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Sample records for cathode supported electrolytes

  1. LOW TEMPERATURE CATHODE SUPPORTED ELECTROLYTES

    Energy Technology Data Exchange (ETDEWEB)

    Harlan U. Anderson; Fatih Dogan; Vladimir Petrovsky

    2002-03-31

    This project has three main goals: Thin Films Studies, Preparation of Graded Porous Substrates and Basic Electrical Characterization and testing of Planar Single Cells. This period has continued to address the problem of making dense 1/2 to 5 {micro}m thick dense layers on porous substrates (the cathode LSM). Our current status is that we are making structures of 2-5 cm{sup 2} in area, which consist of either dense YSZ or CGO infiltrated into a 2-5 {micro}m thick 50% porous layer made of either nanoncrystalline CGO or YSZ powder. This composite structure coats a macroporous cathode or anode; which serves as the structural element of the bi-layer structure. These structures are being tested as SOFC elements. A number of structures have been evaluated both as symmetrical and as button cell configuration. Results of this testing indicates that the cathodes contribute the most to cell losses for temperatures below 750 C. In this investigation different cathode materials were studied using impedance spectroscopy of symmetric cells and IV characteristics of anode supported fuel cells. Cathode materials studied included La{sub 0.8}Sr{sub 0.2}Co{sub 0.2}Fe{sub 0.8}O{sub 3} (LSCF), La{sub 0.7}Sr{sub 0.2}MnO{sub 3} (LSM), Pr{sub 0.8}Sr{sub 0.2}Fe{sub 0.8}O{sub 3} (PSCF), Sm{sub 0.8}Sr{sub 0.2}Co{sub 0.2}Fe{sub 0.8}O{sub 3} (SSCF), and Yb{sub .8}Sr{sub 0.2}Co{sub 0.2}Fe{sub 0.8}O{sub 3} (SSCF). A new technique for filtering the Fourier transform of impedance data was used to increase the sensitivity of impedance analysis. By creating a filter specifically for impedance spectroscopy the resolution was increased. The filter was tailored to look for specific circuit elements like R//C, Warburg, or constant phase elements. As many as four peaks can be resolved using the filtering technique on symmetric cells. It may be possible to relate the different peaks to material parameters, like the oxygen exchange coefficient. The cathode grouped in order from lowest to highest ASR is

  2. LOW TEMPERATURE CATHODE SUPPORTED ELECTROLYTES

    Energy Technology Data Exchange (ETDEWEB)

    Harlan U. Anderson

    2000-03-31

    . However, they have the potential of being useful as an interface on the anode side of the electrolyte. NexTech has focused much of its effort during the past few months on establishing tape casting methods for porous LSM substrates. This work, performed under a separate DOE-funded program, involved tape casting formulations comprising LSM powders with bi-modal particle size distributions and fugitive pore forming additives. Sintered LSM substrates with porosities in the 30 to 40 vol% range, and pore sizes of 10 {approx} 20 microns have been prepared. In addition, tape casting formulations involving composite mixtures of LSM and Sm-doped ceria (SDC) have been evaluated. The LSM/SDC cathode substrates are expected to provide better performance at low temperatures. Characterization of these materials is currently underway.

  3. LOW TEMPERATURE CATHODE SUPPORTED ELECTROLYTES

    Energy Technology Data Exchange (ETDEWEB)

    Harlan U. Anderson; Wayne Huebner; Igor Kosacki

    2001-09-30

    This project has three main goals: Thin Films Studies, Preparation of Graded Porous Substrates and Basic Electrical Characterization and testing of Planar Single Cells. In this portion of study we have focused on producing YSZ films on porous LSM substrates. When using the polymer precursor there are a number of obstacles to overcome in order to form dense electrolyte layers on porous substrates (cathode or anode). Probably the most difficult problems are: (1) Extreme penetration of the polymer into the substrate must be prevented. (2) Shrinkage cracking must be avoided. (3) Film thickness in the 1 to 5{micro}m range must be achieved. We have demonstrated that cracking due to shrinkage involved during the elimination of solvents and organic matter and densification of the remaining oxide is not a problem as long as the resulting oxide film is < {approx} 0.15 {micro}m in thickness. We have also shown that we can make thicker films by making multiple depositions if the substrate is smooth (roughness {le} 0.1 {micro}m) and contains no surface pores > 0.2 {micro}m. The penetration of the polymer into the porous substrate can be minimized by increasing the viscosity of the polymer and reducing the largest pore at the surface of the substrate to {le} 0.2 {micro}m. We have shown that this can be done, but we have also shown that it is difficult to make dense films that are defect free with areas > 1 cm{sup 2}. This is because of the roughness of the substrate and the difficulty in making a substrate which does not have surface voids > 0.2 {micro}m. Thus the process works well for dense, smooth substrates for films < 1 {micro}m thick, but is difficult to apply to rough, porous surfaces and to make film thickness > 1 {micro}m. As a result of these problems, we have been addressing the issue of how to make dense films in the thickness range of 1 to 5 {micro}m on sintered porous substrates without introducing cracks and holes due to shrinkage and surface voids? These

  4. Enhanced stability of multilayer graphene-supported catalysts for polymer electrolyte membrane fuel cell cathodes

    Science.gov (United States)

    Marinkas, A.; Hempelmann, R.; Heinzel, A.; Peinecke, V.; Radev, I.; Natter, H.

    2015-11-01

    One of the biggest challenges in the field of polymer electrolyte membrane fuel cells (PEMFC) is to enhance the lifetime and the long-term stability of PEMFC electrodes, especially of cathodes, furthermore, to reduce their platinum loading, which could lead to a cost reduction for efficient PEMFCs. These demands could be achieved with a new catalyst support architecture consisting of a composite of carbon structures with significant different morphologies. A highly porous cathode catalyst support layer is prepared by addition of various carbon types (carbon black particles, multi-walled carbon nanotubes (MWCNT)) to multilayer graphene (MLG). The reported optimized cathodes shows extremely high durability and similar performance to commercial standard cathodes but with 89% lower Pt loading. The accelerated aging protocol (AAP) on the membrane electrode assemblies (MEA) shows that the presence of MLG increases drastically the durability and the Pt-extended electrochemical surface area (ECSA). In fact, after the AAP slightly enhanced performance can be observed for the MLG-containing cathodes instead of a performance loss, which is typical for the commercial carbon-based cathodes. Furthermore, the presence of MLG drastically decreases the ECSA loss rate. The MLG-containing cathodes show up to 6.8 times higher mass-normalized Pt-extended ECSA compared to the commercial standard systems.

  5. Optimization of Pore Structure of Cathodic Carbon Supports for Solvate Ionic Liquid Electrolytes Based Lithium-Sulfur Batteries.

    Science.gov (United States)

    Zhang, Shiguo; Ikoma, Ai; Li, Zhe; Ueno, Kazuhide; Ma, Xiaofeng; Dokko, Kaoru; Watanabe, Masayoshi

    2016-10-04

    Lithium-sulfur (Li-S) batteries are a promising energy-storage technology owing to their high theoretical capacity and energy density. However, their practical application remains a challenge because of the serve shuttle effect caused by the dissolution of polysulfides in common organic electrolytes. Polysulfide-insoluble electrolytes, such as solvate ionic liquids (ILs), have recently emerged as alternative candidates and shown great potential in suppressing the shuttle effect and improving the cycle stability of Li-S batteries. Redox electrochemical reactions in polysulfide-insoluble electrolytes occur via a solid-state process at the interphase between the electrolyte and the composite cathode; therefore, creating an appropriate interface between sulfur and a carbon support is of great importance. Nevertheless, the porous carbon supports established for conventional organic electrolytes may not be suitable for polysulfide-insoluble electrolytes. In this work, we investigated the effect of the porous structure of carbon materials on the Li-S battery performance in polysulfide-insoluble electrolytes using solvate ILs as a model electrolyte. We determined that the pore volume (rather than the surface area) exerts a major influence on the discharge capacity of S composite cathodes. In particular, inverse opal carbons with three-dimensionally ordered interconnected macropores and a large pore volume deliver the highest discharge capacity. The battery performance in both polysulfide-soluble electrolytes and solvate ILs was used to study the effect of electrolytes. We propose a plausible mechanism to explain the different porous structure requirements in polysulfide-soluble and polysulfide-insoluble electrolytes.

  6. Anode- electrolyte- cathode sets of unitary SOFC with electro-catalysts deposited on previously sintered porous support

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, L.F.V.; Souza, F.M.B.; Fiuza, R.P.; Alencar, M.G.F.; Silva, M.A.; Boaventura, J.S. [Chemistry Inst., Salvador (Brazil). Dept. of Physical Chemistry

    2009-07-01

    The solid oxide fuel cell (SOFC) can be used in a broad range of applications. YSZ (yttria stabilized zirconia) and GDC (gadolinia doped ceria) are components of the anode/electrolyte set and LSM (manganite of strontium and lanthanum) ink are components of the cathode. In this study, different combinations of sodium bicarbonate, graphite and citric acid were used to form the electrocatalyst on nickel and iron. After sintering, the set was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and surface area by BET. The pellets had good porosity and the anode-cathode-electrolyte interfaces had good inter-layer adherence. The catalyst was evenly dispersed on the support. The final porous structure did not have any surface area loss compared to the original powder. The mixed agents were found to be good pore formatting agents, with characteristics that were favourable for achieving good sets of anode-cathode-electrolytes. The final structure had good pore distribution and formation. The anode had good surface area and good tack from the interface anode/electrolyte.

  7. Multichannel discharge between jet electrolyte cathode and jet electrolyte anode

    NARCIS (Netherlands)

    Shakirova, E. F.; Gaitsin, Al. F.; Son, E. E.

    2011-01-01

    We present the results of an experimental study of multichannel discharge between a jet electrolyte cathode and jet electrolyte anode within a wide range of parameters. We pioneer the reveal of the burning particularities and characteristics of multichannel discharge with jet electrolyte and droplet

  8. Load cycle durability of a graphitized carbon black-supported platinum catalyst in polymer electrolyte fuel cell cathodes

    Science.gov (United States)

    Takei, Chikara; Kakinuma, Katsuyoshi; Kawashima, Kazuhito; Tashiro, Keisuke; Watanabe, Masahiro; Uchida, Makoto

    2016-08-01

    We focus on Pt degradation occurring during fuel cell vehicle (FCV) combined drive cycles involving load and open circuit voltage (OCV) just after startup and during idling. Load cycle durability is evaluated as a function of OCV/load holding time, load rate and relative humidity (RH) with a graphitized carbon black-supported platinum catalyst (Pt/GCB) in the cathode. The degradation of Pt/GCB is suppressed for shorter OCV holding times, lower load rates and lower RH. Scanning ion microscopy (SIM) images of membrane cross-sections indicate that the amount of Pt deposited in the membrane decreases during drive cycles involving load with short OCV holding times. Investigations of the Pt distribution in the cathode catalyst layer (CL) by using scanning TEM-EDX show that the dissolution of Pt is suppressed on the membrane side in the CL. The Pt dissolution is accelerated by the high Pt oxidation due to the long OCV holding time. A load cycle with both long OCV holding time and low load inhibits the Pt2+ migration into the membrane but accelerates the Pt particle growth due to electrochemical Ostwald ripening; meanwhile, a load cycle with long OCV holding time at lower RH prevents both the Pt dissolution and particle growth.

  9. Model study on the stability of carbon support materials under polymer electrolyte fuel cell cathode operation conditions

    Energy Technology Data Exchange (ETDEWEB)

    Colmenares, L.C.; Jusys, Z.; Behm, R.J. [Institute of Surface Chemistry and Catalysis, Ulm University, D-89069 Ulm (Germany); Wurth, A. [TS-IM-IM-CB Inorganic Materials, Evonik Degussa GmbH, D-50997 Cologne (Germany)

    2009-05-01

    The electrochemical oxidation and corrosion resistance of differently prepared and post-treated (graphitization, surface oxidation) carbon support materials, whose surface area and composition were characterized by adsorption measurements and X-ray photoelectron spectroscopy, were investigated in model studies performed under fuel cell cathode relevant potential conditions. These included also the abnormal cathode potentials (up to 1.5 V{sub RHE}) occurring during start-up and shut-down procedures. Reversible surface oxidation, leading, e.g., to the formation of quinones/hydroquinones, and irreversible oxidation to CO{sub 2} were discriminated by combining electrochemical and on-line mass spectrometry measurements. Oxygenated surface carbon species were found to affect the surface area normalized electrooxidation activity much more than the surface area and porosity of the material, with graphitized carbon with low porosity and low oxygen surface content being most resistant towards reversible oxidation and towards irreversible oxidation at high potentials. Trapped CO{sub 2}, formed upon carbon oxidation at high potentials, is proposed to be at least partly responsible for CO{sub 2} release at low potentials, below the standard potential for electrochemical carbon oxidation. (author)

  10. Comparison between fixed and fluidized bed cathodes and effect of supporting electrolyte in electrochemical removal of copper ion from dilute solutions

    Directory of Open Access Journals (Sweden)

    I.A. Khattab

    2014-03-01

    Experimental study of the role of the supporting electrolyte in electrolytic cells confirmed that, type and concentration of supporting electrolyte have a remarkable effect on the two aforementioned parameters as well as the rate of removal. Using of NaCl showed better results than Na2SO4.

  11. Interactions of alkali metals and electrolyte with cathode carbons

    Energy Technology Data Exchange (ETDEWEB)

    Naas, Tyke

    1997-12-31

    The Hall-Heroult process for electrolytic reduction of alumina has been the only commercial process for production of primary aluminium. The process runs at high temperature and it is important to minimize the energy consumption. To save energy it is desirable to reduce the operating temperature. This can be achieved by adding suitable additives such as LiF or KF to the cryolitic electrolyte. This may conflict with the objective of extending the lifetime of the cathode linings of the cell as much as possible. The thesis investigates this possibility and the nature of the interactions involved. It supports the hypothesis that LiF-additions to the Hall-Heroult cell electrolyte is beneficial to the carbon cathode performance because the diminished sodium activity reduces the sodium induced stresses during the initial period of electrolysis. The use of KF as an additive is more dangerous, but the results indicate that additions up to 5% KF may be tolerated in acidic melts with semigraphitic or graphitic cathodes with little risk of cathode problems. 153 refs., 94 figs., 30 tabs.

  12. High current density cathode for electrorefining in molten electrolyte

    Science.gov (United States)

    Li, Shelly X.

    2010-06-29

    A high current density cathode for electrorefining in a molten electrolyte for the continuous production and collection of loose dendritic or powdery deposits. The high current density cathode eliminates the requirement for mechanical scraping and electrochemical stripping of the deposits from the cathode in an anode/cathode module. The high current density cathode comprises a perforated electrical insulated material coating such that the current density is up to 3 A/cm.sup.2.

  13. Manufacturing of Electrolyte and Cathode Layers SOFC Using Atmospheric Spraying Method and Its Characterization

    Directory of Open Access Journals (Sweden)

    S. Sulistyo

    2012-12-01

    Full Text Available The use of Solid Oxide Fuel Cell (SOFC has created various interest in many parties, due to its capability to convert gases into electricity. The main requirement of SOFC cell components is to be produced as thin as possible to minimize the losses of electrical resistance, as well as able to support internal and external loads. This paper discusses the procedure of making a thin electrolyte layer, as well as a porous thin layer cathode using atmospheric spraying technique. The procedure of spraying was in room temperature with the process of sintering at temperature of 13500 C held for 3 hours. The SOFC characterization of electrolyte and cathode microstructure was determined by using the SEM, FESEM, XRD and impedance spectroscopy, to measure the impedance of SOFC cells. The results show that the thickness of thin layer electrolyte and porous cathode obtained of about 20 µm and 4 µm, respectively. Also the SOFC cell impedance was measured of 2.3726 x 106 Ω at room temperature. The finding also demonstrated that although the materials (anode, cathode and electrolyte possess different coefficient thermal expansion, there was no evidence of flaking layers which seen the materials remain intact. Thus, the atmospheric spraying method can offer an alternative method to manufacturing of SOFC thin layer electrolyte and cathode. [Key words: SOFC; spraying method; electrolyte; cathode

  14. Microstructural studies on degradation of interface between LSM–YSZ cathode and YSZ electrolyte in SOFCs

    DEFF Research Database (Denmark)

    Liu, Yi-Lin; Hagen, Anke; Barfod, Rasmus;

    2009-01-01

    The changes in the cathode/electrolyte interface microstructure have been studied on anode-supported technological solid oxide fuel cells (SOFCs) that were subjected to long-term (1500 h) testing at 750 °C under high electrical loading (a current density of 0.75 A/cm2). These cells exhibit...... different cathode degradation rates depending on, among others, the composition of the cathode gas, being significantly smaller in oxygen than in air. FE-SEM and high resolution analytical TEM were applied for characterization of the interface on a submicron- and nano-scale. The interface degradation has...

  15. The Impact of Strong Cathodic Polarization on SOC Electrolyte Materials

    DEFF Research Database (Denmark)

    Kreka, Kosova; Hansen, Karin Vels; Jacobsen, Torben

    2016-01-01

    of impurities at the grain boundaries, electrode poisoning, delamination or cracks of the electrolyte etc., have been observed in cells operated at such conditions, lowering the lifetime of the cell1,2. High polarizations are observed at the electrolyte/cathode interface of an electrolysis cell operated at high...... current density. In case of a cell voltage above 1.6 V, p-type and n-type electronic conductivity are often observed at the anode and cathode respectively3. Hence, a considerable part of the current is lost as leakage through the electrolyte, thus lowering the efficiency of the cell considerably.......One of the most promising reversible energy conversion/storage technologies is that of Solid Oxide Fuel/Electrolysis Cells (SOFC/SOEC, collectively termed SOC). Long term durability is typically required for such devises to become economically feasible, hence considerable amount of work has...

  16. Electrolyte and Cathode Degradation Mechanisms in Lithium Ion Batteries

    Science.gov (United States)

    Tebbe, Jonathon

    Lithium ion battery technologies suffer from limitations in performance, such as capacity fading, due in part to degradation of the cathode and electrolyte materials. Quantum chemical simulations were employed to investigate the reactions leading to degradation of LiCoO2 cathodes and the electrolyte molecules. Formation of HF in the electrolyte resulting from reaction between PF5 and H2O impurities was first investigated. This research predicts HF is produced as a result of PF5 complexing with H2O, then reacting through ligand exchange to form HF and PF4OH with an activation barrier of 1.18 eV and reaction enthalpy of 0.15 eV. HF undergoes dissociative adsorption at that the (101¯4) surface of LiCoO2 without a barrier, leading to formation of LiF-Li+ precipitates and H 2O on the surface with a reaction energy of -2.41 eV. The formation of H2O is of particular concern because H2O drives further formation of HF in the electrolyte, resulting in an autocatalytic cycle of degradation. These findings indicate that HF initially occurs in low concentrations rapidly increases due to H2O generation upon HF attack. Reduction in capacity fading is observed in alumina ALD coated LiCoO2 cathodes and we have investigated a monolayer alumina coating on the LiCoO2 (101¯4) surface to identify the mechanism by which the alumina coating protects the cathode surface. We have found that HF will preferentially dissociate at the alumina coating with a reaction energy of -2.84 eV and without any resolvable barrier to dissociation. Additionally, our calculations predict that H2O does not form as a result of HF dissociation at the alumina monolayer; instead HF dissociation produces neighboring hydroxyl sites on the alumina surface. Consequently, the alumina coating prevents the autocatalytic degradation of the cathode by sequestering HF impurities in the alumina film. Finally, we found that Lewis acid-base complexation between ethylene carbonate (EC) electrolyte molecules and PF5 or the Li

  17. Electrochemical performances of BSCF cathode materials for composite electrolyte LTSOFC

    Energy Technology Data Exchange (ETDEWEB)

    Sun, X.L.; Li, S.; Sun, J.C. [Dalian Maritime Univ., Dalian (China). Inst. of Materials and Technology; Zhu, B. [Royal Inst. of Technology, Stockholm (Sweden). Dept. of Chemical Engineering]|[Dalian Maritime Univ., Dalian (China). Inst. of Materials and Technology

    2006-07-01

    The high temperature of solid oxide fuel cells (SOFCs) places high demands on the electrolytes and cathode materials used within them. A reduction in the operating temperatures of the SOFC may lead to improvements in sealing and corrosion problems and improve their long-term stability. However, performance of the SOFC may be negatively impacted due to an unavoidable increase in the oxygen reduction reaction in the cathode. This study investigated the use of BSCF on low temperature SOFCs. In an experiment, BSCF precursor powders were prepared using the sol-gel method. Cell assembly and tests were performed from the cell of a nickel and samaria-doped ceria carbonate/BSCF-Ag. The perovskite structure of the BSCF was characterized by X-ray diffraction. Results showed that the powder could be crystallized well after calcination. The morphology of the BSFC powder from a scanning electron microscopy (SEM) analysis was demonstrated. Some agglomerates were observed. A characterization of the fuel cell showed that the open circuit voltage was higher when the temperature decreased. Maximum power density was 452.6 mW/cm{sup 2} and 540.1 mW/cm{sup 2}. Short circuit currents of 1619 mA/cm{sup 2} and 1604 mA/cm{sup 2} were obtained at 450 degrees C and 500 degrees C respectively. The maximum power density of the fuel cell increased with increases in temperature. It was concluded that the power density of the fuel cell using the BSCF cathode was satisfactorily high for low temperature SOFCs. Further research is needed to improve the fuel cell performance when thinner electrolytes are used. 4 refs., 3 figs.

  18. New liquid cathode electrolytes in high rate cells

    Science.gov (United States)

    Bailey, Jean W.; Kalisz, David W.; Blomgren, George E.

    1990-03-01

    The power limitations of liquid oxyhalide batteries were explored by examining the physical and electrical properties of new electrolytes. Conductivity, kinematic viscosity, and specific gravity of electrolytes were measured inside a specially adapted argon filled drybox. Liquid cathode oxyhalide electrolytes designed to enhance power density were tested first in demountable test cells and then, the most promising, in hermetically sealed high rate F size jellyroll cells. For F cells, the capacity on constant current discharge was measured at 3.5 and 12.5 mA/sq cm for fresh cells at 21 C and at 3.5 mA/sq cm for cells stored 4 weeks at 54 C then discharged at -30 C. An optimized cell design with thicker electrodes was developed for testing electrolytes with higher conductivity than LiAlCl4-SOCl2. The best capacity at 2A was achieved with LiGaCl4-SOCl2 or LiAlCl4-SOCl2. The best capacity at 7A was achieved with LiGaCl4-SOCl2. LiGaCl4 in SOCl2 was found to discharge at higher temperatures than LiAlCl4 in SOCl2. Imidazolium, aralkylammonium, and sulfonium chlorides were found to have high solubility and conductivity in thionyl chloride, but lithium was found to be passive in contact with these solutions and most metals corroded excessively. These salts mixed with aluminum chloride were much less aggressive and when mixed with lithium salts in addition gave high conductivity and test cell capacities.

  19. Effect of cathode and electrolyte transport properties on chromium poisoning in solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Fergus, Jeffrey W. [Materials Research and Education Center, 275 Wilmore Laboratories, Auburn University, Auburn, AL 36849 (United States)

    2007-11-15

    A major degradation mechanism in solid oxide fuel cells (SOFCs) is poisoning of the cathode by chromium from volatilization of the interconnect material. The chromium deposition has been attributed to both chemical and electrochemical mechanisms. For an electrochemical reaction, deposition can occur only where both ions and electrons are available, which, for a purely ionic conducting electrolyte and a purely electronic conducting cathode, can occur only at the three-phase gas-electrolyte-electrode interface. However, the introduction of ionic conductivity into the cathode or electronic conductivity into the electrolyte can allow deposition to occur away from this three-phase interface, and thus alter its effect on the fuel cell performance. In this paper, the chromium poisoning of SOFC cathodes is reviewed, with a focus on the effects of the transport properties of the cathode and electrolyte materials. (author)

  20. A new composite cathode for intermediate temperature solid oxide fuel cells with zirconia-based electrolytes

    Science.gov (United States)

    Zhang, Cuijuan; Huang, Kevin

    2017-02-01

    Improving the electrocatalytic activity of electrode materials is vitally important to achieve practically meaningful performance for intermediate temperature solid oxide fuel cells (IT-SOFCs). The present work develops a composite cathode consisting of an electronic conductor Sr-doped LaMnO3 (LSM) and an ionic conductor Y- and Ce- co-doped Bi2O3 (BYC7). BYC7 is an excellent oxide-ion conductor, exhibiting a high and stable ionic conductivity of 0.008 S cm-1 at 500 °C. The polarization resistance of LSM-BYC7 cathode in a symmetrical cell with doped ZrO2 as electrolyte varies from 5.76 at 500 °C to 0.25 Ω cm2 at 650 °C. The surface diffusion and charge transfer at the triple phase boundaries are the rate determining steps based on the dependence of polarization resistance on partial pressure of oxygen. The maximum power density of a ZrO2-based anode-supported cell with LSM-BYC7 composite cathode is 56.4, 154.6, 327.9, and 451.0 mW cm-2 at 500, 550, 600, and 650 °C respectively. AC impedance analysis reveals that the performance of IT-SOFC prepared in this study is actually limited by the anode, not by LSM-BYC7 cathode.

  1. Anode Simulation and Cathode Design for Electrolytic Dressing of Diamond Profile Wheel

    Institute of Scientific and Technical Information of China (English)

    ZOU Feng; YU Aibing; TAN Yefa

    2005-01-01

    The design methods of anode and cathode are proposed for precision profile grinding. Based on the electrolytic machining theory, electrolytic equilibrium condition and Faraday′s law of electrolysis are applied to establishing the mathematical model of profile diamond dressing process-es. A finite element method (FEM) program is developed to solve the inverse boundary problem of Laplace′s equation. Desired anode contour or cathode shape is determined by computing the distribution of electric potential layer by layer. Electrolytic machining experiment is carried out to verify the simulated anode shape. The research result shows that shape deviation between designed cathode and profile wheel increases with the value of angle between feed rate and the normal to anode surface. The shape of simulated anode is consistent with the contour of metal-bonded diamond profile wheel for a given cathode. Based on the anode contour, cathode shape can also be designed accurately.

  2. Development of electrolyte-supported intermediate-temperature single-chamber solid oxide fuel cells using Ln 0.7Sr 0.3Fe 0.8Co 0.2O 3- δ (Ln = Pr, La, Gd) cathodes

    Science.gov (United States)

    Ruiz de Larramendi, I.; Lamas, D. G.; Cabezas, M. D.; Ruiz de Larramendi, J. I.; Walsöe de Reca, N. E.; Rojo, T.

    Iron-cobalt-based perovskite oxides with general formula Ln 0.7Sr 0.3Fe 0.8Co 0.2O 3- δ (where Ln = La, Pr and Gd) have been investigated for their application as intermediate-temperature cathodes in solid oxide fuel cells (SOFCs). Powdered samples of these materials were synthesized by a novel gel combustion process and then characterized by X-ray powder diffraction (XPD) and scanning electron microscopy (SEM). XPD patterns were satisfactorily indexed with an orthorhombic GdFeO 3-type structure and, for all samples, a mean particle size of less than 1 μm was estimated from the SEM data. Experimental single-chamber SOFCs using with these materials as cathodes and NiO-SDC (samaria-doped ceria) and SDC as anode and electrolyte, respectively, were evaluated at 600 °C in a methane/oxygen mixtures. Peak power densities of 65.4, 48.7 and 46.2 mW cm -2 were obtained for Ag|Ln 0.7Sr 0.3Fe 0.8Co 0.2O 3- δ|SDC|NiO-SDC|Pt cells with Ln = Pr, La and Gd, respectively. The relatively high power density obtained for the Pr compound shows that it could be an interesting material for cathode of single-chamber SOFCs.

  3. In Situ Engineering of the Electrode-Electrolyte Interface for Stabilized Overlithiated Cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Tyler [Department of Mechanical Engineering, University of Colorado at Boulder, Boulder CO 80309 USA; SiILion, Inc., Broomfield CO 80020 USA; Piper, Daniela Molina [SiILion, Inc., Broomfield CO 80020 USA; Sun, Huaxing [Department of Chemistry, University of Colorado at Boulder, Boulder CO 80309 USA; Porcelli, Timothy [Department of Chemistry, University of Colorado at Boulder, Boulder CO 80309 USA; Kim, Seul Cham [Department of Material Science and Engineering, Seoul National University, Seoul 151-742 South Korea; Han, Sang Sub [Department of Material Science and Engineering, Seoul National University, Seoul 151-742 South Korea; Choi, Yong Seok [Department of Material Science and Engineering, Seoul National University, Seoul 151-742 South Korea; Tian, Chixia [Energy Storage and Distributed Resources Division, Lawrence Berkeley National Laboratory, Berkeley CA 94720 USA; Nordlund, Dennis [Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park CA 94025 USA; Doeff, Marca M. [Energy Storage and Distributed Resources Division, Lawrence Berkeley National Laboratory, Berkeley CA 94720 USA; Ban, Chunmei [Center of Chemical and Materials Science, National Renewable Energy Laboratory, Golden CO 80401 USA; Cho, Sung-Jin [Joint School of Nanoscience and Nanoengineering, North Carolina A& T State University, Greensboro NC 27411 USA; Oh, Kyu Hwan [Department of Material Science and Engineering, Seoul National University, Seoul 151-742 South Korea; Lee, Se-Hee [Department of Mechanical Engineering, University of Colorado at Boulder, Boulder CO 80309 USA

    2017-01-05

    The first-ever demonstration of stabilized Si/lithium-manganese-rich full cells, capable of retaining >90% energy over early cycling and >90% capacity over more than 750 cycles at the 1C rate (100% depth-of-discharge), is made through the utilization of a modified ionic liquid electrolyte capable of forming a favorable cathode-electrolyte interface.

  4. Lithium-sulphur battery with activated carbon cloth-sulphur cathode and ionic liquid as electrolyte

    Science.gov (United States)

    Swiderska-Mocek, Agnieszka; Rudnicka, Ewelina

    2015-01-01

    In this study a binder-free activated carbon cloth-sulphur (ACC-S) composite cathode is presented. Such a cathode was obtained using the impregnating technique of microporous activated carbon cloth with elemental melted sulphur. The surface morphology of an activated carbon cloth-sulphur electrode was studied using a scanning electron microscope (SEM), which was equipped with an EDX spectroscopy attachment. Electrochemical properties of the ACC-S composite cathode was tested in an ionic liquid electrolyte consisting of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulphonyl)imide (EtMeImNTf2) and bis(trifluoromethanesulphonyl)imide (LiNTf2). The ACC-sulphur cathode working together with lithium anode was tested with the use of cyclic voltammetry (CV), galvanostatic charge/discharge cycles and electrochemical impedance spectroscopy (EIS). The capacity and cyclic stability of the ACC-S composite cathode were much better than those for the sulphur cathode (a mixture of sulphur from graphene nanoplatelets and carbon black) tested in the same ionic liquid electrolyte. The ACC-sulphur cathode showed good cyclability and coulombic efficiency (99%) with the ionic liquid electrolyte. The reversible capacity of the ACC-S|electrolyte|Li cell was ca. 830 mAh g-1 after 50 cycles.

  5. The evidence of cathodic micro-discharges during plasma electrolytic oxidation process

    Energy Technology Data Exchange (ETDEWEB)

    Nominé, A., E-mail: alexandre.nomine@univ-lorraine.fr [Institut Jean Lamour, UMR 7198 CNRS, Université de Lorraine, Parc de Saurupt, 54011 Nancy (France); National Institute of Science and Technology “MISiS,” 4, Leninskij Prospekt, Moscow 119049 (Russian Federation); Martin, J.; Noël, C.; Henrion, G.; Belmonte, T. [Institut Jean Lamour, UMR 7198 CNRS, Université de Lorraine, Parc de Saurupt, 54011 Nancy (France); Bardin, I. V.; Kovalev, V. L.; Rakoch, A. G. [National Institute of Science and Technology “MISiS,” 4, Leninskij Prospekt, Moscow 119049 (Russian Federation)

    2014-02-24

    Plasma electrolytic oxidation (PEO) processing of EV31 magnesium alloy has been carried out in fluoride containing electrolyte under bipolar pulse current regime. Unusual PEO cathodic micro-discharges have been observed and investigated. It is shown that the cathodic micro-discharges exhibit a collective intermittent behavior, which is discussed in terms of charge accumulations at the layer/electrolyte and layer/metal interfaces. Optical emission spectroscopy is used to determine the electron density (typ. 10{sup 15} cm{sup −3}) and the electron temperature (typ. 7500 K) while the role of F{sup −} anions on the appearance of cathodic micro-discharges is pointed out.

  6. On the suppression of cathodic hypochlorite reduction by electrolyte additions of molybdate and chromate ions

    Directory of Open Access Journals (Sweden)

    JOHN GUSTAVSSON

    2012-11-01

    Full Text Available The goal of this study was to gain a better understanding of the feasibility of replacing Cr(VI in the chlorate process by Mo(VI, focusing on the cathode reaction selectivity for hydrogen evolution on steel and titanium in a hypochlorite containing electrolyte. To evaluate the ability of Cr(VI and Mo(VI additions to hinder hypochlorite reduction, potential sweep experiments on rotating disc electrodes and cathodic current efficiency (CE measurements on stationary electrodes were performed. Formed electrode films were investigated with scanning electron microscopy and energy-dispersive X-ray spectroscopy. Cathodic hypochlorite reduction is hindered by the Mo-containing films formed on the cathode surface after Mo(VI addition to the electrolyte, but much less efficient compared to Cr(VI addition. Very low levels of Cr(VI, in the mM range, can efficiently suppress hypochlorite reduction on polished titanium and steel. Phosphate does not negatively influence the CE in the presence of Cr(VI or Mo(VI but the Mo-containing cathode films become thinner if the electrolyte during the film build-up also contains phosphate. For a RuO2-TiO2 anode polarized in electrolyte with 40 mM Mo(VI, the anode potential increased and increased molybdenum levels were detected on the electrode surface

  7. Cathodes for lithium-air battery cells with acid electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Xing, Yangchuan; Huang, Kan; Li, Yunfeng

    2016-07-19

    In various embodiments, the present disclosure provides a layered metal-air cathode for a metal-air battery. Generally, the layered metal-air cathode comprises an active catalyst layer, a transition layer bonded to the active catalyst layer, and a backing layer bonded to the transition layer such that the transition layer is disposed between the active catalyst layer and the backing layer.

  8. Phenomenological Treatment of the Inductive Hysteresis in the Cathode Reaction on YSZ Electrolytes

    DEFF Research Database (Denmark)

    Bay, Lasse; Zachau-Christiansen, Birgit; Jacobsen, Torben

    1999-01-01

    The cathode reaction on YSZ electrolytes shows inductive hysteresis behavior with an activation/deactivation process of the cell. This is described by a phenomenological model, where the rate of activation is proportional to the current density and the rate of deactivation is proportional...

  9. Electrochemical behavior of PEDOT/Lignin in Ionic Liquid Electrolytes: Suitable Cathode/Electrolyte System for Sodium Batteries.

    Science.gov (United States)

    Casado, Nerea; Hilder, Matthias; Pozo-Gonzalo, Cristina; Forsyth, Maria; Mecerreyes, David

    2017-02-15

    Biomass derived polymers, such as lignin, contain redox quinone/hydroquinone redox moieties that can be used to store charge. Composites based on the biopolymer lignin and several conjugated polymers have shown good charge storage properties. However, their performance has been just studied in acidic aqueous media limiting the applications mainly to supercapacitors. Here we show that PEDOT/Lignin biopolymers are electroactive in aprotic ionic liquids and we move a step further by assembling sodium full cell batteries using PEDOT/Lignin as electrode material and ionic liquid electrolytes. Thus, the electrochemical activity and cycling of PEDOT/Lignin electrodes is investigated in 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (BMPyrTFSI), 1-butyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide (BMPyrFSI), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMImTFSI) and 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMImFSI) ionic liquid electrolytes. The effects of water and sodium salt addition to the ionic liquids are investigated in order to obtain optimum electrolyte systems for sodium batteries. Finally, sodium batteries based on PEDOT/Lignin cathode with imidazolium based ionic liquid electrolyte showed higher capacity values than pyrrolidinium ones, reaching 70 mAhg-1. Our results demonstrate that PEDOT/Lignin composites can serve as low cost and sustainable cathode materials for sodium batteries.

  10. Electrolytic preparation of Al-Ca master alloy on liquid Al cathode

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    As a newly developing superplastic aluminum alloy, Al-Ca alloy has been widely used in industry, however thetechnology for preparing Al-Ca master alloy and its influencing factors need to be further studied. Therefore the Al-Camaster alloy was prepared by using liquid aluminum cathode and a mixture of 80%CaC12-18% KC1-2%CaF2 as the moltensalt electrolysis in a laboratory electrolyte cell; the effects of electrolysis temperature, cathodic current density and electrolytic duration on current efficiency and Ca content of Al-Ca alloy as well were studied. Through laboratory experiments, the parameters for smooth electrolytic reaction were proposed. The proper electrolysis technology is as follows:with the 80%CaCl2-18%KCl-2%CaF2 electrolyte, the electrolytic temperature is 973 K and the cathodic current densityis 0.8 A/cm2, the electrolysis can go on smoothly and a calcium content of 17.5%(mass fraction) can be obtained. Withthe increase of electrolysis duration, the calcium content in the alloy increasas whereas the current efficiency decreases

  11. Iron-based cathode catalyst with enhanced power density in polymer electrolyte membrane fuel cells.

    Science.gov (United States)

    Proietti, Eric; Jaouen, Frédéric; Lefèvre, Michel; Larouche, Nicholas; Tian, Juan; Herranz, Juan; Dodelet, Jean-Pol

    2011-08-02

    H(2)-air polymer-electrolyte-membrane fuel cells are electrochemical power generators with potential vehicle propulsion applications. To help reduce their cost and encourage widespread use, research has focused on replacing the expensive Pt-based electrocatalysts in polymer-electrolyte-membrane fuel cells with a lower-cost alternative. Fe-based cathode catalysts are promising contenders, but their power density has been low compared with Pt-based cathodes, largely due to poor mass-transport properties. Here we report an iron-acetate/phenanthroline/zeolitic-imidazolate-framework-derived electrocatalyst with increased volumetric activity and enhanced mass-transport properties. The zeolitic-imidazolate-framework serves as a microporous host for phenanthroline and ferrous acetate to form a catalyst precursor that is subsequently heat treated. A cathode made with the best electrocatalyst from this work, tested in H(2)-O(2,) has a power density of 0.75 W cm(-2) at 0.6 V, a meaningful voltage for polymer-electrolyte-membrane fuel cells operation, comparable with that of a commercial Pt-based cathode tested under identical conditions.

  12. Cathode-Electrolyte Interfaces with CGO Barrier Layers in SOFC

    DEFF Research Database (Denmark)

    Knibbe, Ruth; Hjelm, Johan; Menon, Mohan

    2010-01-01

    Electron microscopy characterization across the cathode–electrolyte interface of two different types of intermediate temperature solid oxide fuel cells (IT-SOFC) is performed to understand the origin of the cell performance disparity. One IT-SOFC cell had a sprayed-cosintered Ce0.90Gd0.01O1.95 (CGO......10) barrier layer, the other had a barrier layer deposited by pulsed laser deposition (PLD) CGO10. Scanning electron microscopy, transmission electron microscopy (TEM), and electron backscattered diffraction (EBSD) investigations conclude that the major source of the cell performance difference...... is attributed to CGO–YSZ interdiffusion in the sprayed-cosintered barrier layer. From TEM and EBSD work, a dense CGO10 PLD layer is found to be deposited epitaxially on the 8YSZ electrolyte substrate—permitting a small amount of SrZrO3 formation and minimizing CGO–YSZ interdiffusion....

  13. Structure and compatibility of a magnesium electrolyte with a sulphur cathode.

    Science.gov (United States)

    Kim, Hee Soo; Arthur, Timothy S; Allred, Gary D; Zajicek, Jaroslav; Newman, John G; Rodnyansky, Alexander E; Oliver, Allen G; Boggess, William C; Muldoon, John

    2011-08-09

    Magnesium metal is an ideal rechargeable battery anode material because of its high volumetric energy density, high negative reduction potential and natural abundance. Coupling Mg with high capacity, low-cost cathode materials such as electrophilic sulphur is only possible with a non-nucleophilic electrolyte. Here we show how the crystallization of the electrochemically active species formed from the reaction between hexamethyldisilazide magnesium chloride and aluminum trichloride enables the synthesis of a non-nucleophilic electrolyte. Furthermore, crystallization was essential in the identification of the electroactive species, [Mg(2)(μ-Cl)(3)·6THF](+), and vital to improvements in the voltage stability and coulombic efficiency of the electrolyte. X-ray photoelectron spectroscopy analysis of the sulphur electrode confirmed that the electrochemical conversion between sulphur and magnesium sulfide can be successfully performed using this electrolyte.

  14. High Performance Infiltrated Backbones for Cathode-Supported SOFC's

    DEFF Research Database (Denmark)

    Gil, Vanesa; Kammer Hansen, Kent

    2014-01-01

    The concept of using highly ionic conducting backbones with subsequent infiltration of electronically conducting particles has widely been used to develop alternative anode-supported SOFC's. In this work, the idea was to develop infiltrated backbones as an alternative design based on cathode......-supported SOFC. The cathodes are obtained by infiltrating LSM into a sintered either thick (300 μm) yttria stabilized zirconia (YSZ) backbone or a thin YSZ backbone (10-15 μm) integrated onto a thick (300 μm) porous strontium substituted lanthanum manganite (LSM) and YSZ composite. Fabrication challenges...... printed symmetrical cells. Samples with LSM/YSZ composite and YSZ backbones made with graphite+PMMA as pore formers exhibited comparable Rp values to the screen printed LSM/YSZ cathode. This route was chosen as the best to fabricate the cathode supported cells. SEM micrograph of a cathode supported cell...

  15. Performance of a novel type of electrolyte-supported solid oxide fuel cell with honeycomb structure

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz-Morales, Juan Carlos; Savvin, Stanislav N.; Nunez, Pedro [Departmento de Quimica Inorganica, Universidad de La Laguna, 38200 Tenerife (Spain); Marrero-Lopez, David [Departamento de Fisica Aplicada I, Universidad de Malaga, 29071 Malaga (Spain); Pena-Martinez, Juan; Canales-Vazquez, Jesus [Instituto de Energias Renovables-Universidad de Castilla la Mancha, 02006 Albacete (Spain); Roa, Joan Josep; Segarra, Merce [DIOPMA, Departamento de Ciencia de los Materiales e Ing. Metalurgica, 08028 Barcelona (Spain)

    2010-01-15

    A novel design, alternative to the conventional electrolyte-supported solid oxide fuel cell (SOFC) is presented. In this new design, a honeycomb-electrolyte is fabricated from hexagonal cells, providing high mechanical strength to the whole structure and supporting the thin layer used as electrolyte of a SOFC. This new design allows a reduction of {proportional_to}70% of the electrolyte material and it renders modest performances over 320 mW cm{sup -2} but high volumetric power densities, i.e. 1.22 W cm{sup -3} under pure CH{sub 4} at 900 C, with a high OCV of 1.13 V, using the standard Ni-YSZ cermet as anode, Pt as cathode material and air as the oxidant gas. (author)

  16. Nanocomposite Materials for Cathodes and Electrolytes in Lithium Batteries

    Institute of Scientific and Technical Information of China (English)

    F. Croce; C.R. Martin; B. Scrosati; L. Settimi; C. Sides

    2005-01-01

    @@ 1Introduction Lithium-ion batteries are today the power sources of choice far portable electronics, a multi-billion dollar market[1]. This outstanding success has spawned great international interest in applying this technology to more demanding systems, such as electric of hybrid vehicles[2]. However, to achieve full success in this area,new electrode materials, less expensive, more energetic and more compatible with the environment than the present ones, have to be identified. Accordingly, intense R&D are in progress to reach this goal and few variable alternatives to the original lithium-ion battery design, have been proposed. Particularly interesting is the olivine-structured LiFePO4 cathode developed by Goodenough and co-workers[3], which offers several appealing features, such as high, flat voltage profile and relatively high specific capacity, combined with low cost and low toxicity. However, LiFePO4 has one crucial disadvantage, i.e. its inherently low electric conductivity which reflects in the inability to deliver high capacity at high discharge rates. Such as poor rate capability has been the object of investigation by various groups who have proposed different approaches to overcome it, including carbon coating[4], nano-fibril textures[5], optimized synthesis procedures[6] and foreign metal doping[7].

  17. Advanced cathode materials for polymer electrolyte fuel cells based on pt/ metal oxides: from model electrodes to catalyst systems.

    Science.gov (United States)

    Fabbri, Emiliana; Pătru, Alexandra; Rabis, Annett; Kötz, Rüdiger; Schmidt, Thomas J

    2014-01-01

    The development of stable catalyst systems for application at the cathode side of polymer electrolyte fuel cells (PEFCs) requires the substitution of the state-of-the-art carbon supports with materials showing high corrosion resistance in a strongly oxidizing environment. Metal oxides in their highest oxidation state can represent viable support materials for the next generation PEFC cathodes. In the present work a multilevel approach has been adopted to investigate the kinetics and the activity of Pt nanoparticles supported on SnO2-based metal oxides. Particularly, model electrodes made of SnO2 thin films supporting Pt nanoparticles, and porous catalyst systems made of Pt nanoparticles supported on Sb-doped SnO2 high surface area powders have been investigated. The present results indicate that SnO2-based supports do not modify the oxygen reduction reaction mechanism on the Pt nanoparticle surface, but rather lead to catalysts with enhanced specific activity compared to Pt/carbon systems. Different reasons for the enhancement in the specific activity are considered and discussed.

  18. Performance of Electrolyte Supported Solid Oxide Fuel Cells with STN Anodes

    DEFF Research Database (Denmark)

    Veltzé, Sune; Reddy Sudireddy, Bhaskar; Jørgensen, Peter Stanley

    2013-01-01

    In order to replace the state of the art Ni-cermet as SOFC anode, electrolyte supported cells comprising CGO/Ni infiltrated Nbdoped SrTiO3 anodes, and LSM/YSZ cathodes have been developed and tested as single 5 x 5 cm2 cells. The initial performance reached 0.4 W/cm2 at 850 C. Further tests under...

  19. All-solid-state lithium organic battery with composite polymer electrolyte and pillar[5]quinone cathode.

    Science.gov (United States)

    Zhu, Zhiqiang; Hong, Meiling; Guo, Dongsheng; Shi, Jifu; Tao, Zhanliang; Chen, Jun

    2014-11-26

    The cathode capacity of common lithium ion batteries (LIBs) using inorganic electrodes and liquid electrolytes must be further improved. Alternatively, all-solid-state lithium batteries comprising the electrode of organic compounds can offer much higher capacity. Herein, we successfully fabricated an all-solid-state lithium battery based on organic pillar[5]quinone (C35H20O10) cathode and composite polymer electrolyte (CPE). The poly(methacrylate) (PMA)/poly(ethylene glycol) (PEG)-LiClO4-3 wt % SiO2 CPE has an optimum ionic conductivity of 0.26 mS cm(-1) at room temperature. Furthermore, pillar[5]quinine cathode in all-solid-state battery rendered an average operation voltage of ∼2.6 V and a high initial capacity of 418 mAh g(-1) with a stable cyclability (94.7% capacity retention after 50 cycles at 0.2C rate) through the reversible redox reactions of enolate/quinonid carbonyl groups, showing favorable prospect for the device application with high capacity.

  20. Fervent Hype behind Magnesium Batteries: An Open Call to Synthetic Chemists - Electrolytes and Cathodes Needed.

    Science.gov (United States)

    Muldoon, John; Bucur, Claudiu B; Gregory, Thomas

    2017-03-10

    Magnesium metal is an ideal anode which has double the volumetric capacity of lithium metal and has a negative reduction potential of -2.37V vs. the standard hydrogen electrode. The major advantage of magnesium is the apparent lack of dendritic formation during charging which is one of the major concerns of using a lithium metal anode. In this review, we highlight the major research in the development of electrolytes and cathodes and discuss some of the major challenges which must be overcome in realizing a practical magnesium battery.

  1. Performances of Anode-Supported BZCY Electrolyte and GBFN Cathode Membranes in Ammonia Synthesis at Atmospheric Pressure%阳极支撑BZCY电解质及GBFN阴极膜在常压合成氨中的性能研究

    Institute of Scientific and Technical Information of China (English)

    朱剑莉; 马桂林; 占忠亮

    2012-01-01

    BaZr0.1Ce0.7 Y0.2O3-α( BZCY) proton-conducting electrolyte and GdBaFeNiO5+δ(GBFN) cathode materials were prepared by the citric-nitrate process. A membrane reactor for ammonia synthesis was successfully fabricated through the following process; an anode-supported dense BZCY electrolyte membrane was first fabricated, and then on the membrane porous GBFN cathode membrane was fabricated by a simple spin coating process combined with heat treatment. The ammonia synthesis test was conducted by an electrolytic method using H2 and N2 as reactant gases. The results indicated that BZCY and GBFN were perovskite and double perovskite structures, respectively. The anode substrate showed good chemical compatibility between NiO and BZCY, and the maximum ammonia formation rate reached 1. 63 x 10-8 mol os~1ocm~2, which was higher than the reported values by similar methods to date. The high maximum ammonia formation rate mould be closely relevant to excellent electrical conduction performance for BZCY and excellent polarization performance for GBFN. The modification of Ag on the GBFN cathode was also beneficial for enhancing the ammonia formation rate.%采用硝酸盐-柠檬酸法制备了 BaZr0.1 Ce0.7 Y0.2 O3-α(BZCY)质子电解质及GdBaFeNiO5+δ(GBFN)阴极材料,用浆料旋涂法结合后续的热处理在NiO-BZCY阳极支撑体上制备致密的BZCY电解质薄膜,在电解质薄膜上制备多孔性GBFN阴极膜,成功地组装成合成氨膜反应器.以氢、氮气为反应气体,通过电解方法进行了常压合成氨试验.结果显示,BZCY及GBFN分别具有钙钛矿型及双钙钛矿型结构,NiO与BZ-CY具有良好的化学兼容性,合成氨产率高达1.63 ×10-8 mol·s-1·cm-2,高于迄今所报道的类似方法的合成氨产率.这与BZCY电解质膜优良的导电性能、GBFN膜优良的极化性能密切相关.Ag对GBFN的修饰也有利于氨产率的提高.

  2. Optimization of the Interconnect Ribs for a Cathode-Supported Solid Oxide Fuel Cell

    Directory of Open Access Journals (Sweden)

    Wei Kong

    2014-01-01

    Full Text Available A comprehensive mathematical model of the performance of the cathode-supported solid oxide fuel cell (SOFC with syngas fuel is presented. The model couples the intricate interdependency between the ionic conduction, electronic conduction, gas transport, the electrochemical reaction processes in the functional layers and on the electrode/electrolyte interfaces, methane steam reforming (MSR and the water gas shift reaction (WGSR. The validity of the mathematical model is demonstrated by the excellent agreement between the numerical and experimental I-V curves. The effect of anode rib width and cathode rib width on gas diffusion and cell performance is examined. The results show conclusively that the cell performance is strongly influenced by the rib width. Furthermore, the anode optimal rib width is smaller than that for cathode, which is contrary to anode-supported SOFC. Finally, the formulae for the anode and cathode optimal rib width are given, which provide an easy to use guidance for the broad SOFC engineering community.

  3. Ferrite-based perovskites as cathode materials for anode-supported solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Mai, Andreas; Haanappel, Vincent A.C.; Uhlenbruck, Sven; Tietz, Frank; Stoever, Detlev [Institute for Materials and Processes in Energy Systems, Forschungszentrum Juelich, IWV-1, D-52425 Juelich (Germany)

    2005-05-12

    The properties and the applicability of iron- and cobalt-containing perovskites were evaluated as cathodes for solid oxide fuel cells (SOFCs) in comparison to state-of-the-art manganite-based perovskites. The materials examined were La{sub 1-x-y}Sr{sub x}Co{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}} (x=0.2 and 0.4; y=0-0.05), La{sub 0.8}Sr{sub 0.2}FeO{sub 3-{delta}}, La{sub 0.7}Ba{sub 0.3}Co{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}} and Ce{sub 0.05}Sr{sub 0.95}Co{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}}. The main emphasis was placed on the electrochemical properties of the materials, which were investigated on planar anode-supported SOFCs with 8 mol% yttria-stabilised zirconia (8YSZ) electrolytes. An interlayer of the composition Ce{sub 0.8}Gd{sub 0.2}O{sub 2-{delta}} was placed between the electrolyte and the cathode to prevent undesired chemical reactions between the materials. The sintering temperatures of the cathodes were adapted for each of the materials to obtain similar microstructures. In comparison to the SOFCs with state-of-the-art manganite-based cathodes, SOFCs with La{sub 1-x-y}Sr{sub x}Co{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}} cathodes achieved much higher current densities. Small A-site deficiency and high strontium content had a particularly positive effect on cell performance. The measured current densities of cells with these cathodes were as high as 1.76 A/cm{sup 2} at 800 {sup o}C and 0.7 V, which is about twice the current density of cells with LSM/YSZ cathodes. SOFCs with La{sub 0.58}Sr{sub 0.4}Co{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}} cathodes have been operated for more than 5000 h in endurance tests with a degradation of 1.0-1.5% per 1000 h.

  4. PRELIMINARY IN-SITU X-RAY ABSORPTION FINE STRUCTURE EXAMINATION OF PT/C AND PTCO/C CATHODE CATALYSTS IN AN OPERATIONAL POLYMER ELECTROLYTE FUEL CELL

    Energy Technology Data Exchange (ETDEWEB)

    Phelan, B.T.; Myers, D.J.; Smith, M.C.

    2009-01-01

    State-of-the-art polymer electrolyte fuel cells require a conditioning period to reach optimized cell performance. There is insuffi cient understanding about the behavior of catalysts during this period, especially with regard to the changing environment of the cathode electrocatalyst, which is typically Pt nanoparticles supported on high surface area Vulcan XC-72 carbon (Pt/C). The purpose of this research was to record preliminary observations of the changing environment during the conditioning phase using X-Ray Absorption Fine Structure (XAFS) spectroscopy. XAFS was recorded for a Pt/C cathode at the Pt L3-edge and a PtCo/C cathode at both the Pt L3-edge and Co K-edge. Using precision machined graphite cell-blocks, both transmission and fl uorescence data were recorded at Sector 12-BM-B of Argonne National Laboratory’s Advanced Photon Source. The fl uorescence and transmission edge steps allow for a working description of the changing electrocatalyst environment, especially water concentration, at the anode and cathode as functions of operating parameters. These features are discussed in the context of how future analysis may correlate with potential, current and changing apparent thickness of the membrane electrode assembly through loss of catalyst materials (anode, cathode, carbon support). Such direct knowledge of the effect of the conditioning protocol on the electrocatalyst may lead to better catalyst design. In turn, this may lead to minimizing, or even eliminating, the conditioning period.

  5. Solid polymer electrolyte composite membrane comprising laser micromachined porous support

    Science.gov (United States)

    Liu, Han; LaConti, Anthony B.; Mittelsteadt, Cortney K.; McCallum, Thomas J.

    2011-01-11

    A solid polymer electrolyte composite membrane and method of manufacturing the same. According to one embodiment, the composite membrane comprises a rigid, non-electrically-conducting support, the support preferably being a sheet of polyimide having a thickness of about 7.5 to 15 microns. The support has a plurality of cylindrical pores extending perpendicularly between opposing top and bottom surfaces of the support. The pores, which preferably have a diameter of about 5 microns, are made by laser micromachining and preferably are arranged in a defined pattern, for example, with fewer pores located in areas of high membrane stress and more pores located in areas of low membrane stress. The pores are filled with a first solid polymer electrolyte, such as a perfluorosulfonic acid (PFSA) polymer. A second solid polymer electrolyte, which may be the same as or different than the first solid polymer electrolyte, may be deposited over the top and/or bottom of the first solid polymer electrolyte.

  6. Nickel foam-supported polyaniline cathode prepared with electrophoresis for improvement of rechargeable Zn battery performance

    Science.gov (United States)

    Xia, Yang; Zhu, Derong; Si, Shihui; Li, Degeng; Wu, Sen

    2015-06-01

    Porous nickel foam is used as a substrate for the development of rechargeable zinc//polyaniline battery, and the cathode electrophoresis of PANI microparticles in non-aqueous solution is applied to the fabrication of Ni foam supported PANI electrode, in which the corrosion of the nickel foam substrate is prohibited. The Ni foam supported PANI cathode with high loading is prepared by PANI electrophoretic deposition, and followed by PANI slurry casting under vacuum filtration. The electrochemical charge storage performance for PANI material is significantly improved by using nickel foam substrate via the electrophoretic interlayer. The specific capacity of the nickel foam-PANI electrode with the electrophoretic layer is higher than the composite electrode without the electrophoretic layer, and the specific capacity of PANI supported by Ni foam reaches up to 183.28 mAh g-1 at the working current of 2.5 mA cm-2. The present electrophoresis deposition method plays the facile procedure for the immobilization of PANI microparticles onto the surface of non-platinum metals, and it becomes feasible to the use of the Ni foam supported PANI composite cathode for the Zn/PANI battery in weak acidic electrolyte.

  7. Methods for using novel cathode and electrolyte materials for solid oxide fuel cells and ion transport membranes

    Energy Technology Data Exchange (ETDEWEB)

    Jacobson, Allan J.; Wang, Shuangyan; Kim, Gun Tae

    2016-01-12

    Methods using novel cathode, electrolyte and oxygen separation materials operating at intermediate temperatures for use in solid oxide fuel cells and ion transport membranes include oxides with perovskite related structures and an ordered arrangement of A site cations. The materials have significantly faster oxygen kinetics than in corresponding disordered perovskites.

  8. Maintaining structural integrity of 4.5 V lithium cobalt oxide cathode with fumaronitrile as a novel electrolyte additive

    Science.gov (United States)

    Wang, Xianshu; Zheng, Xiongwen; Liao, Youhao; Huang, Qiming; Xing, Lidan; Xu, Mengqing; Li, Weishan

    2017-01-01

    The specific capacity of lithium-ion battery with lithium cobalt oxide as cathode depends on the upper limitation voltage for charge/discharge cycling, but this oxide tends to be destructed structurally when it is cycled in carbonate-based electrolyte under high voltage. We report a novel electrolyte additive, fumaronitrile (FN, CNsbnd CHdbnd CHsbnd CN), which can maintain the structural integrity of lithium cobalt oxide. Electrochemical measurements indicate that lithium cobalt oxide exhibits poor cyclic stability when it is cycled under 4.5 V (vs. Li/Li+) and the charged cathode suffers serious self-discharge in a base electrolyte, 1.0 mol L-1 LiPF6 in EC/EMC/DEC (3:5:2, by weight). These issues can be overcome effectively by adding 0.5% FN into the base electrolyte. Physical and chemical characterizations demonstrate that the poor cyclic stability and self-discharge of lithium cobalt oxide result from its structural destruction caused by HF formed from electrolyte decomposition, and FN yields a protective cathode interphase film which maintains the structural integrity of lithium cobalt oxide.

  9. Highly durable anode supported solid oxide fuel cell with an infiltrated cathode

    Science.gov (United States)

    Samson, Alfred Junio; Hjalmarsson, Per; Søgaard, Martin; Hjelm, Johan; Bonanos, Nikolaos

    2012-10-01

    An anode supported solid oxide fuel cell with an La0.6Sr0.4Co1.05O3-δ (LSC) infiltrated-Ce0.9Gd0.1O1.95 (CGO) cathode that shows a stable performance has been developed. The cathode was prepared by screen printing a porous CGO backbone on top of a laminated and co-fired anode supported half cell, consisting of a Ni-yttria stabilized zirconia (YSZ) anode support, a Ni-scandia-doped yttria-stabilized zirconia (ScYSZ) anode, a ScYSZ electrolyte, and a CGO barrier layer. LSC was introduced into the CGO backbone by multiple infiltrations of an aqueous nitrate solution followed by firing. The cell was tested at 700 °C under a current density of 0.5 A cm-2 for 1500 h using air as oxidant and humidified hydrogen as fuel. The electrochemical performance of the cell was analyzed by impedance spectroscopy and current-voltage relationships. No measurable degradation in the cell voltage or increase in the resistance from the recorded impedance was observed during long term testing. The power density reached 0.79 W cm-2 at a cell voltage of 0.6 V at 750 °C. Post test analysis of the LSC infiltrated-CGO cathode by scanning electron microscopy revealed no significant micro-structural difference to that of a nominally identical untested counterpart.

  10. Advances in lithium-sulfur batteries based on multifunctional cathodes and electrolytes

    Science.gov (United States)

    Pang, Quan; Liang, Xiao; Kwok, Chun Yuen; Nazar, Linda F.

    2016-09-01

    Amid burgeoning environmental concerns, electrochemical energy storage has rapidly gained momentum. Among the contenders in the ‘beyond lithium’ energy storage arena, the lithium-sulfur (Li-S) battery has emerged as particularly promising, owing to its potential to reversibly store considerable electrical energy at low cost. Whether or not Li-S energy storage will be able to fulfil this potential depends on simultaneously solving many aspects of its underlying conversion chemistry. Here, we review recent developments in tackling the dissolution of polysulfides — a fundamental problem in Li-S batteries — focusing on both experimental and computational approaches to tailor the chemical interactions between the sulfur host materials and polysulfides. We also discuss smart cathode architectures enabled by recent materials engineering, especially for high areal sulfur loading, as well as innovative electrolyte design to control the solubility of polysulfides. Key factors that allow long-life and high-loading Li-S batteries are summarized.

  11. Assessment of the cathode contribution to the degradation of anode-supported solid oxide fuel cells

    DEFF Research Database (Denmark)

    Hagen, Anke; Liu, Yi-Lin; Barfod, Rasmus

    2008-01-01

    of these craters observed after testing correlated with the cell voltage degradation rates. The results can be interpreted in terms of element redistribution at the cathode/electrolyte interface and formation of foreign phases giving rise to a weakening of local contact points of the LSM cathode and yttria...

  12. Investigation of a chemically regenerative redox cathode polymer electrolyte fuel cell using a phosphomolybdovanadate polyoxoanion catholyte

    Science.gov (United States)

    Gunn, Natasha L. O.; Ward, David B.; Menelaou, Constantinos; Herbert, Matthew A.; Davies, Trevor J.

    2017-04-01

    Chemically regenerative redox cathode (CRRC) polymer electrolyte fuel cells (PEFCs), where the direct reduction of oxygen is replaced by an in-direct mechanism occurring outside of the cell, are attractive to study as they offer a solution to the cost and durability problems faced by conventional PEFCs. This study reports the first detailed characterization of a high performance complete CRRC PEFC system, where catholyte is circulated between the cathode side of the cell and an air-liquid oxidation reactor called the ;regenerator;. The catholyte is an aqueous solution of phosphomolybdovanadate polyoxoanion and is assessed in terms of its performance within both a small single cell and corresponding regenerator over a range of redox states. Two methods for determining regeneration rate are proposed and explored. Expressing the regeneration rate as a ;chemical; current is suggested as a useful means of measuring re-oxidation rate with respect to the cell. The analysis highlights the present limitations to the technology and provides an indication of the maximum power density achievable, which is highly competitive with conventional PEFC systems.

  13. Real-time imaging, spectroscopy, and structural investigation of cathodic plasma electrolytic oxidation of molybdenum

    Energy Technology Data Exchange (ETDEWEB)

    Stojadinović, Stevan, E-mail: sstevan@ff.bg.ac.rs; Tadić, Nenad; Šišović, Nikola M.; Vasilić, Rastko [Faculty of Physics, University of Belgrade, Studentski trg 12-16, 11000 Belgrade (Serbia)

    2015-06-21

    In this paper, the results of the investigation of cathodic plasma electrolytic oxidation (CPEO) of molybdenum at 160 V in a mixed solution of borax, water, and ethylene glycol are presented. Real-time imaging and optical emission spectroscopy were used for the characterization of the CPEO. During the process, vapor envelope is formed around the cathode and strong electric field within the envelope caused the generation of plasma discharges. The spectral line shape analysis of hydrogen Balmer line H{sub β} (486.13 nm) shows that plasma discharges are characterized by the electron number density of about 1.4 × 10{sup 21 }m{sup −3}. The electron temperature of 15 000 K was estimated by measuring molybdenum atomic lines intensity. Surface morphology, chemical, and phase composition of coatings formed by CPEO were characterized by scanning electron microscopy with energy dispersive x-ray spectroscopy and x-ray diffraction. The elemental components of CPEO coatings are Mo and O and the predominant crystalline form is MoO{sub 3}.

  14. Solvents and supporting electrolytes for vanadium acetylacetonate flow batteries

    Science.gov (United States)

    Shinkle, Aaron A.; Pomaville, Timothy J.; Sleightholme, Alice E. S.; Thompson, Levi T.; Monroe, Charles W.

    2014-02-01

    Properties of supporting electrolytes and solvents were examined for use with vanadium acetylacetonate - a member of the class of metal(β-diketonate) active species - in non-aqueous redox flow batteries. Twenty supporting-electrolyte/solvent combinations were screened for ionic conductivity and supporting-electrolyte solubility. Hexane, tetrahydrofuran, and dimethylcarbonate solvents did not meet minimal conductivity and solubility criteria for any of the electrolytes used, which included tetraethylammonium tetrafluoroborate, tetrabutylammonium tetrafluoroborate, tetrabutylammonium hexafluorophosphate, and (1-butyl, 3-methyl)imidazolium bis(trifluoromethanesulfonyl)imide. Ionic conductivities and solubilities for solutions of these electrolytes passed screening criteria in acetonitrile and dimethylformamide solvents, in which maximum supporting-electrolyte and active-species solubilities were determined. Active-species electrochemistry was found to be reversible in several solvent/support systems; for some systems the voltammetric signatures of unwanted side reactions were suppressed. Correlations between supporting-solution properties and performance metrics suggest that an optimal solvent for a vanadium acetylacetonate RFB should have a low solvent molar volume for active-species solubility, and a high Hansen polarity for conductivity.

  15. Hierarchically oriented macroporous anode-supported solid oxide fuel cell with thin ceria electrolyte film.

    Science.gov (United States)

    Chen, Yu; Zhang, Yanxiang; Baker, Jeffrey; Majumdar, Prasun; Yang, Zhibin; Han, Minfang; Chen, Fanglin

    2014-04-09

    Application of anode-supported solid oxide fuel cell (SOFC) with ceria based electrolyte has often been limited by high cost of electrolyte film fabrication and high electrode polarization. In this study, dense Gd0.1Ce0.9O2 (GDC) thin film electrolytes have been fabricated on hierarchically oriented macroporous NiO-GDC anodes by a combination of freeze-drying tape-casting of the NiO-GDC anode, drop-coating GDC slurry on NiO-GDC anode, and co-firing the electrolyte/anode bilayers. Using 3D X-ray microscopy and subsequent analysis, it has been determined that the NiO-GDC anode substrates have a porosity of around 42% and channel size from around 10 μm at the electrolyte side to around 20 μm at the other side of the NiO-GDC (away from the electrolyte), indicating a hierarchically oriented macroporous NiO-GDC microstructure. Such NiO-GDC microstructure shows a tortuosity factor of ∼1.3 along the thickness direction, expecting to facilitate gas diffusion in the anode during fuel cell operation. SOFCs with such Ni-GDC anode, GDC film (30 μm) electrolyte, and La0.6Sr0.4Co0.2Fe0.8O3-GDC (LSCF-GDC) cathode show significantly enhanced cell power output of 1.021 W cm(-2) at 600 °C using H2 as fuel and ambient air as oxidant. Electrochemical Impedance Spectroscopy (EIS) analysis indicates a decrease in both activation and concentration polarizations. This study has demonstrated that freeze-drying tape-casting is a very promising approach to fabricate hierarchically oriented porous substrate for SOFC and other applications.

  16. Determination of optimal parameters for dual-layer cathode of polymer electrolyte fuel cell using computational intelligence-aided design.

    Science.gov (United States)

    Chen, Yi; Huang, Weina; Peng, Bei

    2014-01-01

    Because of the demands for sustainable and renewable energy, fuel cells have become increasingly popular, particularly the polymer electrolyte fuel cell (PEFC). Among the various components, the cathode plays a key role in the operation of a PEFC. In this study, a quantitative dual-layer cathode model was proposed for determining the optimal parameters that minimize the over-potential difference η and improve the efficiency using a newly developed bat swarm algorithm with a variable population embedded in the computational intelligence-aided design. The simulation results were in agreement with previously reported results, suggesting that the proposed technique has potential applications for automating and optimizing the design of PEFCs.

  17. Degradation behavior of anode-supported solid oxide fuel cell using LNF cathode as function of current load

    Energy Technology Data Exchange (ETDEWEB)

    Komatsu, Takeshi; Yoshida, Yoshiteru; Watanabe, Kimitaka; Chiba, Reiichi; Taguchi, Hiroaki; Orui, Himeko; Arai, Hajime [NTT Energy and Environment Systems Laboratories, Atsugi-shi, Kanagawa 243-0198 (Japan)

    2010-09-01

    We investigated the effect of current loading on the degradation behavior of an anode-supported solid oxide fuel cell (SOFC). The cell consisted of LaNi{sub 0.6}Fe{sub 0.4}O{sub 3} (LNF), alumina-doped scandia stabilized zirconia (SASZ), and a Ni-SASZ cermet as the cathode, electrolyte, and anode, respectively. The test was carried out at 1073 K with constant loads of 0.3, 1.0, 1.5, and 2.3 A cm{sup -2}. The degradation rate, defined by the voltage loss during a fixed period (about 1000 h), was faster at higher current densities. From an impedance analysis, the degradation depended mainly on increases in the cathodic resistance, while the anodic and ohmic resistances contributed very little. The cathode microstructures were observed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). (author)

  18. Effects of cathodic voltages on structure and wear resistance of plasma electrolytic oxidation coatings formed on aluminium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Li, Qingbiao [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); School of Science, Lanzhou University of Technology, Lanzhou 730050 (China); Liang, Jun, E-mail: jliang@licp.cas.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Liu, Baixing; Peng, Zhenjun [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Wang, Qing [School of Science, Lanzhou University of Technology, Lanzhou 730050 (China)

    2014-04-01

    Highlights: • The PEO coating growth rate increased with the cathodic voltage increasing. • Higher cathodic voltage resulted in more compact coating structure. • The compact structure led to low surface roughness and high wear resistance. - Abstract: Plasma electrolytic oxidation (PEO) coatings were prepared on aluminium alloy using pulsed bipolar power supply at constant anodic voltage and different cathodic voltages. The samples were prepared to attain the same coating thickness by adjusting the processing time. The scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD) and tribometer were employed to investigate the microstructure, element content, phase composition and wear resistance of the coatings respectively. It was found that the coating growth rate enhanced obviously and the coatings exhibited a more compact structure with thicker inner layer and lower surface roughness when the cathodic voltage increased. The coatings were mainly composed of crystalline γ-Al{sub 2}O{sub 3} and amorphous silicate oxides and their relative content changed with the cathodic voltage. The wear resistance of the coatings improved significantly with the increase of cathodic voltage.

  19. Solid polymer electrolyte composite membrane comprising plasma etched porous support

    Science.gov (United States)

    Liu, Han; LaConti, Anthony B.

    2010-10-05

    A solid polymer electrolyte composite membrane and method of manufacturing the same. According to one embodiment, the composite membrane comprises a rigid, non-electrically-conducting support, the support preferably being a sheet of polyimide having a thickness of about 7.5 to 15 microns. The support has a plurality of cylindrical pores extending perpendicularly between opposing top and bottom surfaces of the support. The pores, which preferably have a diameter of about 0.1 to 5 microns, are made by plasma etching and preferably are arranged in a defined pattern, for example, with fewer pores located in areas of high membrane stress and more pores located in areas of low membrane stress. The pores are filled with a first solid polymer electrolyte, such as a perfluorosulfonic acid (PFSA) polymer. A second solid polymer electrolyte, which may be the same as or different than the first solid polymer electrolyte, may be deposited over the top and/or bottom of the first solid polymer electrolyte.

  20. Improving cyclic stability of lithium nickel manganese oxide cathode at elevated temperature by using dimethyl phenylphosphonite as electrolyte additive

    Science.gov (United States)

    Mai, Shaowei; Xu, Mengqing; Liao, Xiaolin; Xing, Lidan; Li, Weishan

    2015-01-01

    A novel electrolyte additive, dimethyl phenylphosphonite (DMPP), is reported in this paper to be able to improve significantly the cyclic stability of LiNi0.5Mn1.5O4 cathode of high voltage lithium ion battery at elevated temperature. When experiencing charge/discharge cycling at 50 °C with 1C (1C = 146.7 mAh g-1) rate in a standard (STD) electrolyte (1.0 M LiPF6 in ethylene carbonate (EC)/dimethyl carbonate (DMC), EC/DMC = 1/2 in volume), LiNi0.5Mn1.5O4 suffers serious discharge capacity decaying, with a capacity retention of 42% after 100 cycles. With adding 0.5% DMPP into the STD electrolyte, the capacity retention is increased to 91%. This improvement can be ascribed to the preferential oxidation of DMPP to the STD electrolyte and the subsequent formation of a protective film on LiNi0.5Mn1.5O4, which suppresses the electrolyte decomposition and protects LiNi0.5Mn1.5O4 from destruction. Theoretical calculations together with voltammetric analyses demonstrate the preferential oxidation of DMPP and the consequent suppression of electrolyte decomposition, while the observations from scanning electron microscopy, X-ray photoelectronic spectroscopy and Fourier transform infrared spectroscopy confirm the protection that DMPP provides for LiNi0.5Mn1.5O4.

  1. Effects of cathode electrolyte interfacial (CEI) layer on long term cycling of all-solid-state thin-film batteries

    Science.gov (United States)

    Wang, Ziying; Lee, Jungwoo Z.; Xin, Huolin L.; Han, Lili; Grillon, Nathanael; Guy-Bouyssou, Delphine; Bouyssou, Emilien; Proust, Marina; Meng, Ying Shirley

    2016-08-01

    All-solid-state lithium-ion batteries have the potential to not only push the current limits of energy density by utilizing Li metal, but also improve safety by avoiding flammable organic electrolyte. However, understanding the role of solid electrolyte - electrode interfaces will be critical to improve performance. In this study, we conducted long term cycling on commercially available lithium cobalt oxide (LCO)/lithium phosphorus oxynitride (LiPON)/lithium (Li) cells at elevated temperature to investigate the interfacial phenomena that lead to capacity decay. STEM-EELS analysis of samples revealed a previously unreported disordered layer between the LCO cathode and LiPON electrolyte. This electrochemically inactive layer grew in thickness leading to loss of capacity and increase of interfacial resistance when cycled at 80 °C. The stabilization of this layer through interfacial engineering is crucial to improve the long term performance of thin-film batteries especially under thermal stress.

  2. Highly stable linear carbonate-containing electrolytes with fluoroethylene carbonate for high-performance cathodes in sodium-ion batteries

    Science.gov (United States)

    Lee, Yongwon; Lee, Jaegi; Kim, Hyungsub; Kang, Kisuk; Choi, Nam-Soon

    2016-07-01

    Employing linear carbonates such as dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) as electrolyte solvents provides an opportunity to design appropriate electrolyte systems for high-performance sodium-ion batteries (SIBs). However, in practice, the use of linear carbonate-containing electrolytes is quite challenging because linear carbonates readily decompose at Na metal electrodes or sodiated anodes. One of the promising approaches is using an electrolyte additive to resolve the critical problems related to linear carbonates. Our investigation reveals that remarkable enhancement in electrochemical performance of Na4Fe3(PO4)2(P2O7) cathodes with linear carbonate-containing electrolytes is achieved by using a fluoroethylene carbonate (FEC) additive. Importantly, the initial Coulombic efficiency of the Na deposition/stripping on a stainless steel (SS) electrode is drastically improved from 16% to 90% by introducing the FEC additive into ethylene carbonate (EC)/propylene carbonate (PC)/DEC (5/3/2, v/v/v)/0.5 M NaClO4. The underlying mechanism of FEC at the electrode-electrolyte interface is clearly demonstrated by 13C nuclear magnetic resonance (NMR). In addition, the Na4Fe3(PO4)2(P2O7) cathode in EC/PC/DEC (5/3/2, v/v/v)/0.5 M sodium perchlorate (NaClO4) with FEC delivers a discharge capacity of 90.5 mAh g-1 at a current rate of C/2 and exhibits excellent capacity retention of 97.5% with high Coulombic efficiency of 99.6% after 300 cycles at 30 °C.

  3. Development of electrolyte-supported intermediate-temperature single-chamber solid oxide fuel cells using Ln{sub 0.7}Sr{sub 0.3}Fe{sub 0.8}Co{sub 0.2}O{sub 3-{delta}} (Ln = Pr, La, Gd) cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz de Larramendi, I.; Ruiz de Larramendi, J.I.; Rojo, T. [Departamento de Quimica Inorganica, Universidad del Pais Vasco, Apdo.644, 48080 Bilbao (Spain); Lamas, D.G.; Cabezas, M.D.; Walsoee de Reca, N.E. [CINSO, CONICET-CITEFA, J.B. de La Salle 4397 (B1603ALO) Villa Martelli, Pcia. de Buenos Aires (Argentina)

    2009-09-05

    Iron-cobalt-based perovskite oxides with general formula Ln{sub 0.7}Sr{sub 0.3}Fe{sub 0.8}Co{sub 0.2}O{sub 3-{delta}} (where Ln = La, Pr and Gd) have been investigated for their application as intermediate-temperature cathodes in solid oxide fuel cells (SOFCs). Powdered samples of these materials were synthesized by a novel gel combustion process and then characterized by X-ray powder diffraction (XPD) and scanning electron microscopy (SEM). XPD patterns were satisfactorily indexed with an orthorhombic GdFeO{sub 3}-type structure and, for all samples, a mean particle size of less than 1 {mu}m was estimated from the SEM data. Experimental single-chamber SOFCs using with these materials as cathodes and NiO-SDC (samaria-doped ceria) and SDC as anode and electrolyte, respectively, were evaluated at 600 C in a methane/oxygen mixtures. Peak power densities of 65.4, 48.7 and 46.2 mW cm{sup -2} were obtained for Ag vertical stroke Ln{sub 0.7}Sr{sub 0.3}Fe{sub 0.8}Co{sub 0.2}O{sub 3-{delta}} vertical stroke SDC vertical stroke NiO-SDC vertical stroke Pt cells with Ln = Pr, La and Gd, respectively. The relatively high power density obtained for the Pr compound shows that it could be an interesting material for cathode of single-chamber SOFCs. (author)

  4. Membrane fuel cell cathode catalysts based on titanium oxide supported platinum nanoparticles.

    Science.gov (United States)

    Gebauer, Christian; Jusys, Zenonas; Wassner, Maximilian; Hüsing, Nicola; Behm, R Jürgen

    2014-07-21

    The potential of platinum catalysts supported on pure, nitrogen-, or carbon-doped titania for application in the oxygen reduction reaction (ORR), as a cathode catalyst in polymer electrolyte membrane fuel cells, is investigated. The oxide supports are synthesized by using a sol-gel route. Modification with nitrogen and carbon doping is achieved by thermal decomposition of urea and the structure-directing agent P123. Platinum nanoparticles are prepared by reduction of a Pt(IV) salt in ethylene glycol and subsequently immobilized on different support materials. Structural and electronic properties of the support materials and the resulting catalysts are characterized by various methods, including X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. These results and electrochemical characterization of the support materials and platinum nanoparticle catalysts indicate distinct support effects in the catalysts. The electrocatalytic performance of these catalysts in the ORR, as determined in rotating ring disc electrode measurements, is promising. Also here, distinct support effects can be identified. Correlations with the structural/electronic and the electrochemical properties are discussed, as well as the role of metal-support interactions.

  5. Transport parameters of thin, supported cathode layers in solid oxide fuel cells (SOFCs); Transportparameter duenner, getraegerter Kathodenschichten der oxidkeramischen Brennstoffzelle

    Energy Technology Data Exchange (ETDEWEB)

    Wedershoven, Christian

    2010-12-22

    The aim of this work was to determine the transport properties of thin cathode layers, which are part of the composite layer of a fabricated anode-supported solid oxide fuel cell (SOFC). The transport properties of the anode and cathode have a significant influence on the electrochemical performance of a fuel cell stack and therefore represent an important parameter when designing fuel cell stacks. In order to determine the transport parameters of the cathode layers in a fabricated SOFC, it is necessary to permeate the thin cathode layer deposited on the gas-tight electrolyte with a defined gas transport. These thin cathode layers cannot be fabricated as mechanically stable single layers and cannot therefore be investigated in the diffusion and permeation experiments usually used to determine transport parameters. The setup of these experiments - particularly the sample holder - was therefore altered in this work. The result of this altered setup was a three-dimensional flow configuration. Compared to the conventional setup, it was no longer possible to describe the gas transport in the experiments with an analytical one-dimensional solution. A numerical solution process had to be used to evaluate the measurements. The new setup permitted a sufficiently symmetrical gas distribution and thus allowed the description of the transport to be reduced to a two-dimensional description, which significantly reduced the computational effort required to evaluate the measurements. For pressure-induced transport, a parametrized coherent expression of transport could be derived. This expression is equivalent to the analytical description of the transport in conventional measurement setups, with the exception of parameters that describe the geometry of the gas diffusion. In this case, a numerical process is not necessary for the evaluation. Using the transport parameters of mechanically stable anode substrates, which can be measured both in the old and the new setups, the old and

  6. Organic electrolyte-based rechargeable zinc-ion batteries using potassium nickel hexacyanoferrate as a cathode material

    Science.gov (United States)

    Chae, Munseok S.; Heo, Jongwook W.; Kwak, Hunho H.; Lee, Hochun; Hong, Seung-Tae

    2017-01-01

    This study demonstrates an organic electrolyte-based rechargeable zinc-ion battery (ZIB) using Prussian blue (PB) analogue potassium nickel hexacyanoferrate K0.86Ni[Fe(CN)6]0.954(H2O)0.766 (KNF-086) as the cathode material. KNF-086 is prepared via electrochemical extraction of potassium ions from K1.51Ni[Fe(CN)6]0.954(H2O)0.766 (KNF-151). The cell is composed of a KNF-086 cathode, a zinc metal anode, and a 0.5 M Zn(ClO4)2 acetonitrile electrolyte. This cell shows a reversible discharge capacity of 55.6 mAh g-1 at 0.2 C rate with the discharge voltage at 1.19 V (vs. Zn2+/Zn). As evidenced by Fourier electron density analysis with powder XRD data, the zinc-inserted phase is confirmed as Zn0.32K0.86Ni[Fe(CN)6]0.954(H2O)0.766 (ZKNF-086), and the position of the zinc ion in ZKNF-086 is revealed as the center of the large interstitial cavities of the cubic PB. Compared to KNF-086, ZKNF-086 exhibits a decreased unit cell parameter (0.9%) and volume (2.8%) while the interatomic distance of d(Fe-C) increased (from 1.84 to 1.98 Å), and the oxidation state of iron decreases from 3 to 2.23. The organic electrolyte system provides higher zinc cycling efficiency (>99.9%) than the aqueous system (ca. 80%). This result demonstrates an organic electrolyte-based ZIB, and offers a crucial basis for understanding the electrochemical intercalation chemistry of zinc ions in organic electrolytes.

  7. Performance equations for cathodes in polymer electrolyte fuel cells with non-uniform water flooding in gas diffusers

    Science.gov (United States)

    Hsuen, Hsiao-Kuo

    The performance equations for cathodes of polymer electrolyte fuel cells (PEFCs) that describe the dependence of cathode potential on current density are developed. Formulation of the performance equations starts from the reduction of a one-dimensional model that considers, in detail, the potential losses pertinent to the limitations of electron conduction, oxygen diffusion, proton migration, and the oxygen reduction reaction. In particular, non-uniform accumulation of liquid water in the gas diffuser, which partially blocks the gas channels and imposes a greater resistance for oxygen transport, is taken into account. Reduction of the one-dimensional model is implemented by approximating the oxygen concentration profile in the catalyst layer with a parabolic polynomial or a piecewise parabolic one determined by the occurrence of oxygen depletion. The final forms of the equations are obtained by applying the method of weighted residuals over the catalyst layer. The weighting function is selected in such a way that the weighted residuals can be analytically integrated. Potential losses caused by the various limiting processes can be quantitatively estimated by the performance equations. Thus, they provide a convenient diagnostic tool for the cathode performance. Computational results reveal that the performance equations agree well with the original one-dimensional model over an extensive range of parameter values. This indicates that the present performance equations can be used as a substitute for the one-dimensional model to provide quantitatively correct predictions for the cathode performance of PEFCs.

  8. La2Zr2O7 TBCs toughened by Pt particles prepared by cathode plasma electrolytic deposition

    Science.gov (United States)

    Deng, Shun-jie; Wang, Peng; He, Ye-dong; Zhang, Jin

    2016-06-01

    La2Zr2O7 thermal barrier coatings (TBCs) with dispersed Pt particles were prepared by cathode plasma electrolytic deposition (CPED) with ceramic balls added to the cathode region. Compared with the conventional CPED, when ceramic balls are used in the cathode region, the plasma discharge ignition current density decreases approximately 62-fold and the stable plasma discharges occur at the whole cathode surface. Such TBCs with a thickness of 100 μm exhibit a crack-free surface and are composed of pyrochlore-structured La2Zr2O7. Cyclic oxidation, scratching, and thermal insulation capability tests show that such TBCs not only exhibit high resistance to oxidation and spallation but also provide good thermal insulation. These beneficial effects are attributed to the excellent properties of TBCs, such as good thermal insulation because of low thermal conductivity, high-temperature oxidation resistance because of low-oxygen diffusion rate, and good mechanical properties because of the toughening effect of Pt particles.

  9. Rechargeable lithium battery using non-flammable electrolyte based on tetraethylene glycol dimethyl ether and olivine cathodes

    Science.gov (United States)

    Di Lecce, Daniele; Carbone, Lorenzo; Gancitano, Vincenzo; Hassoun, Jusef

    2016-12-01

    We propose lithium metal cells employing LiCF3SO3-tetraethylene glycol dimethy ether (TEGDME) electrolyte solution with LiFePO4 and LiMn0.5Fe0.5PO4 cathodes. The electrolyte is selected due to its non-flammability, herein demonstrated, and considered as a key requirement for application cells employing high energy lithium metal anode. The selected olivine cathodes, i.e., stable materials prepared by solvothermal pathway, have regular submicrometrical morphology suitable for cell operation and homogeneous composition, as confirmed by electron microscopy and energy dispersive X-ray spectroscopy. The electrochemical tests reveal promising cycling performances in terms of delivered capacity, stability and rate capability. The Li/LiCF3SO3-TEGDME/LiFePO4 cell operates at 3.5 V with capacity ranging from 150 mAh g-1 at C/10 to 110 mAh g-1 at 2C, while the Li/LiCF3SO3-TEGDME/LiFe0.5Mn0.5PO4 cell performs following two plateaus at 4.1 V and 3.5 V with capacity ranging from 160 mAh g-1 at C/10 to 75 mAh g-1 at 2C. Hence, the results demonstrate the suitability of TEGDME-based electrolytes in combination with LiFePO4 and LiFe0.5Mn0.5PO4 cathodes for high performances lithium battery.

  10. Numerical predictions and experimental verification of Li-O2 battery capacity limits for cathodes with spherical conductors and solid electrolytes

    Science.gov (United States)

    Lee, Heung Chan; Roev, Victor; Kim, Tae Young; Park, Min Sik; Lee, Dong Joon; Im, Dongmin; Doo, Seok-Gwang

    2016-11-01

    The capacity limits, local formation of Li2O2, passivation of active surfaces, and depletion of oxygen by mass transport characteristics in a composite cathode are modeled, numerically simulated, and experimentally evaluated for non-aqueous Li-O2 batteries employing composites of a solid polymer electrolyte and carbon particles as the cathode, Li metal as the anode, and an ion conductive oxide membrane as the separator. Although the theoretical maximum specific energy of the Li-O2 battery is known to be 3458 Wh kg-1cathode, our simulation predicts a maximum specific energy of 1840 Wh kg-1cathode with an optimized weight ratio of all essential components as well as cathode thickness. A specific energy of 1713 Wh kg-1cathode is experimentally demonstrated in a cell with a composite cathode of poly(ethylene oxide) electrolyte and Printex carbon nanoparticles with 48% carbon volume and 30 μm thickness. The model also predicts that the incorporation of voids in the cathode can significantly improve the specific energy.

  11. Relationship Between Designed Three-Dimensional YSZ Electrolyte Surface Area and Performance of Solution-Precursor Plasma-Sprayed La0.8Sr0.2MnO3- δ Cathodes

    Science.gov (United States)

    Zhang, Shan-Lin; Huang, Jiang-Yuan; Li, Cheng-Xin; Yang, Guan-Jun; Li, Chang-Jiu

    2016-12-01

    Active three-phase boundaries (TPBs) significantly influence cathode performance in solid oxide fuel cells, but obtaining long TPBs and understanding the mechanism underlying the improved cathode performance when the electrolyte is prepared with a smooth surface by a high-temperature sintering process remain essential challenges. In this work, we used flame spraying to deposit single-layer semimolten particles on a smooth electrolyte to build a three-dimensional surface with enlarged active surface area and thus increased TPBs. Meanwhile, La0.8Sr0.2MnO3- δ (LSM) cathodes with fine microstructure were deposited by solution-precursor plasma spraying (SPPS) on the designed electrolyte to establish a three-dimensional cathode-electrolyte interface. The deposition behavior of the semimolten particles on the smooth electrolyte and LSM cathodes on the three-dimensional electrolyte surface was studied. The effects of the area enlargement factor ( α area) on the polarization resistance of the SPPS LSM cathodes were investigated, using three-dimensional electrolytes with α area from 1.29 to 2.48. The results indicated that convex particles with different molten states bonded well with the electrolytes. SPPS LSM cathodes also showed good interfacial bonding with convex particles. Finally, the cathode polarization ( R p) decreased linearly with increase of α area. At 800 °C, R p decreased from 0.98 to 0.32 Ω cm2 when α area was increased from 1.29 to 2.48.

  12. Metallization pattern on solid electrolyte or porous support of sodium battery process

    Science.gov (United States)

    Kim, Jin Yong; Li, Guosheng; Lu, Xiaochuan; Sprenkle, Vincent L.; Lemmon, John P.

    2016-05-31

    A new battery configuration and process are detailed. The battery cell includes a solid electrolyte configured with an engineered metallization layer that distributes sodium across the surface of the electrolyte extending the active area of the cathode in contact with the anode during operation. The metallization layer enhances performance, efficiency, and capacity of sodium batteries at intermediate temperatures at or below about 200.degree. C.

  13. Electrolytic oxygen generation for subsurface delivery: effects of precipitation at the cathode and an assessment of side reactions.

    Science.gov (United States)

    Franz, Jeffrey A; Williams, Rucker J; Floraa, Joseph R V; Meadows, Michael E; Irwin, Walter G

    2002-05-01

    This research investigated the oxygen-generating characteristics and side reactions of an electrolytic cell assembly that could be used to remediate sites with contaminants that are amenable to aerobic biodegradation. The oxygen-generating capabilities of new electrolytic cells and cells with light and heavy calcium carbonate precipitates on the cathode were evaluated in the laboratory under current densities ranging from 0.5 to 5.0 mA/cm2. Higher current densities resulted in higher mass transfer coefficients (K(L)a) and greater saturation oxygen concentrations (Csat). As the cathodic deposits increased, the K(L)a tended to decrease and the Csat tended to increase. The oxygen transfer efficiency (OTE) did not vary as a function of current density or cathode coating, while the average OTE for all the tests was 67%. Laboratory column tests showed that chlorine production increased with current density and depended on chloride levels in the water. Hydrogen peroxide was generated at low concentrations (< 1 mg/L) and at higher levels when chloride was absent in the feed solution. Calcium removal from solution increased with current density and resulted in a decrease in solution pH. Tests at a field monitoring well showed average Csat levels of 16.9 mg/L after 14 days of operation, no chlorine production because of low chloride levels in the well, artificially elevated hydrogen peroxide levels because of background interferences, and a pH decrease of 2.4 units. With passive venting, the average hydrogen gas levels at the headspace of the well were less than 1%.

  14. Electrolytes as Cathode Interlayers in Inverted Organic Solar Cells: Influence of the Cations on Bias-Dependent Performance.

    Science.gov (United States)

    Li, Yaru; Liu, Xiaohui; Li, Xiaodong; Zhang, Wenjun; Xing, Feifei; Fang, Junfeng

    2017-02-24

    The performance of organic solar cells (OSCs) with edetate electrolytes depends on external bias, and ions are speculated to be responsible for this phenomenon. To clarify the detailed relationship between the ions of electrolytes and the bias-dependent behaviors of devices, this work introduces four edetate cathode interlayers (EDTA-X, X = nH(4-n)Na, n = 0, 1, 2, and 4) containing different kinds and number of cations into inverted OSCs. The results show that the devices initial and saturated (after external bias treatment) power conversion efficiencies (PCEs) both decrease with the increase in the number of H(+). Moreover, the bias-dependent degrees increase with the increase in H(+) number; with that, the PCE increment of EDTA-4H device is 53.4%, while that of the EDTA-4Na device is almost unchanged. The electrical impedance spectroscopy and capacitance-voltage tests reveal that the interfacial recombination is greatly suppressed by external bias treatment, which is not a result of the decreased density of defect states. The results indicate that the ion's motion, specifically the H(+) motion, under external electrical field is responsible for the bias-dependent behavior, which is conducive to the design of new efficient electrolytic interlayers without bias-dependent performance.

  15. 4-(Trifluoromethyl)-benzonitrile: A novel electrolyte additive for lithium nickel manganese oxide cathode of high voltage lithium ion battery

    Science.gov (United States)

    Huang, Wenna; Xing, Lidan; Wang, Yating; Xu, Mengqing; Li, Weishan; Xie, Fengchao; Xia, Shengan

    2014-12-01

    In this work, 4-(Trifluoromethyl)-benzonitrile (4-TB) is used as a novel electrolyte additive for LiNi0.5Mn1.5O4 cathode of high voltage lithium ion battery. Charge-discharge tests show that the cyclic stability of LiNi0.5Mn1.5O4 is significantly improved by using 0.5 wt.% 4-TB. With using 4-TB, LiNi0.5Mn1.5O4 delivers an initial capacity of 133 mAh g-1 and maintains 121 mAh g-1 after 300 cycles with a capacity retention of 91%, compared to the 75% of that using base electrolyte (1 M LiPF6 in ethylene carbonate(EC)/dimethyl carbonate(DMC)). The results from linear sweep voltammetry, density functional theory calculations, electrochemical impedance spectroscopy, scanning electron microscope, energy dispersive spectroscopy, Fourier transform infrared, and inductively coupled plasma, indicate that 4-TB has lower oxidative stability than EC and DMC, and is preferentially oxidized on LiNi0.5Mn1.5O4 forming a low-impedance protective film, which prevents the subsequent oxidation decomposition of the electrolyte and suppresses the manganese dissolution from LiNi0.5Mn1.5O4.

  16. Advances in Ceramic Supports for Polymer Electrolyte Fuel Cells

    Directory of Open Access Journals (Sweden)

    Oran Lori

    2015-08-01

    Full Text Available Durability of catalyst supports is a technical barrier for both stationary and transportation applications of polymer-electrolyte-membrane fuel cells. New classes of non-carbon-based materials were developed in order to overcome the current limitations of the state-of-the-art carbon supports. Some of these materials are designed and tested to exceed the US DOE lifetime goals of 5000 or 40,000 hrs for transportation and stationary applications, respectively. In addition to their increased durability, the interactions between some new support materials and metal catalysts such as Pt result in increased catalyst activity. In this review, we will cover the latest studies conducted with ceramic supports based on carbides, oxides, nitrides, borides, and some composite materials.

  17. Effects of laminating and co-firing conditions on the performance of anode-supported Ce0.8Sm0.201.9 film electrolyte

    Directory of Open Access Journals (Sweden)

    Li X.

    2011-01-01

    Full Text Available In order to evaluate the laminating and co-firing technique on the performance of anode-supported Ce0.8Sm0.2O1.9 (SDC film electrolyte and its single cell, NiO-YSZ and NiOSDC anode-supported SDC film electrolytes were fabricated by laminating 24 sheets of anode plus one sheet of electrolyte and co-firing. La0.4Sr0.6Co0.2Fe0.8O3-δ (LSCF-SDC cathode was coated on the SDC electrolytes to form a single cell. The lamination was tried at different laminating temperatures and pressures and the co-firing was carried out at different temperatures. The results showed that the laminating temperature should above the glass transition temperature (Tg of the binder. The laminating pressure of 70 MPa resulted in warp of the samples. The best co-firing temperature of the anode-supported SDC film electrolyte was 1400°C. The SDC film electrolyte formed well adherence to the anode. The NiO-YSZ anode had larger flexural strength than the NiO-SDC anode. The NiO-YSZ anode-supported SDC film electrolyte single cell had an open circuit voltage of 0.803 V and a maximum power density of 93.03 mW/cm2 with hydrogen as fuel at 800°C.

  18. LaCoO3: Promising cathode material for protonic ceramic fuel cells based on a BaCe0.2Zr0.7Y0.1O3−δ electrolyte

    DEFF Research Database (Denmark)

    Ricote, Sandrine; Bonanos, Nikolaos; Lenrick, Filip;

    2012-01-01

    Symmetric cells (cathode/electrolyte/cathode) were prepared using BaCe0.2Zr0.7Y0.1O3−δ (BCZY27) as proton conducting electrolyte and LaCoO3 (LC) infiltrated into a porous BCZY27 backbone as cathode. Single phased LC was formed after annealing in air at 600 °C for 2 h. Scanning electron micrographs...

  19. Performance evaluation of printed LiCoO{sub 2} cathodes with PVDF-HFP gel electrolyte for lithium ion microbatteries

    Energy Technology Data Exchange (ETDEWEB)

    Park, Moon-Soo [School of Advanced Materials Science and Engineering, College of Engineering, Yonsei University, Seoul 120-749 (Korea); Samsung Electro-Mechanics Maetan-3-dong, YeongTong-gu, Suwon City, Gyeonggi Province 442-743 (Korea); Hyun, Sang-Hoon [School of Advanced Materials Science and Engineering, College of Engineering, Yonsei University, Seoul 120-749 (Korea); Nam, Sang-Cheol [Nuricell Inc., 4F, GS Caltex New Energy Development Center, 453-2, Seongnae-dong, Gangdong-gu, Seoul 134-030 (Korea); Cho, Sung Back [Advanced Technology Research Center, Agency for Defense Development, Daejeon 305-600 (Korea)

    2008-07-01

    In order to improve the discharge capacity in lithium ion microbatteries, a thick-film cathode was fabricated by a screen printing using LiCoO{sub 2} pastes. The printed cathode showed a different discharge curves when the cell was tested using various (liquid, gel and solid-state) electrolytes. When a cell test was performed with organic liquid electrolyte, the maximum discharge capacity was 200 {mu}Ah cm{sup -2}, which corresponded to approximately 133 mAh g{sup -1} when the loading weight of LiCoO{sub 2} was calculated. An all-solid-state microbattery could be assembled using sputtered LiPON electrolyte, an evaporated Li anode, and printed LiCoO{sub 2} cathode films without delamination or electrical problems. However, the highest discharge capacity showed a very small value (7 {mu}Ah cm{sup -2}). This problem could be improved using a poly(vinylidene fluoride-hexafluoro propylene) (PVDF-HFP) gel electrolyte, which enhanced the contact area and adhesion force between cathode and electrolyte. The discharge value of this cell was measured as approximately 164 {mu}Ah cm{sup -2} ({approx}110 mAh g{sup -1}). As the PVDF-HFP electrolyte had a relatively soft contact property with higher ionic conductance, the cell performance was improved. In addition, the cell can be fabricated in a leakage-free process, which can resolve many safety problems. According to these results, there is a significant possibility that a film prepared using the aforementioned paste with screen printing and PVDF-HFP gel electrolyte is feasible for a microbattery. (author)

  20. Anode Supported Solid Oxide Fuel Cells - Deconvolution of Degradation into Cathode and Anode Contributions

    DEFF Research Database (Denmark)

    Hagen, Anke; Liu, Yi-Lin; Barfod, Rasmus;

    2007-01-01

    The degradation of anode supported cells was studied over 1500 h as function of cell polarization either in air or oxygen on the cathode. Based on impedance analysis, contributions of anode and cathode to the increase of total resistance were assigned. Accordingly, the degradation rates of the ca...

  1. An Artificial SEI Enables the Use of A LiNi0.5Mn1.5O4 5 V Cathode with Conventional Electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Li, Juchuan [ORNL; Baggetto, Loic [ORNL; Martha, Surendra K [ORNL; Veith, Gabriel M [ORNL; Nanda, Jagjit [ORNL; Liang, Chengdu [ORNL; Dudney, Nancy J [ORNL

    2013-01-01

    LiNi0.5Mn1.5O4 spinel is considered one of the most promising cathodes for advanced lithium ion batteries. However, the operation potential of LiNi0.5Mn1.5O4, ~4.75 V, is beyond the high voltage limit of the state-of-art electrolyte, ~4.3 V. Here, using thin films of LiNi0.5Mn1.5O4 as a model material, we show evidence that an artificial solid electrolyte interphase (SEI) enables the use of this 5 V cathode with conventional carbonate electrolytes. A thin coating of Lipon (lithium phosphorus oxynitride) as an artificial SEI on LiNi0.5Mn1.5O4 could remedy the decomposition of the electrolyte. The thickness of the Lipon artificial SEI is optimized by balancing the protection and additional resistance. The strategy of artificial SEI on cathodes is expected to enable the wide application of other high voltage cathodes for lithium ion batteries.

  2. Titanium-Niobium Oxides as Non-Noble Metal Cathodes for Polymer Electrolyte Fuel Cells

    OpenAIRE

    Akimitsu Ishihara; Yuko Tamura; Mitsuharu Chisaka; Yoshiro Ohgi; Yuji Kohno; Koichi Matsuzawa; Shigenori Mitsushima; Ken-ichiro Ota

    2015-01-01

    In order to develop noble-metal- and carbon-free cathodes, titanium-niobium oxides were prepared as active materials for oxide-based cathodes and the factors affecting the oxygen reduction reaction (ORR) activity were evaluated. The high concentration sol-gel method was employed to prepare the precursor. Heat treatment in Ar containing 4% H2 at 700–900 °C was effective for conferring ORR activity to the oxide. Notably, the onset potential for the ORR of the catalyst prepared at 700 °C was a...

  3. Porous-Al2O3 thermal barrier coatings with dispersed Pt particles prepared by cathode plasma electrolytic deposition

    Institute of Scientific and Technical Information of China (English)

    Jin Zhang

    2016-01-01

    Porousa-Al2O3 thermal barrier coatings (TBCs) containing dispersed Pt particles were prepared by cathode plasma electrolytic deposition (CPED). The influence of the Pt particles on the microstructure of the coatings and the CPED process were studied. The prepared coatings were mainly composed ofα-Al2O3. The average thickness of the coatings was approximately 100μm. Such single-layer TBCs ex-hibited not only excellent high-temperature cyclic oxidation and spallation resistance, but also good thermal insulation properties. Porousa-Al2O3 TBCs inhibit further oxidation of alloy substrates because of their extremely low oxygen diffusion rate, provide good thermal insu-lation because of their porous structure, and exhibit excellent mechanical properties because of the toughening effect of the Pt particles and because of stress relaxation induced by deformation of the porous structure.

  4. Electrochemical Impedance Studies of SOFC Cathodes

    DEFF Research Database (Denmark)

    Hjelm, Johan; Søgaard, Martin; Wandel, Marie

    2007-01-01

    impedance of the cathode at intermediate operating temperatures. The perovskite is of the La-Sr-Co-Fe type. The EIS response of symmetrical cells with a thick (similar to 200 mu m) gadolinia doped ceria electrolyte was compared with the impedance contribution of the cathode of a full anode supported cell....... The full cells had a Ni-YSZ anode and anode support, a thin YSZ electrolyte, and a CGO barrier layer. The symmetric and full cell cathode responses were compared at open-circuit voltage. Humidified hydrogen was used as the fuel in the full cell measurements. Differential analysis of the impedance data...

  5. A method for making an active cathode mass for an element with a liquid, anhydrous electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Indzima, T.; Morita, A.

    1983-07-14

    Powder of fluorinated carbon, produced as a result of a reaction between gaseous F2 and carbon powder in the presence of gaseous 02, is used as the active cathode mass in the element. The bulk volume of 02 is 3 percent with respect to the gaseous F2. The element with the lithium anode has good discharge characteristics.

  6. A novel lithium/sulfur battery based on sulfur/graphene nanosheet composite cathode and gel polymer electrolyte.

    Science.gov (United States)

    Zhang, Yongguang; Zhao, Yan; Bakenov, Zhumabay

    2014-03-21

    A novel sulfur/graphene nanosheet (S/GNS) composite was prepared via a simple ball milling of sulfur with commercial multi-layer graphene nanosheet, followed by a heat treatment. High-resolution transmission and scanning electronic microscopy observations showed the formation of irregularly interlaced nanosheet-like structure consisting of graphene with uniform sulfur coating on its surface. The electrochemical properties of the resulting composite cathode were investigated in a lithium cell with a gel polymer electrolyte (GPE) prepared by trapping 1 mol dm-3 solution of lithium bistrifluoromethanesulfonamide in tetraethylene glycol dimethyl ether in a polymer matrix composed of poly(vinylidene fluoride-co-hexafluoropropylene)/poly(methylmethacrylate)/silicon dioxide (PVDF-HFP/PMMA/SiO2). The GPE battery delivered reversible discharge capacities of 809 and 413 mAh g-1 at the 1st and 50th cycles at 0.2C, respectively, along with a high coulombic efficiency over 50 cycles. This performance enhancement of the cell was attributed to the suppression of the polysulfide shuttle effect by a collective effect of S/GNS composite cathode and GPE, providing a higher sulfur utilization.

  7. A novel lithium/sulfur battery based on sulfur/graphene nanosheet composite cathode and gel polymer electrolyte

    Science.gov (United States)

    Zhang, Yongguang; Zhao, Yan; Bakenov, Zhumabay

    2014-03-01

    A novel sulfur/graphene nanosheet (S/GNS) composite was prepared via a simple ball milling of sulfur with commercial multi-layer graphene nanosheet, followed by a heat treatment. High-resolution transmission and scanning electronic microscopy observations showed the formation of irregularly interlaced nanosheet-like structure consisting of graphene with uniform sulfur coating on its surface. The electrochemical properties of the resulting composite cathode were investigated in a lithium cell with a gel polymer electrolyte (GPE) prepared by trapping 1 mol dm-3 solution of lithium bistrifluoromethanesulfonamide in tetraethylene glycol dimethyl ether in a polymer matrix composed of poly(vinylidene fluoride-co-hexafluoropropylene)/poly(methylmethacrylate)/silicon dioxide (PVDF-HFP/PMMA/SiO2). The GPE battery delivered reversible discharge capacities of 809 and 413 mAh g-1 at the 1st and 50th cycles at 0.2C, respectively, along with a high coulombic efficiency over 50 cycles. This performance enhancement of the cell was attributed to the suppression of the polysulfide shuttle effect by a collective effect of S/GNS composite cathode and GPE, providing a higher sulfur utilization. PACS: 82.47.Aa; 82.45.Gj; 62.23.Kn

  8. Advancing Polymer-Supported Ionogel Electrolytes Formed via Radical Polymerization

    Science.gov (United States)

    Visentin, Adam F.

    Applications ranging from consumer electronics to the electric grid have placed demands on current energy storage technologies. There is a drive for devices that store more energy for rapid consumption in the case of electric cars and the power grid, and safer, versatile design options for consumer electronics. Electrochemical double-layer capacitors (EDLCs) are an option that has garnered attention as a means to address these varied energy storage demands. EDLCs utilize charge separation in electrolytes to store energy. This energy storage mechanism allows for greater power density (W kg -1) than batteries and higher energy density (Wh kg-1) than conventional capacitors - along with a robust lifetime in the range of thousands to millions of charge-discharge cycles. Safety and working voltage windows of EDLCs currently on the market are limited by the organic solvents utilized in the electrolyte. A potential solution lies in the replacement of the organic solvents with ionic liquids, or room-temperature molten salts. Ionic liquids possess many superior properties in comparison to conventional solvents: wide electrochemical window, low volatility, nonflammability, and favorable ionic conductivity. It has been an endeavor of this work to exploit these advantages while altering the liquid form factor into a gel. An ionic liquid/solid support scaffold composite electrolyte, or ionogel, adds additional benefits: flexible device design, lower encapsulation weight, and elimination of electrolyte leakage. This work has focused on investigations of a UV-polymerizable monomer, poly(ethylene glycol) diacrylate, as a precursor for forming ionogels in situ. The trade-off between gaining mechanical stability at the cost of ionic conductivity has been investigated for numerous ionogel systems. While gaining a greater understanding of the interactions between the gel scaffold and ionic liquid, an ionogel with the highest known ionic conductivity to date (13.1 mS cm-1) was

  9. Two-phase flow modeling for the cathode side of a Polymer electrolyte fuel cell

    NARCIS (Netherlands)

    Qin, C.; Rensink, D.; Fell, S.; Hassanizadeh, S.M.

    2012-01-01

    Liquid water flooding in micro gas channels is an important issue in the water management of polymer electrolyte fuel cells (PEFCs). However, in most previous numerical studies liquid water transport in the gas channels (GC) has been simplified by the mist flow assumption. In this work, we present a

  10. A perspective on coatings to stabilize high-voltage cathodes: LiMn1.5Ni0.5O4 with subnanometer Lipon cycled with LiPF6 electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yoongu [ORNL; Dudney, Nancy J [ORNL; Chi, Miaofang [ORNL; Martha, Surendra K [ORNL; Nanda, Jagjit [ORNL; Veith, Gabriel M [ORNL; Liang, Chengdu [ORNL

    2013-01-01

    High voltage Li-ion cathodes push the limits of stability for both cathode and electrolyte. Here subnanometer coatings of an amorphous thin film electrolyte (Lipon) improved the room temperature and 60 C cycling stability of a LiMn1.5Ni0.5O4 spinel cathode when charged to 4.9V with a standard LiPF6 carbonate electrolyte. The cathodes delivered superior C-rate performances up to a 5C discharge, when compared to the uncoated cathodes. Enhanced performance extended for at least 100 cycles. Electrochemical impedance spectroscopy indicates that Lipon slows the increase of interface resistance. Thicker 1-3nm Lipon coatings are sufficiently insulating as to block electronic transport to the cathode particles. Thick coatings also slow Mn dissolution. Results suggest that Lipon may act to scavenge impurities or block active sites that promote electrolyte decomposition. While greatly improved by the Lipon coating, this cathode is not sufficiently stable for long cycle life applications. Further work is needed to assess if and what surface coatings will ultimately stabilize the high voltage cathodes. Comments include insight from other studies of Lipon coated cathodes and directions for future research.

  11. Titanium-Niobium Oxides as Non-Noble Metal Cathodes for Polymer Electrolyte Fuel Cells

    Directory of Open Access Journals (Sweden)

    Akimitsu Ishihara

    2015-07-01

    Full Text Available In order to develop noble-metal- and carbon-free cathodes, titanium-niobium oxides were prepared as active materials for oxide-based cathodes and the factors affecting the oxygen reduction reaction (ORR activity were evaluated. The high concentration sol-gel method was employed to prepare the precursor. Heat treatment in Ar containing 4% H2 at 700–900 °C was effective for conferring ORR activity to the oxide. Notably, the onset potential for the ORR of the catalyst prepared at 700 °C was approximately 1.0 V vs. RHE, resulting in high quality active sites for the ORR. X-ray (diffraction and photoelectron spectroscopic analyses and ionization potential measurements suggested that localized electronic energy levels were produced via heat treatment under reductive atmosphere. Adsorption of oxygen molecules on the oxide may be governed by the localized electronic energy levels produced by the valence changes induced by substitutional metal ions and/or oxygen vacancies.

  12. Electrodeposited synthesis of self-supported Ni-P cathode for efficient electrocatalytic hydrogen generation

    Institute of Scientific and Technical Information of China (English)

    Ruixian Wu; Yuming Dong n; Pingping Jiang; Guangli Wang; Yanmei Chen; Xiuming Wu

    2016-01-01

    One of the key challenges for electrochemical water splitting is the development of low-cost and efficient hydrogen evolution cathode. In this work, a self-supported Ni-P cathode was synthesized by a facile electrodeposition method. The composition and morphology were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy. The Ni-P cathode performed low onset over-potential, good catalytic activity and long-term stability under neutral and alkaline conditions. The mechanism of Ni-P electrode for hydrogen production was discussed by electrochemical impedance spectroscopy. The excellent performance of Ni-P cathode was mainly attributed to the synergistic effect of phosphate anions and the self-supported feature.

  13. Electrodeposited synthesis of self-supported Ni-P cathode for efficient electrocatalytic hydrogen generation

    Directory of Open Access Journals (Sweden)

    Ruixian Wu

    2016-06-01

    Full Text Available One of the key challenges for electrochemical water splitting is the development of low-cost and efficient hydrogen evolution cathode. In this work, a self-supported Ni-P cathode was synthesized by a facile electrodeposition method. The composition and morphology were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy. The Ni-P cathode performed low onset over-potential, good catalytic activity and long-term stability under neutral and alkaline conditions. The mechanism of Ni-P electrode for hydrogen production was discussed by electrochemical impedance spectroscopy. The excellent performance of Ni-P cathode was mainly attributed to the synergistic effect of phosphate anions and the self-supported feature.

  14. Electrochemical impedance study and performance of PdNi nanoparticles as cathode catalyst in a polymer electrolyte membrane fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Ramos-Sanchez, G.; Santana-Salinas, A.; Vazquez-Huerta, G.; Solorza-Feria, O. [Inst. Politenico Nacional, Centro de Investigacion y de Estudios Avanzados, Mexico City (Mexico). Dept. de Quimica

    2010-07-15

    Polymer electrolyte membrane fuel cells (PEMFC) convert the energy stored in hydrogen and oxygen molecules directly into electricity. However, technical and economic challenges must be overcome to address cost, performance and stability issues associated with membrane electrode assemblies (MEA). The oxygen reduction reaction (ORR) which takes place in the cathode is the limiting reaction due to the slow kinetics of ORR on metals, including platinum (Pt). For that reason, much research has gone into finding catalyst materials with a similar or greater performance than Pt. Bimetallic palladium (Pd) based catalysts have been considered as alternative materials for ORR. In this study, a carbon-dispersed bimetallic PdNi was prepared by borohydride reduction using PdCl{sub 2} and NiCl{sub 2} as precursors in a tetrahydrofuran (THF) solution. The PdNi loading and weight percentage were optimized using the Simplex method. The MEA performance was evaluated at optimum conditions using the PdNi electrocatalyst as the cathode and a Pt-Etek carbon cloth as the anode. The maximum power density of 122 mW per cm{sup 2} was reached with 45 percent of PdNi wt percent at 30 psi and 80 degrees C. The catalytic activity and the mechanism of the ORR on PdNi, in 0.5M H{sub 2}SO{sub 4} was investigated using electrochemical impedance spectroscopy. The Tafel slope and the charge transfer coefficient were obtained from the impedance spectra at optimum condition of PdNi loading and PdNi wt percent. 24 refs., 2 tabs., 5 figs.

  15. Influence of carbon monoxide on the cathode in high-temperature polymer electrolyte membrane fuel cells

    DEFF Research Database (Denmark)

    Søndergaard, Stine; Cleemann, Lars Nilausen; Jensen, J. O.

    2017-01-01

    This paper describes the results of adding small amounts of CO gas to the cathode side in a HT-PEM fuel cell with a polybenzimidazole (PBI) membrane running on either oxygen or air. Experimental conditions: Temperature ranges 120–160 °C, constant current either 200 mA/cm2 or 800 mA/cm2 and CO...... ranges 0.1–1.3%. In this case it was found that small amounts of CO under special conditions have a beneficial effect on the potential of the fuel cells, whereas larger amounts can bring the potential down to almost zero. An interesting phenomenon is that after the flow of CO is switched off a temporary...

  16. High Performance Infiltrated Backbones for Cathode-Supported SOFC's

    DEFF Research Database (Denmark)

    Gil, Vanesa; Kammer Hansen, Kent

    2014-01-01

    A four-step infiltration method has been developed to infiltrate La0.75Sr0.25MnO3+δ (LSM25) nanoparticles into porous structures (YSZ or LSM-YSZ backbones). The pore size distribution in the backbones is obtained either by using PMMA and/or graphites as pore formers or by leaching treatment of sa...... of samples with Ni remained in the YSZ structure at high temperatures. All impregnated backbones, presented Rs comparable to a standard screen printed cathode, which proves that LSM nanoparticles forms a pathway for electron conduction....

  17. An experimental and simulation study of novel channel designs for open-cathode high-temperature polymer electrolyte membrane fuel cells

    DEFF Research Database (Denmark)

    Thomas, Sobi; Bates, Alex; Park, Sam

    2016-01-01

    A minimum balance of plant (BOP) is desired for an open-cathode high temperature polymer electrolyte membrane (HTPEM) fuel cell to ensure low parasitic losses and a compact design. The advantage of an open-cathode system is the elimination of the coolant plate and incorporation of a blower...... distribution through each cell. Design studies were carried out to increase power density. An experimental and simulation approach was carried out to design the novel open-cathode system. Two unique parallel serpentine flow designs were developed to yield a low pressure drop and uniform flow distribution, one...... without pins and another with pins. A five-cell stack was fabricated in the lab based on the new design. Performance and flow distribution studies revealed better performance, uniform flow distribution, and a reduced temperature gradient across the stack; improving overall system efficiency....

  18. In-situ neutron diffraction study of cathode/electrolyte interactions under electrical load and elevated temperature

    Science.gov (United States)

    Tonus, F.; Skinner, S. J.

    2016-05-01

    Fuel cells are proposed as a future energy conversion technology that will reduce greenhouse gas emissions at the point of operation due to their ability to produce electrical energy from non-hydrocarbon fuel sources. The Solid Oxide Fuel Cell (SOFC) is amongst the most efficient fuel cell types, however, due to the high cell operating temperature cation diffusion occurs between the different components of the cell, resulting in rapid degradation of the power output. In this paper we investigate cation migration between the promising intermediate temperature-SOFC cathode La1-xSrxCo1-yFeyO3-δ (LSCF) and a fluorite type electrolyte Ce1-xPrxO2-δ (CPO). The crystallographic structure evolution and degradation of the materials were studied by neutron diffraction in-situ under pseudo-operating conditions, i.e. at 600 °C under air and under electrical polarisation. The lattice parameter and cation occupancy evolution were analysed by Rietveld refinement as a function of time and applied potential. The materials were found to be stable, as no impurity formation, lattice parameter or site occupancy evolution was observed during the experiment. However La migration prior to the experiment from LSCF to CPO was observed as well as B-site vacancies in LSCF.

  19. Neutron scattering study on cathode LiMn2O4 and solid electrolyte 5(Li2O)(P2O5)

    Science.gov (United States)

    Kartini, E.; Putra, Teguh P.; Jahya, A. K.; Insani, A.; Adams, S.

    2014-09-01

    Neutron scattering is very important technique in order to investigate the energy storage materials such as lithium-ion battery. The unique advantages, neutron can see the light atoms such as Hydrogen, Lithium, and Oxygen, where those elements are negligible by other corresponding X-ray method. On the other hand, the energy storage materials, such as lithium ion battery is very important for the application in the electric vehicles, electronic devices or home appliances. The battery contains electrodes (anode and cathode), and the electrolyte materials. There are many challenging to improve the existing lithium ion battery materials, in order to increase their life time, cyclic ability and also its stability. One of the most scientific challenging is to investigate the crystal structure of both electrode and electrolyte, such as cathodes LiCoO2, LiMn2O4 and LiFePO4, and solid electrolyte Li3PO4. Since all those battery materials contain Lithium ions and Oxygen, the used of neutron scattering techniques to study their structure and related properties are very important and indispensable. This article will review some works of investigating electrodes and electrolytes, LiMn2O4 and 5(Li2O)(P2O5), by using a high resolution powder diffraction (HRPD) at the multipurpose research reactor, RSG-Sywabessy of the National Nuclear Energy Agency (BATAN), Indonesia.

  20. Interfacial characteristics of a PEGylated imidazolium bistriflamide ionic liquid electrolyte at a lithium ion battery cathode of LiMn2O4.

    Science.gov (United States)

    Rock, Simon E; Wu, Lin; Crain, Daniel J; Krishnan, Sitaraman; Roy, Dipankar

    2013-03-01

    Nonvolatile and nonflammable ionic liquids (ILs) have distinct thermal advantages over the traditional organic solvent electrolytes of lithium ion batteries. However, this beneficial feature of ILs is often counterbalanced by their high viscosity (a limiting factor for ionic conductivity) and, sometimes, by their unsuitable electrochemistry for generating protective layers on electrode surfaces. In an effort to alleviate these limiting aspects of ILs, we have synthesized a PEGylated imidazolium bis(trifluoromethylsulfonyl)amide (bistriflamide) IL that exhibited better thermal and electrochemical stability than a conventional electrolyte based on a blend of ethylene carbonate and diethyl carbonate. The electrochemical performance of this IL has been demonstrated using a cathode consisting of ball-milled LiMn2O4 particles. A direct comparison of the ionic liquid electrolyte with the nonionic low-viscosity conventional solvent blend is presented.

  1. The role of cathodic current in PEO of aluminum: Influence of cationic electrolyte composition on the transient current-voltage curves and the discharges optical emission spectra

    Science.gov (United States)

    Rogov, A. B.; Shayapov, V. R.

    2017-02-01

    In this paper, the influence of cationic electrolytes composition on electrical and optical responses of plasma electrolytic oxidation process of A1050 aluminum alloy under alternating polarization is considered. The electrolytes consist of 0.1 M boric acid with addition of one of the following hydroxides: LiOH, NaOH, KOH, tetraethylammonium hydroxide, Ca(OH)2 up to pH value 9.2. Coatings microstructure, elemental and phase compositions were studied by SEM, EDS and XRD. It was shown that the hysteresis of anodic current-voltage curve (specific feature of "Soft sparking" PEO) was clear observed in the presence of sodium and potassium cations. It was found that composition of microdischarges plasma is also affected by the nature of the cations. It was shown that there are a number of reciprocal processes, which take place under anodic and cathodic polarization.

  2. Electrochemical characterization of La0.6Ca0.4Fe0.8Ni0.2O3 cathode on Ce0.8Gd0.2O1.9 electrolyte for IT-SOFC

    DEFF Research Database (Denmark)

    Ortiz-Vitoriano, N.; Bernuy-Lopez, C.; Hauch, Anne;

    2014-01-01

    has shown potential as an intermediate temperature SOFC cathode. An equivalent circuit describing the cathode polarization resistances was constructed from analyzing impedance spectra recorded at different temperatures in oxygen. A competitive electrode polarization resistance is reported...... for this oxygen electrode using a Ce0.8Gd0.2O1.9 electrolyte, determined by impedance spectroscopy studies of symmetrical cells sintered at 800 _C and 1000 _C. Scanning electron microscopy (SEM) studies of the symmetrical cells revealed the absence of any reaction layer between cathode and electrolyte...

  3. Oxygen reduction on carbon supported platinum catalysts in high temperature polymer electrolytes

    DEFF Research Database (Denmark)

    Qingfeng, Li; Hjuler, Hans Aage; Bjerrum, Niels

    2000-01-01

    improve the oxygen reduction kinetics due to increased oxygen solubility and suppressed adsorption of phosphoric acid anions. Further enhancement of the catalytic activity can be obtained by operating the polymer electrolytes at higher temperatures. Efforts have been made to develop a polymer electrolyte......Oxygen reduction on carbon supported platinum catalysts has been investigated in H3PO4, H3PO4-doped Nafion and polybenzimidazole (PBI) polymer electrolytes in a temperature range up to 190 degrees C. Compared with pure H3PO4, the combination of H3PO4 and polymer electrolytes can significantly...

  4. New design of a cathode flow-field with a sub-channel to improve the polymer electrolyte membrane fuel cell performance

    Science.gov (United States)

    Wang, Yulin; Yue, Like; Wang, Shixue

    2017-03-01

    The cathode flow-field design of polymer electrolyte membrane (PEM) fuel cells determines the distribution of reactant gases and the removal of liquid water. A suitable design can result in perfect water management and thus high cell performance. In this paper, a new design for a cathode flow-field with a sub-channel was proposed and had been experimentally analyzed in a parallel flow-field PEM fuel cell. Three sub-channel inlets were placed along the cathode channel. The main-channel inlet was fed with moist air to humidify the membrane and maintain high proton conductivity, whereas, the sub-channel inlet was fed with dry air to enhance water removal in the flow channel. The experimental results indicated that the sub-channel design can decrease the pressure drop in the flow channel, and the sub-channels inlet positions (SIP, where the sub-channel inlets were placed along the cathode channel) and flow rates (SFR, percentage of air from the sub-channel inlet in the total cathode flow rate) had a considerable impact on water removal and cell performance. A proposed design that combines the SIP and SFR can effectively eliminate water from the fuel cell, increasing the maximum power density by more than 13.2% compared to the conventional design.

  5. Oxygen reduction on carbon supported platinum catalysts in high temperature polymer electrolytes

    DEFF Research Database (Denmark)

    Qingfeng, Li; Bergqvist, R. S.; Hjuler, H. A.

    1999-01-01

    Oxygen reduction on carbon supported platinum catalysts has been investigated in H3PO4, H3PO4-doped Nafion and PBI polymer electrolytes in a temperature range from 80 to 190°C. Compared with pure H3PO4, using the H3PO4 doped Nafion and PBI polymer electrolytes can significantly improve the oxygen...

  6. Effect of the state of distribution of supported Pt nanoparticles on effective Pt utilization in polymer electrolyte fuel cells.

    Science.gov (United States)

    Uchida, Makoto; Park, Young-Chul; Kakinuma, Katsuyoshi; Yano, Hiroshi; Tryk, Donald A; Kamino, Takeo; Uchida, Hiroyuki; Watanabe, Masahiro

    2013-07-21

    In polymer electrolyte fuel cells, it is essential to minimize Pt loading, particularly at the cathode, without serious loss of performance. From this point of view, we will report an advanced concept for the design of high performance catalysts and membrane-electrode assemblies (MEAs): first, the evaluation of Pt particle distributions on both the interior and exterior walls of various types of carbon black (CB) particles used as supports with respect to the "effective surface (ES)"; second, control of both size and location of Pt particles by means of a new preparation method (nanocapsule method); and finally, a new evaluation method for the properties of MEAs based on the Pt utilization (UPt), mass activity (MA), and effectiveness of Pt (EfPt), based on the ES concept. The amounts of Pt catalyst particles located in the CB nanopores were directly evaluated using the transmission electron microscopy, scanning electron microscopy and corresponding three-dimensional images. By use of the nanocapsule method and optimization of the ionomer, increased MA and EfPt values for the MEA were achieved. The improvement in the cathode performance can be attributed to the sharp particle-size distribution for Pt and the highly uniform dispersion on the exterior surface of graphitized carbon black (GCB) supports.

  7. Intermediate temperature single-chamber methane fed SOFC based on Gd doped ceria electrolyte and La 0.5Sr 0.5CoO 3- δ as cathode

    Science.gov (United States)

    Morales, M.; Piñol, S.; Segarra, M.

    Single-chamber fuel cells with electrodes supported on an electrolyte of gadolinium doped ceria Ce 1- xGd xO 2- y with x = 0.2 (CGO) 200 μm thickness has been successfully prepared and characterized. The cells were fed directly with a mixture of methane and air. Doped ceria electrolyte supports were prepared from powders obtained by the acetyl-acetonate sol-gel related method. Inks prepared from mixtures of precursor powders of NiO and CGO with different particle sizes and compositions were prepared, analysed and used to obtain optimal porous anodes thick films. Cathodes based on La 0.5Sr 0.5CoO 3 perovskites (LSCO) were also prepared and deposited on the other side of the electrolyte by inks prepared with a mixture of powders of LSCO, CGO and AgO obtained also by sol-gel related techniques. Both electrodes were deposited by dip coating at different thicknesses (20-30 μm) using a commercial resin where the electrode powders were dispersed. Finally, electrical properties were determined in a single-chamber reactor where methane, as fuel, was mixed with synthetic air below the direct combustion limit. Stable density currents were obtained in these experimental conditions. Temperature, composition and flux rate values of the carrier gas were determinants for the optimization of the electrical properties of the fuel cells.

  8. Highly durable anode supported solid oxide fuel cell with an infiltrated cathode

    DEFF Research Database (Denmark)

    Samson, Alfred Junio; Hjalmarsson, Per; Søgaard, Martin

    2012-01-01

    An anode supported solid oxide fuel cell with an La0.6Sr0.4Co1.05O3_δ (LSC) infiltrated-Ce0.9Gd0.1O1.95 (CGO) cathode that shows a stable performance has been developed. The cathode was prepared by screen printing a porous CGO backbone on top of a laminated and co-fired anode supported half cell...... in the resistance from the recorded impedance was observed during long term testing. The power density reached 0.79Wcm-2 at a cell voltage of 0.6 V at 750 deg. C. Post test analysis of the LSC infiltrated-CGO cathode by scanning electron microscopy revealed no significant micro-structural difference...

  9. Highly active carbon supported Pd cathode catalysts for direct formic acid fuel cells

    Science.gov (United States)

    Mikolajczuk-Zychora, A.; Borodzinski, A.; Kedzierzawski, P.; Mierzwa, B.; Mazurkiewicz-Pawlicka, M.; Stobinski, L.; Ciecierska, E.; Zimoch, A.; Opałło, M.

    2016-12-01

    One of the drawbacks of low-temperature fuel cells is high price of platinum-based catalysts used for the electroreduction of oxygen at the cathode of the fuel cell. The aim of this work is to develop the palladium catalyst that will replace commonly used platinum cathode catalysts. A series of palladium catalysts for oxygen reduction reaction (ORR) were prepared and tested on the cathode of Direct Formic Acid Fuel Cell (DFAFC). Palladium nanoparticles were deposited on the carbon black (Vulcan) and on multiwall carbon nanotubes (MWCNTs) surface by reduction of palladium(II) acetate dissolved in ethanol. Hydrazine was used as a reducing agent. The effect of functionalization of the carbon supports on the catalysts physicochemical properties and the ORR catalytic activity on the cathode of DFAFC was studied. The supports were functionalized by treatment in nitric acid for 4 h at 80 °C. The structure of the prepared catalysts has been characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscope (TEM) and cyclic voltammetry (CV). Hydrophilicity of the catalytic layers was determined by measuring contact angles of water droplets. The performance of the prepared catalysts has been compared with that of the commercial 20 wt.% Pt/C (Premetek) catalyst. The maximum power density obtained for the best palladium catalyst, deposited on the surface of functionalized carbon black, is the same as that for the commercial Pt/C (Premetek). Palladium is cheaper than platinum, therefore the developed cathode catalyst is promising for future applications.

  10. Carbon supported ruthenium chalcogenide as cathode catalyst in a microfluidic formic acid fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Gago, A.S.; Alonso-Vante, N. [Laboratory of Electrocatalysis, UMR-CNRS 6503, Universite de Poitiers, 40 Avenue du Recteur Pineau, F-86022 Potiers Cedex (France); Morales-Acosta, D.; Arriaga, L.G. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, S.C. Parque Tecnologico Queretaro Sanfandila, P.O. Box 064, Pedro Escobedo, 76703, Queretaro (Mexico)

    2011-02-01

    This work reports the electrochemical measurements of 20 wt.% Ru{sub x}Se{sub y}/C for oxygen reduction reaction (ORR) in presence of different concentration of HCOOH and its use as cathode catalyst in a microfluidic formic acid fuel cell ({mu}FAFC). The results were compared to those obtained with commercial Pt/C. Half-cell electrochemical measurements showed that the chalcogenide catalyst has a high tolerance and selectivity towards ORR in electrolytes containing up to 0.1 M HCOOH. The depolarization effect was higher on Pt/C than on Ru{sub x}Se{sub y}/C by a factor of ca. 23. Both catalysts were evaluated as cathode of a {mu}FAFC operating with different concentrations of HCOOH. When 0.5 M HCOOH was used, maximum current densities of 11.44 mA cm{sup -2} and 4.44 mA cm{sup -2} were obtained when the cathode was Ru{sub x}Se{sub y}/C and Pt/C, respectively. At 0.5 M HCOOH, the peak power density of the {mu}FAFC was similar for both catalysts, ca. 1.9 mW cm{sup -2}. At 5 M HCOOH the power density of the {mu}FAFC using Ru{sub x}Se{sub y}, was 9.3 times higher than the obtained with Pt/C. (author)

  11. Preparation and Characterization of Anode-Supported YSZ Thin Film Electrolyte by Co-Tape Casting and Co-Sintering Process

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Q L; Fu, C J; Chan, S H [School of Mechanical and Aerospace Engineering, Nanyang Technological University (Singapore); Pasciak, G, E-mail: qlliu@ntu.edu.s [Electrotechnical Institute Division of Electrotechnology and Materials Science (Poland)

    2011-06-15

    In this study, a co-tape casting and co-sintering process has been developed to prepare yttria-stabilized zirconia (YSZ) electrolyte films supported on Ni-YSZ anode substrates in order to substantially reduce the fabrication cost of solid oxide fuel cells (SOFC). Through proper control of the process, the anode/electrolyte bilayer structures with a size of 7.8cm x 7.8cm were achieved with good flatness. Scanning electron microscopy (SEM) observation indicated that the YSZ electrolyte film was about 16 {mu}m in thickness, highly dense, crack free and well-bonded to the anode support. The electrochemical properties of the prepared anode-supported electrolyte film was evaluated in a button cell mode incorporating a (LaSr)MnO{sub 3}-YSZ composite cathode. With humidified hydrogen as the fuel and stationary air as the oxidant, the cell demonstrated an open-circuit voltage of 1.081 V and a maximum power density of 1.01 W/cm{sup 2} at 800 deg. C. The obtained results represent the important progress in the development of anode-supported intermediate temperature SOFC with reduced fabrication cost.

  12. Jeffamine® based polymers as highly conductive polymer electrolytes and cathode binder materials for battery application

    Science.gov (United States)

    Aldalur, Itziar; Zhang, Heng; Piszcz, Michał; Oteo, Uxue; Rodriguez-Martinez, Lide M.; Shanmukaraj, Devaraj; Rojo, Teofilo; Armand, Michel

    2017-04-01

    We report a simple synthesis route towards a new type of comb polymer material based on polyether amines oligomer side chains (i.e., Jeffamine® compounds) and a poly(ethylene-alt-maleic anhydride) backbone. Reaction proceeds by imide ring formation through the NH2 group allowing for attachment of side chains. By taking advantage of the high configurational freedoms and flexibility of propylene oxide/ethylene oxide units (PO/EO) in Jeffamine® compounds, novel polymer matrices were obtained with good elastomeric properties. Fully amorphous solid polymer electrolytes (SPEs) based on lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and Jeffamine®-based polymer matrices show low glass transition temperatures around -40 °C, high ionic conductivities and good electrochemical stabilities. The ionic conductivities of Jeffamine-based SPEs (5.3 × 10-4 S cm-1 at 70 °C and 4.5 × 10-5 S cm-1 at room temperature) are higher than those of the conventional SPEs comprising of LiTFSI and linear poly(ethylene oxide) (PEO), due to the amorphous nature and the high concentration of mobile end-groups of the Jeffamine-based polymer matrices rather than the semi-crystalline PEO The feasibility of Jeffamine-based compounds in lithium metal batteries is further demonstrated by the implementation of Jeffamine®-based polymer as a binder for cathode materials, and the stable cycling of Li|SPE|LiFePO4 and Li|SPE|S cells using Jeffamine-based SPEs.

  13. Advanced catalyst supports for PEM fuel cell cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Du, Lei; Shao, Yuyan; Sun, Junming; Yin, Geping; Liu, Jun; Wang, Yong

    2016-11-01

    Electrocatalyst support materials are key components for polymer exchange membrane (PEM) fuel cells, which play a critical role in determining electrocatalyst durability and activity, mass transfer and water management. The commonly-used supports, e.g. porous carbon black, cannot meet all the requirements under the harsh operation condition of PEM fuel cells. Great efforts have been made in the last few years in developing alternative support materials. In this paper, we selectively review recent progress on three types of important support materials: carbon, non-carbon and hybrid carbon-oxides nanocomposites. A perspective on future R&D of electrocatalyst support materials is also provided.

  14. Pt supported on carbon nanofibers as electrocatalyst for low temperature polymer electrolyte membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Alcaide, Francisco; Alvarez, Garbine; Miguel, Oscar [Dpto. de Energia, CIDETEC, Paseo Miramon, 196, 20009 Donostia/San Sebastian (Spain); Lazaro, Maria Jesus; Moliner, Rafael [Instituto de Carboquimica, CSIC, Miguel Luesma Castan 4, 50018 Zaragoza (Spain); Lopez-Cudero, Ana; Solla-Gullon, Jose; Herrero, Enrique; Aldaz, Antonio [Instituto de Electroquimica, Universidad de Alicante, Apdo. 99, E-03080 Alicante (Spain)

    2009-05-15

    Carbon nanofibers synthesized via the thermo catalytic decomposition of methane were investigated for the first time as an electrocatalyst support in PEMFC cathodes. Their textural and physical properties make them a highly efficient catalyst support for cathodic oxygen reduction in low temperature PEMFC. Tests performed in MEAs showed that Pt supported on carbon nanofibers exhibited an enhancement of ca. 94% in power density at 0.600 V, in comparison with a commercial catalyst supported on conventional carbon black, Pt/Vulcan XC-72R. (author)

  15. Effects of 12-crown-4 ether on the electrochemical performance of CoO2 and TiS2 cathodes in Li polymer electrolyte cells

    Science.gov (United States)

    Nagasubramanian, G.; Attia, Alan I.; Halpert, G.

    1992-01-01

    The effect of adding 12-crown-4 ether (12Cr4) to the polyethylene oxide (PEO) electrolyte on the electrochemical properties of cells with Li(x)CoO2 or TiS2 as the cathode was investigated. The polymer electrolyte films were: (1) PEO, LiBF4; (2) PEO, LiBF4 with 12Cr4; (3) Li(x)CoO2, PEO, and LiBF4; and (4) Li(x)CoO2, PEO, LiBF4, and 12Cr4. It was found that, although 12Cr4 improved the cell performance over cells without 12Cr4 in the shallow c/d cycles (cyclic voltammetric behavior), it did not seem to prolong the active life of the cell. The cells with CoO2 as the cathode failed after a few c/d cycles, while similar cells with TiS2 did not fail even after 12 c/d cycles. The probable cause of failure in the case of CoO2 is ascribed to the instability of the CoO2 cathode.

  16. Break down of losses in thin electrolyte SOFCs

    DEFF Research Database (Denmark)

    Barfod, Rasmus; Hagen, Anke; Ramousse, S.

    2006-01-01

    The contributions of the individual components of the cell (anode, cathode, and electrolyte) to the cell resistance were determined experimentally, directly from impedance spectra obtained from a full cell. It was an anode supported thin electrolyte cell, consisting of a YSZ electrolyte, a Ni....../YSZ cermet anode, and a LSM composite cathode. Additional, qualitative information was obtained using symmetric cells with LSM composite electrodes. The investigations were carried out in the temperature interval from 700 to 850 degrees C. The electrolyte and anode activation energies obtained were 0.9 and 1...

  17. Influence of electrolyte additives on the cathode electrolyte interphase (CEI) formation on LiNi1/3Mn1/3Co1/3O2 in half cells with Li metal counter electrode

    Science.gov (United States)

    Qian, Yunxian; Niehoff, Philip; Börner, Markus; Grützke, Martin; Mönnighoff, Xaver; Behrends, Pascal; Nowak, Sascha; Winter, Martin; Schappacher, Falko M.

    2016-10-01

    Traditional solid electrolyte interphase (SEI) forming additives of vinylene carbonate (VC), fluoroethylene carbonate (FEC) and ethylene sulfite (ES) are studied with respect to their impact on the formation and growth of the cathode electrolyte interphase (CEI) layer. T-half cells are assembled and undergo three different electrochemical investigation plans: after formation (0.1C, 5 cycles) and long term cycling (0.1C, 5 constant current cycles + 1C, 100/150 constant current/voltage cycles), scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and gas chromatography-mass spectrometry (GC-MS) are combined to investigate morphology, CEI composition, CEI thickness and aging products for cells with different electrolyte systems. The obtained results reveal a significant influence of these additives on the CEI composition and CEI growth. With the help of SEM, it is found that large areas of electrolyte decomposition products are formed at the aged electrode surfaces (=after cycling), with the exception when 2 vol% of FEC is added into the reference electrolyte. From XPS measurements, CEI thicknesses are calculated. The reference electrolyte with 2 vol% of FEC shows the thinnest layer after long time aging (0.8 ± 0.2 nm). For the addition of 2 vol% of VC, an incremental growth of the CEI thickness occurs from the 100th to 150th cycle (from 1.0 ± 0.1 nm to 2.9 ± 0.4 nm). By correlating the CEI thickness values with the electrochemical performance, it can be observed that for lithium metal based half cells, the existence of a thinner CEI layer corresponds to a better cycling behavior, with 2 vol% of FEC showing the highest discharge capacity of 114.4 ± 0.2 mAh/g after 150 cycles at 1C. GC-MS shows that both VC and FEC help to prevent fast electrolyte aging.

  18. Chloride supporting electrolytes for all-vanadium redox flow batteries.

    Science.gov (United States)

    Kim, Soowhan; Vijayakumar, M; Wang, Wei; Zhang, Jianlu; Chen, Baowei; Nie, Zimin; Chen, Feng; Hu, Jianzhi; Li, Liyu; Yang, Zhenguo

    2011-10-28

    This paper examines vanadium chloride solutions as electrolytes for an all-vanadium redox flow battery. The chloride solutions were capable of dissolving more than 2.3 M vanadium at varied valence states and remained stable at 0-50 °C. The improved stability appeared due to the formation of a vanadium dinuclear [V(2)O(3)·4H(2)O](4+) or a dinuclear-chloro complex [V(2)O(3)Cl·3H(2)O](3+) in the solutions over a wide temperature range. The all-vanadium redox flow batteries with the chloride electrolytes demonstrated excellent reversibility and fairly high efficiencies. Only negligible, if any, gas evolution was observed. The improved energy capacity and good performance, along with the ease in heat management, would lead to substantial reduction in capital cost and life-cycle cost, making the vanadium chloride redox flow battery a promising candidate for stationary applications.

  19. Performance study of magnesium-sulfur battery using a graphene based sulfur composite cathode electrode and a non-nucleophilic Mg electrolyte

    Science.gov (United States)

    Vinayan, B. P.; Zhao-Karger, Zhirong; Diemant, Thomas; Chakravadhanula, Venkata Sai Kiran; Schwarzburger, Nele I.; Cambaz, Musa Ali; Behm, R. Jürgen; Kübel, Christian; Fichtner, Maximilian

    2016-02-01

    Here we report for the first time the development of a Mg rechargeable battery using a graphene-sulfur nanocomposite as the cathode, a Mg-carbon composite as the anode and a non-nucleophilic Mg based complex in tetraglyme solvent as the electrolyte. The graphene-sulfur nanocomposites are prepared through a new pathway by the combination of thermal and chemical precipitation methods. The Mg/S cell delivers a higher reversible capacity (448 mA h g-1), a longer cyclability (236 mA h g-1 at the end of the 50th cycle) and a better rate capability than previously described cells. The dissolution of Mg polysulfides to the anode side was studied by X-ray photoelectron spectroscopy. The use of a graphene-sulfur composite cathode electrode, with the properties of a high surface area, a porous morphology, a very good electronic conductivity and the presence of oxygen functional groups, along with a non-nucleophilic Mg electrolyte gives an improved battery performance.Here we report for the first time the development of a Mg rechargeable battery using a graphene-sulfur nanocomposite as the cathode, a Mg-carbon composite as the anode and a non-nucleophilic Mg based complex in tetraglyme solvent as the electrolyte. The graphene-sulfur nanocomposites are prepared through a new pathway by the combination of thermal and chemical precipitation methods. The Mg/S cell delivers a higher reversible capacity (448 mA h g-1), a longer cyclability (236 mA h g-1 at the end of the 50th cycle) and a better rate capability than previously described cells. The dissolution of Mg polysulfides to the anode side was studied by X-ray photoelectron spectroscopy. The use of a graphene-sulfur composite cathode electrode, with the properties of a high surface area, a porous morphology, a very good electronic conductivity and the presence of oxygen functional groups, along with a non-nucleophilic Mg electrolyte gives an improved battery performance. Electronic supplementary information (ESI) available

  20. Tris(2,2,2-trifluoroethyl) phosphite as an electrolyte additive for high-voltage lithium-ion batteries using lithium-rich layered oxide cathode

    Science.gov (United States)

    Pires, Julie; Castets, Aurore; Timperman, Laure; Santos-Peña, Jesùs; Dumont, Erwan; Levasseur, Stéphane; Tessier, Cécile; Dedryvère, Rémi; Anouti, Mérièm

    2015-11-01

    In this paper, we report positive effect of Tris(2,2,2-trifluoroethyl) phosphite (TTFP) as additive during initial activation and cycling of Li-rich-NMC xLi2MnO3-(1 - x)LiMO2 (x >> 1; M = Ni, Co, Mn) cathode in EC/DMC + 1 M LiPF6 electrolyte. Firstly conductivity and viscosity of electrolyte with x wt.% TTFP; 0 wt.% NMC full cell is maintained after 50 cycles at C rate. Finally, XPS analysis of Li-rich -NMC electrodes show presence of TTFP on the surface during cycling and confirm the presence of Mn3+ at the end of discharge. The convergence of all characterizations indicates that TTFP should act as a catalyst to several surface reactions which are beneficial to long cycling cell performances.

  1. Metal-supported solid oxide fuel cells with impregnated SrFe0.75Mo0.25O3 cathodes

    Science.gov (United States)

    Zhou, Yucun; Meng, Xie; Ye, Xiaofeng; Li, Junliang; Wang, Shaorong; Zhan, Zhongliang

    2014-02-01

    This paper reports on the fabrication in reducing atmospheres of SrFe0.75Mo0.25O3 (SFMO)-8 mol%Y2O3-stabilized ZrO2 (YSZ) composites by impregnating Sr2+-, Fe3+- and Mo7O246--containing solutions into the porous YSZ backbones, which would find important applications as cathodes for co-fired metal-supported solid oxide fuel cells. X-ray diffraction examination shows that as-synthesized infiltrates consist of perovskite SFMO oxides and metallic Fe. In situ oxidation during the fuel cell operation eliminates metallic Fe, and SFMO oxides become the predominant component with some minor SrMoO4 impurities. Impedance measurements on symmetric cathode fuel cells show that such impregnated SFMO-YSZ composites exhibit low polarization resistances in air, e.g., 0.06 Ω cm2 at 800 °C. Metal-supported solid oxide fuel cells, consisting of porous 430L stainless steel substrates, Ni-YSZ active anodes, YSZ electrolytes and impregnated SFMO-YSZ composite cathodes, are fabricated using tape casting, tape lamination, co-sintering and solution impregnation techniques, and show maximum power densities of 438 mW cm-2 at 800 °C and 221 mW cm-2 at 700 °C.

  2. Detection of some industrially relevant elements in water by electrolyte cathode atmospheric glow discharge optical emission spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Bencs, László, E-mail: bencs.laszlo@wigner.mta.hu [Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, PO Box 49, Budapest H-1525 (Hungary); Laczai, Nikoletta; Mezei, Pál [Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, PO Box 49, Budapest H-1525 (Hungary); Cserfalvi, Tamás [T. Meisel Laboratory, Aqua-Concorde R& D LLC, Budapest, Bosnyák utca 11, H-1145 (Hungary)

    2015-05-01

    An electrolyte cathode atmospheric glow discharge optical emission spectrometry (ELCAD-OES) method was developed for the detection of the industrially relevant In, Rh and Te in water samples. Acid/additive type, sample pH and flow rate were optimized. The UV–Vis spectrum was scanned for analytical lines, free from spectral overlap interferences, and sensitive enough for quantifying the analytes at mg L{sup −1} or lower levels. In several cases, the background spectrum of the ELCAD hindered the use of conventional, resonant analytical lines in the UV due to overlaps with bands of molecular species (e.g., OH, NO, N{sub 2}). Te and Rh showed lower emission intensities than In (determined at In I 451.1 nm), even using the most sensitive, interference-free transitions (i.e., Te I 214.3 nm, Te I 238.6 nm and Rh I 437.5 nm). The emission intensities were highly sample pH dependent, i.e., analytical signals could only be detected at pH levels lower than 2. Conversely, the use of acidity lower than pH 1 caused lower plasma volume, due to its contraction into the sample introduction capillary, and discharge instability in terms of its frequent self-extinction. The detection limits for In, Rh and Te were 0.01, 0.5 and 2.4 mg L{sup −1}, respectively. Calibration curves were linear up to 100–150 mg L{sup −1}. The precision for In, Rh and Te in aqueous standards, expressed as relative standard deviation (RSD), was not higher than 4.6%, 6.4% and 7.4%, respectively. Samples with high salt content (e.g., well water) caused positive matrix effects (i.e., 2.0- to 3.6-fold signal enhancements), but also ~ 1.5 times higher RSDs. - Highlights: • An ELCAD-OES method is developed for the monitoring of In, Rh and Te in waters. • The UV–Vis emission spectrum was studied for interference-free spectral lines. • Effects of sample pH, acid-type on signal intensities and GD voltage were studied. • Calibration and analytical figures for low- to high-salinity waters were

  3. The Dilemma of Supporting Electrolytes for Electroorganic Synthesis: A Case Study on Kolbe Electrolysis.

    Science.gov (United States)

    Stang, Carolin; Harnisch, Falk

    2016-01-08

    Remarkably, coulombic efficiency (CE, about 50 % at 1 Farad equivalent), and product composition resulting from aqueous Kolbe electrolysis are independent of reactor temperature and initial pH value. Although numerous studies on Kolbe electrolysis are available, the interrelations of different reaction parameters (e.g., acid concentration, pH, and especially electrolytic conductivity) are not addressed. A systematic analysis based on cyclic voltammetry reveals that solely the electrolytic conductivity impacts the current-voltage behavior. When using supporting electrolytes, not only their concentration, but also the type is decisive. We show that higher concentrations of KNO3 result in reduced CE and thus in significant increase in electric energy demand per converted molecule, whereas Na2 SO4 allows improved space-time yields. Pros and cons of adding supporting electrolytes are discussed in a final cost assessment.

  4. High Performance Cathodes for Li-Air Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Xing, Yangchuan

    2013-08-22

    The overall objective of this project was to develop and fabricate a multifunctional cathode with high activities in acidic electrolytes for the oxygen reduction and evolution reactions for Li-air batteries. It should enable the development of Li-air batteries that operate on hybrid electrolytes, with acidic catholytes in particular. The use of hybrid electrolytes eliminates the problems of lithium reaction with water and of lithium oxide deposition in the cathode with sole organic electrolytes. The use of acid electrolytes can eliminate carbonate formation inside the cathode, making air breathing Li-air batteries viable. The tasks of the project were focused on developing hierarchical cathode structures and bifunctional catalysts. Development and testing of a prototype hybrid Li-air battery were also conducted. We succeeded in developing a hierarchical cathode structure and an effective bifunctional catalyst. We accomplished integrating the cathode with existing anode technologies and made a pouch prototype Li-air battery using sulfuric acid as catholyte. The battery cathodes contain a nanoscale multilayer structure made with carbon nanotubes and nanofibers. The structure was demonstrated to improve battery performance substantially. The bifunctional catalyst developed contains a conductive oxide support with ultra-low loading of platinum and iridium oxides. The work performed in this project has been documented in seven peer reviewed journal publications, five conference presentations, and filing of two U.S. patents. Technical details have been documented in the quarterly reports to DOE during the course of the project.

  5. On the crucial influence of some supporting electrolytes during electrocoagulation in the presence of aluminum electrodes

    OpenAIRE

    Trompette, Jean-Luc; Vergnes, Hugues

    2009-01-01

    The influence of some supporting electrolytes on aluminum electrode oxidation and pH variation during electrocoagulation of an unskimmed milk sample and a cutting oil emulsion has been investigated. Among the electrolytes studied, sulfate anions were found to be quite harmful both for electrical consumption and electrocoagulation efficiency. At the opposite, chloride and ammonium ionswere particularly benefic respectively for aluminum corrosion and pH regulation, whereas sodium cations were o...

  6. Development of open-air type electrolyte-as-cathode glow discharge-atomic emission spectrometry for determination of trace metals in water

    Science.gov (United States)

    Kim, Hyo J.; Lee, Jeong H.; Kim, Myung Y.; Cserfalvi, T.; Mezei, P.

    2000-07-01

    The open-air type electrolyte cathode atomic glow discharge (ELCAD) has been developed and studied for fundamental and analytical applications for determination of trace heavy metals in water. The normal closed-type discharge cell shows some problems such as unstable plasma due to changes in the pressure inside the cell during the discharge, and water vapor condensing onto the window. Applying approximately 1500 V to the several-millimeter gap between the electrolyte solution cathode and a Pt rod anode in atmospheric air pressure produced a stable plasma and significantly improved sensitivity. The emission spectrum of de-ionized water containing 100 mg/l Cu was measured and some emission lines were found from Cu I (324.7 nm, 327.4 nm and 510.5 nm) and Cu II (224.7 nm and 229.4 nm). The LODs of Cr, Cu, Fe, Mn, Ni, Pb, and Zn are in the ranges from 0.01 mg/l to 0.6 mg/l. The LODs of Cu, Mn, Pb and Zn improve by approximately one order of magnitude compared to the previous closed-type ELCAD.

  7. Influence of characteristics of stabilized zirconia electrolyte on performance of cermet supported tubular SOFCs

    Institute of Scientific and Technical Information of China (English)

    LI Changjiu; LI Chengxin; XING Yazhe; XIE Yingxin; LONG Huiguo

    2006-01-01

    Ni-Al2O3 cermet supported tubular SOFC was fabricated by thermal spraying. Flame-sprayed Al2O3-Ni cermet coating plays dual roles of a support tube and an anode current collector. 4.5mol.% yttria-stabilized zirconia (YSZ) and 10mol.% scandia-stabilized zirconia (ScSZ) coatings were deposited by atmospheric plasma spraying (APS) as the electrolyte in present study. The electrical conductivity of electrolyte was measured using DC method. The post treatment was employed using nitrate solution infiltration to densify APS electrolyte layer for improvement of gas permeability. The electrical conductivity of electrolyte and the performance of single cell were investigated to optimize SOFC performance. The electrical conductivity of the as-sprayed YSZ and ScSZ coating is about 0.03 and 0.07 S·cm-1 at 1000 ℃, respectively. The ohmic polarization significantly influences the performance of SOFC. The maximum output power density at 1000 ℃ increases from 0.47 to 0.76 W·cm-2 as the YSZ electrolyte thickness reduces from 100 μm to 40 μm. Using APS ScSZ coating of about 40 μm as the electrolyte, the test cell presents a maximum power output density of over 0.89 W·m-2 at 1000 ℃.

  8. Studies on film formation on cathodes using pyrazole derivatives as electrolyte additives in the Li-ion battery

    Energy Technology Data Exchange (ETDEWEB)

    Kam, Daewoong; Kim, Ketack; Kim, Hyun-Soo [Battery Research Group, Korea Electrotechnology Research Institute, Changwon 641-600 (Korea); Liu, Hua Kun [Energy Materials Research Program, Institute for Superconducting and Electronic Materials, ARC Centre for Electromaterials Science, University of Wollongong, NSW 2519 (Australia)

    2009-08-15

    Pyrazole derivatives are flame retardants and provide thermal protection on cathodes, as they help to form a thick protective film. A thicker film provides more protection and delays the thermal decomposition of the cathode. Among the tested pyrazoles, bis(trifluoromethyl)pyrazole (BFTMP) serves as the best flame retardant additive. Additionally, a cell with BFTMP shows better capacity retention than a cell with no additive in full-cell cycle life tests. (author)

  9. Solid polymer electrolyte composite membrane comprising a porous support and a solid polymer electrolyte including a dispersed reduced noble metal or noble metal oxide

    Science.gov (United States)

    Liu, Han; Mittelsteadt, Cortney K; Norman, Timothy J; Griffith, Arthur E; LaConti, Anthony B

    2015-02-24

    A solid polymer electrolyte composite membrane and method of manufacturing the same. According to one embodiment, the composite membrane comprises a thin, rigid, dimensionally-stable, non-electrically-conducting support, the support having a plurality of cylindrical, straight-through pores extending perpendicularly between opposing top and bottom surfaces of the support. The pores are unevenly distributed, with some or no pores located along the periphery and more pores located centrally. The pores are completely filled with a solid polymer electrolyte, the solid polymer electrolyte including a dispersed reduced noble metal or noble metal oxide. The solid polymer electrolyte may also be deposited over the top and/or bottom surfaces of the support.

  10. Scalable air cathode microbial fuel cells using glass fiber separators, plastic mesh supporters, and graphite fiber brush anodes

    KAUST Repository

    Zhang, Xiaoyuan

    2011-01-01

    The combined use of brush anodes and glass fiber (GF1) separators, and plastic mesh supporters were used here for the first time to create a scalable microbial fuel cell architecture. Separators prevented short circuiting of closely-spaced electrodes, and cathode supporters were used to avoid water gaps between the separator and cathode that can reduce power production. The maximum power density with a separator and supporter and a single cathode was 75±1W/m3. Removing the separator decreased power by 8%. Adding a second cathode increased power to 154±1W/m3. Current was increased by connecting two MFCs connected in parallel. These results show that brush anodes, combined with a glass fiber separator and a plastic mesh supporter, produce a useful MFC architecture that is inherently scalable due to good insulation between the electrodes and a compact architecture. © 2010 Elsevier Ltd.

  11. Effects of NiO on the conductivity of Ce0.85Sm0.15O1.925 and on electrochemical properties of the cathode/electrolyte interface

    Science.gov (United States)

    Wang, Haopeng; Liu, Xiaomei; Bi, Hailin; Yu, Shenglong; Han, Fei; Sun, Jialing; Zhu, Lili; Yu, Huamin; Pei, Li

    2016-07-01

    Ce0.85Sm0.15O1.925 (SDC) and Ce0.85Sm0.15O1.925-0.5 at.% NiO (SDCN) are investigated as electrolytes for solid oxide fuel cells (SOFCs). Impedance spectroscopy measurements reveal that the grain boundary resistance can be significantly reduced by adding 0.5 at.% NiO to SDC. Symmetric cells of the BaCo0.7Fe0.2Nb0.1O3-δ (BCFN) electrode on SDC and SDCN electrolytes are fabricated and the electrochemical properties of the electrode/electrolyte interface are investigated. The polarization resistance of the BCFN electrode on the SDCN electrolyte is much lower than that of the BCFN electrode on the SDC electrolyte, mainly because of the increase in the electrolyte conductivity and the decrease in the Si content at the electrode/electrolyte interface. NiO is able to restrict the diffusion of the siliceous impurity from the electrolyte to the electrode/electrolyte interface. Single cells based on SDC and SDCN electrolytes are fabricated using Ni0.9Cu0.1Ox-SDC as the anode and BCFN as the cathode. At 800 °C, the maximum power density of the SDCN-based cell is 0.745 W cm-2, which is much higher than that of the SDC-based cell.

  12. In-situ electrochemically active surface area evaluation of an open-cathode polymer electrolyte membrane fuel cell stack

    Science.gov (United States)

    Torija, Sergio; Prieto-Sanchez, Laura; Ashton, Sean J.

    2016-09-01

    The ability to evaluate the electrochemically active surface area (ECSA) of fuel cell electrodes is crucial toward characterising designs and component suites in-situ, particularly when evaluating component durability in endurance testing, since it is a measure of the electrode area available to take part in the fuel cell reactions. Conventional methods to obtain the ECSA using cyclic voltammetry, however, rely on potentiostats that cannot be easily scaled to simultaneously evaluate all cells in a fuel cell stack of practical size, which is desirable in fuel cell development. In-situ diagnostics of an open-cathode fuel cell stack are furthermore challenging because the cells do not each possess an enclosed cathode compartment; instead, the cathodes are rather open to the environment. Here we report on a diagnostic setup that allows the electrochemically active surface area of each cell anode or cathode in an open-cathode fuel cell stack to be evaluated in-situ and simultaneously, with high resolution and reproducibility, using an easily scalable chronopotentiometry methodology and a gas-tight stack enclosure.

  13. Analysis of liquid water formation in polymer electrolyte membrane (PEM) fuel cell flow fields with a dry cathode supply

    Science.gov (United States)

    Gößling, Sönke; Klages, Merle; Haußmann, Jan; Beckhaus, Peter; Messerschmidt, Matthias; Arlt, Tobias; Kardjilov, Nikolay; Manke, Ingo; Scholta, Joachim; Heinzel, Angelika

    2016-02-01

    PEM fuel cells can be operated within a wide range of different operating conditions. In this paper, the special case of operating a PEM fuel cell with a dry cathode supply and without external humidification of the cathode, is considered. A deeper understanding of the water management in the cells is essential for choosing the optimal operation strategy for a specific system. In this study a theoretical model is presented which aims to predict the location in the flow field at which liquid water forms at the cathode. It is validated with neutron images of a PEM fuel cell visualizing the locations at which liquid water forms in the fuel cell flow field channels. It is shown that the inclusion of the GDL diffusion resistance in the model is essential to describe the liquid water formation process inside the fuel cell. Good agreement of model predictions and measurement results has been achieved. While the model has been developed and validated especially for the operation with a dry cathode supply, the model is also applicable to fuel cells with a humidified cathode stream.

  14. Performance improvement of anode-supported electrolytes for planar solid oxide fuel cells via a tape-casting/lamination/co-firing technique

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hae-Gu; Moon, Hwan; Park, Sung-Chul; Lee, Jong-Jin; Yoon, Daeil; Hyun, Sang-Hoon [School of Advanced Materials Science and Engineering, Yonsei University, Seoul 120-749 (Korea); Kim, Do-Heyoung [Research Institute of Industrial Science and Technology, Kyuongpook 790-600 (Korea)

    2010-05-01

    Recently, solid oxide fuel cells (SOFCs) have attracted considerable attention because of their low emissions, high-energy conversion efficiency, and flexible usage of various fuels. One of the key problems of applying flat-type SOFCs to large-scale power generation is that unit cells of large area and with a high degree of flatness cannot be manufactured satisfactorily. In this study, the effects of tape-casting, laminating, and co-firing conditions on the flatness of anode-supported electrolyte unit cells have been investigated to improve the cell performance of unit cells. The cells are composed of a Ni-yttria-stabilized zirconia (YSZ) anode, a Ni-YSZ anode functional layer (AFL), a YSZ electrolyte, and a lanthanum strontium manganate (LSM)-YSZ cathode. The flatness of the anode-supported electrolyte is optimized by controlling the firing schedule, the lamination method, and the applied load during firing. A 5 cm x 5 cm (active area 4 cm x 4 cm) unit cell having a reasonable flatness of 55 {mu}m/5 cm shows a higher power output of 11.4 W as compared with 7.7 W a unit cell with a flatness of 200 {mu}m/5 cm, when operating at 800 C with humidified hydrogen fuel. (author)

  15. A new sealed lithium-peroxide battery with a co-doped Li2O cathode in a superconcentrated lithium bis(fluorosulfonyl)amide electrolyte.

    Science.gov (United States)

    Okuoka, Shin-ichi; Ogasawara, Yoshiyuki; Suga, Yosuke; Hibino, Mitsuhiro; Kudo, Tetsuichi; Ono, Hironobu; Yonehara, Koji; Sumida, Yasutaka; Yamada, Yuki; Yamada, Atsuo; Oshima, Masaharu; Tochigi, Eita; Shibata, Naoya; Ikuhara, Yuichi; Mizuno, Noritaka

    2014-07-14

    We propose a new sealed battery operating on a redox reaction between an oxide (O(2-)) and a peroxide (O2(2-)) with its theoretical specific energy of 2570 Wh kg(-1) (897 mAh g(-1), 2.87 V) and demonstrate that a Co-doped Li2O cathode exhibits a reversible capacity over 190 mAh g(-1), a high rate capability, and a good cyclability with a superconcentrated lithium bis(fluorosulfonyl)amide electrolyte in acetonitrile. The reversible capacity is largely dominated by the O(2-)/O2(2-) redox reaction between oxide and peroxide with some contribution of the Co(2+)/Co(3+) redox reaction.

  16. Effect of the compactness of the lithium chloride layer formed on the carbon cathode on the electrochemical reduction of SOCl{sub 2} electrolyte in Li-SOCl{sub 2} batteries

    Energy Technology Data Exchange (ETDEWEB)

    Seung-Bok Lee; Su-Il Pyun [Korea Advanced Institute of Science and Technology, Taejon (Korea). Dept. of Materials Science and Engineering; Eung-Jo Lee [Hana Tek Co Ltd., Kyounggi (Korea). R and D Center

    2001-07-01

    Effect of the compactness of the lithium chloride layer formed on the carbon cathode on the electrochemical reduction of SOCl{sub 2} electrolyte in Li-SOCl{sub 2} primary battery was investigated using ac-impedance spectroscopy and potentiostatic current transient technique. From the facts that the straight lines of the Nyquist plots of the ac-impedance spectra and the peak-like runs of the plot of It{sup 1/2} versus log t were observed from the pure carbon cathode, it was suggested that the porous layer of lithium chloride deposited on the pure carbon cathode was relatively compact enough to strongly impede the diffusion of SOCl{sub 2} through it, and hence the rate-controlling step for overall SOCl{sub 2} reduction is changed from the 'interfacial reaction between the pure carbon cathode and electrolyte' to the 'diffusion of SOCl{sub 2} through the porous lithium chloride layer'. On the other hand, any of the straight lines of the Nyquist plots of the ac-impedance spectra and of the peak-like courses of the plot of It{sup 1/2} versus log t can not be found in the Co-phthalocyanine (Pc)-incorporated carbon cathode. Thus, it was concluded that the porous layer of lithium chloride formed on the Co-Pc-incorporated carbon cathode was relatively porous enough to considerably facilitate the diffusion of SOCl{sub 2} through it, and hence the overall reduction rate of SOCl{sub 2} is governed by the 'interfacial reaction between the Co-Pc-incorporated carbon cathode and electrolyte' throughout the whole discharge of the Li-SOCl{sub 2} batteries. (author)

  17. Self-discharge suppression of 4.9 V LiNi0.5Mn1.5O4 cathode by using tris(trimethylsilyl)borate as an electrolyte additive

    Science.gov (United States)

    Liao, Xiaolin; Huang, Qiming; Mai, Shaowei; Wang, Xianshu; Xu, Mengqing; Xing, Lidan; Liao, Youhao; Li, Weishan

    2014-12-01

    In this paper, tris(trimethylsilyl)borate (TMSB) is evaluated as an electrolyte additive for the self-discharge suppression of 4.9 V LiNi0.5Mn1.5O4 cathode for lithium ion battery. The effect of TMSB on the surface properties of LiNi0.5Mn1.5O4 is investigated via linear sweep voltammetry (LSV), cyclic voltammetry (CV), chronoamperometry (CA), charge-discharge test, electrochemical impedance spectra (EIS), scanning electron microscopy (SEM), X-ray diffraction (XRD), inductively coupled plasma atomic emission spectrometer (ICP-AES) and Fourier transform infrared spectroscopy (FTIR). It is found that the LiNi0.5Mn1.5O4 cathode charged to 4.9 V (vs. Li/Li+) suffers a serious self-discharge in 1 mol L-1 LiPF6-EC/DMC (1:2, in weight), which can be suppressed effectively by adding 1 wt.% TMSB into the electrolyte. After storage for 20 days, the voltage of the charged cathode decreases from 4.7 to 0.5 V (vs. Li/Li+) in the additive-free electrolyte, while that remains almost unchanged in the TMSB-containing electrolyte. The self-discharge suppression of the charged LiNi0.5Mn1.5O4 cathode results from the preferential oxidation of TMSB and the subsequent formation of a protective solid electrolyte interphase film, which prevents electrolyte decomposition and protects LiNi0.5Mn1.5O4 from destruction.

  18. Nano-nitride cathode catalysts of Ti, Ta, and Nb for polymer electrolyte fuel cells: Temperature-programmed desorption investigation of molecularly adsorbed oxygen at low temperature

    KAUST Repository

    Ohnishi, Ryohji

    2013-01-10

    TiN, NbN, TaN, and Ta3N5 nanoparticles synthesized using mesoporous graphitic (mpg)-C3N4 templates were investigated for the oxygen reduction reaction (ORR) as cathode catalysts for polymer electrolyte fuel cells. The temperature-programmed desorption (TPD) of molecularly adsorbed O2 at 120-170 K from these nanoparticles was examined, and the resulting amount and temperature of desorption were key factors determining the ORR activity. The size-dependent TiN nanoparticles (5-8 and 100 nm) were then examined. With decreasing particle size, the density of molecularly adsorbed O2 per unit of surface area increased, indicating that a decrease in particle size increases the number of active sites. It is hard to determine the electrochemical active surface area for nonmetal electrocatalysts (such as oxides or nitrides), because of the absence of proton adsorption/desorption peaks in the voltammograms. In this study, O2-TPD for molecularly adsorbed O2 at low temperature demonstrated that the amount and strength of adsorbed O2 were key factors determining the ORR activity. The properties of molecularly adsorbed O2 on cathode catalysts are discussed against the ORR activity. © 2012 American Chemical Society.

  19. Influence of supporting electrolyte in electricity generation and degradation of organic pollutants in photocatalytic fuel cell.

    Science.gov (United States)

    Khalik, Wan Fadhilah; Ong, Soon-An; Ho, Li-Ngee; Wong, Yee-Shian; Voon, Chun-Hong; Yusuf, Sara Yasina; Yusoff, Nik Athirah; Lee, Sin-Li

    2016-08-01

    This study investigated the effect of different supporting electrolyte (Na2SO4, MgSO4, NaCl) in degradation of Reactive Black 5 (RB5) and generation of electricity. Zinc oxide (ZnO) was immobilized onto carbon felt acted as photoanode, while Pt-coated carbon paper as photocathode was placed in a single chamber photocatalytic fuel cell, which then irradiated by UV lamp for 24 h. The degradation and mineralization of RB5 with 0.1 M NaCl rapidly decreased after 24-h irradiation time, followed by MgSO4, Na2SO4 and without electrolyte. The voltage outputs for Na2SO4, MgSO4 and NaCl were 908, 628 and 523 mV, respectively, after 24-h irradiation time; meanwhile, their short-circuit current density, J SC, was 1.3, 1.2 and 1.05 mA cm(-2), respectively. The power densities for Na2SO4, MgSO4 and NaCl were 0.335, 0.256 and 0.245 mW cm(-2), respectively. On the other hand, for without supporting electrolyte, the voltage output and short-circuit current density was 271.6 mV and 0.055 mA cm(-2), respectively. The supporting electrolyte NaCl showed greater performance in degradation of RB5 and generation of electricity due to the formation of superoxide radical anions which enhance the degradation of dye. The mineralization of RB5 with different supporting electrolyte was measured through spectrum analysis and reduction in COD concentration.

  20. Quercetin as electrolyte additive for LiNi0.5Mn1.5O4 cathode for lithium-ion secondary battery at elevated temperature

    Science.gov (United States)

    Kim, Sungkyung; Kim, Myeongho; Choi, Insoo; Kim, Jae Jeong

    2016-12-01

    In an attempt to ameliorate the poor cyclability of LiNi0.5Mn1.5O4 at elevated temperature, quercetin is applied as an additive. The irreversible oxidative behavior of quercetin is thoroughly investigated by electrochemical method. The improved cyclability of the quercetin-containing cell at high temperature implies that by forming robust and less-resistive SEI, quercetin is preferentially oxidized and passivates the LiNi0.5Mn1.5O4 electrode. EIS result coherently suggests that the quercetin-added electrolyte forms a more compact and Li-ion conducting interface. The surface sensitive XPS analysis confirms that the presence of quercetin restrains the formation of LiF, suppresses the reaction of PF5, and alleviates Mn dissolution. Meanwhile, ICP-MS analysis affirms the effectiveness of quercetin against Mn dissolution. The self-discharge experiment which exhibits the retained charged state of LiNi0.5Mn1.5O4 at high temperature, gives convincing evidence of the effect of quercetin. Intensive analyses confirm that quercetin can effectively prolong the cycle-life of LiNi0.5Mn1.5O4 at elevated temperature. We envision its potential and practical usage as an electrolyte additive for high-voltage cathode.

  1. Ion and gas chromatography mass spectrometry investigations of organophosphates in lithium ion battery electrolytes by electrochemical aging at elevated cathode potentials

    Science.gov (United States)

    Weber, Waldemar; Wagner, Ralf; Streipert, Benjamin; Kraft, Vadim; Winter, Martin; Nowak, Sascha

    2016-02-01

    The electrochemical aging of commercial non-aqueous lithium hexafluorophosphate (LiPF6)/organic carbonate solvent based lithium ion battery electrolyte has been investigated in view of the formation of ionic and non-ionic alkylated phosphates. Subject was a solvent mixture of ethylene carbonate/ethyl methyl carbonate EC:EMC (1:1, by wt.) with 1 M LiPF6 (LP50 Selectilyte™, BASF). The analysis was carried out by ion chromatography coupled with electrospray ionization mass spectrometry (ESI-MS) for ionic compounds and (headspace) gas chromatography mass spectrometry ((HS)-GC-MS) for non-ionic compounds. The electrochemical aging was performed by galvanostatic charge/discharge cycling and potentiostatic experiments with LiNi0.5Mn1.5O4 (LMNO) as cathode material at increased cut-off potentials (>4.5 V vs. Li/Li+). A strong dependence of the formation of organophosphates on the applied electrode potential was observed and investigated by quantitative analysis of the formed phosphates. In addition, new possible "fingerprint" compounds for describing the electrolyte status were investigated and compared to existing compounds.

  2. Triethylborate as an electrolyte additive for high voltage layered lithium nickel cobalt manganese oxide cathode of lithium ion battery

    Science.gov (United States)

    Wang, Zaisheng; Xing, Lidan; Li, JianHui; Xu, Mengqing; Li, Weishan

    2016-03-01

    Triethylborate (TEB) is used as an electrolyte additive to improve the electrochemical performances of LiNi1/3Co1/3Mn1/3O2 (LNCM) upon cycling at 4.5 V vs. Li/Li+. Charge/discharge tests demonstrate that the cyclic stability of LNCM at room and elevated temperature can be improved effectively by TEB. With addition of 10 wt. % TEB into STD electrolyte (1.0 M LiPF6/EC:EMC:DEC), LNCM achieves a capacity retention of 99.8% after 150 cycles and 94.7% after 120 cycles at room and elevated temperature, respectively, comparing to that of 68.9% and 68.8% of STD electrolyte. In addition, 10 wt. % TEB also improves the rate capability of LNCM at room temperature. Physical and electrochemical characterizations from XRD, SEM, TEM, XPS, ICP-MS, LSV, CA, and EIS reveal that the preferential oxidative reaction of TEB generates a thin, uniform and low interfacial resistance film on the LNCM surface. This film not only suppresses the subsequent decomposition of STD electrolyte, but also prevents the dissolution of transition metal ions from LNCM, resulting in improved cyclic stability and rate capability of LNCM.

  3. Nanostructured lanthanum manganate composite cathode

    DEFF Research Database (Denmark)

    Wang, Wei Guo; Liu, Yi-Lin; Barfod, Rasmus

    2005-01-01

    Anode-supported cells were fabricated with optimized cathodes showing high power density of 1.2 W/cm(2) at 800 C under a cell voltage of 0.7 V and an active area of 4 x 4 cm. A microstructure study was performed on such cell using a field-emission gun scanning electron microscope, which revealed...... that the (La1-xSrx)(y)MnO3 +/-delta (LSM) composite cathodes consist of a network of homogenously distributed LSM, yttria-stabilized zirconia (YSZ), and pores. The individual grain size of LSM or YSZ is approximately 100 nm. The degree of contact between cathode and electrolyte is 39% on average. (c) 2005...

  4. Synthesis and characterization of 3D Ni nanoparticle/carbon nanotube cathodes for hydrogen evolution in alkaline electrolyte

    Science.gov (United States)

    McArthur, M. A.; Jorge, L.; Coulombe, S.; Omanovic, S.

    2014-11-01

    Renewable alternative energy sources are required to decrease or eliminate the use of environmentally unfriendly fossil fuels. Hydrogen produced by electrolysis has been identified as one such renewable energy carrier. In the current work, Ni nanoparticle (NP)-decorated multiwall carbon nanotube (MWCNT) electrocatalyst cathodes are prepared by a simple two-step procedure. MWCNTs are grown on stainless steel meshes by thermal-chemical vapour deposition (t-CVD) and then decorated with Ni NPs by pulsed laser ablation (PLA). The morphological and electrochemical properties of the produced Ni NP/MWCNT cathodes were characterized through electron microscopy and linear Tafel polarization (LTP)/electrochemical impedance spectroscopy (EIS), respectively. SEM and TEM imaging revealed that the Ni NPs deposited by PLA are on the order of 4 nm in diameter with a narrow size distribution. The LTP measurements showed that the electrocatalytic activity of the Ni NP/MWCNT cathodes towards the hydrogen evolution reaction (HER) is dependent on PLA time and shows a maximum at tPLA = 40 min. EIS measurements revealed that the HER response is characterized by a two time constants process representing HER kinetics and adsorption of hydrogen.

  5. Optimization of the interface polarization of the La{sub 2}NiO{sub 4}-based cathode working with the Ce{sub 1-x}Sm{sub x}O{sub 2-{delta}} electrolyte system

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Coll, D.; Aguadero, A.; Escudero, M.J. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Av. Complutense 22, 28040 Madrid (Spain); Nunez, P. [Dpto. Quimica Inorganica, Universidad de La Laguna, 38200 La Laguna, Tenerife (Spain); Daza, L. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Av. Complutense 22, 28040 Madrid (Spain); Instituto de Catalisis y Petroleoquimica (CSIC), Marie-Curie 2, Campus Cantoblanco, 28049 Madrid (Spain)

    2008-03-15

    The performance of La{sub 2}NiO{sub 4} cathode material and Ce{sub 1-x}Sm{sub x}O{sub 2-{delta}} (x = 0.1, 0.2, 0.3, 0.4) electrolyte system was analyzed. Ceria-based materials were prepared by the freeze-drying precursor route whereas La{sub 2}NiO{sub 4} was prepared by the nitrate-citrate procedure. Electrolyte pellets were obtained after sintering the powders at 1600 C for 10 h. Also dense ceria-based electrolytes samples were obtained by calcining the powders at 1150 C after the addition of 2 mol%-Co. Interface polarization measurements were performed by impedance spectroscopy in air at open circuit voltage, using symmetrical cells prepared after the deposition of porous La{sub 2}NiO{sub 4}-electrodes on the Ce{sub 1-x}Sm{sub x}O{sub 2-{delta}} system. X-ray diffraction (XRD) of cathode materials after using in symmetrical cells confirmed no significant reaction between La{sub 2}NiO{sub 4} and ceria-based electrolytes. The efficiency of the cathode material is highly dependent on the composition of the electrolyte, and low-content Sm-doped ceria samples revealed an important decrease in the performance of the system. Differences in electrochemical behaviour were attributed principally to the oxide ion transference between cathode and electrolyte, and were correlated to the conductivity of the electrolyte. In this way cobalt-doped electrolytes with a Sm-content {<=}30% perform better than free-cobalt samples due to the increase in grain boundary conductivity. Finally, composites of the ceria-based materials and La{sub 2}NiO{sub 4} to use as cathode were prepared and an important increase of the interface performance was observed compared to La{sub 2}NiO{sub 4} pure cathode. Predictions of maximun power density were obtained by the mixed transport properties of the electrolytes and by the interface polarization results. The use of composite materials could allow to increase the performance of the cell from 170 mW cm{sup -2} for pure La{sub 2}NiO{sub 4} cathode

  6. Final Report - Advanced Cathode Catalysts and Supports for PEM Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Debe, Mark

    2012-09-28

    The principal objectives of the program were development of a durable, low cost, high performance cathode electrode (catalyst and support), that is fully integrated into a fuel cell membrane electrode assembly with gas diffusion media, fabricated by high volume capable processes, and is able to meet or exceed the 2015 DOE targets. Work completed in this contract was an extension of the developments under three preceding cooperative agreements/grants Nos. DE-FC-02-97EE50473, DE-FC-99EE50582 and DE-FC36- 02AL67621 which investigated catalyzed membrane electrode assemblies for PEM fuel cells based on a fundamentally new, nanostructured thin film catalyst and support system, and demonstrated the feasibility for high volume manufacturability.

  7. Electrolytic Fixation of CO2 by Electrocarboxylation of RX on Nanocrystalline TiO2-Pt Cathode

    Institute of Scientific and Technical Information of China (English)

    CHU, Dao-Bao(褚道葆); LI, Xiao-Hua(李晓华); LIU, Xin-Yuan(刘心元); YAO, Wen-Li(姚文俐)

    2004-01-01

    Electrolytic fixation of CO2 was investigated by electrocarboxylation of organic halides (RX), and four esters (Ⅰ, Ⅱ, Ⅲ, Ⅳ) were obtained in moderate yields. Electrochemical reduction esterifications of RX in the presence of CO2 were carried out on nanocrystalline TiO2-Pt electrode. The electrochemical behavior of RX in the presence of CO2 was investigated by the technique of cyclic voltammetry, and the probable reaction mechanism was proposed.

  8. Behaviour of the 1-Ascorbic as supporting Electrolyte. Influence of the Magnesium Ion; Comportamiento del acido 1-Ascorbico como electrolito soporte influencai del ion magnesio

    Energy Technology Data Exchange (ETDEWEB)

    Alonso Lopez, J.

    1962-07-01

    The behaviour of 1-ascorbic acid, as supporting electrolyte of the uranyl ion in a 0{sub 1}-0.7 M concentration range, and the influence of pH on the diffusion current and half wave potential of 0,1 M uranyl ion is studied. The cathodic waves from 0 to -2,5 volts, with mercury dropping electrode are studied in fresh 0,1 M aqueous solution in presence of Mg{sup 2}+ and at 2,0-12 pH range. A kinetic current with a half wave potential of 0,85 v. vs. Hg. b.e. is obtained at pH> 9,5 appears a tilth wave a -0,60 v. The pH variation does not influence these potentials. (Author) 18 refs.

  9. Cathodic reduction of sulfur dioxide in nonaqueous electrolytes. The effect of solution composition on the diffusion coefficient of sulfur dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Shembel, E.M.; Ksenzhek, O.S.; Lituinova, V.I.; Lobach, G.A.

    1986-09-01

    The authors measured the diffusion coefficients of SO/sub 2/ in electrolytes based on propylene carbonate, acetonitrile, dimethylformamide and dimethylsulfoxide in order to estimate possible diffusion limitations with respect to SO/sub 2/ and to establish the influence exerted by the solvent type on the process. The diffusion coefficients were calculated from the limiting diffusion currents of steady-state polarization curves for sulfur dioxide reduction recorded at a gold microdisk electrode which had a diameter of 2 x 10/sup -3/ cm. In lithium salt solutions the potentiodynamic curves recorded at the microelectrode do not exhibit a limiting current but are characterized by a current maximum.

  10. On the crucial influence of some supporting electrolytes during electrocoagulation in the presence of aluminum electrodes.

    Science.gov (United States)

    Trompette, J L; Vergnes, H

    2009-04-30

    The influence of some supporting electrolytes on aluminum electrode oxidation and pH variation during electrocoagulation of an unskimmed milk sample and a cutting oil emulsion has been investigated. Among the electrolytes studied, sulfate anions were found to be quite harmful both for electrical consumption and electrocoagulation efficiency. At the opposite, chloride and ammonium ions were particularly benefic respectively for aluminum corrosion and pH regulation, whereas sodium cations were observed to have a neutral role. The results indicate that electrocoagulation can be realized at low anodic potential even in the presence of sulfate ions when the [Cl(-)]/[SO(4)(2-)] ratio is around or greater than 1/10. The detrimental effect of sulfates on electrocoagulation efficiency can be thwarted by the use of the ammonium salt thanks to its related buffer effect.

  11. 室温离子液体电解质与锂离子电池正极材料的相容性%Compatibility of Room Temperature Ionic Electrolytes with Cathode Materials in Li-ion Batteries

    Institute of Scientific and Technical Information of China (English)

    郑洪河; 刘云伟; 曲群婷; 石静

    2007-01-01

      Room temperature ionic liquids are known as new functional soft media materials, their electrochemical properties are attracting wide attention throughout the world. This paper reviews the research status of the compatibility of room temperature ionic electrolyte with cathode materials in lithium ion batteries. The basic principles relating to the compatibility are summarized. The two ways for improving the compatibility between ionic electrolytes and cathode materials are discussed in terms of cathode material modification and electrolyte optimization.%  室温离子液体作为新一代软功能介质材料,其电化学性质正在引起人们的广泛关注。本文综述了室温离子液体电解质在用于锂离子电池时与正极材料相容性的研究状况,总结了不同室温离子液体电解质与锂离子电池正极材料相容性的基本规律,从正极材料和室温离子液体两个方面探讨了改善室温离子液体/正极材料相容性的基本途径。

  12. A Critical Review of Published Data on the Gas Temperature and the Electron Density in the Electrolyte Cathode Atmospheric Glow Discharges

    Directory of Open Access Journals (Sweden)

    Tamás Cserfalvi

    2012-05-01

    Full Text Available Electrolyte Cathode Discharge (ELCAD spectrometry, a novel sensitive multielement direct analytical method for metal traces in aqueous solutions, was introduced in 1993 as a new sensing principle. Since then several works have tried to develop an operational mechanism for this exotic atmospheric glow plasma technique, however these attempts cannot be combined into a valid model description. In this review we summarize the conceptual and technical problems we found in this upcoming research field of direct sensors. The TG gas temperature and the ne electron density values published up to now for ELCAD are very confusing. These data were evaluated by three conditions. The first is the gas composition of the ELCAD plasma, since TG was determined from the emitted intensity of the N2 and OH bands. Secondly, since the ELCAD is an atmospheric glow discharge, thus, the obtained TG has to be close to the Te electron temperature. This can be used for the mutual validation of the received temperature data. Thirdly, as a consequence of the second condition, the values of TG and ne have to agree with the Engel-Brown approximation of the Saha-equation related to weakly ionized glow discharge plasmas. Application of non-adequate experimental methods and theoretical treatment leads to unreliable descriptions which cannot be used to optimize the detector performance.

  13. Composite polymer electrolyte membranes supported by non-woven fabrics for lithium-ion polymer batteries

    Institute of Scientific and Technical Information of China (English)

    TANG Dingguo; LIU Jianhong; QI Lu; CHEN Hui; CI Yunxiang

    2005-01-01

    Poly(vinylidene fluoride-co-hexafluoropropyle- ne) (PVDF-HFP) is one of the most popular polymers for polymer electrolyte membranes because of its excellent operating characteristics and superior electrochemical properties. The electrochemical performances of polymer electrolyte membrane can be enhanced by evenly dispersing nano-meter SiO2 particles in the polymer. In this paper, non-woven fabrics were immersed in the mixed solution of PVDF-HFP/ SiO2/butanone/butanol/plasticizer, and then dried in a vacuum oven to remove the solvents and the plasticizer and to make porous composite polymer electrolyte membranes. The prepared composite membranes supported by non-woven fabrics boast good mechanical strength and excellent electrochemical properties: the electrochemical stability window is 4.8 V vs. Li+/Li, and the ionic conductivity is 3.35×10-4 S/cm (around 60% of that of a common PE membrane) at room temperature. The lithium-ion polymer battery assembled by the composite membrane exhibits high rate capability and excellent cycling performance.

  14. Neutron scattering study on cathode LiMn{sub 2}O{sub 4} and solid electrolyte 5(Li{sub 2}O)(P{sub 2}O{sub 5})

    Energy Technology Data Exchange (ETDEWEB)

    Kartini, E., E-mail: kartini@batan.go.id; Putra, Teguh P., E-mail: kartini@batan.go.id; Jahya, A. K., E-mail: kartini@batan.go.id; Insani, A., E-mail: kartini@batan.go.id [Technology Center for Nuclear Industry Materials, National Nuclear Energy Agency, Serpong 15314 (Indonesia); Adams, S. [Department of Materials Science and Engineering, National University of Singapore, Singapore-117576 (Singapore)

    2014-09-30

    Neutron scattering is very important technique in order to investigate the energy storage materials such as lithium-ion battery. The unique advantages, neutron can see the light atoms such as Hydrogen, Lithium, and Oxygen, where those elements are negligible by other corresponding X-ray method. On the other hand, the energy storage materials, such as lithium ion battery is very important for the application in the electric vehicles, electronic devices or home appliances. The battery contains electrodes (anode and cathode), and the electrolyte materials. There are many challenging to improve the existing lithium ion battery materials, in order to increase their life time, cyclic ability and also its stability. One of the most scientific challenging is to investigate the crystal structure of both electrode and electrolyte, such as cathodes LiCoO{sub 2}, LiMn{sub 2}O{sub 4} and LiFePO{sub 4}, and solid electrolyte Li{sub 3}PO{sub 4}. Since all those battery materials contain Lithium ions and Oxygen, the used of neutron scattering techniques to study their structure and related properties are very important and indispensable. This article will review some works of investigating electrodes and electrolytes, LiMn{sub 2}O{sub 4} and 5(Li{sub 2}O)(P{sub 2}O{sub 5}), by using a high resolution powder diffraction (HRPD) at the multipurpose research reactor, RSG-Sywabessy of the National Nuclear Energy Agency (BATAN), Indonesia.

  15. Carbon Supported Ag Nanoparticles as High Performance Cathode Catalyst for Anion Exchange Membrane Fuel Cell

    Directory of Open Access Journals (Sweden)

    Le eXin

    2013-09-01

    Full Text Available A solution phase-based nanocapsule method was successfully developed to synthesize non-precious metal catalyst - carbon supported Ag nanoparticles (Ag/C. XRD patterns and TEM image show Ag nanoparticles with a small average size (5.4 nm and narrow size distribution (2-9 nm are uniformly dispersed on the carbon black Vulcan XC-72 support. The intrinsic activity and pathway of oxygen reduction reaction (ORR on the Ag/C and commercial Pt/C were investigated using rotating ring disc electrode (RRDE tests at room temperature. The results confirmed that the 4-electron pathway of ORR proceeds on small Ag nanoparticles, and showed comparable ORR activities on the self-prepared Ag/C and a commercial Pt/C. A single H2-O2 anion exchange membrane fuel cell with the Ag/C cathode catalyst exhibited an open circuit potential of 0.98 V and a peak power density of 190 mW/cm2 at 80 oC.

  16. Evaluation of the La{sub 2}Ni{sub 1} {sub -} {sub x}Cu{sub x}O{sub 4} {sub +} {sub {delta}} system as SOFC cathode material with 8YSZ and LSGM as electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Aguadero, A.; Escudero, M.J. [Centro de Investigaciones Energeticas Mediambientales y Tecnologicas (CIEMAT), Av. Complutense 22, 28040 Madrid (Spain); Alonso, J.A. [Instituto de Ciencia de Materiales de Madrid (CSIC),C/Sor Juana Ines de la Cruz 3, Campus Cantoblanco, 28049 Madrid (Spain); Daza, L. [Centro de Investigaciones Energeticas Mediambientales y Tecnologicas (CIEMAT), Av. Complutense 22, 28040 Madrid (Spain); Instituto de Catalisis y Petroleoquimica,(CSIC), C/Marie Curie 2, Campus Cantoblanco, 28049 Madrid (Spain)

    2008-05-31

    Materials formulated as La{sub 2}Ni{sub 1} {sub -} {sub x}Cu{sub x}O{sub 4} {sub +} {sub {delta}} (0 {<=} x {<=} 1) have been synthesised to be evaluated as possible cathode materials in SOFCs. Their crystal structures have been investigated by high-resolution neutron powder diffraction at RT so as to map out the phase diagram. The thermal expansion coefficients have been determined to be in the range of 10.8-13.0 x 10{sup -} {sup 6} K{sup -} {sup 1}. Total conductivity values are as good as 87 S cm{sup -} {sup 1} at 580 C for x = 0.4. In order to assess the performance of each oxide as cathode material, ac impedance measurements were carried out on La{sub 2}Ni{sub 1} {sub -} {sub x}Cu{sub x}O{sub 4} {sub +} {sub {delta}}/electrolyte/La{sub 2}Ni{sub 1} {sub -} {sub x}Cu{sub x}O{sub 4} {sub +} {sub {delta}} symmetrical cells with either LSGM or 8YSZ as electrolyte material. For all the electrode compositions studied, the best specific resistance (ASR) values were obtained with LSGM as electrolyte. The better performance of x = 0.4 and 0.6 (ASR {proportional_to} 1 and ohm; cm{sup 2} at 850 C) compositions has been associated with the magnitude of the total conductivity and the matching of the TEC values of the cathodes with those of the electrolytes. (author)

  17. Influence of pore formers on physical properties and microstructures of supporting cathodes of solid oxide electrolysis cells

    Energy Technology Data Exchange (ETDEWEB)

    Mingyi, Liu; Bo, Yu.; Jingming, Xu; Jing, Chen [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China)

    2010-04-15

    High-temperature steam electrolysis (HTSE) systems using solid oxide electrolysis cells (SOECs) provided a promising method for highly efficient large-scale hydrogen production, which was one of the most potential hydrogen production technologies to meet the hydrogen economy demand in the future. The physical properties and microstructures of supporting cathodes are crucial for the performances of the entire SOECs. For this reason, four different pore formers (polymethyl methacrylate (PMMA), potato starch, ammonium oxalate, ammonium carbonate) were considered for its optimization. Their influence on the amount of porosity and on the pore shape and distribution as well as the effect on the electronic conductivity was analyzed. The results showed that PMMA was the most promising pore former, which had high porosity and uniform pore size distribution. The optimum weight percent concentration was 10%, correspondingly, porosity was 45% and electronic conductivity was 6726S cm{sup -1}, which was suitable for supporting cathodes for SOEC application. The pore former of potato starch was better than the inorganic pore formers of ammonium oxalate and ammonium carbonate. The optimum weight percent concentration was 10%, correspondingly, porosity was 40% and electronic conductivity was 5827S cm{sup -1}, which was not suitable for supporting cathodes for SOEC application, while, It was suitable for supporting anodes for SOFC application. (author)

  18. Poly(methyl methacrylate-acrylonitrile-ethyl acrylate) terpolymer based gel electrolyte for LiNi0.5Mn1.5O4 cathode of high voltage lithium ion battery

    Science.gov (United States)

    Sun, Ping; Liao, Youhao; Xie, Huili; Chen, Tingting; Rao, Mumin; Li, Weishan

    2014-12-01

    A novel gel polymer electrolyte (GPE), based on poly(methyl methacrylate-acrylonitrile-ethyl acrylate) (P(MMA-AN-EA)) terpolymer, is designed to match LiNi0.5Mn1.5O4 cathode of 5 V lithium ion battery. The performances of the synthesized P(MMA-AN-EA) terpolymer and the corresponding membrane and GPE are investigated by scanning electron microscope, energy dispersive spectroscopy, nuclear magnetic resonance spectra, Fourier transform infrared spectra, thermogravimetric analyzer, electrochemical impedance spectroscopy, linear sweep voltammetry, and charge/discharge test. It is found that the pore structure of P(MMA-AN-EA) membrane is affected by the dose of pore forming agent, polyethylene glycol (PEG400). The membrane with 3 wt% PEG400 presents the best pore structure, in which pores are dispersed uniformly and interconnected, and exhibits the largest electrolyte uptake, resulting in the highest ionic conductivity of 3.82 × 10-3 S cm-1 for the corresponding GPE at room temperature. The GPE has improved compatibility with lithium anode and is electrochemically stable up to 5.2 V (vs. Li/Li+). The high voltage LiNi0.5Mn1.5O4 cathode using the resulting GPE exhibits excellent cyclic stability, maintaining 97.9% of its initial discharge capacity after 100 cycles compared to that of 79.7% for the liquid electrolyte at 0.5 C.

  19. Fabrication of bilayered YSZ/SDC electrolyte film by electrophoretic deposition for reduced-temperature operating anode-supported SOFC

    Science.gov (United States)

    Matsuda, Motohide; Hosomi, Takushi; Murata, Kenji; Fukui, Takehisa; Miyake, Michihiro

    Bilayered Y 2O 3-stabilized ZrO 2 (YSZ)/Sm 2O 3-doped CeO 2 (SDC) electrolyte films were successfully fabricated on porous NiO-YSZ composite substrates by electrophoretic deposition (EPD) based on electrophoretic filtration followed by co-firing with the substrates. In EPD, positively charged YSZ and SDC powders were deposited directly on the substrates, layer by layer from ethanol-based suspensions. Delamination between YSZ and SDC films was avoided by reducing the SDC films' thickness to ca. 1 μm. A single cell was constructed on the bilayered electrolyte films composed of ca. 4 μm-thick YSZ and ca. 1 μm-thick SDC films. As a cathode in the cell, La 0.6Sr 0.4Co 0.2Fe 0.8O 3- x (LSCF) was used. Maximum output power densities greater than 0.6 W cm -2 were obtained at 700 °C for the bilayered YSZ/SDC electrolyte cells thus constructed.

  20. Fabrication of bilayered YSZ/SDC electrolyte film by electrophoretic deposition for reduced-temperature operating anode-supported SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, Motohide; Hosomi, Takushi; Miyake, Michihiro [Graduate School of Environmental Science, Okayama University, 3-1-1 Tsushima-Naka, Okayama 700-8530 (Japan); Murata, Kenji; Fukui, Takehisa [Hosowaka Powder Technology Research Institute, 1-9 Shoudai, Tajika, Hirakata, Osaka 573-1132 (Japan)

    2007-02-25

    Bilayered Y{sub 2}O{sub 3}-stabilized ZrO{sub 2} (YSZ)/Sm{sub 2}O{sub 3}-doped CeO{sub 2} (SDC) electrolyte films were successfully fabricated on porous NiO-YSZ composite substrates by electrophoretic deposition (EPD) based on electrophoretic filtration followed by co-firing with the substrates. In EPD, positively charged YSZ and SDC powders were deposited directly on the substrates, layer by layer from ethanol-based suspensions. Delamination between YSZ and SDC films was avoided by reducing the SDC films' thickness to ca. 1 {mu}m. A single cell was constructed on the bilayered electrolyte films composed of ca. 4 {mu}m-thick YSZ and ca. 1 {mu}m-thick SDC films. As a cathode in the cell, La{sub 0.6}Sr{sub 0.4}Co{sub 0.2}Fe{sub 0.8}O{sub 3-x} (LSCF) was used. Maximum output power densities greater than 0.6 W cm{sup -2} were obtained at 700 C for the bilayered YSZ/SDC electrolyte cells thus constructed. (author)

  1. FTIR and Raman Study of the LixTiyMn1-yO2 (y = 0, 0.11) Cathodes in Methylpropyl Pyrrolidinium Bis(fluoro-sulfonyl)imide, LiTFSI Electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Hardwick, L.J.; Lucas, I.T.; Doeff, M.M.; Kostecki, R.; Saint, J.A.

    2009-02-02

    This work demonstrates the protective effect of partial titanium substitution in Li{sub x}Ti{sub 0.11}Mn{sub 0.89}O{sub 2} against surface decomposition in room-temperature ionic liquid (RTILs) cells. Raman microscopy and reflectance Fourier transform IR (FTIR) spectroscopy were used to analyze electrodes recovered from cycled Li/Li{sub x}Ti{sub y}Mn{sub 1-y}O{sub 2} (y=0, 0.11) cells containing the 0.5 mol/kg LiTFSI in P{sub 13}FSI RTIL electrolyte. [TFSI=bis(trifluoromethanesulfonyl)imide.] Raman and FTIR spectra of cycled Li{sub x}MnO{sub 2} cathodes showed many distinct bands that can be attributed to both the electrolyte and electrode decomposition products. The thickness of the amorphous porous layer on the Li{sub x}MnO{sub 2} cathode increased during cycling. The surface degradation of Li{sub x}MnO{sub 2} and precipitation of electrolyte decomposition products contributed to the film growth. Improved cycling behavior was observed in cells containing Li{sub x}Ti{sub 0.11}Mn{sub 0.89}O{sub 2}, yet Raman spectroscopy also showed possible surface degradation. The FTIR spectra of cycled Li{sub x}MnO{sub 2} and Li{sub x}Ti{sub 0.11}Mn{sub 0.89}O{sub 2} cathodes displayed bands characteristic for LiSO{sub 3}CF{sub 3} and Li{sub 2}NSO{sub 2}CF{sub 3}, which originate from the reaction of the TFSI anion with traces of water present in the cell.

  2. Actinide-Lanthanide separation by an electrolytic method in molten salt media: feasibility assessment of a renewed liquid cathode; Un nouveau concept de separation actinides-lanthanides en milieu sel fondu: mise en oeuvre d'une cathode liquide a surface renouvelee

    Energy Technology Data Exchange (ETDEWEB)

    Huguet, A.

    2009-12-15

    This study is part of a research program concerning the assessment of pyrochemical methods for the nuclear waste processing. The An-Ln partitioning could be achieved by an electrolytic selective extraction in molten salt media. It has been decided to focus on liquid reactive cathode which better suits to a group actinides co-recycling. The aim of the study is to propose, define and initiate the development of an electrolytic pyro-process dedicated to the quantitative and selective recovery of the actinides. Quantitativeness is related to technology, whereas selectivity is governed by chemistry. The first step consisted in selecting the adequate operating conditions, which enables a sufficient An-Ln separation. The first step consisted, by means of thermodynamic calculi and electrochemical investigations, in selecting a promising combination between molten electrolyte and cathodic material, regarding the process constraints. To improve the recovery yield, it is necessary to develop a disruptive technology: here comes the concept of a dynamic electrodeposition carried out onto liquid metallic drops. The next step consisted in designing and manufacturing a lab-scale device which enables dropping flow studies. Since interfacial phenomena are of primary meaning in such a concept, it has been decided to focus on high temperature liquid-liquid interfacial measurements. (author)

  3. Electrophoretic deposition of thin SOFC-electrolyte films on porous La{sub 0,75}Sr{sub 0,2}MnO{sub 3-{delta}} cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Argirusis, C.; Damjanovic, T.; Borchardt, G. [Technische Univ. Clausthal, Fachbereich Physik, Metallurgie und Werkstoffwissenschaften, Clausthal-Zellerfeld (Germany)

    2004-07-01

    Solid oxide fuel cells with an electrode supported thin film electrolyte (electrolyte thickness 5 {mu}m < d < 20 {mu}m) are a promising alternative to electrolyte supported single cells because of decreased electrolyte resistance. The electrophoretic deposition (EPD) was performed on A-site deficient La{sub 0.75}Sr{sub 0.2}MnO{sub 3-{delta}} (ULSM) from three different suspensions: (Y{sub 2}O{sub 3}){sub 0.08}(ZrO{sub 2}){sub 0.92} (YSZ), (Ce{sub 0.9}Gd{sub 0.1})O{sub 1.955} (GDC) and La{sub 0.9}Sr{sub 0.1}Ga{sub 0.8}Mg{sub 0.2}O{sub 2.85} (LSGM) in acetylacetone and isopropanol. The thickness of the deposits was controlled by varying the conditions of the electrophoretic deposition. (orig.)

  4. Evaluating focused ion beam and ultramicrotome sample preparation for analytical microscopies of the cathode layer of a polymer electrolyte membrane fuel cell

    Science.gov (United States)

    de A. Melo, Lis G.; Hitchcock, Adam P.; Berejnov, Viatcheslav; Susac, Darija; Stumper, Juergen; Botton, Gianluigi A.

    2016-04-01

    Optimizing the structure of the porous electrodes of polymer electrolyte membrane fuel cells (PEM-FC) can improve device power and durability. Analytical microscopy techniques are important tools for measuring the electrode structure, thereby providing guidance for structural optimization. Transmission Electron Microscopy (TEM), with either Energy Dispersive X-Ray (EDX) or Electron Energy Loss Spectroscopy (EELS) analysis, and Scanning Transmission X-Ray Microscopy (STXM) are complementary methods which, together, provide a powerful approach for PEM-FC electrode analysis. Both TEM and STXM require thin (50-200 nm) samples, which can be prepared either by Focused Ion Beam (FIB) milling or by embedding and ultramicrotomy. Here we compare TEM and STXM spectromicroscopy analysis of FIB and ultramicrotomy sample preparations of the same PEM-FC sample, with focus on how sample preparation affects the derived chemical composition and spatial distributions of carbon support and ionomer. The FIB lamella method, while avoiding pore-filling by embedding media, had significant problems. In particular, in the FIB sample the carbon support was extensively amorphized and the ionomer component suffered mass loss and structural damage. Although each sample preparation technique has a role to play in PEM-FC optimization studies, it is important to be aware of the limitations of each method.

  5. Design and test status for life support applications of SPE oxygen generation systems. [Solid Polymer Electrolyte

    Science.gov (United States)

    Titterington, W. A.; Erickson, A. C.

    1975-01-01

    An advanced six-man rated oxygen generation system has been fabricated and tested as part of a NASA/JSC technology development program for a long lived, manned spacecraft life support system. Details of the design and tests results are presented. The system is based on the Solid Polymer Electrolyte (SPE) water electrolysis technology and its nominal operating conditions are 2760 kN/sq m (400 psia) and 355 K (180 F) with an electrolysis module current density capability up to 350 mA/sq cm (326 ASF). The system is centered on a 13-cell SPE water electrolysis module having a single cell active area of 214 sq cm (33 sq in) and it incorporates instrumentation and controls for single pushbutton automatic startup/shutdown, component fault detection and isolation, and self-contained sensors and controls for automatic safe emergency shutdown. The system has been tested in both the orbital cyclic and continuous mode of operation. Various parametric tests have been completed to define the system capability for potential application in spacecraft environmental systems.

  6. Phase behaviour and conductivity of supporting electrolytes in supercritical difluoromethane and 1,1-difluoroethane.

    Science.gov (United States)

    Han, Xue; Ke, Jie; Suleiman, Norhidayah; Levason, William; Pugh, David; Zhang, Wenjian; Reid, Gillian; Licence, Peter; George, Michael W

    2016-06-01

    We present investigations into a variety of supporting electrolytes and supercritical fluids probing the phase and conductivity behaviour of these systems and show that they not only provide sufficient electrical conductivity for an electrodeposition bath, but match the requirements imposed by the different precursors and process parameters, e.g. increased temperature, for potential deposition experiments. The two supercritical fluids that have been explored in this study are difluoromethane (CH2F2) and 1,1-difluoroethane (CHF2CH3). For CH2F2, the phase behaviour and electrical conductivity of eight ionic compounds have been studied. Each compound consists of a cation and an anion from the selected candidates i.e. tetramethylammonium ([N(CH3)4](+)), tetrabutylammonium ([N((n)C4H9)4](+)), 1-ethyl-3-methylimidazolium ([EMIM](+)) and 1-butyl-3-methylimidazolium ([BMIM](+)) for cations, and tetrakis(perfluoro-tert-butoxy)aluminate ([Al(OC(CF3)3)4](-)), chloride (Cl(-)), trifluoromethyl sulfonimide ([NTf2](-)) and tris(pentafluoroethyl)trifluorophosphate ([FAP](-)) for anions. For CHF2CH3, [N((n)C4H9)4][BF4] and [N((n)C4H9)4][B{3,5-C6H3(CF3)2}4] have been investigated for comparison with the previously measured solubility and conductivity in CH2F2. We have found that [N((n)C4H9)4][Al(OC(CF3)3)4], [N((n)C4H9)4][FAP] and [N(CH3)4][FAP] have much higher molar conductivity in scCH2F2 at similar conditions than [N((n)C4H9)4][BF4], a widely used commercial electrolyte. Additionally, scCHF2CH3 shows potential for use as the solvent for supercritical fluid electrodeposition, especially at high temperatures since high density of this fluid can be achieved at lower operating pressures than similar fluids that can be used to produce electrochemical baths with comparable conductivity.

  7. A novel imidazole-based electrolyte additive for improved electrochemical performance at elevated temperature of high-voltage LiNi0.5Mn1.5O4 cathodes

    Science.gov (United States)

    Rong, Haibo; Xu, Mengqing; Xie, Boyuan; Lin, Haibin; Zhu, Yunmin; Zheng, Xiongwen; Huang, Weizhao; Liao, Youhao; Xing, Lidan; Li, Weishan

    2016-10-01

    A novel electrolyte additive, 1,1‧-sulfonyldiimidazole (SDM), is firstly reported to improve the cycling performance of LiNi0.5Mn1.5O4 at high voltage and elevated temperature (55 °C). Linear sweep voltammetry (LSV), initial differential capacity vs. voltage, and computation results indicate that SDM is oxidized at a lower potential than the solvents of the electrolyte. Coulombic efficiency and capacity retention of a Li/LiNi0.5Mn1.5O4 cell can be significantly enhanced in the presence of SDM, and moreover cells with SDM deliver lower impedance after 100 cycles at elevated temperature. To better understand the functional mechanism of the enhanced performance with incorporation of SDM in the electrolyte, ex-situ analytical techniques, including scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and inductively coupled plasma mass spectrometry (ICP-MS) are employed to gain insight into the reaction mechanism of SDM on the LiNi0.5Mn1.5O4 electrode at high voltage and elevated temperature (55 °C). Surface analysis reveals that the improved electrochemical performance of the cells can be ascribed to the highly stable surface layer generated by SDM, which thus mitigates the detrimental decomposition of the electrolyte occurring and stabilizes the interphase of spinel LiNi0.5Mn1.5O4 cathode while cycling at high voltage and elevated temperature.

  8. Fabrication of anode-supported zirconia thin film electrolyte based core-shell particle structure for intermediate temperature solid oxide fuel cells

    Institute of Scientific and Technical Information of China (English)

    Peng Li; John T.S.Irvinen

    2013-01-01

    With a view to produce intermediate temperature SOFCs, yttria and scandia doped zirconia with a core-shell structure was prepared, then an anode supported fuel cell was fabricated by a spray method. The influences of the scandia content in the electrolyte and atmosphere conditions used in the testing experiments on phase composition, microstructure and fuel cell performance were investigated. The electrolyte was composed of cubic and tetragonal phases and SEM pictures revealed very fine grain sizes and a smooth surface of the electrolyte film, though some defects were observed in samples with high Scandia content. Coating scandia on partially stabilized zirconium particles improves both ionic conductivity of the electrolyte and power density of the fuel cell distinctly below 750 1C. Anodes were pre-sintered at 1200 1C before co-sintering with the electrolyte film to ensure that the shrinkage percentage was close to that of the electrolyte during co-sintering, avoiding warping of cell.

  9. Influence of Electrode Design and Contacting Layers on Performance of Electrolyte Supported SOFC/SOEC Single Cells

    Directory of Open Access Journals (Sweden)

    Mihails Kusnezoff

    2016-11-01

    Full Text Available The solid oxide cell is a basis for highly efficient and reversible electrochemical energy conversion. A single cell based on a planar electrolyte substrate as support (ESC is often utilized for SOFC/SOEC stack manufacturing and fulfills necessary requirements for application in small, medium and large scale fuel cell and electrolysis systems. Thickness of the electrolyte substrate, and its ionic conductivity limits the power density of the ESC. To improve the performance of this cell type in SOFC/SOEC mode, alternative fuel electrodes, on the basis of Ni/CGO as well as electrolytes with reduced thickness, have been applied. Furthermore, different interlayers on the air side have been tested to avoid the electrode delamination and to reduce the cell degradation in electrolysis mode. Finally, the influence of the contacting layer on cell performance, especially for cells with an ultrathin electrolyte and thin electrode layers, has been investigated. It has been found that Ni/CGO outperform traditional Ni/8YSZ electrodes and the introduction of a ScSZ interlayer substantially reduces the degradation rate of ESC in electrolysis mode. Furthermore, it was demonstrated that, for thin electrodes, the application of contacting layers with good conductivity and adhesion to current collectors improves performance significantly.

  10. Stainless steel mesh supported nitrogen-doped carbon nanofibers for binder-free cathode in microbial fuel cells.

    Science.gov (United States)

    Chen, Shuiliang; Chen, Yu; He, Guanghua; He, Shuijian; Schröder, Uwe; Hou, Haoqing

    2012-04-15

    In this communication, we report a binder-free oxygen reduction cathode for microbial fuel cells. The binder-free cathode is prepared by growth of nitrogen-doped carbon nanofibers (NCNFs) on stainless steel mesh (SSM) via simple pyrolysis of pyridine. The interaction force between NCNFs and SSM surface is very strong which is able to tolerate water flush. The NCNFs/SSM cathode shows high and stable electrocatalytic activity for oxygen reduction reaction, which is comparable to that of Pt/SSM and ferricyanide cathode. This study proposes a promising low-cost binder-free cathode for microbial fuel cells.

  11. Plasma-enhanced atomic layer deposition of nanoscale yttria-stabilized zirconia electrolyte for solid oxide fuel cells with porous substrate.

    Science.gov (United States)

    Ji, Sanghoon; Cho, Gu Young; Yu, Wonjong; Su, Pei-Chen; Lee, Min Hwan; Cha, Suk Won

    2015-02-11

    Nanoscale yttria-stabilized zirconia (YSZ) electrolyte film was deposited by plasma-enhanced atomic layer deposition (PEALD) on a porous anodic aluminum oxide supporting substrate for solid oxide fuel cells. The minimum thickness of PEALD-YSZ electrolyte required for a consistently high open circuit voltage of 1.17 V at 500 °C is 70 nm, which is much thinner than the reported thickness of 180 nm using nonplasmatic ALD and is also the thinnest attainable value reported in the literatures on a porous supporting substrate. By further reducing the electrolyte thickness, the grain size reduction resulted in high surface grain boundary density at the cathode/electrolyte interface.

  12. Progress of Cathode Material and Electrolyte in Non-aqueous Li-Air Battery%非水系锂空气电池的正极材料和电解液研究进展

    Institute of Scientific and Technical Information of China (English)

    杨凤玉; 张蕾蕾; 徐吉静; 刘清朝; 赵敏寿; 张新波

    2013-01-01

    A Li-air battery could provide much higher energy density than conventional lithium-ion battery,which is comparable to gasoline and,thus,many attentions have been paid to the Li-air battery in recent years.This paper summarizes the latest development of the cathode material and electrolyte in the non-aqueous Li-air battery.The cathode materials concern commercial carbon,artificial carbon with a defined morphology,catalyst and conducting polymer.Electrolytes concern widely used solvents including ester,ether,sulfone,amine and ionic liquid.Finally,the main problems in the non-aqueous Li-air battery have been pointed out and look forward to the future on non-aqueous Li-air battery.%锂空气电池的能量密度是传统锂离子电池的5~10倍,可与汽油相媲美.近几年来,锂空气电池因此受到了人们的广泛关注.本文概述了锂空气电池正极材料和电解液的最新研究进展.从商业碳、具有特定形态的碳材料、催化剂、导电聚合物等几个方面阐述了正极材料;从物质结构的角度,简要介绍了锂空气电池中常用的酯类、醚类、砜类、胺类和离子液体等电解液.最后指出了目前锂空气电池存在的问题,并对其进行了展望.

  13. Fundamental Investigations and Rational Design of Durable High-Performance SOFC Cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yu [Georgia Inst. of Technology, Atlanta, GA (United States); Ding, Dong [Georgia Inst. of Technology, Atlanta, GA (United States); Wei, Tao [Georgia Inst. of Technology, Atlanta, GA (United States); Liu, Meilin [Georgia Inst. of Technology, Atlanta, GA (United States)

    2016-03-31

    The main objective of this project is to unravel the degradation mechanism of LSCF cathodes under realistic operating conditions with different types of contaminants, aiming towards the rational design of cathodes with high-performance and enhanced durability by combining a porous backbone (such as LSCF) with a thin catalyst coating. The mechanistic understanding will help us to optimize the composition and morphology of the catalyst layer and microstructure of the LSCF backbone for better performance and durability. More specifically, the technical objectives include: (1) to unravel the degradation mechanism of LSCF cathodes under realistic operating conditions with different types of contaminants using in situ and ex situ measurements performed on specially-designed cathodes; (2) to examine the microstructural and compositional evolution of LSCF cathodes as well as the cathode/electrolyte interfaces under realistic operating conditions; (3) to correlate the fuel cell performance instability and degradation with the microstructural and morphological evolution and surface chemistry change of the cathode under realistic operating conditions; (4) to explore new catalyst materials and electrode structures to enhance the stability of the LSCF cathode under realistic operating conditions; and (5) to validate the long term stability of the modified LSCF cathode in commercially available cells under realistic operating conditions. We have systematically evaluated LSCF cathodes in symmetrical cells and anode supported cells under realistic conditions with different types of contaminants such as humidity, CO2, and Cr. Electrochemical models for the design of test cells and understanding of mechanisms have been developed for the exploration of fundamental properties of electrode materials. It is demonstrated that the activity and stability of LSCF cathodes can be degraded by the introduction of contaminants. The microstructural and compositional evolution of LSCF

  14. Performance of large-scale anode-supported solid oxide fuel cells with impregnated La{sub 0.6}Sr{sub 0.4}Co{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}}+Y{sub 2}O{sub 3} stabilized ZrO{sub 2} composite cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jing; Liang, Fengli; Yan, Dong; Pu, Jian; Chi, Bo; Jian, Li [School of Materials Science and Engineering, State Key Laboratory of Material Processing and Die and Mould Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Jiang, San Ping [School of Materials Science and Engineering, State Key Laboratory of Material Processing and Die and Mould Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798 (Singapore)

    2010-08-15

    Anode-supported planar solid oxide fuel cells (SOFCs) with an active area of 81 cm{sup 2} (9 cm x 9 cm) and nano-structured La{sub 0.6}Sr{sub 0.4}Co{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}} + Y{sub 2}O{sub 3} stabilized ZrO{sub 2} (LSCF + YSZ) composite cathodes are successfully fabricated by tape casting, screen printing, co-firing and solution impregnation, and tested using H{sub 2} fuel and air oxidant at various flow rates. Maximum power densities of 437 and 473 mW cm{sup -2} are achieved at 750 C by loading 0.6 and 1.3 mg cm{sup -2} of LSCF in the composite cathodes, respectively. The gas flow rates, particularly the air, have a significant effect on the cell performance. Cell performance degradation with time is also observed, which is considered to be associated with the growth and coalescence of the nanosized LSCF particles in the composite cathode. The use of the LSCF cathode in combination with YSZ electrolyte without a Gd-doped CeO{sub 2} (GDC) buffer layer is proved to be applicable in large cells, even though the thermal stability of the nanosized LSCF needs to be further improved. (author)

  15. Cathode materials review

    Energy Technology Data Exchange (ETDEWEB)

    Daniel, Claus, E-mail: danielc@ornl.gov; Mohanty, Debasish, E-mail: danielc@ornl.gov; Li, Jianlin, E-mail: danielc@ornl.gov; Wood, David L., E-mail: danielc@ornl.gov [Oak Ridge National Laboratory, 1 Bethel Valley Road, MS6472 Oak Ridge, TN 37831-6472 (United States)

    2014-06-16

    The electrochemical potential of cathode materials defines the positive side of the terminal voltage of a battery. Traditionally, cathode materials are the energy-limiting or voltage-limiting electrode. One of the first electrochemical batteries, the voltaic pile invented by Alessandro Volta in 1800 (Phil. Trans. Roy. Soc. 90, 403-431) had a copper-zinc galvanic element with a terminal voltage of 0.76 V. Since then, the research community has increased capacity and voltage for primary (nonrechargeable) batteries and round-trip efficiency for secondary (rechargeable) batteries. Successful secondary batteries have been the lead-acid with a lead oxide cathode and a terminal voltage of 2.1 V and later the NiCd with a nickel(III) oxide-hydroxide cathode and a 1.2 V terminal voltage. The relatively low voltage of those aqueous systems and the low round-trip efficiency due to activation energies in the conversion reactions limited their use. In 1976, Wittingham (J. Electrochem. Soc., 123, 315) and Besenhard (J. Power Sources 1(3), 267) finally enabled highly reversible redox reactions by intercalation of lithium ions instead of by chemical conversion. In 1980, Goodenough and Mizushima (Mater. Res. Bull. 15, 783-789) demonstrated a high-energy and high-power LiCoO{sub 2} cathode, allowing for an increase of terminal voltage far beyond 3 V. Over the past four decades, the international research community has further developed cathode materials of many varieties. Current state-of-the-art cathodes demonstrate voltages beyond any known electrolyte stability window, bringing electrolyte research once again to the forefront of battery research.

  16. Cathode materials review

    Science.gov (United States)

    Daniel, Claus; Mohanty, Debasish; Li, Jianlin; Wood, David L.

    2014-06-01

    The electrochemical potential of cathode materials defines the positive side of the terminal voltage of a battery. Traditionally, cathode materials are the energy-limiting or voltage-limiting electrode. One of the first electrochemical batteries, the voltaic pile invented by Alessandro Volta in 1800 (Phil. Trans. Roy. Soc. 90, 403-431) had a copper-zinc galvanic element with a terminal voltage of 0.76 V. Since then, the research community has increased capacity and voltage for primary (nonrechargeable) batteries and round-trip efficiency for secondary (rechargeable) batteries. Successful secondary batteries have been the lead-acid with a lead oxide cathode and a terminal voltage of 2.1 V and later the NiCd with a nickel(III) oxide-hydroxide cathode and a 1.2 V terminal voltage. The relatively low voltage of those aqueous systems and the low round-trip efficiency due to activation energies in the conversion reactions limited their use. In 1976, Wittingham (J. Electrochem. Soc., 123, 315) and Besenhard (J. Power Sources 1(3), 267) finally enabled highly reversible redox reactions by intercalation of lithium ions instead of by chemical conversion. In 1980, Goodenough and Mizushima (Mater. Res. Bull. 15, 783-789) demonstrated a high-energy and high-power LiCoO2 cathode, allowing for an increase of terminal voltage far beyond 3 V. Over the past four decades, the international research community has further developed cathode materials of many varieties. Current state-of-the-art cathodes demonstrate voltages beyond any known electrolyte stability window, bringing electrolyte research once again to the forefront of battery research.

  17. Highly-dispersed Ta-oxide catalysts prepared by electrodeposition in a non-aqueous plating bath for polymer electrolyte fuel cell cathodes

    KAUST Repository

    Seo, Jeongsuk

    2012-01-01

    The Ta-oxide cathode catalysts were prepared by electrodeposition in a non-aqueous solution. These catalysts showed excellent catalytic activity and have an onset potential of 0.92 V RHE for the oxygen reduction reaction (ORR). The highly-dispersed Ta species at the nanometer scale on the carbon black was an important contributor to the high activity. © 2012 The Royal Society of Chemistry.

  18. Direct ceramic inkjet printing of yttria-stabilized zirconia electrolyte layers for anode-supported solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Tomov, R.I.; Hopkins, S.C. [Applied Superconductivity and Cryoscience Group, Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB4 3QZ (United Kingdom); Krauz, M.; Kluczowski, J.R. [Institute of Power Engineering, Ceramic Department CEREL, 36-040 Boguchwala (Poland); Jewulski, J. [Institute of Power Engineering, Fuel Cells Department, 02-981 Warsaw (Poland); Glowacka, D.M. [Detector Physics Group, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE (United Kingdom); Glowacki, B.A. [Applied Superconductivity and Cryoscience Group, Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB4 3QZ (United Kingdom); Institute of Power Engineering, Fuel Cells Department, 02-981 Warsaw (Poland)

    2010-11-01

    Electromagnetic drop-on-demand direct ceramic inkjet printing (EM/DCIJP) was employed to fabricate dense yttria-stabilized zirconia (YSZ) electrolyte layers on a porous NiO-YSZ anode support from ceramic suspensions. Printing parameters including pressure, nozzle opening time and droplet overlapping were studied in order to optimize the surface quality of the YSZ coating. It was found that moderate overlapping and multiple coatings produce the desired membrane quality. A single fuel cell with a NiO-YSZ/YSZ ({proportional_to}6 {mu}m)/LSM + YSZ/LSM architecture was successfully prepared. The cell was tested using humidified hydrogen as the fuel and ambient air as the oxidant. The cell provided a power density of 170 mW cm{sup -2} at 800 C. Scanning electron microscopy (SEM) revealed a highly coherent dense YSZ electrolyte layer with no open porosity. These results suggest that the EM/DCIJP inkjet printing technique can be successfully implemented to fabricate electrolyte coatings for SOFC thinner than 10 {mu}m and comparable in quality to those fabricated by more conventional ceramic processing methods. (author)

  19. Synthesis and evaluation of Pt-alloys supported on MWCNTS as ethylene glycol-tolerant ORR cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Morales-Acosta, D.; Arriaga, L.G. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, Pedro Escobedo, Queretaro (Mexico); Alvarez-Contreras, L. [Centro de Investigacion en Materiales Avanzados S. C., Chihuahua, Chihuahua (Mexico); Fraire Luna, S.; Rodriguez Varela, F.J. [Cinvestav, Unidad Saltillo, Ramos Arizpe, Coahuila (Mexico)]. E-mail: javier.varela@cinvestav.edu.mx

    2009-09-15

    In this work, a Pt-Co/MWCNT alloy (atomic ratio 70:30) was synthesized and evaluated as oxygen reduction reaction (ORR) cathode for Direct Ethylene Glycol Fuel Cells (DEGFC) applications. The alloy showed good performance for the ORR in acid medium, while in the presence of 0.125M EG (C{sub 2}H{sub 6}O{sub 2}) the MWCNTs-supported electrocatalyst showed a very high selectivity for the cathodic reaction and a high degree of tolerance to the organic fuel, i.e., a very small shift in the onset potential for the ORR, Eonset, and no peak current densities associated to the oxidation of EG, a detrimental effect of organic fuels normally observed in the case of Pt-alone electrocatalysts. [Spanish] En este trabajo, se sintetizo y evaluo una aleacion Pt-Co/NTCMP (razon atomica 70/30) como catodo de reaccion de reduccion de oxigeno (RRO) para aplicaciones de celdas de combustible de glicol de etileno directo (CCGED). La aleacion mostro buen desempeno para la RRO en medio acido, en tanto que la presencia de 0.125M de GE (C{sub 2}H{sub 6}O{sub 2}) del electrocatalizador soportado por NTCMP mostro una muy alta selectividad para la reaccion catodica y un alto grado de tolerancia al combustible organico, es decir, un corrimiento muy pequeno del potencial de inicio para la RRO, Einicio, y no densidades de corriente asociadas a la oxidacion del GE, efecto perjudicial de los combustibles organicos que se observa en el caso del electrocatalizadores solo de Pt.

  20. Metal Oxide-Supported Platinum Overlayers as Proton-Exchange Membrane Fuel Cell Cathodes

    DEFF Research Database (Denmark)

    Tripkovic, Vladimir; Abild-Pedersen, Frank; Studt, Felix

    2012-01-01

    We investigated the activity and stability of n=(1, 2, 3) platinum layers supported on a number of rutile metal oxides (MO2; M=Ti, Sn, Ta, Nb, Hf and Zr). A suitable oxide support can alleviate the problem of carbon corrosion and platinum dissolution in Pt/C catalysts. Moreover, it can increase t...

  1. Lipon coatings for high voltage and high temperature Li-ion battery cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Dudney, Nancy J.; Liang, Chengdu; Nanda, Jagjit; Veith, Gabriel M.; Kim, Yoongu; Martha, Surendra Kumar

    2017-02-14

    A lithium ion battery includes an anode and a cathode. The cathode includes a lithium, manganese, nickel, and oxygen containing compound. An electrolyte is disposed between the anode and the cathode. A protective layer is deposited between the cathode and the electrolyte. The protective layer includes pure lithium phosphorus oxynitride and variations that include metal dopants such as Fe, Ti, Ni, V, Cr, Cu, and Co. A method for making a cathode and a method for operating a battery are also disclosed.

  2. Composition and growth behavior of the surface and electrolyte decomposition layer of/on a commercial lithium ion battery LixNi1/3Mn1/3Co1/3O2 cathode determined by sputter depth profile X-ray photoelectron spectroscopy.

    Science.gov (United States)

    Niehoff, Philip; Winter, Martin

    2013-12-23

    A detailed X-ray photoelectron spectroscopy (XPS) study of the surface and electrolyte decomposition layer of a LixNi1/3Mn1/3Co1/3O2 (NMC) cathode from commercial NMC/graphite cells by intense sputter depth profiling (SDP) using a polyatomic ion gun is provided. Cathodes of a cell after electrochemical formation and a cell at a state of initial capacity (SOIC) of 80%, which was reached after 2500 full cycles at 30 °C, are investigated.

  3. Break‐down of Losses in High Performing Metal‐Supported Solid Oxide Fuel Cells

    DEFF Research Database (Denmark)

    Kromp, A.; Nielsen, Jimmi; Blennow Tullmar, Peter;

    2013-01-01

    in the metal support, the electrochemical fuel oxidation at the anode and the oxygen reduction in the mixed ionic electronic conducting cathode. An additional process with a rather high relaxation frequency was attributed to the formation of insulating interlayers at the cathode/electrolyte‐interface. Based...... on these results, selective measures to improve performance and stability, such as (i) PVD‐deposited CGO buffer layer preventing solid state reaction between cathode and the zirconia‐based electrolyte, (ii) LSC‐CGO based in‐situ sintered cathodes and (iii) reduced corrosion of the metal support, were adopted...

  4. Oxidation of Carbon Supports at Fuel Cell Cathodes: Differential Electrochemical Mass Spectrometric Study

    Science.gov (United States)

    Li, Ming-fang; Tao, Qian; Liao, Ling-wen; Xu, Jie; Cai, Jun; Chen, Yan-xia

    2010-08-01

    The effects of O2 and the supported Pt nano-particles on the mechanisms and kinetics of the carbon support corrosion are investigated by monitoring the CO2 production using differential electrochemical mass spectrometry in a dual-thin layer flow cell. Carbon can be oxidized in different distinct potential regimes; O2 accelerates carbon oxidation, the rates of CO2 production from carbon oxidation in O2 saturated solution are two times of that in N2 saturated solution at the same potential; Pt can catalyze the carbon oxidation, with supported Pt nanoparticles, the overpotential for carbon oxidation is much smaller than that without loading in the carbon electrode. The mechanism for the enhanced carbon oxidation by Pt and O2 are discussed.

  5. Low platinum loading cathode modified with Cs3H2PMo10V2O40 for polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Renzi, M.; D'Angelo, G.; Marassi, R.; Nobili, F.

    2016-09-01

    The catalytic activity of commercial Pt nanoparticles mixed with mesoporous polyoxometalate Cs3H2PMo10V2O40 towards oxygen reduction reaction is evaluated. The polyoxometalate co-catalyst is prepared by titration of an aqueous solution of phosphovanadomolibdic acid. SEM micrography shows reduction particle size to less than 300 nm, while XRD confirms that the resulting salt maintains the Kegging structure. The composite catalyst is prepared by mixing the POM salt with Pt/C by sonication. RRDE studies show better kinetics for ORR with low Pt loading at the electrode surface. A MEA is assembled by using a Pt/POM-based cathode, in order to assess performance in a working fuel cell. Current vs. potential curves reveals comparable or better performances at 100%, 62% and 17% relative humidity for the POM-modified MEA with respect to a commercial MEA with higher Pt loading at the cathode. Electrochemical impedance spectroscopy (EIS) confirms better kinetics at low relative humidity. Finally, an accelerated stress test (AST) with square wave (SW) between 0.4 V and 0.8 V is performed to evaluate MEA stability for at least 100 h and make predictions about lifetime, showing that after initial losses the catalytic system can retain stable performance and good morphological stability.

  6. Macroelectrode voltammetry in toluene using a phosphonium-phosphate ionic liquid as the supporting electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Duffy, Noel W. [CSIRO Energy Technology, Clayton Laboratories, Vic. 3169 (Australia); Bond, Alan M. [School of Chemistry, Monash University, Clayton, Vic. 3800 (Australia)

    2006-05-15

    The ability of the ionic liquid trihexyl(tetradecyl)phosphonium tris(pentafluoroethyl)trifluorophosphate (aph4.cph12) to act as an ionic conductor in toluene has been investigated at platinum and glassy carbon macrodisc electrodes. Ionic liquid concentrations of 0.1-0.4M provide close to ideal conditions for transient dc cyclic and ac voltammetric techniques. A potential window of almost 5V is available at a glassy carbon electrode (the neat ionic liquid has a potential window of approximately 6V). In the presence of 0.4M ionic liquid, uncompensated solution resistances (in the range of 3-4k{omega}) are of the same order of magnitude as encountered in commonly used non-aqueous electrochemical solvents such as dichloromethane containing 0.1M Bu{sub 4}NPF{sub 6} as the electrolyte. Voltammetric data on ferrocene, the cobaltocenium cation, [Ru(bipy){sub 3}]{sup 2+} and C{sub 60} in toluene containing aph4.cph12 demonstrate the advantages of using this ionic liquid as an electrolyte in highly resistive media. (author)

  7. A dynamic human water and electrolyte balance model for verification and optimization of life support systems in space flight applications

    Science.gov (United States)

    Hager, P.; Czupalla, M.; Walter, U.

    2010-11-01

    In this paper we report on the development of a dynamic MATLAB SIMULINK® model for the water and electrolyte balance inside the human body. This model is part of an environmentally sensitive dynamic human model for the optimization and verification of environmental control and life support systems (ECLSS) in space flight applications. An ECLSS provides all vital supplies for supporting human life on board a spacecraft. As human space flight today focuses on medium- to long-term missions, the strategy in ECLSS is shifting to closed loop systems. For these systems the dynamic stability and function over long duration are essential. However, the only evaluation and rating methods for ECLSS up to now are either expensive trial and error breadboarding strategies or static and semi-dynamic simulations. In order to overcome this mismatch the Exploration Group at Technische Universität München (TUM) is developing a dynamic environmental simulation, the "Virtual Habitat" (V-HAB). The central element of this simulation is the dynamic and environmentally sensitive human model. The water subsystem simulation of the human model discussed in this paper is of vital importance for the efficiency of possible ECLSS optimizations, as an over- or under-scaled water subsystem would have an adverse effect on the overall mass budget. On the other hand water has a pivotal role in the human organism. Water accounts for about 60% of the total body mass and is educt and product of numerous metabolic reactions. It is a transport medium for solutes and, due to its high evaporation enthalpy, provides the most potent medium for heat load dissipation. In a system engineering approach the human water balance was worked out by simulating the human body's subsystems and their interactions. The body fluids were assumed to reside in three compartments: blood plasma, interstitial fluid and intracellular fluid. In addition, the active and passive transport of water and solutes between those

  8. Development of high-performance cathode catalyst of polypyrrole modified carbon supported CoOOH for direct borohydride fuel cell

    Science.gov (United States)

    He, Yan; Zhu, Cai; Chen, Kaijian; Wang, Juan; Qin, Haiying; Liu, Jiabin; Yan, Shuai; Yang, Ke; Li, Aiguo

    2017-01-01

    Polypyrrole modified carbon supported CoOOH electrocatalyst (CoOOH-PPy-C) is prepared by impregnation-chemical method, and the catalytic properties for the oxygen reduction reaction (ORR) in alkaline media are investigated. The X-ray diffraction and transmission electron microscopy results confirm the presence of the expected CoOOH. The electrochemical tests show that the CoOOH-PPy-C catalyst exhibits good electrocatalytic activity towards ORR. The direct borohydride fuel cell using CoOOH-PPy-C as the cathode catalyst demonstrates a good stability performance. There is only 4% decrease of the cell voltage after 80-h operation. The ORR occurs an average 4-electron transfer pathway on the CoOOH-PPy-C catalyst. The good catalytic activity towards ORR benefits from the Cosbnd N bond, which is identified by X-ray photoelectron spectroscopy test. X-ray absorption fine structure experiments further show that two nearest O atoms are substituted by two N atoms bonding to Co ion at a distance of 1.64 Å. The CoOOH-PPy-C exhibits better electrochemical properties than the Co(OH)2 counterpart even though the valence state of Co ion is +3 in CoOOH-PPy-C. Those results indicate that the bonding of Co ion with N atoms should be a key issue regardless the valence of Co ion.

  9. Development status of solid polymer electrolyte water electrolysis for manned spacecraft life support systems

    Science.gov (United States)

    Nuttall, L. J.; Titterington, W. A.

    1974-01-01

    Details of the design and system verification test results are presented for a six-man-rated oxygen generation system. The system configuration incorporates components and instrumentation for computer-controlled operation with automatic start-up/shutdown sequencing, fault detection and isolation, and with self-contained sensors and controls for automatic safe emergency shutdown. All fluid and electrical components, sensors, and electronic controls are designed to be easily maintainable under zero-gravity conditions. On-board component spares are utilized in the system concept to sustain long-term operation (six months minimum) in a manned spacecraft application. The system is centered on a 27-cell solid polymer electrolyte water electrolysis module which, combined with the associated system components and controls, forms a total system envelope 40 in. high, 40 in. wide, and 30 in. deep.

  10. Applications of nano-composite materials for improving the performance of anode-supported electrolytes of SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong-Jin; Moon, Hwan; Park, Hae-Gu; Yoon, Dae Il; Hyun, Sang-Hoon [School of Advanced Materials Science and Engineering, Yonsei Univ., Seoul 120-749 (Korea)

    2010-01-15

    In order to improve the performance of the anode-supported electrolyte of solid oxide fuel cells (SOFCs), the anode electrode is modified by inserting an anode functional layer of nano-composite powders between a Ni-YSZ electrode and YSZ electrolyte. The NiO-YSZ nano-composite powders are fabricated by coating nano-sized Ni and YSZ particles on the YSZ core particle by the Pechini process. The reduction of the polarization resistance of a single cell that is applied to the anode functional layer is attributed to the increasing reaction of three-phase boundaries (TPBs) within the layer and the micro-structured uniformity in the electrode. Two methods were used, namely tape-casting/dip-coating and tape-casting/co-firing, for studying the performance. It can be concluded that the cell with an anode functional layer thickness (15-20 {mu}m) and a microstructure of NiO-YSZ nano-composite materials which was fabricated by the tape-casting/dip-coating method improved the output power (to 1.3 W cm{sup -2}) at 800 C using hydrogen as fuel and air as an oxidant. (author)

  11. Photoassisted formation of Cu(x)S-based cathodes for CdS-sensitized solar cells with S(2-)/S(x)(2-) electrolyte.

    Science.gov (United States)

    Kozytskiy, Andriy; Stroyuk, Oleksandr; Skoryk, Mykola; Kuchmiy, Stepan

    2015-05-01

    The sulfidation of copper nanoparticles deposited onto ZnO surface by the photocatalytic reduction of Cu(II) results in the formation of ZnO/CuxS films that can be used as efficient counter electrodes in solar cells based on sulfide/polysulfide electrolytes. The films are formed by the spherical copper sulfide nano/micro-aggregates of tabulate CuxS nanoparticles with x = 1.3-1.4. A model cell with a FTO/ZnO/CdS photoanode produced by SILAR and FTO/ZnO/CuxS films as counter-electrode showed a light conversion efficiency, η = 1.73%, which is 25% higher than a similar cell where copper sulfide was deposited onto ZnO in "dark" conditions. Varying the conditions of the photocatalytic deposition of the starting copper nanoparticles slightly affects the electrocatalytic properties of the final FTO/ZnO/CuxS heterostructures.

  12. BaZr{sub 0.1}Ce{sub 0.7}Y{sub 0.1}Yb{sub 0.1}O{sub 3-{delta}} electrolyte-based solid oxide fuel cells with cobalt-free PrBaFe{sub 2}O{sub 5+{delta}} layered perovskite cathode

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Hanping; Xue, Xingjian [Department of Mechanical Engineering, University of South Carolina, Columbia, SC 29208 (United States)

    2010-10-15

    A new anode-supported SOFC material system Ni-BZCYYb vertical stroke BZCYYb vertical stroke PBFO is investigated, in which a cobalt-free layered perovskite oxide, PrBaFe{sub 2}O{sub 5+{delta}} (PBFO), is synthesized and employed as a novel cathode while the synthesized BZCYYb is used as an electrolyte. The cell is fabricated by a simple dry-pressing/co-sintering process. The cell is tested and characterized under intermediate temperature range from 600 to 700 C with humified H{sub 2} ({proportional_to}3% H{sub 2}O) as fuel, ambient air as oxidant. The results show that the open-circuit potential of 1.006 V and maximal power density of 452 mW cm{sup -2} are achieved at 700 C. The polarization resistance of the electrodes is 0.18 {omega} cm{sup 2} at 700 C. Compared to BaZr{sub 0.1}Ce{sub 0.7}Y{sub 0.1}O{sub 3-{delta}}, the conductivity of co-doped barium zirconate-cerate BZCYYb is significantly improved. The ohmic resistance of single cell is 0.37 {omega} cm{sup 2} at 700 C. The results indicate that the developed Ni-BZCYYb vertical stroke BZCYYb vertical stroke PBFO cell is a promising functional material system for SOFCs. (author)

  13. La0.8Sr0.2Fe0.8Cu0.2O3-δ as “cobalt-free” cathode for La0.8Sr0.2Ga0.8Mg0.2O3-δ electrolyte

    Science.gov (United States)

    Zurlo, Francesca; Di Bartolomeo, Elisabetta; D'Epifanio, Alessandra; Felice, Valeria; Natali Sora, Isabella; Tortora, Luca; Licoccia, Silvia

    2014-12-01

    A "cobalt-free" cathode material with stoichiometric composition La0.8Sr0.2Fe0.8Cu0.2O3-δ (LSFCu) was specifically developed for use with La0.8Sr0.2Ga0.8Mg0.2O3-δ (LSGM) electrolyte in intermediate temperature solid oxide fuel cell (IT-SOFC) systems. The chemical stability of LSFCu in contact with LSGM electrolyte was investigated by structural and morphological analysis. The electrochemical properties of LSFCu dense pellets were investigated in the temperature range 600-750 °C by electrochemical impedance spectroscopy (EIS). LSFCu|LSGM|LSFCu symmetrical cells were prepared and area specific resistance (ASR) values, directly depending on the rate limiting step of the oxygen reduction reaction, were evaluated. Fuel cells were prepared using LSFCu as cathode material on a LSGM pellet and electrochemical tests were performed in the 700-800 °C temperature range and compared to similar fuel cells prepared by using commercial La0.6Sr0.4Fe0.8Co0.2O3-δ (LSFCo) as a cathode. The maximum current density and power density recorded for LSFCu and LSFCo were similar. This fact demonstrates that Cu can be used as Co substitute in perovskite cathode materials.

  14. Mutual diffusion occurring at the interface between La₀.₆Sr₀.₄Co₀.₈Fe₀.₂O₃ cathode and Gd-doped ceria electrolyte during IT-SOFC cell preparation.

    Science.gov (United States)

    Li, Zhi-Peng; Toshiyuki, Mori; Auchterlonie, Graeme John; Zou, Jin; John, Drennan

    2011-07-01

    The microstructure and local chemistry of the interface between the screen-printed La(0.6)Sr(0.4)Co(0.8)Fe(0.2)O(3) (LSCF) thin film cathode and Gd-doped ceria (GDC) electrolyte substrate have been investigated. Elemental distribution analyses, by energy-dispersive X-ray spectroscopy operated in scanning transmission electron microscopy (STEM) mode, illustrate that all constituent elements in GDC and LSCF mutually diffuse across the LSCF/GDC interface, with equal diffusion length. This leads to the formation of mutual diffusion zones at the LSCF/GDC interfaces, with the resultant mixture of diffusing ions being associated with specific valence state changes, as verified by STEM electron energy loss spectroscopy analyses. Moreover, this mutual diffusion can result in microstructural changes, where superstructure formation is accompanied by enhancement of oxygen vacancy ordering at this region. Such mutual diffusion and associated microstructure evolution is considered to be detrimental to fuel cell efficiency and should be suppressed by lowering cell fabrication temperatures.

  15. Electrodeposition of polymer electrolyte in nanostructured electrodes for enhanced electrochemical performance of thin-film Li-ion microbatteries

    Science.gov (United States)

    Salian, Girish D.; Lebouin, Chrystelle; Demoulin, A.; Lepihin, M. S.; Maria, S.; Galeyeva, A. K.; Kurbatov, A. P.; Djenizian, Thierry

    2017-02-01

    We report that electrodeposition of polymer electrolyte in nanostructured electrodes has a strong influence on the electrochemical properties of thin-film Li-ion microbatteries. Electropolymerization of PMMA-PEG (polymethyl methacrylate-polyethylene glycol) was carried out on both the anode (self-supported titania nanotubes) and the cathode (porous LiNi0.5Mn1.5O4) by cyclic voltammetry and the resulting electrode-electrolyte interface was examined by scanning electron microscopy. The electrochemical characterizations performed by galvanostatic experiments reveal that the capacity values obtained at different C-rates are doubled when the electrodes are completely filled by the polymer electrolyte.

  16. A three-dimensional pore-scale model of the cathode electrode in polymer-electrolyte membrane fuel cell by lattice Boltzmann method

    Science.gov (United States)

    Molaeimanesh, G. R.; Akbari, M. H.

    2014-07-01

    High power density, low operation temperature, high efficiency and low emissions have granted proton exchange membrane (PEM) fuel cells the most promising future among all types of fuel cells. The porous electrodes of PEM fuel cells have a complicated, non-homogeneous, anisotropic microstructure. Therefore, pore-scale modeling techniques such as lattice Boltzmann method, which can capture non-homogeneous and anisotropic microstructures, have recently gained a great attention. In the present study, a three-dimensional lattice Boltzmann model of a PEM fuel cell cathode electrode is proposed in which electrochemical reaction on the catalyst layer and microstructure of GDL are taken into account. The model enables us to simulate single-phase, multi-species reactive flow in a heterogeneous, anisotropic gas diffusion layer through an active approach. To show the capability of the proposed model, reactive flow in three reconstructed GDLs with different anisotropic characteristics is simulated to investigate the effects of GDL microstructure on species and current density distributions. The results demonstrate that when carbon fibers are more likely oriented normal to the catalyst layer, species density distribution is thicker and more disturbed. Current density also experiences a larger variation on the catalyst layer in such a case.

  17. Influence of support electrolytic in the electrodeposition of Cusbnd Gasbnd Se thin films

    Science.gov (United States)

    Fernandez, A. M.; Turner, J. A.; Lara-Lara, B.; Deutsch, T. G.

    2017-01-01

    CuGaSe2 is an important thin film electronic material that possesses several attributes that make it appealing for solar energy conversion. Due to its properties it can be incorporated in to various devices, among the greatest highlights are photovoltaic cells, as well as its potential use as photocathodes for hydrogen production, via the photoelectrolysis. There are several methods of its preparation, most notably electrodeposition that has the potential for large areas and high volumes. Electrodeposition of ternary and/or quaternary semiconductors generally proceeds via the formation of a binary, which is subsequently reacted to form the ternary compound. Several conditions must be controlled to form binary compounds that include the use of complexing agents, buffers, temperature, etc. In this paper, we discuss the effect of anion composition in the electrolytic bath and the type of lithium salts, in order to manipulate the atomic concentration of CuGaSe2 during the electrodeposition of thin films, yielding copper-rich, gallium-rich or stoichiometric thin films. We also present the results of a study on the morphology and structure obtained using two types of substrates both before and after performing a heat treatment.

  18. Influence of support electrolytic in the electrodeposition of CuGaSe thin films

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, A. M.; Turner, J. A.; Lara-Lara, B.; Deutsch, T. G.

    2017-01-01

    CuGaSe2 is an important thin film electronic material that possesses several attributes that make it appealing for solar energy conversion. Due to its properties it can be incorporated in to various devices, among the greatest highlights are photovoltaic cells, as well as its potential use as photocathodes for hydrogen production, via the photoelectrolysis. There are several methods of its preparation, most notably electrodeposition that has the potential for large areas and high volumes. Electrodeposition of ternary and/or quaternary semiconductors generally proceeds via the formation of a binary, which is subsequently reacted to form the ternary compound. Several conditions must be controlled to form binary compounds that include the use of complexing agents, buffers, temperature, etc. In this paper, we discuss the effect of anion composition in the electrolytic bath and the type of lithium salts, in order to manipulate the atomic concentration of CuGaSe2 during the electrodeposition of thin films, yielding copper-rich, gallium-rich or stoichiometric thin films. We also present the results of a study on the morphology and structure obtained using two types of substrates both before and after performing a heat treatment.

  19. Cathodic arcs

    OpenAIRE

    Anders, Andre

    2003-01-01

    Cathodic arc plasma deposition has become the technology of choice for hard, wear and corrosion resistant coatings for a variety of applications. The history, basic physics of cathodic arc operation, the infamous macroparticle problem and common filter solutions, and emerging high-tech applications are briefly reviewed. Cathodic arc plasmas stand out due to their high degree of ionization, with important consequences for film nucleation, growth, and efficient utilization of substrate bia...

  20. Preparation and Endurance of Electrolyte-Supported Solid Oxide Fuel Cell%电解质支持型固体氧化物燃料电池的制备及其工作稳定性

    Institute of Scientific and Technical Information of China (English)

    刘润茹; 王德军; 冷静

    2014-01-01

    利用固相反应法制备固体氧化物燃料电池(SOFC)的复合阳极材料 NiO-ScSZ 和复合阴极材料(La0.8 Sr0.2)0.98 MnO3(LSM),并对组装的电解质支持型单电池 NiO-ScSZ-LSM进行I-V性能测试,其输出电压每0.2 A为0.9 V.在外加恒定电流密度(0.2 A/cm2)的条件下,利用电化学测试仪测试该电池的总电压为每1000 h衰减0.02 V.电流遮断法解析表明,该单电池电压衰减主要为阴极过电压所致.%Cermet anode material NiO-ScSZ and cathode material (La0.8 Sr0.2 )0.98 MnO3 (LSM)were prepared via solid state reaction method. The performance electrolyte-supported single cell of NiO-ScSZ-LSM exibited an output voltage of 0.9 V at 0.2 A described by current-voltage characterized curve.The investigation on the endurance of the single cell indicates that the whole voltage decay is 0.02 V per 1 000 h (at a current density of 0.2 A/cm2 )by electro-chemical measurement.The main resource of it comes from cathodic over-voltage by galvanic current interruption method.

  1. Preparation of catalyst for a polymer electrolyte fuel cell using a novel spherical carbon support

    Energy Technology Data Exchange (ETDEWEB)

    Eguchi, Mika; Okubo, Atsuhiko; Kobayashi, Yoshio [Department of Biomolecular Functional Engineering, Faculty of Engineering, Ibaraki University, 4-12-1, Nakanarusawa, Hitachi, Ibaraki 316-8511 (Japan); Yamamoto, Shun [Material and Biological Sciences, Graduate School of Science and Engineering, Faculty of Engineering, Ibaraki University, 4-12-1, Nakanarusawa, Hitachi, Ibaraki 316-8511 (Japan); Kikuchi, Mayuko; Nishitani-Gamo, Mikka [Department of Applied Chemistry, Faculty of Engineering, Toyo University, 2100 Kujirai, Kawagoe, Saitama 350-8585 (Japan); Uno, Katsuhiro [Department of Media and Telecommunications Engineering, Faculty of Engineering, Ibaraki University, 4-12-1, Nakanarusawa, Hitachi, Ibaraki 316-8511 (Japan); Ando, Toshihiro [National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

    2010-09-15

    In this study, the support Pt catalyst was supported by a novel spherical carbon using a convenient technique. Two different preparation methods utilizing a nanocolloidal solution method without heat treatment were developed (methods 1 and 2). The scanning electron microscope (SEM) and transmission electron microscope (TEM) observations showed that the Pt nanoparticles (particle size) were supported, with higher dispersion being achieved with method 2 than method 1. The peak of the Pt metal was confirmed from the X-ray diffraction (XRD) measurement. Based on the inductively coupled plasma mass spectrometry (ICP-MS) measurements, Pt loading was 19.5 wt.% in method 1 and approximately 50 wt.% in method 2. The Pt specific surface area of the Pt/novel spherical carbon catalyst calculated from the cyclic voltammetry (CV) measurement result was larger than that of the commercially available Pt/Ketjen catalyst. These results indicated that the Pt nanoparticles were supported in high dispersion without heat treatment using novel spherical carbon as a carbon support. (author)

  2. Pt supported on nanosized oxides for electrocatalyst used in polymer electrolyte fuel cells

    DEFF Research Database (Denmark)

    Banu, N.; Serban, E. C.; Marinescu, A.

    2011-01-01

    Even though Pt is a standard catalyst for fuel cells, new advanced materials with low activation energy and high specific surface area are required. Researches proved that conducting oxides are the emerging candidates as support for Pt catalysts targeting replacement of nanocarbons. This paper...

  3. In Situ Analysis of the Li-O2 Battery with Thermally Reduced Graphene Oxide Cathode: Influence of Water Addition

    DEFF Research Database (Denmark)

    Storm, Mie Møller; Christensen, Mathias Kjærgård; Younesi, Reza

    2016-01-01

    The Li-O2 battery technology holds the promise to deliver a battery with significantly increased specific energy compared to today's Li-ion batteries. As a cathode support material, reduced graphene oxide has received increasing attention in the Li-O2 battery community due to the possibility......-of-the cathode and not only on addition of water to the electrolyte as demonstrated by the solution-based mechanism In situ synchrotron X-ray diffraction experiment using a new design of a capillary-based Li-O2 cell with a thermally reduced graphene oxide cathode shows formation of LiOH along with Li2O2....... of increased discharge capacity, increased battery cyclability, and decreased, charging, overpotential. In this. article we investigate the effect of water on a thermally, redircedigraphene, oxide cathode in a Li-O2 battery. Differential electrochemical mass spectrciscnieveals a, decreased electron count...

  4. Electrolyte materials - Issues and challenges

    Energy Technology Data Exchange (ETDEWEB)

    Balbuena, Perla B. [Department of Chemical Engineering, and Department of Materials Science and Engineering, Texas A and M University, College Station, Texas, 77843 (United States)

    2014-06-16

    Electrolytes are vital components of an electrochemical energy storage device. They are usually composed of a solvent or mixture of solvents and a salt or a mixture of salts which provide the appropriate environment for ionic conduction. One of the main issues associated with the selection of a proper electrolyte is that its electronic properties have to be such that allow a wide electrochemical window - defined as the voltage range in which the electrolyte is not oxidized or reduced - suitable to the battery operating voltage. In addition, electrolytes must have high ionic conductivity and negligible electronic conductivity, be chemically stable with respect to the other battery components, have low flammability, and low cost. Weak stability of the electrolyte against oxidation or reduction leads to the formation of a solid-electrolyte interphase (SEI) layer at the surface of the cathode and anode respectively. Depending on the materials of the electrolyte and those of the electrode, the SEI layer may be composed by combinations of organic and inorganic species, and it may exert a passivating role. In this paper we discuss the current status of knowledge about electrolyte materials, including non-aqueous liquids, ionic liquids, solid ceramic and polymer electrolytes. We also review the basic knowledge about the SEI layer formation, and challenges for a rational design of stable electrolytes.

  5. Effects of background electrolytes and ionic strength on enrichment of Cd(II) ions with magnetic graphene oxide-supported sulfanilic acid.

    Science.gov (United States)

    Hu, Xin-jiang; Liu, Yun-guo; Zeng, Guang-ming; You, Shao-hong; Wang, Hui; Hu, Xi; Guo, Yi-ming; Tan, Xiao-fei; Guo, Fang-ying

    2014-12-01

    To elucidate the influence mechanisms of background electrolytes and ionic strength on Cd(II) removal, the adsorption of Cd(II) onto magnetic graphene oxide-supported sulfanilic acid (MGO-SA) in aqueous solutions containing different types and concentrations of background electrolytes was studied. The results indicate that Cd(II) adsorption was strongly dependent on pH and could be strongly affected by background electrolytes and ionic strength. The Cd(II) removal was decreased with the presence of background electrolyte cations (Na(+), K(+), Ca(2+), Mg(2+), Mn(2+), Zn(2+), and Ni(2+)), and the divalent cations exerted more obvious influences on the Cd(II) uptake than the monovalent cations at pH 6. Both Cl(-) and NO3(-) had negative effects on Cd(II) adsorption because they can form water-soluble metal-anion complexes with Cd(II) ions. The presence of 0.01molL(-1) Na3PO4 reduced the removal percentage of Cd(II) at pH5. The Cd(II) adsorption was sensitive to changes in the concentration of NaCl, NaNO3, NaClO4, and Na3PO4. Besides, the adsorption isotherm of Cd(II) onto MGO-SA could be well described by the Freundlich model and was also influenced by the type of background electrolyte ions and the ionic strength.

  6. Solid polymer electrolyte water electrolysis preprototype subsystem. [oxygen production for life support systems on space stations

    Science.gov (United States)

    1979-01-01

    Hardware and controls developed for an electrolysis demonstration unit for use with the life sciences payload program and in NASA's regenerative life support evaluation program are described. Components discussed include: the electrolysis module; power conditioner; phase separator-pump and hydrogen differential regulator; pressure regulation of O2, He, and N2; air-cooled heat exchanger; water accumulator; fluid flow sight gage assembly; catalytic O2/H2 sensor; gas flow sensors; low voltage power supply; 100 Amp DC contactor assembly; and the water purifier design.

  7. Nanoporous silver cathode surface treated by atomic layer deposition of CeO(x) for low-temperature solid oxide fuel cells.

    Science.gov (United States)

    Neoh, Ke Chean; Han, Gwon Deok; Kim, Manjin; Kim, Jun Woo; Choi, Hyung Jong; Park, Suk Won; Shim, Joon Hyung

    2016-05-06

    We evaluated the performance of solid oxide fuel cells (SOFCs) with a 50 nm thin silver (Ag) cathode surface treated with cerium oxide (CeO(x)) by atomic layer deposition (ALD). The performances of bare and ALD-treated Ag cathodes were evaluated on gadolinia-doped ceria (GDC) electrolyte supporting cells with a platinum (Pt) anode over 300 °C-450 °C. Our work confirms that ALD CeO(x) treatment enhances cathodic performance and thermal stability of the Ag cathode. The performance difference between cells using a Ag cathode optimally treated with an ALD CeO(x) surface and a reference Pt cathode is about 50% at 450 °C in terms of fuel cell power output in our experiment. The bare Ag cathode completely agglomerated into islands during fuel cell operation at 450 °C, while the ALD CeO(x) treatment effectively protects the porosity of the cathode. We also discuss the long-term stability of ALD CeO(x)-treated Ag cathodes related to the microstructure of the layers.

  8. 81.114- University Reactor Infrastructure and Education Support / Prompt Gamma-ray Activation Analysis of Lithioum Ion Battery Cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Manthiram, Arumugam; Landsberger, S.

    2006-11-11

    This project focuses on the use of the Prompt Gamma-ray Activation Analysis (PGAA) technique available at the Nuclear Engineering Teaching Laboratory of the University of Texas at Austin to precisely determine the hydrogen (proton) contents in layered oxide cathode samples obtained by chemical lithium extraction in order to obtain a better understanding of the factors limiting the practical capacities and overall performance of lithium ion battery cathodes. The project takes careful precautionary experimental measures to avoid proton contamination both from solvents used in chemical delithiation and from ambient moisture. The results obtained from PGAA are complemented by the data obtained from other techniques such as thermogravimetric analysis, redox titration, atomic absorption spectroscopy, X-ray diffraction, and mass spectroscopic analysis of the evolved gas on heating. The research results broaden our understanding of the structure-property-performance relationships of lithium ion battery cathodes and could aid the design and development of new better performing lithium ion batteries for consumer (portable and electric vehicles), military, and space applications.

  9. Application of Co-naphthalocyanine (CoNPc) as alternative cathode catalyst and support structure for microbial fuel cells.

    Science.gov (United States)

    Kim, Jung Rae; Kim, Jy-Yeon; Han, Sang-Beom; Park, Kyung-Won; Saratale, G D; Oh, Sang-Eun

    2011-01-01

    Co-naphthalocyanine (CoNPc) was prepared by heat treatment for cathode catalysts to be used in microbial fuel cells (MFCs). Four different catalysts (Carbon black, NPc/C, CoNPc/C, Pt/C) were compared and characterized using XPS, EDAX and TEM. The electrochemical characteristics of oxygen reduction reaction (ORR) were compared by cyclic voltammetry (CV) and linear sweep voltammetry (LSV). The Co-macrocyclic complex improves the catalyst dispersion and oxygen reduction reaction of CoNPc/C. The maximum power of CoNPc/C was 64.7 mW/m(2) at 0.25 mA as compared with 81.3 mW/m(2) of Pt/C, 29.7 mW/m(2) of NPc/C and 9.3 mW/m(2) of carbon black when the cathodes were implemented in H-type MFCs. The steady state cell, cathode and anode potential of MFC with using CoNPc/C were comparable to those of Pt/C.

  10. X-ray absorption spectroscopy characterization of Zn underpotential deposition on Au(1 1 1) from phosphate supporting electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jonathan R.I., E-mail: lee204@llnl.go [Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW (United Kingdom); Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); O' Malley, Rachel L.; O' Connell, Timothy J. [Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW (United Kingdom); Vollmer, Antje [Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW (United Kingdom); Helmholtz Zentrum Berlin f. Materialien und Energie, BESSY II, Albert-Einstein-Str. 15, 12489 Berlin (Germany); Rayment, Trevor, E-mail: trevor.rayment@diamond.ac.u [Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW (United Kingdom); Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom)

    2010-12-01

    Zn K-edge X-ray absorption spectroscopy (XAS) has been used to investigate the structure of Zn monolayers prepared on Au(1 1 1) electrodes via underpotential deposition (UPD) from phosphate supporting electrolyte. Theoretical modeling of the XAS data indicates that the Zn adatoms adopt a commensurate ({radical}3 x {radical}3)R30{sup o} ({theta}{sub sc} = 0.33) adlayer structure and reside within the 3-fold hollow sites of the Au(1 1 1) surface. Meanwhile, phosphate counter-ions co-adsorb on the UPD adlayer and bridge between the Zn adatoms in a ({radical}3 x {radical}3)R30{sup o} ({theta}{sub sc} = 0.33) configuration, with each phosphorous atom residing above a vacant 3-fold hollow site of the Au(1 1 1). Significantly, this surface structure is invariant between the electrochemical potential for UPD adlayer formation and the onset of bulk Zn electrodeposition. Analysis of the Zn K-edge absorption onset also presents the possibility that the Zn adatoms do not fully discharge during the process of UPD, which had been proposed in prior voltammetric studies of the phosphate/Zn(UPD)/Au(1 1 1) system.

  11. X-ray Absorption Spectroscopy Characterization of Zn Underpotential Deposition on Au(111) from Phosphate Supporting Electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J R; O' Malley, R L; O' Connell, T J; Vollmer, A; Rayment, T

    2009-12-11

    Zn K-edge X-ray absorption spectroscopy (XAS) has been used to investigate the structure of Zn monolayers prepared on Au(111) electrodes via underpotential deposition (UPD) from phosphate supporting electrolyte. Theoretical modeling of the XAS data indicates that the Zn adatoms adopt a commensurate ({radical}3x{radical}3)R30{sup o} ({mu}{sub sc} = 0.33) adlayer structure and reside within the 3-fold hollow sites of the Au(111) surface. Meanwhile, phosphate counter-ions co-adsorb on the UPD adlayer and bridge between the Zn adatoms in a ({radical}3x{radical}3)R30{sup o} ({mu}{sub sc} = 0.33) configuration, with each phosphorous atom residing above a vacant 3-fold hollow site of the Au(111). Significantly, this surface structure is invariant between the electrochemical potential for UPD adlayer formation and the onset of bulk Zn electrodeposition. Analysis of the Zn K-edge absorption onset also presents the possibility that the Zn adatoms do not fully discharge during the process of UPD, which had been proposed in prior voltammetric studies of the phosphate/Zn(UPD)/Au(111) system.

  12. High temperature electrolyte supported Ni-GDC/YSZ/LSM SOFC operation on two-stage Viking gasifier product gas

    Science.gov (United States)

    Hofmann, Ph.; Schweiger, A.; Fryda, L.; Panopoulos, K. D.; Hohenwarter, U.; Bentzen, J. D.; Ouweltjes, J. P.; Ahrenfeldt, J.; Henriksen, U.; Kakaras, E.

    This paper presents the results from a 150 h test of a commercial high temperature single planar solid oxide fuel cell (SOFC) operating on wood gas from the Viking two-stage fixed-bed downdraft gasifier, which produces an almost tar-free gas, that was further cleaned for particulates, sulphur and tar traces. The chosen SOFC was electrolyte supported with a nickel/gadolinium-doped cerium oxide (Ni-GDC) anode, known for its carbon deposition resistance. Through humidification the steam to carbon ratio (S/C) was adjusted to 0.5, which results in a thermodynamically carbon free condition at the SOFC operating temperature T = 850 °C. The cell operated with a fuel utilisation factor (U f) around 30% and a current density of 260 mA cm -2 resulting in an average power density of 207 mW cm -2. Throughout the duration of the test, only a minor cell overpotential increase of 10 mV was observed. Nevertheless, the V- j (voltage-current density) curves on H 2/N 2 before and after the wood gas test proved identical. Extensive SEM/EDS examination of the cell's anode showed that there was neither carbon deposition nor significant shifts in the anode microstructure or contamination when compared to an identical cell tested on H 2/N 2 only.

  13. A Comparative Study of Electrolyte Flow and Slime Particle Transport in a Newly Designed Copper Electrolytic Cell and a Laboratory-Scale Conventional Electrolytic Cell

    Science.gov (United States)

    Zeng, Weizhi; Wang, Shijie; Free, Michael L.

    2016-08-01

    An innovative copper electrolytic cell was designed with its inlet at the cell top and its outlet near the cell bottom, in opposite to conventional electrolytic cells. It was modeled in COMSOL Multiphysics to simulate copper electrorefining process. Unlike conventional electrorefining cells, downward electrolyte flows are more dominant in the fluid flow field in this cell, which leads to faster settlement of slime particles and less contamination to the cathode. Copper concentration profiles, electrolyte flow velocity field, slime particle movements, and slime particle distributions were obtained as simulation results, which were compared with those in a laboratory-scale conventional electrolytic cell. Advantages of the newly designed electrolytic cell were found: copper ions are distributed more uniformly in the cell with a thinner diffusion layer near the cathode; stronger convection exists in the inter-electrode domain with dominant downward flows; and slime particles have larger possibilities to settle down and are less likely to reach the cathode.

  14. Highly porous PEM fuel cell cathodes based on low density carbon aerogels as Pt-support: Experimental study of the mass-transport losses

    Science.gov (United States)

    Marie, Julien; Chenitz, Regis; Chatenet, Marian; Berthon-Fabry, Sandrine; Cornet, Nathalie; Achard, Patrick

    Carbon aerogels exhibiting high porous volumes and high surface areas, differentiated by their pore-size distributions were used as Pt-supports in the cathode catalytic layer of H 2/air-fed PEM fuel cell. The cathodes were tested as 50 cm 2 membrane electrode assemblies (MEAs). The porous structure of the synthesized catalytic layers was impacted by the nanostructure of the Pt-doped carbon aerogels (Pt/CAs). In this paper thus we present an experimental study aiming at establishing links between the porous structure of the cathode catalytic layers and the MEAs performances. For that purpose, the polarization curves of the MEAs were decomposed in 3 contributions: the kinetic loss, the ohmic loss and the mass-transport loss. We showed that the MEAs made with the different carbon aerogels had similar kinetic activities (low current density performance) but very different mass-transport voltage losses. It was found that the higher the pore-size of the initial carbon aerogel, the higher the mass-transport voltage losses. Supported by our porosimetry (N 2-adsorption and Hg-porosimetry) measurement, we interpret this apparent contradiction as the consequence of the more important Nafion penetration into the carbon aeorogel with larger pore-size. Indeed, the catalytic layers made from the larger pore-size carbon aerogel had lower porosities. We thus show in this work that carbon aerogels are materials with tailored nanostructured structure which can be used as model materials for experimentally testing the optimization of the PEM fuel cell catalytic layers.

  15. Electrochemistry Study on PVC-LiClO4 Polymer Electrolyte Supported by Bengkulu Natural Bentonite for Lithium Battery

    Directory of Open Access Journals (Sweden)

    Ghufira

    2012-04-01

    Full Text Available In this research bentonite was used as filler to produce polymer electrolyte (PVCLiClO4. Some weight variation of bentonite have been made by addition, such as 0% wt/wt; 5% wt/wt ; 10% wt/wt ; 15% wt/wt ; 20% wt/wt ; and 25% wt/wt of bentonite to the mixture of 0,5 gramof PVC and 0,125 gram of LiClO4. Ionic conductivity of polymer electrolyte was tested using impedance spectroscopy. The result of the research was showed that a mixture of PVCBentonite(10% wt/wt-LiClO4 gives the highest ionic conductivity (4,86 x 10-3 S.Cm-1. This result indicated that the presence of natural bentonite can be used as a filler in the current composite polymer electrolyte and can increase the ionic conductivity of the polymer electrolyte.

  16. Cathodic arcs

    Energy Technology Data Exchange (ETDEWEB)

    Anders, Andre

    2003-10-29

    Cathodic arc plasma deposition has become the technology of choice for hard, wear and corrosion resistant coatings for a variety of applications. The history, basic physics of cathodic arc operation, the infamous macroparticle problem and common filter solutions, and emerging high-tech applications are briefly reviewed. Cathodic arc plasmas standout due to their high degree of ionization, with important consequences for film nucleation, growth, and efficient utilization of substrate bias. Industrial processes often use cathodic arc plasma in reactive mode. In contrast, the science of arcs has focused on the case of vacuum arcs. Future research directions include closing the knowledge gap for reactive mode, large area coating, linear sources and filters, metal plasma immersion process, with application in high-tech and biomedical fields.

  17. Taichi-inspired rigid-flexible coupling cellulose-supported solid polymer electrolyte for high-performance lithium batteries

    OpenAIRE

    Zhang, Jianjun; Yue, Liping; Hu, Pu; Liu, Zhihong; Qin, Bingsheng; Zhang, Bo; Wang, Qingfu; DING, GUOLIANG; Zhang, Chuanjian; Zhou, Xinhong; Yao, Jianhua; Cui, Guanglei; Chen, Liquan

    2014-01-01

    Inspired by Taichi, we proposed rigid-flexible coupling concept and herein developed a highly promising solid polymer electrolyte comprised of poly (ethylene oxide), poly (cyano acrylate), lithium bis(oxalate)borate and robust cellulose nonwoven. Our investigation revealed that this new class solid polymer electrolyte possessed comprehensive properties in high mechanical integrity strength, sufficient ionic conductivity (3 × 10−4 S cm−1) at 60°C and improved dimensional thermostability (up to...

  18. Janus Separator of Polypropylene-Supported Cellular Graphene Framework for Sulfur Cathodes with High Utilization in Lithium-Sulfur Batteries.

    Science.gov (United States)

    Peng, Hong-Jie; Wang, Dai-Wei; Huang, Jia-Qi; Cheng, Xin-Bing; Yuan, Zhe; Wei, Fei; Zhang, Qiang

    2016-01-01

    Owing to the conversion chemistry of the sulfur cathode, the lithium-sulfur (Li-S) batteries exhibit high theoretical energy density. However, the intrinsic mobile redox centers during the sulfur/Li2S-to-lithium polysulfides solid-to-liquid phase transition induce low sulfur utilization and poor cycling life. Herein, the Janus separator of mesoporous cellular graphene framework (CGF)/polypropylene membrane to promote the utilization of sulfur cathode is introduced. The porous polypropylene membrane serves as an insulating substrate in contact with lithium anode while CGFs that possess high electrical conductivity of 100 S cm(-1), a large mesopore volume of 3.1 cm(3) g(-1), and a huge surface area of 2120 m(2) g(-1) are adhered on cathode side to reactivate the shuttling-back polysulfides and to preserve the ion channels. Therefore, the Li-S cell with the "two-face" CGF Janus separator exhibit a high initial capacity of 1109 mAh g(-1) and superior capacity preserved upon 800 mAh g(-1) after 250 cycles at 0.2 C, which is 40% higher on sulfur utilization efficiency than the corresponding results with routine polypropylene separators. There are significant improvements on capacity as well as electrochemical kinetics. A very high areal capacity of 5.5 mAh cm(-2) combined with high sulfur content of 80% and areal loading amount of 5.3 mg cm(-2) is achieved for such advanced configuration. The negative impact of shuttle mechanism on lowering the utilization of sulfur and overall energy density of a Li-S battery is well eliminated by applying CGF separators. Consequently, employing carbonaceous materials as Janus face of separators enlightens new opportunities for improving the utilization of active materials and energy density of devices that involve complex phase evolution and conversion electrochemistry.

  19. Janus Separator of Polypropylene‐Supported Cellular Graphene Framework for Sulfur Cathodes with High Utilization in Lithium–Sulfur Batteries

    Science.gov (United States)

    Peng, Hong‐Jie; Wang, Dai‐Wei; Cheng, Xin‐Bing; Yuan, Zhe; Wei, Fei

    2016-01-01

    Owing to the conversion chemistry of the sulfur cathode, the lithium–sulfur (Li–S) batteries exhibit high theoretical energy density. However, the intrinsic mobile redox centers during the sulfur/Li2S‐to‐lithium polysulfides solid‐to‐liquid phase transition induce low sulfur utilization and poor cycling life. Herein, the Janus separator of mesoporous cellular graphene framework (CGF)/polypropylene membrane to promote the utilization of sulfur cathode is introduced. The porous polypropylene membrane serves as an insulating substrate in contact with lithium anode while CGFs that possess high electrical conductivity of 100 S cm−1, a large mesopore volume of 3.1 cm3 g−1, and a huge surface area of 2120 m2 g−1 are adhered on cathode side to reactivate the shuttling‐back polysulfides and to preserve the ion channels. Therefore, the Li–S cell with the “two‐face” CGF Janus separator exhibit a high initial capacity of 1109 mAh g−1 and superior capacity preserved upon 800 mAh g−1 after 250 cycles at 0.2 C, which is 40% higher on sulfur utilization efficiency than the corresponding results with routine polypropylene separators. There are significant improvements on capacity as well as electrochemical kinetics. A very high areal capacity of 5.5 mAh cm−2 combined with high sulfur content of 80% and areal loading amount of 5.3 mg cm−2 is achieved for such advanced configuration. The negative impact of shuttle mechanism on lowering the utilization of sulfur and overall energy density of a Li–S battery is well eliminated by applying CGF separators. Consequently, employing carbonaceous materials as Janus face of separators enlightens new opportunities for improving the utilization of active materials and energy density of devices that involve complex phase evolution and conversion electrochemistry.

  20. Inorganic salt mixtures as electrolyte media in fuel cells

    Science.gov (United States)

    Angell, Charles Austen (Inventor); Belieres, Jean-Philippe (Inventor); Francis-Gervasio, Dominic (Inventor)

    2012-01-01

    Fuel cell designs and techniques for converting chemical energy into electrical energy uses a fuel cell are disclosed. The designs and techniques include an anode to receive fuel, a cathode to receive oxygen, and an electrolyte chamber in the fuel cell, including an electrolyte medium, where the electrolyte medium includes an inorganic salt mixture in the fuel cell. The salt mixture includes pre-determined quantities of at least two salts chosen from a group consisting of ammonium trifluoromethanesulfonate, ammonium trifluoroacetate, and ammonium nitrate, to conduct charge from the anode to the cathode. The fuel cell includes an electrical circuit operatively coupled to the fuel cell to transport electrons from the cathode.

  1. Demonstrating the potential of yttrium-doped barium zirconate electrolyte for high-performance fuel cells

    Science.gov (United States)

    Bae, Kiho; Jang, Dong Young; Choi, Hyung Jong; Kim, Donghwan; Hong, Jongsup; Kim, Byung-Kook; Lee, Jong-Ho; Son, Ji-Won; Shim, Joon Hyung

    2017-02-01

    In reducing the high operating temperatures (>=800 °C) of solid-oxide fuel cells, use of protonic ceramics as an alternative electrolyte material is attractive due to their high conductivity and low activation energy in a low-temperature regime (fuel cells. However, poor sinterability of yttrium-doped barium zirconate discourages its fabrication as a thin-film electrolyte and integration on porous anode supports, both of which are essential to achieve high performance. Here we fabricate a protonic-ceramic fuel cell using a thin-film-deposited yttrium-doped barium zirconate electrolyte with no impeding grain boundaries owing to the columnar structure tightly integrated with nanogranular cathode and nanoporous anode supports, which to the best of our knowledge exhibits a record high-power output of up to an order of magnitude higher than those of other reported barium zirconate-based fuel cells.

  2. Break-down of Losses in High Performing Metal-Supported Solid Oxide Fuel Cells

    DEFF Research Database (Denmark)

    Kromp, Alexander; Nielsen, Jimmi; Blennow Tullmar, Peter;

    2012-01-01

    present the results of performance and stability improvements for a metal supported cell developed within the European project METSOFC and the Danish National Advanced Technology Foundation. The cells consist of a porous metal backbone, a metal / zirconia cermet anode and a 10ScYSZ electrolyte, cofired...... in hydrogen. The electrochemically active parts were applied by infiltrating CGO-Ni precursor solution into the porous metal and anode backbone and screenprinting (La,Sr)(Co,Fe)O3-based cathodes. To prevent a solid state reaction between cathode and zirconia electrolyte, CGO buffer layers were applied...... in between cathode and electrolyte. The detailed electrochemical characterization by means of impedance spectroscopy and a subsequent data analysis by the distribution of relaxation times enabled us to separate the different loss contributions in the cell. Based on an appropriate equivalent circuit model...

  3. Microscopic mechanisms of graphene electrolytic delamination from metal substrates

    Science.gov (United States)

    Fisichella, G.; Di Franco, S.; Roccaforte, F.; Ravesi, S.; Giannazzo, F.

    2014-06-01

    In this paper, hydrogen bubbling delamination of graphene (Gr) from copper using a strong electrolyte (KOH) water solution was performed, focusing on the effect of the KOH concentration (CKOH) on the Gr delamination rate. A factor of ˜10 decrease in the time required for the complete Gr delamination from Cu cathodes with the same geometry was found increasing CKOH from ˜0.05 M to ˜0.60 M. After transfer of the separated Gr membranes to SiO2 substrates by a highly reproducible thermo-compression printing method, an accurate atomic force microscopy investigation of the changes in Gr morphology as a function of CKOH was performed. Supported by these analyses, a microscopic model of the delamination process has been proposed, where a key role is played by graphene wrinkles acting as nucleation sites for H2 bubbles at the cathode perimeter. With this approach, the H2 supersaturation generated at the electrode for different electrolyte concentrations was estimated and the inverse dependence of td on CKOH was quantitatively explained. Although developed in the case of Cu, this analysis is generally valid and can be applied to describe the electrolytic delamination of graphene from several metal substrates.

  4. Taichi-inspired rigid-flexible coupling cellulose-supported solid polymer electrolyte for high-performance lithium batteries.

    Science.gov (United States)

    Zhang, Jianjun; Yue, Liping; Hu, Pu; Liu, Zhihong; Qin, Bingsheng; Zhang, Bo; Wang, Qingfu; Ding, Guoliang; Zhang, Chuanjian; Zhou, Xinhong; Yao, Jianhua; Cui, Guanglei; Chen, Liquan

    2014-09-03

    Inspired by Taichi, we proposed rigid-flexible coupling concept and herein developed a highly promising solid polymer electrolyte comprised of poly (ethylene oxide), poly (cyano acrylate), lithium bis(oxalate)borate and robust cellulose nonwoven. Our investigation revealed that this new class solid polymer electrolyte possessed comprehensive properties in high mechanical integrity strength, sufficient ionic conductivity (3 × 10(-4) S cm(-1)) at 60°C and improved dimensional thermostability (up to 160°C). In addition, the lithium iron phosphate (LiFePO4)/lithium (Li) cell using such solid polymer electrolyte displayed superior rate capacity (up to 6 C) and stable cycle performance at 80°C. Furthermore, the LiFePO4/Li battery could also operate very well even at an elevated temperature of 160°C, thus improving enhanced safety performance of lithium batteries. The use of this solid polymer electrolyte mitigates the safety risk and widens the operation temperature range of lithium batteries. Thus, this fascinating study demonstrates a proof of concept of the use of rigid-flexible coupling solid polymer electrolyte toward practical lithium battery applications with improved reliability and safety.

  5. Rational in-situ construction of three-dimensional reduced graphene oxide supported Li2S/C composite as enhanced cathode for rechargeable lithium-sulfur batteries

    Science.gov (United States)

    Wang, D. H.; Xia, X. H.; Xie, D.; Niu, X. Q.; Ge, X.; Gu, C. D.; Wang, X. L.; Tu, J. P.

    2015-12-01

    The construction of advanced cathode materials is indispensable and vital for developing high-performance lithium-sulfur batteries. Herein, we develop a facile in-situ route to synthesize three-dimensional reduced graphene oxide supported Li2S/carbon composite (3D-rGO-Li2S/C). The Li2S/C nanoparticles are intimately anchored on the surface of 3D-rGO forming an integrated 3D porous composite. Due to the improved conductivity and reduced polysulfide dissolution, the 3D-rGO-Li2S/C cathode exhibits enhanced electrochemical performances with a high initial capacity of 819 mAh g-1 at 0.1C, as well as good cycling stability with a capacity retention of 415 mAh g-1 after 100 cycles at 1C. The integrated 3D conductive network is responsible for the enhancement of the electrochemical properties by providing fast ion/electron transfer and high mechanical stability.

  6. Ba{sub 0.5}Sr{sub 0.5}Co{sub 0.8}Fe{sub 0.2}O{sub 3-{delta}} as a cathode for IT-SOFCs with a GDC interlayer

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Zaoshu; Yang, Min; Yan, Aiyu; Hou, Zifang; Dong, Yonglai; Chong, You; Cheng, Mojie; Yang, Weishen [Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China)

    2006-09-29

    The chemical compatibility of the Ba{sub 0.5}Sr{sub 0.5}Co{sub 0.8}Fe{sub 0.2}O{sub 3-{delta}} (BSCF) with the yttria-stabilized zirconia (YSZ) electrolyte or Gd-doped ceria electrolyte (GDC), as well as that of the GDC with the YSZ electrolyte were examined. It was found that BSCF had a good compatibility with the GDC electrolyte but a poor chemical compatibility with the YSZ electrolyte. The BSCF cathode was adopted for anode-supported YSZ electrolyte cells with and without the application of a 1{mu}m thick GDC buffering layer between the cathode and the YSZ electrolyte. The interfacial reactions of the BSCF with the YSZ electrolyte surface and the GDC coated YSZ surfaces were investigated. The single cells were evaluated by using I-V curve measurements and AC impedance spectroscopy. The results depicted a great improvement in cell performance and a significant decrease in polarization resistance after adding the GDC buffer layer. The optimum firing temperature of the GDC film onto the YSZ film was around 1250{sup o}C, which led to the maximum power density of 1.56Wcm{sup -2} at 800{sup o}C using air as oxidant and hydrogen as fuel. (author)

  7. Roles of Electrolyte Characterization on Bauxite Electrolysis Desulfurization with Regeneration and Recycling

    Science.gov (United States)

    Gong, Xuzhong; Wang, Zhi; Zhuang, Siyuan; Wang, Dong; Wang, Yuhua; Wang, Mingyong

    2016-10-01

    The recycling of NaCl used as supporting electrolyte for bauxite electrolysis was carried out in this study. The electrolyte was regenerated by adding anhydrous CaCl2 into the solution after filtration, and effects of electrolyte characterization on bauxite electrolysis were examined by observing the change in desulfurization ratio and cell voltage. The results indicated that the desulfurization ratio increased with increasing recycling times of electrolyte. In the meantime, the increase in recycling times has led to the decrease in pH value as well as the increase in Fe ion concentration in the electrolyte, which were the main reasons for the increase in the desulfurization ratio with increasing recycling of electrolyte. The pH value of electrolyte after second electrolysis was lower than 1.5, and the desulfurization ratio increased obviously due to the increase in Fe3+ concentration and suppression of jarosite formation. The increase in Ca2+ concentration did not apparently change desulfurization ratio and anode surface activity. However, with Ca2+ addition, the cathode surface was covered by CaSO4·nH2O, thus resulting in the increase of cell voltage.

  8. Roles of Electrolyte Characterization on Bauxite Electrolysis Desulfurization with Regeneration and Recycling

    Science.gov (United States)

    Gong, Xuzhong; Wang, Zhi; Zhuang, Siyuan; Wang, Dong; Wang, Yuhua; Wang, Mingyong

    2017-02-01

    The recycling of NaCl used as supporting electrolyte for bauxite electrolysis was carried out in this study. The electrolyte was regenerated by adding anhydrous CaCl2 into the solution after filtration, and effects of electrolyte characterization on bauxite electrolysis were examined by observing the change in desulfurization ratio and cell voltage. The results indicated that the desulfurization ratio increased with increasing recycling times of electrolyte. In the meantime, the increase in recycling times has led to the decrease in pH value as well as the increase in Fe ion concentration in the electrolyte, which were the main reasons for the increase in the desulfurization ratio with increasing recycling of electrolyte. The pH value of electrolyte after second electrolysis was lower than 1.5, and the desulfurization ratio increased obviously due to the increase in Fe3+ concentration and suppression of jarosite formation. The increase in Ca2+ concentration did not apparently change desulfurization ratio and anode surface activity. However, with Ca2+ addition, the cathode surface was covered by CaSO4·nH2O, thus resulting in the increase of cell voltage.

  9. Electrolytes for advanced batteries

    Energy Technology Data Exchange (ETDEWEB)

    Blomgren, G.E. [Energizer, Westlake, OH (United States)

    1999-09-01

    The choices of the components of the electrolyte phase for advanced batteries (lithium and lithium ion batteries) are very sensitive to the electrodes which are used. There are also a number of other requirements for the electrolyte phase, which depend on the cell design and the materials chosen for the battery. The difficulty of choice is compounded when the cell is a rechargeable one. This paper looks at each of these requirements and the degree to which they are met for lithium and lithium ion batteries. The discussion is broken into sections on anode or negative electrode stability requirements, cathode or positive electrode stability requirements, conductivity needs, viscosity and wetting requirements. The effects of these properties and interactions on the performance of batteries are also discussed. (orig.)

  10. Relationship between anode material, supporting electrolyte and current density during electrochemical degradation of organic compounds in water

    Energy Technology Data Exchange (ETDEWEB)

    Guzmán-Duque, Fernando L. [Grupo de diagnóstico y control de la contaminación, Facultad de ingeniería, Universidad de Antioquia, A.A. 1226, Medellín (Colombia); Palma-Goyes, Ricardo E. [Grupo de Investigación en Remediación Ambiental y Biocatálisis, Instituto de Química, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquía Udea, A.A. 1226, Medellín (Colombia); González, Ignacio [Universidad Autónoma Metropolitana-Iztapalapa, Departamento de Química, Av. San Rafael Atlixco No 186, C.P 09340, México D.F (Mexico); Peñuela, Gustavo [Grupo de diagnóstico y control de la contaminación, Facultad de ingeniería, Universidad de Antioquia, A.A. 1226, Medellín (Colombia); Torres-Palma, Ricardo A., E-mail: rtorres@matematicas.udea.edu.co [Grupo de Investigación en Remediación Ambiental y Biocatálisis, Instituto de Química, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquía Udea, A.A. 1226, Medellín (Colombia)

    2014-08-15

    Highlights: • Pathway and efficiency are linked to the current-electrode–electrolyte interaction. • Unlike BDD, IrO{sub 2} route was independent of current but dependent on the electrolyte. • IrO{sub 2}/SO{sub 4}{sup 2−} and IrO{sub 2}/Cl{sup −} routes were via IrO{sub 3} and chlorine species, respectively. • BDD/SO{sub 4}{sup 2−} and IrO{sub 2}/Cl{sup −} systems were favored at low and high currents, respectively. - Abstract: Taking crystal violet (CV) dye as pollutant model, the electrode, electrolyte and current density (i) relationship for electro-degrading organic molecules is discussed. Boron-doped diamond (BDD) or Iridium dioxide (IrO{sub 2}) used as anode materials were tested with Na{sub 2}SO{sub 4} or NaCl as electrolytes. CV degradation and generated oxidants showed that degradation pathways and efficiency are strongly linked to the current density-electrode–electrolyte interaction. With BDD, the degradation pathway depends on i: If i < the limiting current density (i{sub lim}), CV is mainly degraded by ·OH radicals, whereas if i > i{sub lim}, generated oxidants play a major role in the CV elimination. When IrO{sub 2} was used, CV removal was not dependent on i, but on the electrolyte. Pollutant degradation in Na{sub 2}SO{sub 4} on IrO{sub 2} seems to occur via IrO{sub 3}; however, in the presence of NaCl, degradation was dependent on the chlorinated oxidative species generated. In terms of efficiency, the Na{sub 2}SO{sub 4} electrolyte showed better results than NaCl when BDD anodes were employed. On the contrary, NaCl was superior when combined with IrO{sub 2}. Thus, the IrO{sub 2}/Cl{sup −} and BDD/SO{sub 4}{sup 2−} systems were better at removing the pollutant, being the former the most effective. On the other hand, pollutant degradation with the BDD/SO{sub 4}{sup 2−} and IrO{sub 2}/Cl{sup −} systems is favored at low and high current densities, respectively.

  11. Development of novel cathodes for high energy density lithium batteries

    Science.gov (United States)

    Bhargav, Amruth

    Lithium based batteries have become ubiquitous with our everyday life. They have propelled a generation of smart personal electronics and electric transport. Their use is now percolating to various fields as a source of energy to facilitate the operation of devices from nanoscale to mega scale. This need for a portable energy source has led to tremendous scientific interest in this field to develop electrochemical devices like batteries with higher capacities, longer cycle life and increased safety at a low cost. To this end, the research presented in this thesis focuses on two emerging and promising technologies called lithium-oxygen (Li-O2) and lithium-sulfur (Li-S) batteries. These batteries can offer an order of magnitude higher capacities through cheap, environmentally safe and abundant elements namely oxygen and sulfur. The first work introduces the concept of closed system lithium-oxygen batteries wherein the cell contains the discharge product of Li-O2 batteries namely, lithium peroxide (Li2O2) as the starting active material. The reversibility of this system is analyzed along with its rate performance. The possible use of such a cathode in a full cell is explored. Also, this concept is used to verify if all the lithium can be extracted from the cathode in the first charge. In the following work, lithium peroxide is chemically synthesized and deposited in a carbon nanofiber matrix. This forms a free standing cathode that shows high reversibility. It can be cycled up to 20 times and while using capacity control protocol, a cycle life of 50 is obtained. The cause of cell degradation and failure is also analyzed. In the work on full cell lithium-sulfur system, a novel electrolyte is developed that can support reversible lithium insertion and extraction from a graphite anode. A method to deposit solid lithium polysulfide is developed for the cathode. Coupling a lithiated graphite anode with the cathode using the new electrolyte yields a full cell whose

  12. 阴极支撑管式固体氧化物燃料电池%Cathode-supported tubular solid oxide fuel cells:a critical review

    Institute of Scientific and Technical Information of China (English)

    黄克勤

    2013-01-01

    This review provides a close look into the world leading cathodes-supported tubular solid ox-ide fuel cell (SOFC) technology. It starts from the basic facts of a SOFC,where the working principle,advantag-es,types and applications are specifically discussed. It then focuses on cathode-supported tubular SOFCs,one important branch of SOFCs,by providing detailed information on engineering innovations,materials advances, manufacturing processes and electrical performance of both traditional cylindrical and flattened ribbed tubular cells. The review ends with a high-level summary on the SOFC generator systems manufactured and demonstrat-ed by Siemens/Westinghouse over the past half-century.%  介绍了世界领先的阴极支撑管式固体氧化物燃料电池(SOFC)技术。从SOFC的基本组成开始阐述SOFC的工作原理、优点、类型及应用。作为SOFC的一个重要分支,重点讨论了阴极支撑管式SOFC,详细介绍了其工艺创新、材料、制备工艺,以及传统的圆管(cylindrical)和扁管电池的电性能。然后对过去半个世纪以来西门子/西屋公司制造并且示范验证的SOFC发电系统进行了详细的总结。

  13. High-performance lanthanum-ferrite-based cathode for SOFC

    DEFF Research Database (Denmark)

    Wang, W.G.; Mogensen, Mogens Bjerg

    2005-01-01

    (La0.6Sr0.4)(1-x)Co0.2Fe0.8O3/Ce0.9Gd0.1O3 (LSCF/CGO) composite cathodes were investigated for SOFC application at intermediate temperature, i.e., 500-700 degreesC. The LSCF/CGO cathodes have been studied on three types of tape-casted electrolyte substrates including CGO electrolyte, Yttrium......C were obtained using LSCF/CGO cathode on CGO electrolyte. On the YSZ electrolyte with thin layer CGO coating, R-p of 0.6 Omega cm(2) at 600 degreesC and 0.12 Omega cm(2) at 700 degreesC were obtained. On the YSZ electrolyte directly, R-p of 1.0 Omega cm(2) at 600 degreesC and 0.13 Omega cm(2) at 700...... degreesC were achieved. These results are roughly six times better than our typical LSM cathodes. Slightly higher R-s was observed in the samples with LSCF/CGO cathode on the YSZ electrolyte with CGO coating due to extra contribution from the thin CGO layer and the CGO/YSZ interface. For the samples...

  14. A Novel Cathode Material for Cathodic Dehalogenation of 1,1-Dibromo Cyclopropane Derivatives.

    Science.gov (United States)

    Gütz, Christoph; Selt, Maximilian; Bänziger, Markus; Bucher, Christoph; Römelt, Christina; Hecken, Nadine; Gallou, Fabrice; Galvão, Tomás R; Waldvogel, Siegfried R

    2015-09-28

    Leaded bronze turned out to be an excellent cathode material for the dehalogenation reaction of cyclopropanes without affecting the strained molecular entity. With this particular alloy, beneficial properties of lead cathodes are conserved, whereas the corrosion of cathode is efficiently suppressed. The solvent in the electrolyte determines whether a complete debromination reaction is achieved or if the process can be selectively stopped at the monobromo cyclopropane intermediate. The electroorganic conversion tolerates a variety of functional groups and can be conducted at rather complex substrates like cyclosporine A. This approach allows the sustainable preparation of cyclopropane derivatives.

  15. Silver vanadium oxide cathode material and method of preparation

    Energy Technology Data Exchange (ETDEWEB)

    Crespi, A.M.

    1993-06-22

    A method for making an electrochemical cell having the steps of admixing silver vanadium oxide with a conductive material and a binder and forming the admixture into a cathode, combining the cathode with a lithium metal anode; and combining an electrolyte with the anode and cathode, the method is described consisting of preparing the silver vanadium oxide by a chemical addition reaction consisting of admixing AgVO[sub 3] and V[sub 2]O[sub 5] in a 2:1 mole ratio heating the admixed AgVO[sub 3] and V[sub 3]O[sub 5] at a reaction temperature in the range of 300 C to 700 C for 5 to 24 hours. An electrochemical cell having a lithium metal anode, cathode and an electrolyte having a metal salt in a nonaqueous solvent comprising: the cathode including a crystalline silver vanadium oxide prepared by a chemical addition reaction.

  16. A Synopsis of Interfacial Phenomena in Lithium-Based Polymer Electrolyte Electrochemical Cells

    Science.gov (United States)

    Baldwin, Richard S.; Bennett, William R.

    2007-01-01

    The interfacial regions between electrode materials, electrolytes and other cell components play key roles in the overall performance of lithium-based batteries. For cell chemistries employing lithium metal, lithium alloy or carbonaceous materials (i.e., lithium-ion cells) as anode materials, a "solid electrolyte interphase" (SEI) layer forms at the anode/electrolyte interface, and the properties of this "passivating" layer significantly affect the practical cell/battery quality and performance. A thin, ionically-conducting SEI on the electrode surface can beneficially reduce or eliminate undesirable side reactions between the electrode and the electrolyte, which can result in a degradation in cell performance. The properties and phenomena attributable to the interfacial regions existing at both anode and cathode surfaces can be characterized to a large extent by electrochemical impedance spectroscopy (EIS) and related techniques. The intention of the review herewith is to support the future development of lithium-based polymer electrolytes by providing a synopsis of interfacial phenomena that is associated with cell chemistries employing either lithium metal or carbonaceous "composite" electrode structures which are interfaced with polymer electrolytes (i.e., "solvent-free" as well as "plasticized" polymer-binary salt complexes and single ion-conducting polyelectrolytes). Potential approaches to overcoming poor cell performance attributable to interfacial effects are discussed.

  17. Polymer electrolyte reviews. 1

    Energy Technology Data Exchange (ETDEWEB)

    Mac Callum, J.R.; Vincent, C.A.

    1987-01-01

    The development of polymer electrolytes which have potential applications in battery technology has resulted in an escalation of research into the synthesis of new macromolecular supports and the mechanisms of ionic transport within the solid matrix. Investigation of the properties of polymer electrolytes has brought together polymer chemists and electrochemists, and the understanding of the solubility and transport of electrolytes in organic polymers is now developing from this pooled experience. This book deals with experimental, theoretical and applied aspects of solid solutions of electrolytes used in coordinating polymer matrices. Attention is focused on the synthesis and properties of these new materials, the mechanisms of conduction processes and practical applications, especially with regard to battery technology.

  18. Chromium poisoning of LSM/YSZ and LSCF/CGO composite cathodes

    DEFF Research Database (Denmark)

    Bentzen, Janet Jonna; Høgh, Jens Valdemar Thorvald; Barfod, Rasmus;

    2009-01-01

    An electrochemical study of SOFC cathode degradation, due to poisoning by chromium oxide vapours, was performed applying 3-electrode set-ups. The cathode materials comprised LSM/YSZ and LSCF/CGO composites, whereas the electrolyte material was 8YSZ. The degradation of the cathode performance...... from 300 to 2,970 h. Both LSM/YSZ and LSCF/CGO cathodes were sensitive to chromium poisoning; LSCF/CGO cathodes to a lesser extent than LSM/YSZ. Humid air aggravated the degradation of the cathode performance. Post-mortem electron microscopic investigations revealed several Cr-containing compounds...

  19. Fabrication of anode supported PEN for solid oxide fuel cell

    Institute of Scientific and Technical Information of China (English)

    谢淑红; 崔崑; 夏风; 肖建中

    2004-01-01

    Fabrication process for anode supported planar PEN of intermediate temperature solid oxide fuel cell (SOFC) was introduced, in which tape casting and screen printing methods were used. Gd2O3 doped CeO2(GDC) powders were prepared by solid reaction method. Anode tape was produced by tape casting. Electrolyte and cathode were produced by screen printing. The GDC powder's component, thermal expand coefficient, the porosity, density and microstructure of anode and electrolyte were investigated . It was shown that an bi-layer with dense thin electrolyte film and porous anode support and with good coherency of the electrolyte film to the anode could be realized after co-sintering the green tape at 1 350℃ by optimizing the power characteristics of the starting materials in the slurry.

  20. Modeling the cathode in a proton exchange membrane fuel cell using density functional theory How the carbon support can affect durability and activity of a platinum catalyst

    Science.gov (United States)

    Groves, Michael Nelson

    The current global energy and environmental challenges need to be addressed by developing a new portfolio of clean power producing devices. The proton exchange membrane fuel cell has the potential to be included and can fit into a variety of niches ranging from portable electronics to stationary residential applications. One of the many barriers to commercial viability is the cost of the cathode layer which requires too much platinum metal to achieve a comparable power output as well as would need to be replaced more frequently when compared to conventional sources for most applications. Using density functional theory, an ab initio modeling technique, these durability and activity issues are examined for platinum catalysts on graphene and carbon nanotube supports. The carbon supports were also doped by replacing individual carbon atoms with other second row elements (beryllium, boron, nitrogen, and oxygen) and the effect on the platinum-surface interaction along with the interaction between the platinum and the oxygen reduction reaction intermediates are discussed. Keywords: proton exchange membrane fuel cell, density functional theory, platinum catalyst, oxygen reduction reaction, doped carbon surfaces

  1. Cathode materials: A personal perspective

    Energy Technology Data Exchange (ETDEWEB)

    Goodenough, John B. [Texas Materials Institute, University of Texas at Austin, ETC 9.102, 1 University Station, Austin, TX 78712-1063 (United States)

    2007-12-06

    A thermodynamically stable rechargeable battery has a voltage limited by the window of the electrolyte. An aqueous electrolyte has a window of 1.2 eV, which prevents achieving the high energy density desired for many applications. A non-aqueous electrolyte with a window of 5 eV requires Li{sup +} rather than H{sup +} as the working ion. Early experiments with Li{sub x}TiS{sub 2} cathodes showed competitive capacity and rate capability, but problems with a lithium anode made the voltage of a safe cell based on a sulfide cathode too low to be competitive with a nickel/metal-hydride battery. Transition-metal oxides can give voltages of 4.5 V versus Li{sup +}/Li{sup 0}. However, the challenge with oxides has been to obtain a competitive capacity and rate capability while retaining a high voltage with low-cost, environmentally friendly cathode materials. Comparisons will be made between layered Li{sub 1-x}MO{sub 2}, spinels Li{sub 1-x}[M{sub 2}]O{sub 4}, and olivines Li{sub 1-x}MPO{sub 4} having 0 < x < 1. Although higher capacities can be obtained with layered Li{sub 1-x}MO{sub 2} compounds, which have enabled the wireless revolution, their metastability makes them unlikely to be used in power applications. The spinel and olivine framework structures have been shown to be capable of charge/discharge rates of over 10C with a suitable temperature range for plug-in hybrid vehicles. (author)

  2. Towards the next generation of solid oxide fuel cells operating below 600 °c with chemically stable proton-conducting electrolytes.

    Science.gov (United States)

    Fabbri, Emiliana; Bi, Lei; Pergolesi, Daniele; Traversa, Enrico

    2012-01-10

    The need for reducing the solid oxide fuel cell (SOFC) operating temperature below 600 °C is imposed by cost reduction, which is essential for widespread SOFC use, but might also disclose new applications. To this aim, high-temperature proton-conducting (HTPC) oxides have gained widespread interest as electrolyte materials alternative to oxygen-ion conductors. This Progress Report describes recent developments in electrolyte, anode, and cathode materials for protonic SOFCs, addressing the issue of chemical stability, processability, and good power performance below 600 °C. Different fabrication methods are reported for anode-supported SOFCs, obtained using state-of-the-art, chemically stable proton-conducting electrolyte films. Recent findings show significant improvements in the power density output of cells based on doped barium zirconate electrolytes, pointing out towards the feasibility of the next generation of protonic SOFCs, including a good potential for the development of miniaturized SOFCs as portable power supplies.

  3. Polymer coatings as separator layers for microbial fuel cell cathodes

    KAUST Repository

    Watson, Valerie J.

    2011-03-01

    Membrane separators reduce oxygen flux from the cathode into the anolyte in microbial fuel cells (MFCs), but water accumulation and pH gradients between the separator and cathode reduces performance. Air cathodes were spray-coated (water-facing side) with anion exchange, cation exchange, and neutral polymer coatings of different thicknesses to incorporate the separator into the cathode. The anion exchange polymer coating resulted in greater power density (1167 ± 135 mW m-2) than a cation exchange coating (439 ± 2 mW m-2). This power output was similar to that produced by a Nafion-coated cathode (1114 ± 174 mW m-2), and slightly lower than the uncoated cathode (1384 ± 82 mW m-2). Thicker coatings reduced oxygen diffusion into the electrolyte and increased coulombic efficiency (CE = 56-64%) relative to an uncoated cathode (29 ± 8%), but decreased power production (255-574 mW m-2). Electrochemical characterization of the cathodes ex situ to the MFC showed that the cathodes with the lowest charge transfer resistance and the highest oxygen reduction activity produced the most power in MFC tests. The results on hydrophilic cathode separator layers revealed a trade off between power and CE. Cathodes coated with a thin coating of anion exchange polymer show promise for controlling oxygen transfer while minimally affecting power production. © 2010 Elsevier B.V. All rights reserved.

  4. Adsorptive Cathodic Stripping Voltammetric Determination of Cefoperazone in Bulk Powder, Pharmaceutical Dosage Forms, and Human Urine

    Science.gov (United States)

    Hoang, Vu Dang; Huyen, Dao Thi; Phuc, Phan Hong

    2013-01-01

    The electroreduction behaviour and determination of cefoperazone using a hanging mercury drop electrode were investigated. Cyclic voltammograms of cefoperazone recorded in universal Britton-Robinson buffers pH 3–6 exhibited a single irreversible cathodic peak. The process was adsorption-controlled. Britton-Robinson buffer 0.04 M pH 4.0 was selected as a supporting electrolyte for quantitative purposes by differential pulse and square wave adsorptive cathodic stripping voltammetry. The experimental voltammetric conditions were optimized using Central Composite Face design. A reduction wave was seen in the range from −0.7 to −0.8 V. These voltammetric techniques were successfully validated as per ICH guidelines and applied for the determination of cefoperazone in its single and sulbactam containing powders for injection and statistically comparable to USP-HPLC. They were further extended to determine cefoperazone in spiked human urine with no matrix effect. PMID:24109542

  5. Adsorptive Cathodic Stripping Voltammetric Determination of Cefoperazone in Bulk Powder, Pharmaceutical Dosage Forms, and Human Urine

    Directory of Open Access Journals (Sweden)

    Vu Dang Hoang

    2013-01-01

    Full Text Available The electroreduction behaviour and determination of cefoperazone using a hanging mercury drop electrode were investigated. Cyclic voltammograms of cefoperazone recorded in universal Britton-Robinson buffers pH 3–6 exhibited a single irreversible cathodic peak. The process was adsorption-controlled. Britton-Robinson buffer 0.04 M pH 4.0 was selected as a supporting electrolyte for quantitative purposes by differential pulse and square wave adsorptive cathodic stripping voltammetry. The experimental voltammetric conditions were optimized using Central Composite Face design. A reduction wave was seen in the range from −0.7 to −0.8 V. These voltammetric techniques were successfully validated as per ICH guidelines and applied for the determination of cefoperazone in its single and sulbactam containing powders for injection and statistically comparable to USP-HPLC. They were further extended to determine cefoperazone in spiked human urine with no matrix effect.

  6. The synthesis of Li(Cosbnd Mnsbnd Ni)O2 cathode material from spent-Li ion batteries and the proof of its functionality in aqueous lithium and sodium electrolytic solutions

    Science.gov (United States)

    Senćanski, Jelena; Bajuk-Bogdanović, Danica; Majstorović, Divna; Tchernychova, Elena; Papan, Jelena; Vujković, Milica

    2017-02-01

    Several spent Li-ion batteries were manually dismantled and their components were uncurled and separated. The chemical composition of each battery's component was determined by atomic absorption spectroscopy. Among several ways to separate cathode material from the collector, the alkali dissolution treatment was selected as the most effective one. After both complete separation and acid leaching steps, the co-precipitation method, followed by a thermal treatment (700 °C or 850 °C), was used to resynthesize cathode material LiCo0.415Mn0.435Ni0.15O2. Its structure and morphology were characterized by XRD, Raman spectroscopy and SEM-EDS methods. The electrochemical behavior of recycled cathode materials was examined by cyclic voltammetry and chronopotentiometry in both LiNO3 and NaNO3 aqueous solutions. High sodium storage capacity, amounting to 93 mAh g-1, was measured galvanostatically at a relatively high current of ∼100 mA g-1. Initial lithium intercalation capacity of ∼64 mAh g-1, was determined potentiodynamically at very high scan rate of 20 mV s-1 (∼40 C). Somewhat lower initial capacity of ∼30 mAh g-1, but much lower capacity fade on cycling, was found for sodium intercalation at the same scan rate. The differences in the Li and Na charge storage capability were explained in terms of ion rearrangement during charging/discharging processes.

  7. 2013 Estorm - Invited Paper - Cathode Materials Review

    Energy Technology Data Exchange (ETDEWEB)

    Daniel, Claus [ORNL; Mohanty, Debasish [ORNL; Li, Jianlin [ORNL; Wood III, David L [ORNL

    2014-01-01

    The electrochemical potential of cathode materials defines the positive side of the terminal voltage of a battery. Traditionally, cathode materials are the energy-limiting or voltage-limiting electrode. One of the first electrochemical batteries, the voltaic pile invented by Alessandro Volta in 1800 (Phil. Trans. Roy. Soc. 90, 403 431) had a copper-zinc galvanic element with a terminal voltage of 0.76 V. Since then, the research community has increased capacity and voltage for primary (nonrechargeable) batteries and round-trip efficiency for secondary (rechargeable) batteries. Successful secondary batteries have been the lead acid with a lead oxide cathode and a terminal voltage of 2.1 V and later the NiCd with a nickel(III) oxide hydroxide cathode and a 1.2 V terminal voltage. The relatively low voltage of those aqueous systems and the low round-trip efficiency due to activation energies in the conversion reactions limited their use. In 1976, Wittingham (J. Electrochem. Soc., 123, 315) and Besenhard (J Power Sources 1(3), 267) finally enabled highly reversible redox reactions by intercalation of lithium ions instead of by chemical conversion. In 1980, Goodenough and Mizushima (Mater. Res. Bull. 15, 783 789) demonstrated a high-energy and high-power LiCoO2 cathode, allowing for an increase of terminal voltage far beyond 3 V. Over the past four decades, the international research community has further developed cathode materials of many varieties. Current state-of-the-art cathodes demonstrate voltages beyond any known electrolyte stability window, bringing electrolyte research once again to the forefront of battery research.

  8. Electrogenerated chemiluminescence of tris(2,2' bipyridine)ruthenium(II) using common biological buffers as co-reactant, pH buffer and supporting electrolyte.

    Science.gov (United States)

    Kebede, Noah; Francis, Paul S; Barbante, Gregory J; Hogan, Conor F

    2015-11-07

    A series of aliphatic tertiary amines (HEPES, POPSO, EPPS and BIS-TRIS) commonly used to buffer the pH in biological experiments, were examined as alternative, non-toxic co-reactants for the electrogenerated chemiluminescence (ECL) of tris(2,2'-bipyridine)ruthenium(ii) ([Ru(bpy)3](2+)). These were found to be very attractive as "multi-tasking" reagents, serving not only as co-reactants, but also fulfiling the roles of pH buffer and supporting electrolyte within an aqueous environment; thus significantly simplifying the overall ECL analysis. Sub-nanomolar detection limits were obtained for [Ru(bpy)3](2+) in the presence of BIS-TRIS, making this species an valuable option for co-reactant ECL-based bioanalytical applications.

  9. Application of electrospun CNx nanofibers as cathode in microfluidic fuel cell

    Science.gov (United States)

    Jindal, Amandeep; Basu, Suddhasatwa; Chauhan, Neha; Ukai, Tomofumi; Kumar, D. Sakthi; Samudhyatha, K. T.

    2017-02-01

    Carbon nitride (CNx) nanofibers is successfully utilised as cathode catalyst in microfluidic fuel cell (MFC) using electrospinning technique. The electrochemical measurement for CNx nanofibers as cathode catalyst in MFC is studied and compared with that of Pt and Au cathodes. Formic acid is employed as fuel, KMnO4 as oxidant and H2SO4 as supporting electrolyte. CNx nanofibers is shown to be not active towards formic acid oxidation and as a result, is tolerant to fuel crossover effect as compared to Pt and Au cathode. CNx nanofibers enable MFC to operate at a wider range of flow rates of fuel and oxidant as compared to Pt and Au conventionally used. MFC utilising CNx nanofibers gives higher power density of 3.43 mW cm-2 and the current density of 9.79 mAcm-2, as compared to that utilizes pure Au (2.72 mW cm-2, 6.04 mA cm-2) and Pt (3.09 mW cm-2, 6.18 mA cm-2) as anode.

  10. Novel cathodes for low-temperature solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Liu, M.; Xia, C. [Georgia Inst. of Tech., Atlanta, GA (United States). Center for Innovative Fuel Cell and Battery Technologies

    2002-04-04

    A solid-oxide fuel cell that operates at 500 C (instead of 600 C and higher), with lower material cost and better long-term stability, is presented. Its key piece is a cathode made of a silver/copper-doped bismuth vanadate (Ag-BI-CUVOX) composite, which reduces oxygen at lower temperatures and diminishes the resistance between the cathode and the electrolyte. (orig.)

  11. Low-cost polyvinyl alcohol hydrogel membrane electrolyte for PEM fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Sahai, Y. [Ohio State Univ., Columbus, OH (United States). Dept. of Materials Science and Engineering

    2010-07-01

    This paper presented a newly developed polyvinyl alcohol (PVA) chemical hydrogel membrane electrolyte (PCHME) for use in proton exchange membrane (PEM) fuel cells. The method of PCHME preparation was described along with its properties. The membrane is much less expensive than the commonly used Nafion membrane. A direct borohydride fuel cell (DBFC) using a polyvinyl alcohol (PVA) chemical hydrogel membrane electrolyte and a nickel-based composite anode was assembled in order to test the performance of the new membrane. The cathode catalysts were carbon-supported platinum and sputtered gold. Oxygen, air, and acidified hydrogen peroxide were used as oxidants in the DBFC. Performance characteristics of the PCHME-based DBFC were obtained at different temperatures and compared with similar DBFCs using Nafion membrane electrolytes under the same operating conditions. The peak power density of the PCHME-based DBFC was somewhat higher than that of the Nafion membrane electrolyte based DBFC at 60 degrees C. The borohydride-oxygen fuel cell with PCHME yielded a maximum peak power density of 242 mW cm{sup -2} at 60 degrees C. It was concluded that the membrane presents an inexpensive alternative to widely used polymer membrane electrolytes.

  12. Lithium-Air Batteries with Hybrid Electrolytes.

    Science.gov (United States)

    He, Ping; Zhang, Tao; Jiang, Jie; Zhou, Haoshen

    2016-04-07

    During the past decade, Li-air batteries with hybrid electrolytes have attracted a great deal of attention because of their exceptionally high capacity. Introducing aqueous solutions and ceramic lithium superionic conductors to Li-air batteries can circumvent some of the drawbacks of conventional Li-O2 batteries such as decomposition of organic electrolytes, corrosion of Li metal from humidity, and insoluble discharge product blocking the air electrode. The performance of this smart design battery depends essentially on the property and structure of the cell components (i.e., hybrid electrolyte, Li anode, and air cathode). In recent years, extensive efforts toward aqueous electrolyte-based Li-air batteries have been dedicated to developing the high catalytic activity of the cathode as well as enhancing the conductivity and stability of the hybrid electrolyte. Herein, the progress of all aspects of Li-air batteries with hybrid electrolytes is reviewed. Moreover, some suggestions and concepts for tailored design that are expected to promote research in this field are provided.

  13. A Hydrogen-Evolving Hybrid-Electrolyte Battery with Electrochemical/Photoelectrochemical Charging from Water Oxidation.

    Science.gov (United States)

    Jin, Zhaoyu; Li, Panpan; Xiao, Dan

    2017-02-08

    Decoupled hydrogen and oxygen production were successfully embedded into an aqueous dual-electrolyte (acid-base) battery for simultaneous energy storage and conversion. A three-electrode configuration was adopted, involving an electrocatalytic hydrogen-evolving electrode as cathode, an alkaline battery-type or capacitor-type anode as shuttle, and a charging-assisting electrode for electro-/photoelectrochemically catalyzing water oxidation. The conceptual battery not only synergistically outputs electricity and chemical fuels with tremendous specific energy and power densities, but also supports various approaches to be charged by pure or solar-assisted electricity.

  14. Liquid cathode primary batteries

    Science.gov (United States)

    Schlaikjer, Carl R.

    1985-03-01

    Lithium/liquid cathode/carbon primary batteries offer from 3 to 6 times the volumetric energy density of zinc/alkaline manganese cells, improved stability during elevated temperature storage, satisfactory operation at temperatures from -40 to +150 °C, and efficient discharge at moderate rates. he lithium/sulfur dioxide cell is the most efficient system at temperatures below 0 °C. Although chemical reactions leading to electrolyte degradation and lithium corrosion are known, the rates of these reactions are slow. While the normal temperature cell reaction produces lithium dithionite, discharge at 60 °C leads to a reduction in capacity due to side reactions involving sulfur dioxide and discharge intermediates. Lithium/thionyl chloride and lithium/sulfuryl chloride cells have the highest practical gravimetric and volumetric energy densities when compared with aqueous and most other nonaqueous systems. For thionyl chloride, discharge proceeds through a series of intermediates to sulfur, sulfur dioxide and lithium chloride. Catalysis, leading to improved rate capability and capacity, has been achieved. The causes of rapid reactions leading to thermal runaway are thought to be chemical in nature. Lithium/sulfuryl chloride cells, which produce sulfur dioxide and lithium chloride on discharge, experience more extensive anode corrosion. An inorganic cosolvent and suitable salt are capable of alleviating this corrosion. Calcium/oxyhalide cells have been studied because of their promise of increased safety without substantial sacrifice of energy density relative to lithium cells. Anode corrosion, particularly during discharge, has delayed practical development.

  15. Liquid cathode primary batteries

    Energy Technology Data Exchange (ETDEWEB)

    Schlaikjer, C.R.

    1985-01-15

    Lithium/liquid cathode/carbon primary batteries offer from 3 to 6 times the volumetric energy density of zinc/alkaline manganese cells, improved stability during elevated temperature storage, satisfactory operation at temperatures from -40 to +150/sup 0/C, and efficient discharge at moderate rates. The lithium/sulfur dioxide cell is the most efficient system at temperatures below 0/sup 0/C. Although chemical reactions leading to electrolyte degradation and lithium corrosion are known, the rates of these reactions are slow. While the normal temperature cell reaction produces lithium dithionite, discharge at 60/sup 0/C leads to a reduction in capacity due to side reactions involving sulfur dioxide and discharge intermediates. Lithium/thionyl chloride and lithium/sulfuryl chloride cells have the highest practical gravimetric and volumetric energy densities when compared with aqueous and most other nonaqueous systems. For thionyl chloride, discharge proceeds through a series of intermediates to sulfur, sulfur dioxide and lithium chloride. Catalysis, leading to improved rate capability and capacity, has been achieved. The causes of rapid reactions leading to thermal runaway are thought to be chemical in nature. Lithium/sulfuryl chloride cells, which produce sulfur dioxide and lithium chloride on discharge, experience more extensive anode corrosion. An inorganic cosolvent and suitable salt are capable of alleviating this corrosion. Calcium/oxyhalide cells have been studied because of their promise of increased safety without substantial sacrifice of energy density relative to lithium cells. Anode corrosion, particularly during discharge, has delayed practical development.

  16. The Influence of Polymer Binders on the Performance of Cathodes for Lithium-Ion Batteries

    OpenAIRE

    Barsykov, V; V. Khomenko

    2001-01-01

    A systematic electrochemical investigation is performed to study the effect of polyvinylidene difluoride (PVDF) based polymer binders on the performance of different cathodes for lithium-ion batteries in ionic liquid (IL) based electrolytes. Electrochemical tests indicate that the nature of PVDF effects significantly on cathode stability in IL based electrolytes. The copolymer such as hexafluoropropylene (HFP) plays a significant role in the interfacial resistance. Application of PVDF-HFP bi...

  17. Hexagonal NiS nanobelts as advanced cathode materials for rechargeable Al-ion batteries.

    Science.gov (United States)

    Yu, Zhijing; Kang, Zepeng; Hu, Zongqian; Lu, Jianhong; Zhou, Zhigang; Jiao, Shuqiang

    2016-08-16

    Hexagonal NiS nanobelts served as novel cathode materials for rechargeable Al-ion batteries based on an AlCl3/[EMIm]Cl ionic liquid electrolyte system. The nano-banded structure of the materials can facilitate the electrolyte immersion and enhance Al(3+) diffusion. The hexagonal NiS nanobelt based cathodes exhibit high storage capacity, good cyclability and low overpotential.

  18. The Effect of Platinum Electrocatalyst on Membrane Degradation in Polymer Electrolyte Fuel Cells.

    Science.gov (United States)

    Bodner, Merit; Cermenek, Bernd; Rami, Mija; Hacker, Viktor

    2015-12-08

    Membrane degradation is a severe factor limiting the lifetime of polymer electrolyte fuel cells. Therefore, obtaining a deeper knowledge is fundamental in order to establish fuel cells as competitive product. A segmented single cell was operated under open circuit voltage with alternating relative humidity. The influence of the catalyst layer on membrane degradation was evaluated by measuring a membrane without electrodes and a membrane-electrode-assembly under identical conditions. After 100 h of accelerated stress testing the proton conductivity of membrane samples near the anode and cathode was investigated by means of ex situ electrochemical impedance spectroscopy. The membrane sample near the cathode inlet exhibited twofold lower membrane resistance and a resulting twofold higher proton conductivity than the membrane sample near the anode inlet. The results from the fluoride ion analysis have shown that the presence of platinum reduces the fluoride emission rate; which supports conclusions drawn from the literature.

  19. Solid state electrolyte systems

    Energy Technology Data Exchange (ETDEWEB)

    Pederson, L.R.; Armstrong, B.L.; Armstrong, T.R. [Pacific Northwest Lab., Richland, WA (United States)] [and others

    1997-12-01

    Lanthanum gallates are a new family of solid electrolytes that exhibit high ionic conductivity and are stable to high temperatures. Compositions have been developed that are as much as a factor of two more conductive than yttria-stabilized zirconia at a given temperature, through partial replacement of lanthanum by calcium, strontium, and/or barium and through partial replacement of gallium by magnesium. Oxide powders were prepared using combustion synthesis techniques developed in this laboratory; these were sintered to >95% of theoretical density and consisted of a single crystalline phase. Electrical conductivities, electron and ion transference numbers, thermal expansion, and phase behavior were evaluated as a function of temperature and oxygen partial pressure. A key advantage of the use of lanthanum gallate electrolytes in solid oxide fuel cells is that the temperature of operation may be lowered to perhaps 800 C, yet provide approximately the same power density as zirconia-based cells operating at 1000 C. Ceramic electrolytes that conduct both oxygen ions and electrons are potentially useful to passively separate pure oxygen from an air source at low cost. In such materials, an oxygen ion flux in one direction is charge-compensated by an opposing electron flux. The authors have examined a wide range of mixed ion and electron conducting perovskite ceramics in the system La{sub 1{minus}x}M{sub x}Co{sub 1{minus}y{minus}z}Fe{sub y}N{sub z}O{sub 3{minus}{delta}}, where M = Sr, Ca, and Ba, and N = Pr, Mn, Ni, Cu, Ti, and Al, as well as mixed conducting brownmillerite ceramics, and have characterized oxygen permeation behavior, defect chemistry, structural and phase stability, and performance as cathodes.

  20. Mechanism of Reaction in NaAlCl4 Molten Salt Batteries with Nickel Felt Cathodes and Aluminum Anodes. Part II: Experimental Results and Comparison with Model Calculations

    DEFF Research Database (Denmark)

    Knutz, B.C.; Berg, Rolf W.; Hjuler, Hans Aage;

    1993-01-01

    and cyclability can be obtained with systems containing dissolved chalcogen compared with the chalcogen-free system. Exchange of chalcogen between cathode and electrolyte during cycling was confirmed by performing gravimetric analysis and Raman spectroscopy of the electrolytes. Cathode reactions were studied...

  1. The phase-shift method for determining Langmuir and Temkin adsorption isotherms of over-potentially deposited hydrogen for the cathodic H{sub 2} evolution reaction at the poly-Pt/H{sub 2}SO{sub 4} aqueous electrolyte interface

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Jang H.; Jeon, Sang K.; Kim, Nam Y. [Department of Electronic Engineering, Kwangwoon University, Seoul 139-701 (Korea); Chun, Jin Y. [School of Chemical Engineering, Seoul National University, Seoul 151-744 (Korea)

    2005-11-01

    A linear relationship between the behavior (-f vs. E) of the phase shift (0{sup |}=<-f=<90{sup |}) for the optimum intermediate frequency and that ({theta} vs. E) of the fractional surface coverage (1>={theta}>=0) of over-potentially deposited hydrogen (OPD H) for the cathodic H{sub 2} evolution reaction (HER), i.e., the phase-shift method, at the poly-Pt/0.5M H{sub 2}SO{sub 4} aqueous electrolyte interface has been verified using cyclic voltammetric, differential pulse voltammetric, and ac impedance techniques. The phase-shift method for determining the suitable adsorption isotherm (Langmuir, Frumkin, Temkin) of OPD H for the cathodic HER at the interface also has been proposed. At the poly-Pt/0.5M H{sub 2}SO{sub 4} aqueous electrolyte interface, the Langmuir adsorption isotherm ({theta} vs. E) of OPD H, the equilibrium constant (K=1.3x10{sup -4}) for OPD H and the standard free energy ({delta}G{sub ads}{sup 0}=22.2kJ/mol) of OPD H are determined using the phase-shift method. At the same interface, the Temkin adsorption isotherm ({theta} vs. E) of OPD H, the equilibrium constant (1.3x10{sup -3}>=K>=1.3x10{sup -5} with {theta}, i.e., 0=<{theta}=<1) for OPD H, and the standard free energy (16.5=<{delta}G{sub {theta}}{sup 0}=<27.9kJ/mol with {theta}, i.e., 0=<{theta}=<1) of OPD H are also determined using the phase-shift method. At the intermediate values of {theta}, i.e., 0.2<{theta}<0.8, the Langmuir and Temkin adsorption isotherms of OPD H for the cathodic HER at the interface are converted to each other. The equilibrium constant (K{sub 0}) for the Temkin adsorption isotherm ({theta} vs. E) is ca. 10 times greater than that (K) for the corresponding Langmuir adsorption isotherm ({theta} vs. E). The interaction parameter (g) for the Temkin adsorption isotherm ({theta} vs. E) is ca. 4.6 greater than that (g) for the corresponding Langmuir adsorption isotherm ({theta} vs. E). These numbers (10 times and 4.6) can be taken as constant conversion factors between the

  2. On the role of reactant transport and (surface) alloy formation for the CO tolerance of carbon supported PtRu polymer electrolyte fuel cell catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Kaiser, J.; Colmenares, L.; Jusys, Z.; Behm, R.J. [Abt. Oberflaechenchemie und Katalyse, Universitaet Ulm (Germany); Moertel, R.; Boennemann, H. [Max-Planck-Institut fuer Kohlenforschung, Muelheim a.d. Ruhr (Germany); Koehl, G.; Modrow, H.; Hormes, J. [Physikalisches Institut, Universitaet Bonn (Germany)

    2006-07-15

    The role of atomic scale intermixing for the electrocatalytic activity of bimetallic PtRu anode catalysts in reformate operated polymer electrolyte fuel cells (PEFC) was investigated, exploiting the specific properties of colloid based catalyst synthesis for the selective preparation of alloyed and non-alloyed bimetallic catalysts. Three different carbon supported PtRu catalysts with different degrees of Pt and Ru intermixing, consisting of (i) carbon supported PtRu alloy particles (PtRu/C), (ii) Pt and Ru particles co-deposited on the same carbon support (Pt+Ru/C), and (iii) a mixture of carbon supported Pt and carbon supported Ru (Pt/C+Ru/C) as well as the respective monometallic Pt/C and Ru/C catalysts were prepared and characterized by electron microscopy (TEM), X-ray absorption spectroscopy, and CO stripping. Their performance as PEFC anode catalysts was evaluated by oxidation of a H{sub 2}/2%CO gas mixture (simulated reformate) under fuel cell relevant conditions (elevated temperature, continuous reaction and controlled reactant transport) in a rotating disk electrode (RDE) set-up. The CO tolerance and H{sub 2} oxidation activity of the three catalysts is comparable and distinctly different from that of the monometallic catalysts. The results indicate significant transport of the reactants, CO{sub ad} and/or OH{sub ad}, between Pt and Ru surface areas and particles for all three catalysts, with only subtle differences from the alloy catalyst to the physical mixture. The high activity and CO tolerance of the bimetallic catalysts, through the formation of bimetallic surfaces, is explained, e.g., by contact formation in nanoparticle agglomerates or by material transport and subsequent surface decoration/surface alloy formation during catalyst preparation, conditioning, and operation. The instability and mobility of the catalysts under these conditions closely resembles concepts in gas phase catalysis. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  3. SOFC LSM:YSZ cathode degradation induced by moisture: An impedance spectroscopy study

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Mogensen, Mogens Bjerg

    2011-01-01

    The cause of the degradation effect of moisture during operation of LSM cathode based SOFCs has been investigated by means of a detailed impedance characterization on LSM:YSZ composite cathode based SOFCs. Further the role of YSZ as cathode composite material was studied by measurements on SOFCs...... with a LSM:CGO composite cathode on a CGO interdiffusion barrier layer. It was found that both types of cathodes showed similar electrochemical characteristics towards the presence of moisture during operation. Upon addition and removal of moisture in the fed air the impedance study showed a change...... in the high frequency cathode arc, which is associated with the charge transport/transfer at the LSM/YSZ interface. On prolonged operation with the presence of moisture an ongoing increase in the high frequency cathode arc resulted in a permanent loss of cathode/electrolyte contact and thus increase...

  4. Polymeric electrolytes for ambient temperature lithium batteries

    Science.gov (United States)

    Farrington, G. C.

    1987-09-01

    During this reporting period a number of novel solid polymer electrolytes formed by salts of multivalent cations and polyethylene oxide (PEO) have been prepared and characterized. These materials are of interest not only because of their potential ionic conductivities, but also because some of them may have electronic conductivity and oxidizing power which would be useful for novel electrode materials in all-solid-state batteries. Two broad classes of materials were investigated: PEO solutions of Zn(2), Cd(2), and Pb(2), all of which are potential electrolytes for solid-state batteries, and PEO solutions of transition metal salts, which are of interest as possible cathode materials. Mixed compositions containing both divalent cations and lithium ions were also prepared. Electrolytes formed with small, highly-polarizing ions, such as Mg(2) and Ca(2), are essentially pure anion conductors. Electrolytes containing Zn(2) behave similarly, unless they are hydrated, in which case the Zn(2) ions are quite mobile. Electrolytes formed with larger, more polarizable cations, such as Pb(2) and Cd(2), conduct both anions and cations. Solutions of salts of transition metal cations form a third group of electrolytes. Of the electrolytes investigated so far, those formed with Ni(++) salts are the most unusual. It appears as if the transport number of Ni(2) and the electrolyte conductivity can be greatly enhanced by controlling the hydration and dehydration of the polymer.

  5. The reduction mechanism at the mercury electrode in a 0.9 M NaClO4+0.1 M HClO4 supporting electrolyte of an hydroxytriphenylmethane: Eriochrome Cyanine R

    NARCIS (Netherlands)

    Boodts, J.F.C.; Sluyters-Rehbach, M.; Sluyters, J.H.

    1979-01-01

    The reduction mechanism at a mercury electrode of Eriochrome Cyanine R, in a 0.9 M NaClO4+0.1 M HClO4 supporting electrolyte, has been investigated by several electrochemical techniques. By means of coulometry at constant potential and cyclic voltammetry it was demonstrated that a radical is formed,

  6. Synchrotron Investigations of SOFC Cathode Degradation

    Energy Technology Data Exchange (ETDEWEB)

    Idzerda, Yves

    2013-09-30

    The atomic variations occurring in cathode/electrolyte interface regions of La{sub 1-x}Sr{sub x}Co{sub y}Fe{sub 1-y}O{sub 3-δ} (LSCF) cathodes and other SOFC related materials have been investigated and characterized using soft X-ray Absorption Spectroscopy (XAS) and diffuse soft X-ray Resonant Scattering (XRS). X-ray Absorption Spectroscopy in the soft X-ray region (soft XAS) is shown to be a sensitive technique to quantify the disruption that occurs and can be used to suggest a concrete mechanism for the degradation. For LSC, LSF, and LSCF films, a significant degradation mechanism is shown to be Sr out-diffusion. By using the XAS spectra of hexavalent Cr in SrCrO4 and trivalent Cr in Cr2O3, the driving factor for Sr segregation was identified to be the oxygen vacancy concentration at the anode and cathode side of of symmetric LSCF/GDC/LSCF heterostructures. This is direct evidence of vacancy induced cation diffusion and is shown to be a significant indicator of cathode/electrolyte interfacial degradation. X-ray absorption spectroscopy is used to identify the occupation of the A-sites and B-sites for LSC, LSF, and LSCF cathodes doped with other transition metals, including doping induced migration of Sr to the anti-site for Sr, a significant cathode degradation indicator. By using spatially resolved valence mapping of Co, a complete picture of the surface electrochemistry can be determined. This is especially important in identifying degradation phenomena where the degradation is spatially localized to the extremities of the electrochemistry and not the average. For samples that have electrochemical parameters that are measured to be spatially uniform, the Co valence modifications were correlated to the effects of current density, overpotential, and humidity.

  7. Effect of samarium doped ceria nanoparticles impregnation on the performance of anode supported SOFC with(Pr_(0.7)Ca_(0.3))_(0.9)MnO_(3-δ) cathode

    Institute of Scientific and Technical Information of China (English)

    熊麟; 王绍荣; 王振荣; 温珽琏

    2010-01-01

    Solid oxide fuel cell(SOFC) electrodes,after a high temperature sintering,may be impregnated to deposit nanoparticles within their pores to enhance the catalytic function.Samarium doped CeO2(SDC) nanoparticles were infiltrated into(Pr0.7Ca0.3)0.9MnO3-δ(PCM) cathode of anode supported SOFC cells.The cell with 2.6 mg/cm2 SDC impregnated in cathode showed the maximum power density of 580 mW/cm2 compared with 310 mW/cm2 of the cell without impregnation at 850 °C.The cells were also characterized with the impeda...

  8. Final Report: Wetted Cathodes for Low-Temperature Aluminum Smelting

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Craig W

    2002-09-30

    A low-temperature aluminum smelting process being developed differs from the Hall-Heroult process in several significant ways. The low-temperature process employs a more acidic electrolyte than cryolite, an alumina slurry, oxygen-generating metal anodes, and vertically suspended electrodes. Wetted and drained vertical cathodes are crucial to the new process. Such cathodes represent a significant portion of the capital costs projected for the new technology. Although studies exist of wetted cathode technology with Hall-Heoult cells, the differences make such a study desirable with the new process.

  9. Electrolytes Test

    Science.gov (United States)

    ... mean? High or low electrolyte levels can be caused by several conditions and diseases. Generally, they are affected by how much is consumed in the diet and absorbed by the body, the amount of water in a person's body, and the amount eliminated ...

  10. Self-Passivating Lithium/Solid Electrolyte/Iodine Cells

    Science.gov (United States)

    Bugga, Ratnakumar; Whitcare, Jay; Narayanan, Sekharipuram; West, William

    2006-01-01

    Robust lithium/solid electrolyte/iodine electrochemical cells that offer significant advantages over commercial lithium/ iodine cells have been developed. At room temperature, these cells can be discharged at current densities 10 to 30 times those of commercial lithium/iodine cells. Moreover, from room temperature up to 80 C, the maximum discharge-current densities of these cells exceed those of all other solid-electrolyte-based cells. A cell of this type includes a metallic lithium anode in contact with a commercial flexible solid electrolyte film that, in turn, is in contact with an iodine/ graphite cathode. The solid electrolyte (the chemical composition of which has not been reported) offers the high ionic conductivity needed for high cell performance. However, the solid electrolyte exhibits an undesirable chemical reactivity to lithium that, if not mitigated, would render the solid electrolyte unsuitable for use in a lithium cell. In this cell, such mitigation is affected by the formation of a thin passivating layer of lithium iodide at the anode/electrolyte interface. Test cells of this type were fabricated from iodine/graphite cathode pellets, free-standing solid-electrolyte films, and lithium-foil anodes. The cathode mixtures were made by grinding together blends of nominally 10 weight percent graphite and 90 weight percent iodine. The cathode mixtures were then pressed into pellets at 36 kpsi (248 MPa) and inserted into coin-shaped stainless-steel cell cases that were coated with graphite paste to minimize corrosion. The solid-electrolyte film material was stamped to form circular pieces to fit in the coin cell cases, inserted in the cases, and pressed against the cathode pellets with polyethylene gaskets. Lithium-foil anodes were placed directly onto the electrolyte films. The layers described thus far were pressed and held together by stainless- steel shims, wave springs, and coin cell caps. The assembled cells were then crimped to form hermetic seals

  11. Novel Nonflammable Electrolytes for Secondary Magnesium Batteries and High Voltage Electrolytes for Electrochemcial Supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, Brian

    2008-12-30

    Magnesium has been used successfully in primary batteries, but its use in rechargeable cells has been stymied by the lack of suitable non-aqueous electrolyte that can conduct Mg+2 species, combined with poor stripping and plating properties. The development of a suitable cathode material for rechargeable magnesium batteries has also been a roadblock, but a nonflammable electrolyte is key. Likewise, the development of safe high voltage electrochemical supercapaitors has been stymied by the use of flammable solvents in the liquid electrolyte; to wit, acetonitrile. The purpose of the research conducted in this effort was to identify useful compositions of magnesium salts and polyphosphate solvents that would enable magnesium ions to be cycled within a secondary battery design. The polyphosphate solvents would provide the solvent for the magnesium salts while preventing the electrolyte from being flammable. This would enable these novel electrolytes to be considered as an alternative to THF-based electrolytes. In addition, we explored several of these solvents together with lithium slats for use as high voltage electrolytes for carbon-based electrochemical supercapacitors. The research was successful in that: 1) Magnesium imide dissolved in a phosphate ester solvent that contains a halogented phosphate ester appears to be the preferred electrolyte for a rechargeable Mg cell. 2) A combination of B-doped CNTs and vanadium phosphate appear to be the cathode of choice for a rechargeable Mg cell by virtue of higher voltage and better reversibility. 3) Magnesium alloys appear to perform better than pure magnesium when used in combination with the novel polyphosphate electrolytes. Also, this effort has established that Phoenix Innovation's family of phosphonate/phosphate electrolytes together with specific lithium slats can be used in supercapacitor systems at voltages of greater than 10V.

  12. Alkali-Resistant Quasi-Solid-State Electrolyte for Stretchable Supercapacitors.

    Science.gov (United States)

    Tang, Qianqiu; Wang, Wenqiang; Wang, Gengchao

    2016-10-05

    Research on stretchable energy-storage devices has been motivated by elastic electronics, and considerable research efforts have been devoted to the development of stretchable electrodes. However, stretchable electrolytes, another critical component in stretchable devices, have earned quite little attention, especially the alkali-resistant ones. Here, we reported a novel stretchable alkali-resistant electrolyte made of a polyolefin elastomer porous membrane supported potassium hydroxide-potassium polyacrylate (POE@KOH-PAAK). The as-prepared electrolyte shows a negligible plastic deformation even after 1000 stretching cycles at a strain of 150% as well as a high conductivity of 0.14 S cm(-1). It also exhibits excellent alkali resistance, which shows no obvious degradation of the mechanical performance after immersion in 2 M KOH for up to 2 weeks. To demonstrate its good properties, a high-performance stretchable supercapacitor is assembled using a carbon-nanotube-film-supported NiCo2O4 (CNT@NiCo2O4) as the cathode and Fe2O3 (CNT@Fe2O3) as the anode, proving great application promise of the stretchable alkali-resistant electrolyte in stretchable energy-storage devices.

  13. Stability of Conductive Carbon Additives for High-voltage Li-ion Battery Cathodes

    OpenAIRE

    Nilssen, Benedicte Eikeland

    2014-01-01

    Conductive carbon additives are important constituents of the current state-of-the-art Li-ion battery cathodes, as the traditional active cathode materials are characterized by too low electronic conductivities. In high-voltage Li-ion batteries, these additives are subject for anion intercalation and electrolyte oxidation, which might cause changes in the conductive carbon network in the cathode, and hence the overall cycling performance of the electrode. This thesis has focused on study the ...

  14. Voltammetric and electrochemical impedance spectroscopy characterization of a cathodic and anodic pre-treated boron doped diamond electrode

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, S. Carlos B. [Departamento de Quimica, Faculdade de Ciencias e Tecnologia, Universidade de Coimbra, 3004-535 Coimbra (Portugal); Oliveira-Brett, Ana Maria, E-mail: brett@ci.uc.p [Departamento de Quimica, Faculdade de Ciencias e Tecnologia, Universidade de Coimbra, 3004-535 Coimbra (Portugal)

    2010-06-01

    The effect of boron doped diamond (BDD) surface termination, immediately after cathodic and anodic electrochemical pre-treatments, on the electrochemical response of a BDD electrode in aqueous media and the influence of the different supporting electrolytes utilized in these pre-treatments on the final surface termination was investigated with [Fe(CN){sub 6}]{sup 4-/3-}, as redox probe, by cyclic and differential pulse voltammetry and electrochemical impedance spectroscopy. The cyclic voltammetry results indicate that the electrochemical behavior for the redox couple [Fe(CN){sub 6}]{sup 4-/3-} is very dependent on the state of the BDD surface, and a reversible response was observed after the cathodic electrochemical pre-treatment, whereas a quasi-reversible response occurred after anodic electrochemical pre-treatment. Differential pulse voltammetry in acetate buffer also showed that the potential window is very much influenced by the electrochemical pre-treatment of the BDD surface. Electroactivity of non-diamond carbon surface species (sp{sup 2} inclusions) incorporated into the diamond structure was observed after cathodic and anodic pre-treatments. Electrochemical impedance spectroscopy confirmed the cyclic voltammetry results and indicates that the BDD surface resistance and capacitance vary significantly with the electrolyte and with the electrochemical pre-treatment, caused by different surface terminations of the BDD electrode surface.

  15. Multifunctional Electrolytes for Abuse-Tolerant 5V Li-ion Space Batteries Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase I project will develop a multifunctional electrolyte for high energy density abuse-tolerant lithium ion batteries with 5 V cathodes such as LiCoPO4....

  16. MODELING THE ELECTROLYTIC DECHLORINATION OF TRICHLOROETHYLENE IN A GRANULAR GRAPHITE-PACKED REACTOR

    Science.gov (United States)

    A comprehensive reactor model was developed for the electrolytic dechlorination of trichloroethylene (TCE) at a granular-graphite cathode. The reactor model describes the dynamic processes of TCE dechlorination and adsorption, and the formation and dechlorination of all the major...

  17. Surface science investigations of SEI layer in Li-ion battery cathodes. Oxidation states and surface reactions

    Energy Technology Data Exchange (ETDEWEB)

    Cherkashinin, G.; Ensling, D.; Schmid, S.; Bhuvaneswari, S.; Song, J.; Jacke, S.; Jaegermann, W. [Technische Univ. Darmstadt (Germany). Fachbereich Materialwissenschaft; Nikolowski, K.; Ehrenberg, H. [Institut fuer Festkoerper- und Werkstofforschung Dresden e.V. (Germany). Inst. for Complex Materials

    2010-07-01

    Surface electronic properties of the promising Li-ion cathode materials such as LiMo{sub 2} (Ni, Co, Mn) and LiFePO{sub 4} as well as evolution of electrolyte-cathode interfaces formed after contact to the electrolyte, due to electrochemical charging and after cycling were systematically studied using conventional electronic spectroscopy methods (XPS, UPS) and synchrotron photoelectron spectroscopy (SXPS, XAS). To study fundamental surface properties of the oxides we investigated both thin film cathodes in-situ, where the surfaces are not contaminated by impurities, and synthesized powder cathodes used in industry. (orig.)

  18. Lithium-Ion Electrolytes with Improved Safety Tolerance to High Voltage Systems

    Science.gov (United States)

    Smart, Marshall C. (Inventor); Bugga, Ratnakumar V. (Inventor); Prakash, Surya G. (Inventor); Krause, Frederick C. (Inventor)

    2015-01-01

    The invention discloses various embodiments of electrolytes for use in lithium-ion batteries, the electrolytes having improved safety and the ability to operate with high capacity anodes and high voltage cathodes. In one embodiment there is provided an electrolyte for use in a lithium-ion battery comprising an anode and a high voltage cathode. The electrolyte has a mixture of a cyclic carbonate of ethylene carbonate (EC) or mono-fluoroethylene carbonate (FEC) co-solvent, ethyl methyl carbonate (EMC), a flame retardant additive, a lithium salt, and an electrolyte additive that improves compatibility and performance of the lithium-ion battery with a high voltage cathode. The lithium-ion battery is charged to a voltage in a range of from about 2.0 V (Volts) to about 5.0 V (Volts).

  19. Industrial experiment of copper electrolyte purification by copper arsenite

    Institute of Scientific and Technical Information of China (English)

    ZHENG Ya-jie; XIAO Fa-xin; WANG Yong; LI Chun-hua; XU Wei; JIAN Hong-sheng; MA Yut-ian

    2008-01-01

    Copper electrolyte was purified by copper arsenite that was prepared with As2O3. And electrolysis experiments of purified electrolyte were carried out at 235 and 305 A/m2, respectively. The results show that the yield of copper arsenite is up to 98.64% when the molar ratio of Cu to As is 1.5 in the preparation of copper arsenite. The removal rates of Sb and Bi reach 74.11% and 65.60% respectively after copper arsenite is added in electrolyte. The concentrations of As, Sb and Bi in electrolyte nearly remain constant during electrolysis of 13 d. The appearances of cathode copper obtained at 235 and 305 A/m2 are slippery and even, and the qualification rate is 100% according to the Chinese standard of high-pure cathode copper(GB/T467-97).

  20. Valence states and surface/interface reactions in Li-ion battery cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Cherkashinin, Gennady; Ensling, David; Schmid, Stefan; Song, Jie; Jacke, Susanne; Hausbrand, Rene; Jaegermann, Wolfram [Department of Materials Science, Surface Science Institute, Darmstadt University of Technology (Germany); Nikolowski, Kristian; Ehrenberg, Helmut [IFW Dresden, Institute for Complex Materials (Germany)

    2010-07-01

    Surface electronic properties of promising Li-Ion cathode materials such as LiMO{sub 2} (Ni,Co,Mn) as well as evolution of electrolyte-cathode interfaces formed after contact to the electrolyte, due to electrochemical charging and after cycling were systematically studied using XPS, UPS and synchrotron photoelectron spectroscopy (SXPS,XAS). To study fundamental surface properties of the oxides we investigated both thin film cathodes in-situ, whose surfaces are not contaminated by impurities, and synthesized powder cathodes used in industry. For LiMO{sub 2} (Ni,Co,Mn) cathodes, we have found that contact of the cathodes to the electrolyte results in the loss of lattice lithium and in the formation of a solid electrolyte interface (SEI) layer consisting of Li{sub 2}CO{sub 3}, Li{sub x}O{sub y}, LiF (if LiPF{sub 6}-electrolyte is used) and other species. For oxides containing Ni{sup 3+}, we observe a Ni{sup 3+} to Ni{sup 2+} reduction. Charging of Li{sub x}(M)O{sub 2} (M=Co,Ni) does not only lead to Co{sup 3+} to Co{sup 4+} oxidation but also to oxygen deficiency. We detect no oxygen site participation in the charge compensation at the initial stage of the Li-de-intercalation.

  1. Insight into the interaction between layered lithium-rich oxide and additive-containing electrolyte

    Science.gov (United States)

    Tu, Wenqiang; Xia, Pan; Zheng, Xiongwen; Ye, Changchun; Xu, Mengqiang; Li, Weishan

    2017-02-01

    Electrolyte additives have been found to be effective for the cyclic stability improvement of layered lithium-rich oxide (LRO), which is ascribed to the formation of cathode films derived from the preferential oxidation of the electrolyte additives. However, the detailed mechanism on the formation of the cathode film is unclear. This paper uncovers the interaction between LRO and additive-containing electrolyte through theoretical calculations, electrochemical measurements and physical characterizations. A representative LRO, Li1.2Mn0.54Ni0.13Co0.13O2, is synthesized, and an electrolyte, 1 M LiPF6 in EC/DMC (1/2, in volume) using triethyl phosphite (TEP) as additive, is considered. Charge/discharge tests demonstrate that LRO suffers severe capacity fading and TEP can significantly improve the cyclic stability of LRO. Characterizations from SEM and TEM demonstrate that a cathode film exists on the LRO after cycling in the TEP-containing electrolyte. The theoretical calculations suggest that TEP traps the active oxygen and is then oxidized on LRO preferentially compared to the electrolyte, forming the cathode film. The further characterizations from FTIR and GC, confirm that the preferential combination of TEP with active oxygen is beneficial for the suppression of oxygen evolution, and that the resulting cathode film can suppress the electrolyte decomposition and protect LRO from destruction.

  2. Electrolytic fixer.

    Science.gov (United States)

    Stevens

    1982-12-01

    Interest in the recovery of silver from radiographic film generates a need to understand the operating procedures of recovery units utilizing the electrolytic fixer principle. Tailing or terminal units and recirculation units using electrolysis are evaluated. Difficulties encountered in the number of Coulombs applied to a specific amount of fixer are discussed. Reduction of sulfiding as a result of electrolysis and variations in film volumes are noted. The quantity and quality of silver collected can be improved by being aware of alterations in chemical activity used in a silver recovery program.

  3. A definitive criterion for cathodic protection

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, Roger [Cathodic Protection Network International Ltd., Reading (United Kingdom)

    2009-07-01

    The corrosion reaction is defined using the Pourbaix Diagram and includes consideration of the pH, temperature, pressure, nobility of the metal and conductivity of the electrolyte. The passive zone can be established in a laboratory by creating a closed circuit condition in which the voltages can be measured. Natural corrosion cells occurring in simple conditions can be evaluated for the purpose of monitoring the performance of cathodic protection. Metal pipelines are complex networks of conductors submerged in electrolyte of infinitely variable qualities. The present method used to ascertain the effectiveness of cathodic protection has many inherent errors and results in costly and unpredictable corrosion failures. An electrode has been devised to define the exact electrical status of the corrosion reaction at its location. The design allows a closed circuit measurement of the corrosion current that can determine whether or not corrosion has been stopped by cathodic protection. This has allowed the development of software that can calculate the condition and corrosion status throughout a network of pipelines, using electrical circuit analysis common in the electronics industry. (author)

  4. A cobalt-free perovskite-type La{sub 0.6}Sr{sub 0.4}Fe{sub 0.9}Cr{sub 0.1}O{sub 3-{alpha}} cathode for proton-conducting intermediate temperature solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Zuolong; Yang, Zhijie; Zhao, Dongmei; Deng, Xuli [Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Ma, Guilin, E-mail: 32uumagl@suda.edu.cn [Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China)

    2013-02-15

    Highlights: Black-Right-Pointing-Pointer A cobalt-free cathode material LSFC10 for IT-SOFCs was prepared and studied in detail. Black-Right-Pointing-Pointer The conductivity of LSFC10 reached 138 S cm{sup -1} under oxygen at 550 Degree-Sign C. Black-Right-Pointing-Pointer An anode-supported BZCY electrolyte membrane was successfully fabricated by a simple spin coating process. Black-Right-Pointing-Pointer Power density of the ceramic membrane fuel cell using LSFC10 as cathode reached 412 mW cm{sup -2} at 700 Degree-Sign C. - Abstract: A cobalt-free perovskite-type cathode material La{sub 0.6}Sr{sub 0.4}Fe{sub 0.9}Cr{sub 0.1}O{sub 3-{alpha}} (LSFC10) was prepared by a citric acid-nitrate process and investigated as a potential cathode material for proton-conducting intermediate-temperature solid oxide fuel cells (IT-SOFCs). The maximum conductivity of LSFC10 reached 138 S cm{sup -1} under oxygen at 550 Degree-Sign C. A Ni-BZCY composite anode-supported proton-conducting BaZr{sub 0.1}Ce{sub 0.7}Y{sub 0.2}O{sub 3-{alpha}} (BZCY) electrolyte membrane was successfully fabricated by a simple, cost-effective spin coating process. The peak power densities of the H{sub 2}/O{sub 2} fuel cell using BZCY electrolyte membrane, Ni-BZCY composite anode and LSFC10 cathode reached 412 mW cm{sup -2}, and the interfacial polarization resistance for the fuel cell was as low as 0.19 {Omega} cm{sup 2} under open circuit conditions, at 700 Degree-Sign C. These results reveal LSFC10 is a suitable cathode material for proton-conducting IT-SOFCs.

  5. Electrochemical performance of all-solid-state Li batteries based LiMn{sub 0.5}Ni{sub 0.5}O{sub 2} cathode and NASICON-type electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Xie, J.; Zhao, X.B.; Cao, G.S. [Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Imanishi, N.; Zhang, T.; Hirano, A.; Takeda, Y.; Yamamoto, O. [Department of Chemistry, Faculty of Engineering, Mie University, 1577 Kurimamachiya-cho, Tsu, Mie 514-8507 (Japan)

    2010-12-15

    LiNi{sub 0.5}Mn{sub 0.5}O{sub 2} thin films have been deposited on the NASICON-type glass ceramics, Li{sub 1+x+y}Al{sub x}Ti{sub 2-x}Si{sub y}P{sub 3-y}O{sub 12} (LATSP), by radio frequency (RF) magnetron sputtering followed by annealing. The films have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Raman spectroscopy. All-solid-state Li/PEO{sub 18}-Li(CF{sub 3}SO{sub 2}){sub 2}N/LATSP/LiNi{sub 0.5}Mn{sub 0.5}O{sub 2}/Au cells are fabricated using the LiNi{sub 0.5}Mn{sub 0.5}O{sub 2} thin films and the LATSP electrolyte. The electrochemical performance of the cells is investigated by galvanostatic cycling, cyclic voltammetry (CV), potentiostatic intermittent titration technique (PITT) and electrochemical impedance spectroscopy (EIS). Interfacial reactions between LiNi{sub 0.5}Mn{sub 0.5}O{sub 2} and LATSP occur at a temperature as low as 300 C with the formation of Mn{sub 3}O{sub 4}, resulting in an increased obstacle for Li-ion diffusion across the LiNi{sub 0.5}Mn{sub 0.5}O{sub 2}/LATSP interface. The electrochemical performance of the cells is limited by the interfacial resistance between LATSP and LiNi{sub 0.5}Mn{sub 0.5}O{sub 2} as well as the Li-ion diffusion kinetics in LiNi{sub 0.5}Mn{sub 0.5}O{sub 2} bulk. (author)

  6. Planar-Focusing Cathodes

    CERN Document Server

    Lewellen, J W

    2005-01-01

    Conventional pi-mode rf photoinjectors typically use magnetic solenoids for emittance compensation. This provides independent focusing strength, but can complicate rf power feed placement, introduce asymmetries (due to coil crossovers), and greatly increase the cost of the photoinjector. Cathode-region focusing can also provide for a form of emittance compensation. Typically this method strongly couples focusing strength to the field gradient on the cathode, however, and also requires altering the longitudinal position of the cathode to change the focusing. We propose a new method for achieving cathode-region variable-strength focusing for emittance compensation. The new method reduces the coupling to the gradient on the cathode, and does not require a change in the longitudinal position of the cathode. Expected performance for an S-band system is similar to conventional solenoid-based designs. This paper presents the results of rf cavity and beam dynamics simulations of the new design.

  7. Durable rechargeable zinc-air batteries with neutral electrolyte and manganese oxide catalyst

    Science.gov (United States)

    Sumboja, Afriyanti; Ge, Xiaoming; Zheng, Guangyuan; Goh, F. W. Thomas; Hor, T. S. Andy; Zong, Yun; Liu, Zhaolin

    2016-11-01

    Neutral chloride-based electrolyte and directly grown manganese oxide on carbon paper are used as the electrolyte and air cathode respectively for rechargeable Zn-air batteries. Oxygen reduction and oxygen evolution reactions on manganese oxide show dependence of activities on the pH of the electrolyte. Zn-air batteries with chloride-based electrolyte and manganese oxide catalyst exhibit satisfactory voltage profile (discharge and charge voltage of 1 and 2 V at 1 mA cm-2) and excellent cycling stability (≈90 days of continuous cycle test), which is attributed to the reduced carbon corrosion on the air cathode and decreased carbonation in neutral electrolyte. This work describes a robust electrolyte system that improves the cycle life of rechargeable Zn-air batteries.

  8. Solidified inorganic-organic hybrid electrolyte for all solid state flexible lithium battery

    Science.gov (United States)

    Baek, Seung-Wook; Honma, Itaru; Kim, Jedeok; Rangappa, Dinesh

    2017-03-01

    Solidified lithium conducting hybrid electrolyte is designed and processed to realize the large scale and flexible solid state Li battery satisfying energy capability and safety issue. This paper presents a solidified inorganic-organic hybrid electrolyte to obtain commercially-acceptable ionic conductivity and a stable electrochemical window to prevent electrolyte decomposition in Li ion batteries. Li3PO4 coated with solidified [Li][EMI][TFSI] ionic liquid is developed as hybrid electrolyte material. The material has high electrochemical stability on a high-voltage cathode and metallic anode, and the solid electrolyte has high ionic conductivity. This Li3PO4-[Li][EMI][TFSI] hybrid electrolyte has the advantages of long-term operation, safety and flexibility, so it may be suitable for use in high-voltage cathodes and Li anode.

  9. Numerical simulation on electrolyte flow field in 156 kA drained aluminum reduction cells

    Institute of Scientific and Technical Information of China (English)

    ZHOU Nai-jun; XIA xiao-xia; WANG Fu-qiang

    2007-01-01

    Based on the commercial CFD software CFX-4.3, two-phase flow of electrolyte in 156 kA drained aluminum reduction cells with a new structure was numerically simulated by multi-fluid model and k-εturbulence model. The results show that the electrolyte flow in the drained cells is more even than in the conventional cells. Corresponding to center point feeding,the electrolyte flow in the drained cells is more advantageous to the release of anode gas, the dissolution and diflusion of alumina, and the gradient reduction of the electrolyte density and temperature. The average velocity of the electrolyte is 8.3 cm/s, and the maximum velocity is 59.5 cm/s.The average and maximum velocities of the gas are 23.2 cm/s and 61.1 cm/s, respectively. The cathode drained slope and anode cathode distance have certain effects on the electrolyte flow.

  10. Fabrication and performance of PEN SOFCs with proton-conducting electrolyte

    Institute of Scientific and Technical Information of China (English)

    ZHONG Li; LUO Jingli

    2007-01-01

    A positive-electrolyte-negative (PEN) assembly solid oxide fuel cell (SOFC) with a thin electrolyte film for intermediate temperature operation was fabricated.Instead of the traditional screen-printing method,both anode and cathode catalysts were pressed simultaneously and formed with the fabrication of nano-composite electrolyte by press method.This design offered some advantageous configurations that diminished ohmic resistance between electrolyte and electrodes.It also increased the proton-conducting rate and improved the performance of SOFCs due to the reduction of membrane thickness and good contact between electrolyte and electrodes.The fabricated PEN cell generated electricity between 600℃ and 680~C using H2S as fuel feed and Ni-S-based composite anode,nano-composite electrolyte (Li2SO4 + Al2O3) film and a NiO-based composite cathode were achieved at 600℃ and 680℃,respectively.

  11. REMOVAL OF COPPER ELECTROLYTE CONTAMINANTS BY ADSORPTION

    Directory of Open Access Journals (Sweden)

    B Gabai

    1997-09-01

    Full Text Available Abstract - Selective adsorbents have become frequently used in industrial processes. Recent studies have shown the possibility of using adsorption to separate copper refinery electrolyte contaminants, with better results than those obtained with conventional techniques. During copper electrorefinning, many impurities may be found as dissolved metals present in the anode slime which forms on the electrode surface, accumulated in the electrolyte or incorporated into the refined copper on the cathode by deposition. In this study, synthetic zeolites, chelating resins and activated carbons were tested as adsorbents to select the best adsorbent performance, as well as the best operating temperature for the process. The experimental method applied was the finite bath, which consists in bringing the adsorbent into contact with a finite volume of electrolyte while controlling the temperature. The concentration of metals in the liquid phase was continuously monitored by atomic absorption spectrophotometry (AAS

  12. Cathodic Protection Model Facility

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Performs Navy design and engineering of ship and submarine impressed current cathodic protection (ICCP) systems for underwater hull corrosion control and...

  13. Al2O3 Disk Supported Si3N4 Hydrogen Purification Membrane for Low Temperature Polymer Electrolyte Membrane Fuel Cells

    Directory of Open Access Journals (Sweden)

    Xiaoteng Liu

    2013-12-01

    Full Text Available Reformate gas, a commonly employed fuel for polymer electrolyte membrane fuel cells (PEMFCs, contains carbon monoxide, which poisons Pt-containing anodes in such devices. A novel, low-cost mesoporous Si3N4 selective gas separation material was tested as a hydrogen clean-up membrane to remove CO from simulated feed gas to single-cell PEMFC, employing Nafion as the polymer electrolyte membrane. Polarization and power density measurements and gas chromatography showed a clear effect of separating the CO from the gas mixture; the performance and durability of the fuel cell was thereby significantly improved.

  14. Lithium air batteries having ether-based electrolytes

    Science.gov (United States)

    Amine, Khalil; Curtiss, Larry A.; Lu, Jun; Lau, Kah Chun; Zhang, Zhengcheng; Sun, Yang-Kook

    2016-10-25

    A lithium-air battery includes a cathode including a porous active carbon material, a separator, an anode including lithium, and an electrolyte including a lithium salt and polyalkylene glycol ether, where the porous active carbon material is free of a metal-based catalyst.

  15. Demonstrating the potential of yttrium-doped barium zirconate electrolyte for high-performance fuel cells.

    Science.gov (United States)

    Bae, Kiho; Jang, Dong Young; Choi, Hyung Jong; Kim, Donghwan; Hong, Jongsup; Kim, Byung-Kook; Lee, Jong-Ho; Son, Ji-Won; Shim, Joon Hyung

    2017-02-23

    In reducing the high operating temperatures (≥800 °C) of solid-oxide fuel cells, use of protonic ceramics as an alternative electrolyte material is attractive due to their high conductivity and low activation energy in a low-temperature regime (≤600 °C). Among many protonic ceramics, yttrium-doped barium zirconate has attracted attention due to its excellent chemical stability, which is the main issue in protonic-ceramic fuel cells. However, poor sinterability of yttrium-doped barium zirconate discourages its fabrication as a thin-film electrolyte and integration on porous anode supports, both of which are essential to achieve high performance. Here we fabricate a protonic-ceramic fuel cell using a thin-film-deposited yttrium-doped barium zirconate electrolyte with no impeding grain boundaries owing to the columnar structure tightly integrated with nanogranular cathode and nanoporous anode supports, which to the best of our knowledge exhibits a record high-power output of up to an order of magnitude higher than those of other reported barium zirconate-based fuel cells.

  16. INFLUENCES OF PH AND CURRENT ON ELECTROLYTIC DECHLORINATION OF TRICHLOROETHYLENE AT A GRANULAR-GRAPHITE PACKED ELECTRODE

    Science.gov (United States)

    Electrolytic dechlorination using a granular-graphite packed cathode is an alternative method for the remediation of chlorinated organic compounds. Its effectiveness under various conditions needs experimental investigation. Dechlorination of trichloroethylene (TCE) was conducted...

  17. NiP₂ nanosheet arrays supported on carbon cloth: an efficient 3D hydrogen evolution cathode in both acidic and alkaline solutions.

    Science.gov (United States)

    Jiang, Ping; Liu, Qian; Sun, Xuping

    2014-11-21

    Designing efficient and stable hydrogen evolution catalysts made from earth-abundant elements is essential to the development of solar-driven water-splitting devices. In this communication, we develop a two-step strategy for constructing NiP2 nanosheet arrays on carbon cloth (NiP2 NS/CC). As a novel 3D hydrogen evolution cathode, the NiP2 NS/CC electrode is highly active in acidic solutions and needs an overpotential of 75 and 204 mV to achieve current densities of 10 and 100 mA cm(-2), respectively, and it preserves its catalytic activity for at least 57 h. Moreover, it also operates efficiently under alkaline conditions.

  18. Batteries: Overview of Battery Cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Doeff, Marca M

    2010-07-12

    The very high theoretical capacity of lithium (3829 mAh/g) provided a compelling rationale from the 1970's onward for development of rechargeable batteries employing the elemental metal as an anode. The realization that some transition metal compounds undergo reductive lithium intercalation reactions reversibly allowed use of these materials as cathodes in these devices, most notably, TiS{sub 2}. Another intercalation compound, LiCoO{sub 2}, was described shortly thereafter but, because it was produced in the discharged state, was not considered to be of interest by battery companies at the time. Due to difficulties with the rechargeability of lithium and related safety concerns, however, alternative anodes were sought. The graphite intercalation compound (GIC) LiC{sub 6} was considered an attractive candidate but the high reactivity with commonly used electrolytic solutions containing organic solvents was recognized as a significant impediment to its use. The development of electrolytes that allowed the formation of a solid electrolyte interface (SEI) on surfaces of the carbon particles was a breakthrough that enabled commercialization of Li-ion batteries. In 1990, Sony announced the first commercial batteries based on a dual Li ion intercalation system. These devices are assembled in the discharged state, so that it is convenient to employ a prelithiated cathode such as LiCoO{sub 2} with the commonly used graphite anode. After charging, the batteries are ready to power devices. The practical realization of high energy density Li-ion batteries revolutionized the portable electronics industry, as evidenced by the widespread market penetration of mobile phones, laptop computers, digital music players, and other lightweight devices since the early 1990s. In 2009, worldwide sales of Li-ion batteries for these applications alone were US$ 7 billion. Furthermore, their performance characteristics (Figure 1) make them attractive for traction applications such as

  19. Batteries: Overview of Battery Cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Doeff, Marca M

    2010-07-12

    The very high theoretical capacity of lithium (3829 mAh/g) provided a compelling rationale from the 1970's onward for development of rechargeable batteries employing the elemental metal as an anode. The realization that some transition metal compounds undergo reductive lithium intercalation reactions reversibly allowed use of these materials as cathodes in these devices, most notably, TiS{sub 2}. Another intercalation compound, LiCoO{sub 2}, was described shortly thereafter but, because it was produced in the discharged state, was not considered to be of interest by battery companies at the time. Due to difficulties with the rechargeability of lithium and related safety concerns, however, alternative anodes were sought. The graphite intercalation compound (GIC) LiC{sub 6} was considered an attractive candidate but the high reactivity with commonly used electrolytic solutions containing organic solvents was recognized as a significant impediment to its use. The development of electrolytes that allowed the formation of a solid electrolyte interface (SEI) on surfaces of the carbon particles was a breakthrough that enabled commercialization of Li-ion batteries. In 1990, Sony announced the first commercial batteries based on a dual Li ion intercalation system. These devices are assembled in the discharged state, so that it is convenient to employ a prelithiated cathode such as LiCoO{sub 2} with the commonly used graphite anode. After charging, the batteries are ready to power devices. The practical realization of high energy density Li-ion batteries revolutionized the portable electronics industry, as evidenced by the widespread market penetration of mobile phones, laptop computers, digital music players, and other lightweight devices since the early 1990s. In 2009, worldwide sales of Li-ion batteries for these applications alone were US$ 7 billion. Furthermore, their performance characteristics (Figure 1) make them attractive for traction applications such as

  20. Fabrication of supported Ca-doped lanthanum niobate electrolyte layer and NiO containing anode functional layer by electrophoretic deposition

    DEFF Research Database (Denmark)

    Bozza, Francesco; Bonanos, Nikolaos

    2012-01-01

    The technique of electrophoretic deposition (EPD) has been applied for the preparation of a dense calcium-doped lanthanum niobate electrolyte film. La0.995Ca0.005NbO4 (LCN) powder was suspended in a solution of acetylacetone, iodine and water. The effects of suspension composition and deposition...

  1. High Performance Fe-Co Based SOFC Cathodes

    DEFF Research Database (Denmark)

    Kammer Hansen, Kent; Hansen, Karin Vels; Mogensen, Mogens Bjerg

    2010-01-01

    With the aim of reducing the temperature of the solid oxide fuel cell (SOFC), a new high-performance perovskite cathode has been developed. An area-specific resistance (ASR) as low as 0.12 Ωcm2 at 600 °C was measured by electrochemical impedance spectroscopy (EIS) on symmetrical cells. The cathode...... is a composite between (Gd0.6Sr0.4)0.99Fe0.8Co0.2O3-δ (GSFC) and Ce0.9Gd0.1O1.95 (CGO10). Examination of the microstructure of the cathodes by scanning electron microscopy (SEM) revealed a possibility of further optimisation of the microstructure in order to increase the performance of the cathodes. It also...... seems that an adjustment of the sintering temperature will make a lowering of the ASR value possible. The cathodes were compatible with ceria-based electrolytes but reacted to some extent with zirconia-based electrolytes depending on the sintering temperature....

  2. Pt–Au/C cathode with enhanced oxygen-reduction activity in PEFCs

    Indian Academy of Sciences (India)

    G Selvarani; S Vinod Selvaganesh; P Sridhar; S Pitchumani; A K Shukla

    2011-04-01

    Carbon-supported Pt–Au (Pt–Au/C) catalyst is prepared separately by impregnation, colloidal and micro-emulsion methods, and characterized by physical and electrochemical methods. Highest catalytic activity towards oxygen-reduction reaction (ORR) is exhibited by Pt–Au/C catalyst prepared by colloidal method. The optimum atomic ratio of Pt to Au in Pt–Au/C catalyst prepared by colloidal method is determined using linear-sweep and cyclic voltammetry in conjunction with cell-polarization studies. Among 3:1, 2:1 and 1:1 Pt–Au/C catalysts, (3:1) Pt–Au/C exhibits maximum electrochemical activity towards ORR. Powder X-ray diffraction pattern and transmission electron micrograph suggest Pt–Au alloy nanoparticles to be well dispersed onto the carbon-support. Energy dispersive X-ray analysis and inductively coupled plasma-optical emission spectroscopy data suggest that the atomic ratios of the alloying elements match well with the expected values. A polymer electrolyte fuel cell (PEFC) operating at 0.6 V with (3:1) Pt–Au/C cathode delivers a maximum power-density of 0.65 W/cm2 in relation to 0.53 W/cm2 delivered by the PEFC with pristine carbon-supported Pt cathode.

  3. Anisotropic etching of platinum electrodes at the onset of cathodic corrosion.

    Science.gov (United States)

    Hersbach, Thomas J P; Yanson, Alexei I; Koper, Marc T M

    2016-08-24

    Cathodic corrosion is a process that etches metal electrodes under cathodic polarization. This process is presumed to occur through anionic metallic reaction intermediates, but the exact nature of these intermediates and the onset potential of their formation is unknown. Here we determine the onset potential of cathodic corrosion on platinum electrodes. Electrodes are characterized electrochemically before and after cathodic polarization in 10 M sodium hydroxide, revealing that changes in the electrode surface start at an electrode potential of -1.3 V versus the normal hydrogen electrode. The value of this onset potential rules out previous hypotheses regarding the nature of cathodic corrosion. Scanning electron microscopy shows the formation of well-defined etch pits with a specific orientation, which match the voltammetric data and indicate a remarkable anisotropy in the cathodic etching process, favouring the creation of (100) sites. Such anisotropy is hypothesized to be due to surface charge-induced adsorption of electrolyte cations.

  4. Cathodic delamination: Quantification of ionic transport rates along coating-steel interfaces

    DEFF Research Database (Denmark)

    Sørensen, P.A.; Dam-Johansen, Kim; Weinell, C.E.

    2010-01-01

    So-called cathodic delamination is one of the major modes of failure for organic coatings immersed in electrolyte solutions (e.g. seawater). Cathodic delamination occurs as a result of the electrochemical reactions, which takes place on a corroding steel surface. This means that reactants must...... continuously be transported from the bulk solution to the cathodic areas. The transport of sodium ions from a defect in the coating to the cathodic areas is generally considered the rate-determining step for cathodic delamination because the transport of oxygen and water through the coating is sufficient...... and Fick's second law, under the assumption of a transport-controlled mechanism, show qualitative agreement with the observed delamination rates in 0.5 M sodium chloride. This confirms that the rate-determining step of cathodic delamination is the transport of sodium ions along the coating-steel interface....

  5. Cathodic delamination: Quantification of ionic transport rates along coating-steel interfaces

    DEFF Research Database (Denmark)

    Sørensen, Per Aggerholm; Dam-Johansen, Kim; Weinell, C. E.

    2010-01-01

    So-called cathodic delamination is one of the major modes of failure for organic coatings immersed in electrolyte solutions (e.g. seawater). Cathodic delamination occurs as a result of the electrochemical reactions. which takes place on a corroding steel surface. This means that reactants must...... continuously be transported from the bulk solution to the cathodic areas. The transport of sodium ions from a defect in the coating to the cathodic areas is generally considered the rate-determining step for cathodic delamination because the transport of oxygen and water through the coating is sufficient...... and Fick's second law, under the assumption of a transport controlled mechanism, show qualitative agreement with the observed delamination rates in 0.5 M sodium chloride. This confirms that the rate-determining step of cathodic delamination is the transport of sodium ions along the coating-steel interface...

  6. Polyamidoamine dendrimer-based binders for high-loading lithium–sulfur battery cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharya, Priyanka; Nandasiri, Manjula I.; Lv, Dongping; Schwarz, Ashleigh M.; Darsell, Jens T.; Henderson, Wesley A.; Tomalia, Donald A.; Liu, Jun; Zhang, Ji-Guang; Xiao, Jie

    2016-01-01

    Lithium-sulfur (Li-S) batteries are regarded as one of the most promising candidates for next generation energy storage systems because of their ultra high theoretical specific energy. To realize the practical application of Li-S batteries, however, a high S active material loading is essential (>70 wt% in the carbon-sulfur (C-S) composite cathode and >2 mg cm-2 in the electrode). A critical challenge to achieving this high capacity in practical electrodes is the dissolution of the longer lithium polysulfide reaction intermediates in the electrolyte (resulting in loss of active material from the cathode and contamination of the anode due to the polysulfide shuttle mechanism). The binder material used for the cathode is therefore crucial as this is a key determinant of the bonding interactions between the active material (S) and electronic conducting support (C), as well as the maintenance of intimate contact between the electrode materials and current collector. The battery performance can thus be directly correlated with the choice of binder, but this has received only minimal attention in the relevant Li-S battery published literature. Here, we investigated the application of polyamidoamine (PAMAM) dendrimers as functional binders in Li-S batteries—a class of materials which has been unexplored for electrode design. By using dendrimers, it is demonstrated that high S loadings (>4 mg cm-2) can be easily achieved using "standard" (not specifically tailored) materials and simple processing methods. An exceptional electrochemical cycling performance was obtained (as compared to cathodes with conventional linear polymeric binders such as carboxymethyl cellulose (CMC) and styrene-butadiene rubber (SBR)) with >100 cycles and 85-98% capacity retention, thus demonstrating the significant utility of this new binder architecture which exhibits critical physicochemical properties and flexible nanoscale design parameters (CNDP's).

  7. Cathodes for Solid Oxide Fuel Cells Operating at Low Temperatures

    DEFF Research Database (Denmark)

    Samson, Alfred Junio

    This dissertation focuses on the development of nanostructured cathodes for solid oxide fuel cells (SOFCs) and their performance at low operating temperatures. Cathodes were mainly fabricated by the infiltration method, whereby electrocatalysts are introduced onto porous, ionic conducting backbones......degreeC. The most promising cathode was integrated onto an anode supported cell and it was found that the cell exhibits electrochemical stability with no measureable degradation during 1500 h operation at 700degreeC. LaCoO3 and Co3O4 infiltrated - CGO cathodes were also investigated and revealed...

  8. Cathodic electrocatalyst layer for electrochemical generation of hydrogen peroxide

    Science.gov (United States)

    Rhodes, Christopher P. (Inventor); Tennakoon, Charles L. K. (Inventor); Singh, Waheguru Pal (Inventor); Anderson, Kelvin C. (Inventor)

    2011-01-01

    A cathodic gas diffusion electrode for the electrochemical production of aqueous hydrogen peroxide solutions. The cathodic gas diffusion electrode comprises an electrically conductive gas diffusion substrate and a cathodic electrocatalyst layer supported on the gas diffusion substrate. A novel cathodic electrocatalyst layer comprises a cathodic electrocatalyst, a substantially water-insoluble quaternary ammonium compound, a fluorocarbon polymer hydrophobic agent and binder, and a perfluoronated sulphonic acid polymer. An electrochemical cell using the novel cathodic electrocatalyst layer has been shown to produce an aqueous solution having between 8 and 14 weight percent hydrogen peroxide. Furthermore, such electrochemical cells have shown stable production of hydrogen peroxide solutions over 1000 hours of operation including numerous system shutdowns.

  9. RAYLEIGH WAVE STUDIES OF CATHODIC H-CHARGING OF Fe

    OpenAIRE

    Lunarska, E.; Fiore, N.

    1981-01-01

    The attenuation of 2-6 MHz Rayleigh waves /RW/ was measured in sheet samples of Fe which were undergoing electrolytic charging with H. The cathodic polarization and As2O3 addition into electrolyte were found to effect the attenuation and velocity of the surface waves. The attenuation changes were retarded by the deposition of a thin /2µm/ layer of Cu on the Fe surface, with the Cu acting as a H-permeation barrier. The decrease in attenuation was caused by the entry of H into solid solution at...

  10. Nanostructured sulfur cathodes

    KAUST Repository

    Yang, Yuan

    2013-01-01

    Rechargeable Li/S batteries have attracted significant attention lately due to their high specific energy and low cost. They are promising candidates for applications, including portable electronics, electric vehicles and grid-level energy storage. However, poor cycle life and low power capability are major technical obstacles. Various nanostructured sulfur cathodes have been developed to address these issues, as they provide greater resistance to pulverization, faster reaction kinetics and better trapping of soluble polysulfides. In this review, recent developments on nanostructured sulfur cathodes and mechanisms behind their operation are presented and discussed. Moreover, progress on novel characterization of sulfur cathodes is also summarized, as it has deepened the understanding of sulfur cathodes and will guide further rational design of sulfur electrodes. © 2013 The Royal Society of Chemistry.

  11. Sulfur-impregnated disordered carbon nanotubes cathode for lithium-sulfur batteries.

    Science.gov (United States)

    Guo, Juchen; Xu, Yunhua; Wang, Chunsheng

    2011-10-12

    The commercialization of lithium-sulfur batteries is hindered by low cycle stability and low efficiency, which are induced by sulfur active material loss and polysulfide shuttle reaction through dissolution into electrolyte. In this study, sulfur-impregnated disordered carbon nanotubes are synthesized as cathode material for the lithium-sulfur battery. The obtained sulfur-carbon tube cathodes demonstrate superior cyclability and Coulombic efficiency. More importantly, the electrochemical characterization indicates a new stabilization mechanism of sulfur in carbon induced by heat treatment.

  12. Catalytic Surface Promotion of Composite Cathodes in Protonic Ceramic Fuel Cells

    DEFF Research Database (Denmark)

    Solis, Cecilia; Navarrete, Laura; Bozza, Francesco;

    2015-01-01

    Composite cathodes based on an electronic conductor and a protonic conductor show advantages for protonic ceramic fuel cells. In this work, the performance of a La5.5WO11.25-δ/ La0.8Sr0.2MnO3+δ (LWO/LSM) composite cathode in a fuel cell based on an LWO protonic conducting electrolyte is shown and...

  13. Direct observation of the oxygenated species during oxygen reduction on a platinum fuel cell cathode

    OpenAIRE

    Kaya, Sarp; Casalongue, Hernan Sanchez; Viswanathan, Venkatasubramanian ; Miller, Daniel J. ; Friebel, Daniel ; Hansen, Heine A. ; Nørskov, Jens K. ; Nilsson, Anders ; Ogasawara, Hirohito

    2013-01-01

    The performance of polymer electrolyte membrane fuel cells is limited by the reduction at the cathode of various oxygenated intermediates in the four-electron pathway of the oxygen reduction reaction. Here we use ambient pressure X-ray photoelectron spectroscopy, and directly probe the correlation between the adsorbed species on the surface and the electrochemical potential. We demonstrate that, during the oxygen reduction reaction, hydroxyl intermediates on the cathode surface occur in sever...

  14. Cathodic hydrodimerization of nitroolefins

    OpenAIRE

    Michael Weßling; Hans J. Schäfer

    2015-01-01

    Nitroalkenes are easily accessible in high variety by condensation of aldehydes with aliphatic nitroalkanes. They belong to the group of activated alkenes that can be hydrodimerized by cathodic reduction. There are many olefins with different electron withdrawing groups used for cathodic hydrodimerization, but not much is known about the behaviour of the nitro group. Synthetic applications of this group could profit from the easy access to nitroolefins in large variety, the C–C bond formation...

  15. Effect of cathode gas humidification on performance and durability of Solid Oxide Fuel Cells

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Hagen, Anke; Liu, Yi-Lin

    2010-01-01

    The effect of cathode inlet gas humidification was studied on single anode supported Solid Oxide Fuel Cells (SOFC's). The studied cells were Risø 2 G and 2.5 G. The former consists of a LSM:YSZ composite cathode, while the latter consists of a LSCF:CGO composite cathode on a CGO protection layer...

  16. A solid-polymer-electrolyte direct methanol fuel cell (DMFC) with Pt-Ru nanoparticles supported onto poly(3,4-ethylenedioxythiophene) and polystyrene sulphonic acid polymer composite as anode

    Indian Academy of Sciences (India)

    K K Tintula; S Pitchumani; P Sridhar; A K Shukla

    2010-05-01

    Nano-sized Pt-Ru supported onto a mixed-conducting polymer composite comprising poly(3,4-ethylenedioxythiophene)-polystyrene sulphonic acid (PEDOT-PSSA) is employed as anode in a solid-polymer-electrolyte direct methanol fuel cell (SPE-DMFC) and its performance compared with the SPE-DMFC employing conventional Vulcan XC-72R carbon supported Pt-Ru anode. Physical characterization of the catalyst is conducted by Fourier-transform infra-red (FTIR) spectroscopy, X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Energy dispersive X-ray analysis (EDAX) in conjunction with cyclic voltammetry and chronoamperometry. The study suggests that PEDOT-PSSA to be a promising alternative catalyst-support-material for SPE-DMFCs.

  17. Temporal variations of cathode performance in air-cathode single-chamber microbial fuel cells with different separators

    Science.gov (United States)

    Ma, Jinxing; Wang, Zhiwei; Suor, Denis; Liu, Shumeng; Li, Jiaqi; Wu, Zhichao

    2014-12-01

    An ideal separator is essential for efficient power production from air-cathode single-chamber microbial fuel cells (MFCs). In this study, we use different kinds of membranes as separators, including Nafion 117 proton exchange membrane, polyethersulfone and poly(vinylidene fluoride) microfiltration membranes. Temporal variations of cathode performance are monitored during the experiment. Results show that MFCs with microfiltration membranes present higher power output but deterioration is still observed after about 600-h operation. With the utilization of appropriate separators (e.g., polyethersulfone membrane), biofouling, cation fouling and chemical scale fouling of the cathodes are alleviated while reaction fouling seems inevitable. Moreover, it is found that Coulombic efficiency (CE) and energy efficiency (EE) are also related to the cathode performance. Despite relatively high oxygen diffusivity (1.49 × 10-5 cm2 s-1), CE and EE of the MFC with 0.1 μm pore-size polyethersulfone membrane can reach 92.8% and 13.7%, respectively, when its average power density registers 403.5 mW m-2. This phenomenon might be attributed to the finding that the overall substrate consumption rate due to oxygen reduction and respiration is almost constant in the air-cathode MFCs. Oxygen leakage into the electrolyte can be inhibited due to the efficient oxygen reduction reaction on the surface of the cathode.

  18. Electrolytes for Use in High Energy Lithium-Ion Batteries with Wide Operating Temperature Range

    Science.gov (United States)

    Smart, Marshall C.; Ratnakumar, B. V.; West, W. C.; Whitcanack, L. D.; Huang, C.; Soler, J.; Krause, F. C.

    2011-01-01

    Objectives of this work are: (1) Develop advanced Li -ion electrolytes that enable cell operation over a wide temperature range (i.e., -30 to +60C). (2) Improve the high temperature stability and lifetime characteristics of wide operating temperature electrolytes. (3) Improve the high voltage stability of these candidate electrolytes systems to enable operation up to 5V with high specific energy cathode materials. (4) Define the performance limitations at low and high temperature extremes, as well as, life limiting processes. (5) Demonstrate the performance of advanced electrolytes in large capacity prototype cells.

  19. Impact resistant electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Veith, Gabriel M.; Armstrong, Beth L.; Tenhaeff, Wyatt E.; Dudney, Nancy J.

    2017-03-07

    A passively impact resistant composite electrolyte composition includes an electrolyte solvent, up to 2M of an electrolyte salt, and shear thickening ceramic particles having a polydispersity index of no greater than 0.1, an average particle size of in a range of 50 nm to 1 .mu.m, and an absolute zeta potential of greater than .+-.40 mV.

  20. Improving the electrolyte-cathode assembly for MT-SOFC

    NARCIS (Netherlands)

    Hildenbrand, Nicolas

    2011-01-01

    In the long road towards commercialization of Solid Oxide Fuel Cells, improving the cathode’s performance is a major milestone. Achieving low Area Specific Resistances at temperatures around 600 °C are required to meet the market demands in terms of costs and lifetime. In this thesis, different res

  1. Lithium Polymer Electrolyte Battery, Electrochemical Behavior of Cathode Materials

    Science.gov (United States)

    1989-06-15

    National Meeting of the Electrochemical Society , Hollywood, Florida, 1989 Corrosion Research Center Department of Chemical Engineering and Materials...88 TO 6/89 89/06/15 16. SUPPLEMENTARY NOTATION 176th Meeting of the Electrochemical Society , Extended Abstracts, October 1989 17 COSA7I CODES 18

  2. Improved cathode materials for microbial electrosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, T; Nie, HR; Bain, TS; Lu, HY; Cui, MM; Snoeyenbos-West, OL; Franks, AE; Nevin, KP; Russell, TP; Lovley, DR

    2013-01-01

    Microbial electrosynthesis is a promising strategy for the microbial conversion of carbon dioxide to transportation fuels and other organic commodities, but optimization of this process is required for commercialization. Cathodes which enhance electrode-microbe electron transfer might improve rates of product formation. To evaluate this possibility, biofilms of Sporomusa ovata, which are effective in acetate electrosynthesis, were grown on a range of cathode materials and acetate production was monitored over time. Modifications of carbon cloth that resulted in a positive-charge enhanced microbial electrosynthesis. Functionalization with chitosan or cyanuric chloride increased acetate production rates 6-7 fold and modification with 3-aminopropyltriethoxysilane gave rates 3-fold higher than untreated controls. A 3-fold increase in electrosynthesis over untreated carbon cloth cathodes was also achieved with polyaniline cathodes. However, not all strategies to provide positively charged surfaces were successful, as treatment of carbon cloth with melamine or ammonia gas did not stimulate acetate electrosynthesis. Treating carbon cloth with metal, in particular gold, palladium, or nickel nanoparticles, also promoted electrosynthesis, yielding electrosynthesis rates that were 6-,4.7- or 4.5-fold faster than the untreated control, respectively. Cathodes comprised of cotton or polyester fabric treated with carbon nanotubes yielded cathodes that supported acetate electrosynthesis rates that were similar to 3-fold higher than carbon cloth controls. Recovery of electrons consumed in acetate was similar to 80% for all materials. The results demonstrate that one approach to increase rates of carbon dioxide reduction in microbial electrosynthesis is to modify cathode surfaces to improve microbe-electrode interactions.

  3. Progress in Electrolyte-Free Fuel Cells

    Directory of Open Access Journals (Sweden)

    Yuzheng eLu

    2016-05-01

    Full Text Available Solid Oxide Fuel Cell (SOFC represents a clean electrochemical energy conversion technology with characteristics of high conversion efficiency and low emissions. It is one of the most important new energy technologies in the future. However, the manufacture of SOFCs based on the structure of anode/electrolyte/cathode is complicated and time-consuming. Thus, the cost for the entire fabrication and technology is too high to be affordable and challenges still hinder commercialization. Recently, a novel type of Electrolyte -free fuel cell (EFFC with single component was invented which could be the potential candidate for the next generation of advanced fuel cells. This paper briefly introduces the EFFC, working principle, performance and advantages with updated research progress. A number of key R&D issues about EFFCs have been addressed and future opportunities and challenges are discussed.

  4. Fuel cells with doped lanthanum gallate electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Feng Man [Texas Univ., Austin, TX (United States). Center for Materials Science and Engineering; Goodenough, J.B. [Texas Univ., Austin, TX (United States). Center for Materials Science and Engineering; Huang Keqin [Texas Univ., Austin, TX (United States). Center for Materials Science and Engineering; Milliken, C. [Cerematec, Inc., Salt Lake City, UT (United States)

    1996-11-01

    Single cells with doped lanthanum gallate electrolyte material were constructed and tested from 600 to 800 C. Both ceria and the electrolyte material were mixed with NiO powder respectively to form composite anodes. Doped lanthanum cobaltite was used exclusively as the cathode material. While high power density from the solid oxide fuel cells at 800 C was achieved, our results clearly indicate that anode overpotential is the dominant factor in the power loss of the cells. Better anode materials and anode processing methods need to be found to fully utilize the high ionic conductivity of the doped lanthanum gallate and achieve higher power density at 800 C from solid oxide fuel cells. (orig.)

  5. Advances in primary lithium liquid cathode batteries

    Science.gov (United States)

    Blomgren, George E.

    1989-05-01

    Recent work on cell development and various aspects of cell chemistry and cell development of lithium/thionyl chloride liquid cathode batteries is reviewed. As a result of safety studies, a number of cell sizes can now be considered satisfactory for many applications and the energy densities of these cells is higher than any other developed battery system. Primary batteries operate with low to moderate currents and the anode delay effect appears to be under reasonable control. Reserve cells are in the design stage and operate at high to very high power densities as well as very high energy densities. The nature of the anode film and the operation of the lithium anode has been studied with substantial success and understanding has grown accordingly. Also, studies of the structure of the electrolyte and the effects on the electrolyte of impurities and additives have led to improved understanding in this area as well. Work in progress on new electrolytes is reviewed. The state of the art of mathematical modeling is also discussed and it is expected that this work will continue to develop.

  6. Nanoporous polymer electrolyte

    Science.gov (United States)

    Elliott, Brian [Wheat Ridge, CO; Nguyen, Vinh [Wheat Ridge, CO

    2012-04-24

    A nanoporous polymer electrolyte and methods for making the polymer electrolyte are disclosed. The polymer electrolyte comprises a crosslinked self-assembly of a polymerizable salt surfactant, wherein the crosslinked self-assembly includes nanopores and wherein the crosslinked self-assembly has a conductivity of at least 1.0.times.10.sup.-6 S/cm at 25.degree. C. The method of making a polymer electrolyte comprises providing a polymerizable salt surfactant. The method further comprises crosslinking the polymerizable salt surfactant to form a nanoporous polymer electrolyte.

  7. Improved electrolytes for Li-ion batteries: Mixtures of ionic liquid and organic electrolyte with enhanced safety and electrochemical performance

    Energy Technology Data Exchange (ETDEWEB)

    Guerfi, A.; Dontigny, M.; Charest, P.; Petitclerc, M.; Lagace, M.; Vijh, A.; Zaghib, K. [Institut de Recherche d' Hydro-Quebec, 1800 Lionel Boulet, Varennes, QC J3X 1S1 (Canada)

    2010-02-01

    Physical and electrochemical characteristics of Li-ion battery systems based on LiFePO{sub 4} cathodes and graphite anodes with mixture electrolytes were investigated. The mixed electrolytes are based on an ionic liquid (IL), and organic solvents used in commercial batteries. We investigated a range of compositions to determine an optimum conductivity and non-flammability of the mixed electrolyte. This led us to examine mixtures of ILs with the organic electrolyte usually employed in commercial Li-ion batteries, i.e., ethylene carbonate (EC) and diethylene carbonate (DEC). The IL electrolyte consisted of (trifluoromethyl sulfonylimide) (TFSI) as anion and 1-ethyl-3-methyleimidazolium (EMI) as the cation. The physical and electrochemical properties of some of these mixtures showed an improvement characteristics compared to the constituents alone. The safety was improved with electrolyte mixtures; when IL content in the mixture is {>=}40%, no flammability is observed. A stable SEI layer was obtained on the MCMB graphite anode in these mixed electrolytes, which is not obtained with IL containing the TFSI-anion. The high-rate capability of LiFePO{sub 4} is similar in the organic electrolyte and the mixture with a composition of 1:1. The interface resistance of the LiFePO{sub 4} cathode is stabilized when the IL is added to the electrolyte. A reversible capacity of 155 mAh g{sup -1} at C/12 is obtained with cells having at least some organic electrolyte compared to only 124 mAh g{sup -1} with pure IL. With increasing discharge rate, the capacity is maintained close to that in the organic solvent up to 2 C rate. At higher rates, the results with mixture electrolytes start to deviate from the pure organic electrolyte cell. The evaluation of the Li-ion cells; LiFePO{sub 4}//Li{sub 4}Ti{sub 5}O{sub 12} with organic and, 40% mixture electrolytes showed good 1st CE at 98.7 and 93.0%, respectively. The power performance of both cell configurations is comparable up to 2 C rate

  8. Improved electrolytes for Li-ion batteries: Mixtures of ionic liquid and organic electrolyte with enhanced safety and electrochemical performance

    Science.gov (United States)

    Guerfi, A.; Dontigny, M.; Charest, P.; Petitclerc, M.; Lagacé, M.; Vijh, A.; Zaghib, K.

    Physical and electrochemical characteristics of Li-ion battery systems based on LiFePO 4 cathodes and graphite anodes with mixture electrolytes were investigated. The mixed electrolytes are based on an ionic liquid (IL), and organic solvents used in commercial batteries. We investigated a range of compositions to determine an optimum conductivity and non-flammability of the mixed electrolyte. This led us to examine mixtures of ILs with the organic electrolyte usually employed in commercial Li-ion batteries, i.e., ethylene carbonate (EC) and diethylene carbonate (DEC). The IL electrolyte consisted of (trifluoromethyl sulfonylimide) (TFSI) as anion and 1-ethyl-3-methyleimidazolium (EMI) as the cation. The physical and electrochemical properties of some of these mixtures showed an improvement characteristics compared to the constituents alone. The safety was improved with electrolyte mixtures; when IL content in the mixture is ≥40%, no flammability is observed. A stable SEI layer was obtained on the MCMB graphite anode in these mixed electrolytes, which is not obtained with IL containing the TFSI-anion. The high-rate capability of LiFePO 4 is similar in the organic electrolyte and the mixture with a composition of 1:1. The interface resistance of the LiFePO 4 cathode is stabilized when the IL is added to the electrolyte. A reversible capacity of 155 mAh g -1 at C/12 is obtained with cells having at least some organic electrolyte compared to only 124 mAh g -1 with pure IL. With increasing discharge rate, the capacity is maintained close to that in the organic solvent up to 2 C rate. At higher rates, the results with mixture electrolytes start to deviate from the pure organic electrolyte cell. The evaluation of the Li-ion cells; LiFePO 4//Li 4Ti 5O 12 with organic and, 40% mixture electrolytes showed good 1st CE at 98.7 and 93.0%, respectively. The power performance of both cell configurations is comparable up to 2 C rate. This study indicates that safety and

  9. Direct regeneration of recycled cathode material mixture from scrapped LiFePO4 batteries

    Science.gov (United States)

    Li, Xuelei; Zhang, Jin; Song, Dawei; Song, Jishun; Zhang, Lianqi

    2017-03-01

    A new green recycling process (named as direct regeneration process) of cathode material mixture from scrapped LiFePO4 batteries is designed for the first time. Through this direct regeneration process, high purity cathode material mixture (LiFePO4 + acetylene black), anode material mixture (graphite + acetylene black) and other by-products (shell, Al foil, Cu foil and electrolyte solvent, etc.) are recycled from scrapped LiFePO4 batteries with high yield. Subsequently, recycled cathode material mixture without acid leaching is further directly regenerated with Li2CO3. Direct regeneration procedure of recycled cathode material mixture from 600 to 800 °C is investigated in detail. Cathode material mixture regenerated at 650 °C display excellent physical, chemical and electrochemical performances, which meet the reuse requirement for middle-end Li-ion batteries. The results indicate the green direct regeneration process with low-cost and high added-value is feasible.

  10. 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.

  11. Water balance simulations of a polymer-electrolyte membrane fuel cell using a two-fluid model

    DEFF Research Database (Denmark)

    Berning, Torsten; Odgaard, M.; Kær, Søren Knudsen

    2011-01-01

    A previously published computational multi-phase model of a polymer-electrolyte membrane fuel cell cathode has been extended in order to account for the anode side and the electrolyte membrane. The model has been applied to study the water balance of a fuel cell during operation under various...... humidification conditions. It was found that the specific surface area of the electrolyte in the catalyst layers close to the membrane is of critical importance for the overall water balance. Applying a high specific electrolyte surface area close to the membrane (a water-uptake layer) can prevent drying out...... of the anode and flooding at the cathode while the average membrane water content is only weakly affected. The results also indicate that in contrast to common presumption membrane dehydration may occur at either anode or cathode side, entirely depending on the direction of the net water transport because...

  12. Filtered cathodic arc source

    Science.gov (United States)

    Falabella, Steven; Sanders, David M.

    1994-01-01

    A continuous, cathodic arc ion source coupled to a macro-particle filter capable of separation or elimination of macro-particles from the ion flux produced by cathodic arc discharge. The ion source employs an axial magnetic field on a cathode (target) having tapered sides to confine the arc, thereby providing high target material utilization. A bent magnetic field is used to guide the metal ions from the target to the part to be coated. The macro-particle filter consists of two straight solenoids, end to end, but placed at 45.degree. to one another, which prevents line-of-sight from the arc spot on the target to the parts to be coated, yet provides a path for ions and electrons to flow, and includes a series of baffles for trapping the macro-particles.

  13. Highly Efficient Micro Cathode Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Busek Company, Inc. proposes to develop a micro thermionic cathode that requires extremely low power and provides long lifetime. The basis for the cathode is a...

  14. Advanced Cathode Electrolyzer (ACE) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed innovation is a static, cathode-fed, 2000 psi, balanced-pressure Advanced Cathode Electrolyzer (ACE) based on PEM electrolysis technology. It...

  15. All-solid-state proton battery using gel polymer electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, Kuldeep, E-mail: mishkuldeep@gmail.com [Department of Applied Science and Humanities, ABES Engineering College, Ghaziabad-201009, India and Department of Physics and Materials Science and Engineering, Jaypee Institute of Information Technology, Noida-201307 (India); Pundir, S. S.; Rai, D. K. [Department of Physics and Materials Science and Engineering, Jaypee Institute of Information Technology, Noida-201307 (India)

    2014-04-24

    A proton conducting gel polymer electrolyte system; PMMA+NH{sub 4}SCN+EC/PC, has been prepared. The highest ionic conductivity obtained from the system is 2.5 × 10−4 S cm{sup −1}. The optimized composition of the gel electrolyte has been used to fabricate a proton battery with Zn/ZnSO{sub 4}⋅7H{sub 2}O anode and MnO{sub 2} cathode. The open circuit voltage of the battery is 1.4 V and the highest energy density is 5.7 W h kg−1 for low current drain.

  16. Electrolytic coloration of hydroxyl-doped potassium iodide polycrystals

    Science.gov (United States)

    Wang, Na; Gu, Hongen; Han, Li; Guo, Meili; Qin, Fang

    2007-03-01

    Hydroxyl-doped potassium iodide polycrystals were successfully colored electrolytically by using a pointed cathode and a flat anode at various temperatures and electric field strengths, which mainly benefits appropriate coloration temperatures and electric field strengths. Characteristic OH-, O2--Va+ , U, V2, V3, Cu+, Cu-related, I2- , I2, K, F, R1 and R2 spectral bands were observed in Kubelka-Munk functions of the colored polycrystals, and the OH- and O2--Va+ spectral bands at room temperature were determined from Mollwo-Ivey plots. Color center formation in the electrolytic coloration was explained.

  17. Miniaturized cathodic arc plasma source

    Science.gov (United States)

    Anders, Andre; MacGill, Robert A.

    2003-04-15

    A cathodic arc plasma source has an anode formed of a plurality of spaced baffles which extend beyond the active cathode surface of the cathode. With the open baffle structure of the anode, most macroparticles pass through the gaps between the baffles and reflect off the baffles out of the plasma stream that enters a filter. Thus the anode not only has an electrical function but serves as a prefilter. The cathode has a small diameter, e.g. a rod of about 1/4 inch (6.25 mm) diameter. Thus the plasma source output is well localized, even with cathode spot movement which is limited in area, so that it effectively couples into a miniaturized filter. With a small area cathode, the material eroded from the cathode needs to be replaced to maintain plasma production. Therefore, the source includes a cathode advancement or feed mechanism coupled to cathode rod. The cathode also requires a cooling mechanism. The movable cathode rod is housed in a cooled metal shield or tube which serves as both a current conductor, thus reducing ohmic heat produced in the cathode, and as the heat sink for heat generated at or near the cathode. Cooling of the cathode housing tube is done by contact with coolant at a place remote from the active cathode surface. The source is operated in pulsed mode at relatively high currents, about 1 kA. The high arc current can also be used to operate the magnetic filter. A cathodic arc plasma deposition system using this source can be used for the deposition of ultrathin amorphous hard carbon (a-C) films for the magnetic storage industry.

  18. Lithium-ferrate-based cathodes for molten carbonate fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Lanagan, M.T.; Bloom, I.; Kaun, T.D. [Argonne National Lab., IL (United States)] [and others

    1996-12-31

    Argonne National Laboratory is developing advanced cathodes for pressurized operation of the molten carbonate fuel cell (MCFC) at {approximately}650{degrees}C. To be economically viable for stationary power generation, molten carbonate fuel cells must have lifetimes of more than 25,000 h while exhibiting superior cell performance. In the present technology, lithiated NiO is used as the cathode. Over the lifetime of the cell, however, N{sup 2+} ions tend to transport to the anode, where they are reduced to metallic Ni. With increased CO{sub 2} partial pressure, the transport of Ni increases because of the increased solubility of NiO in the carbonate electrolyte. Although this process is slow in MCFCs operated at 1 atm and a low CO{sub 2} partial pressure (about 0.1 atm), transport of nickel to the anode may be excessive at a higher pressure (e.g., 3 atm) and a high CO{sub 2} partial pressure (e.g., about 0.3 arm). This transport is expected to lead eventually to poor MCFC performance and/or short circuiting. Several alternative cathode compositions have been explored to reduce cathode solubility in the molten salt electrolyte. For example, LiCoO{sub 2} has been studied extensively as a potential cathode material. The LiCoO{sub 2} cathode has a low resistivity, about 10-cm, and can be used as a direct substitute for NiO. Argonne is developing advanced cathodes based on lithium ferrate (LiFeO{sub 2}), which is attractive because of its very low solubility in the molten (Li,K){sub 2}CO{sub 3} electrolyte. Because of its high resistivity (about 3000-cm), however, LiFeO{sub 2} cannot be used as a direct substitute for NiO. Cation substitution is, therefore, necessary to decrease resistivity. We determined the effect of cation substitution on the resistivity and deformation of LiFeO{sub 2}. The substituents were chosen because their respective oxides as well as LiFeO{sub 2} crystallize with the rock-salt structure.

  19. Direct fabrication of metal-free hollow graphene balls with a self-supporting structure as efficient cathode catalysts of fuel cell

    Science.gov (United States)

    Lu, Yanqi; Liu, Mingda; Nie, Huagui; Gu, Cancan; Liu, Ming; Yang, Zhi; Yang, Keqin; Chen, Xi'an; Huang, Shaoming

    2016-06-01

    Despite the good progress in developing carbon catalysts for oxygen reduction reaction (ORR), the current metal-free carbon catalysts are still far from satisfactory for large-scale applications of fuel cell. Developing hollow graphene balls with a self-supporting structure is considered to be an ideal method to inhibit graphene stacking and improve their catalytic performance. Herein, we fabricated metal-free hollow graphene balls with a self-supporting structure, through using a new strategy that involves direct metal-free catalytic growth from assembly of SiO2 spheres. To our knowledge, although much researches involving the synthesis of graphene balls have been reported, investigations into the direct metal-free catalytic growth of hollow graphene balls are rare. Furthermore, the electrocatalytic performance shows that the resulting hollow graphene balls have significantly high catalytic activity. More importantly, such catalysts also possess much improved stability and better methanol tolerance in alkaline media during the ORR compared with commercial Pt/C catalysts. The outstanding performances coupled with an easy and inexpensive preparing method indicated the great potential of the hollow graphene balls with a self-supporting structure in large-scale applications of fuel cell.

  20. Cathode material for lithium batteries

    Science.gov (United States)

    Park, Sang-Ho; Amine, Khalil

    2013-07-23

    A method of manufacture an article of a cathode (positive electrode) material for lithium batteries. The cathode material is a lithium molybdenum composite transition metal oxide material and is prepared by mixing in a solid state an intermediate molybdenum composite transition metal oxide and a lithium source. The mixture is thermally treated to obtain the lithium molybdenum composite transition metal oxide cathode material.

  1. Gel-based composite polymer electrolytes with novel hierarchical mesoporous silica network for lithium batteries

    Energy Technology Data Exchange (ETDEWEB)

    Wang Xiaoliang; Cai Qiang [Department of Materials Science and Engineering, and State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing 100084 (China); Fan Lizhen [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Hua Tao; Lin Yuanhua [Department of Materials Science and Engineering, and State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing 100084 (China); Nan Cewen [Department of Materials Science and Engineering, and State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing 100084 (China)], E-mail: cwnan@tsinghua.edu.cn

    2008-11-15

    In the present work, novel gel-based composite polymer electrolytes for lithium batteries were prepared by introducing a hierarchical mesoporous silica network to the poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP)-based gel electrolytes. As compared with the PVDF-HFP-based gel electrolytes with/without conventional nano-sized silica fillers, the novel electrolytes have shown more homogeneous microstructure, higher ionic conductivity and better mechanical stability, which could be caused by the strong silica network and the effective interactions among the polymer, the liquid electrolytes and the silica. Moreover, the cell with this kind of electrolytes could achieve a discharge capacity as much as 150 mAh g{sup -1} at room temperature (LiCoO{sub 2} as the cathode active material), with high Coulomb efficiency.

  2. Gel-based composite polymer electrolytes with novel hierarchical mesoporous silica network for lithium batteries

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiao-Liang; Cai, Qiang; Hua, Tao; Lin, Yuan-Hua; Nan, Ce-Wen [Department of Materials Science and Engineering, and State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing 100084 (China); Fan, Li-Zhen [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China)

    2008-11-15

    In the present work, novel gel-based composite polymer electrolytes for lithium batteries were prepared by introducing a hierarchical mesoporous silica network to the poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP)-based gel electrolytes. As compared with the PVDF-HFP-based gel electrolytes with/without conventional nano-sized silica fillers, the novel electrolytes have shown more homogeneous microstructure, higher ionic conductivity and better mechanical stability, which could be caused by the strong silica network and the effective interactions among the polymer, the liquid electrolytes and the silica. Moreover, the cell with this kind of electrolytes could achieve a discharge capacity as much as 150 mAh g{sup -1} at room temperature (LiCoO{sub 2} as the cathode active material), with high Coulomb efficiency. (author)

  3. Influence of Electrolyte on ESR of Medium Voltage Wet Tantalum Capacitors

    Institute of Scientific and Technical Information of China (English)

    刘仲娥; 宋金荣; 陈晓静; 李忆莲; 桂娟

    2004-01-01

    In this paper, the influence of working electrolyte on high-frequency electrical performance of wet tantalum capacitors is studied. Emphasis is especially put on the study of the contribution of depolariser in reducing Equivalent Series Resistance(ESR). According to the theory of depolarization in electrochemistry and the theory of cathode capacitance of electrolytic capacitor, different kinds of depolarisers are added separately into the foregone electrolyte. Then capacitors are assembled with tantalum cores dipped with the compounded electrolytes. The best depolariser and its concentration in the whole electrolyte could be selected according to the test results of the capacitance and ESR of the capacitors. The results of our experiment show that depolariser Fe2(SO4)3 used in working electrolyte of 100 V/100 μF wet tantalum capacitors can help to obtain lower ESR and higher capacitance at frequency from 0.1 kHz to 100 kHz.

  4. Smart cathodic protection systems

    NARCIS (Netherlands)

    Polder, R.B.; Leggedoor, J.; Schuten, G.; Sajna, S.; Kranjc, A.

    2010-01-01

    Cathodic protection delivers corrosion protection in concrete structures exposed to aggressive environments, e.g. in de-icing salt and marine climates. Working lives of a large number of CP systems are at least more than 13 years and probably more than 25 years, provided a minimum level of maintenan

  5. SOFC Cathode Mechanisms

    DEFF Research Database (Denmark)

    Jacobsen, Torben; Zachau-Christiansen, Birgit; Bay, Lasse

    1996-01-01

    The transient response of SOFC oxygen cathodes shows a characteristic inductive hysteresis and correspondingly the impedance diagram combines one or two capacitive arcs with a low frequency inductive arc. These features are discussed on the basis of a three step reaction sequence taken from...

  6. Electrolytes for low temperature solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Berkel, F.P.F. van; Christie, G.M.; Heuveln, F.H. van; Huijsmans, J.P.P. [Netherlands Energy Research Foundation, Petten (Netherlands)

    1995-12-31

    Self-supported electrolytes and electrode supported electrolytes of zirconia and ceria have been developed by means of tape casting. The conductivity data of these compounds have been obtained. Cell tests with these materials were conducted in the temperature range of 600 to 800 C. Operation of SOFC within this temperature range has been shown to be feasible.

  7. Doped carbon-sulfur species nanocomposite cathode for Li--S batteries

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Donghai; Xu, Tianren; Song, Jiangxuan

    2015-12-29

    We report a heteroatom-doped carbon framework that acts both as conductive network and polysulfide immobilizer for lithium-sulfur cathodes. The doped carbon forms chemical bonding with elemental sulfur and/or sulfur compound. This can significantly inhibit the diffusion of lithium polysulfides in the electrolyte, leading to high capacity retention and high coulombic efficiency.

  8. Simulated coal-gas-fueled molten carbonate fuel cell development program. Topical report: Cathode compatibility tests

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, W.H.

    1992-07-01

    In previous work, International Fuel Cells Corporation (EFC) found interactions between molten carbonate fuel cell cathode materials being considered as replacements for the presently used nickel oxide and matrix materials. Consequently, this work was conducted to screen additional new materials for mutual compatibility. As part of this program, experiments were performed to examine the compatibility of several candidate, alternative cathode materials with the standard lithium aluminate matrix material in the presence of electrolyte at cell potentials. Initial cathode candidates were materials lithium ferrite, yttrium iron garnet, lithium manganite and doped ceria which were developed by universities, national laboratories, or contractors to DOE, EPRI, or GRI. These investigations were conducted in laboratory scale experiments. None of the materials tested can directly replace nickel oxide or indicate greater stability of cell performance than afforded by nickel oxide. Specifically: (1) no further work on niobium doped ceria is warranted; (2) cobalt migration was found in the lithium ferrite cathode tested. This could possibly lead to shorting problems similiar to those encountered with nickel oxide; (3) Possible shorting problems may also exist with the proprietary dopant in YIG; (4) lithium ferrite and YIG cathode were not single phase materials. Assessment of the chemical stability, i.e., dopant loss, was severely impeded by dissolution of these second phases in the electrolyte; and (5) Magnesium doped lithium manganite warrants further work. Electrolytes should contain Mg ions to suppress dopant loss.

  9. Novel, Solvent-Free, Single Ion-Conducting Polymer Electrolytes

    Science.gov (United States)

    2007-10-31

    the selected polymer electrolyte membrane and a LiFePO4 -based composite cathode film. The latter was prepared by blending the LiFePO4 active...following: charge Li+ + FePO4 + e LiFePO4 [1] discharge to which is associate a maximum...as separator in a Li/ LiFePO4 battery. . 1.Experimental. Calixpyrrole (CP, provided by the University of Warsaw), LiBOB (Libby) and PEO

  10. An experimental system to investigate kinetics and isotopic properties of the electrolytic metal hydride formation

    Energy Technology Data Exchange (ETDEWEB)

    Leardini, F. [Dpto. Fisica de Materiales, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain)]. E-mail: fabrice.leardini@uam.es; Bodega, J. [Dpto. Fisica de Materiales, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Fernandez, J.F. [Dpto. Fisica de Materiales, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Sanchez, C. [Dpto. Fisica de Materiales, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain)

    2005-12-08

    We present in this paper an experimental set-up based in a mass spectrometer connected to a closed electrolytic cell. Calibrations accomplished with a Pt cathode and H{sub 2}O/D{sub 2}O mixtures have shown new kinetics in galvanostatic electrolysis. These findings may be relevant in some important processes such as the hydrogen evolution reaction, isotopic separation factors or the electrolytic formation of metal hydrides.

  11. Evaluation of apatite silicates as solid oxide fuel cell electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Marrero-Lopez, D. [Dpto. de Fisica Aplicada I, Laboratorio de Materiales y Superficies (Unidad Asociada al C.S.I.C.), Universidad de Malaga, 29071 Malaga (Spain); Dpto. de Quimica Inorganica, Universidad de La Laguna, 38200 La Laguna, Tenerife (Spain); Martin-Sedeno, M.C.; Aranda, M.A.G. [Dpto. de Quimica Inorganica, Universidad Malaga, 29071 Malaga (Spain); Pena-Martinez, J. [Dpto. de Quimica Inorganica, Universidad de La Laguna, 38200 La Laguna, Tenerife (Spain); Instituto de Energias Renovables, Parque Tecnologico, Universidad de Castilla La Mancha, 02006 Albacete (Spain); Ruiz-Morales, J.C.; Nunez, P. [Dpto. de Quimica Inorganica, Universidad de La Laguna, 38200 La Laguna, Tenerife (Spain); Ramos-Barrado, J.R. [Dpto. de Fisica Aplicada I, Laboratorio de Materiales y Superficies (Unidad Asociada al C.S.I.C.), Universidad de Malaga, 29071 Malaga (Spain)

    2010-05-01

    Apatite-type silicates have been considered as promising electrolytes for Solid Oxide Fuel Cells (SOFC); however studies on the potential use of these materials in SOFC devices have received relatively little attention. The lanthanum silicate with composition La{sub 10}Si{sub 5.5}Al{sub 0.5}O{sub 26.75} has been evaluated as electrolyte with the electrode materials commonly used in SOFC, i.e. manganite, ferrite and cobaltite as cathode materials and NiO-CGO composite, chromium-manganite and Sr{sub 2}MgMoO{sub 6} as anode materials. Chemical compatibility, area-specific resistance and fuel cell studies have been performed. X-ray powder diffraction (XRPD) analysis did not reveal any trace of reaction products between the apatite electrolyte and most of the aforementioned electrode materials. However, the area-specific polarisation resistance (ASR) of these electrodes in contact with apatite electrolyte increased significantly with the sintering temperature, indicating reactivity at the electrolyte/electrode interface. On the other hand, the ASR values are significantly improved using a ceria buffer layer between the electrolyte and electrode materials to prevent reactivity. Maximum power densities of 195 and 65 mWcm{sup -2} were obtained at 850 and 700 C, respectively in H{sub 2} fuel, using an 1 mm-thick electrolyte, a NiO-Ce{sub 0.8}Gd{sub 0.2}O{sub 1.9} composite as anode and La{sub 0.6}Sr{sub 0.4}Co{sub 0.8}Fe{sub 0.2}O{sub 3-{delta}} as cathode materials. This fuel cell was tested for 100 h in 5%H{sub 2}-Ar atmosphere showing stable performance. (author)

  12. Electrolytic hydrogen fuel production with solid polymer electrolyte technology.

    Science.gov (United States)

    Titterington, W. A.; Fickett, A. P.

    1973-01-01

    A water electrolysis technology based on a solid polymer electrolyte (SPE) concept is presented for applicability to large-scale hydrogen production in a future energy system. High cell current density operation is selected for the application, and supporting cell test performance data are presented. Demonstrated cell life data are included to support the adaptability of the SPE system to large-size hydrogen generation utility plants as needed for bulk energy storage or transmission. The inherent system advantages of the acid SPE electrolysis technology are explained. System performance predictions are made through the year 2000, along with plant capital and operating cost projections.

  13. Micro-tubular solid oxide fuel cell based on a porous yttria-stabilized zirconia support.

    Science.gov (United States)

    Panthi, Dhruba; Tsutsumi, Atsushi

    2014-08-29

    Solid oxide fuel cells (SOFCs) are promising electrochemical energy conversion devices owing to their high power generation efficiency and environmentally benign operation. Micro-tubular SOFCs, which have diameters ranging from a few millimeters to the sub-millimeter scale, offer several advantages over competing SOFCs such as high volumetric power density, good endurance against thermal cycling, and flexible sealing between fuel and oxidant streams. Herein, we successfully realized a novel micro-tubular SOFC design based on a porous yttria-stabilized zirconia (YSZ) support using multi-step dip coating and co-sintering methods. The micro-tubular SOFC consisted of Ni-YSZ, YSZ, and strontium-doped lanthanum manganite (LSM)-YSZ as the anode, electrolyte, and cathode, respectively. In addition, to facilitate current collection from the anode and cathode, Ni and LSM were applied as an anode current collector and cathode current collector, respectively. Micro-crystalline cellulose was selected as a pore former to achieve better shrinkage behavior of the YSZ support so that the electrolyte layer could be densified at a co-sintering temperature of 1300 °C. The developed micro-tubular design showed a promising electrochemical performance with maximum power densities of 525, 442, and 354 mW cm(-2) at 850, 800, and 750 °C, respectively.

  14. Optimization of electrochemical dechlorination of trichloroethylene in reducing electrolytes.

    Science.gov (United States)

    Mao, Xuhui; Ciblak, Ali; Baek, Kitae; Amiri, Mohammad; Loch-Caruso, Rita; Alshawabkeh, Akram N

    2012-04-15

    Electrochemical dechlorination of trichloroethylene (TCE) in aqueous solution is investigated in a closed, liquid-recirculation system. The anodic reaction of cast iron generates ferrous species, creating a chemically reducing electrolyte (negative ORP value). The reduction of TCE on the cathode surface is enhanced under this reducing electrolyte because of the absence of electron competition. In the presence of the iron anode, the performances of different cathodes are compared in a recirculated electrolysis system. The copper foam shows superior capability for dechlorination of aqueous TCE. Electrolysis by cast iron anode and copper foam cathode is further optimized though a multivariable experimental design and analysis. The conductivity of the electrolyte is identified as an important factor for both final elimination efficiency (FEE) of TCE and specific energy consumption. The copper foam electrode exhibits high TCE elimination efficiency in a wide range of initial TCE concentration. Under coulostatic conditions, the optimal conditions to achieve the highest FEE are 9.525 mm thick copper foam electrode, 40 mA current and 0.042 mol L(-1) Na(2)SO(4). This novel electrolysis system is proposed to remediate groundwater contaminated by chlorinated organic solvents, or as an improved iron electrocoagulation process capable of treating the wastewater co-contaminated with chlorinated compounds.

  15. Is alpha-V2O5 a cathode material for Mg insertion batteries?

    Energy Technology Data Exchange (ETDEWEB)

    Sa, Niya; Wang, Hao; Proffit, Danielle L.; Lipson, Albert L.; Key, Baris; Liu, Miao; Feng, Zhenxing; Fister, Timothy T.; Ren, Yang; Sun, Cheng-Jun; Vaughey, John T.; Fenter, Paul A.; Persson, Kristin A.; Burrell, Anthony K.

    2016-08-01

    When designing a high energy density battery, one of the critical features is a high voltage, high capacity cathode material. In the development of Mg batteries, oxide cathodes that can reversibly intercalate Mg, while at the same time being compatible with an electrolyte that can deposit Mg reversibly are rare. Herein, we report the compatibility of Mg anodes with a-V2O5 by employing magnesium bis(trifluoromethane sulfonyl)imide in diglyme electrolytes at very low water levels. Electrolytes that contain a high water level do not reversibly deposit Mg, but interestingly these electrolytes appear to enable much higher capacities for an a-V2O5 cathode. Solid state NMR indicates that the major source of the higher capacity in high water content electrolytes originates from reversible proton insertion. In contrast, we found that lowering the water level of the magnesium bis(trifluoromethane sulfonyl)imide in diglyme electrolyte is critical to achieve reversible Mg deposition and direct evidence for reversible Mg intercalation is shown. Findings we report here elucidate the role of proton intercalation in water-containing electrolytes and clarify numerous conflicting reports of Mg insertion into a-V2O5.

  16. A Fluorinated Ether Electrolyte Enabled High Performance Prelithiated Graphite/Sulfur Batteries.

    Science.gov (United States)

    Chen, Shuru; Yu, Zhaoxin; Gordin, Mikhail L; Yi, Ran; Song, Jiangxuan; Wang, Donghai

    2017-03-01

    Lithium/sulfur (Li/S) batteries have attracted great attention as a promising energy storage technology, but so far their practical applications are greatly hindered by issues of polysulfide shuttling and unstable lithium/electrolyte interface. To address these issues, a feasible strategy is to construct a rechargeable prelithiated graphite/sulfur batteries. In this work, a fluorinated ether of bis(2,2,2-trifluoroethyl) ether (BTFE) was reported to blend with 1,3-dioxolane (DOL) for making a multifunctional electrolyte of 1.0 M LiTFSI DOL/BTFE (1:1, v/v) to enable high performance prelithiated graphite/S batteries. First, the electrolyte significantly reduces polysulfide solubility to suppress the deleterious polysulfide shuttling and thus improves capacity retention of sulfur cathodes. Second, thanks to the low viscosity and good wettability, the fluorinated electrolyte dramatically enhances the reaction kinetics and sulfur utilization of high-areal-loading sulfur cathodes. More importantly, this electrolyte forms a stable solid-electrolyte interphase (SEI) layer on graphite surface and thus enables remarkable cyclability of graphite anodes. By coupling prelithiated graphite anodes with sulfur cathodes with high areal capacity of ∼3 mAh cm(-2), we demonstrate prelithiated graphite/sulfur batteries that show high sulfur-specific capacity of ∼1000 mAh g(-1) and an excellent capacity retention of >65% after 450 cycles at C/10.

  17. Sub-2 nm Thick Fluoroalkylsilane Self-Assembled Monolayer-Coated High Voltage Spinel Crystals as Promising Cathode Materials for Lithium Ion Batteries

    Science.gov (United States)

    Zettsu, Nobuyuki; Kida, Satoru; Uchida, Shuhei; Teshima, Katsuya

    2016-08-01

    We demonstrate herein that an ultra-thin fluoroalkylsilane self-assembled monolayer coating can be used as a modifying agent at LiNi0.5Mn1.5O4-δcathode/electrolyte interfaces in 5V-class lithium-ion batteries. Bare LiNi0.5Mn1.5O4-δ cathode showed substantial capacity fading, with capacity dropping to 79% of the original capacity after 100 cycles at a rate of 1C, which was entirely due to dissolution of Mn3+ from the spinel lattice via oxidative decomposition of the organic electrolyte. Capacity retention was improved to 97% on coating ultra-thin FAS17-SAM onto the LiNi0.5Mn1.5O4 cathode surface. Such surface protection with highly ordered fluoroalkyl chains insulated the cathode from direct contact with the organic electrolyte and led to increased tolerance to HF.

  18. Controllable synthesis of high loading LiFePO4/C nanocomposites using bimodal mesoporous carbon as support for high power Li-ion battery cathodes

    Institute of Scientific and Technical Information of China (English)

    Fei; Cheng; Duo; Li; Anhui; Lu; Wencui; Li

    2013-01-01

    Mesoporous LiFePO4/C composites containing 80 wt% of highly dispersed LiFePO4 nanoparticles(4-6 nm) were fabricated using bimodal mesoporous carbon(BMC) as continuous conductive networks. The unique pore structure of BMC not only promises good particle connectivity for LiFePO4, but also acts as a rigid nano-confinement support that controls the particle size. Furthermore, the capacities were investigated respectively based on the weight of LiFePO4 and the whole composite. When calculated based on the weight of the whole composite, it is 120 mAh·g-1at 0.1 C of the high loading electrode and 42 mAh·g-1at 10 C of the low loading electrode. The electrochemical performance shows that high LiFePO4 loading benefits large tap density and contributes to the energy storage at low rates, while the electrode with low content of LiFePO4 displays superior high rate performance, which can mainly be due to the small particle size, good dispersion and high utilization of the active material, thus leading to a fast ion and electron diffusion.

  19. Three-Man Solid Electrolyte Carbon Dioxide Electrolysis Breadboard

    Science.gov (United States)

    Isenberg, Arnold O.

    1989-01-01

    The development of the Three-Man (2.2 lb CO2/man-day) Solid Electrolyte CO2 Electrolysis Breadboard consisted of a Phase 1 and 2 effort. The Phase 1 effort constituted fabrication of three electrolysis cell types and performing parametric testing, off-design testing, and cell life testing. The Phase 2 consisted of the preliminary design, incorporation of palladium (Pd) tubes for hydrogen separation from the electrolyzer cathode feed gases, design support testing, final design, fabrication, and performance testing of the breadboard system. The results of performance tests demonstrated that CO2 electrolysis in an oxygen reclamation system for long duration space-based habitats is feasible. Closure of the oxygen system loop, therefore, can be achieved by CO2 electrolysis. In a two step process the metabolic CO2 and H2O vapor are electrolyzed into O2, H2, and CO. The CO can subsequently be disproportionated into carbon and CO2 in a carbon deposition reactor and the CO2 in turn be recycled and electrolyzed for total O2 recovery. The development effort demonstrated electrolyzer system can be designed and built to operate safely and reliably and the incorporation of Pd tubes for hydrogen diffusion can be integrated safely with predictable performance.

  20. A rapid one-step electrodeposition process for fabrication of superhydrobic surfaces on anode and cathode

    Institute of Scientific and Technical Information of China (English)

    郝丽梅; 闫小乐; 解忧; 张涛; 陈志

    2016-01-01

    This work presents a method to solve the weak solubility of zinc chloride (ZnCl2) in the ethanol by adding some reasonable water into an ethanol electrolyte containing ZnCl2and myristic acid (CH3(CH2)12COOH). A rapid one-step electrodeposition process was developed to fabricate anodic (2.5 min) and cathodic (40 s) superhydrophobic surfaces of copper substrate (contact angle more than 150°) in an aqueous ethanol electrolyte. Morphology, composition, chemical structure and superhydrophobicity of these superhydrophobic surfaces were investigated by SEM, FTIR, XRD, and contact angle measurement, respectively. The results indicate that water ratio of the electrolyte can reduce the required deposition time, superhydrophobic surface needs over 30 min with anhydrous electrolyte, while it needs only 2.5 min with electrolyte including 10 mL water, and the maximum contact angle of anodic surface is 166° and that of the cathodic surface is 168°. Two copper electrode surfaces have different reactions in the process of electrodeposition time, and the anodic copper surface covers copper myristate (Cu[CH3(CH2)12COO]2) and cupric chloride (CuCl); while, zinc myristate (Zn[CH3(CH2)12COO]2) and pure zinc (Zn) appear on the cathodic surface.

  1. Electrochemical generation of volatile lead species using a cadmium cathode: Comparison with graphite, glassy carbon and platinum cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Saenz, Maria; Fernandez, Lenys, E-mail: lfernandez@usb.ve; Dominguez, Jose; Alvarado, Jose

    2012-05-15

    Working electrodes made out of pyrolytic graphite, glassy carbon, platinum and cadmium were compared for the electrochemical generation of volatile lead species. The same electrolytic cell, using each of the different working electrodes was coupled to an atomic absorption spectrometer and the experimental conditions were optimized in each case, using a univariate approach, to produce the maximum possible amount of volatile lead species. The experiments were focused on the variation of cathode hydrogen overvoltage by the application of a constant current during analysis. Under optimum conditions the performance of the electrochemical hydride generator cell should depend on the cathode material selected due to the different hydrogen overpotential of each material. The lead absorbance signal was taken as a measure of the efficiency of volatile lead species production. Best results were obtained using the Cd cathode, due to its relatively highest hydrogen overpotential, a carrier gas (Ar) flow rate of 55 mL min{sup -1} an electrolytic current of 0.8 A and a catholyte (HCl) concentration 0.05 mol L{sup -1}. The analytical figures of merit of the method using the Cd electrode were evaluated and the susceptibility of the method to interferences was assessed by its application to the determination of trace amounts of lead in the presence of the most significant interferents. The calibration curve was linear between 0.5 and 15 {mu}g L{sup -1} Pb. Detection limits and characteristic mass values were 0.21 {mu}g L{sup -1} and 0.26 {mu}g L{sup -1} respectively. A bovine liver standard reference material and a spiked urine sample were analyzed to check accuracy. - Highlights: Black-Right-Pointing-Pointer Cadmium cathode for the electrochemical generation (ECHG) of lead volatile species. Black-Right-Pointing-Pointer Cadmium cathode for the ECHG of lead hydrides improve merit figures. Black-Right-Pointing-Pointer The ECHG of the volatile species depends on the hydrogen

  2. Cathodic Protection Design and Application of Offshore Wind Turbine Supporting Structure%海上风机基础阴极保护设计与应用

    Institute of Scientific and Technical Information of China (English)

    何小华; 张力

    2015-01-01

    The wind turbine foundation( WTF) is key supporting structures of wind turbines in offshore wind farm and also is impor-tant structures to ensure the normal operation of wind turbines for 25 years.WTF has characteristics of long design life, large invest-ment and high inspection and maintenance difficulty.Corrosion protection measures must be taken to make sure WTF operates nor-mally in its service life.Combined with an offshore wind farm project in the south China sea, this paper carries out research work on key link of WTF's protection, reasonable and effective design plan.%海上风机基础是海上风电场风机的重要支撑结构,也是保证风机正常运行25年的重要结构。海上风机基础具有设计寿命长、投资大、检测和维修难度高的特点,因此必须采取有效的防腐措施保证其能长效安全地服役。结合南海某海上风电工程项目,详尽地研究和论述了海上风机基础阴极保护的关键环节、合理有效的设计和布置方案,对阴极保护技术在海上风电领域的设计与应用具有一定的指导意义。

  3. Al-H2O2 Semi-fuel Cell Using Ni Foam Supported NiCo2O4 Nanowire Arrays as Cathode%以泡沫镍载NiCo2O4纳米线阵列为阴极催化剂的Al-H2O2半燃料电池

    Institute of Scientific and Technical Information of China (English)

    田永梅; 雷婷; 王贵领; 曹殿学

    2011-01-01

    研究了以泡沫镍载NiCo2O4纳米线阵列为阴极催化剂的Al-H2O2半燃料电池的性能.以无模板生长法制备了泡沫镍载NiCo2O4纳米线阵列阴极材料,SEM测定结果表明,NiCo2O4纳米线几乎垂直于泡沫镍载体表面生长.以电压和功率密度-电流密度曲线研究了H2O2浓度、电解液流速和温度对电池性能的影响,结果显示,以铝片为阳极,0.6 mol/L H2O2为氧化剂的电池的开路电压约为1.40V;在室温和57℃下,电流密度为98和172 mA/cm2时,最大功率密度分别达到79和120 mW/cm2.在5000 s的测试时间内,0.70 V的恒电流密度和75 mA/cm2的恒电压值几乎为一常数,这表明以泡沫镍载NiCo2O4纳米线阵列为催化剂电还原H2O2具有很好的活性、稳定性和传质性能.%A A1-H2O2 semi-fuel cell using Ni foam supported NiCo2O4 nanowire arrays as cathode was reported. Ni foam supported-NiCo2O4 nanowire arrays were prepared by a template-free growth method, and demonstrated that NiCo2O4 nanowires grow almost vertically from the surface of foamed Ni substrate by scanning electron microscopy (SEM). The effects of concentrations of H2O2, flow rate of electrolyte as well as operation temperature on the cell performance were investigated. The cell exhibited an open circuit voltage of about 1. 40 V; peak power densities of 79 and 120 mW/cm2 at current ensities of 98 and 172 mA/cm2 and a cell voltage of 0. 80 V and 0. 70 V operating at room temperature and 320 K, respectively, using aluminium sheet as anode fuel and 0. 6 mol/L H2O2 as oxidant. The current density at 0. 7 V and voltage 75 mA/cm2 remained nearly constant within a5000 s test period, the Ni foam supported NiCo2O4 nanowire arrays electrode exhibits superior activity, stability, and mass transport property for H2O2 electroreduction.

  4. The effect of 1,2-dimethoxyethane on the storage and performance of lithium cells with MnO 2 and (CF) n cathodes

    Science.gov (United States)

    Fr açkowiak, E.; Kuksenko, S.

    The characteristics of lithium cells with MnO 2 and (CF) n cathodes were investigated for two different electrolyte compositions, i.e., LiClO 4/PC+DME and LiClO 4/PC. For such lithium cells, the greater loss of long-term storage capacity was found in the case of cells using mixed PC+DME electrolyte. The oxidation process of DME by the cathode elements during the storage period is assumed to be the cause of the capacity loss. In the case of cells using MnO 2 as a cathode, the polymerisation process of the oxidation products of DME on the cathode surface can be also considered. After storage at 45°C, the smaller loss of capacity was found for the cells using MnO 2 as a cathode. The different behaviour of these two kinds of cells during a pulse discharge was also confirmed.

  5. Towards Prognostics of Electrolytic Capacitors

    Data.gov (United States)

    National Aeronautics and Space Administration — A remaining useful life prediction algorithm and degradation model for electrolytic capacitors is presented. Electrolytic capacitors are used in several applications...

  6. Nature of the Electrochemical Properties of Sulphur Substituted LiMn2O4 Spinel Cathode Material Studied by Electrochemical Impedance Spectroscopy

    Directory of Open Access Journals (Sweden)

    Monika Bakierska

    2016-08-01

    Full Text Available In this work, nanostructured LiMn2O4 (LMO and LiMn2O3.99S0.01 (LMOS1 spinel cathode materials were comprehensively investigated in terms of electrochemical properties. For this purpose, electrochemical impedance spectroscopy (EIS measurements as a function of state of charge (SOC were conducted on a representative charge and discharge cycle. The changes in the electrochemical performance of the stoichiometric and sulphur-substituted lithium manganese oxide spinels were examined, and suggested explanations for the observed dependencies were given. A strong influence of sulphur introduction into the spinel structure on the chemical stability and electrochemical characteristic was observed. It was demonstrated that the significant improvement in coulombic efficiency and capacity retention of lithium cell with LMOS1 active material arises from a more stable solid electrolyte interphase (SEI layer. Based on EIS studies, the Li ion diffusion coefficients in the cathodes were estimated, and the influence of sulphur on Li+ diffusivity in the spinel structure was established. The obtained results support the assumption that sulphur substitution is an effective way to promote chemical stability and the electrochemical performance of LiMn2O4 cathode material.

  7. Mercury vapor hollow cathode component studies. [emissive materials for ion thruster requirements

    Science.gov (United States)

    Zuccaro, D. E.

    1973-01-01

    An experimental study of starting and operating characteristics of conventional hollow cathodes and of hollow cathodes without alkaline earth emissive materials demonstrated that the emissive mix is essential to obtain the desired cathode operation. Loss of the emissive mix by evaporation and chemical reaction was measured. New insert designs consisting of emissive mix supported on nickel and of barium impregnated porous tungsten were studied. Cathodes with a modified orifice geometry operated in a low voltage, 'spot' mode over a broad range of discharge current. Thermal degradation tests on cathode heaters showed the flame sprayed SERT II type to be the most durable at high temperatures. Thermal shock was observed to be a significant factor in limiting cathode heater life. A cathode having a barium impregnated porous tungsten tip and a heater which is potted in sintered alumina was found to have favorable operating characteristics.

  8. Homogeneous lithium electrodeposition with pyrrolidinium-based ionic liquid electrolytes.

    Science.gov (United States)

    Grande, Lorenzo; von Zamory, Jan; Koch, Stephan L; Kalhoff, Julian; Paillard, Elie; Passerini, Stefano

    2015-03-18

    In this study, we report on the electroplating and stripping of lithium in two ionic liquid (IL) based electrolytes, namely N-butyl-N-methylpyrrolidinium bis(fluorosulfonyl) imide (Pyr14FSI) and N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (Pyr14TFSI), and mixtures thereof, both on nickel and lithium electrodes. An improved method to evaluate the Li cycling efficiency confirmed that homogeneous electroplating (and stripping) of Li is possible with TFSI-based ILs. Moreover, the presence of native surface features on lithium, directly observable via scanning electron microscope imaging, was used to demonstrate the enhanced electrolyte interphase (SEI)-forming ability, that is, fast cathodic reactivity of this class of electrolytes and the suppressed dendrite growth. Finally, the induced inhomogeneous deposition enabled us to witness the SEI cracking and revealed previously unreported bundled Li fibers below the pre-existing SEI and nonrod-shaped protuberances resulting from Li extrusion.

  9. Vertically aligned carbon nanotube-ruthenium dioxide core-shell cathode for non-aqueous lithium-oxygen batteries

    Science.gov (United States)

    Jung, C. Y.; Zhao, T. S.; Zeng, L.; Tan, P.

    2016-11-01

    Exploitation of hierarchical porous carbons is increasingly attractive for high-capacity lithium (Li)-oxygen (O2) battery cathodes. However, their practical applications in non-aqueous electrolytes are limited by poor rechargeability, primarily due to the decomposition of carbon electrode and electrolyte. In this work, we report a vertically aligned carbon nanotube (VACNT)-ruthenium dioxide (RuO2) core-shell (VACNT@RuO2) cathode for non-aqueous Li-O2 batteries. The cathode is fabricated with VACNT as the core material and hydrous RuO2 as the shell material, which eliminates the direct contact between the carbon and nucleophilic reactive intermediate species in the electrolyte. In comparison with the VACNT cathode, the VACNT@RuO2 cathode presents a superior rate capability (3.3-fold less reduction in capacity) and cycling stability (sustainable for 100 cycles), with a maximum capacity as large as 13.2 mAh cm-2 (6600 mAh gelectrode-1) at 1.0 mA cm-2. The proposed cathode exhibiting a binder-free and hierarchical core-shell structure is a promising candidate for rechargeable non-aqueous Li-O2 batteries.

  10. Fundamental degradation mechanisms of layered oxide Li-ion battery cathode materials: Methodology, insights and novel approaches

    Energy Technology Data Exchange (ETDEWEB)

    Hausbrand, R., E-mail: hausbrand@surface.tu-darmstadt.de; Cherkashinin, G.; Ehrenberg, H.; Gröting, M.; Albe, K.; Hess, C.; Jaegermann, W.

    2015-02-15

    Graphical abstract: - Highlights: • Description of recent in operando and in situ analysis methodology. • Surface science approach using photoemission for analysis of cathode surfaces and interfaces. • Ageing and fatigue of layered oxide Li-ion battery cathode materials from the atomistic point of view. • Defect formation and electronic structure evolution as causes for cathode degradation. • Significance of interfacial energy alignment and contact potential for side reactions. - Abstract: This overview addresses the atomistic aspects of degradation of layered LiMO{sub 2} (M = Ni, Co, Mn) oxide Li-ion battery cathode materials, aiming to shed light on the fundamental degradation mechanisms especially inside active cathode materials and at their interfaces. It includes recent results obtained by novel in situ/in operando diffraction methods, modelling, and quasi in situ surface science analysis. Degradation of the active cathode material occurs upon overcharge, resulting from a positive potential shift of the anode. Oxygen loss and eventual phase transformation resulting in dead regions are ascribed to changes in electronic structure and defect formation. The anode potential shift results from loss of free lithium due to side reactions occurring at electrode/electrolyte interfaces. Such side reactions are caused by electron transfer, and depend on the electron energy level alignment at the interface. Side reactions at electrode/electrolyte interfaces and capacity fade may be overcome by the use of suitable solid-state electrolytes and Li-containing anodes.

  11. Conditions for preparation of ultrapure beryllium by electrolytic refining in molten alkali-metal chlorides

    Energy Technology Data Exchange (ETDEWEB)

    Wohlfarth, Hagen

    1982-02-01

    Electrolytic refining is regarded as the most suitable process for the production of beryllium with impurity contents below 1 at.-ppM. Several parameters are important for electrolytic refining of beryllium in a BeCl/sub 2/-containing LiCl-KCl melt: current density, BeCl/sub 2/ content, electrolyte temperature, composition of the unpurified beryllium and impurity-ion concentrations in the melt, as well as apparatus characteristics such as rotation speed of the cathode and condition of the crucible material. These factors were studied and optimized such that extensive removal of the maximum number of accompanying and alloying elements was achieved.

  12. Recent development in electrolytic formation of carbon nanotubes in molten salts

    Directory of Open Access Journals (Sweden)

    Chen G.Z.

    2003-01-01

    Full Text Available This article reviews the recent research development in the electrolytic production of carbon nano-tubes in molten salts. The experimental procedure and product morphologies of the electrolytic method are described in details. Different hypotheses of the carbon nano-tube formation mechanism in molten salts, particularly it relation with the erosion of the cathode, are compared and discussed. It is anticipated that the electrolytic method can potentially become a cheap and continuous process for the production of curved carbon nano-tubes, carbon sheathed metal nanowires and other carbon based nano-structures.

  13. Solid State Multinuclear Magnetic Resonance Investigation of Electrolyte Decomposition Products on Lithium Ion Electrodes

    Science.gov (United States)

    DeSilva, J .H. S. R.; Udinwe, V.; Sideris, P. J.; Smart, M. C.; Krause, F. C.; Hwang, C.; Smith, K. A.; Greenbaum, S. G.

    2012-01-01

    Solid electrolyte interphase (SEI) formation in lithium ion cells prepared with advanced electrolytes is investigated by solid state multinuclear (7Li, 19F, 31P) magnetic resonance (NMR) measurements of electrode materials harvested from cycled cells subjected to an accelerated aging protocol. The electrolyte composition is varied to include the addition of fluorinated carbonates and triphenyl phosphate (TPP, a flame retardant). In addition to species associated with LiPF6 decomposition, cathode NMR spectra are characterized by the presence of compounds originating from the TPP additive. Substantial amounts of LiF are observed in the anodes as well as compounds originating from the fluorinated carbonates.

  14. Low temperature solid oxide fuel cells with proton-conducting Y:BaZrO{sub 3} electrolyte on porous anodic aluminum oxide substrate

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Seungbum [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); School of Mechanical and Aerospace Engineering, Seoul National University, Daehak-dong, Gwanak-gu, Seoul 151–742 (Korea, Republic of); Su, Pei-Chen [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Ji, Sanghoon [Graduate School of Convergence Science and Technology, Seoul National University, Daehak-dong, Gwanak-gu, Seoul 151–742 (Korea, Republic of); Cha, Suk Won, E-mail: swcha@snu.ac.kr [School of Mechanical and Aerospace Engineering, Seoul National University, Daehak-dong, Gwanak-gu, Seoul 151–742 (Korea, Republic of)

    2013-10-01

    This paper presents the architecture of a nano thin-film yttrium-doped barium zirconate (BYZ) solid-oxide fuel cell that uses nanoporous anodic aluminum oxide (AAO) as a supporting and gas-permeable substrate. The anode was fabricated by sputtering 300 nm platinum thin film that partially covered the AAO surface pores, followed by an additional conformal platinum coating to tune the pore size by atomic layer deposition. Two different nano-porous anode structures with a pore size of 10 nm or 50 nm were deposited. Proton-conducting BYZ ceramic electrolyte with increasing thicknesses of 300, 600, and 900 nm was deposited on top of the platinum anode by pulsed laser deposition, followed by a 200 nm layer of porous Pt sputtered on BYZ electrolyte as a cathode. The open circuit voltage (OCV) of the fuel cells was characterized at 250 °C with 1:1 volumetric stoichiometry of a methanol/water vapor mixture as the fuel. The OCVs were 0.17 V with a 900 nm-thick BYZ electrolyte on 50 nm pores and 0.3 V with a 600 nm-thick BYZ electrolyte on 10 nm pores, respectively, but it increased to 0.8 V for a 900 nm-thick BYZ electrolyte on 10 nm pores, indicating that increasing the film thickness and decreasing a surface pore size help to reduce the number of electrolyte pinholes and the gas leakage through the electrolyte. A maximum power density of 5.6 mW/cm{sup 2} at 250 °C was obtained from the fuel cell with 900 nm of BYZ electrolyte using methanol vapor as a fuel. - Highlights: • A low temperature ceramic fuel cell on nano-porous substrate was demonstrated. • A thin-film yttrium doped barium zirconate (BYZ) was deposited as an electrolyte. • An open circuit voltage (OCV) was measured to verify the BYZ film quality. • An OCV increased by increasing BYZ film thickness and decreasing pore size of anode. • The current–voltage performance was measured using vaporized methanol fuel at 250 °C.

  15. Spectroscopic studies of cathode materials for lithium-ion batteries

    Science.gov (United States)

    Totir, Dana Alexa

    2000-10-01

    Structural changes that occur during electrochemical cycling of lithium-ion battery cathode materials have been investigated using in situ spectroscopic techniques. A new method was developed for the preparation of carbon and binder free cathodes utilizing powder materials of interest for commercial batteries. The extraordinary quality of the cyclic voltammetric curves recorded for this type of electrodes during the in situ measurements allows direct correlations to be made between the state of charge of the material and its structural and electronic characteristics. LiCoO2, LiMn2O4 and LiCo0.15Ni 0.85O2 electrodes were evaluated using cycling voltammetry and the mean diffusion coefficient for Li-ions in the lattice (DLi) was calculated for LiMn2O4. LiMn2O4 electrodes prepared by this technique have been studied in situ using Mn K-edge XAS. Data analysis for the species formed at different potentials indicated a contraction of the lattice associated with the increase in the oxidation state of manganese. In situ Raman spectra of particles of LiMn2O 4, and LiCoO2 embedded in Au and also of KS-44 graphite and carbon microfibers MCF28 embedded in thermally annealed Ni have been recorded as a function of the applied potential. Fe K-edge XAFS of pyrite electrodes in a Li/PEO(LiClO4)/FeS 2 cell and S K-edge XANES measurements of a FeS2 electrode in a non-aqueous electrolyte have been acquired as a function of the state of charge. The studies have clearly evidenced the formation of metallic Fe and Li2S as intermediates after 4 e- discharge and the formation of Li2FeS2 after 2 e- recharge. While Fe K-edge studies have indicated that there is no change in the Fe environment and oxidation state upon 4 e- recharge, the results obtained from S K-edge studies are inconclusive for this stage. Finally, in situ Co K-edge XAFS data were obtained for the first time during the electrochemical cycling of electrodeposited Co(OH) 2 films in alkaline solutions. The results support

  16. Improved Rare-Earth Emitter Hollow Cathode

    Science.gov (United States)

    Goebel, Dan M.

    2011-01-01

    An improvement has been made to the design of the hollow cathode geometry that was created for the rare-earth electron emitter described in Compact Rare Earth Emitter Hollow Cathode (NPO-44923), NASA Tech Briefs, Vol. 34, No. 3 (March 2010), p. 52. The original interior assembly was made entirely of graphite in order to be compatible with the LaB6 material, which cannot be touched by metals during operation due to boron diffusion causing embrittlement issues in high-temperature refractory materials. Also, the graphite tube was difficult to machine and was subject to vibration-induced fracturing. This innovation replaces the graphite tube with one made out of refractory metal that is relatively easy to manufacture. The cathode support tube is made of molybdenum or molybdenum-rhenium. This material is easily gun-bored to near the tolerances required, and finish machined with steps at each end that capture the orifice plate and the mounting flange. This provides the manufacturability and robustness needed for flight applications, and eliminates the need for expensive e-beam welding used in prior cathodes. The LaB6 insert is protected from direct contact with the refractory metal tube by thin, graphite sleeves in a cup-arrangement around the ends of the insert. The sleeves, insert, and orifice plate are held in place by a ceramic spacer and tungsten spring inserted inside the tube. To heat the cathode, an insulating tube is slipped around the refractory metal hollow tube, which can be made of high-temperature materials like boron nitride or aluminum nitride. A screw-shaped slot, or series of slots, is machined in the outside of the ceramic tube to constrain a refractory metal wire wound inside the slot that is used as the heater. The screw slot can hold a single heater wire that is then connected to the front of the cathode tube by tack-welding to complete the electrical circuit, or it can be a double slot that takes a bifilar wound heater with both leads coming out

  17. Effect of interlayer on structure and performance of anode-supported SOFC single cells.

    Science.gov (United States)

    Eom, Tae Wook; Yang, Hae Kwang; Kim, Kyung Hwan; Yoon, Hyon Hee; Kim, Jong Sung; Park, Sang Joon

    2008-09-01

    To lower the operating temperatures in solid oxide fuel cell (SOFC) operations, anode-supported SOFC single cells with a single dip-coated interlayer were fabricated and the effect of the interlayer on the electrolyte structure and the electrical performance was investigated. For the preparation of SOFC single cells, yttria-stabilized zirconia (YSZ) electrolyte, NiO-YSZ anode, and 50% YSZ-50% strontium-doped lanthanum manganite (LSM) cathode were used. In order to characterize the cells, scanning electron microscopy (SEM) and atomic force microscopy (AFM) were utilized and the gas (air) permeability measurements were conducted for gas tightness estimation. When the interlayer was inserted onto NiO-YSZ anode, the surface roughness of anode was diminished by about 40% and dense crack-free electrolytes were obtained. The electrical performance was enhanced remarkably and the maximum power density was 0.57 W/cm(2) at 800 degrees C and 0.44 W/cm(2) at 700 degrees C. On the other hand, the effect of interlayer on the gas tightness was negligible. The characterization study revealed that the enhancement in the electrical performance was mainly attributed to the increase of ion transmission area of anode/electrolyte interface and the increase of ionic conductivity of dense crack-free electrolyte layer.

  18. Cathodic contact glow discharge electrolysis: its origin and non-faradaic chemical effects

    Science.gov (United States)

    Gupta, Susanta K. Sen; Singh, Rajshree

    2017-01-01

    Normal electrolysis (NE), at sufficiently high voltages, breaks down and undergoes a transition to a phenomenon called contact glow discharge electrolysis (CGDE) in which a sheath of glow discharge plasma encapsulates one of the electrodes, the anode or the cathode. The chemical effects of CGDE are highly non-faradaic e.g. a mixture of H2 and H2O2 plus O2 each in excess of the Faraday law value is liberated at the glow discharge plasma electrode from an aqueous electrolyte solution. Studies of cathodic CGDE, particularly its origin and chemical effects, in comparison to those of anodic CGDE have received significantly less attention and have not been studied in detail. The present paper is an attempt towards elucidation of the mechanisms of the growth of cathodic CGDE during NE and its non-faradaic chemical effects. The findings of the study have led to the inference that emission of secondary electrons from the metal cathode with sufficient kinetic energies, vaporization of the electrolyte solvent in the vicinity of the cathode surface induced by Joule heating and the onset of hydrodynamic instabilities in local vaporization contribute to the generation of the plasma at the cathode during NE. The findings have further shown that non-faradaic yields of CGDE at the cathode originate from energy transfer processes in two reaction zones: a plasma phase reaction zone around the cathode which accounts for ~75% of the yields, and a liquid phase reaction zone near the plasma-catholyte solution interface accounting for the remaining ~25% of the yields.

  19. Mechanism of Reaction in NaAlCl4 Molten Salt Batteries with Nickel Felt Cathodes and Aluminum Anodes. Part I: Modelling of the Battery Properties at Thermodynamic Equilibrium

    DEFF Research Database (Denmark)

    Knutz, B.C.; Hjuler, Hans Aage; Berg, Rolf W.;

    1993-01-01

    corresponding Variation of anode potential, cathode potential, and cell voltage as a function of electrolyte composition. For sulfide containing cells the plateau of lowest potential has been found to be associated with essentially pure nickel sulfide, NiySz. A procedure for model fitting to the cathode...

  20. New polymer lithium secondary batteries based on ORMOCER (R) electrolytes-inorganic-organic polymers

    DEFF Research Database (Denmark)

    Popall, M.; Buestrich, R.; Semrau, G.

    2001-01-01

    Based on new plasticized inorganic-organic polymer electrolytes CM. Popall, M. Andrei, J. Kappel, J. Kron, K. Olma, B. Olsowski,'ORMOCERs as Inorganic-organic Electrolytes for New Solid State Lithium Batteries and Supercapacitors', Electrochim. Acta 43 (1998) 1155] new flexible foil-batteries in ......Based on new plasticized inorganic-organic polymer electrolytes CM. Popall, M. Andrei, J. Kappel, J. Kron, K. Olma, B. Olsowski,'ORMOCERs as Inorganic-organic Electrolytes for New Solid State Lithium Batteries and Supercapacitors', Electrochim. Acta 43 (1998) 1155] new flexible foil......-batteries in 'coffee bag arrangement' were assembled and tested. The electrolyte works as separator and binder for the cathodes. Self-diffusion NMR studies on the system (EC/PC/Li+N(SO2CF3)(2)(-)/ORMOCER(R)) resulted in cationic transport numbers t(+)) of 0.42 for the EC/PC/salt system and 0.35 for the ternary...

  1. On electrochemical devices using alkaline polymer electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Zhuang, L. [Wuhan Univ., Wuhan (China). Dept. of Chemistry

    2010-07-01

    Solid polymer electrolytes (SPEs) enable a compact assembly of fuel cells and electrolyzers, thereby increasing the space-specific conversion efficiency and avoiding electrolyte leakage. The most widely used SPE in proton exchange membrane fuel cells (PEMFC) and chloro-alkali electrolyzers is Nafion. However, this strongly acidic polyelectrolyte allows only noble metals to be used as the catalysts in the electrochemical devices, which poses a problem in terms of price and resource limits. In principle, alkaline polymer electrolytes (APEs) should be used to eliminate the dependence on noble metal catalysts. The general structure of alkaline polymer electrolytes is a positively charged polymer, notably, a polymer chain attached with fixed cations such as quaternary ammonia group, and dissociated anion, OH-, to act as the charge carrier. This presentation described the challenges of developing APEs in terms of the chemical stability of quaternary ammonia group, the mobility of OH-, and high ionic concentration. The authors have been working on developing high-performance APEs since 2001. The most recent APEs were quaternary ammonia polysulfone (QAPS), which were found to be suitable for fuel cell and electrolyzer applications. The ionic conductivity was high and the crosslinked membrane had excellent mechanical strength, enabling operation at 90 degrees C. Non-precious metal catalysts were used in the APEs. For APE-based fuel cells (APEFC), chromium decorated nickel was used as the anode catalyst for hydrogen oxidation, and silver was used as the cathode catalyst for oxygen reduction. The preliminary performance of such an APEFC with non-Pt catalysts was found to be much better than that of traditional water electrolyzers using KOH solutions. 2 refs.

  2. Discharge-charge process of the porous sulfur/carbon nanocomposite cathode for rechargeable lithium sulfur batteries

    Science.gov (United States)

    Gao, Mengyao; Xiong, Xing; Wang, Weikun; Zhao, Shengrong; Li, Chengming; Zhang, Hao; Yu, Zhongbao; Huang, Yaqin

    2014-02-01

    The discharge-charge process of the porous sulfur/carbon nanocomposite cathode has been investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), electrochemical impedance spectroscopy (EIS), and energy-dispersive X-ray spectroscopy (EDS). The results indicate that the porous nanocomposite enhances the electrolyte infiltrate into the cathode materials evenly, has a good capability of confining the soluble polysulfides and preventing the aggregation of insoluble Li2S. The regenerated elemental sulfur of the porous sulfur/carbon nanocomposite cathode exists in nano-size particles in the pore and the resistance decreases compared with the original cathode. Moreover, the porous nanocomposite realizes the micro-reactors during the discharge-charge process and can accommodate the volume change which is benefit for stabilization of the cathode during the electrochemical reaction.

  3. Temperature variation of a thermionic cathode during electron emission

    Institute of Scientific and Technical Information of China (English)

    LIU YanWen; TIAN Hong; HAN Yong; XU ZhenYing; MENG MingFeng; ZHANG HongLai

    2008-01-01

    It is necessary to know the actual temperature of a thermionic cathode that works as the electron source in a microwave tube. It has been found that the temperature of the cathode drops markedly during the thermionic emission. For example, the temperature could fall by about 30℃ under a current density of 2.92 A/cm2. Using the molecular thermodynamics, the dependence of the cathode temperature on the emission current density has been obtained. It has been theoretically pointed out that several factors, such as heating model and temperature coefficient of resis- tance of heater, can influence the cathode temperature. These theoretical conclu- sions were supported by the experimental results.

  4. Macroparticle generation in DC arc discharge from a WC cathode

    Science.gov (United States)

    Zhirkov, Igor; Polcik, Peter; Kolozsvári, Szilard; Rosen, Johanna

    2017-03-01

    We have studied macroparticle generation from a tungsten carbide cathode used in a dc vacuum arc discharge. Despite a relatively high decomposition/melting point (˜3100 K), there is an intensive generation of visible particles with sizes in the range 20-35 μm. Visual observations during the discharge and scanning electron microscopy of the cathode surface and of collected macroparticles indicate a new mechanism for particle formation and acceleration. Based on the W-C phase diagram, there is an intensive sublimation of carbon from the melt resulting from the cathode spot. The sublimation supports the formation of a sphere, which is accelerated upon an explosion initiated by Joule heating at the critical contact area between the sphere and the cathode body. The explosive nature of the particle acceleration is confirmed by surface features resembling the remains of a splash on the droplet surface.

  5. Temperature variation of a thermionic cathode during electron emission

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    It is necessary to know the actual temperature of a thermionic cathode that works as the electron source in a microwave tube. It has been found that the temperature of the cathode drops markedly during the thermionic emission. For example, the temperature could fall by about 30oC under a current density of 2.92 A/cm2. Using the molecular thermodynamics, the dependence of the cathode temperature on the emission current density has been obtained. It has been theoretically pointed out that several factors, such as heating model and temperature coefficient of resis-tance of heater, can influence the cathode temperature. These theoretical conclu-sions were supported by the experimental results.

  6. Solid electrolytic fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Sakai, Masayasu; Yamauchi, Yasuhiro; Kamisaka, Mitsuo; Notomi, Kei.

    1989-04-21

    Concerning a solid electrolytic fuel cell with a gas permeable substrate pipe, a fuel electrode installed on this substrate pipe and an air electrode which is laminated on this fuel electrode with the electrolyte in between, the existing fuel cell of this kind uses crystals of CaMnO3, etc. for the material of the air electrode, but its electric resistance is big and in order to avert this, it is necessary to make the film thickness of the air electrode big. However, in such a case, the entry of the air into its inside worsens and the cell performance cannot develop satisfactorily. In view of the above, in order to obtain a high performance solid electrolytic fuel cell which can improve electric conductivity without damaging diffusion rate of the air, this invention proposes with regard to the aforementioned solid electrolytic fuel cell to install a heat resistant and conductive member inside the above air electrode. 6 figs.

  7. Electrolytic oxidation of anthracite

    Science.gov (United States)

    Senftle, F.E.; Patton, K.M.; Heard, I.

    1981-01-01

    An anthracite slurry can be oxidized only with difficulty by electrolytic methods in which aqueous electrolytes are used if the slurry is confined to the region of the anode by a porous pot or diaphragm. However, it can be easily oxidized if the anthracite itself is used as the anode. No porous pot or diaphragm is needed. Oxidative consumption of the coal to alkali-soluble compounds is found to proceed preferentially at the edges of the aromatic planes. An oxidation model is proposed in which the chief oxidants are molecular and radical species formed by the electrolytic decomposition of water at the coal surface-electrolyte interface. The oxidation reactions proposed account for the opening of the aromatic rings and the subsequent formation of carboxylic acids. The model also explains the observed anisotropic oxidation and the need for the porous pot or diaphragm used in previous studies of the oxidation of coal slurries. ?? 1981.

  8. Suppressing Manganese Dissolution from Lithium Manganese Oxide Spinel Cathodes with Single-Layer Graphene

    Energy Technology Data Exchange (ETDEWEB)

    Jaber-Ansari, Laila; Puntambekar, Kanan P.; Kim, Soo; Aykol, Muratahan; Luo, Langli; Wu, Jinsong; Myers, Benjamin D.; Iddir, Hakim; Russell, John T.; Saldana, Spencer J.; Kumar, Rajan; Thackeray, Michael M.; Curtiss, Larry A.; Dravid, Vinayak P.; Wolverton, Christopher M.; Hersam, Mark C.

    2015-06-24

    Spinel-structured LiMn 2 O 4 (LMO) is a desirable cathode material for Li-ion batteries due to its low cost, abundance, and high power capability. However, LMO suffers from limited cycle life that is triggered by manganese dissolution into the electrolyte during electrochemical cycling. Here, it is shown that single-layer graphene coatings suppress manganese dissolution, thus enhancing the performance and lifetime of LMO cathodes. Relative to lithium cells with uncoated LMO cathodes, cells with graphene-coated LMO cathodes provide improved capacity retention with enhanced cycling stability. X-ray photoelectron spectroscopy reveals that graphene coatings inhibit manganese depletion from the LMO surface. Additionally, transmission electron microscopy demonstrates that a stable solid electrolyte interphase is formed on graphene, which screens the LMO from direct contact with the electrolyte. Density functional theory calculations provide two mechanisms for the role of graphene in the suppression of manganese dissolution. First, common defects in single-layer graphene are found to allow the transport of lithium while concurrently acting as barriers for manganese diffusion. Second, graphene can chemically interact with Mn 3+ at the LMO electrode surface, promoting an oxidation state change to Mn 4+ , which suppresses dissolution.

  9. Electrolyte effects on hydrogen evolution and solution resistance in microbial electrolysis cells

    Science.gov (United States)

    Merrill, Matthew D.; Logan, Bruce E.

    Protonated weak acids commonly used in microbial electrolysis cell (MEC) solutions can affect the hydrogen evolution reaction (HER) through weak acid catalysis, and by lowering solution resistance between the anode and the cathode. Weak acid catalysis of the HER with protonated phosphate, acetate, and carbonate electrolyte species improved MEC performance by lowering the cathode's overpotential by up to 0.30 V at pH 5, compared to sodium chloride electrolytes. Deprotonation of weak acids into charged species at higher pHs improved MEC performance primarily by increasing the electrolyte's conductivity and therefore decreasing the solution resistance between electrodes. The potential contributions from weak acid catalysis and solution resistance were compared to determine whether a reactor would operate more efficiently at lower pH because of the HER, or at higher pH because of solution resistance. Phosphate and acetate electrolytes allowed the MEC to operate more efficiently under more acidic conditions (pH 5). Carbonate electrolytes increased performance from pH 5 to 9 due to a relatively large increases in conductivity. These results demonstrate that specific buffers can substantially contribute to MEC performance through both reduction in cathode overpotential and solution resistance.

  10. A Safer Sodium-Ion Battery Based on Nonflammable Organic Phosphate Electrolyte.

    Science.gov (United States)

    Zeng, Ziqi; Jiang, Xiaoyu; Li, Ran; Yuan, Dingding; Ai, Xinping; Yang, Hanxi; Cao, Yuliang

    2016-09-01

    Sodium-ion batteries are now considered as a low-cost alternative to lithium-ion technologies for large-scale energy storage applications; however, their safety is still a matter of great concern for practical applications. In this paper, a safer sodium-ion battery is proposed by introducing a nonflammable phosphate electrolyte (trimethyl phosphate, TMP) coupled with NaNi0.35Mn0.35Fe0.3O2 cathode and Sb-based alloy anode. The physical and electrochemical compatibilities of the TMP electrolyte are investigated by igniting, ionic conductivity, cyclic voltammetry, and charge-discharge measurements. The results exhibit that the TMP electrolyte with FEC additive is completely nonflammable and has wide electrochemical window (0-4.5 V vs. Na/Na(+)), in which both the Sb-based anode and NaNi0.35Mn0.35Fe0.3O2 cathode show high reversible capacity and cycling stability, similarly as in carbonate electrolyte. Based on these results, a nonflammable sodium-ion battery is constructed by use of Sb anode, NaNi0.35Mn0.35Fe0.3O2 cathode, and TMP + 10 vol% FEC electrolyte, which works very well with considerable capacity and cyclability, demonstrating a promising prospect to build safer sodium-ion batteries for large-scale energy storage applications.

  11. Chromium poisoning in (La,Sr)MnO3 cathode: Three-dimensional simulation of a solid oxide fuel cell

    Science.gov (United States)

    Miyoshi, Kota; Iwai, Hiroshi; Kishimoto, Masashi; Saito, Motohiro; Yoshida, Hideo

    2016-09-01

    A three-dimensional numerical model of a single solid oxide fuel cell (SOFC) considering chromium poisoning on the cathode side has been developed to investigate the evolution of the SOFC performance over long-term operation. The degradation model applied in the simulation describes the loss of the cathode electrochemical activity as a decrease in the active triple-phase boundary (TPB) length. The calculations are conducted for two types of cell: lanthanum strontium manganite (LSM)/yttria-stabilized zirconia (YSZ)/Ni-YSZ and LSM-YSZ/YSZ/Ni-YSZ. Their electrode microstructures are acquired by imaging with a focused ion beam scanning-electron microscope (FIB-SEM). The simulation results qualitatively reproduce the trends of chromium poisoning reported in the literature. It has been revealed that the performance degradation by chromium is primarily due to an increase in the cathode activation overpotential. In addition, in the LSM-YSZ composite cathode, TPBs in the vicinity of the cathode-electrolyte interface preferentially deteriorate, shifting the active reaction site towards the cathode surface. This also results in an increase in the cathode ohmic loss associated with oxide ion conduction through the YSZ phase. The effects of the cell temperature, the partial pressure of steam at the chromium source, the cathode microstructure, and the cathode thickness on chromium poisoning are also discussed.

  12. CO₂ and O₂ evolution at high voltage cathode materials of Li-ion batteries: a differential electrochemical mass spectrometry study.

    Science.gov (United States)

    Wang, Hongsen; Rus, Eric; Sakuraba, Takahito; Kikuchi, Jun; Kiya, Yasuyuki; Abruña, Héctor D

    2014-07-01

    A three-electrode differential electrochemical mass spectrometry (DEMS) cell has been developed to study the oxidative decomposition of electrolytes at high voltage cathode materials of Li-ion batteries. In this DEMS cell, the working electrode used was the same as the cathode electrode in real Li-ion batteries, i.e., a lithium metal oxide deposited on a porous aluminum foil current collector. A charged LiCoO2 or LiMn2O4 was used as the reference electrode, because of their insensitivity to air, when compared to lithium. A lithium sheet was used as the counter electrode. This DEMS cell closely approaches real Li-ion battery conditions, and thus the results obtained can be readily correlated with reactions occurring in real Li-ion batteries. Using DEMS, the oxidative stability of three electrolytes (1 M LiPF6 in EC/DEC, EC/DMC, and PC) at three cathode materials including LiCoO2, LiMn2O4, and LiNi(0.5)Mn(1.5)O4 were studied. We found that 1 M LiPF6 + EC/DMC electrolyte is quite stable up to 5.0 V, when LiNi(0.5)Mn(1.5)O4 is used as the cathode material. The EC/DMC solvent mixture was found to be the most stable for the three cathode materials, while EC/DEC was the least stable. The oxidative decomposition of the EC/DEC mixture solvent could be readily observed under operating conditions in our cell even at potentials as low as 4.4 V in 1 M LiPF6 + EC/DEC electrolyte on a LiCoO2 cathode, as indicated by CO2 and O2 evolution. The features of this DEMS cell to unveil solvent and electrolyte decomposition pathways are also described.

  13. Ultrasonic-assisted cathodic electrochemical discharge for graphene synthesis.

    Science.gov (United States)

    Van Thanh, Dang; Oanh, Phung Phi; Huong, Do Tra; Le, Phuoc Huu

    2017-01-01

    We present a novel and highly efficient method for exfoliating of graphite to produce graphene via the synergistic effects of in-situ plasma induced electrochemical exfoliation with ultrasonic energy, called ultrasonic-assisted cathodic electrochemical discharge. This method can work at moderate temperatures without the need of acidic media or expensive ionic electrolyte. The produced graphene exhibited a large lateral dimension of approximately 6μm and a thickness of 2.5nm, corresponding to approximately seven layers of graphene. An exfoliating mechanism of graphite to produce graphene sheets is also proposed in this study.

  14. Copper oxide as a high temperature battery cathode material

    Science.gov (United States)

    Ritchie, A. G.; Mullins, A. P.

    1994-10-01

    Copper oxide has been tested as a cathode material for high temperature primary reserve thermal batteries in single cells at 530 to 600 C and at current densities of 0.1 to 0.25 A cm(exp -2) using lithium-aluminium alloy anodes and lithium fluoride-lithium chloride-lithium bromide molten salt electrolytes. Initial on-load voltages were around 2.3 V, falling to 1.5 V after about 0.5 F mol(exp -1) had been withdrawn. Lithium copper oxide, LiCu2O2, and cuprous oxide, Cu2O, were identified as discharge products.

  15. Nanoscale Organic Hybrid Electrolytes

    KAUST Repository

    Nugent, Jennifer L.

    2010-08-20

    Nanoscale organic hybrid electrolytes are composed of organic-inorganic hybrid nanostructures, each with a metal oxide or metallic nanoparticle core densely grafted with an ion-conducting polyethylene glycol corona - doped with lithium salt. These materials form novel solvent-free hybrid electrolytes that are particle-rich, soft glasses at room temperature; yet manifest high ionic conductivity and good electrochemical stability above 5V. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Bio-inspired Construction of Advanced Fuel Cell Cathode with Pt Anchored in Ordered Hybrid Polymer Matrix

    Science.gov (United States)

    Xia, Zhangxun; Wang, Suli; Jiang, Luhua; Sun, Hai; Liu, Shuang; Fu, Xudong; Zhang, Bingsen; Sheng Su, Dang; Wang, Jianqiang; Sun, Gongquan

    2015-01-01

    The significant use of platinum for catalyzing the cathodic oxygen reduction reactions (ORRs) has hampered the widespread use of polymer electrolyte membrane fuel cells (PEMFCs). The construction of well-defined electrode architecture in nanoscale with enhanced utilization and catalytic performance of Pt might be a promising approach to address such barrier. Inspired by the highly efficient catalytic processes in enzymes with active centers embedded in charge transport pathways, here we demonstrate for the first time a design that allocates platinum nanoparticles (Pt NPs) at the boundaries with dual-functions of conducting both electrons by aid of polypyrrole and protons via Nafion® ionomer within hierarchical nanoarrays. By mimicking enzymes functionally, an impressive ORR activity and stability is achieved. Using this brand new electrode architecture as the cathode and the anode of a PEMFC, a high mass specific power density of 5.23 W mg−1Pt is achieved, with remarkable durability. These improvements are ascribed to not only the electron decoration and the anchoring effects from the Nafion® ionomer decorated PPy substrate to the supported Pt NPs, but also the fast charge and mass transport facilitated by the electron and proton pathways within the electrode architecture. PMID:26537781

  17. A Study on Zinc-Iron Alloy Electrodeposition from a Chloride Electrolyte

    DEFF Research Database (Denmark)

    Jensen, Jens Dahl

    1998-01-01

    The electrodeposition of zinc-iron alloys from a chloride-based electrolyte has been studied using electrochemical polarisation techniques, Auger Electron Spectroscopy (AES), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Analysis (EDXA) and Computer Assisted Pulse Plating (CAPP......). A change in the electrodeposition mechanism from equilibrium codeposition to anomalous codeposition with a change in cathodic current density has been observed. Zn-Fe alloys with compositions ranging from 5 wt-% to more than 75 wt-% Fe have been electrodeposited from a single electrolyte, making...... this system ideal for production of compositional modulated alloy (CMA) electrodeposits. Chloride content, pH and agitation of the electrolyte have been observed to have a strong influence on the reaction at the cathode surface, just as the use of pulse reversal current during electrodeposition. A theory...

  18. Fabrication of electrocatalyst based on nitrogen doped graphene as highly efficient and durable support for using in polymer electrolyte fuel cell

    Science.gov (United States)

    Heydari, Ahmad; Gharibi, Hussein

    2016-09-01

    In this work, we have used an efficient approach to prepare nitrogen-doped graphene supported Pt nanoparticles (Pt/N-rGO). The nitrogen-doped graphene nanocomposites (N-rGO) were derived from pyrolysis of graphene oxide/polyaniline composites in nitrogen atmosphere. X-ray powder diffraction, FTIR spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and Transmission and Scanning electron microscopy (TEM&SEM) were used to characterize the morphology and microstructure of the prepared catalysts. The TEM and elemental mapping images indicate that metal nanoparticles are more uniformly dispersed on the surface of N-doped graphene than other supports, and Pt nanoparticles dispersed without any aggregation. The catalytic activity and durability of the catalysts was evaluated by various electrochemical techniques. Compared to undoped Pt/rGO and commercial Pt/C catalysts, an enhanced electrocatalytic activity was obtained in the case of the Pt/N-rGO with optimized composition and nanostructure. The maximum power density of MEA for Pt/N-rGO was 1.4 times more than that of MEA fabricated by commercial Pt/C 20%.

  19. Electrical and electrochemical properties of magnesium ion conducting composite gel polymer electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, G P; Hashmi, S A [Department of Physics and Astrophysics, University of Delhi, Delhi-110007 (India); Agrawal, R C, E-mail: sahashmi@physics.du.ac.i [School of Studies in Physics, Pt. Ravishankar Shukla University, Raipur-492010, Chhattisgarh (India)

    2010-06-30

    The effect of micro- and nano-sized MgO and nano-sized SiO{sub 2} dispersion on the electrical and electrochemical properties of poly(vinylidene fluoride-hexafluoropropylene) (PVdF-HFP) based Mg{sup 2+} ion conducting gel polymer electrolyte has been investigated. The gel electrolytes have been characterized using electrical conductivity, cationic transport number (t{sub +}) measurements and cyclic voltammetry. A two-maxima feature has been observed in the 'conductivity versus composition' curve at {approx}3 wt% and 10-15 wt% of the filler contents. The highest conductivity has been obtained for the SiO{sub 2} dispersed gel electrolyte of {approx}1 x 10{sup -2} S cm{sup -1} for 3 wt% and {approx}9 x 10{sup -3} S cm{sup -1} at 15 wt% content. The value of 't{sub +}' is found to be enhanced substantially with increasing amount of MgO (both micro- and nanoparticles), whereas in the case of SiO{sub 2} dispersion the value does not increase substantially. The highest 't{sub +}' value of {approx}0.44 has been obtained for the addition of 10 wt% MgO nanoparticles. The enhancement in 't{sub +}' is explained on the basis of the formation of space-charge regions due to the presence of MgO : Mg{sup 2+}-like species, which supports Mg{sup 2+} ion motion. A substantial increase in the amount of anodic and cathodic peak currents is observed due to the addition of nano-sized MgO particles in the gel polymer electrolyte, whereas in the cases of micrometre-sized MgO and nano-sized SiO{sub 2} the enhancement is not significant. The enhancement in conductivity in SiO{sub 2} dispersed nanocomposite gel electrolyte is predominantly due to anionic motion.

  20. Cathodic hydrodimerization of nitroolefins

    Directory of Open Access Journals (Sweden)

    Michael Weßling

    2015-07-01

    Full Text Available Nitroalkenes are easily accessible in high variety by condensation of aldehydes with aliphatic nitroalkanes. They belong to the group of activated alkenes that can be hydrodimerized by cathodic reduction. There are many olefins with different electron withdrawing groups used for cathodic hydrodimerization, but not much is known about the behaviour of the nitro group. Synthetic applications of this group could profit from the easy access to nitroolefins in large variety, the C–C bond formation with the introduction of two nitro groups in a 1,4-distance and the conversions of the nitro group by reduction to oximes and amines, the conversion into aldehydes and ketones via the Nef reaction and base catalyzed condensations at the acidic CH bond. Eight 1-aryl-2-nitro-1-propenes have been electrolyzed in an undivided electrolysis cell to afford 2,5-dinitro-3,4-diaryl hexanes in high yield. The 4-methoxy-, 4-trifluoromethyl-, 2-chloro- and 2,6-difluorophenyl group and furthermore the 2-furyl and 2-pyrrolyl group have been applied. The reaction is chemoselective as only the double bond but not the nitro group undergoes reaction, is regioselective as a ß,ß-coupling with regard to the nitro group and forms preferentially two out of six possible diastereomers as major products.

  1. Cathodic hydrodimerization of nitroolefins.

    Science.gov (United States)

    Weßling, Michael; Schäfer, Hans J

    2015-01-01

    Nitroalkenes are easily accessible in high variety by condensation of aldehydes with aliphatic nitroalkanes. They belong to the group of activated alkenes that can be hydrodimerized by cathodic reduction. There are many olefins with different electron withdrawing groups used for cathodic hydrodimerization, but not much is known about the behaviour of the nitro group. Synthetic applications of this group could profit from the easy access to nitroolefins in large variety, the C-C bond formation with the introduction of two nitro groups in a 1,4-distance and the conversions of the nitro group by reduction to oximes and amines, the conversion into aldehydes and ketones via the Nef reaction and base catalyzed condensations at the acidic CH bond. Eight 1-aryl-2-nitro-1-propenes have been electrolyzed in an undivided electrolysis cell to afford 2,5-dinitro-3,4-diaryl hexanes in high yield. The 4-methoxy-, 4-trifluoromethyl-, 2-chloro- and 2,6-difluorophenyl group and furthermore the 2-furyl and 2-pyrrolyl group have been applied. The reaction is chemoselective as only the double bond but not the nitro group undergoes reaction, is regioselective as a ß,ß-coupling with regard to the nitro group and forms preferentially two out of six possible diastereomers as major products.

  2. Effect of cathode shape on vertical buffered electropolishing for niobium SRF cavities

    Science.gov (United States)

    Jin, S.; Wu, A. T.; Lu, X. Y.; Rimmer, R. A.; Lin, L.; Zhao, K.; Mammosser, J.; Gao, J.

    2013-09-01

    This paper reports the research results of the effect of cathode shape during vertical buffered electropolishing (BEP) by employing a demountable single cell niobium (Nb) superconducting radio frequency (SRF) cavity. Several different cathode shapes such as, for instance, bar, ball, ellipsoid, and wheels of different diameters have been tested. Detailed electropolishing parameters including I-V characteristic, removal rate, surface roughness, and polishing uniformity at different locations inside the demountable cavity are measured. Similar studies are also done on conventional electropolishing (EP) for comparison. It is revealed that cathode shape has dominant effects for BEP especially on the obtaining of a suitable polishing condition and a uniform polishing rate in an Nb SRF single cell cavity. EP appears to have the same tendency. This paper demonstrates that a more homogeneous polishing result can be obtained by optimizing the electric field distribution inside the cavity through the modification of the cathode shape given the conditions that temperature and electrolyte flow are kept constant. Electric field distribution and electrolyte flow patterns inside the cavity are simulated via Poisson-Superfish and Solidworks respectively. With the optimal cathode shape, BEP shows a much faster polishing rate of ∼2.5 μm/min and is able to produce a smoother surface finish in the treatments of single cell cavities in comparison with EP.

  3. A high performance BaZr0.1Ce0.7Y0.2O3-δ-based solid oxide fuel cell with a cobalt-free Ba0.5Sr0.5FeO3-δ–Ce0.8Sm0.2O2-δ composite cathode

    NARCIS (Netherlands)

    Sun, Wenping; Shi, Zhen; Fang, Shumin; Yan, Litao; Zhu, Zhiwen; Liu, Wei

    2010-01-01

    A cobalt-free Ba0.5Sr0.5FeO3-δ–Ce0.8Sm0.2O2-δ (BSF–SDC) composite is employed as a cathode for an anode-supported proton-conducting solid oxide fuel cells (H-SOFCs) using BaZr0.1Ce0.7Y0.2O3-δ (BZCY) as the electrolyte. The chemical compatibility between BSF and SDC is evaluated. The XRD results show

  4. Electrooxidation of H{sub 2}/CO on carbon-supported PtRuMo nanoparticles for polymer electrolyte fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Tsiouvaras, N.; Pena, M.A.; Fierro, J.L.G.; Martinez-Huerta, M.V. [CSIC, Madrid (Spain). Inst. de Catalisis y Petroleoquimica; Alcaide, F.; Alvarez, G. [CIDETEC-IK4, Donostia, San Sebastian (Spain)

    2010-07-01

    Ternary anodic PtRuMo catalysts have been prepared following a two step procedure. All catalysts prepared present PtRu metal loading of 30%wt and a Mo load of 0, 1, 2.5 and 5%wt supported on Vulcan XC 72R. Different physicochemical techniques have been employed for the analysis of the catalysts as well as electrochemical techniques in combination with FTIR for in situ studies. The fuel cell performance was evaluated at 80 C in a PEMFC fed with H{sub 2}/CO (10 ppm). Catalysts obtained exhibit good dispersion and small particle size (2.6 nm). FTIR results obtained in CO saturated confirm that lower amounts of CO are adsorbed on ternary catalysts compared with binary catalyst, whichever Mo composition was used. However, polarization curves of the catalysts show that the activity strongly depend on the composition, where PtRu-Mo(1%wt)/C displays the highest CO tolerance. (orig.)

  5. Electrolytic hydrogenation of anthracene and diesel fuel in CH3CN-EtOH-H2O-Bu4NBr electrolytic system%乙腈-乙醇-水-四丁基溴化铵体系中蒽和柴油的电解加氢

    Institute of Scientific and Technical Information of China (English)

    刘昌见; 李德宝; 鲍晓军; 杨世成; 李维彬; 胡胜; 张志华

    2005-01-01

    Electrochemical hydrogenation of anthracene was carried out in a divided three-electrode cell with spumous Pb as cathode, Pt as anode and saturated calomel electrode as reference electrode in CHa CN-EtOH-H2O-Bu4NBr electrolytic system. The curve of current-potential was determined and the effects of solvents, water content, supporting electrolyte, anthracene content and temperature were investigated. The optimum conditions were found as potential =-1900 mV, [CH3CN] / [EtOH] = 2/1 (vol) ,[H2O] =5.5 mol · L-1, [Bu4NBr] =0.50 mol· L-1 and T=35 ℃. The yield of dihydroanthracene was 91.37% for 6 h electrolysis under these conditions. Based on the result of electrochemical hydrogenation of anthracene, electrochemical hydrogenation of Daqing FCC diesel fuel was studied with spumous Pb as cathode in CH3CN-EtOH-H2O-Bu4NBr system for 5 h electrolysis. Hydrogen content of diesel fuel increased by 1.1%, alkenes were saturated and polycyclic aromatics decreased apparently.

  6. Production of planar copper-based anode supported intermediate temperature solid oxide fuel cells cosintered at 950 °C

    Science.gov (United States)

    De Marco, Vincenzo; Grazioli, Alberto; Sglavo, Vincenzo M.

    2016-10-01

    Copper-based anode supported planar Intermediate Temperature Solid Oxide Fuel Cells are produced and characterized in the present work. The most important advancement is related to the use of copper within the anodic layer, this giving promising results for feeding Intermediate Temperature Solid Oxide Fuel Cells with carbon and sulphur containing fuels. Both anode and Li2O containing-Gadolinia Doped Ceria based electrolyte are produced by water based tape casting process. The supporting anode is coupled to the electrolyte by thermopressing, the cathode being obtained by screen printing. A 3 h isotherm at 950 °C allows to obtain the cosintering of the three layers. The electrochemical test performed on such cells reveals a 0.8 V open circuit voltage and a power density higher than 26 mW cm-2 at 650 °C.

  7. Platinum nanoparticles on carbon-nanotube support prepared by room-temperature reduction with H2 in ethylene glycol/water mixed solvent as catalysts for polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Zheng, Yuying; Dou, Zhengjie; Fang, Yanxiong; Li, Muwu; Wu, Xin; Zeng, Jianhuang; Hou, Zhaohui; Liao, Shijun

    2016-02-01

    Polyol approach is commonly used in synthesizing Pt nanoparticles in polymer electrolyte membrane fuel cells. However, the application of this process consumes a great deal of time and energy, as the reduction of precursors requires elevated temperatures and several hours. Moreover, the ethylene glycol and its oxidizing products bound to Pt are difficult to remove. In this work, we utilize the advantages of ethylene glycol and prepare Pt nanoparticles through a room-temperature hydrogen gas reduction in an ethylene glycol/water mixed solvent, which is followed by subsequent harvesting by carbon nanotubes as electrocatalysts. This method is simple, facile, and time-efficient, as the entire room-temperature reduction process is completed in a few minutes. As the solvent changes from water to an ethylene glycol/water mix, the size of Pt nanoparticles varies from 10 to 3 nm and their shape transitions from polyhedral to spherical. Pt nanoparticles prepared in a 1:1 volume ratio mixture of ethylene glycol/water are uniformly dispersed with an average size of ∼3 nm. The optimized carbon nanotube-supported Pt electrocatalyst exhibits excellent methanol oxidation and oxygen reduction activities. This work demonstrates the potential use of mixed solvents as an approach in materials synthesis.

  8. Novel composite polymer electrolyte for lithium air batteries

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Deng; Li, Ruoshi; Huang, Tao; Yu, Aishui [Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Institute of New Energy, Fudan University, 220 Handan Road, Shanghai 200433 (China)

    2010-02-15

    Hydrophobic ionic liquid-silica-PVdF-HFP polymer composite electrolyte is synthesized and employed in lithium air batteries for the first time. Discharge performance of lithium air battery using this composite electrolyte membrane in ambient atmosphere shows a higher capacity of 2800 mAh g{sup -1} of carbon in the absence of O{sub 2} catalyst, whereas, the cell with pure ionic liquid as electrolyte delivers much lower discharge capacity of 1500 mAh g{sup -1}. When catalyzed by {alpha}-MnO{sub 2}, the initial discharge capacity of the cell with composite electrolyte can be extended to 4080 mAh g{sup -1} of carbon, which can be calculated as 2040 mAh g{sup -1} associated with the total mass of the cathode. The flat discharge plateau and large discharge capacity indicate that the hydrophobic ionic liquid-silica-PVdF-HFP polymer composite electrolyte membrane can effectively protect lithium from moisture invasion. (author)

  9. CHARACTERISTICS OF NEW CATHODE MATERIAL FOR LTSOFC INVESTIGATED BY IMPEDANCE SPECTROSCOPY

    Institute of Scientific and Technical Information of China (English)

    彭冉冉; 杨立寨; 毛宗强; 谢晓峰

    2004-01-01

    The characteristics of a new Li-NiO cathode were investigated. The crystal structure of Li-NiO was explored by XRD. Electrochemical behaviors of Li-NiO composite cathode were revealed by impedance spectroscopy from 400℃ to 650℃. The diameter of deformed arc increased with the decrease of temperature. Above the melting point of the eutectic salt in composite electrolyte, the Li-NiO curves are similar with two deformed semicircular arcs at high frequency which partially overlaps each other and corresponds...

  10. Characterisation of porous cathodes for application in solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Van Heuveln, F.H.

    1997-10-01

    For the future development of a solid oxide fuel cell a high level of understanding of the basic operation of such a device is a prerequisite. It is considered that further improvement requires solutions of the problems of ohmic and interfacial polarisation losses at the cathodic side of the cell. Despite large research efforts there is still no general consensus about the fundamental electrochemical processes at the cathode/electrolyte interface. The aim of this thesis is to contribute to the optimisation of the state-of-the-art SOFC cathode. The correlation between the electrochemical performance of several cathodes and its microstructure is subject of Chap. 2 and 3. These cathodes have the composition Sr{sub x}La{sub 1-x}MnO{sub 3} (SLM) which is the state-of-the-art cathode material for the high temperature SOFC. To investigate the electrochemical properties, impedance spectroscopy and current-voltage measurements are used as the main characterisation tools. The relationship observed between the electrochemical performance and the degree of electrode coverage on the electrolyte surface is analysed in terms of the three-phase boundary area in Chap. 3. The oxygen electrode kinetics of the SLM cathode is described in Chap. 4. In Chap. 5 the constriction of the current lines is modelled for different geometries of the contact between electrode and electrolyte, and the results are compared with the experimental data given in Chap. 2 and 3. In Chap. 6 the kinetics of the low temperature SOFC cathode La{sub 0.6}Sr{sub 0.4}Co{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}} (LSCF) on a gadolinia doped ceria electrolyte is described. Besides impedance spectroscopy the current interruption method can be used to characterise electrochemical interfaces. Its use in basic SOFC research is described in Chap. 7. Experimental errors which may arise by improper positioning of the reference electrode in a three-electrode cell configuration are discussed in the App. of this thesis.

  11. Advanced rechargeable aluminium ion battery with a high-quality natural graphite cathode

    OpenAIRE

    Wang, Di-Yan; Wei, Chuan-yu; Lin, Meng-Chang; Pan, Chun-Jern; Chou, Hung-Lung; Chen, Hsin-An; Gong, Ming; Wu, Yingpeng; Yuan, Chunze; Angell, Michael; Hsieh, Yu-Ju; Chen, Yu-Hsun; Wen, Cheng-Yen; Chen, Chun-Wei; Hwang, Bing-Joe

    2017-01-01

    Recently, interest in aluminium ion batteries with aluminium anodes, graphite cathodes and ionic liquid electrolytes has increased; however, much remains to be done to increase the cathode capacity and to understand details of the anion–graphite intercalation mechanism. Here, an aluminium ion battery cell made using pristine natural graphite flakes achieves a specific capacity of ∼110 mAh g−1 with Coulombic efficiency ∼98%, at a current density of 99 mA g−1 (0.9 C) with clear discharge voltag...

  12. Fluid and Electrolyte Nutrition

    Science.gov (United States)

    Lane, Helen W.; Smith, Scott M.; Leach, Carolyn S.; Rice, Barbara L.

    1999-01-01

    Studies of fluid and electrolyte homeostasis have been completed since the early human space flight programs, with comprehensive research completed on the Spacelab Life Sciences missions SLS-1 and SLS-2 flights, and more recently on the Mir 18 mission. This work documented the known shifts in fluids, the decrease in total blood volume, and indications of reduced thirst. Data from these flights was used to evaluate the nutritional needs for water, sodium, and potassium. Interpretations of the data are confounded by the inadequate energy intakes routinely observed during space flight. This in turn results in reduced fluid intake, as food provides approximately 70% water intake. Subsequently, body weight, lean body mass, total body water, and total body potassium may decrease. Given these issues, there is evidence to support a minimum required water intake of 2 L per day. Data from previous Shuttle flights indicated that water intake is 2285 +/- 715 ml/day (mean +/- SD, n=26). There are no indications that sodium intake or homeostasis is compromised during space flight. The normal or low aldosterone and urinary sodium levels suggest adequate sodium intake (4047 +/- 902 mg/day, n=26). Because excessive sodium intake is associated with hypercalciuria, the recommended maximum amount of sodium intake during flight is 3500 mg/day (i.e., similar to the Recommended Dietary Allowance, RDA). Potassium metabolism appears to be more complex. Data indicate loss of body potassium related to muscle atrophy and low dietary intake (2407 +/- 548 mg/day, n=26). Although possibly related to measurement error, the elevations in blood potassium suggest alterations in potassium homeostasis. The space RDA for minimum potassium intake is 3500 mg/day. With the documented inadequate intakes, efforts are being made to increase dietary consumption of potassium.

  13. The influence of a-site-deficiency on the performance of strontium doped lanthanum-manganate perovskite type SOFC-cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Weber, A.; Ivers-Tiffee, E. [Univ. Karlsruhe, Karlsruhe (Germany); Waser, R. [RWTH Aachen Univ. of Technology, Aachen (Germany); Maenner, R.; Jobst, B.; Schiele, M.; Cerva, H. [Siemens AG, Munich (Germany)

    1996-11-01

    SOFC-cathodes of composition La{sub 80.8-x})Sr{sub 0.2}MnO{sub 3} (LMS) with different La-deficiency X (X=0; 0,05; 0.075 and 0.1) were investigated. The LSM-powders and the sintered cathode layers were analysed by several analytical methods (XRD, SEM, TEM, ICP-OES, ICP-MS, EDX/TEM, HREM and EPMA). The electrical properties of the cathodes were determined by electrical DC-measurements and AC-impedance-spectroscopy during single cell tests at realistic working conditions. All the cathodes showed a significant decrease of the cathode resistance during the first electrical loading of the cell. With increasing La-deficiency X both the initial cathode resistance and the extent of the reduction decreased. After an operation time of some days, the different cells showed nearly the same cathode-performance. A maximum current density of about 1 A/cm{sup 2} at 0.7 V cell voltage at an operation temperature of 950 deg. C using O{sub 2} as the oxidant and H{sub 2} as the fuel (20 % fuel utilisation) was achieved. The microstructure analysis of the cathode layers before and after operation showed, that the decrease of the cathode resistance was attributed to an alternation process occurring at the cathode/electrolyte interface. In case of the cathode without La-deficiency, a decomposition of a lanthanum-zirconate- (La{sub 2}Zr{sub 2}O{sub 7}) layer between cathode and electrolyte, which emerged during sintering, was observed. (au)

  14. An electrochemical impedance spectroscopic study of the electronic and ionic transport properties of LiCoO2 cathode

    Institute of Scientific and Technical Information of China (English)

    ZHUANG QuanChao; XU JinMei; FAN XiaoYong; DONG QuanFeng; JIANG YanXia; HUANG Ling; SUN ShiGang

    2007-01-01

    The storage behavior and process of the first delithiation-lithiation of LiCoO2 cathode were investigated by electrochemical impedance spectroscopy (EIS). The electronic and ionic transport properties of LiCoO2 cathode along with variation of electrode potential were obtained in 1 mol.L-1 LiPF6-EC: DMC:DEC electrolyte solution. It was found that after 9 h storage of the LiCoO2 cathode in electrolyte solutions, a new arc appears in the medium frequency range in Nyquist plots of ElS, which increases with increasing the storage time. In the charge/discharge processes, the diameter of the new arc is reversibly changed with electrode potential. Such variation coincides well with the electrode potential dependence of electronic conductivity of the LiCoO2. Thus this new ElS feature is attributed to the change of electronic conductivity of LixCoO2 during storage of the LiCoO2 cathode in electrolyte solutions, as well as in processes of intercalation-deintercalationtion of lithium ions. It has been revealed that the reversible increase and decrease of the resistance of SEI film in charge-discharge processes can be also ascribed to the variation of electronic conductance of active materials of the LiCoO2 cathode.

  15. 3-D Flow Field of Cathode Design for NC Precision Electrochemical Machining Integer Impeller Based on CFD

    Directory of Open Access Journals (Sweden)

    Rui Wu

    2011-09-01

    Full Text Available In order to achieve high efficiency and low cost cathode designing, improve stability of process in NC precision electrochemical machining of integer impeller, a method of applying Computational Fluid Dynamics (CFD to aid designing flow field structure of cathode and parameters for NC-ECM has been proposed in this study. The designing of flow field is the key point in cathode design and a suitable flow field design guarantees the process stability in electrochemical machining. A numerical model of the three-dimension flow field was built according to the geometrical model of interelectrode gap and cathode outline. Then the numerical simulation of 3-D flow field was performed by using the standard k-, turbulence model when the turbulence state in electrochemical machining had been determined. The effect of cathode’s structure and initial electrolyte pressure on the electrolyte flow field was analyzed according to the results of numerical simulation. A series of results similar to the actual experimental results are obtained. The method deduced in this paper could be used to achieve high efficiency and low cost cathode design, select of initial electrolyte pressure, and consequently a lot of “trial and error” cycles will be deduced.

  16. A mixed-reactants solid-polymer-electrolyte direct methanol fuel cell

    Science.gov (United States)

    Scott, K.; Shukla, A. K.; Jackson, C. L.; Meuleman, W. R. A.

    Mixed-reactants solid-polymer-electrolyte direct methanol fuel cells (SPE-DMFCs) with a PtRu/C anode and a methanol-tolerant oxygen-reduction cathode catalyst have been assembled and have been subjected to galvanostatic polarisation studies. The oxygen-reduction cathode was either of the FeTMPP/C, CoTMPP/C, FeCoTMPP/C and RuSe/C. It was found that the SPE-DMFC with the RuSe/C cathode yielded the best performance. It has been possible to achieve power densities of approximately 50 and 20 mW/cm 2 while operating a mixed-reactants SPE-DMFC at 90 °C with oxygen and air fed cathodes, respectively. Interestingly, these SPE-DMFCs exhibit no parasitic oxidation of methanol with oxygen.

  17. Effect of Sintering Temperature and Applied Load on Anode-Supported Electrodes for SOFC Application

    Directory of Open Access Journals (Sweden)

    Xuan-Vien Nguyen

    2016-08-01

    Full Text Available Anode-supported cells are prepared by a sequence of hot pressing and co-sintering processes for solid oxide fuel cell (SOFC applications. Commercially available porous anode tape (NiO/YSZ = 50 wt %/50 wt %, anode tape (NiO/YSZ = 30 wt %/70 wt %, and YSZ are used as the anode substrate, anode functional layer, and electrolyte layer, respectively. After hot pressing, the stacked layers are then sintered at different temperatures (1250 °C, 1350 °C, 1400 °C and 1450 °C for 5 h in air. Different compressive loads are applied during the sintering process. An (La,SrMnO3 (LSM paste is coated on the post-sintered anode-supported electrolyte surface as the cathode, and sintered at different temperatures (1100 °C, 1150 °C, 1200 °C and 1250 °C for 2 h in air to generate anode-supported cells with dimensions of 60 × 60 mm2 (active reaction area of 50 × 50 mm2. SEM is used to investigate the anode structure of the anode-supported cells. In addition, confocal laser scanning microscopy is used to investigate the roughness of the cathode surfaces. At sintering temperatures of 1400 °C and 1450 °C, there is significant grain growth in the anode. Furthermore, the surface of the cathode is smoother at a firing temperature of 1200 °C. It is also found that the optimal compressive load of 1742 Pa led to a flatness of 168 µm/6 cm and a deformation of 0.72%. The open circuit voltage and power density of the anode-supported cell at 750 °C were 1.0 V and 178 mW·cm−2, respectively.

  18. A study of tetrabromobisphenol A (TBBA) as a flame retardant additive for Li-ion battery electrolytes

    Science.gov (United States)

    Belov, Dmitry G.; Shieh, D. T.

    2014-02-01

    Electrochemical behavior and flammability of tetrabromobisphenol A (TBBA)-mixed electrolyte solutions are investigated using 1 mol L-1 LiPF6-EC:EMC (1:2 vol.%) with 0 wt.% (reference electrolyte) and 1-3 wt.% of TBBA. The cycling performance (at room and elevated temperature) and rate capability of the 18650 cell (LiMn2O4:Li(Ni1/3Co1/3Mn1/3)O2 (8:2)/Li4Ti5O12) cell containing TBBA-mixed electrolyte is similar to that of cell containing the reference electrolyte. A detailed analysis of the surface on both the anode and the cathode electrodes via X-ray photoelectron spectroscopy (XPS) indicated that the cathode electrode contains more Br components than the anode electrode. Within the first few cycles, on the positive electrode, we observe competing redox processes between the cathode material containing Mn and TBBA, which generate hydroxy radicals and other by-products. This process and the electrochemical reductive decomposition of TBBA to HBr, Br2 and bisphenole A are responsible for the increased flame retardant properties of the electrolyte containing TBBA. Safety tests were performed using an 18650 cell showed that even 1 wt.% of TBBA in the electrolyte significantly reduces cell flammability.

  19. Slurry spin coating of thin film yttria stabilized zirconia/gadolinia doped ceria bi-layer electrolytes for solid oxide fuel cells

    Science.gov (United States)

    Kim, Hyun Joong; Kim, Manjin; Neoh, Ke Chean; Han, Gwon Deok; Bae, Kiho; Shin, Jong Mok; Kim, Gyu-Tae; Shim, Joon Hyung

    2016-09-01

    Thin ceramic bi-layered membrane comprising yttria-stabilized zirconia (YSZ) and gadolinia-doped ceria (GDC) is fabricated by the cost-effective slurry spin coating technique, and it is evaluated as an electrolyte of solid oxide fuel cells (SOFCs). It is demonstrated that the slurry spin coating method is capable of fabricating porous ceramic films by adjusting the content of ethyl-cellulose binders in the source slurry. The porous GDC layer deposited by spin coating under an optimal condition functions satisfactorily as a cathode-electrolyte interlayer in the test SOFC stack. A 2-μm-thick electrolyte membrane of the spin-coated YSZ/GDC bi-layer is successfully deposited as a dense and stable film directly on a porous NiO-YSZ anode support without any interlayers, and the SOFC produces power output over 200 mW cm-2 at 600 °C, with an open circuit voltage close to 1 V. Electrochemical impedance spectra analysis is conducted to evaluate the performance of the fuel cell components in relation with the microstructure of the spin-coated layers.

  20. Preparation of anode-electrolyte structures using graphite, sodium bicarbonate or citric acid as pore forming agents for application in solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Paz Fiuza, Raigenis da; Silva, Marcos Aurelio da; Guedes, Bruna C.; Pontes, Luiz A.; Boaventura, Jaime Soares [UFBA, Salvador, Bahia (Brazil). Energy and Materials Science Group

    2010-07-01

    Cermets based on Ni supported on YSZ or GDC were prepared for use as anode in direct reform SOFCs. NaHCO3 (Na-Ni-YSZ and Na-Ni-GDC) or citric acid (Ac-Ni-YSZ and Ac-Ni-GDC) were used as pore forming agents (PFAs). The SOFC anode was also prepared using graphite (G-Ni-YSZ and G-Ni-GDC) as PFA for the purposes of comparison. The testing unitary SOFC, planar type, was made by pressing the anode-electrolyte assembly, followed by sintering at 1500 C. After this, LSM (lanthanum and strontium manganite) paint was used for the cathode deposition. The powdered cermets were evaluated in ethanol steam reforming at 650 C. The ethanol conversion was 84% and 32% for cermets Na-Ni-YSZ and G-Ni-YSZ, respectively and the selectivity to H{sub 2} was 32 and 20% for the two cermets, respectively. The Na-Ni-YSZ cermet was ten times more resistant to carbon deposition than the G-Ni-YSZ cermet. SEM micrographs of the anode-electrolyte assembly showed that the use of NaHCO{sub 3} as PFA created a well formed interface between layers with homogeneously distributed pores. In contrast, graphite as PFA formed a loose interface between anode and electrolyte. The performance of the unitary SOFC was evaluated using ethanol, hydrogen or methane as fuel. The cell operated well using any of these fuels; however, they exhibited different electrochemical behavior. (orig.)

  1. Effect of ionic conductivity of zirconia electrolytes on polarization properties of various electrodes in SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Masahiro; Uchida, Hiroyuki; Yoshida, Manabu [Yamanashi Univ., Kofu (Japan)

    1996-12-31

    Solid oxide fuel cells (SOFCs) have been intensively investigated because, in principle, their energy conversion efficiency is fairly high. Lowering the operating temperature of SOFCs from 1000{degrees}C to around 800{degrees}C is desirable for reducing serious problems such as physical and chemical degradation of the constructing materials. The object of a series of the studies is to find a clue for achieving higher electrode performances at a low operating temperature than those of the present level. Although the polarization loss at electrodes can be reduced by using mixed-conducting ceria electrolytes, or introducing the mixed-conducting (reduced zirconia or ceria) laver on the conventional zirconia electrolyte surface, no reports are available on the effect of such an ionic conductivity of electrolytes on electrode polarizations. High ionic conductivity of the electrolyte, of course, reduces the ohmic loss. However, we have found that the IR-free polarization of a platinum anode attached to zirconia electrolytes is greatly influenced by the ionic conductivity, {sigma}{sub ion}, of the electrolytes used. The higher the {sigma}{sub ion}, the higher the exchange current density, j{sub 0}, for the Pt anode in H{sub 2} at 800 {approximately} 1000{degrees}C. It was indicated that the H{sub 2} oxidation reaction rate was controlled by the supply rate of oxide ions through the Pt/zirconia interface which is proportional to the {sigma}{sub ion}. Recently, we have proposed a new concept of the catalyzed-reaction layers which realizes both high-performances of anodes and cathodes for medium-temperature operating SOFCs. We present the interesting dependence of the polarization properties of various electrodes (the SDC anodes with and without Ru microcatalysts, Pt cathode, La(Sr)MnO{sub 3} cathodes with and without Pt microcatalysts) on the {sigma}{sub ion} of various zirconia electrolytes at 800 {approximately} 1000{degrees}C.

  2. Polymer membrane based electrolytic cell and process for the direct generation of hydrogen peroxide in liquid streams

    Science.gov (United States)

    White, James H. (Inventor); Schwartz, Michael (Inventor); Sammells, Anthony F. (Inventor)

    1997-01-01

    An electrolytic cell for generating hydrogen peroxide is provided including a cathode containing a catalyst for the reduction of oxygen, and an anode containing a catalyst for the oxidation of water. A polymer membrane, semipermeable to either protons or hydroxide ions is also included and has a first face interfacing to the cathode and a second face interfacing to the anode so that when a stream of water containing dissolved oxygen or oxygen bubbles is passed over the cathode and a stream of water is passed over the anode, and an electric current is passed between the anode and the cathode, hydrogen peroxide is generated at the cathode and oxygen is generated at the anode.

  3. Endurance testing with Li/Na electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Ong, E.T.; Remick, R.J.; Sishtla, C.I. [Institute of Gas Technology, Des Plaines, IL (United States)

    1996-12-31

    The Institute of Gas Technology (IGT), under subcontract to M-C Power Corporation under DOE funding, has been operating bench-scale fuel cells to investigate the performance and endurance issues of the Li/Na electrolyte because it offers higher ionic conductivity, higher exchange current densities, lower vapor pressures, and lower cathode dissolution rates than the Li/K electrolyte. These cells have continued to show higher performance and lower decay rates than the Li/K cells since the publication of our two previous papers in 1994. In this paper, test results of two long-term 100-cm{sup 2} bench scale cells are discussed. One cell operated continuously at 160 mA/cm{sup 2} for 17,000 hours with reference gases (60H{sub 2}/20CO{sub 2}/20H{sub 2}O fuel at 75% utilization and 30CO{sub 2}/70 air oxidant humidified at room temperature at 50% utilization). The other cell operated at 160 mA/cm{sup 2} for 6900 hours at 3 atm with system gases (64H{sub 2}/16CO{sub 2}/20H{sub 2}O at 75% utilization and an M-C Power system-defined oxidant at 40% utilization). Both cells have shown the highest performance and longest endurance among IGT cells operated to date.

  4. Mathematical modeling of polymer electrolyte fuel cells

    Science.gov (United States)

    Sousa, Ruy; Gonzalez, Ernesto R.

    Fuel cells with a polymer electrolyte membrane have been receiving more and more attention. Modeling plays an important role in the development of fuel cells. In this paper, the state-of-the-art regarding modeling of fuel cells with a polymer electrolyte membrane is reviewed. Modeling has allowed detailed studies concerning the development of these cells, e.g. in discussing the electrocatalysis of the reactions and the design of water-management schemes to cope with membrane dehydration. Two-dimensional models have been used to represent reality, but three-dimensional models can cope with some important additional aspects. Consideration of two-phase transport in the air cathode of a proton exchange membrane fuel cell seems to be very appropriate. Most fuel cells use hydrogen as a fuel. Besides safety concerns, there are problems associated with production, storage and distribution of this fuel. Methanol, as a liquid fuel, can be the solution to these problems and direct methanol fuel cells (DMFCs) are attractive for several applications. Mass transport is a factor that may limit the performance of the cell. Adsorption steps may be coupled to Tafel kinetics to describe methanol oxidation and methanol crossover must also be taken into account. Extending the two-phase approach to the DMFC modeling is a recent, important point.

  5. Understanding the interfacial phenomena of a 4.7 V and 55 °C Li-ion battery with Li-rich layered oxide cathode and grap2hite anode and its correlation to high-energy cycling performance

    Science.gov (United States)

    Pham, Hieu Quang; Hwang, Eui-Hyung; Kwon, Young-Gil; Song, Seung-Wan

    2016-08-01

    Research progress of high-energy performance and interfacial phenomena of Li1.13Mn0.463Ni0.203Co0.203O2 cathode and graphite anode in a 55 °C full-cell under an aggressive charge cut-off voltage to 4.7 V (4.75 V vs. Li/Li+) is reported. Although anodic instability of conventional electrolyte is the critical issue on high-voltage and high-temperature cell operation, interfacial phenomena and the solution to performance improvement have not been reported. Surface spectroscopic evidence revealed that structural degradation of both cathode and anode materials, instability of surface film at cathode, and metal-dissolution from cathode and -deposition at anode, and a rise of interfacial resistance with high-voltage cycling in 55 °C conventional electrolyte are resolved by the formation of a stable surface film with organic/inorganic mixtures at cathode and solid electrolyte interphase (SEI) at anode using blended additives of fluorinated linear carbonate and vinylene carbonate. As a result, significantly improved cycling stability of 77% capacity retention delivering 227-174 mAhg-1 after 50 cycles is obtained, corresponding to 819-609 Wh per kg of cathode active material. Interfacial stabilization approach would pave the way of controlling the performance and safety, and widening the practical application of Li-rich layered oxide cathode materials and high-voltage electrolyte materials in various high-energy density Li-ion batteries.

  6. Seebeck effect in electrolytes.

    Science.gov (United States)

    Chikina, I; Shikin, V; Varlamov, A A

    2012-07-01

    We study Seebeck effect in liquid electrolytes, starting from its simple neutral analog--thermodiffusion (so-called Ludwig-Soret or Soret effect). It is observed that when two or more subsystems of mobile particles are subjected to the temperature gradient, various types of them respond to it differently. In the case when these fractions, with different mobility parameters (Soret coefficients), are oppositely charged (a case typical for electrolytes), the nonhomogeneous internal electric field is generated. The latter field prevents these fractions from space separation and determines the intensity of the appearing Seebeck effect.

  7. Investigations of oxygen reduction reactions in non-aqueous electrolytes and the lithium-air battery

    Science.gov (United States)

    O'Laoire, Cormac Micheal

    -air battery. Towards this end, using either tetrabutylammonium hexafluorophosphate (TBAPF6) or lithium hexafluorophosphate (LiPF6) electrolyte solutions in four different solvents, namely, dimethyl sulfoxide (DMSO), acetonitrile (MeCN), dimethoxyethane (DME), and tetraethylene glycol dimethyl ether (TEGDME), possessing a range of properties, we have determined that the solvent and the supporting electrolyte cations in the solution act in concert to influence the nature of reduction products and their rechargeability. In solutions containing TBA +, O2 reduction is a highly reversible one-electron process involving the O2/O2- couple in all of the electrolytes examined with little effect on the nature of the solvent. On the other hand, in Li+-containing electrolytes relevant to the Li-air battery, O2 reduction proceeds in a stepwise fashion to form O2-, O22- and O2- as products. These reactions in presence of Li+ are irreversible or quasi-reversible electrochemical processes and the solvents have significant influence on the kinetics, and reversibility or lack thereof, of the different reduction products. Reversible reduction of O2 to long-lived superoxide in a Li+-conducting electrolyte in DMSO has been shown for the first time here. Chapter 5 is the culmination of the thesis where the practical application of the work is demonstrated. We designed electrolytes that facilitate Li-Air rechargeability, by applying the knowledge gained from chapters 2-4. A rechargeable Li-air cell utilizing an electrolyte composed of a solution of LiPF6 in tetraethylene glycol dimethyl ether, CH3O(CH2CH 2O)4CH3 was designed, built and its performance studied. It was shown that the cell yields high capacity and can be recharged in spite the absence of catalyst in the carbon cathode. The application of X-ray diffraction to identify these products formed in a porous carbon electrode is shown here for the first time. The rechargeability of the cell was investigated by repeated charge/discharge cycling

  8. Hollow Cathode With Multiple Radial Orifices

    Science.gov (United States)

    Brophy, John R.

    1992-01-01

    Improved hollow cathode serving as source of electrons has multiple radial orifices instead of single axial orifice. Distributes ion current more smoothly, over larger area. Prototype of high-current cathodes for ion engines in spacecraft. On Earth, cathodes used in large-diameter ion sources for industrial processing of materials. Radial orientation of orifices in new design causes current to be dispersed radially in vicinity of cathode. Advantageous where desireable to produce plasma more nearly uniform over wider region around cathode.

  9. Fabrication and performance of La0.8Sr0.2MnO3/YSZ graded composite cathodes for SOFC

    Institute of Scientific and Technical Information of China (English)

    SUN Kening; PIAO Jinhua; ZHANG Naiqing; CHEN Xinbing; XU Shen; ZHOU Derui

    2008-01-01

    The performance of multi-layer (1-x)La0.8Sr0.2MnO3/xYSZ graded composite cathodes was studied as electrode materials for intermediate solid oxide fuel cells (SOFC). The thermal expansion coefficient, electrical conductivity, and electrochemical performance of multi-layer composite cathodes were investigated. The thermal expansion coefficient and electrical conductivity decreased with the increase in YSZ content. The (1-x)La0.8Sr0.2MnO3/xYSZ composite cathode greatly increased the length of the active triple phase boundary line (TPBL) among electrode, electrolyte, and gas phase, leading to a decrease in polarization resistance and an increase in polarization current density. The polarization current density of the triple-layer graded composite cathode (0.77 A/cm2) was the highest and that of the monolayer cathode (0.13 A/cm2) was the lowest. The polarization resistance (Rp) of the triple-layer graded composite cathode was only 0.182Ω·cm2 and that of the monolayer composite cathode was 0.323Ω·cm2. The power density of the triple-layer graded composite cathode was the highest and that of the monolayer composite cathode was the lowest. The triple-layer graded composite cathode had superior performance.

  10. Mechanism of the carbonate-based-electrolyte degradation and its effects on the electrochemical performance of Li1+x(NiaCobMn1-a-b)1-xO2 cells

    Science.gov (United States)

    Peng, H.-J.; Villevieille, C.; Trabesinger, S.; Wolf, H.; Leitner, K.; Novák, P.

    2016-12-01

    In lithium-ion batteries with carbonate electrolytes, the formation of lithium alkoxides at the anode impairs the electrochemical performance and the cycle life of the cells through destabilisation of the cathode-electrolyte interface. To fully understand the effect of electrolyte composition on the stability of the cathode-electrolyte interface, and therefore to minimise alkoxide formation and improve cycling stability, we study different carbonate solvents and mixtures thereof. Electrolytes that promote the formation of ethoxide are found to be more detrimental to the cell performance than those forming methoxide. The presence of cyclic carbonates in the electrolyte-solvent mixture alleviates the detrimental effects of ethoxide-forming solvents on the electrochemical performance of Li1.05(Ni0.33Co0.33Mn0.33)0.95O2 by reducing the solubility of the ethoxide.

  11. Foaming-electrolyte fuel cell

    Science.gov (United States)

    Nanis, L.; Saunders, A. P.

    1970-01-01

    Foam structure feeds fuel gas solution into electrolyte. Fuel gas reacts at static, three-phase interface between fuel gas, electrolyte, and electrode material. The foam forms an electrical contact between main body of electrolyte and the electrode, and aids in removal of by-products of the chemical reaction.

  12. Analysis of SEI formed with cyano-containing imidazolium-based ionic liquid electrolyte in lithium secondary batteries

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Liwei; Yamaki, Jun-ichi [Institute for Materials Chemistry and Engineering, Kyushu University, 6-1 Kasuga-Koen, Kasuga, Fukuoka 816-8580 (Japan); Egashira, Minato [Department of Applied Chemistry and Chemical Engineering, Faculty of Engineering, Yamaguchi University, 2-16-1, Yamaguchi 755-8611 (Japan)

    2007-12-06

    Two kinds of cyano-containing imidazolium-based ionic liquid, 1-cyanopropyl-3-methylimidazolium-bis(trifluoromethanesulfonyl)imide (CpMI-TFSI) and 1-cyanomethyl-3-methylimidazolium-bis(trifluoromethanesulfonyl)imide (CmMI-TFSI), each of which contained 20 wt% dissolved LiTFSI, were used as electrolytes for lithium secondary batteries. Compared with 1-ethyl-3-methylimidazolium-bis(trifluoromethane-sulfonyl)imide (EMI-TFSI) electrolyte, a reversible lithium deposition/dissolution on a stainless-steel working electrode was observed during CV measurements in these cyano-containing electrolytes, which indicated that a passivation layer (solid electrolyte interphase, SEI) was formed during potential scanning. The morphology of the working electrode with each electrolyte system was studied by SEM. Different dentrite forms were found on the electrodes with each electrolyte. The SEI that formed in CpMI-TFSI electrolyte showed the best passivating effect, while the deposited film formed in EMI-TFSI electrolyte showed no passivating effect. The chemical characteristics of the deposited films on the working electrodes were compared by XPS measurements. A component with a cyano group was found in SEIs in CpMI-TFSI and CmMI-TFSI electrolytes. The introduction of a cyano functional group suppressed the decomposition of electrolyte and improved the cathodic stability of the imidazolium-based ionic liquid. The reduction reaction route of imidazolium-based ionic liquid was considered to be different depending on whether or not the molecular structure contained a cyano functional group. (author)

  13. Lead oxides as cathode materials for voltage-compatible lithium cells

    Energy Technology Data Exchange (ETDEWEB)

    Peraldo Bicelli, L.; Rivolta, B.; Bonino, F.; Maffi, S.; Malitesta, C.

    1986-06-01

    Yellow ..beta..-PbO (massicot) and ..beta..-PbO/sub 2/ (plattnerite) have been investigated as cathode materials in organic electrolyte lithium cells. The main characteristics and performance of these cells have been examined and the discharge mechanism discussed on the basis of X-ray data. The two oxides are particularly interesting as candidates for voltage-compatible lithium cells. They exhibit long voltage plateaux of appropriate values and appreciable specific capacities and energies.

  14. Catalysts for ultrahigh current density oxygen cathodes for space fuel cell applications

    Science.gov (United States)

    Tryk, Donald A.; Yeager, E.

    1992-01-01

    The objective was to identify promising electrocatalyst/support systems for oxygen cathodes capable of operating at ultrahigh current densities in alkaline fuel cells. Such cells will require operation at relatively high temperatures and O2 pressures. A number of materials were prepared, including Pb-Ru and Pb-Ir pyrochlores, RuO2 and Pt-doped RuO2, lithiated NiO and La-Ni perovskites. Several of these materials were prepared using techniques that had not been previously used to prepare them. Particularly interesting was the use of the alkaline solution technique to prepare Pt-doped and Pb-Ru pyrochlores in high area form. Also interesting was the use of the fusion (melt) method for preparing the Pb-Ru pyrochlore. Several of the materials were also deposited with platinum. Well-crystallized Pb2Ru2O(7-y) was used to fabricate very high performance O2 cathodes with good stability in room temperature KOH. This material was also found to be stable over a useful potential range at approx. 140 C in concentrated KOH. For some of the samples, fabrication of the gas-fed electrodes could not be fully optimized during this project period. Future work may be directed at this problem. Pyrochlores that were not well-crystallized were found to be unstable in alkaline solution. Very good O2 reduction performance and stability were observed with Pb2RuO(7-y) in a carbon-based gas-fed electrode with an anion-conducting membrane placed on the electrolyte side of the electrode. The performance came within a factor of about two of that observed without carbon. High area platinum and gold supported on several conductive metal oxide supports were examined. Only small improvements in O2 reduction performance at room temperature were observed for Pb2Ru2O(7-y) as a support because of the high intrinsic activity of the pyrochlore. In contrast, a large improvement was observed for Li-doped NiO as a support for Pt. Very poor performance was observed for Au deposited on Li-NiO at approx. 150 C

  15. Novel Stable Gel Polymer Electrolyte: Toward a High Safety and Long Life Li-Air Battery.

    Science.gov (United States)

    Yi, Jin; Liu, Xizheng; Guo, Shaohua; Zhu, Kai; Xue, Hailong; Zhou, Haoshen

    2015-10-28

    Nonaqueous Li-air battery, as a promising electrochemical energy storage device, has attracted substantial interest, while the safety issues derived from the intrinsic instability of organic liquid electrolytes may become a possible bottleneck for the future application of Li-air battery. Herein, through elaborate design, a novel stable composite gel polymer electrolyte is first proposed and explored for Li-air battery. By use of the composite gel polymer electrolyte, the Li-air polymer batteries composed of a lithium foil anode and Super P cathode are assembled and operated in ambient air and their cycling performance is evaluated. The batteries exhibit enhanced cycling stability and safety, where 100 cycles are achieved in ambient air at room temperature. The feasibility study demonstrates that the gel polymer electrolyte-based polymer Li-air battery is highly advantageous and could be used as a useful alternative strategy for the development of Li-air battery upon further application.

  16. Advanced Electrolyte/Additive for Lithium-Ion Batteries with Silicon Anode

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Shuo; He, Meinan; Su, Chi-Cheung; Zhang, Zhengcheng

    2016-07-01

    State-of-the-art lithium-ion batteries (LIBs) are based on a lithium transition metal oxide cathode, a graphite anode and a nonaqueous carbonate electrolyte. To further increase the energy and power density of LIBs, silicon anodes have been intensively explored due to their high theoretical capacity, low operation potential, and low cost. However, the main challenges for Si anode are the large volume change during lithiation/delithiation process and the instability of the solid-electrolyte-interphase associated with this process. Recently, significant progress has been achieved via advanced material fabrication technologies and rational electrolyte design in terms of improving the Coulombic efficiency and capacity retention. In this paper, new developments in advanced electrolyte and additive for LIBs with Si anode were systematically reviewed, and perspectives over future research were suggested.

  17. Use of Thermodynamic Modeling for Selection of Electrolyte for Electrorefining of Magnesium from Aluminum Alloy Melts

    Science.gov (United States)

    Gesing, Adam J.; Das, Subodh K.

    2016-06-01

    With United States Department of Energy Advanced Research Project Agency funding, experimental proof-of-concept was demonstrated for RE-12TM electrorefining process of extraction of desired amount of Mg from recycled scrap secondary Al molten alloys. The key enabling technology for this process was the selection of the suitable electrolyte composition and operating temperature. The selection was made using the FactSage thermodynamic modeling software and the light metal, molten salt, and oxide thermodynamic databases. Modeling allowed prediction of the chemical equilibria, impurity contents in both anode and cathode products, and in the electrolyte. FactSage also provided data on the physical properties of the electrolyte and the molten metal phases including electrical conductivity and density of the molten phases. Further modeling permitted selection of electrode and cell construction materials chemically compatible with the combination of molten metals and the electrolyte.

  18. Use of Thermodynamic Modeling for Selection of Electrolyte for Electrorefining of Magnesium from Aluminum Alloy Melts

    Science.gov (United States)

    Gesing, Adam J.; Das, Subodh K.

    2017-02-01

    With United States Department of Energy Advanced Research Project Agency funding, experimental proof-of-concept was demonstrated for RE-12TM electrorefining process of extraction of desired amount of Mg from recycled scrap secondary Al molten alloys. The key enabling technology for this process was the selection of the suitable electrolyte composition and operating temperature. The selection was made using the FactSage thermodynamic modeling software and the light metal, molten salt, and oxide thermodynamic databases. Modeling allowed prediction of the chemical equilibria, impurity contents in both anode and cathode products, and in the electrolyte. FactSage also provided data on the physical properties of the electrolyte and the molten metal phases including electrical conductivity and density of the molten phases. Further modeling permitted selection of electrode and cell construction materials chemically compatible with the combination of molten metals and the electrolyte.

  19. Microhollow cathode discharges

    Science.gov (United States)

    Schoenbach, K. H.; Moselhy, M.; Shi, W.; Bentley, R.

    2003-07-01

    By reducing the dimensions of hollow cathodes into the hundred micrometer range, stable, direct current, high (atmospheric) pressure glow discharges in rare gases, rare gas-halide mixtures and in air could be generated. The electron energy distribution in these microdischarges is non-Maxwellian, with a pronounced high-energy tail. The high electron energy together with the high gas density, which favors three-body collisions, is the reason for an efficient excimer generation in these microplasmas. Excimer efficiencies from 1% to 9% have been measured for argon, xenon, argon fluoride, and xenon chloride direct current excimer emitters, with a radiant excimer emittance of up to 2 W/cm2 for xenon. Adding small amounts of oxygen to argon has allowed us to generate vacuum ultraviolet line radiation at 130.5 nm with an efficiency approaching 1%. Pulsing xenon discharges with nanosecond electrical pulses has led to an increase in intensity to 15 W/cm2 and to a simultaneous increase in efficiency to more than 20%. Operating the discharges in an abnormal glow mode has allowed us to generate microdischarge arrays without individual ballast. Applications of these plasma arrays are excimer lamps and plasma reactors.

  20. Synthesis of tetramethyl ammonium hydroxide by cell diaphragm electrolytic method

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Under the conditions of tetramethyl ammonia chloride (TMAC) used as starting material, Ti-based Dimensionally Stable Anode (DSA), stainless steel used as cathode and Nafion 900 cation membrane as cell diaphragm, this paper studies the synthesis of tetramethyl ammonium hydroxide (TMAH) by cell diaphragm electrolytic method, examining not only the effects of current density, concentration of starting material and cell temperature, on the product purity and current efficiency, but also the effects of electrolyte circulation rate on the service life of Ti-based DSA.The experiment puts forward an optimum processing condition, and experimental findings show that preparing TMAH by using this technique can obtain a current efficiency 74.7 % and get product with a purity greater than 99.9%.

  1. Development of a new electrolyte matrix for MCFC

    Energy Technology Data Exchange (ETDEWEB)

    Nagashima, I.; Higaki, K.; Terada, S.; Suemitsu, T. [Akashi Technical Institute (Japan)

    1996-12-31

    To prolong the life of cell is one of the most important issues for MCFC to be brought into actual application. In this respect, investigators have been proposing the addition of tungstate salt such as K2WO4 into MCFC electrolyte, which is supposed effectively to reduce the sintering of anode probably by precipitates formed through the reduction of tungstate with dissolved hydrogen near the anode surface. In this research, such effect upon sintering of anode was quantitatively examined by out-of-cell tests and the validity of above assumption for the mechanism was confirmed. Also other effects of tungstate salt addition into electrolyte, such upon corrosion of separator, solubility of cathode, stability of matrix substrates (LiAlO{sub 2}) were investigated.

  2. Composite Cathode Bi1.14Sr0.43O2.14-Ag for Intermediate-temperature Solid Oxide Fuel Cells

    Institute of Scientific and Technical Information of China (English)

    GAO Zhan; ZHANG Ping; GAO Ruifeng; HUANG Jianbing; MAO Zongqiang

    2008-01-01

    Composites consisting of strontium stabilized bismuth oxide (Bi1.14Sr0.43O2.14 SSB) and silver were investigated as cathodes for intermediate-temperature solid oxide fuel cells with doped ceria electrolyte. There were no chemical reactions between the two components. The microstructure of the interfaces between composite cathodes and Ce0.8Sm0.2O1.9 (SDC) electrolytes was examined by scanning electron microscopy (SEM). Impedance spectroscopy measurements show that the performance of cathode fired at 700℃ is the best. When the content of Ag2O is 70wt%, polarization resistance values for the SSB-Ag cathodes are as low as 0.2Ωcm2 at 700℃ and 0.29Ωcm2 at 650℃. These results are much smaller than some of other reported composite cathodes on doped ceria electrolyte and indicate that SSB-Ag composite is a potential cathode material for intermediate temperature SOFCs.

  3. Electrochemical generation of volatile lead species using a cadmium cathode: Comparison with graphite, glassy carbon and platinum cathodes

    Science.gov (United States)

    Sáenz, María; Fernández, Lenys; Domínguez, José; Alvarado, José

    2012-05-01

    Working electrodes made out of pyrolytic graphite, glassy carbon, platinum and cadmium were compared for the electrochemical generation of volatile lead species. The same electrolytic cell, using each of the different working electrodes was coupled to an atomic absorption spectrometer and the experimental conditions were optimized in each case, using a univariate approach, to produce the maximum possible amount of volatile lead species. The experiments were focused on the variation of cathode hydrogen overvoltage by the application of a constant current during analysis. Under optimum conditions the performance of the electrochemical hydride generator cell should depend on the cathode material selected due to the different hydrogen overpotential of each material. The lead absorbance signal was taken as a measure of the efficiency of volatile lead species production. Best results were obtained using the Cd cathode, due to its relatively highest hydrogen overpotential, a carrier gas (Ar) flow rate of 55 mL min- 1 an electrolytic current of 0.8 A and a catholyte (HCl) concentration 0.05 mol L- 1. The analytical figures of merit of the method using the Cd electrode were evaluated and the susceptibility of the method to interferences was assessed by its application to the determination of trace amounts of lead in the presence of the most significant interferents. The calibration curve was linear between 0.5 and 15 μg L- 1 Pb. Detection limits and characteristic mass values were 0.21 μg L- 1 and 0.26 μg L- 1 respectively. A bovine liver standard reference material and a spiked urine sample were analyzed to check accuracy.

  4. Elaboration and characterisation of functionally graded cathodes for solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Simonet, J.; Kapelski, G.; Bouvard, D. [Laboratoire de Genie Physique et Mecanique des Materiaux, Institut National Polytechnique de Grenoble, CNRS UMR 5010, BP 46, 38042 Saint Martin d' Heres cedex (France)

    2005-07-01

    The industrial development of solid oxide fuel cells (SOFC) requires decreasing their operating temperature from 1000 deg. C to 700 deg. C while keeping acceptable mechanical and electrochemical performances. A solution consists in designing composite bulk cathodes with numerous electro-chemical reaction sites. The fabrication of such cathodes has been investigated with classical materials as lanthanum strontium manganese (LSM) and yttrium stabilized zirconia (YSZ), which is also the constitutive material of the electrolyte. A composite cathode with continuous composition gradient has been obtained by co-sedimentation of the powders in a liquid and subsequent firing. The obtained composition is investigated with Scanning Electron Microscope (SEM) and Electron Dispersive Spectrometry (EDS). It is found to be in good agreement with the prediction of a numerical model of the sedimentation process. (authors)

  5. Relevance of cathodic disbondment test for evaluating external pipeline coatings at higher temperature

    Energy Technology Data Exchange (ETDEWEB)

    Papavinasam, S.; Doiron, A.

    2008-09-15

    This study evaluated the applicability of cathodic disbondment (CD) tests at high temperatures. The test is typically used to determine compatibility between external polymeric pipeline coatings and cathodic protection by measuring the disbondment of coatings caused by electrical stresses and evaluating the ability of the coating to not disbond under the stress of cathodic polarization. Factors influencing the applicability of the CD test at higher temperatures were investigated experimentally. The study showed that CD testing can be used for high temperature coating evaluation. Evaporation should be avoided by refluxing or replenishing electrolytes during the experimental process in order to accurately simulate the operating conditions of hot pipes. The study also demonstrated that the thickness and thermal conductivity of a pipeline coating can influence how much heat is transmitted from a pipe section to the surrounding soil. 22 refs., 5 tabs., 16 figs.

  6. Lithium-ion transport in inorganic solid state electrolyte

    Science.gov (United States)

    Jian, Gao; Yu-Sheng, Zhao; Si-Qi, Shi; Hong, Li

    2016-01-01

    An overview of ion transport in lithium-ion inorganic solid state electrolytes is presented, aimed at exploring and designing better electrolyte materials. Ionic conductivity is one of the most important indices of the performance of inorganic solid state electrolytes. The general definition of solid state electrolytes is presented in terms of their role in a working cell (to convey ions while isolate electrons), and the history of solid electrolyte development is briefly summarized. Ways of using the available theoretical models and experimental methods to characterize lithium-ion transport in solid state electrolytes are systematically introduced. Then the various factors that affect ionic conductivity are itemized, including mainly structural disorder, composite materials and interface effects between a solid electrolyte and an electrode. Finally, strategies for future material systems, for synthesis and characterization methods, and for theory and calculation are proposed, aiming to help accelerate the design and development of new solid electrolytes. Project supported by the National Natural Science Foundation of China (Grant No. 51372228), the Shanghai Pujiang Program, China (Grant No. 14PJ1403900), and the Shanghai Institute of Materials Genome from the Shanghai Municipal Science and Technology Commission, China (Grant No. 14DZ2261200).

  7. The influence of cathode material on electrochemical degradation of trichloroethylene in aqueous solution.

    Science.gov (United States)

    Rajic, Ljiljana; Fallahpour, Noushin; Podlaha, Elizabeth; Alshawabkeh, Akram

    2016-03-01

    In this study, different cathode materials were evaluated for electrochemical degradation of aqueous phase trichloroethylene (TCE). A cathode followed by an anode electrode sequence was used to support reduction of TCE at the cathode via hydrodechlorination (HDC). The performance of iron (Fe), copper (Cu), nickel (Ni), aluminum (Al) and carbon (C) foam cathodes was evaluated. We tested commercially available foam materials, which provide large electrode surface area and important properties for field application of the technology. Ni foam cathode produced the highest TCE removal (68.4%) due to its high electrocatalytic activity for hydrogen generation and promotion of HDC. Different performances of the cathode materials originate from differences in the bond strength between atomic hydrogen and the material. With a higher electrocatalytic activity than Ni, Pd catalyst (used as cathode coating) increased TCE removal from 43.5% to 99.8% for Fe, from 56.2% to 79.6% for Cu, from 68.4% to 78.4% for Ni, from 42.0% to 63.6% for Al and from 64.9% to 86.2% for C cathode. The performance of the palladized Fe foam cathode was tested for degradation of TCE in the presence of nitrates, as another commonly found groundwater species. TCE removal decreased from 99% to 41.2% in presence of 100 mg L(-1) of nitrates due to the competition with TCE for HDC at the cathode. The results indicate that the cathode material affects TCE removal rate while the Pd catalyst significantly enhances cathode activity to degrade TCE via HDC.

  8. Gel polymer electrolytes for batteries

    Science.gov (United States)

    Balsara, Nitash Pervez; Eitouni, Hany Basam; Gur, Ilan; Singh, Mohit; Hudson, William

    2014-11-18

    Nanostructured gel polymer electrolytes that have both high ionic conductivity and high mechanical strength are disclosed. The electrolytes have at least two domains--one domain contains an ionically-conductive gel polymer and the other domain contains a rigid polymer that provides structure for the electrolyte. The domains are formed by block copolymers. The first block provides a polymer matrix that may or may not be conductive on by itself, but that can soak up a liquid electrolyte, thereby making a gel. An exemplary nanostructured gel polymer electrolyte has an ionic conductivity of at least 1.times.10.sup.-4 S cm.sup.-1 at 25.degree. C.

  9. Spray deposition of Nafion membranes: Electrode-supported fuel cells

    Science.gov (United States)

    Bayer, Thomas; Pham, Hung Cuong; Sasaki, Kazunari; Lyth, Stephen Matthew

    2016-09-01

    Fuel cells are a key technology for the successful transition towards a hydrogen society. In order to accelerate fuel cell commercialization, improvements in performance are required. Generally, polymer electrolyte membrane fuel cells (PEFCs) are membrane-supported; the electrocatalyst layer is sprayed onto both sides of the membrane, and sandwiched between carbon-based gas diffusion layers (GDLs). In this work we redesign the membrane electrode assembly (MEA) and fabricate an electrode-supported PEFC. First the electrocatalyst layer is sprayed onto the GDL, and then Nafion dispersion is sprayed over the top of this to form a thin membrane. This method has the advantage of simplifying the fabrication process, allowing the fabrication of extremely thin electrolyte layers (down to ∼10 μm in this case), and reducing the amount of ionomer required in the cell. Electrode-supported PEFCs operate at significantly increased power density compared to conventional membrane-supported PEFCs, with a maximum of 581 mW/cm2 at 80 °C (atmospheric pressure, air at the cathode). Impedance spectroscopy confirmed that the origin of the improved performance was an 80% reduction in the membrane resistance due the thinner Nafion layer. This novel fabrication method is a step towards cheaper, thinner, fully printable PEFCs with high power density and efficiency.

  10. Nanostructured carbon electrocatalyst supports for intermediate-temperature fuel cells: Single-walled versus multi-walled structures

    Science.gov (United States)

    Papandrew, Alexander B.; Elgammal, Ramez A.; Tian, Mengkun; Tennyson, Wesley D.; Rouleau, Christopher M.; Puretzky, Alexander A.; Veith, Gabriel M.; Geohegan, David B.; Zawodzinski, Thomas A.

    2017-01-01

    It is unknown if nanostructured carbons possess the requisite electrochemical stability to be used as catalyst supports in the cathode of intermediate-temperature solid acid fuel cells (SAFCs) based on the CsH2PO4 electrolyte. To investigate this application, single-walled carbon nanohorns (SWNHs) and multi-walled carbon nanotubes (MWNTs) were used as supports for Pt catalysts in SAFCs operating at 250 °C. SWNH-based cathodes display greater maximum activity than their MWNT-based counterparts at a cell voltage of 0.8 V, but are unstable in the SAFC cathode as a consequence of electrochemical carbon corrosion. MWNT-based cells are resistant to this effect and capable of operation for at least 160 h at 0.6 V and 250 °C. Cells fabricated with nanostructured carbon supports are more active (52 mA cm-1vs. 28 mA cm-1 at 0.8 V) than state-of-the-art carbon-free formulations while simultaneously displaying enhanced Pt utilization (40 mA mgPt-1vs. 16 mA mgPt-1 at 0.8 V). These results suggest that MWNTs are a viable support material for developing stable, high-performance, low-cost air electrodes for solid-state electrochemical devices operating above 230 °C.

  11. Copper-mercury film electrode for cathodic stripping voltammetric determination of Se(IV).

    Science.gov (United States)

    Sladkov, Vladimir; David, François; Fourest, Blandine

    2003-01-01

    The copper-mercury film electrode has been suggested for the determination of Se(IV) in a wide range of concentration from 1x10(-9) to 1x10(-6) mol L(-1)by square-wave cathodic stripping voltammetry. Insufficient reproducibility and sensitivity of the mercury film electrode have been overcome by using copper(II) ions during the plating procedure. Copper(II) has been found to be reduced and form a reproducible copper-mercury film on a glassy carbon electrode surface. The plating potential and time, the concentration of copper(II) and the concentration of the supporting electrolyte have been optimised. Microscopy has been used for a study of the morphology of the copper-mercury film. It has been found that it is the same as for the mercury one. The preconcentration step consists in electrodeposition of copper selenide on the copper-mercury film. The relative standard deviation is 4.3% for 1x10(-6) mol L(-1) of Se(IV). The limit of detection is 8x10(-10) mol L(-1) for 5 min of accumulation.

  12. Material and Energy Flows in the Production of Cathode and Anode Materials for Lithium Ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, Jennifer B. [Argonne National Lab. (ANL), Argonne, IL (United States); James, Christine [Michigan State Univ., East Lansing, MI (United States); Gaines, Linda [Argonne National Lab. (ANL), Argonne, IL (United States); Gallagher, Kevin [Argonne National Lab. (ANL), Argonne, IL (United States); Dai, Qiang [Argonne National Lab. (ANL), Argonne, IL (United States); Kelly, Jarod C. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-09-01

    The Greenhouse gases, Regulated Emissions and Energy use in Transportation (GREET) model has been expanded to include four new cathode materials that can be used in the analysis of battery-powered vehicles: lithium nickel cobalt manganese oxide (LiNi0.4Co0.2Mn0.4O2 [NMC]), lithium iron phosphate (LiFePO4 [LFP]), lithium cobalt oxide (LiCoO2 [LCO]), and an advanced lithium cathode (0.5Li2MnO3∙0.5LiNi0.44Co0.25Mn0.31O2 [LMR-NMC]). In GREET, these cathode materials are incorporated into batteries with graphite anodes. In the case of the LMR-NMC cathode, the anode is either graphite or a graphite-silicon blend. Lithium metal is also an emerging anode material. This report documents the material and energy flows of producing each of these cathode and anode materials from raw material extraction through the preparation stage. For some cathode materials, we considered solid state and hydrothermal preparation methods. Further, we used Argonne National Laboratory’s Battery Performance and Cost (BatPaC) model to determine battery composition (e.g., masses of cathode, anode, electrolyte, housing materials) when different cathode materials were used in the battery. Our analysis concluded that cobalt- and nickel-containing compounds are the most energy intensive to produce.

  13. Material and Energy Flows in the Production of Cathode and Anode Materials for Lithium Ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, Jennifer B. [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division; James, Christine [Michigan State Univ., East Lansing, MI (United States). Chemical Engineering and Materials Science Dept.; Gaines, Linda G. [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division; Gallagher, Kevin [Argonne National Lab. (ANL), Argonne, IL (United States). Chemical Sciences and Engineering Division

    2014-09-30

    The Greenhouse gases, Regulated Emissions and Energy use in Transportation (GREET) model has been expanded to include four new cathode materials that can be used in the analysis of battery-powered vehicles: lithium nickel cobalt manganese oxide (LiNi0.4Co0.2Mn0.4O2 [NMC]), lithium iron phosphate (LiFePO4 [LFP]), lithium cobalt oxide (LiCoO2 [LCO]), and an advanced lithium cathode (0.5Li2MnO3∙0.5LiNi0.44Co0.25Mn0.31O2 [LMR-NMC]). In GREET, these cathode materials are incorporated into batteries with graphite anodes. In the case of the LMR-NMC cathode, the anode is either graphite or a graphite-silicon blend. This report documents the material and energy flows of producing each of these cathode and anode materials from raw material extraction through the preparation stage. For some cathode materials, we considered solid state and hydrothermal preparation methods. Further, we used Argonne National Laboratory’s Battery Performance and Cost (BatPaC) model to determine battery composition (e.g., masses of cathode, anode, electrolyte, housing materials) when different cathode materials were used in the battery. Our analysis concluded that cobalt- and nickel-containing compounds are the most energy intensive to produce.

  14. POLYMER ELECTROLYTE MEMBRANE FUEL CELLS

    DEFF Research Database (Denmark)

    2001-01-01

    A method for preparing polybenzimidazole or polybenzimidazole blend membranes and fabricating gas diffusion electrodes and membrane-electrode assemblies is provided for a high temperature polymer electrolyte membrane fuel cell. Blend polymer electrolyte membranes based on PBI and various...... thermoplastic polymers for high temperature polymer electrolyte fuel cells have also been developed. Miscible blends are used for solution casting of polymer membranes (solid electrolytes). High conductivity and enhanced mechanical strength were obtained for the blend polymer solid electrolytes...... electrolyte membrane by hot-press. The fuel cell can operate at temperatures up to at least 200 °C with hydrogen-rich fuel containing high ratios of carbon monoxide such as 3 vol% carbon monoxide or more, compared to the carbon monoxide tolerance of 10-20 ppm level for Nafion$m(3)-based polymer electrolyte...

  15. Poly(vinyl alcohol) separators improve the coulombic efficiency of activated carbon cathodes in microbial fuel cells

    KAUST Repository

    Chen, Guang

    2013-09-01

    High-performance microbial fuel cell (MFC) air cathodes were constructed using a combination of inexpensive materials for the oxygen reduction cathode catalyst and the electrode separator. A poly(vinyl alcohol) (PVA)-based electrode separator enabled high coulombic efficiencies (CEs) in MFCs with activated carbon (AC) cathodes without significantly decreasing power output. MFCs with AC cathodes and PVA separators had CEs (43%-89%) about twice those of AC cathodes lacking a separator (17%-55%) or cathodes made with platinum supported on carbon catalyst (Pt/C) and carbon cloth (CE of 20%-50%). Similar maximum power densities were observed for AC-cathode MFCs with (840 ± 42 mW/m2) or without (860 ± 10 mW/m2) the PVA separator after 18 cycles (36 days). Compared to MFCs with Pt-based cathodes, the cost of the AC-based cathodes with PVA separators was substantially reduced. These results demonstrated that AC-based cathodes with PVA separators are an inexpensive alternative to expensive Pt-based cathodes for construction of larger-scale MFC reactors. © 2013 Elsevier B.V. All rights reserved.

  16. Formation of metal oxides by cathodic arc deposition

    Energy Technology Data Exchange (ETDEWEB)

    Anders, S.; Anders, A.; Rubin, M.; Wang, Z.; Raoux, S.; Kong, F.; Brown, I.G.

    1995-03-01

    Metal oxide thin films are of interest for a number of applications. Cathodic arc deposition, an established, industrially applied technique for formation of nitrides (e.g. TiN), can also be used for metal oxide thin film formation. A cathodic arc plasma source with desired cathode material is operated in an oxygen atmosphere, and metal oxides of various stoichiometric composition can be formed on different substrates. We report here on a series of experiments on metal oxide formation by cathodic arc deposition for different applications. Black copper oxide has been deposited on ALS components to increase the radiative heat transfer between the parts. Various metal oxides such as tungsten oxide, niobium oxide, nickel oxide and vanadium oxide have been deposited on ITO glass to form electrochromic films for window applications. Tantalum oxide films are of interest for replacing polymer electrolytes. Optical waveguide structures can be formed by refractive index variation using oxide multilayers. We have synthesized multilayers of Al{sub 2}O{sub 3}/Y{sub 2}O{sub 3}/AI{sub 2}O{sub 3}/Si as possible basic structures for passive optoelectronic integrated circuits, and Al{sub 2-x}Er{sub x}O{sub 3} thin films with a variable Er concentration which is a potential component layer for the production of active optoelectronic integrated devices such as amplifiers or lasers at a wavelength of 1.53 {mu}m. Aluminum and chromium oxide films have been deposited on a number of substrates to impart improved corrosion resistance at high temperature. Titanium sub-oxides which are electrically conductive and corrosion resistant and stable in a number of aggressive environments have been deposited on various substrates. These sub-oxides are of great interest for use in electrochemical cells.

  17. ICCP cathodic protection of tanks with photovoltaic power supply

    Directory of Open Access Journals (Sweden)

    Janowski Mirosław

    2016-01-01

    Full Text Available Corrosion is the result of the electrochemical reaction between a metal or composite material usually having conducting current properties. Control of corrosion related defect is a very important problem for structural integrity in ground based structures. Cathodic protection (CP is a technique to protect metallic structures against corrosion in an aqueous environment, it is employed intense on the steel drains in oil and gas industry, specifically to protect underground tanks and pipelines. CP is commonly applied to a coated structure to provide corrosion control to areas where the coating may be damaged. It may be applied to existing structures to prolong their life. There are two types of cathodic protection systems: sacrificial (galvanic anode cathodic protection (SACP; the other system is Impressed Current Cathodic Protection (ICCP. Majority of the structures protected employ impressed current system. The main difference between the two is that SACP uses the galvanic anodes which are electrochemically more electronegative than the structure to be protected - the naturally occurring electrochemical potential difference between different metallic elements to provide protection; ICCP uses an external power source (electrical generator with D.C. with inert anodes, and this system is used for larger structures, or where electrolyte resistivity is high and galvanic anodes cannot economically deliver enough current to provide protection. The essential of CP is based on two parameters, the evolution of the potential and the current of protection. A commonly accepted protection criterion used for steel is a potential value of minus 850 mV. ICCP system consist of anodes connected to a DC power source. As power sources may be used such as solar panels, wind turbines, etc. The object of this study is analysis of the possibilities and operating parameters of ICCP system supplied with photovoltaic solar panels. Photovoltaic generator made up of the

  18. Electrode-electrolyte BIMEVOX system for moderate temperature oxygen separation

    Energy Technology Data Exchange (ETDEWEB)

    Boivin, J.C.; Pirovano, C.; Nowogrocki, G.; Mairesse, G. [Laboratoire de Cristallochimie et Physicochimie du Solide, URA CNRS 452, USTL-ENSCL BP 108, 59652 Villeneuve d`Ascq (France); Labrune, Ph.; Lagrange, G. [Centre de recherches Claude Delorme, Air Liquide, Jouy en Josas (France)

    1998-12-01

    Electrochemical separation of oxygen from air is a promising application for oxide conductor solid electrolytes. However, several important specifications are required in order to obtain an efficient separation device. First of all, the electrolyte material must exhibit a high conductivity at moderate temperature. From this point of view, a new family of materials called BIMEVOX ideally fulfils this condition. Secondly, a typical separation device must comport two electrodes on opposite faces of the electrolyte. These electrodes must act as electronic collectors but also, at the cathodic side, as an oxygen dissociation catalyst. BIMEVOX electrolytes exhibit ionic conductivity values that can allow work at temperature below 500C. The classical electrode approach, like in solid oxide fuel cells, consists in using a specific mixed oxide, for instance strontium lanthanum manganite or cobaltite. However, the lower the temperature, the lower the efficiency of these electrodes which quickly appears as the limiting factor. In previous work on bismuth lead oxide electrolytes, we proposed a new approach that consists of using the surface of the bismuth-based electrolyte itself as the catalyst, the electron collection being then performed by a co-sintered metallic grid. This `in-situ` electrode system provides many advantages, particularly it eliminates the problem of the chemical compatibility between electrode and electrolyte materials. Taking into account the presence of both catalytic vanadium and bismuth cations in BIMEVOX, we checked under these conditions the separation of oxygen from air for different electrolytes (BICOVOX, BICUVOX, BIZNVOX) at various temperatures in the range 430-600C. For instance, using a BICOVOX pellet with a gold grid inserted on each side makes it possible to separate oxygen with nearly 100% efficiency for current density values up to 1000 mA/cm{sup -2}. For higher intensity values, the faradic efficiency progressively but reversibly decreases

  19. The effect of oxygen transfer mechanism on the cathode performance based on proton-conducting solid oxide fuel cells

    KAUST Repository

    Hou, Jie

    2015-01-01

    Two types of proton-blocking composites, La2NiO4+δ-LaNi0.6Fe0.4O3-δ (LNO-LNF) and Sm0.2Ce0.8O2-δ-LaNi0.6Fe0.4O3-δ (SDC-LNF), were evaluated as cathode materials for proton-conducting solid oxide fuel cells (H-SOFCs) based on the BaZr0.1Ce0.7Y0.2O3-δ (BZCY) electrolyte, in order to compare and investigate the influence of two different oxygen transfer mechanism on the performance of the cathode for H-SOFCs. The X-ray diffraction (XRD) results showed that the chemical compatibility of the components in both compounds was excellent up to 1000°C. Electrochemical studies revealed that LNO-LNF showed lower area specific polarization resistances in symmetrical cells and better electrochemical performance in single cell tests. The single cell with LNO-LNF cathode generated remarkable higher maximum power densities (MPDs) and lower interfacial polarization resistances (Rp) than that with SDC-LNF cathode. Correspondingly, the MPDs of the single cell with the LNO-LNF cathode were 490, 364, 266, 180 mW cm-2 and the Rp were 0.103, 0.279, 0.587, 1.367 Ω cm2 at 700, 650, 600 and 550°C, respectively. Moreover, after the single cell with LNO-LNF cathode optimized with an anode functional layer (AFL) between the anode and electrolyte, the power outputs reached 708 mW cm-2 at 700°C. These results demonstrate that the LNO-LNF composite cathode with the interstitial oxygen transfer mechanism is a more preferable alternative for H-SOFCs than SDC-LNF composite cathode with the oxygen vacancy transfer mechanism.

  20. Electrolytes for Use in High Energy Lithium-ion Batteries with Wide Operating Temperature Range

    Science.gov (United States)

    Smart, Marshall C.; Ratnakumar, B. V.; West, W. C.; Whitcanack, L. D.; Huang, C.; Soler, J.; Krause, F. C.

    2012-01-01

    Met programmatic milestones for program. Demonstrated improved performance with wide operating temperature electrolytes containing ester co-solvents (i.e., methyl butyrate) containing electrolyte additives in A123 prototype cells: Previously demonstrated excellent low temperature performance, including 11C rates at -30 C and the ability to perform well down to -60 C. Excellent cycle life at room temperature has been displayed, with over 5,000 cycles being demonstrated. Good high temperature cycle life performance has also been achieved. Demonstrated improved performance with methyl propionate-containing electrolytes in large capacity prototype cells: Demonstrated the wide operating temperature range capability in large cells (12 Ah), successfully scaling up technology from 0.25 Ah size cells. Demonstrated improved performance at low temperature and good cycle life at 40 C with methyl propionate-based electrolyte containing increasing FEC content and the use of LiBOB as an additive. Utilized three-electrode cells to investigate the electrochemical characteristics of high voltage systems coupled with wide operating temperature range electrolytes: From Tafel polarization measurements on each electrode, it is evident the NMC-based cathode displays poor lithium kinetics (being the limiting electrode). The MB-based formulations containing LiBOB delivered the best rate capability at low temperature, which is attributed to improved cathode kinetics. Whereas, the use of lithium oxalate as an additive lead to the highest reversible capacity and lower irreversible losses.

  1. Nanoporous hybrid electrolytes

    KAUST Repository

    Schaefer, Jennifer L.

    2011-01-01

    Oligomer-suspended SiO2-polyethylene glycol nanoparticles are studied as porous media electrolytes. At SiO2 volume fractions, , bracketing a critical value y ≈ 0.29, the suspensions jam and their mechanical modulus increase by more than seven orders. For >y, the mean pore diameter is close to the anion size, yet the ionic conductivity remains surprisingly high and can be understood, at all , using a simple effective medium model proposed by Maxwell. SiO 2-polyethylene glycol hybrid electrolytes are also reported to manifest attractive electrochemical stability windows (0.3-6.3 V) and to reach a steady-state interfacial impedance when in contact with metallic lithium. © 2010 The Royal Society of Chemistry.

  2. A Long-Life Lithium Ion Battery with Enhanced Electrode/Electrolyte Interface by Using an Ionic Liquid Solution.

    Science.gov (United States)

    Elia, Giuseppe Antonio; Ulissi, Ulderico; Mueller, Franziska; Reiter, Jakub; Tsiouvaras, Nikolaos; Sun, Yang-Kook; Scrosati, Bruno; Passerini, Stefano; Hassoun, Jusef

    2016-05-10

    In this paper, we report an advanced long-life lithium ion battery, employing a Pyr14 TFSI-LiTFSI non-flammable ionic liquid (IL) electrolyte, a nanostructured tin carbon (Sn-C) nanocomposite anode, and a layered LiNi1/3 Co1/3 Mn1/3 O2 (NMC) cathode. The IL-based electrolyte is characterized in terms of conductivity and viscosity at various temperatures, revealing a Vogel-Tammann-Fulcher (VTF) trend. Lithium half-cells employing the Sn-C anode and NMC cathode in the Pyr14 TFSI-LiTFSI electrolyte are investigated by galvanostatic cycling at various temperatures, demonstrating the full compatibility of the electrolyte with the selected electrode materials. The NMC and Sn-C electrodes are combined into a cathode-limited full cell, which is subjected to prolonged cycling at 40 °C, revealing a very stable capacity of about 140 mAh g(-1) and retention above 99 % over 400 cycles. The electrode/electrolyte interface is further characterized through a combination of electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) investigations upon cell cycling. The remarkable performances reported here definitively indicate that IL-based lithium ion cells are suitable batteries for application in electric vehicles.

  3. Modelling electrolyte conductivity in a water electrolyzer cell

    DEFF Research Database (Denmark)

    Caspersen, Michael; Kirkegaard, Julius Bier

    2012-01-01

    An analytical model describing the hydrogen gas evolution under natural convection in an electrolyzer cell is developed. Main purpose of the model is to investigate the electrolyte conductivity through the cell under various conditions. Cell conductivity is calculated from a parallel resistor...... approximation depending on the gas phase distribution. The results are supported by applying a two-phase numerical model which shows good agreement with the analytical approach. The model can prove useful to optimize design factors of an electrolyzer cell for future use in that it provides clear tendencies...... for electrolyte conductivity from combinations of pressure, current density and electrolyte width among others....

  4. Modeling studies of electrolyte flow and bubble behavior in advanced Hall cells

    Science.gov (United States)

    Shekhar, R.; Evans, J. W.

    Much research was performed in recent years by corporations and university/government labs on materials for use in advanced Hall-Heroult cells. Attention has focussed on materials for use as wettable cathodes and inert anodes and much was achieved in terms of material development. Comparatively less attention was devoted to how these materials might be incorporated in new or existing cells, i.e., to how the cells should be designed and redesigned, to take full advantage of these materials. The effort, supported by the U.S. Department of Energy, to address this issue, is described. The primary objectives are cell design where electrolyte flow can be managed to promote both the removal of the anode gas bubbles and the convection of dissolved alumina in the inter-electrode region, under conditions where the anode-cathode distance is small. The principal experimental tool was a water model consisting of a large tank in which simulated anodes can be suspended in either the horizontal or vertical configurations. Gas generation was by forcing compressed air through porous graphite and the fine bubbles characteristic of inert anodes were produced by adding butanol to the water. Velocities were measured using a laser Doppler velocimeter. Velocity measurements with two different anode designs (one that is flat and the other that has grooves) are presented. The results show that the electrode configuration has a significant effect on the fluid flow pattern in the inter-electrode region. Furthermore, it is shown that rapid fluid flow is obtained when the cell is operated with a submerged anode.

  5. Electrochemical polymer electrolyte membranes

    CERN Document Server

    Fang, Jianhua; Wilkinson, David P

    2015-01-01

    Electrochemical Polymer Electrolyte Membranes covers PEMs from fundamentals to applications, describing their structure, properties, characterization, synthesis, and use in electrochemical energy storage and solar energy conversion technologies. Featuring chapters authored by leading experts from academia and industry, this authoritative text: Discusses cutting-edge methodologies in PEM material selection and fabricationPoints out important challenges in developing PEMs and recommends mitigation strategies to improve PEM performanceAnalyzes the cur

  6. Electrolyte Concentrates Treat Dehydration

    Science.gov (United States)

    2009-01-01

    Wellness Brands Inc. of Boulder, Colorado, exclusively licensed a unique electrolyte concentrate formula developed by Ames Research Center to treat and prevent dehydration in astronauts returning to Earth. Marketed as The Right Stuff, the company's NASA-derived formula is an ideal measure for athletes looking to combat dehydration and boost performance. Wellness Brands also plans to expand with products that make use of the formula's effective hydration properties to help treat conditions including heat stroke, altitude sickness, jet lag, and disease.

  7. Selection of Anodic Material Used in Electrolytic Process for Producing Hypophosphorous Acid

    Institute of Scientific and Technical Information of China (English)

    Fu Sheng WANG; Bing Kui SONG; Xiao Li HAN; Bao Gui ZHANG

    2004-01-01

    Black lead, Ti-Ru and Ti-PbO2 were used as anode and stainless steel was used as cathode.The electrolytic process of producing hypophosphorous acid with four-compartment electrodialytic cell was studied. The comparison of some factors, such as anodic voltage, product concentration and current efficiency, of black lead, Ti-Ru, and Ti-PbO2 electrodes was conducted. As a result, the Ti-PbO2 electrode is the optimal anode material used, it can be in electrolytic process for producing hypophosphorous acid.

  8. A Rechargeable Li-Air Fuel Cell Battery Based on Garnet Solid Electrolytes

    OpenAIRE

    Jiyang Sun; Ning Zhao; Yiqiu Li; Xiangxin Guo; Xuefei Feng; Xiaosong Liu; Zhi Liu; Guanglei Cui; Hao Zheng; Lin Gu; Hong Li

    2017-01-01

    Non-aqueous Li-air batteries have been intensively studied in the past few years for their theoretically super-high energy density. However, they cannot operate properly in real air because they contain highly unstable and volatile electrolytes. Here, we report the fabrication of solid-state Li-air batteries using garnet (i.e., Li6.4La3Zr1.4Ta0.6O12, LLZTO) ceramic disks with high density and ionic conductivity as the electrolytes and composite cathodes consisting of garnet powder, Li salts (...

  9. Effect of Methanol Crossover in a Liquid-FeedPolymer-Electrolyte Direct Methanol Fuel Cell

    OpenAIRE

    Ravikumar, MK; Shukla, AK

    1996-01-01

    The performance of a liquid-feed direct methanol fuel cell employing a proton-exchange membrane electrolyte with Pt-Ru/C as anode and Pt/C as cathode is reported. The fuel cell can deliver a power density of ca. 0.2 $W/cm^2$ at 95°C, sufficient to suggest that the stack construction is well worthwhile.Methanol crossover across the polymer electrolyte at concentrations beyond 2 M methanol affects the performance of the cell which appreciates with increasing operating temperature.

  10. Cathodic micro-arc electrodeposition of yttrium stabilized zirconia (YSZ) coatings on FeCrAl alloy

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The formation of ceramic coatings on metal substrate by cathodic electrolytic deposition (CELD) has received more attention in recent years. But only thin films can be prepared via CELD. Yttrium stabilized zirconia (YSZ) ceramic coatings were deposited on FeCrAl alloy by a novel technique--cathodic micro-arc electrodeposition (CMED). The result shows that, when a high pulse electric field is applied to the cathode which was pre-deposited with a thin YSZ film, dielectric breakdown occurs and micro-arc discharges appear. Coatings with reasonably thickness of ~300μm and crystalline structure can be deposited on the cathode by utilizing the energy of the micro-arc. The thickness of the as-deposited coating is dominated by the voltage and the frequency. Y2O3 is co-deposited with ZrO2 when Y(NO3)3 was added to the electrolyte, which stabilize t-phase, t′- phase and c-phase of ZrO2 at room temperature. The amount of the m-ZrO2 in the coating is diminished by increasing the concentration of Y(NO3)3 in the electrolyte. This report describes the processing of CMED and studies the microstructure of the deposited YSZ coatings.

  11. Development of membrane electrode assemblies for solid polymer fuel cells with higher performance, lower cost and carbon monoxide tolerance: improved cathode structures

    Energy Technology Data Exchange (ETDEWEB)

    Ralph, T.; Collis, N.; Edwards, N.

    1997-09-01

    Pre-commercial prototype solid polymer fuel cell (SPFC) modules and systems are presently available for sale. The widespread use of the technology has been limited, however, principally because of the high capital cost and insufficient power density. The UK Department of Trade and Industry`s Advanced Fuel Cells R and D Strategy has identified that the SPFC could, after appropriate development, be suitable for small scale combined heat and power and transportation applications in the UK. Key technology developments required to meet the cost and performance targets include increasing the power density of the membrane electrode assembly (MEA), reducing the platinum loading of the electrode materials and identifying anode catalysts with increased tolerance to reformate operation. The objectives of this project were to establish a SPFC single cell test facility at Johnson Matthey Technology Centre (JMTC) and evaluate the performance of a multicomponent cathode structure developed in a previous DTI supported project. The cathode combined two components in a multicomponent layer. This comprised an `ionomer` component consisting of a platinum catalyst which had been pre-impregnated with soluble polymer electrolyte, to enhance the platinum utilisation. This component was intimately mixed with a `gas transport` component, composed of a carbon/PTFE mixture, to provide gas transport channels. A Nafion surface coating to link together isolated pockets of `ionomer` component in the electrode depth completed the fabrication. (Author)

  12. Effects of compatibility of polymer binders with solvate ionic liquid electrolytes on discharge and charge reactions of lithium-sulfur batteries

    Science.gov (United States)

    Nakazawa, Toshitada; Ikoma, Ai; Kido, Ryosuke; Ueno, Kazuhide; Dokko, Kaoru; Watanabe, Masayoshi

    2016-03-01

    Electrochemical reactions in Li-S cells with a solvate ionic liquid (SIL) electrolyte composed of tetraglyme (G4) and Li[TFSA] (TFSA: bis(trifluoromethanesulfonyl)amide) are studied. The sulfur cathode (S cathode) comprises sulfur, carbon powder, and a polymer binder. Poly(ethylene oxide) (PEO) and poly(vinyl alcohol) (PVA-x) with different degrees of saponification (x%) are used as binders to prepare the composite cathodes. For the Li-S cell containing PEO binder, lithium polysulfides (Li2Sm, 2 ≤ m ≤ 8), reaction intermediates of the S cathode, dissolve into the electrolyte, and Li2Sm acts as a redox shuttle in the Li-S cell. In contrast, in the Li-S cell with PVA-x binder, the dissolution of Li2Sm is suppressed, leading to high columbic efficiencies during charge-discharge cycles. The compatibility of the PVA-x binder with the SIL electrolyte changes depending on the degree of saponification. Decreasing the degree of saponification leads to increased electrolyte uptake by the PVA-x binder, increasing the charge and discharge capacities of Li-S cell. The rate capability of Li-S cell is also enhanced by the partial swelling of the PVA-x binder. The enhanced performance of Li-S cell containing PVA-x is attributed to the lowering of resistance of Li+ ion transport in the composite cathode.

  13. Towards more thermally stable Li-ion battery electrolytes with salts and solvents sharing nitrile functionality

    Science.gov (United States)

    Kerner, Manfred; Lim, Du-Hyun; Jeschke, Steffen; Rydholm, Tomas; Ahn, Jou-Hyeon; Scheers, Johan

    2016-11-01

    The overall safety of Li-ion batteries is compromised by the state-of-the-art electrolytes; the thermally unstable lithium salt, lithium hexafluorophosphate (LiPF6), and flammable carbonate solvent mixtures. The problem is best addressed by new electrolyte compositions with thermally robust salts in low flammability solvents. In this work we introduce electrolytes with either of two lithium nitrile salts, lithium 4,5-dicyano-1,2,3-triazolate (LiDCTA) or lithium 4,5-dicyano-2-trifluoromethylimidazolide (LiTDI), in solvent mixtures with high flashpoint adiponitrile (ADN), as the main component. With sulfolane (SL) and ethylene carbonate (EC) as co-solvents the liquid temperature range of the electrolytes are extended to lower temperatures without lowering the flashpoint, but at the expense of high viscosities and moderate ionic conductivities. The anodic stabilities of the electrolytes are sufficient for LiFePO4 cathodes and can be charged/discharged for 20 cycles in Li/LiFePO4 cells with coulombic efficiencies exceeding 99% at best. The excellent thermal stabilities of the electrolytes with the solvent combination ADN:SL are promising for future electrochemical investigations at elevated temperatures (> 60 °C) to compensate the moderate transport properties and rate capability. The electrolytes with EC as a co-solvent, however, release CO2 by decomposition of EC in presence of a lithium salt, which potentially makes EC unsuitable for any application targeting higher operating temperatures.

  14. Reservoir Cathode for Electric Space Propulsion Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose a reservoir cathode to improve performance in both ion and Hall-effect thrusters. We propose to adapt our existing reservoir cathode technology to this...

  15. Reservoir Cathode for Electric Space Propulsion Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose a hollow reservoir cathode to improve performance in ion and Hall thrusters. We will adapt our existing reservoir cathode technology to this purpose....

  16. Computational Fluid Dynamics Modeling of a Lithium/Thionyl Chloride Battery with Electrolyte Flow

    Energy Technology Data Exchange (ETDEWEB)

    Gu, W.B.; Jungst, Rudolph G.; Nagasubramanian, Ganesan; Wang, C.Y.; Weidner, John.

    1999-06-11

    A two-dimensional model is developed to simulate discharge of a lithium/thionyl chloride primary battery. The model accounts for not only transport of species and charge, but also the electrode porosity variations and the electrolyte flow induced by the volume reduction caused by electrochemical reactions. Numerical simulations are performed using a finite volume method of computational fluid dynamics. The predicted discharge curves for various temperatures are compared to the experimental data with excellent agreement. Moreover, the simulation results. in conjunction with computer visualization and animation techniques, confirm that cell utilization in the temperature and current range of interest is limited by pore plugging or clogging of the front side of the cathode as a result of LiCl precipitation. The detailed two-dimensional flow simulation also shows that the electrolyte is replenished from the cell header predominantly through the separator into the front of the cathode during most parts of the discharge, especially for higher cell temperatures.

  17. Enhanced electrochemical performance of ammonium vanadium bronze through sodium cation intercalation and optimization of electrolyte.

    Science.gov (United States)

    Fei, Hailong; Liu, Xin; Li, Huan; Wei, Mingdeng

    2014-03-15

    A new type of platelet-like ammonium vanadium bronze (NH4)2V6O16 is first used as cathode material for Na-ion battery. The discharge capacity and cycling stability is improved by the intercalation of Na(+) and using NaPF6 as electrolyte. Raman spectrum shows that the crystalline structure of (NH4)2V6O16 is changed after the intercalation of Na(+) to (NH4)2V6O16. Furthermore, the obtained sodium ammonium vanadium bronze shows smaller charge transfer resistance than (NH4)2V6O16, which would favor superior discharge capacity and good cycling stability. Additionally, NaPF6 is prior to NaClO4 as electrolyte for ammonium vanadium bronze cathode materials.

  18. High-current-density, high brightness cathodes for free electron laser applications

    Energy Technology Data Exchange (ETDEWEB)

    Green, M.C. (Varian Associates, Palo Alto, CA (USA). Palo Alto Microwave Tube Div.)

    1987-06-01

    This report discusses the following topics: brightness and emittance of electron beams and cathodes; general requirements for cathodes in high brightness electron guns; candidate cathode types; plasma and field emission cathodes; true field emission cathodes; oxide cathodes; lanthanum hexaborides cathodes; laser driven thermionic cathodes; laser driven photocathodes; impregnated porous tungsten dispenser cathodes; and choice of best performing cathode types.

  19. Deposição eletrolítica catódica e anódica simultâneas para minimizar interferências de cobre e chumbo na determinação espectrofotométrica de cádmio em água e alimentos via reação com Verde de Malaquita e iodeto Cathodic and anodic simultaneous electrolytic deposition to minimize copper and lead interferences on spectrophotometric determination of cadmium by the Malachite Green-iodide reaction

    Directory of Open Access Journals (Sweden)

    Adriana Paiva de Oliveira

    2001-12-01

    Full Text Available Simultaneous electrolytic deposition is proposed for minimization of Cu2+ and Pb2+ interferences on automated determination of Cd2+ by the Malachite Green-iodide reaction. During electrolysis of sample in a cell with two Pt electrodes and a medium adjusted to 5% (v/v HNO3 + 0.1% (v/v H2SO4 + 0.5 mol L-1 NaCl, Cu2+ is deposited as Cu on the cathode, Pb2+ is deposited as PbO2 on the anode while Cd2+ is kept in solution. With 60 s electrolysis time and 0.25 A current, Pb2+ and Cu2+ levels up to 50 and 250 mg L-1 respectively, can be tolerated without interference. With on-line extraction of Cd2+ in anionic resin minicolumn, calibration graph in the 5.00 - 50.0 µg Cd L-1 range is obtained, corresponding to twenty measurements per hour, 0.7 mg Malachite Green and 500 mg KI and 5 mL sample consumed per determination. Results of the determination of Cd in certified reference materials, vegetables and tap water were in agreement with certified values and with those obtained by GFAAS at 95% confidence level. The detection limit is 0.23 µg Cd L-1 and the RSD for typical samples containing 13.0 µg Cd L-1 was 3.85 % (n= 12.

  20. Fabrication of TiO2 Cathodes by Anodic Oxidation for Hydrogen Generation from Electrolysis of Water

    Directory of Open Access Journals (Sweden)

    *İ. Koyuncu

    2014-09-01

    Full Text Available In this investigation, titanium oxide plates were used as cathode for hydrogen production in the aqueous solutions of sulfuric acid, potassium hydroxide, acetic acid and ammonia hydroxides electrolytes separately. Gaseous hydrogen was produced at the cathode and oxygen at the anode. For this purpose, titanium plates were fabricated in acid solution by anodic oxidation. Microstructure of TiO2 nanorod observation was conducted with scanning electron microscopy (SEM. The effects of operating conditions and the electrochemical test parameters, such as electrolytes concentration, temperature, and cell voltage were investigated. Also the performance of TiO2 cathode was compared to zirconium oxide and graphite electrodes. The results show that the highly rated, hydrogen production performance on TiO2 cathode has better than the other electrodes. The maximum rate of hydrogen production is by TiO2 cathode 8.18 ml/ (h. cm2. The cell efficiency for water electrolysis was reached 95% using titanium oxide electrode in 1.5 M H2SO4.

  1. Mechanistic Enhancement of SOFC Cathode Durability

    Energy Technology Data Exchange (ETDEWEB)

    Wachsman, Eric [Univ. of Maryland, College Park, MD (United States)

    2016-02-01

    Durability of solid oxide fuel cells (SOFC) under “real world” conditions is an issue for commercial deployment. In particular cathode exposure to moisture, CO2, Cr vapor (from interconnects and BOP), and particulates results in long-term performance degradation issues. Here, we have conducted a multi-faceted fundamental investigation of the effect of these contaminants on cathode performance degradation mechanisms in order to establish cathode composition/structures and operational conditions to enhance cathode durability.

  2. Electrolytic Recovery of Nickel from Spent Electroless Nickel Bath Solution

    Directory of Open Access Journals (Sweden)

    R. Idhayachander

    2010-01-01

    Full Text Available Plating industry is one of the largest polluting small scale industries and nickel plating is among the important surface finishing process in this industry. The waste generated during this operation contains toxic nickel. Nickel removal and recovery is of great interest from spent bath for environmental and economic reasons. Spent electroless nickel solution from a reed relay switch manufacturing industry situated in Chennai was taken for electrolytic recovery of nickel. Electrolytic experiment was carried out with mild steel and gold coated mild steel as cathode and the different parameters such as current density, time, mixing and pH of the solution were varied and recovery and current efficiency was studied. It was noticed that there was an increase in current efficiency up to 5 A/dm2 and after that it declines. There is no significant improvement with mixing but with modified cathode there was some improvement. Removal of nickel from the spent electroless nickel bath was 81.81% at 5 A/dm2 and pH 4.23. Under this condition, the content of nickel was reduced to 0.94 g/L from 5.16 g/L. with 62.97% current efficiency.

  3. Novel Cathodes Prepared by Impregnation Procedures

    Energy Technology Data Exchange (ETDEWEB)

    Eduardo Paz

    2006-09-30

    (1) We showed that similar results were obtained when using various LSM precursors to produce LSM-YSZ cathodes. (2) We showed that enhanced performance could be achieved by adding LSCo to LSMYSZ cathodes. (3) We have preliminary results showing that there is a slow deactivation with LSFYSZ cathodes.

  4. Electrochemical properties of La0.8Sr0.2FeO3-δbased composite cathode for intermediate temperature SOFC

    Institute of Scientific and Technical Information of China (English)

    ZHANG Naiqing; SUN Kening; JIA Dechang; ZHOU Derui

    2006-01-01

    La0.8Sr0.2FeO3-δ is a new kind of cathode material for intermediate SOFC, but its electrochemical activity is relative poor for the lanthanum gallate based solid oxide fuel cell. In this paper, a novel composite cathode of La0.8Sr0.2FeO3-δ/La0.9 Sr0.1Ga0.8Mg0.2O3-δ was prepared on the LSGM electrolyte substrate by screen-printing method. The results of cathodic polarization measurements show that the overpotential decreases significantly when the composite cathode is used instead of the La0.8Sr0.2FeO3-δ single layer cathode. The cathodic overpotential of the composite La0.8Sr0.2FeO3-δ/La0.9Sr0.1Ga0.8 Mg0.2O3-δ cathode is 150 mV at the current density of 0.2 A·m-2 at 800 ℃, while the cathodic overpotential of the La0.8 Sr0.2 FeO3-δ single layer cathode is higher thaN260 mV at the same condition. The electrochemical impedance spectroscopy was employed to investigate the polarization resistance of the cathode. The polarization resistance of the composite cathode is 1.20 Ω·m2 in open circuit condition, while the value of the single La0.8 Sr0.2 FeO3-δ cathode is 1.235 Ω·m2.

  5. Cathode catalysis performance of SmBaCuMO_(5+δ) (M=Fe, Co, Ni) in ammonia synthesis

    Institute of Scientific and Technical Information of China (English)

    张正方; 钟正平; 刘瑞泉

    2010-01-01

    The SmBaCuMO5+δ (M=Fe, Co, Ni) (SBCM) powders were synthesized by the citrate sol-gel method and the powders were sintered to ceramic pellets. The powders and sintered ceramic pellets were characterized with XRD, TEM and SEM measurements. The cathode catalytic performances of SBCM ceramic pellets for ammonia synthesis were studied from wet hydrogen and dry nitrogen at atmospheric pressure and low temperature, using SBCM ceramic pellets as cathode, Nafion proton exchange membrane as electrolyte, Ni-Ce0.8Sm0....

  6. A TEM study of morphological and structural degradation phenomena in LiFePO4-CB cathodes

    DEFF Research Database (Denmark)

    Ngo, Duc-The; Scipioni, Roberto; Simonsen, Søren Bredmose

    2016-01-01

    LiFePO4-based cathodes suffer from various degradation mechanisms, which influences the battery performance. In this paper, morphological and structural degradation phenomena in laboratory cathodes made of LiFePO4 mixed with carbon black (CB) in a 1 mol/L LiPF6 in EC : DMC (1:1 by weight......) electrolyte are investigated by transmission electron microscopy at various preparation, assembling, storage, and cycling stages. High-resolution transmission electron microscopy imaging shows that continuous SEI layers are formed on the LiFePO4 particles and that both storage and cycling affect the formation...

  7. High-performance solid oxide fuel cells based on a thin La0.8Sr0.2Ga0.8Mg0.2O3-δ electrolyte membrane supported by a nickel-based anode of unique architecture

    Science.gov (United States)

    Sun, Haibin; Chen, Yu; Chen, Fanglin; Zhang, Yujun; Liu, Meilin

    2016-01-01

    Solid oxide fuel cells (SOFCs) based on a thin La0.8Sr0.2Ga0.8Mg0.2O3-δ (LSGM) electrolyte membrane supported by a nickel-based anode often suffers from undesirable reaction/diffusion between the Ni anode and the LSGM during high-temperature co-firing. In this study, a high performance intermediate-temperature SOFC is fabricated by depositing thin LSGM electrolyte membranes on a LSGM backbone of unique architecture coated with nano-sized Ni and Gd0.1Ce0.9O2-δ (GDC) particles via a combination of freeze-drying tape-casting, slurry drop-coating, and solution infiltration. The thickness of the dense LSGM electrolyte membranes is ∼30 μm while the undesirable reaction/diffusion between Ni and LSGM are effectively hindered because of the relatively low firing temperature, as confirmed by XRD analysis. Single cells show peak power densities of 1.61 W cm-2 at 700 °C and 0.52 W cm-2 at 600 °C using 3 vol% humidified H2 as fuel and ambient air as oxidant. The cell performance is very stable for 115 h at a constant current density of 0.303 A cm-2 at 600 °C.

  8. 尿素作为造孔剂对聚乙烯支撑的PAMS聚合物电解质性能的改进%Performance Improvement of Polyethylene-Supported PAMS Electrolyte Using Urea as Foaming Agent

    Institute of Scientific and Technical Information of China (English)

    陈朗; 饶睦敏; 李伟善; 许梦清; 廖友好; 谭春林; 易金

    2011-01-01

    采用乳液聚合法合成聚(丙烯腈-甲基丙烯酸甲酯-苯乙烯)(P(AN-MMA-ST)或者共聚物PAMS),并利用尿素作为造孔剂制备了聚乙烯(PE)支撑的PAMS聚合物膜(PE-PAMS-U)及凝胶聚合物电解质(GPE).利用傅里叶变换红外(FTIR)光谱、X射线衍射(XRD)、扫描电子显微镜(SEM)、热重(TG)分析、线性电位扫描(LSV)、电化学阻抗谱(EIS)以及充放电等方法对PAMS聚合物以及PE支撑的聚(丙烯腈-甲基丙烯酸甲酯-苯乙烯)(PE-PAMS)聚合物隔膜及凝胶聚合物电解质的性能进行了研究.结果表明,利用尿素作为造孔剂可以提高PE-PAMS凝胶聚合物的性能.由于尿素的加入,聚合物膜呈现均匀的微孔结构,室温下的电导率从1.1×10-3S·cm-1提高到2.15x10-3 S·cm-1.同时,锂电极/聚合物电解质界面上的电荷传递电阻也从480 Ω·cm2降低到250 Ω·cm2.电化学稳定窗口为5.0 V.电池(Li/PE支撑的GPE/LiCoO2)的测试证明,用尿素作为造孔剂的凝胶聚合物锂离子电池表现出优良的倍率性能和循环性能.%Poly(acrylonitrile-methyl methacrylate-styrene) (PAMS) was synthesized by emulsion polymerization and a polyethylene (PE)-supported membrane was prepared using urea as foaming agent (PE-PAMS-U). The structure and performance of the PAMS copolymer, PE-PAMS-U membrane and corresponding gel polymer electrolyte (GPE) were characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetry (TG), linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS) and by a charge/discharge test.We found that the performance of the PE-PAMS-U based GPE could be improved when using urea as a foaming agent. With the use of urea the pore size of the membrane becomes uniform, the ionic conductivity of the GPE improves from 1.1×10-3 to 2.15×10-3 S·cm-1 at room temperature and the interfacial resistance between the GPE and lithium is reduced from 480

  9. Magnetron sputtered gadolinia-doped ceria diffusion barriers for metal-supported solid oxide fuel cells

    DEFF Research Database (Denmark)

    Sønderby, Steffen; Klemensø, Trine; Christensen, Bjarke H.;

    2014-01-01

    and substrate bias voltage. A GDC layer thickness of 0.6 μm is found to effectively block Sr diffusion when bias voltage and deposition temperature is tuned to promote dense coatings. The adatom mobility has a large influence on the film density. Low temperature and bias voltage result in underdense column......Gadolinia-doped ceria (GDC) thin films are deposited by reactive magnetron sputtering in an industrial-scale setup and implemented as barrier layers between the cathode and electrolyte in metal-based solid oxide fuel cells consisting of a metal support, an electrolyte of ZrO2 co-doped with Sc2O3...... and Y2O3 (ScYSZ) and a Sr-doped lanthanum cobalt oxide cathode. In order to optimize the deposition of GDC to obtain high electrochemical performance of the cells, the influence of film thickness and adatom mobility is studied. The adatom mobility is varied by tuning the deposition temperature...

  10. Microhollow Cathode Discharge Excimer Lamps

    Science.gov (United States)

    Schoenbach, K. H.

    1999-11-01

    character. Reducing the diameter of the cathode hole in a hollow cathode discharge geometry to values on the order of 100 μm has allowed us to extend the pressure range of stable, direct current hollow cathode gas discharges up to atmospheric pressure. The large concentration of high-energy electrons generated in the cathode fall, in combination with the high neutral gas density favors three-body processes such as excimer formation. Excimer emission in xenon discharges peaking at 172 nm, was observed with efficiencies between 6% and 9% at pressures of several hundred Torr. Typical forward voltages are 200 V at dc currents up to 8 mA. Pulsed operation allowed us to extend the current range to 80 mA with corresponding linear increase in optical power. Spatially resolved measurements showed that the source of the excimer radiation at atmospheric pressure and currents of less than 8 mA is confined to the cathode opening. The radiative emittance at 8 mA and atmospheric pressure is approximately 20 W/cm^2. With reduced pressure and increased current, respectively, the excimer source extends into the area outside the cathode hole. Besides in xenon, excimer emission in argon at a peak wavelength of 128 nm has been recorded. In addition to operating the discharge in rare gases, we have also explored its use as rare gas-halide excimer source. In a gas mixture containing 1% ArF we were able to generate stable dc discharges in flowing gas at pressures ranging from 100 Torr to atmospheric pressure. The spectra of the high-pressure ArF discharges are dominated by excimer radiation peaking at 193 nm. The excimer emission of a single ArF discharge at 700 Torr was measured as 150 mW at an efficiency of 3%. Parallel operation of these discharges by means of a resistive anode, which has recently been demonstrated for argon discharges, offers the possibility to use microhollow cathode discharge arrays as dc-excimer lamps, with estimated power densities exceeding 10 W/cm^2. abstract

  11. Evaluation of wear rates and mechanisms of titanium diboride-graphite composite materials proposed for use as cathodes in Hall-Heroult cells

    Energy Technology Data Exchange (ETDEWEB)

    Pool, K.H.; Brimhall, J.L.; Raney, P.J.; Hart, P.E.

    1987-01-01

    Purpose of this study was to measure the initial wear rates of TiB/sub 2/ carbon-containing cathode materials (TiB/sub 2/-G) under electrolytic conditions. Parameters evaluated included bath ratio, current density, and aluminum pad thickness. In order to measure initial wear rates, the tests were limited to 8 h.

  12. Promising Cell Configuration for Next-Generation Energy Storage: Li2S/Graphite Battery Enabled by a Solvate Ionic Liquid Electrolyte.

    Science.gov (United States)

    Li, Zhe; Zhang, Shiguo; Terada, Shoshi; Ma, Xiaofeng; Ikeda, Kohei; Kamei, Yutaro; Zhang, Ce; Dokko, Kaoru; Watanabe, Masayoshi

    2016-06-29

    Lithium-ion sulfur batteries with a [graphite|solvate ionic liquid electrolyte|lithium sulfide (Li2S)] structure are developed to realize high performance batteries without the issue of lithium anode. Li2S has recently emerged as a promising cathode material, due to its high theoretical specific capacity of 1166 mAh/g and its great potential in the development of lithium-ion sulfur batteries with a lithium-free anode such as graphite. Unfortunately, the electrochemical Li(+) intercalation/deintercalation in graphite is highly electrolyte-selective: whereas the process works well in the carbonate electrolytes inherited from Li-ion batteries, it cannot take place in the ether electrolytes commonly used for Li-S batteries, because the cointercalation of the solvent destroys the crystalline structure of graphite. Thus, only very few studies have focused on graphite-based Li-S full cells. In this work, simple graphite-based Li-S full cells were fabricated employing electrolytes beyond the conventional carbonates, in combination with highly loaded Li2S/graphene composite cathodes (Li2S loading: 2.2 mg/cm(2)). In particular, solvate ionic liquids can act as a single-phase electrolyte simultaneously compatible with both the Li2S cathode and the graphite anode and can further improve the battery performance by suppressing the shuttle effect. Consequently, these lithium-ion sulfur batteries show a stable and reversible charge-discharge behavior, along with a very high Coulombic efficiency.

  13. Final Technical Report Microwave Assisted Electrolyte Cell for Primary Aluminum Production

    Energy Technology Data Exchange (ETDEWEB)

    Xiaodi Huang; J.Y. Hwang

    2007-04-18

    This research addresses the high priority research need for developing inert anode and wetted cathode technology, as defined in the Aluminum Industry Technology Roadmap and Inert Anode Roadmap, with the performance targets: a) significantly reducing the energy intensity of aluminum production, b) ultimately eliminating anode-related CO2 emissions, and c) reducing aluminum production costs. This research intended to develop a new electrometallurgical extraction technology by introducing microwave irradiation into the current electrolytic cells for primary aluminum production. This technology aimed at accelerating the alumina electrolysis reduction rate and lowering the aluminum production temperature, coupled with the uses of nickel based superalloy inert anode, nickel based superalloy wetted cathode, and modified salt electrolyte. Michigan Technological University, collaborating with Cober Electronic and Century Aluminum, conducted bench-scale research for evaluation of this technology. This research included three sub-topics: a) fluoride microwave absorption; b) microwave assisted electrolytic cell design and fabrication; and c) aluminum electrowinning tests using the microwave assisted electrolytic cell. This research concludes that the typically used fluoride compound for aluminum electrowinning is not a good microwave absorbing material at room temperature. However, it becomes an excellent microwave absorbing material above 550°C. The electrowinning tests did not show benefit to introduce microwave irradiation into the electrolytic cell. The experiments revealed that the nickel-based superalloy is not suitable for use as a cathode material; although it wets with molten aluminum, it causes severe reaction with molten aluminum. In the anode experiments, the chosen superalloy did not meet corrosion resistance requirements. A nicked based alloy without iron content could be further investigated.

  14. Fabrication of All-Solid-State Lithium-ion Cells using Three-Dimensionally Structured Solid Electrolyte Li7La3Zr2O12 Pellets

    Directory of Open Access Journals (Sweden)

    MAO SHOJI

    2016-08-01

    Full Text Available All-solid-state lithium-ion batteries using Li+-ion conducting ceramic electrolytes have been focused on as attractive future batteries for electric vehicles and renewable energy conversion systems because high safety can be realized due to non-flammability of ceramic electrolytes. In addition, a higher volumetric energy density than that of current lithium-ion batteries is expected since the all-solid-state lithium-ion batteries can be made in bipolar cell configurations. However, the special ideas and techniques based on ceramic processing are required to construct the electrochemical interface for all-solid-state lithium-ion batteries since the battery development has been done so far based on liquid electrolyte system over 100 years. As one of promising approaches to develop practical all-solid-state batteries, we have been focusing on three-dimensionally (3D structured cell configurations such as an interdigitated combination of 3D pillars of cathode and anode, which can be realized by using solid electrolyte membranes with hole-array structures. The application of such kinds of 3D structures effectively increases the interface between solid electrode and solid electrolyte per unit volume, lowering the internal resistance of all-solid-state lithium-ion batteries. In this study, Li6.25Al0.25La3Zr2O12 (LLZAl, which is a Al-doped Li7La3Zr2O12 (LLZ with Li+-ion conductivity of ~10–4 S cm–1 at room temperature and high stability against lithium-metal, was used as a solid electrolyte, and its pellets with 700 um depth holes in 700 x 700 um2 area were fabricated to construct 3D-structured all-solid-state batteries with LiCoO2 / LLZAl / lithium-metal configuration. It is expected that the LiCoO2-LLZAl interface is formed by point to point contact even when the LLZAl pellet with 3D hole-array structure is applied. Therefore, the application of mechanically soft Li3BO3 with a low melting point at around 700 °C was also performed as a supporting

  15. One-step electrodeposition process to fabricate cathodic superhydrophobic surface

    Science.gov (United States)

    Chen, Zhi; Li, Feng; Hao, Limei; Chen, Anqi; Kong, Youchao

    2011-12-01

    In this work, a rapid one-step process is developed to fabricate superhydrophobic cathodic surface by electrodepositing copper plate in an electrolyte solution containing manganese chloride (MnCl2·4H2O), myristic acid (CH3(CH2)12COOH) and ethanol. The superhydrophobic surfaces were characterized by means of scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The shortest electrolysis time for fabricating a superhydrophobic surface is about 1 min, the measured maximum contact angle is 163° and rolling angle is less than 3°. Furthermore, this method can be easily extended to other conductive materials. The approach is time-saving and cheap, and it is supposed to have a promising future in industrial fields.

  16. One-step electrodeposition process to fabricate cathodic superhydrophobic surface

    Energy Technology Data Exchange (ETDEWEB)

    Chen Zhi, E-mail: c2002z@nwpu.edu.cn [Department of Applied Physics, Northwestern Polytechnical University, Xi' an 710129 (China); Li Feng [Department of Applied Physics, Northwestern Polytechnical University, Xi' an 710129 (China); Hao Limei [Department of Applied Physics, Xi' an University of Science and Technology, Xi' an 710054 (China); Chen Anqi; Kong Youchao [Department of Applied Physics, Northwestern Polytechnical University, Xi' an 710129 (China)

    2011-12-01

    In this work, a rapid one-step process is developed to fabricate superhydrophobic cathodic surface by electrodepositing copper plate in an electrolyte solution containing manganese chloride (MnCl{sub 2}{center_dot}4H{sub 2}O), myristic acid (CH{sub 3}(CH{sub 2}){sub 12}COOH) and ethanol. The superhydrophobic surfaces were characterized by means of scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The shortest electrolysis time for fabricating a superhydrophobic surface is about 1 min, the measured maximum contact angle is 163 Degree-Sign and rolling angle is less than 3 Degree-Sign . Furthermore, this method can be easily extended to other conductive materials. The approach is time-saving and cheap, and it is supposed to have a promising future in industrial fields.

  17. Novel Ceramic Materials for Polymer Electrolyte Membrane Water Electrolysers' Anodes

    DEFF Research Database (Denmark)

    Polonsky, J.; Bouzek, K.; Prag, Carsten Brorson

    2012-01-01

    Tantalum carbide was evaluated as a possible new support for the IrO2 for use in anodes of polymer electrolyte membrane water electrolysers. A series of supported electrocatalysts varying in mass content of iridium oxide was prepared. XRD, powder conductivity measurements and cyclic and linear sw...

  18. Effect of ethylene glycol bis (propionitrile) ether (EGBE) on the performance and interfacial chemistry of lithium-rich layered oxide cathode

    Science.gov (United States)

    Hong, Pengbo; Xu, Mengqing; Zheng, Xiongwen; Zhu, Yunmin; Liao, Youhao; Xing, Lidan; Huang, Qiming; Wan, Huaping; Yang, Yongjun; Li, Weishan

    2016-10-01

    Ethylene glycol bis (propionitrile) ether (EGBE) is used as an electrolyte additive to improve the cycling stability and rate capability of Li/Li1.2Mn0.54Ni0.13Co0.13O2 cells at high operating voltage (4.8 V). After 150 cycles, cells with 1.0 wt% of EGBE containing electrolyte have remarkable cycling performance, 89.0% capacity retention; while the cells with baseline electrolyte only remain 67.4% capacity retention. Linear sweep voltammetry (LSV) and computation results demonstrate that EGBE preferably oxidizes on the cathode surface compared to the LiPF6/carbonate electrolyte. In order to further understand the effects of EGBE on Li1.2Mn0.54Ni0.13Co0.13O2 cathode upon cycling at high voltage, electrochemical behaviors and ex-situ surface analysis of Li1.2Mn0.54Ni0.13Co0.13O2 are investigated via electrochemical impedance spectroscopy (EIS), scanning electron spectroscopy (SEM), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and inductive coupled plasma spectroscopy (ICP-MS). The improved cycling performance can be attributed to more stable and robust surface layer yield via incorporation of EGBE, which mitigates the oxidation of electrolyte on the cathode electrode, and also inhibits the dissolution of bulk transition metal ions as well upon cycling at high voltage.

  19. Analysis of the process main variables influence in the rejection of the cathodes during copper electrorefining; Analisis de las principales variables de proceso que influyen en el rechazo de los catodos durante el electrorrefino del cobre

    Energy Technology Data Exchange (ETDEWEB)

    Cifuentes, G.; Vargas, C.; Simpson, J.

    2009-07-01

    An experimental circuit of copper electrorefining using three types of anodes coming from three different Chilean foundries: Hernan Videla Lira, Las Ventanas and El Teniente was used to simulate the electrorefining process. In this circuit the problem of the cathode rejection and the influence of some process variables in this phenomenon were studied. The variables analyzed were: electrolyte cell flow, solids in suspension, current density, lead doping in the anodes and density and particle size of the anodic slimes generated. The main results obtained from the experimental circuit were the following: the electrolyte flow doesn't affect significantly the cathodic rejection, an increase of current density produces a decrease of cathodic rejections, the presence of the solids in suspension causes cathodes outside of norm, and to bigger quantity of lead in the anodes smallest were the rejections. (Author) 20 refs.

  20. Alternative Anodes for the Electrolytic Reduction of Uranium Dioxide

    Science.gov (United States)

    Merwin, Augustus

    Reprocessing of spent nuclear fuel is an essential step in closing the nuclear fuel cycle. In order to consume current stockpiles, ceramic uranium dioxide spent nuclear fuel will be subjected to an electrolytic reduction process. The current reduction process employs a platinum anode and a stainless steel alloy 316 cathode in a molten salt bath consisting of LiCl-2wt% Li 2O and occurs at 700°C. A major shortcoming of the existing process is the degradation of the platinum anode under the severely oxidizing conditions encountered during electrolytic reduction. This work investigates alternative anode materials for the electrolytic reduction of uranium oxide. The high temperature and extreme oxidizing conditions encountered in these studies necessitated a unique set of design constraints on the system. Thus, a customized experimental apparatus was designed and constructed. The electrochemical experiments were performed in an electrochemical reactor placed inside a furnace. This entire setup was housed inside a glove box, in order to maintain an inert atmosphere. This study investigates alternative anode materials through accelerated corrosion testing. Surface morphology was studied using scanning electron microscopy. Surface chemistry was characterized using energy dispersive spectroscopy and Raman spectroscopy. Electrochemical behavior of candidate materials was evaluated using potentiodynamic polarization characteristics. After narrowing the number of candidate electrode materials, ferrous stainless steel alloy 316, nickel based Inconel 718 and elemental tungsten were chosen for further investigation. Of these materials only tungsten was found to be sufficiently stable at the anodic potential required for electrolysis of uranium dioxide in molten salt. The tungsten anode and stainless steel alloy 316 cathode electrode system was studied at the required reduction potential for UO2 with varying lithium oxide concentrations. Electrochemical impedance spectroscopy