lengths in the nanofibers result in faster charge-discharge kinetics and hence a high rate performance

  20. Persistent cyclestability of carbon coated Zn–Sn metal oxide/carbon microspheres as highly reversible anode material for lithium-ion batteries

    International Nuclear Information System (INIS)

    Fang, Guoqing; Kaneko, Shingo; Liu, Weiwei; Xia, Bingbo; Sun, Hongdan; Zhang, Ruixue; Zheng, Junwei; Li, Decheng

    2013-01-01

    Development of high-capacity anode materials equipped with strong cyclestability is a great challenge for use as practical electrode for high-performance lithium-ion rechargeable battery. In this study, we synthesized a carbon coated Zn–Sn metal nanocomposite oxide and carbon spheres (ZTO@C/CSs) via a simple glucose hydrothermal reaction and subsequent carbonization approach. The carbon coated ZTO/carbon microspheres composite maintained a reversible capacity of 680 mAh g −1 after 345 cycles at a current density of 100 mA g −1 , and furthermore the cell based on the composite exhibited an excellent rate capability of 470 mAh g −1 even when the cell was cycled at 2000 mA g –1 . The thick carbon layer formed on the ZTO nanoparticles and carbon spheres effectively buffered the volumetric change of the particles, which thus prolonged the cycling performance of the electrodes

  1. Carbon-shell-constrained silicon cluster derived from Al-Si alloy as long-cycling life lithium ion batteries anode

    Science.gov (United States)

    Su, Junming; Zhang, Congcong; Chen, Xiang; Liu, Siyang; Huang, Tao; Yu, Aishui

    2018-03-01

    Although silicon is the most promising anode material for Li-ion batteries, large volume expansion during lithiation and delithiation is the main obstacle limiting the commercial application of silicon anodes. There are two ways to alleviate volume expansion and prevent further pulverization of a Si anode: fabrication of a rational nanostructure possessing void spaces and uniform distribution of the conducting sites, without a good balance effect in mitigating the limiting factors and enhancing battery performance. In this paper, we propose a novel nanostructure - a carbon-shell-constrained Si cluster (Si/C shell) with both adequate void space and good distribution of electrical contact sites to guarantee homogeneous lithiation in the initial cycle. Benefiting from the ability to maintain electrical conductivity of the outer carbon shell, even after cluster fragmentation, the Si/C shell synthesized from low-cost commercial Al-Si alloy spheres can deliver 0.03% capacity loss from 100th to 1000th cycles at a current density of 1 A g-1. The Si/C shell sample with the dual functional structure mentioned above can also maintain its own nanostructure during cycling and deliver excellent rate performance. It is a concise and scalable strategy which can simplify the preparation of other alloy anode materials for Li-ion batteries.

  2. Vertical single- and double-walled carbon nanotubes grown from modified porous anodic alumina templates

    International Nuclear Information System (INIS)

    Maschmann, Matthew R; Franklin, Aaron D; Amama, Placidus B; Zakharov, Dmitri N; Stach, Eric A; Sands, Timothy D; Fisher, Timothy S

    2006-01-01

    Vertical single-walled and double-walled carbon nanotube (SWNT and DWNT) arrays have been grown using a catalyst embedded within the pore walls of a porous anodic alumina (PAA) template. The initial film structure consisted of a SiO x adhesion layer, a Ti layer, a bottom Al layer, a Fe layer, and a top Al layer deposited on a Si wafer. The Al and Fe layers were subsequently anodized to create a vertically oriented pore structure through the film stack. CNTs were synthesized from the catalyst layer by plasma-enhanced chemical vapour deposition (PECVD). The resulting structure is expected to form the basis for development of vertically oriented CNT-based electronics and sensors

  3. Size Effect of Ordered Mesoporous Carbon Nanospheres for Anodes in Li-Ion Battery

    Directory of Open Access Journals (Sweden)

    Pei-Yi Chang

    2015-12-01

    Full Text Available The present work demonstrates the application of various sizes of ordered mesoporous carbon nanospheres (OMCS with diameters of 46–130 nm as an active anode material for Li-ion batteries (LIB. The physical and chemical properties of OMCS have been evaluated by performing scanning electron microscopy (SEM, transmission electron microscopy (TEM, N2 adsorption-desorption analysis; small-angle scattering system (SAXS and X-ray diffraction (XRD. The electrochemical analysis of using various sizes of OMCS as anode materials showed high capacity and rate capability with the specific capacity up to 560 mA·h·g−1 at 0.1 C after 85 cycles. In terms of performance at high current rate compared to other amorphous carbonaceous materials; a stable and extremely high specific capacity of 240 mA·h·g−1 at 5 C after 15 cycles was achieved. Such excellent performance is mainly attributed to the suitable particle size distribution of OMCS and intimate contact between OMCS and conductive additives; which can be supported from the TEM images. Results obtained from this study clearly indicate the excellence of size distribution of highly integrated mesoporous structure of carbon nanospheres for LIB application.

  4. High-capacity nanocarbon anodes for lithium-ion batteries

    International Nuclear Information System (INIS)

    Zhang, Haitao; Sun, Xianzhong; Zhang, Xiong; Lin, He; Wang, Kai; Ma, Yanwei

    2015-01-01

    Highlights: • The nanocarbon anodes in lithium-ion batteries deliver a high capacity of ∼1100 mA h g −1 . • The nanocarbon anodes exhibit excellent cyclic stability. • A novel structure of carbon materials, hollow carbon nanoboxes, has potential application in lithium-ion batteries. - Abstract: High energy and power density of secondary cells like lithium-ion batteries become much more important in today’s society. However, lithium-ion battery anodes based on graphite material have theoretical capacity of 372 mA h g −1 and low charging-discharging rate. Here, we report that nanocarbons including mesoporous graphene (MPG), carbon tubular nanostructures (CTN), and hollow carbon nanoboxes (HCB) are good candidate for lithium-ion battery anodes. The nanocarbon anodes have high capacity of ∼1100, ∼600, and ∼500 mA h g −1 at 0.1 A g −1 for MPG, CTN, and HCB, respectively. The capacity of 181, 141, and 139 mA h g −1 at 4 A g −1 for MPG, CTN, and HCB anodes is retained. Besides, nanocarbon anodes show high cycling stability during 1000 cycles, indicating formation of a passivating layer—solid electrolyte interphase, which support long-term cycling. Nanocarbons, constructed with graphene layers which fulfill lithiation/delithiation process, high ratio of graphite edge structure, and high surface area which facilitates capacitive behavior, deliver high capacity and improved rate-capability

  5. Nitrogen-modified carbon nanostructures derived from metal-organic frameworks as high performance anodes for Li-ion batteries

    International Nuclear Information System (INIS)

    Shen, Cai; Zhao, Chongchong; Xin, Fengxia; Cao, Can; Han, Wei-Qiang

    2015-01-01

    Here, we report preparation of nitrogen-modified nanostructure carbons through carbonization of Cu-based metal organic nanofibers at 700 °C under argon gas atmosphere. After removal of copper through chemical treatment with acids, pure N-modified nanostructure carbon with a nitrogen content of 8.62 wt% is obtained. When use as anodes for lithium-ion battery, the nanostructure carbon electrode has a discharge capacity of 853.1 mAh g −1 measured at a current of 500 mA g −1 after 800 cycles.

  6. Electrochemical formation of AlN in molten LiCl-KCl-Li{sub 3}N systems

    Energy Technology Data Exchange (ETDEWEB)

    Goto, Takuya [Department of Fundamental Energy Science, Graduate School of Energy Science, Kyoto University, Sakyo, Kyoto 606-8501 (Japan)]. E-mail: goto@energy.kyoto-u.ac.jp; Iwaki, Takayuki [Department of Fundamental Energy Science, Graduate School of Energy Science, Kyoto University, Sakyo, Kyoto 606-8501 (Japan); Ito, Yasuhiko [Department of Fundamental Energy Science, Graduate School of Energy Science, Kyoto University, Sakyo, Kyoto 606-8501 (Japan)

    2005-01-30

    Electrochemical formation of aluminum nitride was investigated in molten LiCl-KCl-Li{sub 3}N systems at 723 K. When Al was anodically polarized at 1.0 V (versus Li{sup +}/Li), oxidation of nitride ions proceeded to form adsorbed nitrogen atoms, which reacted with the surface to form AlN film. The obtained nitrided film had a thickness of sub-micron order. The obtained nitrided layer consisted of two regions; the outer layer involving AlN and aluminum oxynitride and the inner layer involving metallic Al and AlN. When Al electrode was anodically polarized at 2.0 V, anodic dissolution of Al electrode occurred to give aluminum ions, which reacted with nitride ions in the melt to produce AlN particles (1-5 {mu}m of diameter) of wurtzite structure.

  7. Controlled deposition and utilization of carbon on Ni-YSZ anodes of SOFCs operating on dry methane

    International Nuclear Information System (INIS)

    Jiao, Yong; Zhang, Liqin; An, Wenting; Zhou, Wei; Sha, Yujing; Shao, Zongping; Bai, Jianping; Li, Si-Dian

    2016-01-01

    Solid oxide fuel cells (SOFCs) are promising power-generation systems to utilize methane or methane-based fuels with a high energy efficiency and low environmental impact. A successive multi-stage process is performed to explore the operation of cells using dry methane or the deposited carbon from methane decomposition as fuel. Stable operation can be maintained by optimizing the fuel supply and current density parameters. An electrochemical impedance analysis suggests that the partial oxidization of Ni can occur at anodes when the carbon fuel is consumed. The stability of cells operated on pure methane is investigated in three operating modes. The cell can run in a comparatively stable state with continuous power output in an intermittent methane supply mode, where the deposition and utilization of carbon is controlled by balancing the fuel supply and consumption. The increase in the polarization resistance of the cell might originate from the small amount of NiO and residual carbon at the anode, which can be removed via an oxidation-and-reduction maintenance process. Based on the above strategy, this work provides an alternative operating mode to improve the stability of direct methane SOFCs and demonstrates the feasibility of its application. - Highlights: • A new strategy to control the deposition and utilization of carbon was developed. • A stable fuel cell operation was obtained with an intermittent fuel supply mode. • Polarization resistance increased due to small amount of NiO and residual carbon.

  8. Performance evaluation and parametric optimum design of a molten carbonate fuel cell-thermophotovoltaic cell hybrid system

    International Nuclear Information System (INIS)

    Yang, Zhimin; Liao, Tianjun; Zhou, Yinghui; Lin, Guoxing; Chen, Jincan

    2016-01-01

    Highlights: • A molten carbonate fuel cell-thermophotovoltaic cell hybrid system is established. • The performance characteristics of the hybrid system are systematically evaluated. • The optimal regions of the power output density and efficiency are determined. • The values of key parameters at the maximum power output density are calculated. • The proposed system is proved to have advantages over other hybrid systems. - Abstract: A new model of the hybrid system composed of a molten carbonate fuel cell (MCFC) and a thermophotovoltaic cell (TPVC) is proposed to recovery the waste heat produced by the MCFC. Expressions for the power output and the efficiency of the hybrid system are analytically derived. The performance characteristics of the hybrid system are evaluated. It is found that when the current density of the MCFC, voltage output of the TPVC, electrode area ratio of the MCFC to the TPVC, and energy gap of the material in the photovoltaic cell are optimally chosen, the maximum power output density of the hybrid system is obviously larger than that of the single MCFC. Moreover, the improved percentages of the maximum power output density of the proposed model relative to that of the single MCFC are calculated for differently operating temperatures of the MCFC and are compared with those of some MCFC-based hybrid systems reported in the literature, and consequently, the advantages of the MCFC-TPVC hybrid system are revealed.

  9. An experimental study of aluminium electrowinning using a nickel-based hydrogen diffusion anode

    International Nuclear Information System (INIS)

    Namboothiri, Sankar; Taylor, Mark P.; Chen, John J.J.; Hyland, Margaret M.; Cooksey, Mark A.

    2011-01-01

    Research highlights: → Measurable depolarisation of the anode potential and formation of water vapour. → Metallic aluminium was found on the spent cathode. → HF emissions can be minimised by conducting the electrolysis at 750 o C. → The nickel based anode surface corroded during electrolysis. → Its application is constrained by the material limitation of the porous anode. - Abstract: Laboratory scale electrolysis experiments were conducted to investigate the electrowinning of aluminium using hydrogen diffusion anodes. A potassium-based electrolyte (KF-AlF 3 -Al 2 O 3 ), porous nickel alloy anode and molybdenum disk cathode were used in experiments at 750 o C. Hydrogen gas was supplied to the anode/electrolyte interface through the porous anode. Experiments were conducted in potentiostatic, galvanostatic and galvanodynamic modes. There was a measurable depolarisation of the anode potential and also anode reaction of hydrogen and oxygen ions in the bath to form water vapour was confirmed by the water vapour condensate found at the electrolysis exit gas pipe. Metallic aluminium was found on the spent cathode. The experiments conducted in the galvanodynamic mode suggested that the rate limiter for hydrogen oxidation was the availability of surface hydrogen at the anode/electrolyte interface. The anode surface corroded during electrolysis and impurities were found both in the molten bath and on the cathode.

  10. Effect of inlet fuel type on the degradation of Ni/YSZ anode of solid oxide fuel cell by carbon deposition

    Directory of Open Access Journals (Sweden)

    Suttichai Assabumrungrat

    2006-11-01

    Full Text Available According to the high operating temperature of Solid Oxide Fuel Cell (SOFC (700-1100ºC, it is known that some hydrocarbon fuels can be directly used as inlet fuel instead of hydrogen by feeding straight to the anode. This operation is called a direct internal reforming SOFC (DIR-SOFC. However, the major difficulty of this operation is the possible degradation of anode by the carbon deposition, as the carbon species are easily formed. In the present work, the effect of inlet fuel (i.e. H2, synthesis gas (H2+CO, CH4, CH4+H2O, CH3OH+H2O, and C2H5OH+H2O on the degradation of nickel cermet (Ni/YSZ, which is the most common anode material of SOFC, was studied.It was found from the work that hydrogen and synthesis gas (CO+H2 are proper to be used as direct inlet fuels for DIR-SOFC with Ni/YSZ anode, since the carbon formation on Ni/YSZ occurred in the small quantity. The mixture of methane and steam (CH4+H2O can also be used as the inlet feed, but the H2O/CH4 ratio plays an important role. In contrast, pure methane (CH4, methanol with steam (CH3OH+H2O and ethanol with steam (C2H5OH+H2O are not suitable for using as direct inlet fuel for DIR-SOFC with Ni/YSZ anode even the higher H2O/CH3OH and H2O/C2H5OH ratios were applied.

  11. Uranium dioxide electrolysis

    Science.gov (United States)

    Willit, James L [Batavia, IL; Ackerman, John P [Prescott, AZ; Williamson, Mark A [Naperville, IL

    2009-12-29

    This is a single stage process for treating spent nuclear fuel from light water reactors. The spent nuclear fuel, uranium oxide, UO.sub.2, is added to a solution of UCl.sub.4 dissolved in molten LiCl. A carbon anode and a metallic cathode is positioned in the molten salt bath. A power source is connected to the electrodes and a voltage greater than or equal to 1.3 volts is applied to the bath. At the anode, the carbon is oxidized to form carbon dioxide and uranium chloride. At the cathode, uranium is electroplated. The uranium chloride at the cathode reacts with more uranium oxide to continue the reaction. The process may also be used with other transuranic oxides and rare earth metal oxides.

  12. Electrical and Mechanical Performance of Carbon Fiber-Reinforced Polymer Used as the Impressed Current Anode Material

    Directory of Open Access Journals (Sweden)

    Ji-Hua Zhu

    2014-07-01

    Full Text Available An investigation was performed by using carbon fiber-reinforced polymer (CFRP as the anode material in the impressed current cathodic protection (ICCP system of steel reinforced concrete structures. The service life and performance of CFRP were investigated in simulated ICCP systems with various configurations. Constant current densities were maintained during the tests. No significant degradation in electrical and mechanical properties was found for CFRP subjected to anodic polarization with the selected applied current densities. The service life of the CFRP-based ICCP system was discussed based on the practical reinforced concrete structure layout.

  13. Anodic polarization behavior and film breakdown potential of pure copper in the simulated geological environment containing carbonate

    International Nuclear Information System (INIS)

    Kawasaki, Manabu; Taniguchi, Naoki; Naito, Morimasa

    2009-01-01

    In order to clarify the influence of environmental factors on the corrosion behavior of copper overpacks in oxidizing environment, potentiodynamic and potentiostatic anodic polarization tests were performed in carbonate aqueous solutions at 80degC. As the results, the passivation was promoted and film breakdown was suppressed in higher carbonate concentrations, in lower chloride ion concentrations, and in higher pH conditions. The sulfate ion tended to promote the film breakdown of copper. The effects of the composition of the test solutions on the anodic polarization curve of copper in bentonite/sand mixture were quite smaller than those in simple aqueous solution. By comparison with previous data for lower temperature condition, it was clarified that passivation of copper was promoted in higher temperature condition, but breakdown potential, Eb was independent of temperature. The Eb, was expressed as a function of the ratio of aggressive ion and inhibiting ion such as [Cl - ]/[HCO 3 - ] and [SO 4 2- ]/[HCO 3 - ], and it was confirmed that the Eb was lowered with increasing the ratio. When the ratio exceeds a certain value, the Eb was no longer able to be determined since the anodic polarization curve becomes active dissolution type. The lower limit of Eb in passive type region was estimated to be about -200 mV vs. SCE. The results of potentiostatic tests showed that pitting corrosion or non-uniform corrosion was observed at the potentials over Eb or second current peak potentials in anodic polarization curve. (author)

  14. Automotive assessment of carbon-silicon composite anodes and methods of fabrication

    Science.gov (United States)

    Karulkar, Mohan; Blaser, Rachel; Kudla, Bob

    2015-01-01

    To assess the potential of carbon silicon composite anodes for automotive applications, C-Si anodes were fabricated and certain improvements employed. The use of a PVDF buffer layer is demonstrated for the first time with a C-Si composite material. The buffer layer increases adhesion by 89%, and increases capacity by 50-80%. Also, a limited capacity range is employed to improve cycle life by up to 200%, and enable currents as high as 2 mA cm-1. The combined use of a buffer layer and limited capacity range has not been reported before. A model is also presented for comparing C-Si performance with real-world automotive targets from USABC, including energy density, power density, specific energy, and specific power. The analysis reveals a capacity penalty that arises from pairing C-Si with a traditional cathode (NCA), and which prevents the cell from meeting all targets. Scenarios are presented in which a higher-capacity cathode (250 mAh g-1) allows all targets to be hypothetically met.

  15. Carboxyl functionalized carbon fibers with preserved tensile strength and electrochemical performance used as anodes of structural lithium-ion batteries

    International Nuclear Information System (INIS)

    Feng, Mengjie; Wang, Shubin; Yu, Yalin; Feng, Qihang; Yang, Jiping; Zhang, Boming

    2017-01-01

    Highlights: • Carboxyl functionalized CF is acquired by simple chemical oxidation method. • These CF have preserved the tensile strength, better electrochemical properties. • The presence of H_3PO_4 prevented the turbostratic carbon from over-oxidization. • There CF can be used as anodes of multifunctional structural battery. • The preservation and improvement is result from the hindered over-oxidization. - Abstract: Carboxyl functionalized carbon fibers with preserved tensile strength and electrochemical properties were acquired through a simple chemical oxidation method, and the proposed underlying mechanism was verified. The surface of carboxyl functionalizing carbon fibers is necessary in acquiring functional groups on the surface of carbon fibers to further improve the thermal, electrical or mechanical properties of the fibers. Functionalization should preserve the tensile strength and electrochemical properties of carbon fibers, because the anodes of structural batteries need to have high strength and electrochemical properties. Functionalized with mixed H_2SO_4/HNO_3 considerably reduced the tensile strength of carbon fibers. By contrast, the appearance of H_3PO_4 preserved the tensile strength of functionalized carbon fibers, reduced the dispersion level of tensile strength values, and effectively increased the concentration of functional acid groups on the surface of carbon fibers. The presence of phosphoric acid hindered the over-oxidation of turbostratic carbon, and consequently preserved the tensile strength of carbon fibers. The increased proportion of turbostratic carbon on the surface of carbon fibers concurrently enhanced the electrochemical properties of carbon fibers.

  16. Effects of doped copper on electrochemical performance of the raw carbon nanotubes anode

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zhanhong; Simard, Benoit [SIMS, National Research Council, 100 Sussex Dr., Ottawa, ON (Canada); Li, Zaifeng [ICPET, National Research Council, 1200 Montreal Road, Ottawa, ON (Canada); Wu, Haoqing [Department of Chemistry, Fudan University, Shanghai 200433 (China)

    2003-07-01

    The raw carbon nanotubes pre-doped with copper are used as anode materials for lithium ion batteries. Constant current discharge and charge tests using the raw carbon nanotubes pre-doped with copper as Li{sup +} storage compounds show lower specific capacities than that of the acid-oxidized carbon nanotubes. The acids play an important role; H{sub 2}SO{sub 4} and HNO{sub 3} can easily permeate through the graphene sheets, then they will make the defects or pores in the graphene sheets, and this reaction can make the expansion of the graphite. Meanwhile, Cu{sup 2+} will diffuse into the pores and onto the outer surfaces of the carbon nanotubes. Cu{sup 2+} can be easily turned into Cu at high temperature in the presence of the carbon nanomaterial. So parts of the pores and the surfaces of the carbon nanotubes will be filled with the Cu atom. Once the space positions of the nanotubes were occupied, lithium cannot intercalate into the pores and onto the outer surface of the carbon nanotubes, thus the doped carbon nanotubes will have a low specific capacity.

  17. Nanoporous Mo2C functionalized 3D carbon architecture anode for boosting flavins mediated interfacial bioelectrocatalysis in microbial fuel cells

    Science.gov (United States)

    Zou, Long; Lu, Zhisong; Huang, Yunhong; Long, Zhong-er; Qiao, Yan

    2017-08-01

    An efficient microbial electrocatalysis in microbial fuel cells (MFCs) needs both high loading of microbes (biocatalysts) and robust interfacial electron transfer from microbes to electrode. Herein a nanoporous molybdenum carbide (Mo2C) functionalized carbon felt electrode with rich 3D hierarchical porous architecture is applied as MFC anode to achieve superior electrocatalytic performance. The nanoporous Mo2C functionalized anode exhibits strikingly improved microbial electrocatalysis in MFCs with 5-fold higher power density and long-term stability of electricity production. The great enhancement is attributed to the introduction of rough Mo2C nanostructural interface into macroporous carbon architecture for promoting microbial growth with great excretion of endogenous electron shuttles (flavins) and rich available nanopores for enlarging electrochemically active surface area. Importantly, the nanoporous Mo2C functionalized anode is revealed for the first time to have unique electrocatalytic activity towards redox reaction of flavins with more negative redox potential, indicating a more favourable thermodynamic driving force for anodic electron transfer. This work not only provides a promising electrode for high performance MFCs but also brings up a new insight into the effect of nanostructured materials on interfacial bioelectrocatalysis.

  18. The Optimized Tin Dioxide-Carbon Nanocomposites as High-performance Anode for Lithium ion Battery with a long cycle life

    International Nuclear Information System (INIS)

    Wan, Yuanxin; Sha, Ye; Deng, Weijia; Zhu, Qing; Chen, Zhen; Wang, Xiaoliang; Chen, Wei; Xue, Gi; Zhou, Dongshan

    2015-01-01

    Tin dioxide (SnO 2 ) is one of the most promising anode materials for the next generation Li-ion batteries due to its high capacity. To solve the problems caused by the large volume change (over 300%) and the aggregation of the tin particles formed during cycling, nano SnO 2 /C composites are proved to be ideal anode materials for high performance Li-ion batteries. However, it is still a challenge to disperse ultrasmall (<6 nm) SnO 2 nanoparticles with uniform size in carbon matrix. Here, we report a facile hydrothermal way to get such optimized nano SnO 2 /C composite, in which well dispersed ultrasmall SnO 2 nanocrystals (3∼5 nm) are embedded in a conductive carbon matrix. With this anode, we demonstrate a high stable capacity of 928 mAh g −1 based on the total mass of the composite at a current density of 500 mA g −1 . At high current density of 2 A g −1 , this composite anode shows a capacity of 853 mAh g −1 in the first charge, in such high current density, we can even get a capacity retention of more than 91% (779 mAh g −1 ) after 1000 cycles

  19. High cyclability of carbon-coated TiO2 nanoparticles as anode for sodium-ion batteries

    International Nuclear Information System (INIS)

    Ge, Yeqian; Jiang, Han; Zhu, Jiadeng; Lu, Yao; Chen, Chen; Hu, Yi; Qiu, Yiping; Zhang, Xiangwu

    2015-01-01

    Highlights: • Titanium oxide nanopaticles were modified by carbon coating from pyrolyzing of PVP. • Carbon coating gave rise to excellent cycling ability of TiO 2 for sodium-ion batteries. • The reversible capacity of carbon-coated TiO 2 reached 242.3 mAh g −1 at 30 mA g −1 . • Good rate performance of carbon-coated TiO 2 was presented up to 800 mA g −1 . - Abstract: Owing to the merits of good chemical stability, elemental abundance and nontoxicity, titanium dioxide (TiO 2 ) has drawn increasing attraction for use as anode material in sodium-ion batteries. Nanostructured TiO 2 was able to achieve high energy density. However, nanosized TiO 2 is typically electrochemical instable, which leads to poor cycling performance. In order to improve the cycling stability, carbon from thermolysis of poly(vinyl pyrrolidone) was coated onto TiO 2 nanoparticles. Electronic conductivity and electrochemical stability were enhanced by coating carbon onto TiO 2 nanoparticles. The resultant carbon-coated TiO 2 nanoparticles exhibited high reversible capacity (242.3 mAh g −1 ), high coulombic efficiency (97.8%), and good capacity retention (87.0%) at 30 mA g −1 over 100 cycles. By comparison, untreated TiO 2 nanoparticles showed comparable reversible capacity (237.3 mAh g −1 ) and coulombic efficiency (96.2%), but poor capacity retention (53.2%) under the same condition. The rate performance of carbon-coated TiO 2 nanoparticles was also displayed as high as 127.6 mAh g −1 at a current density of 800 mA g −1 . The improved cycling performance and rate capability were mostly attributed to protective carbon layer helping stablize solid electrolyte interface formation of TiO 2 nanoparticles and improving the electronic conductivity. Therefore, it is demonstrated that carbon-coated TiO 2 nanoparticles are promising anode candidate for sodium-ion batteries

  20. A high performance lithium ion capacitor achieved by the integration of a Sn-C anode and a biomass-derived microporous activated carbon cathode.

    Science.gov (United States)

    Sun, Fei; Gao, Jihui; Zhu, Yuwen; Pi, Xinxin; Wang, Lijie; Liu, Xin; Qin, Yukun

    2017-02-03

    Hybridizing battery and capacitor materials to construct lithium ion capacitors (LICs) has been regarded as a promising avenue to bridge the gap between high-energy lithium ion batteries and high-power supercapacitors. One of the key difficulties in developing advanced LICs is the imbalance in the power capability and charge storage capacity between anode and cathode. Herein, we design a new LIC system by integrating a rationally designed Sn-C anode with a biomass-derived activated carbon cathode. The Sn-C nanocomposite obtained by a facile confined growth strategy possesses multiple structural merits including well-confined Sn nanoparticles, homogeneous distribution and interconnected carbon framework with ultra-high N doping level, synergically enabling the fabricated anode with high Li storage capacity and excellent rate capability. A new type of biomass-derived activated carbon featuring both high surface area and high carbon purity is also prepared to achieve high capacity for cathode. The assembled LIC (Sn-C//PAC) device delivers high energy densities of 195.7 Wh kg -1 and 84.6 Wh kg -1 at power densities of 731.25 W kg -1 and 24375 W kg -1 , respectively. This work offers a new strategy for designing high-performance hybrid system by tailoring the nanostructures of Li insertion anode and ion adsorption cathode.

  1. Light-Weight Free-Standing Carbon Nanotube-Silicon Films for Anodes of Lithium Ion Batteries

    KAUST Repository

    Cui, Li-Feng

    2010-07-27

    Silicon is an attractive alloy-type anode material because of its highest known capacity (4200 mAh/g). However, lithium insertion into and extraction from silicon are accompanied by a huge volume change, up to 300%, which induces a strong strain on silicon and causes pulverization and rapid capacity fading due to the loss of the electrical contact between part of silicon and current collector. Si nanostructures such as nanowires, which are chemically and electrically bonded to the current collector, can overcome the pulverization problem, however, the heavy metal current collectors in these systems are larger in weight than Si active material. Herein we report a novel anode structure free of heavy metal current collectors by integrating a flexible, conductive carbon nanotube (CNT) network into a Si anode. The composite film is free-standing and has a structure similar to the steel bar reinforced concrete, where the infiltrated CNT network functions as both mechanical support and electrical conductor and Si as a high capacity anode material for Li-ion battery. Such free-standing film has a low sheet resistance of ∼30 Ohm/sq. It shows a high specific charge storage capacity (∼2000 mAh/g) and a good cycling life, superior to pure sputtered-on silicon films with similar thicknesses. Scanning electron micrographs show that Si is still connected by the CNT network even when small breaking or cracks appear in the film after cycling. The film can also "ripple up" to release the strain of a large volume change during lithium intercalation. The conductive composite film can function as both anode active material and current collector. It offers ∼10 times improvement in specific capacity compared with widely used graphite/copper anode sheets. © 2010 American Chemical Society.

  2. Self-doped carbon architectures with heteroatoms containing nitrogen, oxygen and sulfur as high-performance anodes for lithium- and sodium-ion batteries

    International Nuclear Information System (INIS)

    Lu, Mingjie; Yu, Wenhua; Shi, Jing; Liu, Wei; Chen, Shougang; Wang, Xin; Wang, Huanlei

    2017-01-01

    Highlights: •Self-doped carbon architectures with nitrogen, oxygen, and sulfur are derived from Carrageen. •The obtained carbon materials exhibit excellent electrochemical property. •The strategy provides a one-step synthesis route to design advanced anodes for batteries. -- Abstract: Nitrogen, oxygen and sulfur tridoped porous carbons have been successfully synthesized from natural biomass algae-Carrageen by using a simultaneous carbonization and activation procedure. The doped carbons with sponge-like interconnected architecture, partially ordered graphitic structure, and abundant heteroatom doping perform outstanding features for electrochemical energy storage. When tested as lithium-ion battery anodes, a high reversible capacity of 839 mAh g −1 can be obtained at the current density of 0.1 A g −1 after 100 cycles, while a high capacity of 228 mAh g −1 can be maintained at 10 A g −1 . Tested against sodium, a high specific capacity of 227 can be delivered at 0.1 A g −1 after 100 cycles, while a high capacity of 109 mAh g −1 can be achieved at 10 A g −1 . These results turn out that the doped carbons would be potential anode materials for lithium- and sodium-ion batteries, which can be achieved by a one-step and large-scale synthesis route. Our observation indicates that heteroatom doping (especially sulfur) can significantly promote ion storage and reduce irreversible ion trapping to some extent. This work gives a general route for designing carbon nanostructures with heteroatom doping for efficient energy storage.

  3. Numerical Investigation on the Impact of Anode Change on Heat Transfer and Fluid Flow in Aluminum Smelting Cells

    Science.gov (United States)

    Wang, Qiang; Gosselin, Louis; Fafard, Mario; Peng, Jianping; Li, Baokuan

    2016-04-01

    In order to understand the impact of anode change on heat transfer and magnetohydrodynamic flow in aluminum smelting cells, a transient three-dimensional (3D) coupled mathematical model has been developed. The solutions of the mass, momentum, and energy conservation equations were simultaneously implemented by the finite volume method with full coupling of the Joule heating and Lorentz force through solving the electrical potential equation. The volume of fluid approach was employed to describe the two-phase flow. The phase change of molten electrolyte (bath) as well as molten aluminum (metal) was modeled by an enthalpy-based technique, where the mushy zone is treated as a porous medium with a porosity equal to the liquid fraction. The effect of the new anode temperature on recovery time was also analyzed. A reasonable agreement between the test data and simulated results is obtained. The results indicate that the temperature of the bath under cold anodes first decreases reaching the minimal value and rises under the effect of increasing Joule heating, and finally returns to steady state. The colder bath decays the velocity, and the around ledge becomes thicker. The lowest temperature of the bath below new anodes increases from 1118 K to 1143 K (845 °C to 870 °C) with the new anode temperature ranging from 298 K to 498 K (25°C to 225°C), and the recovery time reduces from 22.5 to 20 hours.

  4. Scalable synthesis of interconnected porous silicon/carbon composites by the Rochow reaction as high-performance anodes of lithium ion batteries.

    Science.gov (United States)

    Zhang, Zailei; Wang, Yanhong; Ren, Wenfeng; Tan, Qiangqiang; Chen, Yunfa; Li, Hong; Zhong, Ziyi; Su, Fabing

    2014-05-12

    Despite the promising application of porous Si-based anodes in future Li ion batteries, the large-scale synthesis of these materials is still a great challenge. A scalable synthesis of porous Si materials is presented by the Rochow reaction, which is commonly used to produce organosilane monomers for synthesizing organosilane products in chemical industry. Commercial Si microparticles reacted with gas CH3 Cl over various Cu-based catalyst particles to substantially create macropores within the unreacted Si accompanying with carbon deposition to generate porous Si/C composites. Taking advantage of the interconnected porous structure and conductive carbon-coated layer after simple post treatment, these composites as anodes exhibit high reversible capacity and long cycle life. It is expected that by integrating the organosilane synthesis process and controlling reaction conditions, the manufacture of porous Si-based anodes on an industrial scale is highly possible. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. High-Performance Li-Ion Capacitor Based on an Activated Carbon Cathode and Well-Dispersed Ultrafine TiO2 Nanoparticles Embedded in Mesoporous Carbon Nanofibers Anode.

    Science.gov (United States)

    Yang, Cheng; Lan, Jin-Le; Liu, Wen-Xiao; Liu, Yuan; Yu, Yun-Hua; Yang, Xiao-Ping

    2017-06-07

    A novel Li-ion capacitor based on an activated carbon cathode and a well-dispersed ultrafine TiO 2 nanoparticles embedded in mesoporous carbon nanofibers (TiO 2 @PCNFs) anode was reported. A series of TiO 2 @PCNFs anode materials were prepared via a scalable electrospinning method followed by carbonization and a postetching method. The size of TiO 2 nanoparticles and the mesoporous structure of the TiO 2 @PCNFs were tuned by varying amounts of tetraethyl orthosilicate (TEOS) to increase the energy density and power density of the LIC significantly. Such a subtle designed LIC displayed a high energy density of 67.4 Wh kg -1 at a power density of 75 W kg -1 . Meanwhile, even when the power density was increased to 5 kW kg -1 , the energy density can still maintain 27.5 Wh kg -1 . Moreover, the LIC displayed a high capacitance retention of 80.5% after 10000 cycles at 10 A g -1 . The outstanding electrochemical performance can be contributed to the synergistic effect of the well-dispersed ultrafine TiO 2 nanoparticles, the abundant mesoporous structure, and the conductive carbon networks.

  6. Carbon monoxide tolerant anodes for proton exchange membrane (PEM) fuel cells. 1. Catalyst development approach

    Energy Technology Data Exchange (ETDEWEB)

    Holleck, G L; Pasquariello, D M; Clauson, S L

    1998-07-01

    PEM fuel cells are highly attractive for distributed power and cogeneration systems. They are efficient and function virtually without noise or pollution. To be competitive PEM fuel cells must operate on fuel mixtures obtained by reforming of widely available natural gas or liquid hydrocarbons. Reformed fuel gas mixtures invariably contain CO, a strong poison for Pt. Therefore CO tolerant anode catalysts are essential for wide spread PEMFC introduction. It is the objective to develop effective CO tolerant fuel cell catalysts based on multi-component platinum-transition metal alloys. Towards this goal the authors have developed a novel approach for the synthesis and performance evaluation of multifunctional ternary alloy fuel cell catalysts. The alloys are prepared as well-defined thin films on standard TFE-bonded carbon substrates via a dc magnetron sputtering technique. The anodes are laminated to Nafion membranes and the electrochemical performance is measured in a representative fuel cell configuration with H{sub 2} and H{sub 2}/CO gas mixtures. The multi-target sputtering technique permits one to reproducibly synthesize true alloy films of controlled composition. The deposit morphology and electrode structure are determined by the standardized TFE bonded carbon substrate. The thin catalyst layer is concentrated at the electrode ionomer interface where it can be fully utilized in a representative fuel cell configuration. Thus, a true comparative fuel cell catalyst evaluation is possible. The effectiveness of this approach will be demonstrated with Pt, Pt-Ru and Pt-Ru-X catalyzed anodes.

  7. Ceramic carbon electrode-based anodes for use in the Cu-Cl thermochemical cycle

    Energy Technology Data Exchange (ETDEWEB)

    Ranganathan, Santhanam; Easton, E. Bradley [Faculty of Science, University of Ontario Institute of Technology, 2000 Simcoe Street North, Oshawa, Ontario (Canada)

    2010-05-15

    We have investigated CCE materials prepared using 3-aminopropyl trimethoxysilane. Electrochemical experiments were performed to characterize their suitability as anode electrode materials for use in the electrochemical step of the Cu-Cl thermochemical cycle. CCE-based electrodes vastly outperform a bare carbon electrode. Optimization of the organosilicate loading revealed maximum electrode performance was achieved with 36 wt% and was explained in terms of the optimal balance of active area and anion transport properties. (author)

  8. Electrophoretic deposition of multi-walled carbon nanotubes on porous anodic aluminum oxide using ionic liquid as a dispersing agent

    Science.gov (United States)

    Hekmat, F.; Sohrabi, B.; Rahmanifar, M. S.; Jalali, A.

    2015-06-01

    Multi-wall carbon nanotubes (MW-CNTs) have been arranged in nanochannels of anodic aluminum oxide template (AAO) by electrophoretic deposition (EPD) to make a vertically-aligned carbon nanotube (VA-CNT) based electrode. Well ordered AAO templates were prepared by a two-step anodizing process by applying a constant voltage of 45 V in oxalic acid solution. The stabilized CNTs in a water-soluble room temperature ionic liquid (1-methyl-3-octadecylimidazolium bromide), were deposited in the pores of AAO templates which were conductive by deposition of Ni nanoparticles in the bottom of pores. In order to obtain ideal results, different EPD parameters, such as concentration of MWCNTs and ionic liquid on stability of MWCNT suspensions, deposition time and voltage which are applied in EPD process and also optimal conditions for anodizing of template were investigated. The capacitive performance of prepared electrodes was analyzed by measuring the specific capacitance from cyclic voltammograms and the charge-discharge curves. A maximum value of 50 Fg-1 at the scan rate of 20 mV s-1was achieved for the specific capacitance.

  9. Biomass carbon micro/nano-structures derived from ramie fibers and corncobs as anode materials for lithium-ion and sodium-ion batteries

    International Nuclear Information System (INIS)

    Jiang, Qiang; Zhang, Zhenghao; Yin, Shengyu; Guo, Zaiping; Wang, Shiquan; Feng, Chuanqi

    2016-01-01

    Highlights: • Ramie fibers and corncobs are used as precursors to prepare the biomass carbons. • The ramie fiber carbon (RFC) took on morphology of 3D micro-rods. • The corncob carbon (CC) possessed a 2D nanosheets structure. • Both RFC and CC exhibited outstanding electrochemical performances in LIBs and SIBs systems. - Abstract: Three-dimensional (3D) rod-like carbon micro-structures derived from natural ramie fibers and two-dimensional (2D) carbon nanosheets derived from corncobs have been fabricated by heat treatment at 700 °C under argon atomsphere. The structure and morphology of the as-obtained ramie fiber carbon (RFC) and corncob carbon (CC) were characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) technique. The electrochemical performances of the biomass carbon-based anode in lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) were investigated. When tested as anode material for lithium ion batteries, both the RFC microrods and CC nanosheets exhibited high capacity, excellent rate capability, and stable cyclability. The specific capacity were still as high as 489 and 606 mAhg −1 after 180 cycles when cycled at room temperature in a 3.0–0.01 V potential (vs. Li/Li + ) window at current density of 100 mAg −1 , respectively, which are much higher than that of graphite (375 mAhg −1 ) under the same current density. Although the anodes in sodium ion batteries showed poorer specific capability than that in lithium-ion batteries, they still achieve a reversible sodium intercalation capacity of 122 and 139 mAhg −1 with similar cycling stability. The feature of stable cycling performance makes the biomass carbon derived from natural ramie fibers and corncobs to be promising candidates as electrodes in rechargeable sodium-ion batteries and lithium-ion batteries.

  10. Biomass carbon micro/nano-structures derived from ramie fibers and corncobs as anode materials for lithium-ion and sodium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Qiang; Zhang, Zhenghao [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry-of-Education Key Laboratory for Synthesis and Applications of Organic Functional Molecules, Hubei University, Wuhan 430062 (China); Yin, Shengyu [College of Environmental and Biological Engineering, Wuhan Technology and Business University, Wuhan 430065 (China); Guo, Zaiping [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry-of-Education Key Laboratory for Synthesis and Applications of Organic Functional Molecules, Hubei University, Wuhan 430062 (China); Institute for Superconducting & Electronic Materials, University of Wollongong, NSW 2522 (Australia); Wang, Shiquan [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry-of-Education Key Laboratory for Synthesis and Applications of Organic Functional Molecules, Hubei University, Wuhan 430062 (China); Feng, Chuanqi, E-mail: cfeng@hubu.edu.cn [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry-of-Education Key Laboratory for Synthesis and Applications of Organic Functional Molecules, Hubei University, Wuhan 430062 (China)

    2016-08-30

    Highlights: • Ramie fibers and corncobs are used as precursors to prepare the biomass carbons. • The ramie fiber carbon (RFC) took on morphology of 3D micro-rods. • The corncob carbon (CC) possessed a 2D nanosheets structure. • Both RFC and CC exhibited outstanding electrochemical performances in LIBs and SIBs systems. - Abstract: Three-dimensional (3D) rod-like carbon micro-structures derived from natural ramie fibers and two-dimensional (2D) carbon nanosheets derived from corncobs have been fabricated by heat treatment at 700 °C under argon atomsphere. The structure and morphology of the as-obtained ramie fiber carbon (RFC) and corncob carbon (CC) were characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) technique. The electrochemical performances of the biomass carbon-based anode in lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) were investigated. When tested as anode material for lithium ion batteries, both the RFC microrods and CC nanosheets exhibited high capacity, excellent rate capability, and stable cyclability. The specific capacity were still as high as 489 and 606 mAhg{sup −1} after 180 cycles when cycled at room temperature in a 3.0–0.01 V potential (vs. Li/Li{sup +}) window at current density of 100 mAg{sup −1}, respectively, which are much higher than that of graphite (375 mAhg{sup −1}) under the same current density. Although the anodes in sodium ion batteries showed poorer specific capability than that in lithium-ion batteries, they still achieve a reversible sodium intercalation capacity of 122 and 139 mAhg{sup −1} with similar cycling stability. The feature of stable cycling performance makes the biomass carbon derived from natural ramie fibers and corncobs to be promising candidates as electrodes in rechargeable sodium-ion batteries and lithium-ion batteries.

  11. Thermal Properties of LiCl-KCl Molten Salt for Nuclear Waste Separation

    Energy Technology Data Exchange (ETDEWEB)

    Sridharan, Kumar [Univ. of Wisconsin, Madison, WI (United States); Allen, Todd [Univ. of Wisconsin, Madison, WI (United States); Anderson, Mark [Univ. of Wisconsin, Madison, WI (United States); Simpson, Mike [Idaho National Lab., (United States)

    2012-11-30

    This project addresses both practical and fundamental scientific issues of direct relevance to operational challenges of the molten LiCl-KCl salt pyrochemical process, while providing avenues for improvements in the process. In order to understand the effects of the continually changing composition of the molten salt bath during the process, the project team will systematically vary the concentrations of rare earth surrogate elements, lanthanum, cerium, praseodymium, and neodymium, which will be added to the molten LiCl-KCl salt. They will also perform a limited number of focused experiments by the dissolution of depleted uranium. All experiments will be performed at 500 deg C. The project consists of the following tasks. Researchers will measure density of the molten salts using an instrument specifically designed for this purpose, and will determine the melting points with a differential scanning calorimeter. Knowledge of these properties is essential for salt mass accounting and taking the necessary steps to prevent melt freezing. The team will use cyclic voltammetry studies to determine redox potentials of the rare earth cations, as well as their diffusion coefficients and activities in the molten LiCl-KCl salt. In addition, the team will perform anodic stripping voltammetry to determine the concentration of the rare earth elements and their solubilities, and to develop the scientific basis for an on-line diagnostic system for in situ monitoring of the cation species concentration (rare earths in this case). Solubility and activity of the cation species are critically important for the prediction of the salt's useful lifetime and disposal.

  12. Thermal Properties of LiCl-KCl Molten Salt for Nuclear Waste Separation

    International Nuclear Information System (INIS)

    Sridharan, Kumar; Allen, Todd; Anderson, Mark; Simpson, Mike

    2012-01-01

    This project addresses both practical and fundamental scientific issues of direct relevance to operational challenges of the molten LiCl-KCl salt pyrochemical process, while providing avenues for improvements in the process. In order to understand the effects of the continually changing composition of the molten salt bath during the process, the project team will systematically vary the concentrations of rare earth surrogate elements, lanthanum, cerium, praseodymium, and neodymium, which will be added to the molten LiCl-KCl salt. They will also perform a limited number of focused experiments by the dissolution of depleted uranium. All experiments will be performed at 500 deg C. The project consists of the following tasks. Researchers will measure density of the molten salts using an instrument specifically designed for this purpose, and will determine the melting points with a differential scanning calorimeter. Knowledge of these properties is essential for salt mass accounting and taking the necessary steps to prevent melt freezing. The team will use cyclic voltammetry studies to determine redox potentials of the rare earth cations, as well as their diffusion coefficients and activities in the molten LiCl-KCl salt. In addition, the team will perform anodic stripping voltammetry to determine the concentration of the rare earth elements and their solubilities, and to develop the scientific basis for an on-line diagnostic system for in situ monitoring of the cation species concentration (rare earths in this case). Solubility and activity of the cation species are critically important for the prediction of the salt's useful lifetime and disposal

  13. Carboxyl functionalized carbon fibers with preserved tensile strength and electrochemical performance used as anodes of structural lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Mengjie [School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Wang, Shubin, E-mail: shubinwang@buaa.edu.cn [School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Yu, Yalin; Feng, Qihang; Yang, Jiping; Zhang, Boming [School of Materials Science and Engineering, Beihang University, Beijing 100191 (China)

    2017-01-15

    Highlights: • Carboxyl functionalized CF is acquired by simple chemical oxidation method. • These CF have preserved the tensile strength, better electrochemical properties. • The presence of H{sub 3}PO{sub 4} prevented the turbostratic carbon from over-oxidization. • There CF can be used as anodes of multifunctional structural battery. • The preservation and improvement is result from the hindered over-oxidization. - Abstract: Carboxyl functionalized carbon fibers with preserved tensile strength and electrochemical properties were acquired through a simple chemical oxidation method, and the proposed underlying mechanism was verified. The surface of carboxyl functionalizing carbon fibers is necessary in acquiring functional groups on the surface of carbon fibers to further improve the thermal, electrical or mechanical properties of the fibers. Functionalization should preserve the tensile strength and electrochemical properties of carbon fibers, because the anodes of structural batteries need to have high strength and electrochemical properties. Functionalized with mixed H{sub 2}SO{sub 4}/HNO{sub 3} considerably reduced the tensile strength of carbon fibers. By contrast, the appearance of H{sub 3}PO{sub 4} preserved the tensile strength of functionalized carbon fibers, reduced the dispersion level of tensile strength values, and effectively increased the concentration of functional acid groups on the surface of carbon fibers. The presence of phosphoric acid hindered the over-oxidation of turbostratic carbon, and consequently preserved the tensile strength of carbon fibers. The increased proportion of turbostratic carbon on the surface of carbon fibers concurrently enhanced the electrochemical properties of carbon fibers.

  14. Red Phosphorus-Embedded Cross-Link-Structural Carbon Films as Flexible Anodes for Highly Reversible Li-Ion Storage

    Energy Technology Data Exchange (ETDEWEB)

    Ruan, Jiafeng [School of Materials; Yuan, Tao [School of Materials; Pang, Yuepeng [School of Materials; Xu, Xinbo [School of Materials; Yang, Junhe [School of Materials; Hu, Wenbin; Zhong, Cheng; Ma, Zi-Feng [Shanghai Electrochemical Energy Devices Research Center,; Bi, Xuanxuan [Chemical; Zheng, Shiyou [School of Materials

    2017-10-06

    Red phosphorus (P) is considered to be one of the most attractive anodic materials for lithium-ion batteries (LIBs) due to its high theoretical capacity of 2596 mAh g–1. However, intrinsic characteristics such as the poor electronic conductivity and large volume expansion at lithiation impede the development of red P. Here, we design a new strategy to embed red P particles into a cross-link-structural carbon film (P–C film), in order to improve the electronic conductivity and accommodate the volume expansion. The red P/carbon film is synthesized via vapor phase polymerization (VPP) followed by the pyrolysis process, working as a flexible binder-free anode for LIBs. High cycle stability and good rate capability are achieved by the P–C film anode. With 21% P content in the film, it displays a capacity of 903 mAh g–1 after 640 cycles at a current density of 100 mA g–1 and a capacity of 460 mAh g–1 after 1000 cycles at 2.0 A g–1. Additionally, the Coulombic efficiency reaches almost 100% for each cycle. The superior properties of the P–C films together with their facile fabrication make this material attractive for further flexible and high energy density LIB applications.

  15. Effect of anodic surface treatment on PAN-based carbon fiber and its relationship to the fracture toughness of the carbon fiber-reinforced polymer composites

    DEFF Research Database (Denmark)

    Sarraf, Hamid; Skarpova, Ludmila

    2008-01-01

    The effect of anodic surface treatment on the polyacrylonitrile (PAN)-based carbon fibers surface properties and the mechanical behavior of the resulting carbon fiber-polymer composites has been studied in terms of the contact angle measurements of fibers and the fracture toughness of composites...... in the fiber surface nature and the mechanical interfacial properties between the carbon fiber and epoxy resin matrix of the resulting composites, i.e., the fracture toughness. We suggest that good wetting plays an important role in improving the degree of adhesion at interfaces between fibers and matrices...

  16. Ceramic carbon electrode-based anodes for use in the copper-chlorine thermochemical cycle

    International Nuclear Information System (INIS)

    Ranganathan, S.; Easton, E.B.

    2009-01-01

    Sol-gel chemistry is becoming more popular for the synthesis of electrode materials. For example, the sol-gel reaction can be performed in the presence of a carbon black to form a ceramic carbon electrode (CCE). The resultant CCE structure contains electronically conductive carbon particle pathways that are bound together via the ceramic binder, which can also promote ion transport. Furthermore, the CCE structure has a high active surface area and is chemical and thermally robust. We have investigated CCE materials prepared using 3-aminopropyl trimethoxysilane. Electrochemical experiments (cyclic voltammetry, electrochemical impedance spectroscopy) were performed to characterize their suitability as anode electrode materials for use in the electrochemical step of the Cu-Cl thermochemical cycle. Our initial results have shown that CCE-based electrodes vastly outperform a bare carbon electrode, and thus are highly promising and cost-effective electrode material. Subsequent experiments involved the manipulation of the relative ratio of organosilane carbon precursors to gauge its impact on electrode properties and performance. An overview of the materials characterization and electrochemical measurements will be presented. (author)

  17. Ceramic carbon electrode-based anodes for use in the copper-chlorine thermochemical cycle

    Energy Technology Data Exchange (ETDEWEB)

    Ranganathan, S.; Easton, E.B. [Faculty of Science, Univ. of Ontario Inst. of Technology, Oshawa, Ontario (Canada)], E-mail: ranga@uoit.ca, Brad.Easton@uoit.ca

    2009-07-01

    Sol-gel chemistry is becoming more popular for the synthesis of electrode materials. For example, the sol-gel reaction can be performed in the presence of a carbon black to form a ceramic carbon electrode (CCE). The resultant CCE structure contains electronically conductive carbon particle pathways that are bound together via the ceramic binder, which can also promote ion transport. Furthermore, the CCE structure has a high active surface area and is chemical and thermally robust. We have investigated CCE materials prepared using 3-aminopropyl trimethoxysilane. Electrochemical experiments (cyclic voltammetry, electrochemical impedance spectroscopy) were performed to characterize their suitability as anode electrode materials for use in the electrochemical step of the Cu-Cl thermochemical cycle. Our initial results have shown that CCE-based electrodes vastly outperform a bare carbon electrode, and thus are highly promising and cost-effective electrode material. Subsequent experiments involved the manipulation of the relative ratio of organosilane carbon precursors to gauge its impact on electrode properties and performance. An overview of the materials characterization and electrochemical measurements will be presented. (author)

  18. Mesoporous carbon anchored with SnS2 nanosheets as an advanced anode for lithium-ion batteries

    International Nuclear Information System (INIS)

    Li, Jianping; Wu, Ping; Lou, Feijian; Zhang, Peng; Tang, Yawen; Zhou, Yiming; Lu, Tianhong

    2013-01-01

    Highlights: •SnS 2 nanosheets densely and uniformly anchored on 3D mesoporous carbon matrix. •Unique structural characteristics of both 2D nanosheet and 3D porous carbon matrix. •Markedly enhanced lithium storage capability by virtue of its structure superiority. -- Abstract: This paper reports a novel type of nanohybrid, mesoporous carbon anchored with SnS 2 nanosheets (MC-SnS 2 NSs), which integrates the structural characteristics of both two-dimensional (2D) nanosheet and 3D porous carbon matrix. When evaluated as an anode for lithium-ion batteries, the MC-SnS 2 NSs exhibits significantly enhanced cycling stability and rate capability by virtue of its unique structural superiority

  19. Copper anode corrosion affects power generation in microbial fuel cells

    KAUST Repository

    Zhu, Xiuping

    2013-07-16

    Non-corrosive, carbon-based materials are usually used as anodes in microbial fuel cells (MFCs). In some cases, however, metals have been used that can corrode (e.g. copper) or that are corrosion resistant (e.g. stainless steel, SS). Corrosion could increase current through galvanic (abiotic) current production or by increasing exposed surface area, or decrease current due to generation of toxic products from corrosion. In order to directly examine the effects of using corrodible metal anodes, MFCs with Cu were compared with reactors using SS and carbon cloth anodes. MFCs with Cu anodes initially showed high current generation similar to abiotic controls, but subsequently they produced little power (2 mW m-2). Higher power was produced with microbes using SS (12 mW m-2) or carbon cloth (880 mW m-2) anodes, with no power generated by abiotic controls. These results demonstrate that copper is an unsuitable anode material, due to corrosion and likely copper toxicity to microorganisms. © 2013 Society of Chemical Industry.

  20. Copper anode corrosion affects power generation in microbial fuel cells

    KAUST Repository

    Zhu, Xiuping; Logan, Bruce E.

    2013-01-01

    Non-corrosive, carbon-based materials are usually used as anodes in microbial fuel cells (MFCs). In some cases, however, metals have been used that can corrode (e.g. copper) or that are corrosion resistant (e.g. stainless steel, SS). Corrosion could increase current through galvanic (abiotic) current production or by increasing exposed surface area, or decrease current due to generation of toxic products from corrosion. In order to directly examine the effects of using corrodible metal anodes, MFCs with Cu were compared with reactors using SS and carbon cloth anodes. MFCs with Cu anodes initially showed high current generation similar to abiotic controls, but subsequently they produced little power (2 mW m-2). Higher power was produced with microbes using SS (12 mW m-2) or carbon cloth (880 mW m-2) anodes, with no power generated by abiotic controls. These results demonstrate that copper is an unsuitable anode material, due to corrosion and likely copper toxicity to microorganisms. © 2013 Society of Chemical Industry.

  1. Carboxyl functionalization of carbon fibers via aryl diazonium reaction in molten urea to enhance interfacial shear strength

    Science.gov (United States)

    Wang, Yuwei; Meng, Linghui; Fan, Liquan; Wu, Guangshun; Ma, Lichun; Zhao, Min; Huang, Yudong

    2016-01-01

    Using molten urea as the solvent, carbon fibers were functionalized with carboxylic acid groups via aryl diazonium reaction in 15 min to improve their interfacial bonding with epoxy resin. The surface functionalization was quantified by X-ray photoelectron spectroscopy, which showed that the relative surface coverage of carboxylic acid groups increased from an initial percentage of 3.17-10.41%. Mechanical property test results indicated that the aryl diazonium reaction in this paper could improve the interfacial shear strength by 66%. Meanwhile, the technique did not adopt any pre-oxidation step to produce functional groups prior to grafting and was shown to maintain the tensile strength of the fibers. This methodology provided a rapid, facile and economically viable route to produce covalently functionalized carbon fibers in large quantities with an eco-friendly method.

  2. In situ preparation of Fe3O4 in a carbon hybrid of graphene nanoscrolls and carbon nanotubes as high performance anode material for lithium-ion batteries

    Science.gov (United States)

    Liu, Yuewen; Hassan Siddique, Ahmad; Huang, Heran; Fang, Qile; Deng, Wei; Zhou, Xufeng; Lu, Huanming; Liu, Zhaoping

    2017-11-01

    A new conductive carbon hybrid combining both reduced graphene nanoscrolls and carbon nanotubes (rGNSs-CNTs) is prepared, and used to host Fe3O4 nanoparticles through an in situ synthesis method. As an anode material for LIBs, the obtained Fe3O4@rGNSs-CNTs shows good electrochemical performance. At a current density of 0.1 A g-1, the anode material shows a high reversible capacity of 1232.9 mAh g-1 after 100 cycles. Even at a current density of 1 A g-1, it still achieves a high reversible capacity of 812.3 mAh g-1 after 200 cycles. Comparing with bare Fe3O4 and Fe3O4/rGO composite anode materials without nanoscroll structure, Fe3O4@rGNSs-CNTs shows much better rate capability with a reversible capacity of 605.0 and 500.0 mAh g-1 at 3 and 5 A g-1, respectively. The excellent electrochemical performance of the Fe3O4@rGNSs-CNTs anode material can be ascribed to the hybrid structure of rGNSs-CNTs, and their strong interaction with Fe3O4 nanoparticles, which on one hand provides more pathways for lithium ions and electrons, on the other hand effectively relieves the volume change of Fe3O4 during the charge-discharge process.

  3. Carbon fuel cells with carbon corrosion suppression

    Science.gov (United States)

    Cooper, John F [Oakland, CA

    2012-04-10

    An electrochemical cell apparatus that can operate as either a fuel cell or a battery includes a cathode compartment, an anode compartment operatively connected to the cathode compartment, and a carbon fuel cell section connected to the anode compartment and the cathode compartment. An effusion plate is operatively positioned adjacent the anode compartment or the cathode compartment. The effusion plate allows passage of carbon dioxide. Carbon dioxide exhaust channels are operatively positioned in the electrochemical cell to direct the carbon dioxide from the electrochemical cell.

  4. Effect of wrinkles on electrochemical performance of multiwalled carbon nanotubes as anode material for Li ion battery

    International Nuclear Information System (INIS)

    Sahoo, Madhumita; Ramaprabhu, S.

    2015-01-01

    Highlights: • Wrinkly surfaced gC is employed as anode material for Li ion battery. • Temperature controlled protrusions were uniformly distributed over the nanotubes. • gC shows superior performance of 373 mAh g −1 at 100 mA g −1 after 150 cycle. • Synergistic effect of defects and conductivity gives higher Li storage over MWNTs. - Abstract: A 1-D monohybrid of multiwalled carbon nanotubes and graphene sheets, graphene wrapped multiwalled carbon nanotubes (gC) structure, synthesized in a template-free simple chemical vapor deposition technique without any chemical functionalization, was employed as efficient anode material for Li ion battery. Graphene nanosheets affixed to the multiwalled carbon nanotubes (MWNTs) surface by van der Waal's attraction gives a wrinkled surface to the final 1-D gC configuration. The protrusions on the surface of the tube enhances the porosity of the system and also acts as defects, enhancing lithium adsorption sites while the inner MWNT core gives high electrical conductivity, resulting enhanced electrochemical performance of 373 mAh g −1 at 100 mA g −1 current density after 150 cycles.

  5. Hybrid direct carbon fuel cell anode processes investigated using a 3-electrode half-cell setup

    DEFF Research Database (Denmark)

    Deleebeeck, Lisa; Arenillas, A.; Menendez, J.A.

    2015-01-01

    anthracite and bituminous coals, as well as carbon black, were tested, revealing similar open circuit potential and activation energies in mixed 96-4vol% N2-CO2 and 50-50vol% CO-CO2 environments between 700 and 800°C. Bituminous coal showed the highest activity, likely associated to a high O/C ratio...... and hydrogen content. Based on acquired data, a reaction scheme was proposed for processes at the working electrode, including the role of bubble formation in the vicinity of the electrochemically active solid/molten medium interface....

  6. The Role of Cesium Cation in Controlling Interphasial Chemistry on Graphite Anode in Propylene Carbonate-Rich Electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, Hongfa; Mei, Donghai; Yan, Pengfei; Bhattacharya, Priyanka; Burton, Sarah D.; Cresce, Arthur V.; Cao, Ruiguo; Engelhard, Mark H.; Bowden, Mark E.; Zhu, Zihua; Polzin, Bryant; Wang, Chong M.; Xu, Kang; Zhang, Jiguang; Xu, Wu

    2015-09-10

    Propylene carbonate (PC) is seldom used in lithium-ion batteries (LIBs) due to its sustained co-intercalation into graphene structure and the eventual graphite exfoliation, despite potential advantages it brings, such as wider liquid range and lower cost. Here we discover that cesium cation (Cs+), originally used to suppress dendrite growth of Li metal anode, directs the formation of solid electrolyte interphase (SEI) on graphitic anode in PC-rich electrolytes through preferential solvation. Effective suppression of PC-decomposition and graphite-exfoliation was achieved when the ratio of ethylene carbonate (EC)/PC in electrolytes was so adjusted that the reductive decomposition of Cs+-(EC)m (1≤m≤2) complex precedes that of Li+-(PC)n (3≤n≤5). The interphase directed by Cs+ is stable, ultrathin and compact, leading to significant improvements in LIB performances. In a broader context, the accurate tailoring of SEI chemical composition by introducing a new solvation center represents a fundamental breakthrough in manipulating interfacial reactions processes that once were elusive.

  7. Silver-incorporated composites of Fe2O3 carbon nanofibers as anodes for high-performance lithium batteries

    Science.gov (United States)

    Zou, Mingzhong; Li, Jiaxin; Wen, WeiWei; Chen, Luzhuo; Guan, Lunhui; Lai, Heng; Huang, Zhigao

    2014-12-01

    Composites of Ag-incorporated carbon nanofibers (CNFs) confined with Fe2O3 nanoparticles (Ag-Fe2O3/CNFs) have been synthesized through an electrospinning method and evaluated as anodes for lithium batteries (LIBs). The obtained Ag-Fe2O3/CNF anodes show good LIB performance with a capacity of 630 mAh g-1 tested at 800 mA g-1 after 150 cycles with almost no capacity loss and superb rate performance. The obtained properties for Ag-Fe2O3/CNF anodes are much better than Fe2O3/CNF anodes without Ag-incorporating. In addition, the low-temperature LIB performances for Ag-Fe2O3/CNF anodes have been investigated for revealing the enhanced mechanism of Ag-incorporating. The superior electrochemical performances of the Ag-Fe2O3/CNFs are associated with a synergistic effect of the CNF matrix and the highly conducting Ag incorporating. This unique configuration not only facilitates electron conduction especially at a relative temperature, but also maintains the structural integrity of active materials. Meanwhile, the related analysis of the AC impedance spectroscopy and the corresponding hypothesis for DC impedance confirm that such configuration can effectively enhance the charge-transfer efficiency and the lithium diffusion coefficient. Therefore, CNF-supported coupled with Ag incorporating synthesis supplied a promising route to obtain Fe2O3 based anodes with high-performance LIBs especially at low temperature.

  8. Investigation of mechanism of anode plasma formation in ion diode with dielectric anode

    International Nuclear Information System (INIS)

    Pushkarev, A.

    2015-01-01

    The results of investigation of the anode plasma formation in a diode with a passive anode in magnetic insulation mode are presented. The experiments have been conducted using the BIPPAB-450 ion accelerator (350–400 kV, 6–8 kA, 80 ns) with a focusing conical diode with B r external magnetic field (a barrel diode). For analysis of plasma formation at the anode and the distribution of the ions beam energy density, infrared imaging diagnostics (spatial resolution of 1–2 mm) is used. For analysis of the ion beam composition, time-of-flight diagnostics (temporal resolution of 1 ns) were used. Our studies have shown that when the magnetic induction in the A-C gap is much larger than the critical value, the ion beam energy density is close to the one-dimensional Child-Langmuir limit on the entire working surface of the diode. Formation of anode plasma takes place only by the flashover of the dielectric anode surface. In this mode, the ion beam consists primarily of singly ionized carbon ions, and the delay of the start of formation of the anode plasma is 10–15 ns. By reducing the magnetic induction in the A-C gap to a value close to the critical one, the ion beam energy density is 3–6 times higher than that calculated by the one-dimensional Child-Langmuir limit, but the energy density of the ion beam is non-uniform in cross-section. In this mode, the anode plasma formation occurs due to ionization of the anode material with accelerated electrons. In this mode, also, the delay in the start of the formation of the anode plasma is much smaller and the degree of ionization of carbon ions is higher. In all modes occurred effective suppression of the electronic component of the total current, and the diode impedance was 20–30 times higher than the values calculated for the mode without magnetic insulation of the electrons. The divergence of the ion beam was 4.5°–6°

  9. Anodic Voltammetric determination of gemifloxacin using screen-printed carbon electrode

    Directory of Open Access Journals (Sweden)

    Abd-Elgawad Radi

    2013-04-01

    Full Text Available The electrochemical oxidation behavior and voltammetric assay of gemifloxacin were investigated using differential-pulse and cyclic voltammetry on a screen-printed carbon electrode. The effects of pH, scan rates, and concentration of the drug on the anodic peak current were studied. Voltammograms of gemifloxacin in Tris–HCl buffer (pH 7.0 exhibited a well-defined single oxidation peak. A differential-pulse voltammetric procedure for the quantitation of gemifloxacin has been developed and suitably validated with respect to linearity, limits of detection and quantification, accuracy, precision, specificity, and robustness. The calibration was linear from 0.5 to 10.0 μM, and the limits of detection and quantification were 0.15 and 5.0 μM. Recoveries ranging from 96.26% to 103.64% were obtained. The method was successfully applied to the determination of gemifloxacin in pharmaceutical tablets without any pre-treatment. Excipients present in the tablets did not interfere in the assay. Keywords: Screen-printed carbon electrode, Voltammetry, Gemifloxacin, Pharmaceutical analysis

  10. Three-dimensional free-standing carbon nanotubes for a flexible lithium-ion battery anode

    International Nuclear Information System (INIS)

    Kang, Chiwon; Cha, Eunho; Baskaran, Rangasamy; Choi, Wonbong

    2016-01-01

    Flexible lithium-ion batteries (LIBs) have received considerable attention as energy sources for wearable electronics. In recent years, much effort has been devoted to study light-weight, robust, and flexible electrodes. However, high areal and volumetric capacities need to be achieved for practical power and energy densities. In this paper, we report the use of three-dimensional (3D) free-standing carbon nanotubes (CNTs) as a current collector-free anode to demonstrate flexible LIBs with enhanced areal and volumetric capacities. High density CNTs grown on copper (Cu) mesh are transferred to a flexible graphene/polyethylene terephthalate  film and integrated into a flexible LIB. A fully flexible LIB cell integrated with the 3D CNT anode delivers a high areal capacity of 0.25 mAh cm"−"2 at 0.1C and shows fairly consistent open circuit voltage under bending. These findings may provide significant advances in the application of flexible LIB based electronic devices. (paper)

  11. Effect of nitrogen addition on the performance of microbial fuel cell anodes

    KAUST Repository

    Saito, Tomonori

    2011-01-01

    Carbon cloth anodes were modified with 4(N,N-dimethylamino)benzene diazonium tetrafluoroborate to increase nitrogen-containing functional groups at the anode surface in order to test whether the performance of microbial fuel cells (MFCs) could be improved by controllably modifying the anode surface chemistry. Anodes with the lowest extent of functionalization, based on a nitrogen/carbon ratio of 0.7 as measured by XPS, achieved the highest power density of 938mW/m2. This power density was 24% greater than an untreated anode, and similar to that obtained with an ammonia gas treatment previously shown to increase power. Increasing the nitrogen/carbon ratio to 3.8, however, decreased the power density to 707mW/m2. These results demonstrate that a small amount of nitrogen functionalization on the carbon cloth material is sufficient to enhance MFC performance, likely as a result of promoting bacterial adhesion to the surface without adversely affecting microbial viability or electron transfer to the surface. © 2010 Elsevier Ltd.

  12. Deposition of nano-size particles on reticulated vitreous carbon using colloidal precursors : three-dimensional anodes for borohydride fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Choi, J.; Gyenge, E.L. [British Columbia Univ., Vancouver, BC (Canada). Dept. of Chemical and Biological Engineering

    2006-07-01

    In addition to their inherently larger specific surface area, mesoscopic materials also possess a higher density of surface constrained sites, which could serve as active sites in catalysis as well as facilitate the surface diffusion of small molecules and ions relevant to various catalytic steps. This study investigated the organosol method for the deposition of platinum (Pt), iridium (Ir), gold (Au) and nickel (Ni) nano-particles on reticulated vitreous carbon to evaluate the electrocatalytic activity for BH{sub 4} oxidation by both fundamental electrochemical studies and fuel cell experiments. The application of the organosol nanometal preparation technique was based on the quaternary ammonium compound N(C{sub 8}H{sub 17}){sub 4}B(C{sub 2}H{sub 5}){sub 3}H acting as both reductant and colloid stabilizer. A current assisted variant was also studied where the reticulated vitreous carbon substrate served as the cathode operating at superficial current densities between 1.0 and 2.5 mA per cm{sup 2}. The organosol method produced a low catalyst load on reticulated vitreous carbons between 0.01 and 0.12 mg per cm{sup 2}. The electrodes were evaluated for catalytic activity toward the electro-oxidation of BH{sub 4} by cyclic voltammetry, chronopotentiometry and fuel cell experiments. Borohydride fuel cells with liquid electrolyte (2 M NaOH) were assembled using a 3-dimensional anode, a cation exchange membrane and a commercial oxygen cathode. Results showed that the anode catalyst mass activity was higher for the 3-D design compared to the case when a gas diffusion electrode served as the anode. It was concluded that the extended reaction zone of the three-dimensional anode with liquid electrolyte improved the catalyst utilization efficiency by allowing the reduction of the catalyst load. 6 refs., 1 fig.

  13. Bio-electro oxidation of indigo carmine by using microporous activated carbon fiber felt as anode and bioreactor support.

    Science.gov (United States)

    Garcia, Luane Ferreira; Rodrigues Siqueira, Ana Claudia; Lobón, Germán Sanz; Marcuzzo, Jossano Saldanha; Pessela, Benevides Costa; Mendez, Eduardo; Garcia, Telma Alves; de Souza Gil, Eric

    2017-11-01

    The bioremediation and electro-oxidation (EO) processes are included among the most promising cleaning and decontamination mechanisms of water. The efficiency of bioremediation is dictated by the biological actuator for a specific substrate, its suitable immobilization and all involved biochemical concepts. The EO performance is defined by the anode efficiency to perform the complete mineralization of target compounds and is highlighted by the low or null use of reagent. Recently, the combination of both technologies has been proposed. Thus, the development of high efficient, low cost and eco-friendly anodes for sustainable EO, as well as, supporting devices for immobilization of biological systems applied in bioremediation is an open field of research. Therefore, the aim of this work was to promote the bio-electrochemical remediation of indigo carmine dye (widely common in textile industry), using new anode based on a microporous activated carbon fiber felt (ACFF) and ACFF with immobilized Laccase (Lcc) from Pycnoporus sanguineus. The results were discolorations of 62.7% with ACFF anode and 83.60% with ACFF-MANAE-Lcc anode, both for 60 min in tap water. This remediation rates show that this new anode has low cost and efficiency in the degradation of indigo dye and can be applied for other organic pollutant. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Advanced CSiC composites for high-temperature nuclear heat transport with helium, molten salts, and sulphur-iodine thermochemical hydrogen process fluids

    International Nuclear Information System (INIS)

    Peterson, P.F.; Forsberg, Ch.W.; Pickard, P.S.

    2004-01-01

    This paper discusses the use of liquid-silicon-impregnated (LSI) carbon-carbon composites for the development of compact and inexpensive heat exchangers, piping, vessels and pumps capable of operating in the temperature range of 800 to 1 100 deg C with high-pressure helium, molten fluoride salts, and process fluids for sulfur-iodine thermochemical hydrogen production. LSI composites have several potentially attractive features, including ability to maintain nearly full mechanical strength to temperatures approaching 1 400 deg C, inexpensive and commercially available fabrication materials, and the capability for simple forming, machining and joining of carbon-carbon performs, which permits the fabrication of highly complex component geometries. In the near term, these materials may prove to be attractive for use with a molten-salt intermediate loop for the demonstration of hydrogen production with a gas-cooled high temperature reactor. In the longer term, these materials could be attractive for use with the molten-salt cooled advanced high temperature reactor, molten salt reactors, and fusion power plants. (author)

  15. Conductive ceramic composition and method of preparation

    Science.gov (United States)

    Smith, J.L.; Kucera, E.H.

    1991-04-16

    A ceramic anode composition is formed of a multivalent metal oxide or oxygenate such as an alkali metal, transition metal oxygenate. The anode is prepared as a non-stoichiometric crystalline structure by reaction and conditioning in a hydrogen gas cover containing minor proportions of carbon dioxide and water vapor. The structure exhibits a single phase and substantially enhanced electrical conductivity over that of the corresponding stoichiometric structure. Unexpectedly, such oxides and oxygenates are found to be stable in the reducing anode fuel gas of a molten carbonate fuel cell. 4 figures.

  16. Volume reduction of waste contaminated by fission product elements and plutonium using molten salt combustion

    International Nuclear Information System (INIS)

    McKenzie, D.E.; Grantham, L.F.; Paulson, R.B.

    1979-01-01

    In the Molten Salt Combustion Process, transuranic or β-γ organic waste and air are continuously introduced beneath the surface of a sodium carbonate-containing melt at a temperature of about 800 0 C. Complete combustion of the organic material to carbon dioxide and steam occurs without the conversion of nitrogen to nitrogen oxides. The noxious gases formed by combustion of the chloride, sulfur or phosphorus content of the waste instantly react with the melt to form the corresponding sodium compounds. These compounds as well as the ash and radionuclides are retained in the molten salt. The spent salt is either fused cast into an engineered disposal container or processed to recover salt and plutonium. Molten salt combustion reduces the waste to about 2% of its original volume. Many reactor or reprocessing wastes which cannot be incinerated without difficulty are readily combusted in the molten salt. A 50 kg/hr molten salt combustion system is being designed for the Radioactive Waste Management Complex at the Idaho National Engineering Laboratory. Construction of the combustor started during 1977, and combustor startup was scheduled for the spring of 1978

  17. Electrodeposition of niobium and titanium in molten salts

    International Nuclear Information System (INIS)

    Sartori, A.F.; Chagas, H.C.

    1988-01-01

    The electrodeposition of niobium and titanium in molten fluorides from the additions of fluorine niobates and fluorine titanates of potassium is described in laboratory and pilot scale. The temperature influence, the current density and the time deposition over the current efficiency, the deposits structure and the deposits purity are studied. The conditions for niobium coating over copper and carbon steel and for titanium coating over carbon steel are also presented. (C.G.C.) [pt

  18. A New Anode for Lithium-Ion Batteries Based on Single-Walled Carbon Nanotubes and Graphene: Improved Performance through a Binary Network Design.

    Science.gov (United States)

    Ren, Jing; Ren, Rui-Peng; Lv, Yong-Kang

    2018-05-04

    Carbon nanomaterials, especially graphene and carbon nanotubes, are considered to be favorable alternatives to graphite-based anodes in lithium-ion batteries, owing to their high specific surface area, electrical conductivity, and excellent mechanical flexibility. However, the limited number of storage sites for lithium ions within the sp 2 -carbon hexahedrons leads to the low storage capacity. Thus, rational structure design is essential for the preparation of high-performance carbon-based anode materials. Herein, we employed flexible single-walled carbon nanotubes (SWCNTs) with ultrahigh electrical conductivity as a wrapper for 3D graphene foam (GF) by using a facile dip-coating process to form a binary network structure. This structure, which offered high electrical conductivity, enlarged the electrode/electrolyte contact area, shortened the electron-/ion-transport pathways, and allowed for efficient utilization of the active material, which led to improved electrochemical performance. When used as an anode in lithium-ion batteries, the SWCNT-GF electrode delivered a specific capacity of 953 mA h g -1 at a current density of 0.1 A g -1 and a high reversible capacity of 606 mA h g -1 after 1000 cycles, with a capacity retention of 90 % over 1000 cycles at 1 A g -1 and 189 mA h g -1 after 2200 cycles at 5 A g -1 . © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. In Situ High-Level Nitrogen Doping into Carbon Nanospheres and Boosting of Capacitive Charge Storage in Both Anode and Cathode for a High-Energy 4.5 V Full-Carbon Lithium-Ion Capacitor.

    Science.gov (United States)

    Sun, Fei; Liu, Xiaoyan; Wu, Hao Bin; Wang, Lijie; Gao, Jihui; Li, Hexing; Lu, Yunfeng

    2018-05-02

    To circumvent the imbalances of electrochemical kinetics and capacity between Li + storage anodes and capacitive cathodes for lithium-ion capacitors (LICs), we herein demonstrate an efficient solution by boosting the capacitive charge-storage contributions of carbon electrodes to construct a high-performance LIC. Such a strategy is achieved by the in situ and high-level doping of nitrogen atoms into carbon nanospheres (ANCS), which increases the carbon defects and active sites, inducing more rapidly capacitive charge-storage contributions for both Li + storage anodes and PF 6 - storage cathodes. High-level nitrogen-doping-induced capacitive enhancement is successfully evidenced by the construction of a symmetric supercapacitor using commercial organic electrolytes. Coupling a pre-lithiated ANCS anode with a fresh ANCS cathode enables a full-carbon LIC with a high operating voltage of 4.5 V and high energy and power densities thereof. The assembled LIC device delivers high energy densities of 206.7 and 115.4 Wh kg -1 at power densities of 0.225 and 22.5 kW kg -1 , respectively, as well as an unprecedented high-power cycling stability with only 0.0013% capacitance decay per cycle within 10 000 cycles at a high power output of 9 kW kg -1 .

  20. Analysis of carbon fiber brush loading in anodes on startup and performance of microbial fuel cells

    KAUST Repository

    Hutchinson, Adam J.

    2011-11-01

    Flat carbon anodes placed near a cathode in a microbial fuel cell (MFC) are adversely affected by oxygen crossover, but graphite fiber brush anodes placed near the cathode produce high power densities. The impact of the brush size and electrode spacing was examined by varying the distance of the brush end from the cathode and solution conductivity in multiple MFCs. The startup time was increased from 8 ± 1 days with full brushes (all buffer concentrations) to 13 days (50 mM), 14 days (25 mM) and 21 days (8 mM) when 75% of the brush anode was removed. When MFCs were all first acclimated with a full brush, up to 65% of the brush material could be removed without appreciably altering maximum power. Electrochemical impedance spectroscopy (EIS) showed that the main source of internal resistance (IR) was diffusion resistance, which together with solution resistance reached 100 Ω. The IR using EIS compared well with that obtained using the polarization data slope method, indicating no major components of IR were missed. These results show that using full brush anodes avoids adverse effects of oxygen crossover during startup, although brushes are much larger than needed to sustain high power. © 2011 Elsevier B.V.

  1. Analysis of carbon fiber brush loading in anodes on startup and performance of microbial fuel cells

    KAUST Repository

    Hutchinson, Adam J.; Tokash, Justin C.; Logan, Bruce E.

    2011-01-01

    Flat carbon anodes placed near a cathode in a microbial fuel cell (MFC) are adversely affected by oxygen crossover, but graphite fiber brush anodes placed near the cathode produce high power densities. The impact of the brush size and electrode spacing was examined by varying the distance of the brush end from the cathode and solution conductivity in multiple MFCs. The startup time was increased from 8 ± 1 days with full brushes (all buffer concentrations) to 13 days (50 mM), 14 days (25 mM) and 21 days (8 mM) when 75% of the brush anode was removed. When MFCs were all first acclimated with a full brush, up to 65% of the brush material could be removed without appreciably altering maximum power. Electrochemical impedance spectroscopy (EIS) showed that the main source of internal resistance (IR) was diffusion resistance, which together with solution resistance reached 100 Ω. The IR using EIS compared well with that obtained using the polarization data slope method, indicating no major components of IR were missed. These results show that using full brush anodes avoids adverse effects of oxygen crossover during startup, although brushes are much larger than needed to sustain high power. © 2011 Elsevier B.V.

  2. Formation of titanium diboride coatings during the anodic polarization of titanium in a chloride melt with a low boron oxide content

    Science.gov (United States)

    Elshina, L. A.; Malkov, V. B.; Molchanova, N. G.

    2015-02-01

    The corrosion-electrochemical behavior of titanium in a molten eutectic mixture of cesium and sodium chlorides containing up to 1 wt % boron oxide is studied in the temperature range 810-870 K in an argon atmosphere. The potential, the current, and the rate of titanium corrosion are determined. The optimum conditions of forming a dense continuous titanium diboride coating on titanium with high adhesion to the metallic base are found for the anodic activation of titanium in the molten electrolyte under study.

  3. Ethylene carbonate-free fluoroethylene carbonate-based electrolyte works better for freestanding Si-based composite paper anodes for Li-ion batteries

    Science.gov (United States)

    Yao, K.; Zheng, J. P.; Liang, R.

    2018-03-01

    Fluoroethylene carbonate (FEC)-based electrolytes using FEC as the co-solvent (50 wt%) are investigated and compared with the electrolyte using FEC as the additive (10 wt%) for freestanding Si-carbon nanotubes (CNTs) composite paper anodes for Li-ion batteries. The ethylene carbonate (EC)-free FEC-based electrolyte is found to achieve higher specific capacity and better capacity retention in terms of long-term cycling. After 500 cycles, the capacity retention of the cell using diethyl carbonate (DEC)-FEC (1:1 w/w) is increased by 88% and 60% compared to the cells using EC-DEC-FEC (45:45:10 w/w/w) and EC-FEC (1:1 w/w), respectively. Through SEM-EDX and XPS analyses, a possible reaction route of formation of fluorinated semicarbonates and polyolefins from FEC is proposed. The inferior cell performance related to the EC-containing electrolytes is likely due to the formation of more polyolefins, which do not favor Li ion migration.

  4. Performance analysis of irreversible molten carbonate fuel cell – Braysson heat engine with ecological objective approach

    International Nuclear Information System (INIS)

    Açıkkalp, Emin

    2017-01-01

    Highlights: • An irreversible MCFC - Braysson heat engine is considered. • Its performance is investigated with ecological approach. • A new ecological criteria are presented called as modified ecological function. • Result are obtained numerically and discussed. - Abstract: An irreversible hybrid molten carbonate fuel cell-Braysson heat engine is taken into account. Basic thermodynamics parameters including power output, efficiency and exergy destruction rate are considered. In addition ecological function and new criteria, which is based on ecological function, for heat engines called as modified ecological function is suggested. Optimum conditions for mentioned parameters above are determined. Numerical results are obtained and plotted. Finally, results are discussed.

  5. Investigation of different anode materials for aluminium rechargeable batteries

    Science.gov (United States)

    Muñoz-Torrero, David; Leung, Puiki; García-Quismondo, Enrique; Ventosa, Edgar; Anderson, Marc; Palma, Jesús; Marcilla, Rebeca

    2018-01-01

    In order to shed some light into the importance of the anodic reaction in reversible aluminium batteries, we investigate here the electrodeposition of aluminium in an ionic liquid electrolyte (BMImCl-AlCl3) using different substrates. We explore the influence of the type of anodic material (aluminium, stainless steel and carbon) and its 3D geometry on the reversibility of the anodic reaction by cyclic voltammetry (CV) and galvanostatic charge-discharge. The shape of the CVs confirms that electrodeposition of aluminium was feasible in the three materials but the highest peak currents and smallest peak separation in the CV of the aluminium anode suggested that this material was the most promising. Interestingly, carbon-based substrates appeared as an interesting alternative due to the high peak currents in CV, moderate overpotentials and dual role as anode and cathode. 3D substrates such as fiber-based carbon paper and aluminium mesh showed significantly smaller overpotentials and higher efficiencies for Al reaction suggesting that the use of 3D substrates in full batteries might result in enhanced power. This is corroborated by polarization testing of full Al-batteries.

  6. Hierarchical silicon nanowires-carbon textiles matrix as a binder-free anode for high-performance advanced lithium-ion batteries

    Science.gov (United States)

    Liu, Bin; Wang, Xianfu; Chen, Haitian; Wang, Zhuoran; Chen, Di; Cheng, Yi-Bing; Zhou, Chongwu; Shen, Guozhen

    2013-01-01

    Toward the increasing demands of portable energy storage and electric vehicle applications, the widely used graphite anodes with significant drawbacks become more and more unsuitable. Herein, we report a novel scaffold of hierarchical silicon nanowires-carbon textiles anodes fabricated via a facile method. Further, complete lithium-ion batteries based on Si and commercial LiCoO2 materials were assembled to investigate their corresponding across-the-aboard performances, demonstrating their enhanced specific capacity (2950 mAh g−1 at 0.2 C), good repeatability/rate capability (even >900 mAh g−1 at high rate of 5 C), long cycling life, and excellent stability in various external conditions (curvature, temperature, and humidity). Above results light the way to principally replacing graphite anodes with silicon-based electrodes which was confirmed to have better comprehensive performances. PMID:23572030

  7. Effect of Nitrogen Post-Doping on a Commercial Platinum-Ruthenium/Carbon Anode Catalyst

    Science.gov (United States)

    2014-02-15

    published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at...3 mg cm2 for each anode. During MEA assembly into the fuel cell hardware, 5 cm2 carbon paper with a microporous layer (SGL GDL 25BC) was placed on...7 (2005) 373. [4] A.K. Shukla, J. Electrochem. Soc. 141 (1994) 1517. [5] Z. Lei, et al., Microporous Mesoporous Mater. 119 (2009) 30e38. [6] X. Li, S

  8. An in situ method of creating metal oxide–carbon composites and their application as anode materials for lithium-ion batteries

    KAUST Repository

    Yang, Zichao; Shen, Jingguo; Archer, Lynden A.

    2011-01-01

    Transition metal oxides are actively investigated as anode materials for lithium-ion batteries (LIBs), and their nanocomposites with carbon frequently show better performance in galvanostatic cycling studies, compared to the pristine metal oxide

  9. Rational Design of Si@SiO2/C Composites Using Sustainable Cellulose as a Carbon Resource for Anodes in Lithium-Ion Batteries.

    Science.gov (United States)

    Shen, Dazhi; Huang, Chaofan; Gan, Lihui; Liu, Jian; Gong, Zhengliang; Long, Minnan

    2018-03-07

    In this work, we propose a novel and facile route for the rational design of Si@SiO 2 /C anode materials by using sustainable and environment-friendly cellulose as a carbon resource. To simultaneously obtain a SiO 2 layer and a carbon scaffold, a specially designed homogeneous cellulose solution and commercial Si nanopowder are used as the starting materials, and the cellulose/Si composite is directly assembled by an in situ regenerating method. Subsequently, Si@SiO 2 /C composite is obtained after carbonization. As expected, Si@SiO 2 is homogeneously encapsulated in the cellulose-derived carbon network. The obtained Si@SiO 2 /C composite shows a high reversible capacity of 1071 mA h g -1 at a current density of 420 mA g -1 and 70% capacity retention after 200 cycles. This novel, sustainable, and effective design is a promising approach to obtain high-performance and cost-effective composite anodes for practical applications.

  10. Vertically grown multiwalled carbon nanotube anode and nickel silicide integrated high performance microsized (1.25 μl) microbial fuel cell

    KAUST Repository

    Mink, Justine E.

    2012-02-08

    Microbial fuel cells (MFCs) are an environmentally friendly method for water purification and self-sustained electricity generation using microorganisms. Microsized MFCs can also be a useful power source for lab-on-a-chip and similar integrated devices. We fabricated a 1.25 μL microsized MFC containing an anode of vertically aligned, forest type multiwalled carbon nanotubes (MWCNTs) with a nickel silicide (NiSi) contact area that produced 197 mA/m 2 of current density and 392 mW/m 3 of power density. The MWCNTs increased the anode surface-to-volume ratio, which improved the ability of the microorganisms to couple and transfer electrons to the anode. The use of nickel silicide also helped to boost the output current by providing a low resistance contact area to more efficiently shuttle electrons from the anode out of the device. © 2012 American Chemical Society.

  11. Integration of a molten carbonate fuel cell with a direct exhaust absorption chiller

    Science.gov (United States)

    Margalef, Pere; Samuelsen, Scott

    A high market value exists for an integrated high-temperature fuel cell-absorption chiller product throughout the world. While high-temperature, molten carbonate fuel cells are being commercially deployed with combined heat and power (CHP) and absorption chillers are being commercially deployed with heat engines, the energy efficiency and environmental attributes of an integrated high-temperature fuel cell-absorption chiller product are singularly attractive for the emerging distributed generation (DG) combined cooling, heating, and power (CCHP) market. This study addresses the potential of cooling production by recovering and porting the thermal energy from the exhaust gas of a high-temperature fuel cell (HTFC) to a thermally activated absorption chiller. To assess the practical opportunity of serving an early DG-CCHP market, a commercially available direct fired double-effect absorption chiller is selected that closely matches the exhaust flow and temperature of a commercially available HTFC. Both components are individually modeled, and the models are then coupled to evaluate the potential of a DG-CCHP system. Simulation results show that a commercial molten carbonate fuel cell generating 300 kW of electricity can be effectively coupled with a commercial 40 refrigeration ton (RT) absorption chiller. While the match between the two "off the shelf" units is close and the simulation results are encouraging, the match is not ideal. In particular, the fuel cell exhaust gas temperature is higher than the inlet temperature specified for the chiller and the exhaust flow rate is not sufficient to achieve the potential heat recovery within the chiller heat exchanger. To address these challenges, the study evaluates two strategies: (1) blending the fuel cell exhaust gas with ambient air, and (2) mixing the fuel cell exhaust gases with a fraction of the chiller exhaust gas. Both cases are shown to be viable and result in a temperature drop and flow rate increase of the

  12. Integration of a molten carbonate fuel cell with a direct exhaust absorption chiller

    Energy Technology Data Exchange (ETDEWEB)

    Margalef, Pere; Samuelsen, Scott [National Fuel Cell Research Center (NFCRC), University of California, Irvine, CA 92697-3550 (United States)

    2010-09-01

    A high market value exists for an integrated high-temperature fuel cell-absorption chiller product throughout the world. While high-temperature, molten carbonate fuel cells are being commercially deployed with combined heat and power (CHP) and absorption chillers are being commercially deployed with heat engines, the energy efficiency and environmental attributes of an integrated high-temperature fuel cell-absorption chiller product are singularly attractive for the emerging distributed generation (DG) combined cooling, heating, and power (CCHP) market. This study addresses the potential of cooling production by recovering and porting the thermal energy from the exhaust gas of a high-temperature fuel cell (HTFC) to a thermally activated absorption chiller. To assess the practical opportunity of serving an early DG-CCHP market, a commercially available direct fired double-effect absorption chiller is selected that closely matches the exhaust flow and temperature of a commercially available HTFC. Both components are individually modeled, and the models are then coupled to evaluate the potential of a DG-CCHP system. Simulation results show that a commercial molten carbonate fuel cell generating 300 kW of electricity can be effectively coupled with a commercial 40 refrigeration ton (RT) absorption chiller. While the match between the two ''off the shelf'' units is close and the simulation results are encouraging, the match is not ideal. In particular, the fuel cell exhaust gas temperature is higher than the inlet temperature specified for the chiller and the exhaust flow rate is not sufficient to achieve the potential heat recovery within the chiller heat exchanger. To address these challenges, the study evaluates two strategies: (1) blending the fuel cell exhaust gas with ambient air, and (2) mixing the fuel cell exhaust gases with a fraction of the chiller exhaust gas. Both cases are shown to be viable and result in a temperature drop and flow

  13. A general strategy toward graphitized carbon coating on iron oxides as advanced anodes for lithium-ion batteries.

    Science.gov (United States)

    Ding, Chunyan; Zhou, Weiwei; Wang, Bin; Li, Xin; Wang, Dong; Zhang, Yong; Wen, Guangwu

    2017-08-25

    Integration of carbon materials with benign iron oxides is blazing a trail in constructing high-performance anodes for lithium-ion batteries (LIBs). In this paper, a unique general, simple, and controllable strategy is developed toward in situ uniform coating of iron oxide nanostructures with graphitized carbon (GrC) layers. The basic synthetic procedure only involves a simple dip-coating process for the loading of Ni-containing seeds and a subsequent Ni-catalyzed chemical vapor deposition (CVD) process for the growth of GrC layers. More importantly, the CVD treatment is conducted at a quite low temperature (450 °C) and with extremely facile liquid carbon sources consisting of ethylene glycol (EG) and ethanol (EA). The GrC content of the resulting hybrids can be controllably regulated by altering the amount of carbon sources. The electrochemical results reveal remarkable performance enhancements of iron oxide@GrC hybrids compared with pristine iron oxides in terms of high specific capacity, excellent rate and cycling performance. This can be attributed to the network-like GrC coating, which can improve not only the electronic conductivity but also the structural integrity of iron oxides. Moreover, the lithium storage performance of samples with different GrC contents is measured, manifesting that optimized electrochemical property can be achieved with appropriate carbon content. Additionally, the superiority of GrC coating is demonstrated by the advanced performance of iron oxide@GrC compared with its corresponding counterpart, i.e., iron oxides with amorphous carbon (AmC) coating. All these results indicate the as-proposed protocol of GrC coating may pave the way for iron oxides to be promising anodes for LIBs.

  14. Features of film growth during plasma anodizing of Al 2024/SiC metal matrix composite

    Energy Technology Data Exchange (ETDEWEB)

    Xue Wenbin [Key Laboratory for Radiation Beam Technology and Materials Modification, Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing 100875 (China)]. E-mail: xuewb@bnu.edu.cn

    2006-07-15

    Plasma anodizing is a novel promising process to fabricate corrosion-resistant protective films on metal matrix composites. The corrosion-resistant films were prepared by plasma anodizing on SiC reinforced aluminum matrix composite. The morphology and microstructure of films were analyzed by scanning electron microscopy. Specifically, the morphology of residual SiC reinforcement particles in the film was observed. It is found that the most SiC reinforcement particles have been molten to become silicon oxide, but a few tiny SiC particles still remain in the film close to the composite/film interface. This interface is irregular due to the hindering effect of SiC particles on the film growth. Morphology and distribution of residual SiC particles in film provide direct evidence to identify the local melt occurs in the interior of plasma anodizing film even near the composite/film interface. A model of film growth by plasma anodizing on metal matrix composites was proposed.

  15. Features of film growth during plasma anodizing of Al 2024/SiC metal matrix composite

    International Nuclear Information System (INIS)

    Xue Wenbin

    2006-01-01

    Plasma anodizing is a novel promising process to fabricate corrosion-resistant protective films on metal matrix composites. The corrosion-resistant films were prepared by plasma anodizing on SiC reinforced aluminum matrix composite. The morphology and microstructure of films were analyzed by scanning electron microscopy. Specifically, the morphology of residual SiC reinforcement particles in the film was observed. It is found that the most SiC reinforcement particles have been molten to become silicon oxide, but a few tiny SiC particles still remain in the film close to the composite/film interface. This interface is irregular due to the hindering effect of SiC particles on the film growth. Morphology and distribution of residual SiC particles in film provide direct evidence to identify the local melt occurs in the interior of plasma anodizing film even near the composite/film interface. A model of film growth by plasma anodizing on metal matrix composites was proposed

  16. Low hydrogen containing amorphous carbon films - Growth and electrochemical properties as lithium battery anodes

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, V.; Masarapu, Charan; Wei, Bingqing [Department of Mechanical Engineering, University of Delaware, 130 Academy Street, Newark, DE 19716 (United States); Karabacak, Tansel [Department of Applied Science, University of Arkansas at Little Rock, 2801 South University Avenue, Little Rock, AR 72204 (United States); Teki, Ranganath [Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180 (United States); Lu, Toh-Ming [Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, NY 12180 (United States)

    2010-04-02

    Amorphous carbon films were deposited successfully on Cu foils by DC magnetron sputtering technique. Electrochemical performance of the film as lithium battery anode was evaluated across Li metal at 0.2 C rate in a non-aqueous electrolyte. The discharge curves showed unusually low irreversible capacity in the first cycle with a reversible capacity of {proportional_to}810 mAh g{sup -1}, which is at least 2 times higher than that of graphitic carbon. For the first time we report here an amorphous carbon showing such a high reversibility in the first cycle, which is very much limited to the graphitic carbon. The deposited films were extensively characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and step profilometer for the structural and surface properties. The hydrogen content of the synthesized films was studied using residual gas analysis (RGA). The low hydrogen content and the low specific surface area of the synthesized amorphous carbon film are considered responsible for such a high first cycle columbic efficiency. The growth mechanism and the reasons for enhanced electrochemical performance of the carbon films are discussed. (author)

  17. Low hydrogen containing amorphous carbon films-Growth and electrochemical properties as lithium battery anodes

    Science.gov (United States)

    Subramanian, V.; Karabacak, Tansel; Masarapu, Charan; Teki, Ranganath; Lu, Toh-Ming; Wei, Bingqing

    Amorphous carbon films were deposited successfully on Cu foils by DC magnetron sputtering technique. Electrochemical performance of the film as lithium battery anode was evaluated across Li metal at 0.2 C rate in a non-aqueous electrolyte. The discharge curves showed unusually low irreversible capacity in the first cycle with a reversible capacity of ∼810 mAh g -1, which is at least 2 times higher than that of graphitic carbon. For the first time we report here an amorphous carbon showing such a high reversibility in the first cycle, which is very much limited to the graphitic carbon. The deposited films were extensively characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and step profilometer for the structural and surface properties. The hydrogen content of the synthesized films was studied using residual gas analysis (RGA). The low hydrogen content and the low specific surface area of the synthesized amorphous carbon film are considered responsible for such a high first cycle columbic efficiency. The growth mechanism and the reasons for enhanced electrochemical performance of the carbon films are discussed.

  18. Study of the anodic process in the electrolysis of molten chlorides. Application to the chlorine electrode; Contribution a l'etude du processus anodique dans l'electrolyse des chlorures fondus. Application a l'electrode de chlore

    Energy Technology Data Exchange (ETDEWEB)

    Fondanaiche, J C [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1967-05-01

    The oxidation reaction of Cl{sup -} ions on a carbon electrode occurs with a very low over-voltage in molten LiCl-KCl, NaCl-KCl, CaCl{sub 2} and AgCl electrolytes and therefore the properties of the electrode 'polarized' anodically with a current density I are, as a first approximation, identical to those which it possesses at a chlorine pressure P (produced by the addition of external chlorine). This property of the Cl{sup -} ion oxidation reaction has enabled us to propose an electrochemical method for the study of the absorption equilibrium of the chlorine between a solid and a liquid phase. We can in effect replace this addition of outside chlorine at a pressure P by an electrolysis at a current density I. We have developed a mechanism which accounts for the reaction kinetic of the discharge of Cl{sup -} ions. It has been checked with the help of intensity-potential curves and potential-time curves which characterize the carbon depolarization in an open circuit. Two methods have been used for measuring the amount of chlorine adsorbed on the carbon. It has been possible to determine the nature of the bonds linking the adsorbed chlorine to the carbon, and the electrode-electrolyte surface exchange by varying the temperature and the nature of the electrode and of the electrolyte. Certain anomalies and in particular certain transient phenomena have been explained by the influence of the oxygen present in the molten salt in the form of O{sup 2-} ions and, on the electrode surface, in the form of chemisorption complexes. (author) [French] La reaction d'oxydation des ions Cl{sup -} sur une electrode de carbone s'effectue avec une surtension tres faible dans les electrolytes fondus LiCl-KCl, NaCl-KCl, CaCl{sub 2} et AgCl et par consequent les proprietes de l'electrode ''polarisee'' anodiquement avec une densite de courant I sont, en premiere approximation, identiques a celles qu'elle possede sous une pression de chlore P (creee par un apport exterieur de chlore). Cette

  19. Analysis of a DVR with Molten Carbonate Fuel Cell and Fuzzy Logic Control

    Directory of Open Access Journals (Sweden)

    J. Chakravorty

    2018-04-01

    Full Text Available As power demand constantly (and rapidly increases and with the introduction of many sophisticated electronic devices, power quality issues are becoming a major problem for the power sector. In this context, issues of power quality, voltage swells and sags have become rather common. Custom power devices are generally used to solve this problem. A dynamic voltage restorer (DVR is the most efficient and effective modern custom power device used in power distribution networks. In this paper a new DVR model is presented. The proposed DVR has a molten carbonate fuel cell (MCFC as its DC source of supply with an ultra-capacitor along with a fuzzy controller as its controlling unit. The complete model is implemented in MATLAB/SIMULINK and the output of the proposed model is compared with conventional DVR model with a simple DC voltage source and a capacitor with the same fuzzy controller

  20. Characterization of silicon- and carbon-based composite anodes for lithium-ion batteries

    International Nuclear Information System (INIS)

    Khomenko, Volodymyr G.; Barsukov, Viacheslav Z.

    2007-01-01

    In recent years development of active materials for negative electrodes has been of great interest. Special attention has been focused on the active materials possessing higher reversible capacity than that of conventional graphite. In the present work the electrochemical performance of some carbon/silicon-based materials has been analyzed. For this purpose various silicon-based composites were prepared using such carbon materials as graphite, hard carbon and graphitized carbon black. An analysis of charging-discharging processes at electrodes based on different carbon materials has shown that graphite modified with silicon is the most promising anode material. It has also been revealed that the irreversible capacity mainly depends on the content of Si. An optimum content of Si has been determined with taking into account that high irreversible capacity is not suitable for practical application in lithium-ion batteries. This content falls within the range of 8-10 wt%. The reversible capacity of graphite modified with 8 wt% carbon-coated Si was as high as 604 mAh g -1 . The irreversible capacity loss with this material was as low as 8.1%. The small irreversible capacity of the material allowed developing full lithium-ion rechargeable cells in the 2016 coin cell configuration. Lithium-ion batteries based on graphite modified with silicon show gravimetric and volumetric specific energy densities which are higher by approximately 20% than those for a lithium-ion battery based on natural graphite

  1. Mesostructured niobium-doped titanium oxide-carbon (Nb-TiO2-C) composite as an anode for high-performance lithium-ion batteries

    Science.gov (United States)

    Hwang, Keebum; Sohn, Hiesang; Yoon, Songhun

    2018-02-01

    Mesostructured niobium (Nb)-doped TiO2-carbon (Nb-TiO2-C) composites are synthesized by a hydrothermal process for application as anode materials in Li-ion batteries. The composites have a hierarchical porous structure with the Nb-TiO2 nanoparticles homogenously distributed throughout the porous carbon matrix. The Nb content is controlled (0-10 wt%) to investigate its effect on the physico-chemical properties and electrochemical performance of the composite. While the crystalline/surface structure varied with the addition of Nb (d-spacing of TiO2: 0.34-0.36 nm), the morphology of the composite remained unaffected. The electrochemical performance (cycle stability and rate capability) of the Nb-TiO2-C composite anode with 1 wt% Nb doping improved significantly. First, a full cut-off potential (0-2.5 V vs. Li/Li+) of Nb-doped composite anode (1 wt%) provides a higher energy utilization than that of the un-doped TiO2-C anode. Second, Nb-TiO2-C composite anode (1 wt%) exhibits an excellent long-term cycle stability (100% capacity retention, 297 mAh/g at 0.5 C after 100 cycles and 221 mAh/g at 2 C after 500 cycles) and improved rate-capability (192 mAh/g at 5 C), respectively (1 C: 150 mA/g). The superior electrochemical performance of Nb-TiO2-C (1 wt%) could be attributed to the synergistic effect of improved electronic conductivity induced by optimal Nb doping (1 wt%) and lithium-ion penetration (high diffusion kinetics) through unique pore structures.

  2. From Allergens to Battery Anodes: Nature-Inspired, Pollen Derived Carbon Architectures for Room- and Elevated- Temperature Li-ion Storage

    Science.gov (United States)

    Tang, Jialiang; Pol, Vilas G.

    2016-02-01

    The conversion of allergic pollen grains into carbon microstructures was carried out through a facile, one-step, solid-state pyrolysis process in an inert atmosphere. The as-prepared carbonaceous particles were further air activated at 300 °C and then evaluated as lithium ion battery anodes at room (25 °C) and elevated (50 °C) temperatures. The distinct morphologies of bee pollens and cattail pollens are resembled on the final architecture of produced carbons. Scanning Electron Microscopy images shows that activated bee pollen carbon (ABP) is comprised of spiky, brain-like, and tiny spheres; while activated cattail pollen carbon (ACP) resembles deflated spheres. Structural analysis through X-ray diffraction and Raman spectroscopy confirmed their amorphous nature. X-ray photoelectron spectroscopy analysis of ABP and ACP confirmed that both samples contain high levels of oxygen and small amount of nitrogen contents. At C/10 rate, ACP electrode delivered high specific lithium storage reversible capacities (590 mAh/g at 50 °C and 382 mAh/g at 25 °C) and also exhibited excellent high rate capabilities. Through electrochemical impedance spectroscopy studies, improved performance of ACP is attributed to its lower charge transfer resistance than ABP. Current studies demonstrate that morphologically distinct renewable pollens could produce carbon architectures for anode applications in energy storage devices.

  3. Aluminum low temperature smelting cell metal collection

    Science.gov (United States)

    Beck, Theodore R.; Brown, Craig W.

    2002-07-16

    A method of producing aluminum in an electrolytic cell containing alumina dissolved in an electrolyte. The method comprises the steps of providing a molten salt electrolyte in an electrolytic cell having an anodic liner for containing the electrolyte, the liner having an anodic bottom and walls including at least one end wall extending upwardly from the anodic bottom, the anodic liner being substantially inert with respect to the molten electrolyte. A plurality of non-consumable anodes is provided and disposed vertically in the electrolyte. A plurality of cathodes is disposed vertically in the electrolyte in alternating relationship with the anodes. The anodes are electrically connected to the anodic liner. An electric current is passed through the anodic liner to the anodes, through the electrolyte to the cathodes, and aluminum is deposited on said cathodes. Oxygen bubbles are generated at the anodes and the anodic liner, the bubbles stirring the electrolyte. Molten aluminum is collected from the cathodes into a tubular member positioned underneath the cathodes. The tubular member is in liquid communication with each cathode to collect the molten aluminum therefrom while excluding electrolyte. Molten aluminum is delivered through the tubular member to a molten aluminum reservoir located substantially opposite the anodes and cathodes. The molten aluminum is collected from the cathodes and delivered to the reservoir while avoiding contact of the molten aluminum with the anodic bottom.

  4. Three-Dimensional SnS Decorated Carbon Nano-Networks as Anode Materials for Lithium and Sodium Ion Batteries

    Directory of Open Access Journals (Sweden)

    Yanli Zhou

    2018-02-01

    Full Text Available The three-dimensional (3D SnS decorated carbon nano-networks (SnS@C were synthesized via a facile two-step method of freeze-drying combined with post-heat treatment. The lithium and sodium storage performances of above composites acting as anode materials were investigated. As anode materials for lithium ion batteries, a high reversible capacity of 780 mAh·g−1 for SnS@C composites can be obtained at 100 mA·g−1 after 100 cycles. Even cycled at a high current density of 2 A·g−1, the reversible capacity of this composite can be maintained at 610 mAh·g−1 after 1000 cycles. The initial charge capacity for sodium ion batteries can reach 333 mAh·g−1, and it retains a reversible capacity of 186 mAh·g−1 at 100 mA·g−1 after 100 cycles. The good lithium or sodium storage performances are likely attributed to the synergistic effects of the conductive carbon nano-networks and small SnS nanoparticles.

  5. New High-Energy Nanofiber Anode Materials

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiangwu [North Carolina State Univ., Raleigh, NC (United States); Fedkiw, Peter [North Carolina State Univ., Raleigh, NC (United States); Khan, Saad [North Carolina State Univ., Raleigh, NC (United States); Huang, Alex [North Carolina State Univ., Raleigh, NC (United States); Fan, Jiang [North Carolina State Univ., Raleigh, NC (United States)

    2013-11-15

    The overall goal of the proposed work was to use electrospinning technology to integrate dissimilar materials (lithium alloy and carbon) into novel composite nanofiber anodes, which simultaneously had high energy density, reduced cost, and improved abuse tolerance. The nanofiber structure allowed the anodes to withstand repeated cycles of expansion and contraction. These composite nanofibers were electrospun into nonwoven fabrics with thickness of 50 μm or more, and then directly used as anodes in a lithium-ion battery. This eliminated the presence of non-active materials (e.g., conducting carbon black and polymer binder) and resulted in high energy and power densities. The nonwoven anode structure also provided a large electrode-electrolyte interface and, hence, high rate capacity and good lowtemperature performance capability. Following are detailed objectives for three proposed project periods. During the first six months: Obtain anodes capable of initial specific capacities of 650 mAh/g and achieve ~50 full charge/discharge cycles in small laboratory scale cells (50 to 100 mAh) at the 1C rate with less than 20 percent capacity fade; In the middle of project period: Assemble, cycle, and evaluate 18650 cells using proposed anode materials, and demonstrate practical and useful cycle life (750 cycles of ~70% state of charge swing with less than 20% capacity fade) in 18650 cells with at least twice improvement in the specific capacity than that of conventional graphite electrodes; At the end of project period: Deliver 18650 cells containing proposed anode materials, and achieve specific capacities greater than 1200 mAh/g and cycle life longer than 5000 cycles of ~70% state of charge swing with less than 20% capacity fade.

  6. The mechanics of pressed-pellet separators in molten salt batteries

    Energy Technology Data Exchange (ETDEWEB)

    Long, Kevin Nicholas [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Roberts, Christine Cardinal [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Roberts, Scott Alan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Grillet, Anne [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-06-01

    We present a phenomenological constitutive model that describes the macroscopic behavior of pressed-pellet materials used in molten salt batteries. Such materials include separators, cathodes, and anodes. The purpose of this model is to describe the inelastic deformation associated with the melting of a key constituent, the electrolyte. At room temperature, all constituents of these materials are solid and do not transport cations so that the battery is inert. As the battery is heated, the electrolyte, a constituent typically present in the separator and cathode, melts and conducts charge by flowing through the solid skeletons of the anode, cathode, and separator. The electrochemical circuit is closed in this hot state of the battery. The focus of this report is on the thermal-mechanical behavior of the separator, which typically exhibits the most deformation of the three pellets during the process of activating a molten salt battery. Separator materials are composed of a compressed mixture of a powdered electrolyte, an inert binder phase, and void space. When the electrolyte melts, macroscopically one observes both a change in volume and shape of the separator that depends on the applied boundary conditions during the melt transition. Although porous flow plays a critical role in the battery mechanics and electrochemistry, the focus of this report is on separator behavior under flow-free conditions in which the total mass of electrolyte is static within the pellet. Specific poromechanics effects such as capillary pressure, pressure-saturation, and electrolyte transport between layers are not considered. Instead, a phenomenological model is presented to describe all such behaviors including the melting transition of the electrolyte, loss of void space, and isochoric plasticity associated with the binder phase rearrangement. The model is appropriate for use finite element analysis under finite deformation and finite temperature change conditions. The model

  7. Preparation of pyrolytic carbon coating on graphite for inhibiting liquid fluoride salt and Xe135 penetration for molten salt breeder reactor

    International Nuclear Information System (INIS)

    Song, Jinliang; Zhao, Yanling; He, Xiujie; Zhang, Baoliang; Xu, Li; He, Zhoutong; Zhang, DongSheng; Gao, Lina; Xia, Huihao; Zhou, Xingtai; Huai, Ping; Bai, Shuo

    2015-01-01

    Highlights: • Rough laminar pyrolytic carbon coating (RLPyC) is prepared by a fixed-bed method. • The salt-infiltration into IG-110 is 13.5%, less than 0.01% of RLPyC under 1.5 atm. • The helium diffusion coefficient of RLPyC coated graphite is 2.16 × 10 −8 cm 2 /s. • The coated graphite can inhibit the liquid fluoride salt and Xe 135 penetration. - Abstract: A fixed-bed deposition method was used to prepare rough laminar pyrolytic carbon coating (RLPyC) on graphite for inhibiting liquid fluoride salt and Xe 135 penetration during use in molten salt breeder reactor. The RLPyC coating possessed a graphitization degree of 44% and had good contact with graphite substrate. A high-pressure reactor was constructed to evaluate the molten salt infiltration in the isostatic graphite (IG-110, TOYO TANSO CO., LTD.) and RLPyC coated graphite under 1.01, 1.52, 3.04, 5.07 and 10.13 × 10 5 Pa for 12 h. Mercury injection and molten-salt infiltration experiments indicated the porosity and the salt-infiltration amount of 18.4% and 13.5 wt% under 1.52 × 10 5 Pa of IG-110, which was much less than 1.2% and 0.06 wt% under 10.13 × 10 5 Pa of the RLPyC, respectively. A vacuum device was constructed to evaluate the Xe 135 penetration in the graphite. The helium diffusion coefficient of RLPyC coated graphite was 2.16 × 10 −12 m 2 /s, much less than 1.21 × 10 −6 m 2 /s of the graphite. Thermal cycle experiment indicated the coatings possessed excellent thermal stability. The coated graphite could effectively inhibit the liquid fluoride salt and Xe 135 penetration

  8. Fabrication of carbon microcapsules containing silicon nanoparticles-carbon nanotubes nanocomposite by sol-gel method for anode in lithium ion battery

    Science.gov (United States)

    Bae, Joonwon

    2011-07-01

    Carbon microcapsules containing silicon nanoparticles (Si NPs)-carbon nanotubes (CNTs) nanocomposite (Si-CNT@C) have been fabricated by a surfactant mediated sol-gel method followed by a carbonization process. Silicon nanoparticles-carbon nanotubes (Si-CNT) nanohybrids were produced by a wet-type beadsmill method. To obtain Si-CNT nanocomposites with spherical morphologies, a silica precursor (tetraethylorthosilicate, TEOS) and polymer (PMMA) mixture was employed as a structure-directing medium. Thus the Si-CNT/Silica-Polymer microspheres were prepared by an acid catalyzed sol-gel method. Then a carbon precursor such as polypyrrole (PPy) was incorporated onto the surfaces of pre-existing Si-CNT/silica-polymer to generate Si-CNT/Silica-Polymer@PPy microspheres. Subsequent thermal treatment of the precursor followed by wet etching of silica produced Si-CNT@C microcapsules. The intermediate silica/polymer must disappear during the carbonization and etching process resulting in the formation of an internal free space. The carbon precursor polymer should transform to carbon shell to encapsulate remaining Si-CNT nanocomposites. Therefore, hollow carbon microcapsules containing Si-CNT nanocomposites could be obtained (Si-CNT@C). The successful fabrication was confirmed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). These final materials were employed for anode performance improvement in lithium ion battery. The cyclic performances of these Si-CNT@C microcapsules were measured with a lithium battery half cell tests.

  9. Carbon-coated mesoporous SnO2 nanospheres as anode material for lithium ion batteries

    International Nuclear Information System (INIS)

    Wang, Fei; Song, Xiaoping; Yao, Gang; Zhao, Mingshu; Liu, Rui; Xu, Minwei; Sun, Zhanbo

    2012-01-01

    In this paper mesoporous SnO 2 nanospheres with an average diameter of about 83 nm, composed of many tiny primary particles (∼10 nm) and holes, are synthesized on a large scale by a simple hydrothermal route. The as-prepared mesoporous SnO 2 nanospheres were uniformly coated with carbon by a further hydrothermal treatment in glucose aqueous solution. As anode materials for lithium-ion batteries, the core–shell SnO 2 /C nanocomposites exhibit a markedly improved cycling performance.

  10. Accelerator molten-salt breeder reactor

    International Nuclear Information System (INIS)

    Furukawa, Kazuo; Kuroi, Hideo; Kato, Yoshio; Oomichi, Toshihiko.

    1979-01-01

    Purpose: To obtain fission products and to transmute transuranium elements and other radioactive wastes by the use of Accelerator Molten-Salt Breeder Reactor. Constitution: Beams from an accelerator pipe at one end of a target vessel is injected through a window into target molten salts filled inside of the target vessel. The target molten salts are subjected to pump recycling or spontaneous convection while forcively cooled by blanket molten salts in an outer vessel. Then, energy is recovered from the blanket molten salts or the target molten salts at high temperatures through electric power generation or the like. Those salts containing such as thorium 232 and uranium 238 are used as the blanket molten salts so that fission products may be produced by neutrons generated in the target molten salts. PbCl 2 -PbF 2 and LiF-BeF 2 -ThF 4 can be used as the target molten salts and as the blanket molten salts respectively. (Seki, T.)

  11. Pyrolytic carbon-coated stainless steel felt as a high-performance anode for bioelectrochemical systems.

    Science.gov (United States)

    Guo, Kun; Hidalgo, Diana; Tommasi, Tonia; Rabaey, Korneel

    2016-07-01

    Scale up of bioelectrochemical systems (BESs) requires highly conductive, biocompatible and stable electrodes. Here we present pyrolytic carbon-coated stainless steel felt (C-SS felt) as a high-performance and scalable anode. The electrode is created by generating a carbon layer on stainless steel felt (SS felt) via a multi-step deposition process involving α-d-glucose impregnation, caramelization, and pyrolysis. Physicochemical characterizations of the surface elucidate that a thin (20±5μm) and homogenous layer of polycrystalline graphitic carbon was obtained on SS felt surface after modification. The carbon coating significantly increases the biocompatibility, enabling robust electroactive biofilm formation. The C-SS felt electrodes reach current densities (jmax) of 3.65±0.14mA/cm(2) within 7days of operation, which is 11 times higher than plain SS felt electrodes (0.30±0.04mA/cm(2)). The excellent biocompatibility, high specific surface area, high conductivity, good mechanical strength, and low cost make C-SS felt a promising electrode for BESs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Advanced Thermal Storage System with Novel Molten Salt: December 8, 2011 - April 30, 2013

    Energy Technology Data Exchange (ETDEWEB)

    Jonemann, M.

    2013-05-01

    Final technical progress report of Halotechnics Subcontract No. NEU-2-11979-01. Halotechnics has demonstrated an advanced thermal energy storage system with a novel molten salt operating at 700 degrees C. The molten salt and storage system will enable the use of advanced power cycles such as supercritical steam and supercritical carbon dioxide in next generation CSP plants. The salt consists of low cost, earth abundant materials.

  13. Development of molten carbonate fuel cell technology at M-C Power Corporation

    Energy Technology Data Exchange (ETDEWEB)

    Dilger, D. [M-C Power Corp., Burr Ridge, IL (United States)

    1996-04-01

    M-C Power Corporation was founded in 1987 with the mission to further develop and subsequently commercialize molten carbonate fuel cells (MCFC). The technology chosen for commercialization was initially developed by the Institute of Gas technology (IGT). At the center of this MCFC technology is the Internally Manifolded Heat EXchange (IMHEX) separator plate design. The IMHEX technology design provides several functions within one component assembly. These functions include integrating the gas manifold structure into the fuel cell stack, separating the fuel gas stream from the oxidant gas stream, providing the required electrical contact between cells to achieve desired power output, and removing excess heat generated in the electrochemical process. Development of this MCFC technology from lab-scale sizes too a commercial area size of 1m{sup 2} has focused our efforts an demonstrating feasibility and evolutionary progress. The development effort will culminate in a proof-of-concept- 250kW power plant demonstration in 1996. The remainder of our commercialization program focuses upon lowering the costs associated with the MCFC power plant system in low production volumes.

  14. Molten salt combustion of radioactive wastes

    International Nuclear Information System (INIS)

    Grantham, L.F.; McKenzie, D.E.; Richards, W.L.; Oldenkamp, R.D.

    1976-01-01

    The Atomics International Molten Salt Combustion Process reduces the weight and volume of combustible β-γ contaminated transuranic waste by utilizing air in a molten salt medium to combust organic materials, to trap particulates, and to react chemically with any acidic gases produced during combustion. Typically, incomplete combustion products such as hydrocarbons and carbon monoxide are below detection limits (i.e., 3 ) is directly related to the sodium chloride vapor pressure of the melt; >80% of the particulate is sodium chloride. Essentially all metal oxides (combustion ash) are retained in the melt, e.g., >99.9% of the plutonium, >99.6% of the europium, and >99.9% of the ruthenium are retained in the melt. Both bench-scale radioactive and pilot scale (50 kg/hr) nonradioactive combustion tests have been completed with essentially the same results. Design of three combustors for industrial applications are underway

  15. The anodic dissolution of SIMFUEL (UO2) in slightly alkaline sodium carbonate/bicarbonate solutions

    International Nuclear Information System (INIS)

    Keech, P.G.; Goldik, J.S.; Qin, Z.; Shoesmith, D.W.

    2011-01-01

    The corrosion of nuclear fuel under waste disposal conditions is likely to be influenced by the bicarbonate/carbonate content of the groundwater since it increases the solubility of the U VI corrosion product, [UO 2 ] 2+ . As one of the half reactions involved in the corrosion process, the anodic dissolution of SIMFUEL (UO 2 ) has been studied in bicarbonate/carbonate solutions (pH 9.8) using voltammetric and potentiostatic techniques and electrochemical impedance spectroscopy. The reaction proceeds by two consecutive one electron transfer reactions (U IV → U V → U VI ). At low potentials (≤250 mV (vs. SCE) the rate of the first electron transfer reaction is rate determining irrespective of the total carbonate concentration. At potentials >250 mV (vs. SCE) the formation of a U VI O 2 CO 3 surface layer begins to inhibit the dissolution rate and the current becomes independent of potential indicating rate control by the chemical dissolution of this layer.

  16. Solution-Grown Silicon Nanowires for Lithium-Ion Battery Anodes

    KAUST Repository

    Chan, Candace K.; Patel, Reken N.; O’ Connell, Michael J.; Korgel, Brian A.; Cui, Yi

    2010-01-01

    Composite electrodes composed of silicon nanowires synthesized using the supercritical fluid-liquid-solid (SFLS) method mixed with amorphous carbon or carbon nanotubes were evaluated as Li-ion battery anodes. Carbon coating of the silicon nanowires

  17. OPTIMIZATION OF THE CATHODE LONG-TERM STABILITY IN MOLTEN CARBONATE FUEL CELLS: EXPERIMENTAL STUDY AND MATHEMATICAL MODELING

    Energy Technology Data Exchange (ETDEWEB)

    Hector Colonmer; Prabhu Ganesan; Nalini Subramanian; Dr. Bala Haran; Dr. Ralph E. White; Dr. Branko N. Popov

    2002-09-01

    This project focused on addressing the two main problems associated with state of art Molten Carbonate Fuel Cells, namely loss of cathode active material and stainless steel current collector deterioration due to corrosion. We followed a dual approach where in the first case we developed novel materials to replace the cathode and current collector currently used in molten carbonate fuel cells. In the second case we improved the performance of conventional cathode and current collectors through surface modification. States of art NiO cathode in MCFC undergo dissolution in the cathode melt thereby limiting the lifetime of the cell. To prevent this we deposited cobalt using an electroless deposition process. We also coated perovskite (La{sub 0.8}Sr{sub 0.2}CoO{sub 3}) in NiO thorough a sol-gel process. The electrochemical oxidation behavior of Co and perovskites coated electrodes is similar to that of the bare NiO cathode. Co and perovskite coatings on the surface decrease the dissolution of Ni into the melt and thereby stabilize the cathode. Both, cobalt and provskites coated nickel oxide, show a higher polarization compared to that of nickel oxide, which could be due to the reduced surface area. Cobalt substituted lithium nickel oxide (LiNi{sub 0.8}Co{sub 0.2}O{sub 2}) and lithium cobalt oxide were also studied. LiNi{sub x}Co{sub 1-x}O{sub 2} was synthesized by solid-state reaction procedure using lithium nitrate, nickel hydroxide and cobalt oxalate precursor. LiNi{sub x}Co{sub 1-x}O{sub 2} showed smaller dissolution of nickel than state of art nickel oxide cathode. The performance was comparable to that of nickel oxide. The corrosion of the current collector in the cathode side was also studied. The corrosion characteristics of both SS304 and SS304 coated with Co-Ni alloy were studied. This study confirms that surface modification of SS304 leads to the formation of complex scales with better barrier properties and better electronic conductivity at 650 C. A three

  18. Performance of molten carbonate fuel cells with the electrolyte molded at low pressure (3) The stability of anode microlayers

    Energy Technology Data Exchange (ETDEWEB)

    Sonai, Atsuo; Suzuki, Nobukazu; Murata, Kenji; Shirogami, Tamotsu

    1987-01-01

    It is known that an addition of organic binder to the electrolyte layer which composes a fuel cell enables to produce a large plate of electrolyte even in low temperature and low pressure conditions. However, when the binder is volatilized, bores remain making poor performance as a sepa-rator plate of the reacting gas. In order to prevent the gas permeation, it is necessary to combine a double layered electrode with microporous layers on the electrode surface ajacent to the electrolyte layer. In this study, stability of microporous layers of the anode electrode was examined, and it was found that the microporous layers made by sintering Ni-powders was unstable and dissoluted, but the impregnation of such second element as Chromium oxide, Yttrium oxide, Aluminum oxide into the layer improved the stability. (10 figs, 1 tab, 6 refs)

  19. Construction of carbon nanoflakes shell on CuO nanowires core as enhanced core/shell arrays anode of lithium ion batteries

    International Nuclear Information System (INIS)

    Cao, F.; Xia, X.H.; Pan, G.X.; Chen, J.; Zhang, Y.J.

    2015-01-01

    Highlights: • CuO/C core/shell nanowire arrays are prepared by electro-deposition + ALD method. • Carbon shell is favorable for structural stability. • CuO/C core/shell arrays show enhanced cycle stability and high capacity. - Abstract: Tailored metal oxide/carbon composite structures have attracted great attention due to potential synergistic effects and enhanced properties. In this work, novel CuO/C core/shell nanowire arrays are prepared by the combination of electro-deposition of CuO and atomic-layer-deposition-assisted formation of carbon nanoflakes shell. The CuO nanowires with diameters of ∼200 nm are homogenously coated by carbon nanoflakes shell. When evaluated as anode materials for lithium ion batteries (LIBs), compared to the unmodified CuO nanowire arrays, the CuO/C core/shell nanowire arrays exhibit improved electrochemical performances with higher capacity, better electrochemical reactivity and high-rate capability as well as superior cycling life (610 mAh g"−"1 at 0.5C after 290 cycles). The enhanced electrochemical performance is mainly attributed to the introduction of carbon flake shell in the core/shell nanowire arrays structure, which provides higher active material-electrolyte contact area, improved electrical conductivity, and better accommodation of volume change. The proposed method provides a new way for fabrication of high-performance metal oxides anodes of LIBs.

  20. On the Predictions of Carbon Deposition on the Nickel Anode of a SOFC and Its Impact on Open-Circuit Conditions

    KAUST Repository

    Lee, W. Y.

    2012-12-04

    Previous thermodynamic analyses of carbon formation in SOFCs assumed that graphite could be used to represent the properties of carbon formed in the anode. It is generally observed, however, that catalytically grown carbon nanofibers (CNF) are more likely to form in the SOFC anode with nickel catalysts. The energetic and entropic properties of CNF are different from those of graphite.We compare equilibrium results based on thermochemical properties for graphite, to new results based on a previously reported value of an empirically determined Gibbs free energy for carbon fibers grown on a nickel support (with fitted values of H°CNF = 54.46 kJ/mol and S°CNF = 68.90 J/mol/K for a nickel crystal size of 5.4 nm). There is little difference in predictions of carbon formation under open-circuit conditions between the two carbon types for methane mixtures, with graphite predicted to form at lower temperatures than CNF. There is a much bigger difference in predictions for methanol mixtures, especially at low steam-carbon ratios. The differences for propane are even more pronounced, and the improved predictions assuming CNF are in closer agreement with past observations.We show a strong dependence of CNF formation and "coking threshold" on nickel crystallite size, supporting previous reports that the nickel particle size is a dominating parameter for controlling filament growth. If both carbon types are included in the calculations, only the thermodynamically favored form (i.e., the type having the lowest formation energy) exists. Predicted Nernst potentials are more-or-less independent of the carbon type and in agreement with measured open-circuit voltages. © 2012 The Electrochemical Society.

  1. Recovery Of Valuable Metals In Tin-Based Anodic Slimes By Carbothermic Reaction

    Directory of Open Access Journals (Sweden)

    Han Chulwoong

    2015-06-01

    Full Text Available This study investigated the recovery of anodic slimes by carbothermic reaction in the temperature range of 973~1,273K and amount of carbon as a function of time. Tin anodic slime samples were collected from the bottom of the electrolytic cells during the electro-refining of tin. The anodic slimes are consisted of high concentrated tin, silver, copper and lead oxides. The kinetics of reduction were determined by means of the weight-loss measurement technique. In order to understand in detail of carbothermic reaction, thermodynamic calculation was carried out and compared with experiments. From thermodynamic calculation and experiment, it was confirmed that Sn-based anodic slime could be reduced by controlling temperature and amount of carbon. However, any tendency between the reduction temperature and carbon content for the reduction reaction was not observed.

  2. Preparation of pyrolytic carbon coating on graphite for inhibiting liquid fluoride salt and Xe{sup 135} penetration for molten salt breeder reactor

    Energy Technology Data Exchange (ETDEWEB)

    Song, Jinliang [Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Zhao, Yanling, E-mail: jlsong1982@yeah.net [School of Materials Science and Engineering, University of Jinan, Jinan 250022 (China); He, Xiujie; Zhang, Baoliang [Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Xu, Li [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); He, Zhoutong; Zhang, DongSheng; Gao, Lina; Xia, Huihao; Zhou, Xingtai; Huai, Ping [Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Bai, Shuo [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China)

    2015-01-15

    Highlights: • Rough laminar pyrolytic carbon coating (RLPyC) is prepared by a fixed-bed method. • The salt-infiltration into IG-110 is 13.5%, less than 0.01% of RLPyC under 1.5 atm. • The helium diffusion coefficient of RLPyC coated graphite is 2.16 × 10{sup −8} cm{sup 2}/s. • The coated graphite can inhibit the liquid fluoride salt and Xe{sup 135} penetration. - Abstract: A fixed-bed deposition method was used to prepare rough laminar pyrolytic carbon coating (RLPyC) on graphite for inhibiting liquid fluoride salt and Xe{sup 135} penetration during use in molten salt breeder reactor. The RLPyC coating possessed a graphitization degree of 44% and had good contact with graphite substrate. A high-pressure reactor was constructed to evaluate the molten salt infiltration in the isostatic graphite (IG-110, TOYO TANSO CO., LTD.) and RLPyC coated graphite under 1.01, 1.52, 3.04, 5.07 and 10.13 × 10{sup 5} Pa for 12 h. Mercury injection and molten-salt infiltration experiments indicated the porosity and the salt-infiltration amount of 18.4% and 13.5 wt% under 1.52 × 10{sup 5} Pa of IG-110, which was much less than 1.2% and 0.06 wt% under 10.13 × 10{sup 5} Pa of the RLPyC, respectively. A vacuum device was constructed to evaluate the Xe{sup 135} penetration in the graphite. The helium diffusion coefficient of RLPyC coated graphite was 2.16 × 10{sup −12} m{sup 2}/s, much less than 1.21 × 10{sup −6} m{sup 2}/s of the graphite. Thermal cycle experiment indicated the coatings possessed excellent thermal stability. The coated graphite could effectively inhibit the liquid fluoride salt and Xe{sup 135} penetration.

  3. Improved lithium-ion battery anode capacity with a network of easily fabricated spindle-like carbon nanofibers.

    Science.gov (United States)

    Liu, Mengting; Xie, Wenhe; Gu, Lili; Qin, Tianfeng; Hou, Xiaoyi; He, Deyan

    2016-01-01

    A novel network of spindle-like carbon nanofibers was fabricated via a simplified synthesis involving electrospinning followed by preoxidation in air and postcarbonization in Ar. Not only was the as-obtained carbon network comprised of beads of spindle-like nanofibers but the cubic MnO phase and N elements were successfully anchored into the amorphous carbon matrix. When directly used as a binder-free anode for lithium-ion batteries, the network showed excellent electrochemical performance with high capacity, good rate capacity and reliable cycling stability. Under a current density of 0.2 A g -1 , it delivered a high reversible capacity of 875.5 mAh g -1 after 200 cycles and 1005.5 mAh g -1 after 250 cycles with a significant coulombic efficiency of 99.5%.

  4. Carbon-based coating containing ultrafine MoO2 nanoparticles as an integrated anode for high-performance lithium-ion batteries

    Science.gov (United States)

    Li, Quanyi; Yang, Qi; Zhao, Yanhong; Wan, Bin

    2017-10-01

    Copper-supported MoO2-C composite as an integrated anode with excellent battery performance was synthesized by a facile knife coating technique followed by heat treatment in a vacuum. The obtained samples were characterized by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), thermal analysis, nitrogen adsorption and desorption analysis, field emission scanning microscopy (FESEM), and transmission electron microscopy (TEM). The results show the MoO2-C composite coating is comprised of a porous carbon matrix with a pore size of 1-3 nm and ultrafine MoO2 nanoparticles with a size of 5-10 nm encapsulated inside, the coating is tightly attached on the surface of copper foil, and the interface between them is free of cracks. Stable PAN-DMF-H2O system containing ammonium molybdate suitable for knife coating technique and the MoO2-C composite with ultrafine MoO2 nanoparticles encapsulated in the carbon matrix can be prepared through controlling amount of added ammonium molybdate solution. The copper-supported MoO2-C composite coating can be directly utilized as the integrated anode for lithium-ion batteries (LIBs). It delivers a capacity of 814 mA h g-1 at a current density of 100 mA g-1 after 100 cycles without apparent capacity fading. Furthermore, with increase of current densities to 200, 500, 1000, 2000, and 5000 mA g-1, it exhibits average capacities of 809, 697, 568, 383, and 188 mA h g-1. Its outstanding electrochemical performance is attributed to combined merits of integrated anode and structure with ultrafine MoO2 nanoparticles embedded in the porous carbon matrix.

  5. Molten salt breeder reactor

    International Nuclear Information System (INIS)

    1977-01-01

    MSBR Study Group formed in October 1974 has studied molten salt breeder reactor and its various aspects. Usage of a molten salt fuel, extremely interesting as reactor chemistry, is a great feature to MSBR; there is no need for separate fuel making, reprocessing, waste storage facilities. The group studied the following, and these results are presented: molten salt technology, molten salt fuel chemistry and reprocessing, reactor characteristics, economy, reactor structural materials, etc. (Mori, K.)

  6. Modelling of crater formation on anode surface by high-current vacuum arcs

    Science.gov (United States)

    Tian, Yunbo; Wang, Zhenxing; Jiang, Yanjun; Ma, Hui; Liu, Zhiyuan; Geng, Yingsan; Wang, Jianhua; Nordlund, Kai; Djurabekova, Flyura

    2016-11-01

    Anode melting and crater formation significantly affect interruption of high-current vacuum arcs. The primary objective of this paper is to theoretically investigate the mechanism of anode surface crater formation, caused by the combined effect of surface heating during the vacuum arc and pressure exerted on the molten surface by ions and electrons from the arc plasma. A model of fluid flow and heat transfer in the arc anode is developed and combined with a magnetohydrodynamics model of the vacuum arc plasma. Crater formation is observed in simulation for a peak arcing current higher than 15 kA on 40 mm diam. Cu electrodes spaced 10 mm apart. The flow of liquid metal starts after 4 or 5 ms of arcing, and the maximum velocities are 0.95 m/s and 1.39 m/s for 20 kA and 25 kA arcs, respectively. This flow redistributes thermal energy, and the maximum temperature of the anode surface does not remain in the center. Moreover, the condition for the liquid droplet formation on the anode surfaces is developed. The solidification process after current zero is also analyzed. The solidification time has been found to be more than 3 ms after 25 kA arcing. The long solidification time and sharp features on crater rims induce Taylor cone formation.

  7. Facile Synthesis of Carbon-Coated Spinel Li4Ti5O12/Rutile-TiO2 Composites as an Improved Anode Material in Full Lithium-Ion Batteries with LiFePO4@N-Doped Carbon Cathode.

    Science.gov (United States)

    Wang, Ping; Zhang, Geng; Cheng, Jian; You, Ya; Li, Yong-Ke; Ding, Cong; Gu, Jiang-Jiang; Zheng, Xin-Sheng; Zhang, Chao-Feng; Cao, Fei-Fei

    2017-02-22

    The spinel Li 4 Ti 5 O 12 /rutile-TiO 2 @carbon (LTO-RTO@C) composites were fabricated via a hydrothermal method combined with calcination treatment employing glucose as carbon source. The carbon coating layer and the in situ formed rutile-TiO 2 can effectively enhance the electric conductivity and provide quick Li + diffusion pathways for Li 4 Ti 5 O 12 . When used as an anode material for lithium-ion batteries, the rate capability and cycling stability of LTO-RTO@C composites were improved in comparison with those of pure Li 4 Ti 5 O 12 or Li 4 Ti 5 O 12 /rutile-TiO 2 . Moreover, the potential of approximately 1.8 V rechargeable full lithium-ion batteries has been achieved by utilizing an LTO-RTO@C anode and a LiFePO 4 @N-doped carbon cathode.

  8. Synthesis and electrochemical performance of mesoporous SiO{sub 2}–carbon nanofibers composite as anode materials for lithium secondary batteries

    Energy Technology Data Exchange (ETDEWEB)

    Hyun, Yura; Choi, Jin-Yeong [Department of Chemistry, Keimyung University (Korea, Republic of); Park, Heai-Ku [Department of Chemical Engineering, Keimyung University (Korea, Republic of); Bae, Jae Young [Department of Chemistry, Keimyung University (Korea, Republic of); Lee, Chang-Seop, E-mail: surfkm@kmu.ac.kr [Department of Chemistry, Keimyung University (Korea, Republic of)

    2016-10-15

    Highlights: • Mesoporous SiO{sub 2}–carbon nanofibers composite synthesized on Ni foam without any binder. • This composite was directly applied as anode material of Li secondary batteries. • Showed the highest initial (2420 mAh/g) and discharging (2092 mAh/g) capacity. • This material achieved a retention rate of 86.4% after 30 cycles. - Abstract: In this study, carbon nanofibers (CNFs) and mesoporous SiO{sub 2}–carbon nanofibers composite were synthesized and applied as the anode materials in lithium secondary batteries. CNFs and mesoporous SiO{sub 2}–CNFs composite were grown via chemical vapor deposition method with iron-copper catalysts. Mesoporous SiO{sub 2} materials were prepared by sol–gel method using tetraethylorthosilicate as the silica source and cetyltrimethylammoniumchloride as the template. Ethylene was used as the carbon source and passes into a quartz reactor of a tube furnace heated to 600 °C, and the temperature was maintained at 600 °C for 10 min to synthesize CNFs and mesoporous SiO{sub 2}–CNFs composite. The electrochemical characteristics of the as-prepared CNFs and mesoporous SiO{sub 2}–CNFs composite as the anode of lithium secondary batteries were investigated using a three-electrode cell. In particular, the mesoporous SiO{sub 2}–CNFs composites synthesized without binder after depositing mesoporous SiO{sub 2} on Ni foam showed the highest charging and discharging capacity and retention rate. The initial capacity (2420 mAh/g) of mesoporous SiO{sub 2}–CNFs composites decreased to 2092 mAh/g after 30 cycles at a retention rate of 86.4%.

  9. Preparation of Carbon-Encapsulated ZnO Tetrahedron as an Anode Material for Ultralong Cycle Life Performance Lithium-ion Batteries

    International Nuclear Information System (INIS)

    Ren, Zhimin; Wang, Zhiyu; Chen, Chao; Wang, Jia; Fu, Xinxin; Fan, Chenyao; Qian, Guodong

    2014-01-01

    Highlights: • A novel architecture of 3D carbon framework to encapsulate ZnO nanocrystals was prepared. • The ZnO@C exhibits ultralong cycle life and high specific capacity when was used as anode. • The in situ carbonization leads to a strong connection between the carbon and ZnO. - ABSTRACT: In this paper we report a novel architecture of three-dimension (3D) carbon framework to encapsulate tetrahedron ZnO nanocrystals that serves as an anode material for lithium-ion batteries (LIBs). The ZnO@C composites are prepared via a simple internal-reflux method combined with subsequent calcination in argon. The amorphous carbon is formed on the surface of the ZnO crystals by in situ carbonization of the surfactant, which leads to a strong connection between the carbon framework and the active materials and guarantees faster charge transfer on the electrode. The ZnO crystal calcined at 500°C (ZnO@C-5) possesses regular tetrahedron shape with a side length of 150-200 nm and all of them are uniformly anchored among the network of amorphous carbon. The developed ZnO@C structures not only improve the electronic conductivity of the electrode, but they also offer a larger volume expansion of ZnO during cycling. As a result, the ZnO@C-5 demonstrates a higher reversible capacity, ultralong cycle life and better rate capability than that of the ZnO@C-7 and pure ZnO crystals. After 300 cycles, the ZnO@C-5 demonstrates a high capacity of 518 mAhg −1 at a current density of 110.7 mAg −1 . Moreover, this simple approach prepared the 3D composites architecture could shed light on the design and synthesis of other transition metal oxides for energy storage

  10. Preparation of tantalum carbide layers on carbon using the metalliding process

    Energy Technology Data Exchange (ETDEWEB)

    Massot, L. [Laboratoire de Genie Chimique UMR 5503, Departement Procedes Electrochimiques, Universite Paul Sabatier, 31062 Toulouse Cedex 9 (France)], E-mail: massot@chimie.ups-tlse.fr; Chamelot, P. [Laboratoire de Genie Chimique UMR 5503, Departement Procedes Electrochimiques, Universite Paul Sabatier, 31062 Toulouse Cedex 9 (France); Winterton, P. [UFR Langues vivantes, Universite Paul Sabatier, 31062 Toulouse Cedex 9 (France); Taxil, P. [Laboratoire de Genie Chimique UMR 5503, Departement Procedes Electrochimiques, Universite Paul Sabatier, 31062 Toulouse Cedex 9 (France)

    2009-03-05

    This work concerns the preparation of tantalum carbide films on carbon-based substrates using the metalliding process in LiF/NaF molten medium (60-40 mol%), containing tantalum heptafluorotantalate ions TaF{sub 7}{sup 2-}, in the 800-900 deg. C temperature range. The process uses a metalliding cell symbolised as: (+) C, TaC{sub x}/LiF-NaF-K{sub 2}TaF{sub 7}/Ta (-) involving the dissolution of Ta at the anode and the reduction of Ta ions in TaC{sub x} at the cathode. The experiments of this process were performed with different carbon substrates as cathodic material: graphite, glassy carbon and carbon braid. Samples analysis (SEM-EDS and XRD) after metalliding showed the formation of tantalum carbides (TaC and Ta{sub 2}C) at the surface of the substrate at a relatively low temperature. A kinetic study, based on the control of the cathodic reaction by the intermetallic diffusion, allowed the diffusion parameters, such as Ta/C diffusion coefficient, to be determined at several temperatures. Furthermore, the results are shown to be independent of the type of carbon substrate.

  11. Selectivity control of carbonylation of methanol to dimethyl oxalate and dimethyl carbonate over gold anode by electrochemical potential.

    Science.gov (United States)

    Funakawa, Akiyasu; Yamanaka, Ichiro; Takenaka, Sakae; Otsuka, Kiyoshi

    2004-05-05

    New and unique electrocatalysis of gold for the carbonylation of methanol to dimethyl oxalate (DMO) and dimethyl carbonate (DMC) was found. The selectivity to DMO and DMC could be controlled over gold anode by electrochemical potential, as you like. Drastic changes of gold electrocatalysis was due to changes of the oxidation state of gold, Au0 or Au3+.

  12. Coulometric thermometric titration of halides in molten calcium nitrate tetrahydrate.

    Science.gov (United States)

    Zsigrai, I J; Bartusz, D B

    1983-01-01

    A method for coulometric thermometric precipitation titrations of chloride, bromide and iodide in molten calcium nitrate tetrahydrate at 55 degrees with coulometrically generated silver ions has been developed. The change in temperature during the titration is followed with the aid of a thermistor bridge coupled to a recorder. To minimize the temperature effect of the passage of current through the melt, two thermistors are connected in opposition in the bridge, with one in the anodic and the other in the cathodic cell compartment. Amounts of 62-80 mumole of halide have been determined with relative error below 0.4% and relative standard deviation less than 2.7%. The relative error in determination of 40 mumole of iodide was + 2%.

  13. Graphene oxide-multiwalled carbon nanotubes composite as an anode for lithium ion batteries

    Directory of Open Access Journals (Sweden)

    Majchrzycki Łukasz

    2016-09-01

    Full Text Available Nowadays reduced graphene oxide (rGO is regarded as a highly interesting material which is appropriate for possible applications in electrochemistry, especially in lithium-ion batteries (LIBs. Several methods were proposed for the preparation of rGO-based electrodes, resulting in high-capacity LIBs anodes. However, the mechanism of lithium storage in rGO and related materials is still not well understood. In this work we focused on the proposed mechanism of favorable bonding sites induced by additional functionalities attached to the graphene planes. This mechanism might increase the capacity of electrodes. In order to verify this hypothesis the composite of non-reduced graphene oxide (GO with multiwalled carbon nanotubes electrodes was fabricated. Electrochemical properties of GO composite anodes were studied in comparison with similarly prepared electrodes based on rGO. This allowed us to estimate the impact of functional groups on the reversible capacity changes. As a result, it was shown that oxygen containing functional groups of GO do not create, in noticeable way, additional active sites for the electrochemical reactions of lithium storage, contrary to what has been postulated previously.

  14. Fabrication of ZnO Nanowires Arrays by Anodization and High-Vacuum Die Casting Technique, and Their Piezoelectric Properties

    Science.gov (United States)

    Kuo, Chin-Guo; Chang, Ho; Wang, Jian-Hao

    2016-01-01

    In this investigation, anodic aluminum oxide (AAO) with arrayed and regularly arranged nanopores is used as a template in the high-vacuum die casting of molten zinc metal (Zn) into the nanopores. The proposed technique yields arrayed Zn nanowires with an aspect ratio of over 600. After annealing, arrayed zinc oxide (ZnO) nanowires are obtained. Varying the anodizing time yields AAO templates with thicknesses of approximately 50 μm, 60 μm, and 70 μm that can be used in the fabrication of nanowires of three lengths with high aspect ratios. Experimental results reveal that a longer nanowire generates a greater measured piezoelectric current. The ZnO nanowires that are fabricated using an alumina template are anodized for 7 h and produce higher piezoelectric current of up to 69 pA. PMID:27023546

  15. Fabrication of ZnO Nanowires Arrays by Anodization and High-Vacuum Die Casting Technique, and Their Piezoelectric Properties.

    Science.gov (United States)

    Kuo, Chin-Guo; Chang, Ho; Wang, Jian-Hao

    2016-03-24

    In this investigation, anodic aluminum oxide (AAO) with arrayed and regularly arranged nanopores is used as a template in the high-vacuum die casting of molten zinc metal (Zn) into the nanopores. The proposed technique yields arrayed Zn nanowires with an aspect ratio of over 600. After annealing, arrayed zinc oxide (ZnO) nanowires are obtained. Varying the anodizing time yields AAO templates with thicknesses of approximately 50 μm, 60 μm, and 70 μm that can be used in the fabrication of nanowires of three lengths with high aspect ratios. Experimental results reveal that a longer nanowire generates a greater measured piezoelectric current. The ZnO nanowires that are fabricated using an alumina template are anodized for 7 h and produce higher piezoelectric current of up to 69 pA.

  16. Compatibility of potential containment materials with molten lithium hydride at 800 C

    International Nuclear Information System (INIS)

    Pawel, S.J.

    1993-01-01

    A series of compatibility experiments has been performed for several stainless steels, carbon steels, and a nickel-base alloy in molten lithium hydride at 800 C for comparison with previous experiments on type 304L stainless steel. The results indicate that the mechanism of corrosion is the same for each of 304L, 304, 316L, and 309 stainless steel and that very similar corrosion in molten LiH is expected for each stainless alloy. Deviation from parabolic kinetics at extended exposure time for each stainless alloy is attributed in part to weight gains associated with lithium penetration. Stabilized (Nb and Ti) low carbon (< 0.06%) steels are observed to be essentially inert in LiH at 800 C with stable carbides and no grain growth. Mild steel (type 1020) is decarburized rapidly and exhibits extensive grain growth in LiH at 800 C. Both steels exhibit weight gains during exposure to molten LiH that are also related in part to lithium penetration. Alloy X (UNS N06002) exhibits extreme corrosion with essentially linear kinetics and dissolution of nickel sufficient to form subsurface voids. (orig.)

  17. Redox Stable Anodes for Solid Oxide Fuel Cells

    Directory of Open Access Journals (Sweden)

    Guoliang eXiao

    2014-06-01

    Full Text Available Solid oxide fuel cells (SOFCs can convert chemical energy from the fuel directly to electrical energy with high efficiency and fuel flexibility. Ni-based cermets have been the most widely adopted anode for SOFCs. However, the conventional Ni-based anode has low tolerance to sulfur-contamination, is vulnerable to deactivation by carbon build-up (coking from direct oxidation of hydrocarbon fuels, and suffers volume instability upon redox cycling. Among these limitations, the redox instability of the anode is particularly important and has been intensively studied since the SOFC anode may experience redox cycling during fuel cell operations even with the ideal pure hydrogen as the fuel. This review aims to highlight recent progresses on improving redox stability of the conventional Ni-based anode through microstructure optimization and exploration of alternative ceramic-based anode materials.

  18. Effective NiMn Nanoparticles-Functionalized Carbon Felt as an Effective Anode for Direct Urea Fuel Cells

    Directory of Open Access Journals (Sweden)

    Nasser A. M. Barakat

    2018-05-01

    Full Text Available The internal resistances of fuel cells strongly affect the generated power. Basically, in the fuel cell, the anode can be prepared by deposition of a film from the functional electrocatalyst on a proper gas diffusion layer. Accordingly, an interfacial resistance for the electron transport is created between the two layers. Electrocatalyst-functionalized gas diffusion layer (GDL can distinctly reduce the interfacial resistance between the catalyst layer and the GDL. In this study, NiMn nanoparticles-decorated carbon felt is introduced as functionalized GDL to be exploited as a ready-made anode in a direct urea fuel cell. The proposed treated GDL was prepared by calcination of nickel acetate/manganese acetate-loaded carbon felt under an argon atmosphere at 850 °C. The physiochemical characterizations confirmed complete reduction for the utilized precursors and deposition of pristine NiMn nanoparticles on the carbon felt fiber. In passive direct urea fuel cells, investigation the performance of the functionalized GDLs indicated that the composition of the metal nanoparticles has to be optimized as the GDL obtained from 40 wt % manganese acetate reveals the maximum generated power density; 36 mW/m2 at room temperature and 0.5 M urea solution. Moreover, the electrochemical measurements proved that low urea solution concentration is preferred as utilizing 0.5 M solution resulted into generating higher power compared to 1.0 and 2.0 M solution. Overall, this study opens a new avenue toward functionalization of the GDL as a novel strategy to overcome the interfacial resistance between the electrocatalyst and the GDL.

  19. Electrochemical performance of Si-multiwall carbon nanotube nanocomposite anode synthesized by thermal plasma

    Energy Technology Data Exchange (ETDEWEB)

    Na, Ye-Seul; Yoo, Hyeonseok; Kim, Tae-Hee; Choi, Jinsub; Lee, Wan In; Choi, Sooseok, E-mail: sooseok@jejunu.ac.kr; Park, Dong-Wha, E-mail: dwpark@inha.ac.kr

    2015-07-31

    Lithium-ion (Li-ion) batteries are widely used in electric devices and vehicles. Silicon is a promising material for the anode of Li-ion battery due to high theoretical specific capacity. However, it shows large volume changes during charge–discharge cycles leading to the pulverization of electrode. In order to improve such disadvantage, a multiwall carbon nanotube (MWCNT) has been used with silicon as composite material. In this work, Si-MWCNT nanocomposite was prepared in thermal plasma by attaching silicon nanoparticles to MWCNT column. Electrochemical tests for raw materials and synthesized nanocomposites were carried out. The discharge capacities of silicon, MWCNT, synthesized nanocomposites collected from a reaction tube, and a chamber were 4000, 310, 200, and 1447 mAh/g, respectively. - Highlights: • Si-Multiwall carbon nanotube nanocomposite was synthesized by thermal plasma. • The effect on the collection position of product after experiment was examined. • Cycle performance of electrodes was measured. • Product collected from chamber showed good electrochemical performance.

  20. Toward Small-Diameter Carbon Nanotubes Synthesized from Captured Carbon Dioxide: Critical Role of Catalyst Coarsening.

    Science.gov (United States)

    Douglas, Anna; Carter, Rachel; Li, Mengya; Pint, Cary L

    2018-05-23

    Small-diameter carbon nanotubes (CNTs) often require increased sophistication and control in synthesis processes, but exhibit improved physical properties and greater economic value over their larger-diameter counterparts. Here, we study mechanisms controlling the electrochemical synthesis of CNTs from the capture and conversion of ambient CO 2 in molten salts and leverage this understanding to achieve the smallest-diameter CNTs ever reported in the literature from sustainable electrochemical synthesis routes, including some few-walled CNTs. Here, Fe catalyst layers are deposited at different thicknesses onto stainless steel to produce cathodes, and atomic layer deposition of Al 2 O 3 is performed on Ni to produce a corrosion-resistant anode. Our findings indicate a correlation between the CNT diameter and Fe metal layer thickness following electrochemical catalyst reduction at the cathode-molten salt interface. Further, catalyst coarsening during long duration synthesis experiments leads to a 2× increase in average diameters from 3 to 60 min durations, with CNTs produced after 3 min exhibiting a tight diameter distribution centered near ∼10 nm. Energy consumption analysis for the conversion of CO 2 into CNTs demonstrates energy input costs much lower than the value of CNTs-a concept that strictly requires and motivates small-diameter CNTs-and is more favorable compared to other costly CO 2 conversion techniques that produce lower-value materials and products.

  1. Effect of Slotted Anode on Gas Bubble Behaviors in Aluminum Reduction Cell

    Science.gov (United States)

    Sun, Meijia; Li, Baokuan; Li, Linmin; Wang, Qiang; Peng, Jianping; Wang, Yaowu; Cheung, Sherman C. P.

    2017-12-01

    In the aluminum reduction cells, gas bubbles are generated at the bottom of the anode which eventually reduces the effective current contact area and the system efficiency. To encourage the removal of gas bubbles, slotted anode has been proposed and increasingly adopted by some industrial aluminum reduction cells. Nonetheless, the exact gas bubble removal mechanisms are yet to be fully understood. A three-dimensional (3D) transient, multiphase flow mathematical model coupled with magnetohydrodynamics has been developed to investigate the effect of slotted anode on the gas bubble movement. The Eulerian volume of fluid approach is applied to track the electrolyte (bath)-molten aluminum (metal) interface. Meanwhile, the Lagrangian discrete particle model is employed to handle the dynamics of gas bubbles with considerations of the buoyancy force, drag force, virtual mass force, and pressure gradient force. The gas bubble coalescence process is also taken into account based on the O'Rourke's algorithm. The two-way coupling between discrete bubbles and fluids is achieved by the inter-phase momentum exchange. Numerical predictions are validated against the anode current variation in an industrial test. Comparing the results using slotted anode with the traditional one, the time-averaged gas bubble removal rate increases from 36 to 63 pct; confirming that the slotted anode provides more escaping ways and shortens the trajectories for gas bubbles. Furthermore, the slotted anode also reduces gas bubble's residence time and the probability of coalescence. Moreover, the bubble layer thickness in aluminum cell with slotted anode is reduced about 3.5 mm (17.4 pct), so the resistance can be cut down for the sake of energy saving and the metal surface fluctuation amplitude is significantly reduced for the stable operation due to the slighter perturbation with smaller bubbles.

  2. Impact de la preparation des anodes crues et des conditions de cuisson sur la fissuration dans des anodes denses

    Science.gov (United States)

    Amrani, Salah

    La fabrication de l'aluminium est realisee dans une cellule d'electrolyse, et cette operation utilise des anodes en carbone. L'evaluation de la qualite de ces anodes reste indispensable avant leur utilisation. La presence des fissures dans les anodes provoque une perturbation du procede l'electrolyse et une diminution de sa performance. Ce projet a ete entrepris pour determiner l'impact des differents parametres de procedes de fabrication des anodes sur la fissuration des anodes denses. Ces parametres incluent ceux de la fabrication des anodes crues, des proprietes des matieres premieres et de la cuisson. Une recherche bibliographique a ete effectuee sur tous les aspects de la fissuration des anodes en carbone pour compiler les travaux anterieurs. Une methodologie detaillee a ete mise au point pour faciliter le deroulement des travaux et atteindre les objectifs vises. La majorite de ce document est reservee pour la discussion des resultats obtenus au laboratoire de l'UQAC et au niveau industriel. Concernant les etudes realisees a l'UQAC, une partie des travaux experimentaux est reservee a la recherche des differents mecanismes de fissuration dans les anodes denses utilisees dans l'industrie d'aluminium. L'approche etait d'abord basee sur la caracterisation qualitative du mecanisme de la fissuration en surface et en profondeur. Puis, une caracterisation quantitative a ete realisee pour la determination de la distribution de la largeur de la fissure sur toute sa longueur, ainsi que le pourcentage de sa surface par rapport a la surface totale de l'echantillon. Cette etude a ete realisee par le biais de la technique d'analyse d'image utilisee pour caracteriser la fissuration d'un echantillon d'anode cuite. L'analyse surfacique et en profondeur de cet echantillon a permis de voir clairement la formation des fissures sur une grande partie de la surface analysee. L'autre partie des travaux est basee sur la caracterisation des defauts dans des echantillons d'anodes crues

  3. A Rechargeable High-Temperature Molten Salt Iron-Oxygen Battery.

    Science.gov (United States)

    Peng, Cheng; Guan, Chengzhi; Lin, Jun; Zhang, Shiyu; Bao, Hongliang; Wang, Yu; Xiao, Guoping; Chen, George Zheng; Wang, Jian-Qiang

    2018-06-11

    The energy and power density of conventional batteries are far lower than their theoretical expectations, primarily because of slow reaction kinetics that are often observed under ambient conditions. Here we describe a low-cost and high-temperature rechargeable iron-oxygen battery containing a bi-phase electrolyte of molten carbonate and solid oxide. This new design merges the merits of a solid-oxide fuel cell and molten metal-air battery, offering significantly improved battery reaction kinetics and power capability without compromising the energy capacity. The as-fabricated battery prototype can be charged at high current density, and exhibits excellent stability and security in the highly charged state. It typically exhibits specific energy, specific power, energy density, and power density of 129.1 Wh kg -1 , 2.8 kW kg -1 , 388.1 Wh L -1 , and 21.0 kW L -1 , respectively, based on the mass and volume of the molten salt. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Corrosion resistance of metals and alloys in molten alkalies

    International Nuclear Information System (INIS)

    Zarubitskij, O.G.; Dmitruk, B.F.; Minets, L.A.

    1979-01-01

    Literature data on the corrosion of non-ferrous and noble metals, iron and steels in the molten alkalis and mixtures of their base are presented. It is shown that zirconium, niobium and tantalum are characterized by high corrosion stability in the molten NaOH. Additions of NaOH and KOH to the alkali chloride melts result in a 1000 time decrease of zirconium corrosion rate at 850 deg. The data testify to the characteristic passivating properties of OH - ions; Mo and W do not possess an ability to selfpassivation in hydroxide melts. Corrosion resistance of carbon and chromium-nickel steels in hydroxide melts depends considerably on the temperature, electrolyte composition and atmosphere over them. At the temperatures up to 600 deg C chromium-nickel steel is corrosion resistant in the molten alkali only in the inert atmosphere. Corrosion rate of chromium-nickel alloy is the lower the less chromium and the more nickel it contains. For the small installations the 4Kh18N25S2 and Kh23N28M3D3T steels can be recommended

  5. Improved Anode for a Direct Methanol Fuel Cell

    Science.gov (United States)

    Valdez, Thomas; Narayanan, Sekharipuram

    2005-01-01

    A modified chemical composition has been devised to improve the performance of the anode of a direct methanol fuel cell. The main feature of the modified composition is the incorporation of hydrous ruthenium oxide into the anode structure. This modification can reduce the internal electrical resistance of the cell and increase the degree of utilization of the anode catalyst. As a result, a higher anode current density can be sustained with a smaller amount of anode catalyst. These improvements can translate into a smaller fuel-cell system and higher efficiency of conversion. Some background information is helpful for understanding the benefit afforded by the addition of hydrous ruthenium oxide. The anode of a direct methanol fuel cell sustains the electro-oxidation of methanol to carbon dioxide in the reaction CH3OH + H2O--->CO2 + 6H(+) + 6e(-). An electrocatalyst is needed to enable this reaction to occur. The catalyst that offers the highest activity is an alloy of approximately equal numbers of atoms of the noble metals platinum and ruthenium. The anode is made of a composite material that includes high-surface-area Pt/Ru alloy particles and a proton-conducting ionomeric material. This composite is usually deposited onto a polymer-electrolyte (proton-conducting) membrane and onto an anode gas-diffusion/current-collector sheet that is subsequently bonded to the proton-conducting membrane by hot pressing. Heretofore, the areal density of noble-metal catalyst typically needed for high performance has been about 8 mg/cm2. However, not all of the catalyst has been utilized in the catalyzed electro-oxidation reaction. Increasing the degree of utilization of the catalyst would make it possible to improve the performance of the cell for a given catalyst loading and/or reduce the catalyst loading (thereby reducing the cost of the cell). The use of carbon and possibly other electronic conductors in the catalyst layer has been proposed for increasing the utilization of the

  6. Reduction reaction of chlorine gas in an Al-Cl2 chemical cell composed of molten chloride salts; Enkabutsu yoyuenkei Al-Cl2 kagaku denchi ni okeru enso gas no kangen hanno kyodo

    Energy Technology Data Exchange (ETDEWEB)

    Konda, S.; Sasaki, T.; Ishikawa, T. [Hokkaido University, Sapporo (Japan)

    1996-10-05

    The molten salt system electrochemical cycle was proposed to reproduce pure Al from scrap Al. The cycle is composed of production of rough AlCl3 by chlorination of scrap Al, refining of rough AlCl3 mainly by sublimation, and electrolytic reproduction of pure Al from refined AlCl3. In production of AlCl3, the Al-Cl2 molten salt system cell composed of anode dissolution reaction of Al and cathode reduction reaction of chlorine gas can generate electric power for the electrolytic reproduction. Chlorine gas can be recycled as anode product. Various experiments were carried out to improve molten salt system cells. In analysis of cell output, voltage drop from open circuit voltage was divided into that due to electrolytic bath resistance, and that due to reaction resistance. The electrolytic bath resistance could be determined from transient characteristics of voltage change just after cutoff of output current. The product of the obtained reaction resistance and a meniscus length was constant regardless of a meniscus length, and useful to predict scale-up cell performance. Output characteristics dependent on meniscus position were also obtained. 16 refs., 11 figs.

  7. Efficient 3D conducting networks built by graphene sheets and carbon nanoparticles for high-performance silicon anode.

    Science.gov (United States)

    Zhou, Xiaosi; Yin, Ya-Xia; Cao, An-Min; Wan, Li-Jun; Guo, Yu-Guo

    2012-05-01

    The utilization of silicon particles as anode materials for lithium-ion batteries is hindered by their low intrinsic electric conductivity and large volume changes during cycling. Here we report a novel Si nanoparticle-carbon nanoparticle/graphene composite, in which the addition of carbon nanoparticles can effectively alleviate the aggregation of Si nanoparticles by separating them from each other, and help graphene sheets build efficient 3D conducting networks for Si nanoparticles. Such Si-C/G composite shows much improved electrochemical properties in terms of specific capacity and cycling performance (ca. 1521 mA h g(-1) at 0.2 C after 200 cycles), as well as a favorable high-rate capability.

  8. Synthesis and superior anode performances of TiO2-carbon-rGO composites in lithium-ion batteries.

    Science.gov (United States)

    Ren, Yameng; Zhang, Juan; Liu, Yanyan; Li, Hongbian; Wei, Huijuan; Li, Baojun; Wang, Xiangyu

    2012-09-26

    In this article, TiO(2)-Carbon-rGO (GCT) three-component composite material has been constructed by anchoring TiO(2) nanoparticles (NPs) encapsulated in carbon shells onto reduced graphene oxide (rGO) sheets. The structure of GCT was characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), N(2) adsorption-desorption isotherms, and transmission electron microscopy (TEM). This material shows a superior retention as the anode materials in lithium ion battery with a specific discharge capacity of 188 mA h g(-1) in the initial cycle and 158 mA h g(-1) after 100 cycles.

  9. Experiment and numerical simulation on the performance of a kw-scale molten carbonate fuel cell stack

    Directory of Open Access Journals (Sweden)

    L. J. Yu

    2007-12-01

    Full Text Available A high-temperature molten carbonate fuel cell stack was studied experimentally and computationally. Experimental data for fuel cell temperature was obtained when the stack was running under given operational conditions. A 3-D CFD numerical model was set up and used to simulate the central fuel cell in the stack. It includes the mass, momentum and energy conservation equations, the ideal gas law and an empirical equation for cell voltage. The model was used to simulate the transient behavior of the fuel cell under the same operational conditions as those of the experiment. Simulation results show that the transient temperature and current and power densities reach their maximal values at the channel outlet. A comparison of the modeling results and the experimental data shows the good agreement.

  10. Core-shell Si/C nanospheres embedded in bubble sheet-like carbon film with enhanced performance as lithium ion battery anodes.

    Science.gov (United States)

    Li, Wenyue; Tang, Yongbing; Kang, Wenpei; Zhang, Zhenyu; Yang, Xia; Zhu, Yu; Zhang, Wenjun; Lee, Chun-Sing

    2015-03-18

    Due to its high theoretical capacity and low lithium insertion voltage plateau, silicon has been considered one of the most promising anodes for high energy and high power density lithium ion batteries (LIBs). However, its rapid capacity degradation, mainly caused by huge volume changes during lithium insertion/extraction processes, remains a significant challenge to its practical application. Engineering Si anodes with abundant free spaces and stabilizing them by incorporating carbon materials has been found to be effective to address the above problems. Using sodium chloride (NaCl) as a template, bubble sheet-like carbon film supported core-shell Si/C composites are prepared for the first time by a facile magnesium thermal reduction/glucose carbonization process. The capacity retention achieves up to 93.6% (about 1018 mAh g(-1)) after 200 cycles at 1 A g(-1). The good performance is attributed to synergistic effects of the conductive carbon film and the hollow structure of the core-shell nanospheres, which provide an ideal conductive matrix and buffer spaces for respectively electron transfer and Si expansion during lithiation process. This unique structure decreases the charge transfer resistance and suppresses the cracking/pulverization of Si, leading to the enhanced cycling performance of bubble sheet-like composite. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Molten salt synthesis of nitrogen and oxygen enriched hierarchically porous carbons derived from biomass via rapid microwave carbonization for high voltage supercapacitors

    Science.gov (United States)

    Cheng, Yinfeng; Li, Baoqiang; Huang, Yanjuan; Wang, Yaming; Chen, Junchen; Wei, Daqing; Feng, Yujie; Jia, Dechang; Zhou, Yu

    2018-05-01

    Nitrogen and oxygen enriched hierarchically porous carbons (NOHPCs) derived from biomass have been successfully prepared by rapid microwave carbonization coupled with molten salt synthesis method in only 4 min. ZnCl2 plays important roles as microwave absorber, chemical activation agent and porogen in this process. NOHPC-1:10 sample possesses the maximum specific surface area of 1899 m2 g-1 with a pore volume of 1.16 cm3 g-1 and mesopore ratio of 70%, as well as nitrogen content of 5.30 wt% and oxygen content of 14.12 wt%. When evaluated as an electrode in a three-electrode system with 6 M KOH electrolyte, the material exhibits a high specific capacitance of 276 F g-1 at 0.2 A g-1, with a good rate capability of 90.9% retention at 10 A g-1. More importantly, the symmetric supercapacitor based on NOHPC-1:10 in 1 M Na2SO4 electrolyte exhibits a high energy density of 13.9 Wh kg-1 at a power density of 120 W kg-1 in a wide voltage window of 0-1.6 V, an excellent cycling stability with 95% of capacitance retention after 10,000 cycles. Our strategy provides a facile and rapid way for the preparation of advanced carbon materials derived from biomass towards energy storage applications.

  12. Hierarchical three-dimensional porous SnS{sub 2}/carbon cloth anode for high-performance lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Chao, Junfeng, E-mail: chchjjff@163.com [College of Electronic Information and Electric Engineering, Anyang Institute of Technology, Anyang 455000 (China); Zhang, Xiutai [College of Electronic Information and Electric Engineering, Anyang Institute of Technology, Anyang 455000 (China); Xing, Shumin [College of Mathematics and Physics, Anyang Institute of Technology, Anyang 455000 (China); Fan, Qiufeng; Yang, Junping; Zhao, Luhua; Li, Xiang [College of Electronic Information and Electric Engineering, Anyang Institute of Technology, Anyang 455000 (China)

    2016-08-15

    Graphical abstract: Hierarchical 3D porous SnS{sub 2}/carbon cloth, good electrochemical performance. - Highlights: • Hierarchical 3D porous SnS{sub 2}/carbon cloth has been firstly synthesized. • The SnS{sub 2}/carbon clothes were good candidates for excellent lithium ion batteries. • The SnS{sub 2}/carbon cloth exhibits improved capacity compared to pure SnS{sub 2}. - Abstract: Hierarchical three-dimension (3D) porous SnS{sub 2}/carbon clothes were synthesized via a facile polyol refluxing process. The as-synthesized samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmet–Teller (BET) and UV–vis diffuse reflectance spectrometer (UV–vis DRS). The 3D porous SnS{sub 2}/carbon clothes-based lithium ion batteries exhibited high reversible capacity and good rate capability as anode materials. The good electrochemical performance for lithium ion storage could be attributed to the special nanostructure, leading to high-rate transportation of electrolyte ion and electrons throughout the electrode matrix.

  13. Effect of Anode Change on Heat Transfer and Magneto-hydrodynamic Flow in Aluminum Reduction Cell

    Science.gov (United States)

    Wang, Qiang; Li, Baokuan; Fafard, Mario

    2016-02-01

    In order to explore the impact of anode replacement on heat transfer and magneto-hydrodynamic flow in aluminum smelting cells, a transient three-dimensional coupled mathematical model has been developed. With a steady state magnetic field, an electrical potential approach was used to obtain electromagnetic fields. Joule heating and Lorentz force, which were the source terms in the energy and momentum equations, were updated at each iteration. The phase change of molten electrolyte (bath) was modeled by an enthalpy-based technique in which the mushy zone was treated as a porous medium with porosity equal to the liquid fraction. A reasonable agreement between the test data and simulated results was achieved. Under normal conditions, the bath at the middle of the cell is hotter, while becoming colder at the four corners. Due to the heat extracted from the bath, the temperature of the new cold anode increases over time. The temperature of the bath under the new cold anode therefore quickly drops, resulting in a decrease of the electrical conductivity. More Joule effect is created. In addition, the bath under the new cold anode gradually freezes and flows more slowly. The temperature of the new anode located at the middle of the cell rises faster because of the warmer bath. It is easier to eliminate the effect of anode change when it occurs in the middle of the cell.

  14. Advanced heat exchanger development for molten salts

    Energy Technology Data Exchange (ETDEWEB)

    Sabharwall, Piyush, E-mail: Piyush.Sabharwall@inl.gov [Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Clark, Denis; Glazoff, Michael [Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Zheng, Guiqiu; Sridharan, Kumar; Anderson, Mark [University of Wisconsin, Madison (United States)

    2014-12-15

    Highlights: • Hastelloy N and 242, shows corrosion resistance to molten salt at nominal operating temperatures. • Both diffusion welds and sheet material in Hastelloy N were corrosion tested in at 650, 700, and 850 °C for 200, 500, and 1000 h. • Thermal gradients and galvanic couples in the molten salts enhance corrosion rates. • Corrosion rates found were typically <10 mils per year. - Abstract: This study addresses present work concerned with advanced heat exchanger development for molten salt in nuclear and non-nuclear thermal systems. The molten salt systems discussed herein use alloys, such as Hastelloy N and 242, that show good corrosion resistance in molten salt at nominal operating temperatures up to 700 °C. These alloys were diffusion welded, and the corresponding information is presented. Test specimens were prepared for exposing diffusion welds to molten salt environments. Hastelloy N and 242 were found to be weldable by diffusion welding, with ultimate tensile strengths about 90% of base metal values. Both diffusion welds and sheet material in Hastelloy N were corrosion tested in 58 mol% KF and 42 mol% ZrF{sub 4} at 650, 700, and 850 °C for 200, 500, and 1000 h. Corrosion rates were similar between welded and nonwelded materials, typically <100 μm per year after 1000 h of corrosion tests. No catastrophic corrosion was observed in the diffusion welded regions. For materials of construction, nickel-based alloys and alloys with dense nickel coatings are effectively inert to corrosion in fluorides, but not so in chlorides. Hence, additional testing of selected alloys for resistance to intergranular corrosion is needed, as is a determination of corrosion rate as a function of the type of salt impurity and alloy composition, with respect to chromium and carbon, to better define the best conditions for corrosion resistance. Also presented is the division of the nuclear reactor and high-temperature components per American Society of Mechanical

  15. Fabrication of carbon microcapsules containing silicon nanoparticles-carbon nanotubes nanocomposite by sol-gel method for anode in lithium ion battery

    International Nuclear Information System (INIS)

    Bae, Joonwon

    2011-01-01

    Carbon microcapsules containing silicon nanoparticles (Si NPs)-carbon nanotubes (CNTs) nanocomposite (Si-CNT-C) have been fabricated by a surfactant mediated sol-gel method followed by a carbonization process. Silicon nanoparticles-carbon nanotubes (Si-CNT) nanohybrids were produced by a wet-type beadsmill method. To obtain Si-CNT nanocomposites with spherical morphologies, a silica precursor (tetraethylorthosilicate, TEOS) and polymer (PMMA) mixture was employed as a structure-directing medium. Thus the Si-CNT/Silica-Polymer microspheres were prepared by an acid catalyzed sol-gel method. Then a carbon precursor such as polypyrrole (PPy) was incorporated onto the surfaces of pre-existing Si-CNT/silica-polymer to generate Si-CNT/Silica-Polymer-PPy microspheres. Subsequent thermal treatment of the precursor followed by wet etching of silica produced Si-CNT-C microcapsules. The intermediate silica/polymer must disappear during the carbonization and etching process resulting in the formation of an internal free space. The carbon precursor polymer should transform to carbon shell to encapsulate remaining Si-CNT nanocomposites. Therefore, hollow carbon microcapsules containing Si-CNT nanocomposites could be obtained (Si-CNT-C). The successful fabrication was confirmed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). These final materials were employed for anode performance improvement in lithium ion battery. The cyclic performances of these Si-CNT-C microcapsules were measured with a lithium battery half cell tests. - Graphical Abstract: Carbon microcapsules containing silicon nanoparticles (Si NPs)-carbon nanotubes (CNTs) nanocomposite (Si-CNT-C) have been fabricated by a surfactant mediated sol-gel method. Highlights: → Polymeric microcapsules containing Si-CNT transformed to carbon microcapsules. → Accommodate volume changes of Si NPs during Li ion charge/discharge. → Sizes of microcapsules were controlled by experimental parameters.

  16. Electrochemical studies and analysis of 1–10 wt% UCl3 concentrations in molten LiCl–KCl eutectic

    International Nuclear Information System (INIS)

    Hoover, Robert O.; Shaltry, Michael R.; Martin, Sean; Sridharan, Kumar; Phongikaroon, Supathorn

    2014-01-01

    Three electrochemical methods – cyclic voltammetry (CV), chronopotentiometry (CP), and anodic stripping voltammetry (ASV) – were applied to solutions of up to 10 wt% UCl 3 in the molten LiCl–KCl eutectic salt at 500 °C to determine electrochemical properties and behaviors and to help provide a scientific basis for the development of an in situ electrochemical probe for determining the concentration of uranium in a used nuclear fuel electrorefiner. Diffusion coefficients of UCl 4 and UCl 3 were calculated to be (6.72 ± 0.360) × 10 −6 cm 2 /s and (1.04 ± 0.17) × 10 −5 cm 2 /s, respectively. Apparent standard reduction potentials were determined to be (−0.381 ± 0.013) V and (−1.502 ± 0.076) V vs. 5 mol% Ag/AgCl or (−1.448 ± 0.013) V and (−2.568 ± 0.076) V vs. Cl 2 /Cl − for the U(IV)/U(III) and U(III)/U redox couples, respectively. In comparing this data with supercooled thermodynamic data to determine activity coefficients, the thermodynamic database used was important with resulting activity coefficients ranging from 2.34 × 10 −3 to 1.08 × 10 −2 for UCl 4 and 4.94 × 10 −5 to 4.50 × 10 −4 for UCl 3 . Of anodic stripping voltammetry and cyclic voltammetry anodic or cathodic peaks, the CV cathodic peak height divided by square root of scan rate was shown to be the most reliable method of determining UCl 3 concentration in the molten salt

  17. Electrochemical Performances of Diamond Like Carbon Films for Pb(II) Detection in Tap Water Using Differential Pulse Anodic Stripping Voltammetry Technique

    Czech Academy of Sciences Publication Activity Database

    Sbartai, A.; Namour, F.; Barbier, F.; Krejčí, J.; Kučerová, R.; Krejčí, T.; Neděla, Vilém; Sobota, Jaroslav; Jaffrezic-Renault, N.

    2013-01-01

    Roč. 11, č. 8 (2013), s. 1524-1529 ISSN 1546-198X Institutional support: RVO:68081731 Keywords : Diamond Like Carbon DLC * Lead Detection * Differential Pulse Anodic Stripping * Voltammetry * Tap Water Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.558, year: 2013

  18. Encapsulated Vanadium-Based Hybrids in Amorphous N-Doped Carbon Matrix as Anode Materials for Lithium-Ion Batteries.

    Science.gov (United States)

    Long, Bei; Balogun, Muhammad-Sadeeq; Luo, Lei; Luo, Yang; Qiu, Weitao; Song, Shuqin; Zhang, Lei; Tong, Yexiang

    2017-11-01

    Recently, researchers have made significant advancement in employing transition metal compound hybrids as anode material for lithium-ion batteries and developing simple preparation of these hybrids. To this end, this study reports a facile and scalable method for fabricating a vanadium oxide-nitride composite encapsulated in amorphous carbon matrix by simply mixing ammonium metavanadate and melamine as anode materials for lithium-ion batteries. By tuning the annealing temperature of the mixture, different hybrids of vanadium oxide-nitride compounds are synthesized. The electrode material prepared at 700 °C, i.e., VM-700, exhibits excellent cyclic stability retaining 92% of its reversible capacity after 200 cycles at a current density of 0.5 A g -1 and attractive rate performance (220 mAh g -1 ) under the current density of up to 2 A g -1 . The outstanding electrochemical properties can be attributed to the synergistic effect from heterojunction form by the vanadium compound hybrids, the improved ability of the excellent conductive carbon for electron transfer, and restraining the expansion and aggregation of vanadium oxide-nitride in cycling. These interesting findings will provide a reference for the preparation of transition metal oxide and nitride composites as well. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Fabrication of ZnO Nanowires Arrays by Anodization and High-Vacuum Die Casting Technique, and Their Piezoelectric Properties

    Directory of Open Access Journals (Sweden)

    Chin-Guo Kuo

    2016-03-01

    Full Text Available In this investigation, anodic aluminum oxide (AAO with arrayed and regularly arranged nanopores is used as a template in the high-vacuum die casting of molten zinc metal (Zn into the nanopores. The proposed technique yields arrayed Zn nanowires with an aspect ratio of over 600. After annealing, arrayed zinc oxide (ZnO nanowires are obtained. Varying the anodizing time yields AAO templates with thicknesses of approximately 50 μm, 60 μm, and 70 μm that can be used in the fabrication of nanowires of three lengths with high aspect ratios. Experimental results reveal that a longer nanowire generates a greater measured piezoelectric current. The ZnO nanowires that are fabricated using an alumina template are anodized for 7 h and produce higher piezoelectric current of up to 69 pA.

  20. Pilot demonstration of cerium oxide coated anodes

    Energy Technology Data Exchange (ETDEWEB)

    Gregg, J.S.; Frederick, M.S.; Shingler, M.J.; Alcorn, T.R.

    1992-10-01

    Cu cermet anodes were tested for 213 to 614 hours with an in-situ deposited CEROX coating in a pilot cell operated by Reynolds Manufacturing Technology Laboratory. At high bath ratio ([approximately]1.5) and low current density (0.5 A/cm[sup 2]), a [ge]1 mm thick dense CEROX coating was deposited on the anodes. At lower bath ratios and higher current density, the CEROX coating was thinner and less dense, but no change in corrosion rate was noted. Regions of low current density on the anodes and sides adjacent to the carbon anode sometimes had thin or absent CEROX coatings. Problems with cracking and oxidation of the cermet substrates led to higher corrosion rates in a pilot cell than would be anticipated from lab scale results.

  1. Molten salt oxidation as an alternative to incineration

    International Nuclear Information System (INIS)

    Gray, L.W.; Adamson, M.G.; Cooper, J.F.; Farmer, J.C.; Upadhye, R.S.

    1992-03-01

    Molten Salt Oxidation was originally developed by Rockwell International as part of their coal gasification, and nuclear-and hazardous-waste treatment programs. Single-stage oxidation units employing molten carbonate salt mixtures were found to process up to one ton/day of common solid and liquid wastes (such as paper, rags, plastics, and solvents), and (in larger units) up to one ton/hour of coal. After the oxidation of coal with excess oxygen, coal ash residuals (alumina-silicates) were found adhering to the vessel walls above the liquid level. The phenomenon was not observed with coal gasification-i.e., under oxygen-deficient conditions. Lawrence Livermore National Laboratory (LLNL) is developing a two-stage/two-vessel approach as a possible means of extending the utility of the process to wastes which contain high concentrations of alumina-silicates in the form of soils or clays, or high concentrations of nitrates including low-level and transuranic wastes. The first stage operates under oxygen-deficient (''pyrolysis'') conditions; the second stage completes oxidation of the evolved gases. The process allows complete oxidation of the organic materials without an open flame. In addition, all acidic gases that would be generated in incinerators are directly metathesized via the molten Na 2 CO 3 to form stable salts (NaCl, Na 2 SO 4 etc.). Molten salt oxidation therefore avoids the corrosion problems associated with free HCl in incineration. The process is being developed to use pure O 2 feeds in lieu of air, in order to reduce offgas volume and retain the option of closed system operation. In addition, ash is wetted and retained in the melt of the first vessel which must be replaced (continuously or batch-wise). The LLNL Molten Salt unit is described together with the initial operating data

  2. Yolk-shell structured Sb@C anodes for high energy Na-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Song, Junhua; Yan, Pengfei; Luo, Langli; Qi, Xingguo; Rong, Xiaohui; Zheng, Jianming; Xiao, Biwei; Feng, Shuo; Wang, Chongmin; Hu, Yong-Sheng; Lin, Yuehe; Sprenkle, Vincent L.; Li, Xiaolin

    2017-10-01

    Despite great advances in sodium-ion battery developments, the search for high energy and stable anode materials remains a challenge. Alloy or conversion-typed anode materials are attractive candidates of high specific capacity and low voltage potential, yet their applications are hampered by the large volume expansion and hence poor electrochemical reversibility and fast capacity fade. Here, we use antimony (Sb) as an example to demonstrate the use of yolk-shell structured anodes for high energy Na-ion batteries. The Sb@C yolk-shell structure prepared by controlled reduction and selective removal of Sb2O3 from carbon coated Sb2O3 nanoparticles can accommodate the Sb swelling upon sodiation and improve the structural/electrical integrity against pulverization. It delivers a high specific capacity of ~554 mAh•g-1, good rate capability (315 mhA•g-1 at 10C rate) and long cyclability (92% capacity retention over 200 cycles). Full-cells of O3-Na0.9[Cu0.22Fe0.30Mn0.48]O2 cathodes and Sb@C-hard carbon composite anodes demonstrate a high specific energy of ~130 Wh•kg-1 (based on the total mass of cathode and anode) in the voltage range of 2.0-4.0 V, ~1.5 times energy of full-cells with similar design using hard carbon anodes.

  3. Detection and removal of molten salts from molten aluminum alloys

    Energy Technology Data Exchange (ETDEWEB)

    K. Butcher; D. Smith; C. L. Lin; L. Aubrey

    1999-08-02

    Molten salts are one source of inclusions and defects in aluminum ingots and cast shapes. A selective adsorption media was used to remove these inclusions and a device for detection of molten salts was tested. This set of experiments is described and the results are presented and analyzed.

  4. Aluminothermic Reduction-Molten Salt Electrolysis Using Inert Anode for Oxygen and Al-Base Alloy Extraction from Lunar Soil Simulant

    Science.gov (United States)

    Xie, Kaiyu; Shi, Zhongning; Xu, Junli; Hu, Xianwei; Gao, Bingliang; Wang, Zhaowen

    2017-10-01

    Aluminothermic reduction-electrolysis using an inert anode process is proposed to extract oxygen and metals from Minnesota Lunar Simulant-1 (MLS-1). Effective aluminothermic reduction between dissolved MLS-1 and dissolved metal aluminum was achieved in cryolite salt media. The product phases obtained by aluminothermic reduction at 980°C for 4 h were Al, Si, and Al5FeSi, while the chemical components were 79.71 mass% aluminum, 12.03 mass% silicon, 5.91 mass% iron, and 2.35 mass% titanium. The cryolite salt containing Al2O3 was subsequently electrolyzed with Fe0.58-Ni0.42 inert anode at 960°C for 4 h. Oxygen was evolved at the anode with an anodic current efficiency of 78.28%. The results demonstrate that this two-step process is remarkably feasible for the extraterrestrial extraction of oxygen and metals. This process will help expand the existing in situ resource utilization methods.

  5. Limitations of disordered carbons obtained from biomass as anodes for real lithium-ion batteries.

    Science.gov (United States)

    Caballero, Alvaro; Hernán, Lourdes; Morales, Julián

    2011-05-23

    Two disordered microporous carbons were obtained from two different types of biomass residues: olive and cherry stones. The former (OS) was activated physically under steam while the latter (CS) chemically with an aqueous solution of ZnCl(2). Their structural and textural properties were studied by X-ray diffraction, scanning electron microscopy, and N(2) adsorption/desorption. Although the samples possess similar textural properties (BET surface areas, micropore surfaces and volumes), the CS carbon is more disordered than the OS carbon. Their electrochemical response in half-cells (CS[OS]/Li) is good; the values are comparable to those obtained from mesocarbon microbeads commonly used in commercial lithium-ion batteries, which consist of highly graphitized carbon. However, cells featuring the OS or CS carbon as anode and LiMn(2)O(4) as cathode perform poorly. Electrochemical activation of the electrodes against lithium metal, a recommended procedure for boosting the electrochemical properties of real lithium-ion batteries, improves cell performance (particularly with OS) but is ultimately ineffective: the delivered average capacity of the activated cell made from OS was less than half its theoretical value. The high irreversible capacity, high polarization between the charge and discharge curves, combined with the presence of various functional groups and the high disorder of the studied carbons which may facilitate side reactions such as electrolyte decomposition, results in a degraded cell performance. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Mass-producible method for preparation of a carbon-coated graphite@plasma nano-silicon@carbon composite with enhanced performance as lithium ion battery anode

    International Nuclear Information System (INIS)

    Chen, Hedong; Wang, Zhoulu; Hou, Xianhua; Fu, Lijun; Wang, Shaofeng; Hu, Xiaoqiao; Qin, Haiqing; Wu, Yuping

    2017-01-01

    Carbon-coated core-shell structure artificial graphite@plasma nano-silicon@carbon (AG@PNSi@C) composite, applying as lithium ion battery anode material, has been prepared via spray drying method. The plasma nano-silicon (<100 nm), which contained amorphous silicon, was synthesized by radio frequency induction plasma system with the high temperatures processing capability and high quench rates. The artificial graphite in the composite acts as the core which supports the particle and provides electroconductivity, while PNSi attached on the surface of the core, enhances the specific capacity of the composite. The as prepared composite shows superior performance as anode in lithium-ion batteries, regarding to the initial Coulombic efficiency and cycle life. The initial Coulombic efficiency of AG@PNSi@C electrode is 81.0% with a discharge capacity of 553 mAh g −1 and a recharge capacity of 448 mAh g −1 . During cycling, AG@PNSi@C exhibits excellent performance with a very low capacity fading that the discharge capacity maintains 498.2 mAh g −1 and 449.4 mAh g −1 after 250 cycles and 500 cycles. AG@PNSi@C also shows enhanced resistance against high current density. Besides the remarkable electrochemical performances, the facile and mass-producible synthesis process makes the AG@PNSi@C composite very promising for its application in lithium-ion batteries.

  7. Sulfur Poisoning of Ni/stabilized-zirconia Anodes – Effect on Long-Term Durability

    DEFF Research Database (Denmark)

    Hauch, Anne; Hagen, Anke; Hjelm, Johan

    2013-01-01

    Sulfur impurities in carbon containing fuels for solid oxide fuel cells (SOFC), e.g. natural gas and biogas, can lead to significant losses in performance due to the sulfur sensitivity of Ni/YSZ SOFC anodes. Full cells having Ni/YSZ and Ni/ScYSZ anodes have been characterized during long-term gal...... to focus on the long-term effect over a few hundred of hours. This work describes and correlates the observed evolution of anode performance, over hundreds of hours, with sulfur poisoning with the different operating conditions.......Sulfur impurities in carbon containing fuels for solid oxide fuel cells (SOFC), e.g. natural gas and biogas, can lead to significant losses in performance due to the sulfur sensitivity of Ni/YSZ SOFC anodes. Full cells having Ni/YSZ and Ni/ScYSZ anodes have been characterized during long...

  8. Process development and exergy cost sensitivity analysis of a hybrid molten carbonate fuel cell power plant and carbon dioxide capturing process

    Science.gov (United States)

    Mehrpooya, Mehdi; Ansarinasab, Hojat; Moftakhari Sharifzadeh, Mohammad Mehdi; Rosen, Marc A.

    2017-10-01

    An integrated power plant with a net electrical power output of 3.71 × 105 kW is developed and investigated. The electrical efficiency of the process is found to be 60.1%. The process includes three main sub-systems: molten carbonate fuel cell system, heat recovery section and cryogenic carbon dioxide capturing process. Conventional and advanced exergoeconomic methods are used for analyzing the process. Advanced exergoeconomic analysis is a comprehensive evaluation tool which combines an exergetic approach with economic analysis procedures. With this method, investment and exergy destruction costs of the process components are divided into endogenous/exogenous and avoidable/unavoidable parts. Results of the conventional exergoeconomic analyses demonstrate that the combustion chamber has the largest exergy destruction rate (182 MW) and cost rate (13,100 /h). Also, the total process cost rate can be decreased by reducing the cost rate of the fuel cell and improving the efficiency of the combustion chamber and heat recovery steam generator. Based on the total avoidable endogenous cost rate, the priority for modification is the heat recovery steam generator, a compressor and a turbine of the power plant, in rank order. A sensitivity analysis is done to investigate the exergoeconomic factor parameters through changing the effective parameter variations.

  9. Molten material-containing vessel

    International Nuclear Information System (INIS)

    Akagawa, Katsuhiko

    1998-01-01

    The molten material-containing vessel of the present invention comprises a vessel main body having an entrance opened at the upper end, a lid for closing the entrance, an outer tube having an upper end disposed at the lower surface of the lid, extended downwardly and having an closed lower end and an inner tube disposed coaxially with the outer tube. When a molten material is charged from the entrance to the inside of the vessel main body of the molten material-containing vessel and the entrance is closed by the lid, the outer tube and the inner tube are buried in the molten material in the vessel main body, accordingly, a fluid having its temperature elevated by absorption of the heat of the molten material rises along the inner circumferential surface of the outer tube, abuts against the lower surface of the lid and cooled by exchanging heat with the lid and forms a circulating flow. Since the heat in the molten material is continuously absorbed by the fluid, transferred to the lid and released from the lid to the atmospheric air, heat releasing efficiency can be improved compared with conventional cases. (N.H.)

  10. Performance and stability of a liquid anode high-temperature metal-air battery

    Science.gov (United States)

    Otaegui, L.; Rodriguez-Martinez, L. M.; Wang, L.; Laresgoiti, A.; Tsukamoto, H.; Han, M. H.; Tsai, C.-L.; Laresgoiti, I.; López, C. M.; Rojo, T.

    2014-02-01

    A High-Temperature Metal-Air Battery (HTMAB) that operates based on a simple redox reaction between molten metal and atmospheric oxygen at 600-1000 °C is presented. This innovative HTMAB concept combines the technology of conventional metal-air batteries with that of solid oxide fuel cells to provide a high energy density system for many applications. Electrochemical reversibility is demonstrated with 95% coulomb efficiency. Cell sealing has been identified as a key issue in order to determine the end-of-charge voltage, enhance coulomb efficiency and ensure long term stability. In this work, molten Sn is selected as anode material. Low utilization of the stored material due to precipitation of the SnO2 on the electrochemically active area limits the expected capacity, which should theoretically approach 903 mAh g-1. Nevertheless, more than 1000 charge/discharge cycles are performed during more than 1000 h at 800 °C, showing highly promising results of stability, reversibility and cyclability.

  11. Neutron scattering on molten transition metals and on Fe-C melts

    International Nuclear Information System (INIS)

    Weber, M.

    1978-01-01

    In order to find out whether short-range order phenomena can be detected in iron-carbon melts, neutron scattering experiments were carried out in molten iron-carbon alloys. The method of isotope substitution, where the natural alloying iron was substituted by a 57 Fe-enriched isotope mixture, helped to increase the ratio between the scattering length of the carbon atoms and that of the iron atoms. The mean coherent scattering length for the isotope mixture which is required for further evaluation of the measurements, was determined in an experiment by measuring the limiting angle for total reflection of neutrons on evaporated films. From this determination of the scattering length, a value for the so far unknown scattering length of the 58 Fe isotope was obtained. The small angle scattering in corrected intensity curves of molten Fe-C alloys was investigated in detail. Scattering experiments in unalloyed Fe, Co, and Ni in the range of small scattering vectors proved that this small-angle scattering effect, which was observed here for the first time, is of magnetic origin. It is caused by short-range spin correlations fluctuating with space and time. [de

  12. Fabrication of flower-like tin/carbon composite microspheres as long-lasting anode materials for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Tae-Woo [Department of Chemical Engineering, College of Engineering, Hanyang University, Seoul, 133-791 (Korea, Republic of); Lim, Hyung-Seok [Department of WCU Engineering, College of Engineering, Hanyang University, Seoul, 133-791 (Korea, Republic of); Park, Seong-Jin [Department of Chemical Engineering, College of Engineering, Hanyang University, Seoul, 133-791 (Korea, Republic of); Sun, Yang-Kook [Department of WCU Engineering, College of Engineering, Hanyang University, Seoul, 133-791 (Korea, Republic of); Suh, Kyung-Do, E-mail: kdsuh@hanyang.ac.kr [Department of Chemical Engineering, College of Engineering, Hanyang University, Seoul, 133-791 (Korea, Republic of)

    2017-01-01

    In this work, we report the fabrication of the flower-like tin/carbon (Sn/C) composite microspheres using sulfonated semi-interpenetrating polystyrene (SPS) microspheres as a carbon precursor. The sulfonation degree of SPS has great effects on the resulting particle size, morphology, amount of introduced Sn, and the carbonization yield of the microspheres after heat treatment. The obtained Sn/C composite microspheres were characterized by scanning electron microscopy (SEM), focused-ion beam SEM, and X-ray diffraction. The flower-like Sn/C composite electrodes exhibited higher charge-discharge capacities than those of graphite as an anode material for a lithium ion battery. In addition, they show a long lasting cyclability, even through 400 cycles. - Highlights: • Tin nanocrystals are introduced in flower-like carbon spheres with many ripples. • Long lasting cyclability is exhibited at 1 C rate up to 400 cycles. • Tin content of composite spheres depends on chemical treatment of polymer microspheres.

  13. 2D Space-Confined Synthesis of Few-Layer MoS2 Anchored on Carbon Nanosheet for Lithium-Ion Battery Anode.

    Science.gov (United States)

    Zhou, Jingwen; Qin, Jian; Zhang, Xiang; Shi, Chunsheng; Liu, Enzuo; Li, Jiajun; Zhao, Naiqin; He, Chunnian

    2015-04-28

    A facile and scalable 2D spatial confinement strategy is developed for in situ synthesizing highly crystalline MoS2 nanosheets with few layers (≤5 layers) anchored on 3D porous carbon nanosheet networks (3D FL-MoS2@PCNNs) as lithium-ion battery anode. During the synthesis, 3D self-assembly of cubic NaCl particles is adopted to not only serve as a template to direct the growth of 3D porous carbon nanosheet networks, but also create a 2D-confined space to achieve the construction of few-layer MoS2 nanosheets robustly lain on the surface of carbon nanosheet walls. In the resulting 3D architecture, the intimate contact between the surfaces of MoS2 and carbon nanosheets can effectively avoid the aggregation and restacking of MoS2 as well as remarkably enhance the structural integrity of the electrode, while the conductive matrix of 3D porous carbon nanosheet networks can ensure fast transport of both electrons and ions in the whole electrode. As a result, this unique 3D architecture manifests an outstanding long-life cycling capability at high rates, namely, a specific capacity as large as 709 mAh g(-1) is delivered at 2 A g(-1) and maintains ∼95.2% even after 520 deep charge/discharge cycles. Apart from promising lithium-ion battery anode, this 3D FL-MoS2@PCNN composite also has immense potential for applications in other areas such as supercapacitor, catalysis, and sensors.

  14. Highly efficient solid-state synthesis of carbon-encapsulated ultrafine MoO{sub 2} nanocrystals as high rate lithium-ion battery anode

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Boyang, E-mail: byliu@shmtu.edu.cn [Shanghai Maritime University, College of Ocean Science and Engineering (China); Shao, Yingfeng, E-mail: shaoyf@lnm.imech.ac.cn [Chinese Academy of Sciences, State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics (China); Zhang, Yuliang, E-mail: ylzhang@shmtu.edu.cn; Zhang, Fuhua, E-mail: fhzhang@shmtu.edu.cn; Zhong, Ning, E-mail: ningzhong@shmtu.edu.cn [Shanghai Maritime University, College of Ocean Science and Engineering (China); Li, Wenge, E-mail: wgli@shmtu.edu.cn [Shanghai Maritime University, Merchant Marine College (China)

    2016-12-15

    A simple and highly efficient method is developed for the one-step in situ preparation of carbon-encapsulated MoO{sub 2} nanocrystals (MoO{sub 2}@C) with core-shell structure for high-performance lithium-ion battery anode. The synthesis is depending on the solid-state reaction of cyclopentadienylmolybdenum tricarbonyl dimer with ammonium persulfate in an autoclave at 200 °C for 30 min. The large amount of heat generated during the explosive reaction cleaves the cyclopentadiene ligands into small carbon fragments, which form carbon shell after oxidative dehydrogenation coating on the MoO{sub 2} nanocrystals, resulting in the formation of core-shell structure. The MoO{sub 2} nanocrystals have an equiaxial morphology with an ultrafine diameter of 2–8 nm, and the median size is 4.9 nm. Hundreds of MoO{sub 2} nanocrystals are encapsulated together by the worm-like carbon shell, which is amorphous and about 3–5 nm in thickness. The content of MoO{sub 2} nanocrystals in the nanocomposite is about 69.3 wt.%. The MoO{sub 2}@C anode shows stable cyclability and retains a high reversible capacity of 443 mAh g{sup −1} after 50 cycles at a current density of 3 A g{sup −1}, owing to the effective protection of carbon shell.

  15. Molten fluoride fuel salt chemistry

    International Nuclear Information System (INIS)

    Toth, L.M.; Del Cul, G.D.; Dai, S.; Metcalf, D.H.

    1995-01-01

    The chemistry of molten fluorides is traced from their development as fuels in the Molten Salt Reactor Experiment with important factors in their selection being discussed. Key chemical characteristics such as solubility, redox behavior, and chemical activity are explained as they relate to the behavior of molten fluoride fuel systems. Development requirements for fitting the current state of the chemistry to modern nuclear fuel system are described. It is concluded that while much is known about molten fluoride behavior which can be used effectively to reduce the amount of development required for future systems, some significant molten salt chemical questions must still be addressed. copyright American Institute of Physics 1995

  16. Symbiotic molten-salt systems coupled with accelerator molten-salt breeder (AMSB) or inertial-confined fusion hybrid molten-salt breeder (IHMSB) and their comparison

    International Nuclear Information System (INIS)

    Furukawa, K.

    1984-01-01

    Two types of breeder systems are proposed. One is the combined system of Accelerator Molten-Salt Breeder (AMSB) and Molten-Salt Converter Reactor (MSCR), and the other is the combined system of Inertial-confined Fusion Hybrid Molten-Salt Breeder (IHMSB) and modified MSCR. Both apply the molten-fluorides and have technically deep relations. AMSB would be much simpler and have already high technical feasibility. This will become economical the Th breeder system having a doubling time shorter than ten years and distributing any size of power stations MSCR. (orig.) [de

  17. Electrodeposition of Al-Mn alloy on AZ31B magnesium alloy in molten salts

    International Nuclear Information System (INIS)

    Zhang Jifu; Yan Chuanwei; Wang Fuhui

    2009-01-01

    The Al-Mn alloy coatings were electrodeposited on AZ31B Mg alloy in AlCl 3 -NaCl-KCl-MnCl 2 molten salts at 170 deg. C aiming to improve the corrosion resistance. However, in order to prevent AZ31B Mg alloy from corrosion during electrodeposition in molten salts and to ensure excellent adhesion of coatings to the substrate, AZ31B Mg alloy should be pre-plated with a thin zinc layer as intermediate layer. Then the microstructure, composition and phase constituents of the coatings were investigated by scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDX), and X-ray diffraction (XRD). It was indicated that, by adjusting the MnCl 2 content in the molten salts from 0.5 wt% to 2 wt%, the Mn content in the alloy coating was increased and the phase constituents were changed from f.c.c Al-Mn solid solution to amorphous phase. The corrosion resistance of the coatings was evaluated by potentiodynamic polarization measurements in 3.5% NaCl solution. It was confirmed that the Al-Mn alloy coatings exhibited good corrosion resistance with a chear passive region and significantly reduced corrosion current density at anodic potentiodynamic polarization. The corrosion resistance of the alloy coatings was also related with the microstructure and Mn content of the coatings.

  18. Electrolyte loss mechanism of molten carbonate fuel cells. 2.; Application to the cell with matrix electrolyte layer; Yoyu tansan`engata nenryo denchi ni okeru denkaishitsu loss kiko ni tsuite. 2.; Matrix gata denkaishitsuso wo yusuru denchi eno oyo

    Energy Technology Data Exchange (ETDEWEB)

    Sonai, A; Murata, K [Toshiba Research and Development Center, Kawasaki (Japan)

    1993-11-01

    A single cell of molten carbonate fuel cell using a matrix electrolyte layer fabricated by using the doctor blade process has been operated for several thousand hours, measured of electrolyte loss amount, and analyzed by using a new electrolyte loss mechanism. The result may be summarized as follows: according to a result of measuring the matrix layer pore distribution, the average pore size has increased little by little; pores with diameters greater than 2 {mu}m at which no electrolyte retention becomes possible remain at nearly constant ratio up to 1800 hours, but increased after 2500 hours; the pore capacity in ports with the largest electrolyte retaining diameter of 2 {mu}m or less showed slight decrease with time in the anode, and an initial decrease followed by flatness, and then a sharp decrease after 1800 hours in the matrix layer; the electrolyte loss measurement values have remained nearly constant for 25 hours to 1800 hours, but increased sharply thereafter; and the electrolyte loss in this single cell due to pore capacity decrease in pores as power generating parts with diameters smaller than 2 {mu}m was explained quantitatively by a new electrolyte loss mechanism. 11 refs., 6 figs.

  19. Effects of coal-derived trace species on performance of molten carbonate fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    1992-05-01

    The Carbonate Fuel Cell is a very promising option for highly efficient generation of electricity from many fuels. If coal-gas is to be used, the interactions of coal-derived impurities on various fuel cell components need to be understood. Thus the effects on Carbonate Fuel Cell performance due to ten different coal-derived contaminants viz., NH{sub 3}, H{sub 2}S, HC{ell}, H{sub 2}Se, AsH{sub 3}, Zn, Pb, Cd, Sn, and Hg, have been studied at Energy Research Corporation. Both experimental and theoretical evaluations were performed, which have led to mechanistic insights and initial estimation of qualitative tolerance levels for each species individually and in combination with other species. The focus of this study was to investigate possible coal-gas contaminant effects on the anode side of the Carbonate Fuel Cell, using both out-of-cell thermogravimetric analysis by isothermal TGA, and fuel cell testing in bench-scale cells. Separate experiments detailing performance decay in these cells with high levels of ammonia contamination (1 vol %) and with trace levels of Cd, Hg, and Sn, have indicated that, on the whole, these elements do not affect carbonate fuel cell performance. However, some performance decay may result when a number of the other six species are present, singly or simultaneously, as contaminants in fuel gas. In all cases, tolerance levels have been estimated for each of the 10 species and preliminary models have been developed for six of them. At this stage the models are limited to isothermal, benchscale (300 cm{sup 2} size) single cells. The information obtained is expected to assist in the development of coal-gas cleanup systems, while the contaminant performance effects data will provide useful basic information for modeling fuel cell endurance in conjunction with integrated gasifier/fuel-cell systems (IGFC).

  20. Molten carbonate fuel cells fed with biogas: combating H(2)S.

    Science.gov (United States)

    Ciccoli, R; Cigolotti, V; Lo Presti, R; Massi, E; McPhail, S J; Monteleone, G; Moreno, A; Naticchioni, V; Paoletti, C; Simonetti, E; Zaza, F

    2010-06-01

    The use of biomass and waste to produce alternative fuels, due to environmental and energy security reasons, is a high-quality solution especially when integrated with high efficiency fuel cell applications. In this article we look into the coupling of an anaerobic digestion process of organic residues to electrochemical conversion to electricity and heat through a molten carbonate fuel cell (MCFC). In particular the pathway of the exceedingly harmful compound hydrogen sulphide (H(2)S) in these phases is analysed. Hydrogen sulphide production in the biogas is strongly interrelated with methane and/or hydrogen yield, as well as with operating conditions like temperature and pH. When present in the produced biogas, this compound has multiple negative effects on the performance and durability of an MCFC. Therefore, there are important issues of integration to be solved. Three general approaches to solve the sulphur problem in the MCFC are possible. The first is to prevent the formation of hydrogen sulphide at the source: favouring conditions that inhibit its production during fermentation. Secondly, to identify the sulphur tolerance levels of the fuel cell components currently in use and develop sulphur-tolerant components that show long-term electrochemical performance and corrosion stability. The third approach is to remove the generated sulphur species to very low levels before the gas enters the fuel cell. Copyright 2010 Elsevier Ltd. All rights reserved.

  1. Application of molten salt oxidation for the minimization and recovery of plutonium-238 contaminated wastes

    International Nuclear Information System (INIS)

    Wishau, R.; Ramsey, K.B.; Montoya, A.

    1998-01-01

    This paper presents the technical and economic feasibility of molten salt oxidation technology as a volume reduction and recovery process for 238 Pu contaminated waste. Combustible low-level waste material contaminated with 238 Pu residue is destroyed by oxidation in a 900 C molten salt reaction vessel. The combustible waste is destroyed creating carbon dioxide and steam and a small amount of ash and insoluble 2328 Pu in the spent salt. The valuable 238 Pu is recycled using aqueous recovery techniques. Experimental test results for this technology indicate a plutonium recovery efficiency of 99%. Molten salt oxidation stabilizes the waste converting it to a non-combustible waste. Thus installation and use of molten salt oxidation technology will substantially reduce the volume of 238 Pu contaminated waste. Cost-effectiveness evaluations of molten salt oxidation indicate a significant cost savings when compared to the present plans to package, or re-package, certify and transport these wastes to the Waste Isolation Pilot Plant for permanent disposal. Clear and distinct cost advantages exist for MSO when the monetary value of the recovered 238 Pu is considered

  2. Facile synthesis and lithium storage properties of a porous NiSi2/Si/carbon composite anode material for lithium-ion batteries.

    Science.gov (United States)

    Jia, Haiping; Stock, Christoph; Kloepsch, Richard; He, Xin; Badillo, Juan Pablo; Fromm, Olga; Vortmann, Britta; Winter, Martin; Placke, Tobias

    2015-01-28

    In this work, a novel, porous structured NiSi2/Si composite material with a core-shell morphology was successfully prepared using a facile ball-milling method. Furthermore, the chemical vapor deposition (CVD) method is deployed to coat the NiSi2/Si phase with a thin carbon layer to further enhance the surface electronic conductivity and to mechanically stabilize the whole composite structure. The morphology and porosity of the composite material was evaluated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and nitrogen adsorption measurements (BJH analysis). The as-prepared composite material consists of NiSi2, silicon, and carbon phases, in which the NiSi2 phase is embedded in a silicon matrix having homogeneously distributed pores, while the surface of this composite is coated with a carbon layer. The electrochemical characterization shows that the porous and core-shell structure of the composite anode material can effectively absorb and buffer the immense volume changes of silicon during the lithiation/delithiation process. The obtained NiSi2/Si/carbon composite anode material displays an outstanding electrochemical performance, which gives a stable capacity of 1272 mAh g(-1) for 200 cycles at a charge/discharge rate of 1C and a good rate capability with a reversible capacity of 740 mAh g(-1) at a rate of 5C.

  3. Vertically aligned carbon nanotubes as anode and air-cathode in single chamber microbial fuel cells

    Science.gov (United States)

    Amade, R.; Moreno, H. A.; Hussain, S.; Vila-Costa, M.; Bertran, E.

    2016-10-01

    Electrode optimization in microbial fuel cells is a key issue to improve the power output and cell performance. Vertically aligned carbon nanotubes (VACNTs) grown on low cost stainless-steel mesh present an attractive approach to increase the cell performance while avoiding the use of expensive Pt-based materials. In comparison with non-aligned carbon nanotubes (NACNTs), VACNTs increase the oxygen reduction reaction taking place at the cathode by a factor of two. In addition, vertical alignment also increases the power density up to 2.5 times with respect to NACNTs. VACNTs grown at the anode can further improve the cell performance by increasing the electrode surface area and thus the electron transfer between bacteria and the electrode. The maximum power density obtained using VACNTs was 14 mW/m2 and 160 mV output voltage.

  4. S/N dual-doped carbon nanosheets decorated with Co x O y nanoparticles as high-performance anodes for lithium-ion batteries

    Science.gov (United States)

    Wang, XiaoFei; Zhu, Yong; Zhu, Sheng; Fan, JinChen; Xu, QunJie; Min, YuLin

    2018-03-01

    In this work, we have successfully synthesized the S/N dual-doped carbon nanosheets which are strongly coupled with Co x O y nanoparticles (SNCC) by calcinating cobalt/dithizone complex precursor following KOH activation. The SNCC as anode shows the wonderful charge capacity of 1200 mAh g-1 after 400th cycles at 1000 mA g-1 for Li-ion storage. The superior electrochemical properties illustrate that the SNCC can be a candidate for high-performance anode material of lithium-ion batteries (LIBs) because of the facile preparation method and excellent performance. Significantly, we also discuss the mechanism for the SNCC from the strong synergistic effect perspective.

  5. High performance ceramic carbon electrode-based anodes for use in the Cu-Cl thermochemical cycle for hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Ranganathan, Santhanam; Easton, E. Bradley [Faculty of Science, University of Ontario Institute of Technology, 2000 Simcoe Street North, Oshawa, Ontario L1H 7K4 (Canada)

    2010-02-15

    A high performance ceramic carbon electrode (CCE) was fabricated by the sol-gel method to study the CuCl electrolysis in Cu-Cl thermochemical cycle. The electrochemical behavior and stability of the CCE was investigated by polarization experiments at different concentrations of CuCl/HCl system. The CCE displayed excellent anodic performance and vastly outperformed the bare carbon fiber paper (CFP) even at high concentrations of CuCl (0.5 M) and HCl (6 M), which is explained in terms of increased active area and enhanced anion transport properties. Further enhancement of activity was achieved by coating the CCE layer onto both sides of the CFP substrate. (author)

  6. Aerosol assisted synthesis of hierarchical tin–carbon composites and their application as lithium battery anode materials

    KAUST Repository

    Guo, Juchen

    2013-01-01

    We report a method for synthesizing hierarchically structured tin-carbon (Sn-C) composites via aerosol spray pyrolysis. In this method, an aqueous precursor solution containing tin(ii) chloride and sucrose is atomized, and the resultant aerosol droplets carried by an inert gas are pyrolyzed in a high-temperature tubular furnace. Owing to the unique combination of high reaction temperature and short reaction time, this method is able to achieve a hetero-structure in which small Sn particles (15 nm) are uniformly embedded in a secondary carbon particle. This procedure allows the size and size distribution of the primary Sn particles to be tuned, as well as control over the size of the secondary carbon particles by addition of polymeric surfactant in the precursor solution. When evaluated as anode materials for lithium-ion batteries, the resultant Sn-C composites demonstrate attractive electrochemical performance in terms of overall capacity, electrochemical stability, and coulombic efficiency. © 2013 The Royal Society of Chemistry.

  7. Superior performance of nanoscaled Fe3O4 as anode material promoted by mosaicking into porous carbon framework

    Science.gov (United States)

    Wan, Wang; Wang, Chao; Zhang, Weidong; Chen, Jitao; Zhou, Henghui; Zhang, Xinxiang

    2014-01-01

    A nanoscale Fe3O4/porous carbon-multiwalled carbon nanotubes (MWCNTs) composite is synthesized through a simple hard-template method by using Fe2O3 nanoparticles as the precursor and SiO2 nanoparticles as the template. The composite shows good cycle performance (941 mAh g-1 for the first cycle at 0.1 C, with 106% capacity retention at the 80th cycle) and high rate capability (71% capacity retained at 5 C rate). Its excellent electrical properties can be attributed to the porous carbon framework structure, which is composed of carbon and MWCNTs. In this composite, the porous structure provides space for the change in Fe3O4 volume during cycling and shortens the lithium ion diffusion distance, the MWCNTs increase the electron conductivity, and the carbon coating reduces the risk of side reactions. The results provide clear evidences for the utility of porous carbon framework to improve the electrochemical performances of nanosized transition-metal oxides as anode materials for lithium-ion batteries.

  8. Sn/MWCNT Nanocomposites Fabricated by Ultrasonic Dispersion of Ni-Coated MWCNTs in Molten Tin

    Science.gov (United States)

    Billah, Md Muktadir; Chen, Quanfang

    2018-04-01

    Carbon nanotubes (CNTs) are regarded as a desirable filler to develop advanced composites including advanced solders due to their exceptional mechanical properties. However, some issues remain unsolved for metallic composites owing to "wetting" and nonuniform dispersion of CNTs. In this study, electroless nickel coating onto CNTs was used to overcome these issues. Multiwalled carbon nanotubes (MWCNTs) were used for this study, and Ni-coated MWCNTs were dispersed in molten Sn assisted by sonication and compared with MWCNTs without Ni coating. Adding 3 wt.% Ni-coated MWCNTs, which corresponds to 0.6 wt.% pure CNTs, resulted in an increase in tensile strength by 95% and hardness by 123%. Nickel coating also prevented separation of the CNTs from the molten metal due to buoyancy effects, leading to more uniform dispersion.

  9. The anodic dissolution of SIMFUEL (UO{sub 2}) in slightly alkaline sodium carbonate/bicarbonate solutions

    Energy Technology Data Exchange (ETDEWEB)

    Keech, P.G.; Goldik, J.S.; Qin, Z. [Department of Chemistry, University of Western Ontario, 1151 Richmond St, London ON, N6A 5B7 (Canada); Shoesmith, D.W., E-mail: dwshoesm@uwo.ca [Department of Chemistry, University of Western Ontario, 1151 Richmond St, London ON, N6A 5B7 (Canada)

    2011-09-30

    The corrosion of nuclear fuel under waste disposal conditions is likely to be influenced by the bicarbonate/carbonate content of the groundwater since it increases the solubility of the U{sup VI} corrosion product, [UO{sub 2}]{sup 2+}. As one of the half reactions involved in the corrosion process, the anodic dissolution of SIMFUEL (UO{sub 2}) has been studied in bicarbonate/carbonate solutions (pH 9.8) using voltammetric and potentiostatic techniques and electrochemical impedance spectroscopy. The reaction proceeds by two consecutive one electron transfer reactions (U{sup IV} {yields} U{sup V} {yields} U{sup VI}). At low potentials ({<=}250 mV (vs. SCE) the rate of the first electron transfer reaction is rate determining irrespective of the total carbonate concentration. At potentials >250 mV (vs. SCE) the formation of a U{sup VI}O{sub 2}CO{sub 3} surface layer begins to inhibit the dissolution rate and the current becomes independent of potential indicating rate control by the chemical dissolution of this layer.

  10. Low cost fuel cell diffusion layer configured for optimized anode water management

    Science.gov (United States)

    Owejan, Jon P; Nicotera, Paul D; Mench, Matthew M; Evans, Robert E

    2013-08-27

    A fuel cell comprises a cathode gas diffusion layer, a cathode catalyst layer, an anode gas diffusion layer, an anode catalyst layer and an electrolyte. The diffusion resistance of the anode gas diffusion layer when operated with anode fuel is higher than the diffusion resistance of the cathode gas diffusion layer. The anode gas diffusion layer may comprise filler particles having in-plane platelet geometries and be made of lower cost materials and manufacturing processes than currently available commercial carbon fiber substrates. The diffusion resistance difference between the anode gas diffusion layer and the cathode gas diffusion layer may allow for passive water balance control.

  11. Direct reduction of uranium dioxide and few other metal oxides to corresponding metals by high temperature molten salt electrolysis

    International Nuclear Information System (INIS)

    Mohandas, K.S.

    2017-01-01

    Molten salt based electro-reduction processes, capable of directly converting solid metal oxides to metals with minimum intermediate steps, are being studied worldwide. Production of metals apart, the process assumes importance in nuclear technology in the context of pyrochemical reprocessing of spent oxide fuels, for it serves as an intermediate step to convert spent oxide fuel to a metal alloy, which in turn can be processed by molten salt electro-refining method to gain the actinides present in it. In the context of future metal fuel fast reactor programme, the electrochemical process was studied for conversion of solid UO_2 to U metal in LiCl-1wt.% Li_2O melt at 650 °C with platinum anode at the Metal Processing Studies Section, PMPD, IGCAR. A brief overview of the work is presented in the paper

  12. Growth of SnO2 Nanoflowers on N-doped Carbon Nanofibers as Anode for Li- and Na-ion Batteries

    Science.gov (United States)

    Liang, Jiaojiao; Yuan, Chaochun; Li, Huanhuan; Fan, Kai; Wei, Zengxi; Sun, Hanqi; Ma, Jianmin

    2018-06-01

    It is urgent to solve the problems of the dramatic volume expansion and pulverization of SnO2 anodes during cycling process in battery systems. To address this issue, we design a hybrid structure of N-doped carbon fibers@SnO2 nanoflowers (NC@SnO2) to overcome it in this work. The hybrid NC@SnO2 is synthesized through the hydrothermal growth of SnO2 nanoflowers on the surface of N-doped carbon fibers obtained by electrospinning. The NC is introduced not only to provide a support framework in guiding the growth of the SnO2 nanoflowers and prevent the flower-like structures from agglomeration, but also serve as a conductive network to accelerate electronic transmission along one-dimensional structure effectively. When the hybrid NC@SnO2 was served as anode, it exhibits a high discharge capacity of 750 mAh g-1 at 1 A g-1 after 100 cycles in Li-ion battery and 270 mAh g-1 at 100 mA g-1 for 100 cycles in Na-ion battery, respectively.[Figure not available: see fulltext.

  13. Molten carbonate fuel cell system

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Yasuhiko; Kinoshita, Mamoru; Murakami, Shuzo; Furukawa, Nobuhiro

    1987-09-26

    Reformed gas or coal gasification gas, etc. is used as the fuel gas for fused carbonate fuel cells, however sulfuric compounds are contained in these gases and even after these gases have been treated beforehand through a desulfurizer, a trace quantity of H/sub 2/S is sent to a fuel electrode. Sulfur oxide which is formed at the time of burning and oxidating the exhaust gas from the fuel electrode is supplied together with the air to an oxygen electrode and becomes sulfate after substituting carbonate, which is the electrolyte of the electrode, causing deterioration of the cell characteristics and durability. With regard to a system that hydrogen rich gas which was reformed from the raw fuel is supplied to a fuel electrode, and its exhaust gas is oxidated through a burner to form carbon dioxide which is supplied together with the air to an oxygen electrode, this invention proposes the prevention of the aforementioned defects by providing at the down stream of the above burner a remover to trap with fused carbonate such sulfur compounds as SO/sub 2/ and SO/sub 3/ in the gas after being oxidated as above. (3 figs)

  14. Fabrication of porous anodic alumina using normal anodization and pulse anodization

    Science.gov (United States)

    Chin, I. K.; Yam, F. K.; Hassan, Z.

    2015-05-01

    This article reports on the fabrication of porous anodic alumina (PAA) by two-step anodizing the low purity commercial aluminum sheets at room temperature. Different variations of the second-step anodization were conducted: normal anodization (NA) with direct current potential difference; pulse anodization (PA) alternate between potential differences of 10 V and 0 V; hybrid pulse anodization (HPA) alternate between potential differences of 10 V and -2 V. The method influenced the film homogeneity of the PAA and the most homogeneous structure was obtained via PA. The morphological properties are further elucidated using measured current-transient profiles. The absent of current rise profile in PA indicates the anodization temperature and dissolution of the PAA structure were greatly reduced by alternating potential differences.

  15. Observation of the molten metal behaviors during the laser cutting of thick steel specimens using attenuated process images

    International Nuclear Information System (INIS)

    Tamura, Koji; Yamagishi, Ryuichiro

    2017-01-01

    Molten metal behaviors during the laser cutting of carbon steel and stainless steel specimens up to 300 mm in thickness were observed to dismantle large steel objects for the nuclear decommissioning, where attenuated process images from both steels were observed for detailed process analysis. Circular and rod-like molten metal structures were observed at the laser irradiated region depending on the assist gas flow conditions. Molten metal blow-off and flow processes were observed as cutting processes. The observations were explained by the aerodynamic interaction of the melted surface layer. The method is useful for the detailed observation of the molten metal behaviors, and the results are informative to understand and optimize the laser cutting process of very thick steel specimens. (author)

  16. Partial structures in molten AgBr

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, Hiroki [Department of Condensed Matter Chemistry and Physics, Faculty of Sciences, Kyushu University, 4-2-1 Ropponmatsu, Chuo-ku, Fukuoka 810-8560 (Japan)], E-mail: ueno@gemini.rc.kyushu-u.ac.jp; Tahara, Shuta [Faculty of Pharmacy, Niigata University of Pharmacy and Applied Life Science, Higashijima, Akiha-ku, Niigata 956-8603 (Japan); Kawakita, Yukinobu [Department of Physics, Faculty of Sciences, Kyushu University, 4-2-1 Ropponmatsu, Chuo-ku, Fukuoka 810-8560 (Japan); Kohara, Shinji [Research and Utilization Division, Japan Synchrotron Radiation Research Institute (JASRI, SPring-8), 1-1-1 Koto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Takeda, Shin' ichi [Department of Physics, Faculty of Sciences, Kyushu University, 4-2-1 Ropponmatsu, Chuo-ku, Fukuoka 810-8560 (Japan)

    2009-02-21

    The structure of molten AgBr has been studied by means of neutron and X-ray diffractions with the aid of structural modeling. It is confirmed that the Ag-Ag correlation has a small but well-defined first peak in the partial pair distribution function whose tail penetrates into the Ag-Br nearest neighbor distribution. This feature on the Ag-Ag correlation is intermediate between that of molten AgCl (non-superionic melt) and that of molten AgI (superionic melt). The analysis of Br-Ag-Br bond angle reveals that molten AgBr preserves a rocksalt type local ordering in the solid phase, suggesting that molten AgBr is clarified as non-superionic melt like molten AgCl.

  17. Electrolytic recovery of calcium from molten CaO-CaCl2 salt-mix

    International Nuclear Information System (INIS)

    Mishra, B.; Olson, D.L.

    1993-01-01

    Calciothermic reduction of plutonium oxide is an industrial process for producing plutonium metal. The process is carried out in a molten calcium chloride medium which has a significantly high solubility for calcium oxide. However, the CaO-CaCl 2 salt-mix is radioactively contaminated and can not be discarded as such. Fused salt electrolysis of a simulated mix has been carried out using graphite anode and steel cathode to produce calcium. The dissolved calcium in CaCl 2 salt can be used insitu to reduce plutonium oxide. The primary difficulty in obtaining a cathodic calcium deposit was the use of graphite anose which indirectly controls all the back-reactions in the cell through which the deposited calcium is lost. A porous ceramic sheath has been used to essentially keep the anodic and cathodic products separate. The porosity of the sheath has been optimized by measuring its diffusion coefficient as a function of temperature. The influence of a porous sheath on the cell potential has been also analyzed

  18. Organic anodes and sulfur/selenium cathodes for advanced Li and Na batteries

    Science.gov (United States)

    Luo, Chao

    To address energy crisis and environmental pollution induced by fossil fuels, there is an urgent demand to develop sustainable, renewable, environmental benign, low cost and high capacity energy storage devices to power electric vehicles and enhance clean energy approaches such as solar energy, wind energy and hydroenergy. However, the commercial Li-ion batteries cannot satisfy the critical requirements for next generation rechargeable batteries. The commercial electrode materials (graphite anode and LiCoO 2 cathode) are unsustainable, unrenewable and environmental harmful. Organic materials derived from biomasses are promising candidates for next generation rechargeable battery anodes due to their sustainability, renewability, environmental benignity and low cost. Driven by the high potential of organic materials for next generation batteries, I initiated a new research direction on exploring advanced organic compounds for Li-ion and Na-ion battery anodes. In my work, I employed croconic acid disodium salt and 2,5-Dihydroxy-1,4-benzoquinone disodium salt as models to investigate the effects of size and carbon coating on electrochemical performance for Li-ion and Na-ion batteries. The results demonstrate that the minimization of organic particle size into nano-scale and wrapping organic materials with graphene oxide can remarkably enhance the rate capability and cycling stability of organic anodes in both Li-ion and Na-ion batteries. To match with organic anodes, high capacity sulfur and selenium cathodes were also investigated. However, sulfur and selenium cathodes suffer from low electrical conductivity and shuttle reaction, which result in capacity fading and poor lifetime. To circumvent the drawbacks of sulfur and selenium, carbon matrixes such as mesoporous carbon, carbonized polyacrylonitrile and carbonized perylene-3, 4, 9, 10-tetracarboxylic dianhydride are employed to encapsulate sulfur, selenium and selenium sulfide. The resulting composites exhibit

  19. Molten Salt-Carbon Nanotube Thermal Energy Storage for Concentrating Solar Power Systems Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Michael Schuller; Frank Little; Darren Malik; Matt Betts; Qian Shao; Jun Luo; Wan Zhong; Sandhya Shankar; Ashwin Padmanaban

    2012-03-30

    We demonstrated that adding nanoparticles to a molten salt would increase its utility as a thermal energy storage medium for a concentrating solar power system. Specifically, we demonstrated that we could increase the specific heat of nitrate and carbonate salts containing 1% or less of alumina nanoparticles. We fabricated the composite materials using both evaporative and air drying methods. We tested several thermophysical properties of the composite materials, including the specific heat, thermal conductivity, latent heat, and melting point. We also assessed the stability of the composite material with repeated thermal cycling and the effects of adding the nanoparticles on the corrosion of stainless steel by the composite salt. Our results indicate that stable, repeatable 25-50% improvements in specific heat are possible for these materials. We found that using these composite salts as the thermal energy storage material for a concentrating solar thermal power system can reduce the levelized cost of electricity by 10-20%. We conclude that these materials are worth further development and inclusion in future concentrating solar power systems.

  20. Enabling fast electron transfer through both bacterial outer-membrane redox centers and endogenous electron mediators by polyaniline hybridized large-mesoporous carbon anode for high-performance microbial fuel cells

    International Nuclear Information System (INIS)

    Zou, Long; Qiao, Yan; Zhong, Canyu; Li, Chang Ming

    2017-01-01

    Both physical structure and chemical property of an electrode play critical roles in extracellular electron transfer from microbes to electrodes in microbial fuel cells (MFCs). Herein a novel polyaniline hybridized large mesoporous carbon (PANI-LMC) anode is fabricated from natural biomass by nanostructured CaCO 3 template-assisted carbonization followed by in situ chemical polymerizing PANI to enable fast extracellular electron transfer, in which the LMC with rich disorder-interconnected large mesopores (∼20−50 nm) and large surface area facilitates a fast mediated electron transfer through electron mediators, while the decorated PANI on LMC surface enables the direct electron transfer via bacterial outer-membrane redox centers. Owing to the unique synergistic effect from both excellent electron transfer paths, the PANI-LMC hybrid anode harvests high power electricity with a maximum output power density of 1280 mW m −2 in Shewanella putrefaciens CN32 MFCs, 10-fold higher than that of conventional carbon cloth. The findings from this work suggest a new insight on design of high-efficient anode according to the multiple and flexible electrochemical process for practical MFC applications.

  1. Thorium valency in molten alkali halides in equilibrium with metallic thorium

    International Nuclear Information System (INIS)

    Smirnov, M.V.; Kudyakov, V.Ya.

    1983-01-01

    Metallic thorium is shown to corrode in molten alkali halides even in the absence of external oxidizing agents, alkali cations acting as oxidizing agents. Its corrosion rate grows in the series of alkali chlorides from LiCl to CsCl at constant temperature. Substituting halide anions for one another exerts a smaller influence, the rate rising slightly in going from chlorides to bromides and iodides, having the same alkali cations. Thorium valency is determined coulometrically, the metal being dissolved anodically in molten alkali halides and their mixtures. In fluoride melts it is equal to 4 but in chloride, bromide and iodide ones, as a rule, it has non-integral values between 4 and 2 which diminish as the temperature is raised, as the thorium concentration is lowered, as the radii of alkali cations decrease and those of halide anions increase. The emf of cells Th/N ThHlsub(n) + (1-N) MHl/MHl/C, Hlsub(2(g)) where Hl is Cl, Br or I, M is Li, Na, K, Cs or Na + K, and N < 0.05, is measured as a function of concentration at several temperatures. Expressions are obtained for its concentration dependence. The emf grows in the series of alkali chlorides from LiCl to CsCl, other conditions being equal. (author)

  2. Electrochemical performance of BaSnO3 anode material for lithium-ion battery prepared by molten salt method

    CSIR Research Space (South Africa)

    Nithyadharseni, P

    2016-01-01

    Full Text Available Perovskite-like structure BaSnO(sub3) ceramic oxide has been prepared by low temperature molten salt method using KOH as a flux and Ba(OH)(sub2) and BaCl(sub2) as precursors. The as-prepared compounds were characterized by various techniques...

  3. Synthesis of SnO2 pillared carbon using long chain alkylamine grafted graphene oxide: an efficient anode material for lithium ion batteries.

    Science.gov (United States)

    Reddy, M Jeevan Kumar; Ryu, Sung Hun; Shanmugharaj, A M

    2016-01-07

    With the objective of developing new advanced composite materials that can be used as anodes for lithium ion batteries (LIBs), herein we describe the synthesis of SnO2 pillared carbon using various alkylamine (hexylamine; dodecylamine and octadecylamine) grafted graphene oxides and butyl trichlorotin precursors followed by its calcination at 500 °C for 2 h. While the grafted alkylamine induces crystalline growth of SnO2 pillars, thermal annealing of alkylamine grafted graphene oxide results in the formation of amorphous carbon coated graphene. Field emission scanning electron microscopy (FE-SEM) results reveal the successful formation of SnO2 pillared carbon on the graphene surface. X-ray diffraction (XRD), transmission electron microscopy (TEM) and Raman spectroscopy characterization corroborates the formation of rutile SnO2 crystals on the graphene surface. A significant rise in the BET surface area is observed for SnO2 pillared carbon, when compared to pristine GO. Electrochemical characterization studies of SnO2 pillared carbon based anode materials showed an enhanced lithium storage capacity and fine cyclic performance in comparison with pristine GO. The initial specific capacities of SnO2 pillared carbon are observed to be 1379 mA h g(-1), 1255 mA h g(-1) and 1360 mA h g(-1) that decrease to 750 mA h g(-1), 643 mA h g(-1) and 560 mA h g(-1) depending upon the chain length of grafted alkylamine on the graphene surface respectively. Electrochemical impedance spectral analysis reveals that the exchange current density of SnO2 pillared carbon based electrodes is higher, corroborating its enhanced electrochemical activity in comparison with GO based electrodes.

  4. Preparation and electrochemical properties of core-shell carbon coated Mn–Sn complex metal oxide as anode materials for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ruixue [Key Laboratory of Lithium Battery Materials of Jiangsu Province, Institute of chemical power sources, Soochow University, Suzhou 215006 (China); Fang, Guoqing; Liu, Weiwei [Key Laboratory of Lithium Battery Materials of Jiangsu Province, Institute of chemical power sources, Soochow University, Suzhou 215006 (China); Changzhou Institute of Energy Storage Materials and Devices, Changzhou 213000 (China); Xia, Bingbo; Sun, Hongdan; Zheng, Junwei [Key Laboratory of Lithium Battery Materials of Jiangsu Province, Institute of chemical power sources, Soochow University, Suzhou 215006 (China); Li, Decheng, E-mail: lidecheng@suda.edu.cn [Key Laboratory of Lithium Battery Materials of Jiangsu Province, Institute of chemical power sources, Soochow University, Suzhou 215006 (China)

    2014-02-15

    In this study, we synthesized a carbon coated Mn–Sn metal oxide composite with core-shell structure (MTO@C) via a simple glucose hydrothermal reaction and subsequent carbonization approach. When the MTO@C composite was applied as an anode material for lithium-ion batteries, it maintained a reversible capacity of 409 mA h g{sup −1} after 200 cycles at a current density of 100 mA g{sup −1}. The uniformed and continuous carbon layer formed on the MTO nanoparticles, effectively buffered the volumetric change of the active material and increased electronic conductivity, which thus prolonged the cycling performance of the MTO@C electrode.

  5. Preparation and electrochemical properties of core-shell carbon coated Mn–Sn complex metal oxide as anode materials for lithium-ion batteries

    International Nuclear Information System (INIS)

    Zhang, Ruixue; Fang, Guoqing; Liu, Weiwei; Xia, Bingbo; Sun, Hongdan; Zheng, Junwei; Li, Decheng

    2014-01-01

    In this study, we synthesized a carbon coated Mn–Sn metal oxide composite with core-shell structure (MTO@C) via a simple glucose hydrothermal reaction and subsequent carbonization approach. When the MTO@C composite was applied as an anode material for lithium-ion batteries, it maintained a reversible capacity of 409 mA h g −1 after 200 cycles at a current density of 100 mA g −1 . The uniformed and continuous carbon layer formed on the MTO nanoparticles, effectively buffered the volumetric change of the active material and increased electronic conductivity, which thus prolonged the cycling performance of the MTO@C electrode.

  6. Preparation and electrochemical properties of core-shell carbon coated Mn-Sn complex metal oxide as anode materials for lithium-ion batteries

    Science.gov (United States)

    Zhang, Ruixue; Fang, Guoqing; Liu, Weiwei; Xia, Bingbo; Sun, Hongdan; Zheng, Junwei; Li, Decheng

    2014-02-01

    In this study, we synthesized a carbon coated Mn-Sn metal oxide composite with core-shell structure (MTO@C) via a simple glucose hydrothermal reaction and subsequent carbonization approach. When the MTO@C composite was applied as an anode material for lithium-ion batteries, it maintained a reversible capacity of 409 mA h g-1 after 200 cycles at a current density of 100 mA g-1. The uniformed and continuous carbon layer formed on the MTO nanoparticles, effectively buffered the volumetric change of the active material and increased electronic conductivity, which thus prolonged the cycling performance of the MTO@C electrode.

  7. Polarization Induced Deterioration of Reinforced Concrete with CFRP Anode.

    Science.gov (United States)

    Zhu, Ji-Hua; Wei, Liangliang; Zhu, Miaochang; Sun, Hongfang; Tang, Luping; Xing, Feng

    2015-07-15

    This paper investigates the deterioration of reinforced concrete with carbon fiber reinforced polymer (CFRP) anode after polarization. The steel in the concrete was first subjected to accelerated corrosion to various extents. Then, a polarization test was performed with the external attached CFRP as the anode and the steel reinforcement as the cathode. Carbon fiber reinforced mortar and conductive carbon paste as contact materials were used to adhere the CFRP anode to the concrete. Two current densities of 1244 and 2488 mA/m², corresponding to the steel reinforcements were applied for 25 days. Electrochemical parameters were monitored during the test period. The deterioration mechanism that occurred at the CFRP/contact material interface was investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. The increase of feeding voltage and the failure of bonding was observed during polarization process, which might have resulted from the deterioration of the interface between the contact material and CFRP. The formation and accumulation of NaCl crystals at the contact material/CFRP interface were inferred to be the main causes of the failure at the interface.

  8. Combined system of accelerator molten-salt breeder (AMSB) apd molten-salt converter reactor (MSCR)

    International Nuclear Information System (INIS)

    Furukawa, K.; Kato, Y.; Ohmichi, T.; Ohno, H.

    1983-01-01

    A design and research program is discUssed of the development of accelerator molten-salt breeder (AMSB) consisting of a proton accelerator and a molten fluoride target. The target simultaneously serves as a blanket for fissionable material prodUction. An addition of some amoUnt of fissile nuclides to a melt expands the AMSB potentialities as the fissionable material production increases and the energy generation also grows up to the level of self-provision. Besides the blanket salts may be used as nuclear fuel for molten-salt converter reactor (MSCR). The combined AM SB+MSCR system has better parameters as compared to other breeder reactors, molten-salt breeder reactors (MSBR) included

  9. Alumina-coated and manganese monoxide embedded 3D carbon derived from avocado as high-performance anode for lithium-ion batteries

    Science.gov (United States)

    rehman, Wasif ur; Xu, Youlong; Du, Xianfeng; Sun, Xiaofei; Ullah, Inam; Zhang, Yuan; Jin, Yanling; Zhang, Baofeng; Li, Xifei

    2018-07-01

    Derived from avocado fruit, a three dimension (3D) carbon is prepared via a hydrothermal/pyrolysis process followed by embedding with MnO nanoparticles by a wet chemical method and coating with Al2O3 through an atomic layer deposition technique. The obtained material presents a hierarchical structure that MnO nanocrystals wrapped in 3D carbon and then encapsulated in a uniform Al2O3 layer with a thickness of about 5 nm. Benefiting from this hierarchical structure in which 3D carbon offers numerous electronic pathways to enhance the conductivity and Al2O3 nanolayer provide a shelter to keep away from dissolution of Mn4+ and volume changes during charge/discharge process. This material (marked as C/MnO@Al2O3) has exhibited high rate performance and excellent cyclability as an anode for lithium ion batteries. A high specific capacity of about 600 mA h g-1 is achieved at a current density of 1000 mA g-1 and the electrode can still deliver a high specific capacity of about 1165 mA h g-1 at 150 mA g-1 after 100 cycles. These results facilitate a green and high potential of anode materials towards promising devices for advance performance of lithium-ion batteries.

  10. Porous Nano-Si/Carbon Derived from Zeolitic Imidazolate Frameworks@Nano-Si as Anode Materials for Lithium-Ion Batteries

    International Nuclear Information System (INIS)

    Song, Yonghai; Zuo, Li; Chen, Shouhui; Wu, Jiafeng; Hou, Haoqing; Wang, Li

    2015-01-01

    Graphical abstract: Display Omitted -- Highlights: •The porous cage-like carbon/Si nanocomposites were synthesized based on nano-Si@ZIF-8-templatedmethod. •The nano-Si was uniformly embedded in porous amorphous carbon matrices. •The porous dodecahedral carbon framework effectively accommodates the volume variation of Si during the discharge/charge process. •The Si/C nanocomposites exhibit superior reversible capacity of 1168 mA h g −1 after 100 cycles. -- Abstract: Novel porous cage-like carbon (C)/nano-Si nanocomposites as anode materials for lithium-ion batteries (LIBs) was prepared based on nano-Si@zeolitic imidazolate frameworks (ZIF-8)-templated method. In this strategy, p-aminobenzoic acid was initially grafted onto nano-Si to form benzoic acid-functionalized nano-Si, and then nano-Si@ZIF-8 was constructed by alternately growing Zn(NO 3 ) 2 ·6H 2 O and 2-methylimidazolate on benzoic acid-functionalized nano-Si under ultrasound. The novel porous cage-like nano-Si/C nanocomposites were fabricated by pyrolyzing the resulted nano-Si@ZIF-8 and washing with HCl to remove off ZnO. Scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, Raman spectra and N 2 adsorption/desorption isotherms were employed to characterize the porous cage-like nano-Si/C nanocomposites. The resulted nano-Si/C nanocomposites as anode materials for LIBs showed a high reversible capacity of ∼1168 mA h g −1 at 100 mA g −1 after 100 cycles, which was higher than many previously reported Si/C nanocomposites. The porous nanostructure, high specific surface area and good electrical conductivity of the cage-like nano-Si/C nanocomposites contributed together to the good performance for LIBs. It might open up a new way for application of silicon materials

  11. Carbon and graphene double protection strategy to improve the SnOx electrode performance anodes for lithium-ion batteries

    Science.gov (United States)

    Zhu, Jian; Lei, Danni; Zhang, Guanhua; Li, Qiuhong; Lu, Bingan; Wang, Taihong

    2013-05-01

    SnOx is a promising high-capacity anode material for lithium-ion batteries (LIBs), but it usually exhibits poor cycling stability because of its huge volume variation during the lithium uptake and release process. In this paper, SnOx carbon nanofibers (SnOx@CNFs) are firstly obtained in the form of a nonwoven mat by electrospinning followed by calcination in a 0.02 Mpa environment at 500 °C. Then we use a simple mixing method for the synthesis of SnOx@CNF@graphene (SnOx@C@G) nanocomposite. By this technique, the SnOx@CNFs can be homogeneously deposited in graphene nanosheets (GNSs). The highly scattered SnOx@C@G composite exhibits enhanced electrochemical performance as anode material for LIBs. The double protection strategy to improve the electrode performance through producing SnOx@C@G composites is versatile. In addition, the double protection strategy can be extended to the fabrication of various types of composites between metal oxides and graphene nanomaterials, possessing promising applications in catalysis, sensing, supercapacitors and fuel cells.SnOx is a promising high-capacity anode material for lithium-ion batteries (LIBs), but it usually exhibits poor cycling stability because of its huge volume variation during the lithium uptake and release process. In this paper, SnOx carbon nanofibers (SnOx@CNFs) are firstly obtained in the form of a nonwoven mat by electrospinning followed by calcination in a 0.02 Mpa environment at 500 °C. Then we use a simple mixing method for the synthesis of SnOx@CNF@graphene (SnOx@C@G) nanocomposite. By this technique, the SnOx@CNFs can be homogeneously deposited in graphene nanosheets (GNSs). The highly scattered SnOx@C@G composite exhibits enhanced electrochemical performance as anode material for LIBs. The double protection strategy to improve the electrode performance through producing SnOx@C@G composites is versatile. In addition, the double protection strategy can be extended to the fabrication of various types of

  12. Behaviour of molten beryllium with ITER reference CFC SEPCARB NB31 under moisture

    Energy Technology Data Exchange (ETDEWEB)

    Lipa, M. [CEA/Cadarache-DSM/DRFC, Euratom-Association, Saint Paul Lez Durance F-13108 (France)], E-mail: manfred.lipa@cea.fr; Linke, J. [Forschungszentrum Juelich, Euratom-Association, Juelich D-52425 (Germany); Martin, G. [CEA/Cadarache-DSM/DRFC, Euratom-Association, Saint Paul Lez Durance F-13108 (France); Wessel, E. [Forschungszentrum Juelich, Euratom-Association, Juelich D-52425 (Germany)

    2007-10-15

    A dramatic exothermic reaction has been observed in Tore Supra with molten aluminium enclosed in a thermally loaded 2D carbon fibre reinforced carbon composite (CFC) tile, exposed after component removal to atmospheric moisture. This led to an important local destruction of the graphite matrix and fibre texture. Beryllium, as aluminium, a carbide forming metal, is foreseen for the ITER first wall armour. Since it can be expected that sputtered, molten and/or evaporated beryllium material will be transported to the hot CFC based divertor surface during normal and off-normal plasma operation, a preliminary reaction experiment has been performed in order to investigate to which extent the Be contaminated graphite matrix and fibre texture of 3D-CFC SEPCARB NB31 could be locally damaged ('erosion') following a subsequent long lasting air venting or a supposed in-vessel ingress of coolant (steam) event (ICE)

  13. Insight into effects of graphene in Li4Ti5O12/carbon composite with high rate capability as anode materials for lithium ion batteries

    International Nuclear Information System (INIS)

    Ding, Y.; Li, G.R.; Xiao, C.W.; Gao, X.P.

    2013-01-01

    Li 4 Ti 5 O 12 /carbon composites have shown promising high rate capability as anode materials for lithium ion batteries. In this paper, unique effects of graphene in Li 4 Ti 5 O 12 /carbon composites on electrochemical performances are focused by means of comparing Li 4 Ti 5 O 12 /graphene with Li 4 Ti 5 O 12 /conductive carbon black (CCB) and Li 4 Ti 5 O 12 . The investigated anode materials are synthesized by a facile hydrothermal method. The amount of graphene or CCB in the Li 4 Ti 5 O 12 /carbon composites is about 3 wt% measured by thermogravimetric (TG) analysis. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) show that Li 4 Ti 5 O 12 /graphene consists of small sized Li 4 Ti 5 O 12 nanocrystals supported on graphene nanosheets, while Li 4 Ti 5 O 12 /CCB comprises Li 4 Ti 5 O 12 nanocrystal aggregates coated nearly by graphited carbon. The electrochemical performances of these samples as anode materials for lithium ion batteries are investigated by galvanostatic charge–discharge method. Li 4 Ti 5 O 12 /graphene provides a superior rate capability. At the high current density of 1600 mA g −1 , the reversible capacity after 200 cycles is still more than 120 mAh g −1 , which is about 40% higher than that of Li 4 Ti 5 O 12 /CCB. Cyclic voltammetry (CV) demonstrates that stronger pseudocapacitive effect occurs on Li 4 Ti 5 O 12 /graphene than on Li 4 Ti 5 O 12 /CCB. This derived from the structure features that graphene-supported small Li 4 Ti 5 O 12 nanocrystals provide more surface active sites for the lithium ion insertion/extraction. The strong pseudocapacitive effect is responsible for the improvements of capacity and high-rate capability. Further, electrochemical impedance spectra (EIS) show that Li 4 Ti 5 O 12 /graphene electrode have lower charge transfer resistance and smaller diffusion impedance, indicating the obvious advantages in electrode kinetics over Li 4 Ti 5 O 12 and Li 4 Ti 5 O 12

  14. Capacitance-Assisted Sustainable Electrochemical Carbon Dioxide Mineralisation.

    Science.gov (United States)

    Lamb, Katie J; Dowsett, Mark R; Chatzipanagis, Konstantinos; Scullion, Zhan Wei; Kröger, Roland; Lee, James D; Aguiar, Pedro M; North, Michael; Parkin, Alison

    2018-01-10

    An electrochemical cell comprising a novel dual-component graphite and Earth-crust abundant metal anode, a hydrogen producing cathode and an aqueous sodium chloride electrolyte was constructed and used for carbon dioxide mineralisation. Under an atmosphere of 5 % carbon dioxide in nitrogen, the cell exhibited both capacitive and oxidative electrochemistry at the anode. The graphite acted as a supercapacitive reagent concentrator, pumping carbon dioxide into aqueous solution as hydrogen carbonate. Simultaneous oxidation of the anodic metal generated cations, which reacted with the hydrogen carbonate to give mineralised carbon dioxide. Whilst conventional electrochemical carbon dioxide reduction requires hydrogen, this cell generates hydrogen at the cathode. Carbon capture can be achieved in a highly sustainable manner using scrap metal within the anode, seawater as the electrolyte, an industrially relevant gas stream and a solar panel as an effective zero-carbon energy source. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  15. Dendrite-Free Sodium-Metal Anodes for High-Energy Sodium-Metal Batteries.

    Science.gov (United States)

    Sun, Bing; Li, Peng; Zhang, Jinqiang; Wang, Dan; Munroe, Paul; Wang, Chengyin; Notten, Peter H L; Wang, Guoxiu

    2018-05-31

    Sodium (Na) metal is one of the most promising electrode materials for next-generation low-cost rechargeable batteries. However, the challenges caused by dendrite growth on Na metal anodes restrict practical applications of rechargeable Na metal batteries. Herein, a nitrogen and sulfur co-doped carbon nanotube (NSCNT) paper is used as the interlayer to control Na nucleation behavior and suppress the Na dendrite growth. The N- and S-containing functional groups on the carbon nanotubes induce the NSCNTs to be highly "sodiophilic," which can guide the initial Na nucleation and direct Na to distribute uniformly on the NSCNT paper. As a result, the Na-metal-based anode (Na/NSCNT anode) exhibits a dendrite-free morphology during repeated Na plating and striping and excellent cycling stability. As a proof of concept, it is also demonstrated that the electrochemical performance of sodium-oxygen (Na-O 2 ) batteries using the Na/NSCNT anodes show significantly improved cycling performances compared with Na-O 2 batteries with bare Na metal anodes. This work opens a new avenue for the development of next-generation high-energy-density sodium-metal batteries. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Electrochemical Performance of Electrospun carbon nanofibers as free-standing and binder-free anodes for Sodium-Ion and Lithium-Ion Batteries

    International Nuclear Information System (INIS)

    Jin, Juan; Shi, Zhi-qiang; Wang, Cheng-yang

    2014-01-01

    Highlights: • Electrospun carbon nanofiber webs were prepared by pyrolysis of polyacrylonitrile. • The webs as binder-free and current collector-free electrodes for SIBs and LIBs. • Different layer spacing and pore size for Li and Na lead different electrochemical behavior. • Electrochemical performances of the electrodes were high. - Abstract: A series of hard carbon nanofiber-based electrodes derived from electrospun polyacrylonitrile (PAN) nanofibers (PAN-CNFs) have been fabricated by stabilization in air at about 280 °C and then carbonization in N 2 at heat treatment temperatures (HTT) between 800 and 1500 °C. The electrochemical performances of the binder-free, current collector-free carbon nanofiber-based anodes in lithium-ion batteries and sodium-ion batteries are systematically investigated and compared. We demonstrate the presence of similar alkali metal insertion mechanisms in both cases, but just the differences of the layer spacing and pore size available for lithium and sodium ion lead the discharge capacity delivered at sloping region and plateau region to vary from the kinds of alkali elements. Although the anodes in sodium-ion batteries show poorer rate capability than that in lithium-ion batteries, they still achieve a reversible sodium intercalation capacity of 275 mAh g −1 and similar cycling stability due to the conductive 3-D network, weakly ordered turbostratic structure and a large interlayer spacing between graphene sheets. The feature of high capacity and stable cycling performance makes PAN-CNFs to be promising candidates as electrodes in rechargeable sodium-ion batteries and lithium-ion batteries

  17. Experimental observations on electrorefining spent nuclear fuel in molten LiCl-KCl/liquid cadmium system

    International Nuclear Information System (INIS)

    Johnson, T. A.; Laug, D. V.; Li, S. X.; Sofu, T.

    1999-01-01

    Argonne National Laboratory (ANL) is currently performing a demonstration program for the Department of Energy (DOE) which processes spent nuclear fuel from the Experimental Breeder Reactor (EBR-II). One of the key steps in this demonstration program is electrorefining of the spent fuel in a molten LiCl-KCl/liquid cadmium system using a pilot scale electrorefiner (Mk-IV ER). This article summarizes experimental observations and engineering aspects for electrorefining spent fuel in the molten LiCl-KCl/liquid cadmium system. It was found that the liquid cadmium pool acted as an intermediate electrode during the electrorefining process in the ER. The cadmium level was gradually decreased due to its high vapor pressure and vaporization rate at the ER operational temperature. The low cadmium level caused the anode assembly momentarily to touch the ER vessel hardware, which generated a periodic current change at the salt/cathode interface and improved uranium recovery efficiency for the process. The primary current distributions calculated by numerical simulations were used in interpreting the experimental results

  18. High performance anode for advanced Li batteries

    Energy Technology Data Exchange (ETDEWEB)

    Lake, Carla [Applied Sciences, Inc., Cedarville, OH (United States)

    2015-11-02

    The overall objective of this Phase I SBIR effort was to advance the manufacturing technology for ASI’s Si-CNF high-performance anode by creating a framework for large volume production and utilization of low-cost Si-coated carbon nanofibers (Si-CNF) for the battery industry. This project explores the use of nano-structured silicon which is deposited on a nano-scale carbon filament to achieve the benefits of high cycle life and high charge capacity without the consequent fading of, or failure in the capacity resulting from stress-induced fracturing of the Si particles and de-coupling from the electrode. ASI’s patented coating process distinguishes itself from others, in that it is highly reproducible, readily scalable and results in a Si-CNF composite structure containing 25-30% silicon, with a compositionally graded interface at the Si-CNF interface that significantly improve cycling stability and enhances adhesion of silicon to the carbon fiber support. In Phase I, the team demonstrated the production of the Si-CNF anode material can successfully be transitioned from a static bench-scale reactor into a fluidized bed reactor. In addition, ASI made significant progress in the development of low cost, quick testing methods which can be performed on silicon coated CNFs as a means of quality control. To date, weight change, density, and cycling performance were the key metrics used to validate the high performance anode material. Under this effort, ASI made strides to establish a quality control protocol for the large volume production of Si-CNFs and has identified several key technical thrusts for future work. Using the results of this Phase I effort as a foundation, ASI has defined a path forward to commercialize and deliver high volume and low-cost production of SI-CNF material for anodes in Li-ion batteries.

  19. Electrochemical studies and analysis of 1–10 wt% UCl{sub 3} concentrations in molten LiCl–KCl eutectic

    Energy Technology Data Exchange (ETDEWEB)

    Hoover, Robert O., E-mail: roberthoover@vandals.uidaho.edu [Chemical and Materials Engineering Department and Nuclear Engineering Program, University of Idaho, Idaho Falls, Center for Advanced Energy Studies, 995 University Blvd, Idaho Falls, ID 83401 (United States); Shaltry, Michael R., E-mail: mshaltry@uidaho.edu [Chemical and Materials Engineering Department and Nuclear Engineering Program, University of Idaho, Idaho Falls, Center for Advanced Energy Studies, 995 University Blvd, Idaho Falls, ID 83401 (United States); Martin, Sean, E-mail: Sean.martin@xenuclear.com [Department of Engineering Physics, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI 53706 (United States); Sridharan, Kumar, E-mail: kumar@engr.wisc.edu [Department of Engineering Physics, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI 53706 (United States); Phongikaroon, Supathorn, E-mail: supathor@uidaho.edu [Chemical and Materials Engineering Department and Nuclear Engineering Program, University of Idaho, Idaho Falls, Center for Advanced Energy Studies, 995 University Blvd, Idaho Falls, ID 83401 (United States)

    2014-09-15

    Three electrochemical methods – cyclic voltammetry (CV), chronopotentiometry (CP), and anodic stripping voltammetry (ASV) – were applied to solutions of up to 10 wt% UCl{sub 3} in the molten LiCl–KCl eutectic salt at 500 °C to determine electrochemical properties and behaviors and to help provide a scientific basis for the development of an in situ electrochemical probe for determining the concentration of uranium in a used nuclear fuel electrorefiner. Diffusion coefficients of UCl{sub 4} and UCl{sub 3} were calculated to be (6.72 ± 0.360) × 10{sup −6} cm{sup 2}/s and (1.04 ± 0.17) × 10{sup −5} cm{sup 2}/s, respectively. Apparent standard reduction potentials were determined to be (−0.381 ± 0.013) V and (−1.502 ± 0.076) V vs. 5 mol% Ag/AgCl or (−1.448 ± 0.013) V and (−2.568 ± 0.076) V vs. Cl{sub 2}/Cl{sup −} for the U(IV)/U(III) and U(III)/U redox couples, respectively. In comparing this data with supercooled thermodynamic data to determine activity coefficients, the thermodynamic database used was important with resulting activity coefficients ranging from 2.34 × 10{sup −3} to 1.08 × 10{sup −2} for UCl{sub 4} and 4.94 × 10{sup −5} to 4.50 × 10{sup −4} for UCl{sub 3}. Of anodic stripping voltammetry and cyclic voltammetry anodic or cathodic peaks, the CV cathodic peak height divided by square root of scan rate was shown to be the most reliable method of determining UCl{sub 3} concentration in the molten salt.

  20. Electrolyte effects on the surface chemistry and cellular response of anodized titanium

    International Nuclear Information System (INIS)

    Ohtsu, Naofumi; Kozuka, Taro; Hirano, Mitsuhiro; Arai, Hirofumi

    2015-01-01

    Highlights: • Ti samples were anodized using various electrolytes. • Anodization decreased carbon adsorption, improving hydrophilicity. • Improved hydrophilicity led to improved cellular attachment. • Only one electrolyte showed any heteroatom incorporation into the TiO 2 layer. • Choice of electrolyte played no role on the effects of anodization. - Abstract: Anodic oxidation of titanium (Ti) material is used to enhance biocompatibility, yet the effects of various electrolytes on surface characteristics and cellular behavior have not been completely elucidated. To investigate this topic, oxide layers were produced on Ti substrates by anodizing them in aqueous electrolytes of (NH 4 ) 2 O·5B 2 O 3 , (NH 4 ) 2 SO 4 , or (NH 4 ) 3 PO 4 , after which their surface characteristics and cellular responses were examined. Overall, no surface differences between the electrolytes were visually observed. X-ray photoelectron spectroscopy (XPS) revealed that the anodized surfaces are composed of titanium dioxide (TiO 2 ), while incorporation from electrolyte was only observed for (NH 4 ) 3 PO 4 . Surface adsorption of carbon contaminants during sterilization was suppressed by anodization, leading to lower water contact angles. The attachment of MC3T3-E1 osteoblast-like cells was also improved by anodization, as evidenced by visibly enlarged pseudopods. This improved attachment performance is likely due to TiO 2 formation. Overall, electrolyte selection showed no effect on either surface chemistry or cellular response of Ti materials

  1. Electrochemical properties of SnO2/carbon composite materials as anode material for lithium-ion batteries

    International Nuclear Information System (INIS)

    Wang Jie; Zhao Hailei; Liu Xiaotong; Wang Jing; Wang Chunmei

    2011-01-01

    Highlights: → SnO 2 /carbon powders with a cauliflower-like particle structure were synthesized. → Post-annealing can improve the electrochemical properties of SnO 2 /C composite. → The 500 deg. C-annealed SnO 2 /C shows the best electrochemical performance. → The lithium ion diffusion coefficients of the SnO 2 /C electrodes were calculated. - Abstract: SnO 2 /carbon composite anode materials were synthesized from SnCl 4 .5H 2 O and sucrose via a hydrothermal route and a post heat-treatment. The synthesized spherical SnO 2 /carbon powders show a cauliflower-like micro-sized structure. High annealing temperature results in partial reduction of SnO 2 . Metallic Sn starts to emerge at 500 deg. C. High Sn content in SnO 2 /carbon composite is favorable for the increase of initial coulombic efficiency but not for the cycling stability. The SnO 2 /carbon annealed at 500 deg. C exhibits high specific capacity (∼400 mAh g -1 ), stable cycling performance and good rate capability. The generation of Li 2 O in the first lithiation process can prevent the aggregation of active Sn, while the carbon component can buffer the big volume change caused by lithiation/delithiation of active Sn. Both of them make contribution to the better cycle stability.

  2. Electrodeposited gold nanoparticles on carbon nanotube-textile: Anode material for glucose alkaline fuel cells

    KAUST Repository

    Pasta, Mauro; Hu, Liangbing; La Mantia, Fabio; Cui, Yi

    2012-01-01

    In the present paper we propose a new anode material for glucose-gluconate direct oxidation fuel cells prepared by electrodepositing gold nanoparticles onto a conductive textile made by conformally coating single walled carbon nanotubes (SWNT) on a polyester textile substrate. The electrodeposition conditions were optimized in order to achieve a uniform distribution of gold nanoparticles in the 3D porous structure of the textile. On the basis of previously reported studies, the reaction conditions (pH, electrolyte composition and glucose concentration) were tuned in order to achieve the highest oxidation rate, selectively oxidizing glucose to gluconate. The electrochemical characterization was carried out by means of cyclic voltammetry. © 2012 Elsevier B.V. All rights reserved.

  3. Electrodeposited gold nanoparticles on carbon nanotube-textile: Anode material for glucose alkaline fuel cells

    KAUST Repository

    Pasta, Mauro

    2012-06-01

    In the present paper we propose a new anode material for glucose-gluconate direct oxidation fuel cells prepared by electrodepositing gold nanoparticles onto a conductive textile made by conformally coating single walled carbon nanotubes (SWNT) on a polyester textile substrate. The electrodeposition conditions were optimized in order to achieve a uniform distribution of gold nanoparticles in the 3D porous structure of the textile. On the basis of previously reported studies, the reaction conditions (pH, electrolyte composition and glucose concentration) were tuned in order to achieve the highest oxidation rate, selectively oxidizing glucose to gluconate. The electrochemical characterization was carried out by means of cyclic voltammetry. © 2012 Elsevier B.V. All rights reserved.

  4. Electrodeposition in molten salts of metals used in nuclear industry: hafnium and uranium

    International Nuclear Information System (INIS)

    Serrano, K.

    1998-01-01

    The aim of this work is to study the electrodeposition in molten salts of metals used in nuclear industry: hafnium and uranium. The experiment is carried out in a molten alkaline halogenide medium in a temperature range between 670 and 750 degrees Celsius. The first part of this work concerns more particularly the electrochemical behaviour of the hafnium and uranium ions in the electrolytic solution. The reduction mechanisms of these ions have been studied by the use of three methods: cyclic voltametry, chrono-potentiometry and square wave voltametry. Results have shown that the process of metal deposition is difficult to explain because secondary reactions (as for instance: adsorption phenomena or cathodic deposit dissolution) occur. The uranium germination has then been studied by modelling of chrono-amperograms. The experiments have shown that the deposition is the result of the initial uranium crystal growth and depends on the electrolyte diffusion. The second part of this work deals with the implementation of hafnium and uranium deposition taking into account the preceding mechanistic studies. Depositions have all been observed by physical methods as for instance scanning electron microscopy. Particular experimental solutions (soluble anode, addition of fluoride ions to the electrolyte) have been used. The obtained deposition of hafnium is smooth and adheres very well to the substrate. The uranium depositions have been implemented with the use of a soluble anode. Uranium is deposited in a dendritic shape to the cathode. It has also been shown that the electro-kinetic parameters (temperature, uranium ions concentration, current density) have not an important influence on the dendritic morphology of the deposition. This morphology could be the consequence of particular convection movements to the surface of the cathode. (O.M.)

  5. Development of Carbon and Sulphur Tolerant Anodes of Solid Oxide Fuel Cells

    Science.gov (United States)

    2010-01-14

    Thus, in this Chapter we report a detail study of the electrode behavior of pure Ni/GDC and Ni/YSZ cermet anodes in weakly humidified H2 fuel...impedance behavior for the oxidation reaction in hydrogen, methane and ethanol over a pure and Pd-impregnated Ni/GDC anode of SOFC were also studied ...surfaces [1]. So Ni/YSZ based cermet anodes have a very low tolerance to fuels containing H2S even at a very low level (ppm) [2]. Thus, the development of

  6. Evaluation of MHD materials for use in high-temperature fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Guidotti, R.

    1978-06-15

    The MHD and high-temperature fuel cell literature was surveyed for data pertaining to materials properties in order to identify materials used in MHD power generation which also might be suitable for component use in high-temperature fuel cells. Classes of MHD-electrode materials evaluated include carbides, nitrides, silicides, borides, composites, and oxides. Y/sub 2/O/sub 3/-stabilized ZrO/sub 2/ used as a reference point to evaluate materials for use in the solid-oxide fuel cell. Physical and chemical properties such as electrical resistivity, coefficient of thermal expansion, and thermodynamic stability toward oxidation were used to screen candidate materials. A number of the non-oxide ceramic MHD-electrode materials appear promising for use in the solid-electrolyte and molten-carbonate fuel cell as anodes or anode constituents. The MHD-insulator materials appear suitable candidates for electrolyte-support tiles in the molten-carbonate fuel cells. The merits and possible problem areas for these applications are discussed and additional needed areas of research are delineated.

  7. High Capacity of Hard Carbon Anode in Na-Ion Batteries Unlocked by PO x Doping

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhifei; Ma, Lu; Surta, Todd Wesley; Bommier, Clement; Jian, Zelang; Xing, Zhenyu; Stickle, William F.; Dolgos, Michelle; Amine, Khalil; Lu, Jun; Wu, Tianpin; Ji, Xiulei

    2016-08-12

    The capacity of hard carbon anodes in Na-ion batteries 2.5 rarely reaches values beyond 300 mAh/g. We report that doping POx into local structures of hard carbon increases its reversible capacity from 283 to 359 mAh/g. We confirm that the doped POx is redox inactive by X-ray adsorption near edge structure measurements, thus not contributing to the higher capacity. We observe two significant changes of hard carbon's local structures caused by doping. First, the (002) d-spacing inside the turbostratic nanodomains is increased, revealed by both laboratory and synchrotron X-ray diffraction. Second, doping turns turbostratic nanodomains more defective along ab planes, indicated by neutron total scattering and the associated pair distribution function studies. The local structural changes of hard carbon are correlated to the higher capacity, where both the plateau and slope regions in the potential profiles are enhanced. Our study demonstrates that Na-ion storage in hard carbon heavily depends on carbon local structures, where such structures, despite being disordered, can be tuned toward unusually high capacities.

  8. Molten V2O5/Cs0.9K0.9Na0.2S2O7 and V2O5/K2S2O7 catalysts as electrolytes in an electrocatalytic membrane separation device for SO2 removal

    DEFF Research Database (Denmark)

    Rasmussen, Søren Birk; Eriksen, Kim Michael; Fehrmann, Rasmus

    2002-01-01

    Bench scale fuel cell tests have been carried out on the SO2 oxidation catalyst systems V2O5/M2S2O7 (M = alkali) used as electrolytes in a standard molten carbonate fuel cell (MCFC) fuel cell setup for removal of SO2 from power plant flue gases. Porous LixNi(1-x)O electrodes were used both as anode...... and cathode. The cleaning cell removes SO2 when a potential is applied across the membrane, potentially providing cheap and ecological viable means for regeneration of SO2 from off-gases into high quality H2SO4. Results show that successful removal of up to 80% SO2 at 450 degreesC can be achieved...

  9. Facile synthesis of Fe4N/Fe2O3/Fe/porous N-doped carbon nanosheet as high-performance anode for lithium-ion batteries

    Science.gov (United States)

    Zhang, Dan; Li, Guangshe; Yu, Meijie; Fan, Jianming; Li, Baoyun; Li, Liping

    2018-04-01

    Iron nitrides are considered as highly promising anode materials for lithium-ion batteries because of their nontoxicity, high abundance, low cost, and higher electrical conductivity. Unfortunately, their limited synthesis routes are available and practical application is still hindered by their fast capacity decay. Herein, a facile and green route is developed to synthesize Fe4N/Fe2O3/Fe/porous N-doped carbon nanosheet composite. The size of Fe4N/Fe2O3/Fe particles is small (10-40 nm) and they are confined in porous N-doped carbon nanosheet. These features are conducive to accommodate volume change well, shorten the diffusion distance and further elevate electrical conductivity. When tested as anode material for lithium-ion batteries, a high discharge capacity of 554 mA h g-1 after 100 cycles at 100 mA g-1 and 389 mA h g-1 after 300 cycles at 1000 mA g-1 are retained. Even at 2000 mA g-1, a high capacity of 330 mA h g-1 can be achieved, demonstrating superior cycling stability and rate performance. New prospects will be brought by this work for the synthesis and the potential application of iron nitrides materials as an anode for LIBs.

  10. Molten salt reactors

    International Nuclear Information System (INIS)

    Bouchter, J.C.; Dufour, P.; Guidez, J.; Simon, N.; Renault, C.

    2014-01-01

    Molten salt reactors are one of the 6 concepts retained for the 4. generation of nuclear reactors. The principle of this reactor is very innovative: the nuclear fuel is dissolved in the coolant which allows the online reprocessing of the fuel and the online recovery of the fission products. A small prototype: the Molten Salt Reactor Experiment (MSRE - 8 MWt) was operating a few years in the sixties in the USA. The passage towards a fast reactor by the suppression of the graphite moderator leads to the concept of Molten Salt Fast Reactor (MSFR) which is presently studied through different European projects such as MOST, ALISIA and EVOL. Worldwide the main topics of research are: the adequate materials resisting to the high level of corrosiveness of the molten salts, fuel salt reprocessing, the 3-side coupling between neutron transport, thermohydraulics and thermo-chemistry, the management of the changing chemical composition of the salt, the enrichment of lithium with Li 7 in the case of the use of lithium fluoride salt and the use of MSFR using U 233 fuel (thorium cycle). The last part of the article presents a preliminary safety analysis of the MSFR. (A.C.)

  11. CoFe2O4/carbon nanotube aerogels as high performance anodes for lithium ion batteries

    Directory of Open Access Journals (Sweden)

    Xin Sun

    2017-04-01

    Full Text Available High-performance lithium ion batteries (LIBs require electrode material to have an ideal electrode construction which provides fast ion transport, short solid-state ion diffusion, large surface area, and high electric conductivity. Herein, highly porous three-dimensional (3D aerogels composed of cobalt ferrite (CoFe2O4, CFO nanoparticles (NPs and carbon nanotubes (CNTs are prepared using sustainable alginate as the precursor. The key feature of this work is that by using the characteristic egg-box structure of the alginate, metal cations such as Co2+ and Fe3+ can be easily chelated via an ion-exchange process, thus binary CFO are expected to be prepared. In the hybrid aerogels, CFO NPs interconnected by the CNTs are embedded in carbon aerogel matrix, forming the 3D network which can provide high surface area, buffer the volume expansion and offer efficient ion and electron transport pathways for achieving high performance LIBs. The as-prepared hybrid aerogels with the optimum CNT content (20 wt% delivers excellent electrochemical properties, i.e., reversible capacity of 1033 mAh g−1 at 0.1 A g−1 and a high specific capacity of 874 mAh g−1 after 160 cycles at 1 A g−1. This work provides a facile and low cost route to fabricate high performance anodes for LIBs. Keywords: Alginate, Aerogels, Cobalt ferrite, Anode, Lithium-ion battery

  12. MoO2-ordered mesoporous carbon nanocomposite as an anode material for lithium-ion batteries.

    Science.gov (United States)

    Zeng, Lingxing; Zheng, Cheng; Deng, Cuilin; Ding, Xiaokun; Wei, Mingdeng

    2013-03-01

    In the present work, the nanocomposite of MoO2-ordered mesoporous carbon (MoO2-OMC) was synthesized for the first time using a carbon thermal reduction route and the mesoporous carbon as the nanoreactor. The synthesized nanocomposite was characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), N2 adsorption-desorption, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) measurements. Furthermore, this nanocomposite was used as an anode material for Li-ion intercalation and exhibited large reversible capacity, high rate performance, and good cycling stability. For instance, a high reversible capacity of 689 mAh g(-1) can remain after 50 cycles at a current density of 50 mA g(-1). It is worth mentioning that the MoO2-OMC nanocomposite electrode can attain a high reversible capacity of 401 mAh g(-1) at a current density as high as 2 A g(-1). These results might be due to the intrinsic characteristics of nanocomposite, which offered a better accommodation of the strain and volume changes and a shorter path for Li-ion and electron transport, leading to the improved capacity and enhanced rate capability.

  13. Carbon-covered Fe_3O_4 hollow cubic hierarchical porous composite as the anode material for lithium-ion batteries

    International Nuclear Information System (INIS)

    Chen, Shouhui; Zhou, Rihui; Chen, Yaqin; Fu, Yuanyuan; Li, Ping; Song, Yonghai; Wang, Li

    2017-01-01

    In this work, Prussian blue nanocrystals, a kind of cubic metal-organic frameworks, was firstly covered by a uniform layer of resorcinol-formaldehyde (RF) resin, and then followed with heat treatment at different pyrolysis temperatures. The effects of pyrolysis temperature on the morphologies, phase, pore size, and electrochemical performance of the pyrolysis products were studied in this work. The composite generated at 600 "∘C, FexC600, was a hollow cubic composite of Fe_3O_4 covered by a thin RF-derived carbon layer. The carbon layer on FexC600 was a robust and conductive protective layer, which can accommodate Fe_3O_4 NPs and withstand the huge volume change of Fe_3O_4 during the process of discharge and charge. When used as anodes for lithium-ion batteries, FexC600 showed excellent electrochemical performance. It delivered a discharge capacity of 1126 mAh g"−"1 with a coulombic efficiency of 98.8% at the current density of 100 mA g"−"1 after 100 times discharge/charge cycling. It even delivered a capacity of 492 mAh g"−"1 at the current density of 500 mA g"−"1. This cubic hollow composite would be a promising alternative anode material for lithium-ion batteries.

  14. Anodic stripping voltammetry of antimony using gold nanoparticle-modified carbon screen-printed electrodes

    International Nuclear Information System (INIS)

    Dominguez Renedo, Olga; Arcos Martinez, M. Julia

    2007-01-01

    Carbon screen-printed electrodes (CSPE) modified with gold nanoparticles present an interesting alternative in the determination of antimony using differential pulse anodic stripping voltammetry. Metallic gold nanoparticles deposits have been obtained by direct electrochemical deposition. Scanning electron microscopy measurements show that the electrochemically synthesized gold nanoparticles are deposited in aggregated form. Any undue effects caused by the presence of foreign ions in the solution were also analyzed to ensure that common interferents in the determination of antimony by ASV. The detection limit for Sb(III) obtained was 9.44 x 10 -10 M. In terms of reproducibility, the precision of the above mentioned method in %R.S.D. values was calculated at 2.69% (n = 10). The method was applied to determine levels of antimony in seawater samples and pharmaceutical preparations

  15. Organic Light Emitting Diodes with Opal Photonic Crystal Layer and Carbon Nanotube Anode

    Science.gov (United States)

    Ovalle Robles, Raquel; Del Rocio Nava, Maria; Williams, Christopher; Zhang, Mei; Fang, Shaoli; Lee, Sergey; Baughman, Ray; Zakhidov, Anvar

    2007-03-01

    We report electroluminescence intensity and spectral changes in light emission from organic light emitting diode (OLEDs) structures, which have thin transparent films of opal photonic crystal (PC). The anode in such PC-OLED is laminated on opal layer from free standing optically transparent multiwall carbon nanotubes (T-CNT) sheets made by dry spinning from CVD grown forests. Silica and polystyrene opal films were grown on glass substrates by vertical sedimentation in colloids in thermal baths and the particle size of opal spheres ranges from 300 nm to 450 nm. The use of T-CNTs, (coated by PEDOT-PSS to avoid shorting) as hole injector, allows to eliminate the use of vacuum deposition of metals and permits to achieve tunneling hole injection regime from CNT tips into Alq^3 emission layer

  16. Carbon with Expanded and Well-Developed Graphene Planes Derived Directly from Condensed Lignin as a High-Performance Anode for Sodium-Ion Batteries.

    Science.gov (United States)

    Yoon, Dohyeon; Hwang, Jieun; Chang, Wonyoung; Kim, Jaehoon

    2018-01-10

    In this study, we demonstrate that lignin, which constitutes 30-40 wt % of the terrestrial lignocellulosic biomass and is produced from second generation biofuel plants as a cheap byproduct, is an excellent precursor material for sodium-ion battery (NIB) anodes. Because it is rich in aromatic monomers that are highly cross-linked by ether and condensed bonds, the lignin material carbonized at 1300 °C (C-1300) in this study has small graphitic domains with well-developed graphene layers, a large interlayer spacing (0.403 nm), and a high micropore surface area (207.5 m 2 g -1 ). When tested as an anode in an NIB, C-1300 exhibited an initial Coulombic efficiency of 68% and a high reversible capacity of 297 mA h g -1 at 50 mA g -1 after 50 cycles. The high capacity of 199 mA h g -1 at less than 0.1 V with a flat voltage profile and an extremely low charge-discharge voltage hysteresis (sugar-derived carbons and a low-temperature carbonized sample (900 °C), the reasons for the excellent performance of C-1300 were determined to result from facilitated Na + -ion transport to the graphitic layer and the microporous regions that penetrate through the less defective and enlarged interlayer spacings.

  17. Morphological control of three-dimensional carbon nanotube anode for high-capacity lithium-ion battery

    Science.gov (United States)

    Kang, Chiwon; Lee, Hoo-Jeong

    2018-05-01

    In this paper, we report the results of modulating the processing conditions (mainly, temperature) of a two-step method consisting of sputtering deposition of a Ni catalytic layer and chemical vapor deposition (CVD) of carbon nanotubes (CNTs) on a three-dimensional (3D)-structured Cu mesh to control the morphology of CNTs for advanced Li-ion battery (LIB) applications. We disclosed that CNT growth at a low temperature (700 °C) produced small-diameter CNTs (CNT_S) with an average diameter of ∼20 nm, while that at a high temperature (750 °C) produced large-diameter CNTs (CNT_L) with an average diameter of 200–300 nm. The high-resolution transmission electron microscopy (HR-TEM) and Raman analyses manifested poorly crystalline CNTs for both samples. CNTS showed a specific capacity of 476 mAh g‑1, which is ∼176% superior to that of CNTL (271 mAh g‑1) and ∼128% higher than the theoretical capacity of the state-of-the-art graphites and recently reported nanostructured carbon-based anode materials.

  18. Operation of molten carbonate fuel cells with different biogas sources: A challenging approach for field trials

    Science.gov (United States)

    Trogisch, S.; Hoffmann, J.; Daza Bertrand, L.

    In the past years research in the molten carbonate fuel cells (MCFC) area has been focusing its efforts on the utilisation of natural gas as fuel (S. Geitmann, Wasserstoff- & Brennstoffzellen-Projekte, 2002, ISBN 3-8311-3280-1). In order to increase the advantages of this technology, an international consortium has worked on the utilisation of biogas as fuel in MCFC. During the 4 years lasting RTD project EFFECTIVE two different gas upgrading systems have been developed and constructed together with two mobile MCFC test beds which were operated at different locations for approximately 2.000-5.000 h in each run with biogas from different origins and quality. The large variety of test locations has enabled to gather a large database for assessing the effect of the different biogas qualities on the complete system consisting of the upgrading and the fuel cell systems. The findings are challenging. This article also aims at giving an overview of the advantages of using biogas as fuel for fuel cells.

  19. Amorphous-silicon@silicon oxide/chromium/carbon as an anode for lithium-ion batteries with excellent cyclic stability

    International Nuclear Information System (INIS)

    Li, Mingqi; Gu, Jingwei; Feng, Xiaofang; He, Hongyan; Zeng, Chunmei

    2015-01-01

    Highlights: • A new amorphous-Si@SiO x /Cr/carbon anode composite for lithium-ion batteries is synthesized by a simple method. • At a current density of 100 mA g −1 , this as-prepared composite exhibit a stable discharge capacity of about 810 mAh g −1 with good capacity retention up to 200 cycles. Even at a current density of 800 mA g −1 , a stable discharge capacity of 570 mAh g −1 can be obtained. • This work creates a new method to improve the electrochemical performance of SiO-based electrode materials. - Abstract: A new amorphous-Si@SiO x /Cr/carbon (a-Si@SiO x /Cr/C) anode composite for lithium-ion batteries is synthesized, using SiO, chromium powder and graphite as starting materials. X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), scanning electron microscope (SEM) and high resolution transmission electron microscope (HRTEM) are employed to characterize the composition, morphology and microstructure of the composite. Coin-type cells are assembled to investigate the electrochemical behaviors of the as-prepared composites by constant current charge–discharge technique, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results show that chromium facilitates the crush of Si@SiO x and graphite during milling, and thus improves their mutual dispersion in the composite. When cycled at 100 mA g −1 , the a-Si@SiO x /Cr/C exhibits a stable discharge capacity of about 810 mAh g −1 (calculated on the mass of a-Si@SiO x /Cr/C) with good capacity retention up to 200 cycles. The improved electrochemical performance is attributed to the reduced particle size of a-Si@SiO x and the synergistic effect of carbon and chromium

  20. Molten fuel studies at Winfrith

    International Nuclear Information System (INIS)

    Edwards, A.J.; Knowles, J.B.; Tattersall, R.B.

    1988-01-01

    This report describes the experimental facilities available for molten fuel studies at Winfrith. These include a large facility capable of testing components at full LMFBR subassembly scale and also a high pressure facility for experiments at pressures up to 25 MPa, covering the whole range of temperatures and pressures of interest for the PWR. If the hypothetical accident conditions initiating the release of molten fuel do not produce an explosive transfer of thermal energy on contact of molten fuel with the reactor coolant, then an intermediate rate of heat transfer over several hundred milliseconds may occur. Theoretical work is described which is being carried out to predict the resulting pressurisation and the degree of mechanical loading on the reactor structure. Finally the current programme of molten fuel studies and recent progress are reviewed, and future plans, which are chiefly focussed on the study of thermal interactions between molten fuel and sodium coolant for the LMFBR are outlined. (author)

  1. Exploring Cu2O/Cu cermet as a partially inert anode to produce aluminum in a sustainable way

    International Nuclear Information System (INIS)

    Feng, Li-Chao; Xie, Ning; Shao, Wen-Zhu; Zhen, Liang; Ivanov, V.V.

    2014-01-01

    Highlights: • Cu 2 O/Cu cermet was used as a candidate partially inert anode material to produce aluminum alloys. • The thermal corrosion behavior of Cu 2 O/Cu was investigated in molten salt at 960 °C. • The corrosion rate is largely governed by the geometrical structures of Cu in the prepared samples. • The corrosion rate increases with decreasing sizes and increasing filling contents of Cu phase. • The corrosion rate was 1.8–9 cm/y and the Cu contents is less than 6.2 wt.% in the produced aluminum. - Abstract: As an energy-intensive process, aluminum production by the Hall–Héroult method accounts for significant emissions of CO 2 and some toxic greenhouse gases. The utilization of an inert anode in place of a carbon anode was considered as a revolutionary technique to solve most of the current environmental problems resulting from the Hall–Héroult process. However, the critical property requirements of the inert anode materials significantly limit the application of this technology. In light of the higher demand for aluminum alloys than for pure aluminum, a partially inert anode was designed to produce aluminum alloys in a more sustainable way. Here, Cu 2 O/Cu cermet was chosen as the material of interest. The thermal corrosion behavior of Cu 2 O/Cu was investigated in Na 3 AlF 6 –CaF 2 –Al 2 O 3 electrolyte at 960 °C to elucidate the corrosion mechanisms of this type of partially inert anode for the production of aluminum or aluminum alloys. Furthermore, the effects of the geometrical structure of the Cu phase on the thermal corrosion behavior of Cu 2 O/Cu cermet in the electrolyte were investigated as well. The thermal corrosion rate was evaluated by the weight loss method and the results show that the samples prepared with branch-like Cu have higher thermal corrosion rate than those prepared with spherical Cu, and the corrosion rate increases with decreasing size and increasing filling content of Cu phase. The calculated corrosion rate

  2. Development of internal manifold heat exchanger (IMHEX reg sign ) molten carbonate fuel cell stacks

    Energy Technology Data Exchange (ETDEWEB)

    Marianowski, L.G.; Ong, E.T.; Petri, R.J.; Remick, R.J.

    1991-01-01

    The Institute of Gas Technology (IGT) has been in the forefront of molten carbonate fuel cell (MCFC) development for over 25 years. Numerous cell designs have been tested and extensive tests have been performed on a variety of gas manifolding alternatives for cells and stacks. Based upon the results of these performance tests, IGT's development efforts started focusing on an internal gas manifolding concept. This work, initiated in 1988, is known today as the IMHEX{reg sign} concept. MCP has developed a comprehensive commercialization program loading to the sale of commercial units in 1996. MCP's role is in the manufacture of stack components, stack assembly, MCFC subsystem testing, and the design, marketing and construction of MCFC power plants. Numerous subscale (1 ft{sup 2}) stacks have been operated containing between 3 and 70 cells. These tests verified and demonstrated the viability of internal manifolding from technical (no carbonate pumping), engineering (relaxed part dimensional tolerance requirements), and operational (good gas sealing) aspects. Simplified fabrication, ease of assembly, the elimination of external manifolds and all associated clamping requirements has significantly lowered anticipated stack costs. Ongoing 1 ft{sup 2} stack testing is generating performance and endurance characteristics as a function of system specified operating conditions. Commercial-sized, full-area stacks (10 ft{sup 2}) are in the process of being assembled and will be tested in November. This paper will review the recent developments the MCFC scale-up and manufacture work of MCP, and the research and development efforts of IGT which support those efforts. 17 figs.

  3. Development of internal manifold heat exchanger (IMHEX reg-sign) molten carbonate fuel cell stacks

    International Nuclear Information System (INIS)

    Marianowski, L.G.; Ong, E.T.; Petri, R.J.; Remick, R.J.

    1991-01-01

    The Institute of Gas Technology (IGT) has been in the forefront of molten carbonate fuel cell (MCFC) development for over 25 years. Numerous cell designs have been tested and extensive tests have been performed on a variety of gas manifolding alternatives for cells and stacks. Based upon the results of these performance tests, IGT's development efforts started focusing on an internal gas manifolding concept. This work, initiated in 1988, is known today as the IMHEX reg-sign concept. MCP has developed a comprehensive commercialization program loading to the sale of commercial units in 1996. MCP's role is in the manufacture of stack components, stack assembly, MCFC subsystem testing, and the design, marketing and construction of MCFC power plants. Numerous subscale (1 ft 2 ) stacks have been operated containing between 3 and 70 cells. These tests verified and demonstrated the viability of internal manifolding from technical (no carbonate pumping), engineering (relaxed part dimensional tolerance requirements), and operational (good gas sealing) aspects. Simplified fabrication, ease of assembly, the elimination of external manifolds and all associated clamping requirements has significantly lowered anticipated stack costs. Ongoing 1 ft 2 stack testing is generating performance and endurance characteristics as a function of system specified operating conditions. Commercial-sized, full-area stacks (10 ft 2 ) are in the process of being assembled and will be tested in November. This paper will review the recent developments the MCFC scale-up and manufacture work of MCP, and the research and development efforts of IGT which support those efforts. 17 figs

  4. Sampling device for radioactive molten salt

    International Nuclear Information System (INIS)

    Shindo, Masato

    1998-01-01

    The present invention provides a device for accurately sampling molten salts to which various kinds of metals in a molten salt storage tank are mixed for analyzing them during a spent fuel dry type reprocessing. Namely, the device comprises a sampling tube having an opened lower end to be inserted into the radioactive molten salts stored in a tank and keeps reduced pressure from the upper end, and a pressure reducing pipeline having one end connected to the sampling tube and other end connected to an evacuating pump. In this device, the top end of the sampling tube is inserted to a position for sampling the radioactive molten salts (molten salts). The pressure inside the evacuating pipeline connected to the upper portion of the sampling tube is reduced for a while. In this case, the inside of the pressure reducing pipeline is previously evacuated by the evacuating pump so as to keep a predetermined pressure. Since the pressure in the sampling tube is lowered, molten salts are inserted into the sampling tube, the sampling tube is withdrawn, and the molten salts flown in the sampling tube are analyzed. (I.S.)

  5. Rational design of Sn/SnO{sub 2}/porous carbon nanocomposites as anode materials for sodium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiaojia [Tianjin International Joint Research Centre of Surface Technology for Energy Storage Materials, College of Physics and Materials Science, Tianjin Normal University, Tianjin 300387 (China); Li, Xifei, E-mail: xfli2011@hotmail.com [Tianjin International Joint Research Centre of Surface Technology for Energy Storage Materials, College of Physics and Materials Science, Tianjin Normal University, Tianjin 300387 (China); Center for Advanced Energy Materials and Devices, Xi’an University of Technology, Xi’an 710048 (China); Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Collaborative Innovation Center of Chemical Science and Engineering, College of Chemistry, Nankai University, Tianjin 300071 (China); Fan, Linlin; Yu, Zhuxin; Yan, Bo; Xiong, Dongbin; Song, Xiaosheng; Li, Shiyu [Tianjin International Joint Research Centre of Surface Technology for Energy Storage Materials, College of Physics and Materials Science, Tianjin Normal University, Tianjin 300387 (China); Adair, Keegan R. [Nanomaterials and Energy Lab., Department of Mechanical and Materials Engineering, Western University, London, Ontario N6A 5B9 (Canada); Li, Dejun, E-mail: dejunli@mail.tjnu.edu.cn [Tianjin International Joint Research Centre of Surface Technology for Energy Storage Materials, College of Physics and Materials Science, Tianjin Normal University, Tianjin 300387 (China); Sun, Xueliang, E-mail: xsun9@uwo.ca [Nanomaterials and Energy Lab., Department of Mechanical and Materials Engineering, Western University, London, Ontario N6A 5B9 (Canada); Tianjin International Joint Research Centre of Surface Technology for Energy Storage Materials, College of Physics and Materials Science, Tianjin Normal University, Tianjin 300387 (China)

    2017-08-01

    Highlights: • Sn/SnO{sub 2}/porous carbon nanocomposites are rationally designed via a facile strategy. • The porous carbon mitigates the volume change and poor conductivity of Sn/SnO{sub 2}. • The nanocomposites exhibit the enhanced sodium storage performance. - Abstract: Sodium-ion batteries (SIBs) have successfully attracted considerable attention for application in energy storage, and have been proposed as an alternative to lithium ion batteries (LIBs) due to the abundance of sodium resources and low price. Sn has been deemed as a promising anode material in SIBs which holds high theoretical specific capacity of 845 mAh g{sup −1}. In this work we design nanocomposite materials consisting of porous carbon (PC) with SnO{sub 2} and Sn (Sn/SnO{sub 2}/PC) via a facile reflux method. Served as an anode material for SIBs, the Sn/SnO{sub 2}/PC nanocomposite delivers the primary discharge and charge capacities of 1148.1 and 303.0 mAh g{sup −1}, respectively. Meanwhile, it can preserve the discharge capacity approximately of 265.4 mAh g{sup −1} after 50 cycles, which is much higher than those of SnO{sub 2}/PC (138.5 mAh g{sup −1}) and PC (92.2 mAh g{sup −1}). Furthermore, the Sn/SnO{sub 2}/PC nanocomposite possesses better cycling stability with 77.8% capacity retention compared to that of SnO{sub 2}/PC (61.88%) over 50 cycles. Obviously, the Sn/SnO{sub 2}/PC composite with excellent electrochemical performance shows the great possibility of application in SIBs.

  6. Thermal performances of molten salt steam generator

    International Nuclear Information System (INIS)

    Yuan, Yibo; He, Canming; Lu, Jianfeng; Ding, Jing

    2016-01-01

    Highlights: • Thermal performances of molten salt steam generator were experimentally studied. • Overall heat transfer coefficient reached maximum with optimal molten salt flow rate. • Energy efficiency first rose and then decreased with salt flow rate and temperature. • Optimal molten salt flow rate and temperature existed for good thermal performance. • High inlet water temperature benefited steam generating rate and energy efficiency. - Abstract: Molten salt steam generator is the key technology for thermal energy conversion from high temperature molten salt to steam, and it is used in solar thermal power station and molten salt reactor. A shell and tube type molten salt steam generator was set up, and its thermal performance and heat transfer mechanism were studied. As a coupling heat transfer process, molten salt steam generation is mainly affected by molten salt convective heat transfer and boiling heat transfer, while its energy efficiency is also affected by the heat loss. As molten salt temperature increased, the energy efficiency first rose with the increase of heat flow absorbed by water/steam, and then slightly decreased for large heat loss as the absorbed heat flow still rising. At very high molten salt temperature, the absorbed heat flow decreased as boiling heat transfer coefficient dropping, and then the energy efficiency quickly dropped. As the inlet water temperature increased, the boiling region in the steam generator remarkably expanded, and then the steam generation rate and energy efficiency both rose with the overall heat transfer coefficient increasing. As the molten salt flow rate increased, the wall temperature rose and the boiling heat transfer coefficient first increased and then decreased according to the boiling curve, so the overall heat transfer coefficient first increased and then decreased, and then the steam generation rate and energy efficiency of steam generator both had maxima.

  7. Control structure design of a solid oxide fuel cell and a molten carbonate fuel cell integrated system: Top-down analysis

    International Nuclear Information System (INIS)

    Jienkulsawad, Prathak; Skogestad, Sigurd; Arpornwichanop, Amornchai

    2017-01-01

    Highlights: • Control structure of the combined fuel cell system is designed. • The design target is trade-off between power generation and carbon dioxide emission. • Constraints are considered according to fuel cell safe operation. • Eight variables have to be controlled to maximize profit. • Two control structures are purposed for three active constraint regions. - Abstract: The integrated system of a solid oxide fuel cell and molten carbonate fuel cell theoretically has very good potential for power generation with carbon dioxide utilization. However, the control strategy of such a system needs to be considered for efficient operation. In this paper, a control structure design for an integrated fuel cell system is performed based on economic optimization to select manipulated variables, controlled variables and control configurations. The objective (cost) function includes a carbon tax to get an optimal trade-off between power generation and carbon dioxide emission, and constraints include safe operation. This study focuses on the top-down economic analysis which is the first part of the design procedure. Three actively constrained regions as a function of the main disturbances, namely, the fuel and steam feed rates, are identified; each region represents different sets of active constraints. Under nominal operating conditions, the system operates in region I. However, operating the fuel cell system in region I and II can use the same structure, but in region III, a different control structure is required.

  8. Anodic Stripping Voltammetric Detection of Arsenic(III) at Platinum-Iron(III) Nanoparticle Modified Carbon Nanotube on Glassy Carbon Electrode

    International Nuclear Information System (INIS)

    Shin, Seung Hyun; Hong, Hun Gi

    2010-01-01

    The electrochemical detection of As(III) was investigated on a platinum-iron(III) nanoparticles modified multiwalled carbon nanotube on glassy carbon electrode(nanoPt-Fe(III)/MWCNT/GCE) in 0.1 M H 2 SO 4 . The nanoPt-Fe(III)/ MWCNT/GCE was prepared via continuous potential cycling in the range from .0.8 to 0.7 V (vs. Ag/AgCl), in 0.1 M KCl solution containing 0.9 mM K 2 PtCl 6 and 0.6 mM FeCl 3 . The Pt nanoparticles and iron oxide were co-electrodeposited into the MWCNT-Nafion composite film on GCE. The resulting electrode was examined by cyclic voltammetry (CV), scanning electron microscopy (SEM), and anodic stripping voltammetry (ASV). For the detection of As(III), the nanoPt-Fe(III)/MWCNT/GCE showed low detection limit of 10 nM (0.75 ppb) and high sensitivity of 4.76 μAμM -1 , while the World Health Organization's guideline value of arsenic for drinking water is 10 ppb. It is worth to note that the electrode presents no interference from copper ion, which is the most serious interfering species in arsenic detection

  9. In situ spectroscopy and spectroelectrochemistry of uranium in high-temperature alkali chloride molten salts.

    Science.gov (United States)

    Polovov, Ilya B; Volkovich, Vladimir A; Charnock, John M; Kralj, Brett; Lewin, Robert G; Kinoshita, Hajime; May, Iain; Sharrad, Clint A

    2008-09-01

    Soluble uranium chloride species, in the oxidation states of III+, IV+, V+, and VI+, have been chemically generated in high-temperature alkali chloride melts. These reactions were monitored by in situ electronic absorption spectroscopy. In situ X-ray absorption spectroscopy of uranium(VI) in a molten LiCl-KCl eutectic was used to determine the immediate coordination environment about the uranium. The dominant species in the melt was [UO 2Cl 4] (2-). Further analysis of the extended X-ray absorption fine structure data and Raman spectroscopy of the melts quenched back to room temperature indicated the possibility of ordering beyond the first coordination sphere of [UO 2Cl 4] (2-). The electrolytic generation of uranium(III) in a molten LiCl-KCl eutectic was also investigated. Anodic dissolution of uranium metal was found to be more efficient at producing uranium(III) in high-temperature melts than the cathodic reduction of uranium(IV). These high-temperature electrolytic processes were studied by in situ electronic absorption spectroelectrochemistry, and we have also developed in situ X-ray absorption spectroelectrochemistry techniques to probe both the uranium oxidation state and the uranium coordination environment in these melts.

  10. Ultrafine Sn nanoparticles embedded in shell of N-doped hollow carbon spheres as high rate anode for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Dou, Peng; Cao, Zhenzhen; Wang, Chao; Zheng, Jiao [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Xu, Xinhua, E-mail: xhxutju@gmail.com [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China)

    2017-05-15

    Highlights: • Dynamic covalent bond in polymeric nanoparticles is used to induce hollow Sn{sup 4+}-MOPs. • Ultrafine Sn nanoparticles uniformly embedded in shell of N-doped hollow carbon spheres is successfully synthesized by pyrolysis of the Sn{sup 4+}-MOPs precursor. • The composite exhibits superior cycle stability and rate capacity. - Abstract: A novel reversible interaction in polymeric nanoparticles is used to induce hollow Sn{sup 4+}-MOPs. Then ultrafine Sn nanoparticles uniformly embedded in shell of N-doped hollow carbon spheres is successfully synthesized by pyrolysis of the Sn{sup 4+}-MOPs precursor. In this architecture, the N-doped carbon shells can effectively avoid the direct exposure of embedded Sn nanoparticles to the electrolyte and efficiently accommodate the volume change of Sn nanoparticles. Furthermore, the hollow structure of carbon sphere can prevent Sn nanoparticles aggregation over repeated cycling and shorten the diffusion path of both electrons and ions. As a consequence, this N-doped hollow Sn/C anode delivers a reversible capacity of 606 mA h g{sup −1} at a current density of 0.2 A g{sup −1} after 250 cycles and a reversible capacity of 221 mA h g{sup −1} even at a much higher current density of 10 A g{sup −1}, which are much better than those of pure Sn nanoparticles. The desirable cyclic stability and rate capability were attributed to the unique architecture that provided fast pathway for electron transport and simultaneously solved the major issues of Sn-based anodes, such as pulverization, aggregation and loss of electrical contact.

  11. Three-Dimensional Porous Si and SiO2 with In Situ Decorated Carbon Nanotubes As Anode Materials for Li-ion Batteries.

    Science.gov (United States)

    Su, Junming; Zhao, Jiayue; Li, Liangyu; Zhang, Congcong; Chen, Chunguang; Huang, Tao; Yu, Aishui

    2017-05-31

    A high-capacity Si anode is always accompanied by very large volume expansion and structural collapse during the lithium-ion insertion/extraction process. To stabilize the structure of the Si anode, magnesium vapor thermal reduction has been used to synthesize porous Si and SiO 2 (pSS) particles, followed by in situ growth of carbon nanotubes (CNTs) in pSS pores through a chemical vapor deposition (CVD) process. Field-emission scanning electron microscopy and high-resolution transmission electron microscopy have shown that the final product (pSS/CNTs) possesses adequate void space intertwined by uniformly distributed CNTs and inactive silica in particle form. pSS/CNTs with such an elaborate structural design deliver improved electrochemical performance, with better coulombic efficiency (70% at the first cycle), cycling capability (1200 mAh g -1 at 0.5 A g -1 after 200 cycles), and rate capability (1984, 1654, 1385, 1072, and 800 mAh g -1 at current densities of 0.1, 0.2, 0.5, 1, and 2 A g -1 , respectively), compared to pSS and porous Si/CNTs. These merits of pSS/CNTs are attributed to the capability of void space to absorb the volume changes and that of the silica to confine the excessive lithiation expansion of the Si anode. In addition, CNTs have interwound the particles, leading to significant enhancement of electronic conductivity before and after Si-anode pulverization. This simple and scalable strategy makes it easy to expand the application to manufacturing other alloy anode materials.

  12. Production of low-silicon molten iron from high-silica hematite using biochar

    Institute of Scientific and Technical Information of China (English)

    Hui-qing Tang∗; Xiu-feng Fu; Yan-qi Qin; Shi-yu Zhao; Qing-guo Xue

    2017-01-01

    A new method of utilizing high-silica hematite to produce low-silicon molten iron was proposed.In this method, FASTMELT, which comprised direct reduction and melt separation processes, was applied, with highly reactive biochar as the reductant in the direct reduction stage.The proposed method was ex-perimentally investigated and the results show that the method is feasible.In the direct reduction stage, ore-char briquette could achieve a metallization rate of 84%-88% and residual carbon of 0.27-0.89 mass% at temperature of 1 373 K, biochar mixing ratio of 0.8-0.9, and reduction time of 15 min.Some silica particles remained embedded in the iron phase after the reduction.In the melting separation stage, molten iron with a carbon content of 0.02-0.03 mass% and silicon content of 0.02-0.18 mass% could be obtained from the metallic briquettes under the above-mentioned conditions; the iron recovery rate was 83%-91% and impurities in the obtained metal were negligible.

  13. An Amorphous Carbon Nitride Composite Derived from ZIF-8 as Anode Material for Sodium-Ion Batteries.

    Science.gov (United States)

    Fan, Jing-Min; Chen, Jia-Jia; Zhang, Qian; Chen, Bin-Bin; Zang, Jun; Zheng, Ming-Sen; Dong, Quan-Feng

    2015-06-08

    An composite comprising amorphous carbon nitride (ACN) and zinc oxide is derived from ZIF-8 by pyrolysis. The composite is a promising anode material for sodium-ion batteries. The nitrogen content of the ACN composite is as high as 20.4 %, and the bonding state of nitrogen is mostly pyridinic, as determined by X-ray photoelectron spectroscopy (XPS). The composite exhibits an excellent Na(+) storage performance with a reversible capacity of 430 mA h g(-1) and 146 mA h g(-1) at current densities of 83 mA g(-1) and 8.33 A g(-1) , respectively. A specific capacity of 175 mA h g(-1) was maintained after 2000 cycles at 1.67 A g(-1) , with only 0.016 % capacity degradation per cycle. Moreover, an accelerating rate calorimetry (ARC) test demonstrates the excellent thermal stability of the composite, with a low self heating rate and high onset temperature (210 °C). These results shows its promise as a candidate material for high-capacity, high-rate anodes for sodium-ion batteries. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Stannous sulfide/multi-walled carbon nanotube hybrids as high-performance anode materials of lithium-ion batteries

    International Nuclear Information System (INIS)

    Li, Shuankui; Zuo, Shiyong; Wu, Zhiguo; Liu, Ying; Zhuo, Renfu; Feng, Juanjuan; Yan, De; Wang, Jun; Yan, Pengxun

    2014-01-01

    A hybrid of multi-walled carbon nanotubes (MWCNTs) anchored with SnS nanosheets is synthesized through a simple solvothermal method for the first time. Interestingly, SnS can be controllably deposited onto the MWCNTs backbone in the shape of nanosheets or nanoparticles to form two types of SnS/MWCNTs hybrids, SnS NSs/MWCNTs and SnS NPs/MWCNTs. When evaluated as an anode material for lithium-ion batteries, the hybrids exhibit higher lithium storage capacities and better cycling performance compared to pure SnS. It is found that the SnS NSs/MWCNTs hybrid exhibits a large reversible capacity of 620mAhg −1 at a current of 100mAg −1 as an anode material for lithium-ion batteries, which is better than SnS NPs/MWCNTs. The improved performance may be attributed to the ultrathin nanosheet subunits possess short distance for Li + ions diffusion and large electrode-electrolyte contact area for high Li + ions flux across the interface. It is believed that the structural design of electrodes demonstrated in this work will have important implications on the fabrication of high-performance electrode materials for lithium-ion batteries

  15. Electrodeposition of some metals and niobium superconducting alloys from molten fluorides

    International Nuclear Information System (INIS)

    Cohen, U.

    1978-01-01

    The major goal of this thesis was to study the feasibility of electrodeposition from molten fluorides of the pure elements niobium, aluminium, tin, germanium and silicon, and the niboium superconducting intermetallic compounds with these elements, and to prepare and study films of these materials in the form of coherent and uniform coatings. Decomposition potential measurements with a gold anode were carried out on the alkali fluoride solvent and the fluoride salt solutions of niobium, aluminum, tin, and germanium to provide important initial thermodynamic data. Attempts to codeposit niobium and aluminum invariably failed, niobium being the exclusive deposit in all cases. Codeposition of niobium--tin alloys was demonstrated. Of the four intermetallic compounds of the niobium--germanium system, three were obtained as single-phase coatings. The superconducting compound (A15 phase) was not successfully electrodeposited in a single-phase form. It was obtained, however, in phase-mixture coatings. Application of alternating square wave pulses produced substantial changes in the morphology of niobium deposits. Silicon electrocrystallization epitaxy (ECE) was demonstrated for the first time. Uniform, coherent, and well adherent coatings of polycrystalline Si with a grain diameter of up to 40 to 50 μm were plated onto nonalloying metal substrates, such as silver and tungsten.These processes offer some attractive features for both integrated circuit technology and silicon solar cell fabrication. Aluminum, tin, and germanium were also electrodeposited from molten fluorides

  16. Sustainable design of high-performance microsized microbial fuel cell with carbon nanotube anode and air cathode

    KAUST Repository

    Mink, Justine E.

    2013-08-27

    Microbial fuel cells (MFCs) are a promising alternative energy source that both generates electricity and cleans water. Fueled by liquid wastes such as wastewater or industrial wastes, the microbial fuel cell converts waste into energy. Microsized MFCs are essentially miniature energy harvesters that can be used to power on-chip electronics, lab-on-a-chip devices, and/or sensors. As MFCs are a relatively new technology, microsized MFCs are also an important rapid testing platform for the comparison and introduction of new conditions or materials into macroscale MFCs, especially nanoscale materials that have high potential for enhanced power production. Here we report a 75 μL microsized MFC on silicon using CMOS-compatible processes and employ a novel nanomaterial with exceptional electrochemical properties, multiwalled carbon nanotubes (MWCNTs), as the on-chip anode. We used this device to compare the usage of the more commonly used but highly expensive anode material gold, as well as a more inexpensive substitute, nickel. This is the first anode material study done using the most sustainably designed microsized MFC to date, which utilizes ambient oxygen as the electron acceptor with an air cathode instead of the chemical ferricyanide and without a membrane. Ferricyanide is unsustainable, as the chemical must be continuously refilled, while using oxygen, naturally found in air, makes the device mobile and is a key step in commercializing this for portable technology such as lab-on-a-chip for point-of-care diagnostics. At 880 mA/m2 and 19 mW/m2 the MWCNT anode outperformed the others in both current and power densities with between 6 and 20 times better performance. All devices were run for over 15 days, indicating a stable and high-endurance energy harvester already capable of producing enough power for ultra-low-power electronics and able to consistently power them over time. © 2013 American Chemical Society.

  17. Monodisperse SnO2 nanocrystals functionalized multiwalled carbon nanotubes for large rate and long lifespan anode materials in lithium ion batteries

    International Nuclear Information System (INIS)

    Song, Huawei; Li, Na; Cui, Hao; Wang, Chengxin

    2014-01-01

    A facile way towards high rate and long lifespan anode materials based on SnO 2 and commercial multiwalled carbon nanotubes (MWCNTs) is readily achieved through a combination of activation and hydrothermal treatment. The former endows the MWCNTs with abundant hydrophilic radicals, while the latter guarantees intimate connection between SnO 2 and MWCNTs; eventually, monodisperse SnO 2 nanocrystals ca. 3 nm are firmly anchored on the MWCNTs without agglomeration. When used for lithium ion batteries (LIBs) anodes, the hybrid composite exhibits excellent cycling capability with high reversible capacity about 700 mAh g −1 (based on total weight of the composite) for 150 cycles at 0.1 A g −1 superior to both components involved. Besides large rates of 5 A g −1 with recoverable initial reversible capacity, it also last for more than 1000 cycles with little capacity decay, outperforming most SnO 2 based carbon nanotubes composites (SnO 2 /CNTs) so far. Insights into the electrochemical processes reveal the hybrid composite exhibits enhanced redox capacitance and interfacial capacitance in comparison with SnO 2 nanocrystals which indicate the perfect interfaces and robust structure of the hybrid composite

  18. Carbon nanofibers (CNFs) supported cobalt- nickel sulfide (CoNi2S4) nanoparticles hybrid anode for high performance lithium ion capacitor.

    Science.gov (United States)

    Jagadale, Ajay; Zhou, Xuan; Blaisdell, Douglas; Yang, Sen

    2018-01-25

    Lithium ion capacitors possess an ability to bridge the gap between lithium ion battery and supercapacitor. The main concern of fabricating lithium ion capacitors is poor rate capability and cyclic stability of the anode material which uses sluggish faradaic reactions to store an electric charge. Herein, we have fabricated high performance hybrid anode material based on carbon nanofibers (CNFs) and cobalt-nickel sulfide (CoNi 2 S 4 ) nanoparticles via simple electrospinning and electrodeposition methods. Porous and high conducting CNF@CoNi 2 S 4 electrode acts as an expressway network for electronic and ionic diffusion during charging-discharging processes. The effect of anode to cathode mass ratio on the performance has been studied by fabricating lithium ion capacitors with different mass ratios. The surface controlled contribution of CNF@CoNi 2 S 4 electrode was 73% which demonstrates its excellent rate capability. Lithium ion capacitor fabricated with CNF@CoNi 2 S 4 to AC mass ratio of 1:2.6 showed excellent energy density of 85.4 Wh kg -1 with the power density of 150 W kg -1 . Also, even at the high power density of 15 kW kg -1 , the cell provided the energy density of 35 Wh kg -1 . This work offers a new strategy for designing high-performance hybrid anode with the combination of simple and cost effective approaches.

  19. Determination of picomolar silver concentrations by differential pulse anodic stripping voltammetry at a carbon paste electrode modified with phenylthiourea-functionalized high ordered nanoporous silica gel

    International Nuclear Information System (INIS)

    Javanbakht, Mehran; Divsar, Faten; Badiei, Alireza; Fatollahi, Fatemeh; Khaniani, Yeganeh; Ganjali, Mohammad Reza; Norouzi, Parviz; Chaloosi, Marzieh; Ziarani, Ghodsi Mohammadi

    2009-01-01

    This study introduces the design of an anodic stripping voltammetric (ASV) method for the silver ion determination at a carbon paste electrode (CPE), chemically modified with phenylthiourea-nanoporous silica gel (Tu-SBA-15-CPE). The electroanalytical pro includes two steps: preconcentration of metal ions at an electrode surface, followed by quantification of the accumulated species by differential pulse anodic stripping voltammetric methods. Factors affecting the performance of the anodic stripping were investigated, including the modifier quantity in the paste, the electrolyte concentrations, the solution pH and the accumulation potential or time. The most sensitive and reliable electrode contained 10% Tu-SBA-15 and 90% carbon paste. The accumulation potential and time were set at, -200 mV and 300 s, respectively, and the scan rate at 50 mV s -1 in the scan range of -200 to 700 mV. The resulting electrode demonstrated a linear response over range of silver ion concentration of 8.0-80 pmol/L with detection limit (S/N = 3) of 5 pmol/L. The prepared electrodes were used for the silver determination in sea and tap water samples and very good recovery results were obtained. The accuracy was assessed through recovery experiments and independent analysis by graphite furnace atomic absorption spectrometry.

  20. Determination of picomolar silver concentrations by differential pulse anodic stripping voltammetry at a carbon paste electrode modified with phenylthiourea-functionalized high ordered nanoporous silica gel

    Energy Technology Data Exchange (ETDEWEB)

    Javanbakht, Mehran [Department of Chemistry, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Nano Science and Technology Research Center, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of)], E-mail: mehranjavanbakht@gmail.com; Divsar, Faten [Department of Chemistry, University of Tarbiat Moallem, Tehran (Iran, Islamic Republic of); Badiei, Alireza [School of Chemistry, University College of Science, University of Tehran, Tehran (Iran, Islamic Republic of); Fatollahi, Fatemeh [Department of Chemistry, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Khaniani, Yeganeh [School of Chemistry, University College of Science, University of Tehran, Tehran (Iran, Islamic Republic of); Ganjali, Mohammad Reza; Norouzi, Parviz [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Chaloosi, Marzieh [Department of Chemistry, University of Tarbiat Moallem, Tehran (Iran, Islamic Republic of); Ziarani, Ghodsi Mohammadi [Department of Chemistry, University of Alzahra, Tehran (Iran, Islamic Republic of)

    2009-09-30

    This study introduces the design of an anodic stripping voltammetric (ASV) method for the silver ion determination at a carbon paste electrode (CPE), chemically modified with phenylthiourea-nanoporous silica gel (Tu-SBA-15-CPE). The electroanalytical pro includes two steps: preconcentration of metal ions at an electrode surface, followed by quantification of the accumulated species by differential pulse anodic stripping voltammetric methods. Factors affecting the performance of the anodic stripping were investigated, including the modifier quantity in the paste, the electrolyte concentrations, the solution pH and the accumulation potential or time. The most sensitive and reliable electrode contained 10% Tu-SBA-15 and 90% carbon paste. The accumulation potential and time were set at, -200 mV and 300 s, respectively, and the scan rate at 50 mV s{sup -1} in the scan range of -200 to 700 mV. The resulting electrode demonstrated a linear response over range of silver ion concentration of 8.0-80 pmol/L with detection limit (S/N = 3) of 5 pmol/L. The prepared electrodes were used for the silver determination in sea and tap water samples and very good recovery results were obtained. The accuracy was assessed through recovery experiments and independent analysis by graphite furnace atomic absorption spectrometry.