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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. 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.

  4. Effects of carbon supports on Pt distribution, ionomer coverage and cathode performance for polymer electrolyte fuel cells

    Science.gov (United States)

    Park, Young-Chul; Tokiwa, Haruki; Kakinuma, Katsuyoshi; Watanabe, Masahiro; Uchida, Makoto

    2016-05-01

    We investigate the effects of the carbon supports on the Pt distribution, ionomer coverage and cathode performance of carbon-supported Pt catalysts, by using STEM observation, N2 adsorption analysis and electrochemical characterization. According to the STEM observation, the effective Pt surface area (S(e)Pt), which is determined by the location and size of the Pt particles on the supports, increases in the following order: c-Pt/CB cell performance in the high current density region. In spite of the highest Pt utilization (UPt) value (>90%) and uniform ionomer coverage, the c-Pt/CB catalyst shows the lowest cell performance due to the lower S(e)Pt value. On the other hand, the n-Pt/AB250 catalyst, for which all of the Pt particles exist only on the exterior surface, is found to be the most attractive in order to generate the large current densities required by actual fuel cell operation.

  5. 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.

  6. 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.

  7. 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.

  8. Intermetallics as cathode materials in the electrolytic hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Stojic, D.L.; Maksic, A.D.; Kaninski, M.P.M. [Vinca Inst. of Nuclear Sciences, Belgrade (Serbia and Montenegro). Lab. of Physical Chemistry; Cekic, B.D. [Vinca Inst. of Nuclear Sciences, Belgrade (Serbia and Montenegro). Lab. of Physics; Miljanic, S.S. [Belgrade Univ. (Serbia and Montenegro). Faculty of Physical Chemistry

    2005-01-01

    The intermetallics of transition metals have been investigated as cathode materials for the production of hydrogen by electrolysis from water-KOH solutions, in an attempt to increase the electrolytic process efficiency. We found that the best effect among all investigated cathodes (Hf{sub 2}Fe, Zr-Pt, Nb-Pd(I), Pd-Ta, Nb-Pd(II), Ti-Pt) exhibits the Hf{sub 2}Fe phase. These materials were compared with conventional cathodes (Fe and Ni), often used in the alkaline electrolysis. A significant upgrade of the electrolytic efficiency using intermetallics, either in pure KOH electrolyte or in combination with ionic activators added in situ, was achieved. The effects of these cathode materials on the process efficiency were discussed in the context of transition metal features that issue from their electronic configuration. (Author)

  9. 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...

  10. Modelling cathode catalyst degradation in polymer electrolyte fuel cells

    OpenAIRE

    Rinaldo, Steven Giordano

    2013-01-01

    Nano-sized Pt particles in the cathode catalyst layer of a polymer electrolyte fuel cell afford a high initial electrochemically active surface-area. However, the gain in active surface area for desired surface reactions is offset in part by enhanced rates of degradation processes that cause losses in catalyst mass, catalyst surface-area, and electrocatalytic activity. The loss of electrochemically active surface-area of the catalyst causes severe performance degradation over relevant lifetim...

  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

    The degradation of anode-supported cells was studied over 1500 h as a function of cell polarization either in air or oxygen on the cathode side. Based on impedance analysis, contributions of the anode and cathode to the increase of total resistance were assigned. Accordingly, the degradation rate......-stabilized zirconia electrolyte and consequently a reduced three-phase boundary length. (C) 2008 The Electrochemical Society....

  12. Microstructure and characterization of a novel cobalt coating prepared by cathode plasma electrolytic deposition

    Science.gov (United States)

    Quan, Cheng; He, Yedong

    2015-10-01

    A novel cobalt coating was prepared by cathode plasma electrolytic deposition (CPED). The kinetics of the electrode process in cathode plasma electrolytic deposition was studied. The composition and microstructure of the deposited coatings were investigated by SEM, EDS, XRD and TEM. The novel cobalt coatings were dense and uniform, showing a typically molten morphology, and were deposited with a rather fast rate. Different from the coatings prepared by conventional electrodeposition or chemical plating, pure cobalt coatings with face center cubic (fcc) structure were obtained by CPED. The deposited coatings were nanocrystalline structure with an average grain size of 40-50 nm, exhibited high hardness, excellent adhesion with the stainless steels, and superior wear resistance. The properties of the novel cobalt coatings prepared by CPED have been improved significantly, as compared with that prepared by conventional methods. It reveals that cathode plasma electrolytic deposition is an effective way to prepare novel cobalt coatings with high quality.

  13. 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

  14. 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.

  15. 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...

  16. Chemical compatibility study of melilite-type gallate solid electrolyte with different cathode materials

    Science.gov (United States)

    Mancini, Alessandro; Felice, Valeria; Natali Sora, Isabella; Malavasi, Lorenzo; Tealdi, Cristina

    2014-05-01

    Chemical reactivity between cathodes and electrolytes is a crucial issue for long term SOFCs stability and performances. In this study, chemical reactivity between selected cathodic materials and the ionic conducting melilite La1.50Sr0.50Ga3O7.25 has been extensively investigated by X-ray powder diffraction in a wide temperature range (up to 1573 K). Perovskite-type La0.8Sr0.2MnO3-d and La0.8Sr0.2Fe0.8Cu0.2O3-d and K2NiF4-type La2NiO4+d were selected as cathode materials. The results of this study allow identifying the most suitable electrode material to be used in combination with the melilite-type gallate electrolyte and set the basis for future work on this novel system.

  17. Characterization of the Cathode Electrolyte Interface in Lithium Ion Batteries by Desorption Electrospray Ionization Mass Spectrometry.

    Science.gov (United States)

    Liu, Yao-Min; G Nicolau, Bruno; Esbenshade, Jennifer L; Gewirth, Andrew A

    2016-07-19

    The solid electrolyte interface (SEI) formed via electrolyte decomposition on the anode of lithium ion batteries is largely responsible for the stable cycling of conventional lithium ion batteries. Similarly, there is a lesser-known analogous layer on the cathode side of a lithium ion battery, termed the cathode electrolyte interface (CEI), whose composition and role are debated. To confirm the existence and composition of the CEI, desorption electrospray ionization mass spectrometry (DESI-MS) is applied to study common lithium ion battery cathodes. We observe CEI formation on the LiMn2O4 cathode material after cycling between 3.5 and 4.5 V vs Li/Li(+) in electrolyte solution containing 1 M LiPF6 or LiClO4 in 1:1 (v/v) ethylene carbonate (EC) and dimethyl carbonate (DMC). Intact poly(ethylene glycol) dimethyl ether is identified as the electrolyte degradation product on the cathode surface by the high mass-resolution Orbitrap mass spectrometer. When EC is paired with ethyl methyl carbonate (EMC), poly(ethylene glycol) dimethyl ether, poly(ethylene glycol) ethyl methyl ether, and poly(ethylene glycol) are found on the surface simultaneously. The presence of ethoxy and methoxy end groups indicates both methoxide and ethoxide are produced and involved in the process of oligomerization. Au surfaces cycled under different electrochemical windows as model systems for Li-ion battery anodes are also examined. Interestingly, the identical oligomeric species to those found in the CEI are found on Au surfaces after running five cycles between 2.0 and 0.1 V vs Li/Li(+) in half-cells. These results show that DESI-MS provides intact molecular information on battery electrodes, enabling deeper understanding of the SEI or CEI composition. PMID:27346184

  18. Synthesis, processing and characterization of the solid oxide half-cells cathode/electrolyte of strontium-doped lanthanum manganite/Yttria-stabilized zirconia

    International Nuclear Information System (INIS)

    The ceramic films of strontium-doped lanthanum manganite (LSM) and strontium doped lanthanum manganite/Yttria-stabilized zirconia (LSM/YSZ) are used as cathodes of the high temperature solid oxide fuel cells (HTSOFC). These porous ceramic films had been deposited on the YSZ dense ceramic substrate, used as electrolyte, structural component of the module, thus conferring a configuration of half-cell called auto-support. The study of the half-cell it is basic, therefore in the interface cathode/electrolyte occurs the oxygen reduction reaction, consequently influencing in the performance of the HTSOFC. In this direction, the present work contributes for the processing of thin films, using the wet powder spraying technique, adopted for the conformation of the ceramic films for allowing the attainment of porous layers with thicknesses varied in the order of micrometers. The LSM powders were synthesized by the citrate technique and the LSM/YSZ powders synthesized by the solid mixture technique. In the stage of formation were prepared organic suspensions of LSM and LSM/YSZ fed by gravity in a manual aerograph. For the formation of the YSZ substrate was used a hydraulic uniaxial press. The attainment of solid oxide half-cells cathode/electrolyte was possible of crystalline structures hexagonal for phase LSM and cubic for phase YSZ. The half-cells micrographs show that the YSZ substrate is dense, enough to be used as solid electrolyte, and the LSM and LSM/YSZ films are presented porous with approximately 30 μm of thickness and good adherence between the cathodes and the electrolyte. The presence of composite cathode between the LSM cathode and YSZ substrate, presented an increase in the electrochemical performance in the oxygen reduction reaction. (author)

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

    DEFF Research Database (Denmark)

    Knibbe, Ruth; Hjelm, Johan; Menon, Mohan;

    2010-01-01

    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....

  20. 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)

  1. 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].

  2. Compatibility of lithium difluoro(sulfato)borate-based electrolyte for LiMn2O4 cathode

    Science.gov (United States)

    Li, Shiyou; Liu, Jinliang; Li, Lingxia; Li, Xiaopeng; Jing, Jie; Cui, Xiaoling

    2015-03-01

    Lithium difluoro(sulfato)borate (LiBF2SO4) is investigated as a lithium salt for non-aqueous electrolytes for LiMn2O4 cathode in lithium-ion batteries. Inductively coupled plasma-atomic emission spectrometry analysis is used to analyze the Mn dissolution. Scanning electron microscopy and AC impedance measurements analysis are used to analyze the formation of the surface film on the surface of LiMn2O4 cathode. These results demonstrate that LiBF2SO4-based electrolyte favourably facilitates the formation of an effective and conductive interface film on the cathode surface to improve the stabilization of cathode/electrolyte interface. Besides, LiMn2O4 cells using LiBF2SO4-based electrolyte exerts several advantages, such as stable cycling performance, low cell impedance, low polarization resistance, and good rate performance. It suggests that LiBF2SO4-based electrolyte has good compatibility with LiMn2O4 cathode, and LiBF2SO4 would be a very promising lithium salt for LiMn2O4 cathode in lithium-ion batteries.

  3. Preparation of Pt deposited nanotubular TiO2 as cathodes for enhanced photoelectrochemical hydrogen production using seawater electrolytes

    International Nuclear Information System (INIS)

    The purpose of this study was to develop effective cathodes to increase the production of hydrogen and use the seawater, an abundant resource in the earth as the electrolyte in photoelectrochemical systems. In order to fabricate the Pt/TiO2 cathodes, various contents of the Pt precursor (0-0.4 wt%) deposited by the electrodeposition method were used. On the basis of the hydrogen evolution rate, 0.2 wt% Pt/TiO2 was observed to exhibit the best performance among the various Pt/TiO2 cathodes with the natural seawater and two concentrated seawater electrolytes obtained from single (nanofiltration) and combined membrane (nanofiltration and reverse osmosis) processes. The surface characterizations exhibited that crystal structures and morphological properties of Pt and TiO2 found the results of XRD pattern and SEM/TEM images, respectively. - Graphical abstract: On the basis of photoelectrochemical hydrogen production, 0.2 wt% Pt/TiO2 was observed to exhibit the best performance among the various Pt/TIO2 cathodes with natural seawater. In comparison of hydrogen evolution rate with various seawater electrolytes, 0.2 wt% Pt/TiO2 was found to show the better performance as cathode with the concentrated seawater electrolytes obtained from membrane. Highlights: → Pt deposited TiO2 electrodes are used as cathode in PEC H2 production. → Natural and concentrated seawater by membranes are used as electrolytes in PEC. → Pt/TiO2 shows a good performance as cathode with seawater electrolytes. → H2 evolution rate increases with more concentrated seawater electrolyte. → Highly saline seawater is useful resource for H2 production.

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

    DEFF Research Database (Denmark)

    Gil, Vanesa; Kammer Hansen, Kent

    2014-01-01

    -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...... with infiltrated LSM nanoparticles is shown in Fig. 1. Figure 1. Cross section of LSM infiltrated cathode supported cell. [Formula]...

  5. Chemical compatibility study of melilite-type gallate solid electrolyte with different cathode materials

    Energy Technology Data Exchange (ETDEWEB)

    Mancini, Alessandro [INSTM R.U. and Department of Chemistry–Physical Chemistry Division, University of Pavia, Pavia I-27100 (Italy); Felice, Valeria; Natali Sora, Isabella [INSTM R.U. and Department of Engineering, University of Bergamo, Dalmine, Bergamo I-24044 (Italy); Malavasi, Lorenzo [INSTM R.U. and Department of Chemistry–Physical Chemistry Division, University of Pavia, Pavia I-27100 (Italy); Tealdi, Cristina, E-mail: cristina.tealdi@unipv.it [INSTM R.U. and Department of Chemistry–Physical Chemistry Division, University of Pavia, Pavia I-27100 (Italy)

    2014-05-01

    Chemical reactivity between cathodes and electrolytes is a crucial issue for long term SOFCs stability and performances. In this study, chemical reactivity between selected cathodic materials and the ionic conducting melilite La{sub 1.50}Sr{sub 0.50}Ga{sub 3}O{sub 7.25} has been extensively investigated by X-ray powder diffraction in a wide temperature range (up to 1573 K). Perovskite-type La{sub 0.8}Sr{sub 0.2}MnO{sub 3−d} and La{sub 0.8}Sr{sub 0.2}Fe{sub 0.8}Cu{sub 0.2}O{sub 3−d} and K{sub 2}NiF{sub 4}-type La{sub 2}NiO{sub 4+d} were selected as cathode materials. The results of this study allow identifying the most suitable electrode material to be used in combination with the melilite-type gallate electrolyte and set the basis for future work on this novel system. - Graphical abstract: Chemical reactivity between cathodes and electrolytes is a crucial issue for long term SOFCs stability and performances. In this study, chemical reactivity between selected cathodic materials and the ionic conducting melilite La{sub 1.50}Sr{sub 0.50}Ga{sub 3}O{sub 7.25} has been extensively investigated by means of X-ray powder diffraction. - Highlights: • Chemical compatibility between melilite-type gallate and cathodes for SOFCs up to 1573 K. • No reactivity observed between La{sub 0.8}Sr{sub 0.2}Fe{sub 0.8}Cu{sub 0.2}O{sub 3−d} and La{sub 1.50}Sr{sub 0.50}Ga{sub 3}O{sub 7.25}. • Reactivity observed between La{sub 0.80}Sr{sub 0.20}MnO{sub 3−d} and La{sub 1.50}Sr{sub 0.50}Ga{sub 3}O{sub 7.25}. • Significant reactivity observed between La{sub 2}NiO{sub 4+d} and La{sub 1.50}Sr{sub 0.50}Ga{sub 3}O{sub 7.25}.

  6. Chemical compatibility study of melilite-type gallate solid electrolyte with different cathode materials

    International Nuclear Information System (INIS)

    Chemical reactivity between cathodes and electrolytes is a crucial issue for long term SOFCs stability and performances. In this study, chemical reactivity between selected cathodic materials and the ionic conducting melilite La1.50Sr0.50Ga3O7.25 has been extensively investigated by X-ray powder diffraction in a wide temperature range (up to 1573 K). Perovskite-type La0.8Sr0.2MnO3−d and La0.8Sr0.2Fe0.8Cu0.2O3−d and K2NiF4-type La2NiO4+d were selected as cathode materials. The results of this study allow identifying the most suitable electrode material to be used in combination with the melilite-type gallate electrolyte and set the basis for future work on this novel system. - Graphical abstract: Chemical reactivity between cathodes and electrolytes is a crucial issue for long term SOFCs stability and performances. In this study, chemical reactivity between selected cathodic materials and the ionic conducting melilite La1.50Sr0.50Ga3O7.25 has been extensively investigated by means of X-ray powder diffraction. - Highlights: • Chemical compatibility between melilite-type gallate and cathodes for SOFCs up to 1573 K. • No reactivity observed between La0.8Sr0.2Fe0.8Cu0.2O3−d and La1.50Sr0.50Ga3O7.25. • Reactivity observed between La0.80Sr0.20MnO3−d and La1.50Sr0.50Ga3O7.25. • Significant reactivity observed between La2NiO4+d and La1.50Sr0.50Ga3O7.25

  7. Cathode for primary elements with solid electrolyte having conductance through silver ions

    Energy Technology Data Exchange (ETDEWEB)

    Koller, A.; Antonin, V.; Pavlik, I.

    1982-04-15

    The proposed cathode contains 50-100% iode complex of ferrocene with general formula Q x nI/sub 2/, where Q--Fe (C/sub 5/H/sub 5/)/sub 2/, n = 3-15. In order to increase electrical conductance and to decrease polarization, one can add to the active mass 0.1-15% of graphite, SiC, MoSi/sub 2/, metal Ti and W and/or 0.1-50% of solid electrolyte. This cathode only contains about 7% of inactive material. It is recommended in particular that a set Fe (C/sub 5/H/sub 5/)/sub 2/ x 10 I/sub 2/ be used which is obtained by interaction of hot solutions of ferrocene and iodine in CC1/sub 4/ with subsequent washing and drying of the obtained product.

  8. Compatibility of lithium difluoro(sulfato)borate-based electrolyte for LiMn{sub 2}O{sub 4} cathode

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shiyou; Liu, Jinliang; Li, Lingxia; Li, Xiaopeng; Jing, Jie; Cui, Xiaoling, E-mail: xlcuilw@163.com

    2015-03-01

    Highlights: • LiBF{sub 2}SO{sub 4} was investigated as a novel salt for advanced lithium-ion batteries. • LiBF{sub 2}SO{sub 4}-EC/DEC shows excellent film-forming characteristic on the surface of LiMn{sub 2}O{sub 4}. • LiBF{sub 2}SO{sub 4}-based electrolyte has good compatibility with LiMn{sub 2}O{sub 4} cathode. - Abstract: Lithium difluoro(sulfato)borate (LiBF{sub 2}SO{sub 4}) is investigated as a lithium salt for non-aqueous electrolytes for LiMn{sub 2}O{sub 4} cathode in lithium-ion batteries. Inductively coupled plasma-atomic emission spectrometry analysis is used to analyze the Mn dissolution. Scanning electron microscopy and AC impedance measurements analysis are used to analyze the formation of the surface film on the surface of LiMn{sub 2}O{sub 4} cathode. These results demonstrate that LiBF{sub 2}SO{sub 4}-based electrolyte favourably facilitates the formation of an effective and conductive interface film on the cathode surface to improve the stabilization of cathode/electrolyte interface. Besides, LiMn{sub 2}O{sub 4} cells using LiBF{sub 2}SO{sub 4}-based electrolyte exerts several advantages, such as stable cycling performance, low cell impedance, low polarization resistance, and good rate performance. It suggests that LiBF{sub 2}SO{sub 4}-based electrolyte has good compatibility with LiMn{sub 2}O{sub 4} cathode, and LiBF{sub 2}SO{sub 4} would be a very promising lithium salt for LiMn{sub 2}O{sub 4} cathode in lithium-ion batteries.

  9. 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.

  10. 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.

  11. 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.

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

    Science.gov (United States)

    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.

  13. 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......, consisting of a Nieyttria stabilized zirconia (YSZ) anode support, a Niescandia-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...... 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...

  14. 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.

  15. Cycleability of sulfurized polyacrylonitrile cathode in carbonate electrolyte containing lithium metasilicate

    Science.gov (United States)

    Wu, Borong; Chen, Feibiao; Mu, Daobin; Liao, Weilin; Wu, Feng

    2015-03-01

    The electrochemical performance of the sulfurized polyacrylonitrile (SPAN)/Li cell affected by the Li2SiO3 particles that added between cathode and separator in the assembly process is studied. Fast capacity decay happens to the base SPAN/Li cell without Li2SiO3 due to deactivation of sulfur and side reactions etc.. However, the decay is obviously mitigated in the presence of Li2SiO3. Reversible capacity retention of 79% can be achieved after 100 cycles at 0.5C, while it is less than 10% for its counterpart. XPS and TEM measurements are conducted and the result indicates a positive effect of Li2SiO3 on the inhibition of side reactions, because Li2SiO3 can hold the dissociated sulfur substances and consume PF5/HF in the carbonate electrolyte.

  16. 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.

  17. Structure of electrolyte decomposition products on high voltage spinel cathode materials determined by in situ neutron reflectometry

    Science.gov (United States)

    Browning, Jim; Veith, Gabriel; Baggetto, Loic; Dudney, Nancy; Tenhaeff, Wyatt

    2012-02-01

    Interfacial reactions on electrical energy storage (EES) materials mediate their stability, durability, and cycleablity. Understanding these reactions in situ is difficult since they occur at the liquid-solid interface of an optically absorbing material that hinders the use of techniques such as infra-red spectroscopy. Furthermore, since the interfaces involve liquids classic vacuum-based analytical methods can only probe reaction products, which are stable under vacuum. Here, we present the results of an in situ neutron reflectometry study detailing the formation of a thick solid-electrolyte interphase (SEI) on a high voltage spinel cathode material. The cathode/electrolyte system used in this study is a LiMn1.5Ni0.5O4 thin film subjected to a 1.2 molar LiPF6 in 1:1 ethylene carbonate - dimethyl carbonate electrolyte solution.

  18. 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.

  19. Micellar cathodes from self-assembled nitroxide-containing block copolymers in battery electrolytes.

    Science.gov (United States)

    Hauffman, Guillaume; Maguin, Quentin; Bourgeois, Jean-Pierre; Vlad, Alexandru; Gohy, Jean-François

    2014-01-01

    This contribution describes the synthesis of block copolymers containing electrochemically active blocks, their micellization, and finally their use as micellar cathodes in a lithium battery. The self-assembly of the synthesized poly(styrene)-block-poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl methacrylate) (PS-b-PTMA) diblock copolymers is realized in a typical battery electrolyte made of 1 m lithium trifluoromethanesulfonate dissolved in a mixture of ethylene carbonate/diethyl carbonate/dimethyl carbonate(1:1:1, in volume). Dynamic light scattering and atomic force micro-scopy indicate the formation of well-defined spherical micelles with a PS core and a PTMA corona. The electrochemical properties of those micelles are further investigated. Cyclic voltammograms show a reversible redox reaction at 3.6 V (vs Li(+) /Li). The charge/discharge profiles indicate a flat and reversible plateau around 3.6 V (vs Li(+) /Li). Finally, the cycling performances of the micellar cathodes are demonstrated. Such self-assembled block copolymers open new opportunities for nanostructured organic radical batteries. PMID:24127365

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

    International Nuclear Information System (INIS)

    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 Hβ (486.13 nm) shows that plasma discharges are characterized by the electron number density of about 1.4 × 1021 m−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 MoO3

  1. Statistical investigation on the role of supporting electrolytes during NTA degradation on BDD anodes.

    Science.gov (United States)

    Wu, Jingyu; Du, Xiaoming; He, Zhenzhu; Zhang, Chunyong; Fu, Degang

    2016-03-01

    This work reported a comparative study on the electrochemical incineration of nitrilotriacetic acid (NTA) in the presence of different supporting electrolytes (Na2SO4 and NaCl). Galvanostatic electrolyses were conducted in an undivided electrochemical cell containing boron-doped diamond (BDD) anode and platinum cathode. Initial solution pH, flow rate, applied current density, and supporting electrolyte concentration were selected as variables, besides the mineralization efficiency of NTA that was selected as response. Central composite rotatable design and response surface methodology were employed here to examine the statistical significance of the selected variables, as well as to determine the optimal conditions of the degradation process. Under the same operating conditions, two regression models were thus constructed to illustrate the differing impact of supporting electrolytes in BDD anode cells. The kinetics for NTA degradation followed different reaction orders for the two scenarios (in the absence and presence of NaCl), indicating the complex interaction between hydroxyl radicals and active chlorine. Despite this, the experimental results demonstrated that effective mineralization of NTA might also be achieved in the presence of chlorides (of lower concentrations). Besides, in the case of chlorides, the average mass transfer coefficient of the system was found to be strongly dependent on the initial solution pH. Lastly, a plausible reaction sequence concerning the electrolytic oxidation of NTA in chloride media was also proposed. PMID:26578372

  2. Influence of (La,Sr)MnO3+δ cathode composition on cathode/electrolyte interfacial structure during long-term operation of solid oxide fuel cells

    Science.gov (United States)

    Matsui, Toshiaki; Mikami, Yuichi; Muroyama, Hiroki; Eguchi, Koichi

    2013-11-01

    Time-dependent events during operation of SOFCs, i.e., performance enhancement and/or deterioration, can be readily observed for the cell composed of strontium-doped lanthanum manganite (LSM) cathode and yttria-stabilized zirconia (YSZ) electrolyte, concomitant with the change in interfacial structure of LSM/YSZ. The influence of LSM composition on the electrochemical properties and microstructure of LSM/YSZ interface during prolonged operation was investigated. Four different LSM cathodes were used and the change in microstructure, especially TPB-length, was evaluated quantitatively by a focused ion beam-scanning electron microscope (FIB-SEM). For LSM cathodes with A-site deficient compositions, the change in TPB-length had a minor contribution to the performance enhancement after 20 h of galvanostatic operation. On the other hand, for 100 h duration an increase in cathode overpotential was confirmed, accompanied with the formation of thin layer of LSM over YSZ electrolyte. A series of phenomena were triggered by the change in oxygen nonstoichiometry of LSM under polarized states. The mechanism for microstructural change was proposed and the long-term stability of LSM/YSZ interface was discussed.

  3. 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

    of the cathode were strongly dependent on the pO(2); they were significantly smaller when testing in oxygen compared to air. Microstructural analysis of the cathode/electrolyte interface of a not-tested reference cell carried out after removal of the cathode showed sharp craters on the electrolyte surface where...... the LSM particles had been located. After testing in air, these craters flattened out and decreased in size, indicating the decrease of three phase boundary length. In contrast, they remained almost unchanged after testing in oxygen giving an explanation for the observed smaller - mainly anode related...

  4. 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)

  5. 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.

  6. Kinetics and mechanism of cathodic reduction of zinc- and cadmium complexes in electrolytes containing ethanolamine and ammonia

    International Nuclear Information System (INIS)

    By the methods of plotting stationary total and partial polarograms in galvanic as well as in potentiostatic regimes the processes of cathodic zinc and cadmiun precipitation in ammonia- and ethanolamine (Etm) electrolytes have been studied versus the composition and pH of the solution. It is found that the composition of zinc- or cadmium complexes in ethanolamine-ammonia electrolytes may be presented in the form (Zn(Cd)(NHsub(3))sub(x)(Etm)sub(y)(OH)sub(z))sup(2-z), x+y+z=4; the reduction of complexes, independently of their composition, is preceded by chemical stages of partial splitting-off of ligands (or their replacement). An increase in the pH value results in appearance of insoluble salt precipitates in cadmium plating electrolytes

  7. 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.

  8. 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.

  9. Graphitic Carbon Nitride Supported Catalysts for Polymer Electrolyte Fuel Cells.

    OpenAIRE

    Mansor, N.; Jorge, A. B.; Corà, F.; Gibbs, C.; Jervis, R.; Mcmillan, P. F.; X. Wang; Brett, D. J.

    2014-01-01

    Graphitic carbon nitrides are investigated for developing highly durable Pt electrocatalyst supports for polymer electrolyte fuel cells (PEFCs). Three different graphitic carbon nitride materials were synthesized with the aim to address the effect of crystallinity, porosity, and composition on the catalyst support properties: polymeric carbon nitride (gCNM), poly(triazine) imide carbon nitride (PTI/Li(+)Cl(-)), and boron-doped graphitic carbon nitride (B-gCNM). Following accelerated corrosion...

  10. 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

  11. Actinide-Lanthanide separation by an electrolytic method in molten salt media: feasibility assessment of a renewed liquid cathode

    International Nuclear Information System (INIS)

    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)

  12. A comparison of the electrode/electrolyte reaction at elevated temperatures for various Li-ion battery cathodes

    Science.gov (United States)

    MacNeil, D. D.; Lu, Zhonghua; Chen, Zhaohui; Dahn, J. R.

    Differential scanning calorimetry (DSC) was used to compare the thermal stability of charged cathodes in 1 M LiPF 6 EC/DEC electrolyte. Seven possible cathode materials for lithium-ion batteries (LiCoO 2, LiNiO 2, LiNi 0.8Co 0.2O 2, Li 1+ xMn 2- xO 4, LiNi 0.7Co 0.2Ti 0.05Mg 0.05O 2, Li[Ni 3/8Co 1/4Mn 3/8]O 2, and LiFePO 4) were tested under the same conditions. Welded stainless steel DSC sample tubes, that ensured no weight loss during analysis, were used for these measurements, making them reliable. A consideration of these DSC results and the known electrochemical properties of the cathodes may assist the selection of the most suitable lithium-ion cathode material for use in a particular application.

  13. Direct surface modification of high-voltage LiCoO2 cathodes by UV-cured nanothickness poly(ethylene glycol diacrylate) gel polymer electrolytes

    International Nuclear Information System (INIS)

    Highlights: • Direct surface modification of high-voltage LCO cathode by UV-cured PEGDA GPE. • Conformal PEGDA nanocoating layer is formed on LCO surface. • Preformed architecture of LCO cathode is not disrupted by PEGDA coating layer. • PEGDA-LCO cathode improves high-voltage cycling performance and thermal stability. • PEGDA nanocoating layer serves as a new ion-conductive protection film. -- Abstract: In the development of high-voltage lithium-ion batteries, unwanted interfacial side reactions between delithiated cathode materials and liquid electrolytes pose a formidable challenge that needs to be urgently resolved. In this study, as a simple and effective approach to improve cell performance and thermal stability of high-voltage cells, we demonstrate direct surface modification of a cathode by UV-cured nanothickness poly(ethylene glycol diacrylate) (PEGDA) gel polymer electrolyte (GPE). Herein, the UV-crosslinking of EGDA oligomers is conducted directly on as-formed cathode (LiCoO2 (LCO) is chosen as a model system), instead of application to LCO powders. This unusual coating process allows the successful formation of the conformal PEGDA nanocoating layer on the LCO surface without disrupting the preformed physical architecture of the LCO cathode (specifically, electronic networks and porous structure to be filled with liquid electrolyte). Owing to the structural novelty, the PEGDA-coated LCO cathode improves the cycling performance of high-voltage (=4.4 V) cells and suppresses the exothermic reaction between the delithiated LCO and liquid electrolyte, as compared to the pristine LCO cathode. These results underline that the conformal PEDGDA nanocoating layer proposed herein acts as a new ion-conductive protection film that effectively mitigates the undesired interfacial side reactions

  14. Highly Active and Durable Co-Doped Pt/CCC Cathode Catalyst for Polymer Electrolyte Membrane Fuel Cells

    International Nuclear Information System (INIS)

    Highlights: •Co-doped Pt core–shell type catalyst having 0.75 nm thick Pt shell is synthesized. •Co-doped Pt exhibited mass activity of 0.44 A mgPt−1 at 0.9 ViR-free. •Co-doped Pt cathode catalyst showed high stability under cycling conditions. •Co-doped Pt catalyst showed only 16% power density loss after 30,000 cycles. •The enhanced stability is due to the increase in onset potential for PtO2 formation. -- Abstract: Cathode catalyst based on Co-doped Pt deposited on carbon composite catalyst (CCC) support with high measured activity and stability under potential cycling conditions for polymer electrolyte membrane (PEM) fuel cells was developed in this study. The catalyst was synthesized through platinum deposition on Co-doped CCC support containing pyridinic-nitrogen active sites followed by controlled heat-treatment. High resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) studies confirmed uniform Pt deposition (Pt/CCC catalyst, dPt = 2 nm) and formation of Co-doped Pt/CCC catalyst (dPt = 5.4 nm) respectively. X-ray energy dispersive spectrometry (XEDS) line-scan studies showed the formation of Co-core Pt-shell type catalyst with a Pt-shell thickness of ∼0.75 nm. At 0.9 ViR-free, the Co-doped Pt/CCC catalyst showed initial mass activity of 0.44 A mgPt−1 and 0.25 A mgPt−1 after 30,000 potential cycles between 0.6 and 1.0 V corresponding to an overall measured activity loss of 42.8%. The commercial Pt-Co/C showed initial mass activity of 0.38 A mgPt−1 and ∼70% loss of activity after 30,000 cycles. The enhanced catalytic activity at high potentials and stability of mass activity for the Co-doped Pt/CCC catalyst are attributed to the formation of compressive Pt lattice catalyst due to Co doping. The Co-doped Pt/CCC showed stable open circuit potential close to 1.0 V under H2-air with an initial power density of 857 mW cm−2 and only 16% loss after 30,000 cycles. Catalyst durability studies performed between 0

  15. Behaviour of the 1-Ascorbic as supporting Electrolyte. Influence of the Magnesium Ion

    International Nuclear Information System (INIS)

    The behaviour of 1-ascorbic acid, as supporting electrolyte of the uranyl ion in a 01-0.7 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 Mg2+ 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

  16. Failure analysis of electrolyte-supported solid oxide fuel cells

    Science.gov (United States)

    Fleischhauer, Felix; Tiefenauer, Andreas; Graule, Thomas; Danzer, Robert; Mai, Andreas; Kuebler, Jakob

    2014-07-01

    For solid oxide fuel cells (SOFCs) one key aspect is the structural integrity of the cell and hence its thermo mechanical long term behaviour. The present study investigates the failure mechanisms and the actual causes for fracture of electrolyte supported SOFCs which were run using the current μ-CHP system of Hexis AG, Winterthur - Switzerland under lab conditions or at customer sites for up to 40,000 h. In a first step several operated stacks were demounted for post-mortem inspection, followed by a fractographic evaluation of the failed cells. The respective findings are then set into a larger picture including an analysis of the present stresses acting on the cell like thermal and residual stresses and the measurements regarding the temperature dependent electrolyte strength. For all investigated stacks, the mechanical failure of individual cells can be attributed to locally acting bending loads, which rise due to an inhomogeneous and uneven contact between the metallic interconnect and the cell.

  17. Carbon dioxide electrolysis with solid oxide electrolyte cells for oxygen recovery in life support systems

    Science.gov (United States)

    Isenberg, Arnold O.; Cusick, Robert J.

    1988-01-01

    The direct electrochemical reduction of carbon dioxide (CO2) is achieved without catalysts and at sufficiently high temperatures to avoid carbon formation. The tubular electrolysis cell consists of thin layers of anode, electrolyte, cathode and cell interconnection. The electrolyte is made from yttria-stabilized zirconia which is an oxygen ion conductor at elevated temperatures. Anode and cell interconnection materials are complex oxides and are electronic conductors. The cathode material is a composite metal-ceramic structure. Cell performance characteristics have been determined using varying feed gas compositions and degrees of electrochemical decomposition. Cell test data are used to project the performance of a three-person CO2-electrolysis breadboard system.

  18. Effect of electrolytes on cataphoretically deposited LaB6 cathodes

    Science.gov (United States)

    Khairnar, Rajendra S.; Joag, D. S.; Kulkarni, S. K.; Nigavekar, A. S.; Kanitkar, P. L.

    1984-09-01

    Various electrolytes were used to deposit LaB6 on carburized tantalum by the cataphoretic method. The effect of four electrolytes viz., HCl, NH4NO3, La(NO3)3, and HNO3 on LaB6 coatings has been investigated. It is observed that use of HCl as an electrolyte provides LaB6 coatings with small grain size, low porosity, good adhesion, and ability to withstand a large number of thermal shocks. These properties make HCl the most suitable electrolyte for cataphoretic deposition of LaB6 for thermionic emission.

  19. Graphitic Carbon Nitride Supported Catalysts for Polymer Electrolyte Fuel Cells.

    Science.gov (United States)

    Mansor, Noramalina; Jorge, A Belen; Corà, Furio; Gibbs, Christopher; Jervis, Rhodri; McMillan, Paul F; Wang, Xiaochen; Brett, Daniel J L

    2014-04-01

    Graphitic carbon nitrides are investigated for developing highly durable Pt electrocatalyst supports for polymer electrolyte fuel cells (PEFCs). Three different graphitic carbon nitride materials were synthesized with the aim to address the effect of crystallinity, porosity, and composition on the catalyst support properties: polymeric carbon nitride (gCNM), poly(triazine) imide carbon nitride (PTI/Li(+)Cl(-)), and boron-doped graphitic carbon nitride (B-gCNM). Following accelerated corrosion testing, all graphitic carbon nitride materials are found to be more electrochemically stable compared to conventional carbon black (Vulcan XC-72R) with B-gCNM support showing the best stability. For the supported catalysts, Pt/PTI-Li(+)Cl(-) catalyst exhibits better durability with only 19% electrochemical surface area (ECSA) loss versus 36% for Pt/Vulcan after 2000 scans. Superior methanol oxidation activity is observed for all graphitic carbon nitride supported Pt catalysts on the basis of the catalyst ECSA.

  20. In-situ Coating of Cathode by Electrolyte Additive for High-voltage Performance of Lithium-ion Batteries

    International Nuclear Information System (INIS)

    Highlights: • In-situ formation of interface films on LiCoO2 surface by electrolyte additive. • Thickness-tunable interface films is obtained by adding different concentrations of BMP additive. • High-voltage cycling performance (4.5 V) is closely associated with the thickness of the interface film. • 0.5% BMP electrolyte additive shows superior high-voltage cycleability. - Abstract: We have previously demonstrated that N,N′-4,4′-diphenylmethane-bismaleimide (BMI) as an electrolyte additive enhances the high-voltage performance of lithium-ion batteries by electrochemically forming an interface film on cathode surface. In order to obtain a comprehensive understanding of the bismaleimide-based additives, 2,2′-Bis[4-(4-maleimidophenoxy) phenyl]propane (BMP), which is more compatible with electrolyte than BMI, is studied as a new electrolyte additive. LiCoO2 is chosen as the typical cathode material. Firstly, the structure of interface films on LiCoO2 surface is studied with different concentrations of BMP additive. The morphology, thickness and chemical composition of the interface film are characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS) respectively. The oxidation potential of BMP is measured by linear sweep voltammetry (LSV). Secondly, how the interface films influence the high-voltage cycling performance of LiCoO2/Li batteries is studied. AC impedance measurements (EIS), X-ray diffraction (XRD) and discharge profile analysis are used to further clarify the mechanism. For the first time, we find that thickness-tunable interface films could be generated on LiCoO2 surface by adding different concentrations of BMP additives in electrolyte. Also, the high-voltage cycling performance of the corresponding LiCoO2/Li batteries is closely associated with the thickness of the interface film. Optimized amount of BMP additive (0.5% w/v in our work) presents superior high

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. 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.

  3. 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.

  4. Specific features of an electric discharge operating between an electrolytic anode and a metal cathode

    Energy Technology Data Exchange (ETDEWEB)

    Gaisin, A. F.; Sarimov, L. R. [Kazan State Technical University (Russian Federation)

    2011-06-15

    Results are presented from experimental studies of a high-current electric discharge operating between an St45 steel cathode and a service water anode in a wide range of air pressures. Peculiarities of discharge ignition and specific features of cathode and anode spots were revealed. The behavior of the current density on a service water anode was investigated for the first time. Comparison of the current densities j on the steel cathode and service water anode shows that, in the parameter range under study, Hehl's law is not satisfied on the water anode. The two-dimensional distribution of the potential inside and on the surface of the service water anode was measured.

  5. Specific features of an electric discharge operating between an electrolytic anode and a metal cathode

    Science.gov (United States)

    Gaisin, A. F.; Sarimov, L. R.

    2011-06-01

    Results are presented from experimental studies of a high-current electric discharge operating between an St45 steel cathode and a service water anode in a wide range of air pressures. Peculiarities of discharge ignition and specific features of cathode and anode spots were revealed. The behavior of the current density on a service water anode was investigated for the first time. Comparison of the current densities j on the steel cathode and service water anode shows that, in the parameter range under study, Hehl's law is not satisfied on the water anode. The two-dimensional distribution of the potential inside and on the surface of the service water anode was measured.

  6. 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.

  7. Solid state cathode materials for secondary magnesium-ion batteries that are compatible with magnesium metal anodes in water-free electrolyte

    Science.gov (United States)

    Crowe, Adam J.; Bartlett, Bart M.

    2016-10-01

    With high elemental abundance, large volumetric capacity, and dendrite-free metal deposition, magnesium metal anodes offer promise in beyond-lithium-ion batteries. However, the increased charge density associated with the divalent magnesium-ion (Mg2+), relative to lithium-ion (Li+) hinders the ion-insertion and extraction processes within many materials and structures known for lithium-ion cathodes. As a result, many recent investigations incorporate known amounts of water within the electrolyte to provide temporary solvation of the Mg2+, improving diffusion kinetics. Unfortunately with the addition of water, compatibility with magnesium metal anodes disappears due to forming an ion-insulating passivating layer. In this short review, recent advances in solid state cathode materials for rechargeable magnesium-ion batteries are highlighted, with a focus on cathode materials that do not require water contaminated electrolyte solutions for ion insertion and extraction processes.

  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. 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.

  10. Polymer Electrolyte Fuel Cells Employing Heteropolyacids as Redox Mediators for Oxygen Reduction Reactions: Pt-Free Cathode Systems.

    Science.gov (United States)

    Matsui, Toshiaki; Morikawa, Eri; Nakada, Shintaro; Okanishi, Takeou; Muroyama, Hiroki; Hirao, Yoshifumi; Takahashi, Tsuyoshi; Eguchi, Koichi

    2016-07-20

    In this study, the heteropolyacids of H3+xPVxMO12-xO40 (x = 0, 2, and 3) were applied as redox mediators for the oxygen reduction reaction in polymer electrolyte fuel cells, of which the cathode is free from the usage of noble metals such as Pt/C. In this system, the electrochemical reduction of heteropolyacid over the carbon cathode and the subsequent reoxidation of the partially reduced heteropolyacid by exposure to the dissolved oxygen in the regenerator are important processes for continuous power generation. Thus, the redox properties of catholytes containing these heteropolyacids were investigated in detail. The substitution quantity of V in the heteropolyacid affected the onset reduction potential as well as the reduction current density, resulting in a difference in cell performance. The chemical composition of heteropolyacid also had a significant impact on the reoxidation property. Among the three compounds, H6PV3Mo9O40 was the most suitable redox mediator. Furthermore, the pH of the catholyte was found to be the crucial factor in determining the reoxidation rate of partially reduced heteropolyacid as well as cell performance. PMID:27348019

  11. Bifunctional, Carbon-Free Nickel/Cobalt-Oxide Cathodes for Lithium-Air Batteries with an Aqueous Alkaline Electrolyte

    International Nuclear Information System (INIS)

    Highlights: • High activity bi-functional catalyst combination for ORR and OER . • An optimum ratio of high active bi-functional catalysts was found. • Novel electrodes without carbon to avoid carbon corrosion during OER mode. • EIS model for OER describes influence of a growing oxide layers. • Long-term test exhibited an excellent long-term stability over 1200 cycles. - Abstract: Lithium-air batteries with an aqueous alkaline electrolyte promise a very high practical energy density and capacity. These batteries are mainly limited by high overpotentials on the bifunctional cathode during charge and discharge. To reduce overpotentials the bifunctional cathode of such batteries must be improved significantly. Nickel is relatively inexpensive and has a good catalytic activity in alkaline media. Co3O4 was found to be a promising metal oxide catalyst for oxygen evolution in alkaline media but it has a low electronic conductivity. On the other hand since nickel has a good electronic conductivity Co3O4 can be added to pure nickel electrodes to enhance performance due to a synergetic effect. Due to the poor stability of carbon materials at high anodic potentials, gas diffusion electrodes were prepared without carbon to improve especially long-term stability. Gas diffusion electrodes were electrochemically investigated in a half cell. In addition, cyclic voltammogrametry (CV) and electrochemical impedance spectroscopy (EIS) were carried out. SEM was used for the physical and morphological investigations. Investigations showed that electrodes containing 20 wt.% Co3O4 exhibited the highest performance

  12. H2O2 detection analysis of oxygen reduction reaction on cathode and anode catalysts for polymer electrolyte fuel cells

    Science.gov (United States)

    Kishi, Akira; Shironita, Sayoko; Umeda, Minoru

    2012-01-01

    The generation percentage of H2O2 during oxygen reduction reaction (ORR) at practical powder electrocatalysts was evaluated using a scanning electrochemical microscope (SECM). We employed a porous microelectrode that contains electrocatalysts, namely, Pt/C, Pt-Co/C, and Pt-Ru/C as the oxygen reduction electrode of the SECM, and the Pt microelectrode was used as the H2O2 detector. First, the H2O2 generation amount at Pt/Cs was measured by changing the Pt loading amount. A Pt/C with a higher Pt loading has a higher ORR activity and generates a larger amount of H2O2. However, the percentage of H2O2 generated with respect to the ORR is the same regardless of the Pt loading amount. Next, H2O2 generation is markedly suppressed at the Pt-Co/C and Pt-Ru/C in the potential ranges of practical fuel cell cathode and anode, respectively. This explains that the Pt-Co/C is effective when used as a cathode, and the anode Pt-Ru/C enables the reduction of the H2O2 generation even if O2 crossleak occurs in the practical polymer electrolyte fuel cell.

  13. 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...

  14. 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

    for oxidant and coolant supply, which reduces the overall size of the stack, power losses, and results in a lower system volume. In the present study, we present unique designs for an open-cathode system which offers uniform temperature distribution with a minimum temperature gradient and a uniform flow...... 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......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...

  15. The potential and challenges of thin-film electrolyte and nanostructured electrode for yttria-stabilized zirconia-base anode-supported solid oxide fuel cells

    Science.gov (United States)

    Noh, Ho-Sung; Yoon, Kyung Joong; Kim, Byung-Kook; Je, Hae-June; Lee, Hae-Weon; Lee, Jong-Ho; Son, Ji-Won

    2014-02-01

    Thin-film electrolytes and nanostructured electrodes are essential components for lowering the operation temperature of solid oxide fuel cells (SOFCs); however, reliably implementing thin-film electrolytes and nano-structure electrodes over a realistic SOFC platform, such as a porous anode-support, has been extremely difficult. If these components can be created reliably and reproducibly on porous substrates as anode supports, a more precise assessment of their impact on realistic SOFCs would be possible. In this work, structurally sound thin-film and nano-structured SOFC components consisting of a nano-composite NiO-yttria-stabilized zirconia (YSZ) anode interlayer, a thin YSZ and gadolinia-doped ceria (GDC) bi-layer electrolyte, and a nano-structure lanthanum strontium cobaltite (LSC)-base cathode, are sequentially fabricated on a porous NiO-YSZ anode support using thin-film technology. Using an optimized cell testing setup makes possible a more exact investigation of the potential and challenges of thin-film electrolyte and nanostructured electrode-based anode-supported SOFCs. Peak power densities obtained at 500 °C surpass 500 mW cm-2, which is an unprecedented low-temperature performance for the YSZ-based anode-supported SOFC. It is found that this critical, low-temperature performance for the anode-supported SOFC depends more on the electrode performance than the resistance of the thin-film electrolyte during lower temperature operation.

  16. 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....... Two arcs correspond to the cathode contribution: a middle range frequency one (charge transfer) and a low frequency one (oxygen dissociation/adsorption). The area specific resistances (ASRs) of both contributions increase when decreasing the oxygen partial pressure. The low frequency arc...

  17. Improving high voltage stability of lithium cobalt oxide/graphite battery via forming protective films simultaneously on anode and cathode by using electrolyte additive

    International Nuclear Information System (INIS)

    Highlights: • The cyclic stability of LiCoO2/graphite battery in voltage range of 3.0-4.5 V is improved by VEC. • VEC inhibits dimension change of the battery after cycling at 4.5 V cutoff voltage. • The SEI formed by VEC on cathode is able to inhibit the cobalt dissolution. • The anodic SEI formed by VEC suppresses the cobalt deposition and the electrolyte decomposition. - Abstract: We report a new finding that high voltage stability of lithium cobalt oxide (LiCoO2)/graphite battery can be improved by using vinyl ethylene carbonate (VEC) as an electrolyte additive. Charge/discharge tests demonstrate that the battery using VEC exhibits significantly improved cyclic and dimensional stability of the 053048-type LiCoO2/graphite pouch cell up to 4.5 V. The capacity retention is 87.0% and the swell value in thickness is 3.1% for the cell with 2.0 wt.% VEC after 400 cycles between 3.0 V and 4.5 V, compared to the values of 38.4% and 38.6%, respectively, for the cell without additive. The characterizations from scanning electron spectroscopy and X-ray photoelectron spectroscopy demonstrate that VEC facilitates the formation of stable solid electrolyte interfaces simultaneously on anode and cathode of the LiCoO2/graphite battery, yielding effective protections for anode and cathode and preventions of the electrolyte decomposition on both electrodes

  18. Lithium difluoro(oxalate)borate and LiBF4 blend salts electrolyte for LiNi0.5Mn1.5O4 cathode material

    Science.gov (United States)

    Zhou, Hongming; Xiao, Kaiwen; Li, Jian

    2016-01-01

    The electrochemical behaviors of lithium difluoro(oxalate)borate (LiODFB) and LiBF4 blend salts in ethylene carbonate + dimethyl carbonate + ethyl(methyl) carbonate (EC + DMC + EMC, 1:1:1, by wt.) have been investigated for LiNi0.5Mn1.5O4 cathode in lithium-ion batteries. The electric conductivity tests are utilized to examine the relationship among solution conductivity, the electrolyte composition and temperature. Through cyclic voltammetry, charge-discharge test and AC impedance measurements, we compare the capacity and cycling efficiency of LNMO cathode in different electrolyte systems at different temperatures and discharge current rates. Scanning electron microscopy (SEM) analysis and X-ray photoelectron spectroscopy (XPS) are served to analyze the surface nature of LNMO cathode after cycles at elevated temperature. These results demonstrate that LNMO cathode can exert excellent electrochemical performance with the increase of LiODFB concentration at room temperature and elevated temperature and it is found that just slight LiBF4, mixed with LiODFB as blend salts, can strikingly improve the cyclability at -20 °C, especially in high-rate cycling. Grouped together, the optimum LiODFB/LiBF4 molar ratio is around 4:1, which can present an excellent affinity to LNMO cathode in a wide electrochemical window.

  19. Phosphorus Enrichment as a New Composition in the Solid Electrolyte Interphase of High-Voltage Cathodes and Its Effects on Battery Cycling

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Pengfei; Zheng, Jianming; Kuppan, Saravanan; Li, Qiuyan; Lv, Dongping; Xiao, Jie; Chen, Guoying; Zhang, Jiguang; Wang, Chong M.

    2015-11-10

    Immersion of a solid into liquid often leads to the modification of both the structure and chemistry of surface of the solid, which subsequently affects the chemical and physical properties of the system. For the case of the rechargeable lithium ion battery, such a surface modification is termed as solid electrolyte interphase (SEI) layer, which has been perceived to play critical role for the stable operation of the batteries. However, the structure and chemical composition of SEI layer and its spatial distribution and dependence on the battery operating condition remain unclear. By using aberration corrected scanning transmission electron microscopy coupled with ultra-high sensitive energy dispersive x-ray spectroscopy, we probed the structure and chemistry of SEI layer on several high voltage cathodes. We show that layer-structured cathodes, when cycled at a high cut off voltage, can form a P-rich SEI layer on their surface, which is a direct evidence of Li-salt (LiPF6) decomposition. Our systematical investigations indicate such cathode/Li-salt side reaction shows strong dependence on structure of the cathode materials, operating voltage and temperature, indicating the feasibility of SEI engineering. These findings provide us valuable insights into the complex interface between the high-voltage cathode and the electrolyte.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Study on the stability of Li2MnSiO4 cathode material in different electrolyte systems for Li-ion batteries

    International Nuclear Information System (INIS)

    This study reports on the thorough investigation into the interaction between nanosized carbon-coated Li2MnSiO4 and various electrolytes, which has revealed significant changes of the active material after soaking in the electrolyte. Apart from the standard electrolyte salt lithium hexafluorophosphate (LiPF6), lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) and the F-free salt lithium bis-oxalatoborate (LiBOB) were used for soaking tests and compared in terms of corrosion power with Li2MnSiO4. Carbon-coated Li2MnSiO4 samples were obtained by solid-state synthesis and stored in contact with the electrolyte. The aged samples were fully characterized by means of several analytical techniques (XRD, XPS, SEM, ATR-FTIR). The results show that Li2MnSiO4 decomposes in LiPF6-based electrolyte at high temperatures, due to the formation of HF, which causes corrosion of the material and dissolution of Mn. No degradation was observed after soaking in the LiBOB-based electrolyte. The corrosion of the active material in standard electrolyte system, together with irreversible structural changes upon Li electrochemical extraction, are considered as the main reasons for the poor capacity retention upon cycling of the Li2MnSiO4-based cathode

  6. 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

    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 imp...

  7. 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...

  8. 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.

  9. Carbon Cathodes in Rechargeable Lithium-Oxygen Batteries Based on Double-Lithium-Salt Electrolytes.

    Science.gov (United States)

    Yoo, Eunjoo; Zhou, Haoshen

    2016-06-01

    The use of carbon materials as air electrodes in lithium-oxygen (Li-O2 ) batteries is known to be advantageous owing to their good conductivity and because they offer sites suitable for the reversible electrode reactions. However, the exact influence of carbon materials on the electrochemical performance of Li-O2 batteries is not clear. In this study the electrochemical performance of four different types of carbon materials (multiwalled carbon nanotubes (MWCNTs), CMK-3, graphene nanosheets (GNSs), and Ketjen Black (KB)) as air electrodes is examined. We find that a Li-O2 cell based on an electrode of multiwalled carbon nanotubes (MWCNTs) demonstrates good rate performance and cycle stability, when using LiNO3 -LiTFSI/DMSO as electrolyte. Li-O2 cells based on such MWCNT electrodes, with a cut-off capacity of 1000 mAh g(-1) at 500 mA g(-1) , can undergo around 90 cycles without obvious losses of capacity. Even when the discharge depth is increased to 2000 mA h g(-1) , stable cycling is maintained for 45 cycles at a charge potential below 4.0 V. PMID:27120298

  10. 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...

  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. 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.

  13. 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. PMID:21922094

  14. 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.

  15. 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

  16. A New Sealed Lithium-Peroxide Battery with a Co-Doped Li2O Cathode in a Superconcentrated Lithium Bis(fluorosulfonyl)amide Electrolyte

    OpenAIRE

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

    2014-01-01

    We propose a new sealed battery operating on a redox reaction between an oxide (O2−) 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 O2−/O2 2− redox reaction between o...

  17. 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...

  18. Ni-MoO2 composite cathodes for hydrogen evolution in alkaline solution: Effect of aging of the electrolyte for their electrodeposition

    Directory of Open Access Journals (Sweden)

    Jović Vladimir D.

    2013-01-01

    Full Text Available In this work the effect of aging of the electrolyte for electrodeposition of Ni-MoO2 composite coatings on their morphology (scanning electron microscopy, chemical composition (energy-dispersive X-ray spectroscopy, polarization characteristics and the “service life” test performance for the hydrogen evolution reaction (HER in 32 mass % NaOH at 90°C was investigated. Polarization characteristics and results of the “service life” test of Ni-MoO2 composite coatings obtained after different aging periods of the electrolyte for deposition (suspension of MoO2 powder particles in the solution containing 2 M NH4Cl + 0.2 M NiCl2 were compared with that recorded for De Nora’s commercial Ni+RuO2 cathode coating (DN. It was shown that aging of the electrolyte did not influence the morphology and chemical composition of Ni-MoO2 composite coatings electrodeposited under simulated conditions for their industrial production, while polarization characteristics for the HER were influenced. The best coating, obtained after 180 days of the electrolyte aging, showed completely different (layered structure of the deposit and significantly better performance than the commercial DN electrode during the “service life” test. [Projekat Ministarstva nauke Republike Srbije, br. 172054

  19. 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

  20. 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.

  1. 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 ℃.

  2. Carbon-free bifunctional cathodes for the use in Lithium - Air Batteries with an aqueous alkaline electrolyte

    OpenAIRE

    Wittmaier, Dennis; Wagner, Norbert; Friedrich, K. Andreas

    2014-01-01

    Carbon materials are widely used in gas diffusion electrodes due to their high electronic conductivity, relatively low costs and catalytic activity towards oxygen reduction reaction (ORR), the cathodic reaction during discharging. During charging a lithium-air battery the cathode is operated in oxygen evolution reaction (OER) mode. Carbon materials corrode in OER mode, this leads to degradation and a power loss of the electrode. To improve long-term stability and reduce side reactions as H2 a...

  3. 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.

  4. 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.

  5. 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.

  6. 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)

  7. 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. PMID:27184147

  8. 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.

  9. 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.

  10. Electrochemical ozone production: influence of the supporting electrolyte on kinetics and current efficiency

    International Nuclear Information System (INIS)

    The nature of the electrolyte strongly influences the electrode kinetics of the oxygen evolution reaction (OER) and electrochemical ozone production (EOP) mainly by affecting the degree of coverage by the intermediates of both processes. The anomalous behaviour of the Tafel coefficient, b, as a function of temperature was attributed to surface adsorption of the electrolyte species, and the competition between them, as well as gas bubble adherence. Comparison of the current efficiencies of the EOP, PHIEOP, determined for different temperatures and supporting electrolyte compositions, showed the presence of fluorinated anions increases PHIEOP. The influence of the anion nature on PHIEOP, when analysed in the light of the proposed electrode mechanism, reveals introduction into the electrolyte of anions having a high electronegativity changes the double layer structure resulting in an increase of surface concentration of the active centres leading to EOP. The inhibition of the OER in the high overpotential domain during EOP provoked by fluoro-anion adsorption is supported by the activation energy data. In situ surface characterisation before and after EOP investigation revealed that even under drastic conditions (high current density, low interfacial pH) β-PbO2 can be considered an inert electrode material

  11. 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.

  12. 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.

  13. Low Temperature Fabrication of Cathode-Supported Tubular Solid Oxide Fuel Cell by Co-Fire Process%低温共烧结制备阴极支撑管式固体氧化物燃料电池

    Institute of Scientific and Technical Information of China (English)

    熊保; 韩敏芳

    2011-01-01

    采用挤出成型法制备锰酸锶镧-氧化钇稳定氧化锆(LSM-YSZ)阴极支撑管,利用浸渍-提拉泥浆涂覆法在LSM-YSZ阴极支撑管上制备了LSM-YSZ阴极功能层、YSZ电解质和NiO-YSZ阳极多层薄膜,经低温一次共烧结制备阴极支撑管式单元固体氧化物燃料电池(SOFC).利用扫描电镜和电化学工作站等对单元电池的微观结构和电化学性能进行了较系统的表征,结果表明:经1220℃低温共烧结8h后,LSM-YSZ支撑体上的阴极功能层、电解质和阳极各层薄膜结合紧密,电解质薄膜致密无缺陷,厚约15 μm;以湿氢气为燃料,空气为氧化剂时,单元电池在700~800℃下的开路电压均高于1.0V,说明电解质薄膜具有足够的气密性,但阴极的低电导率和低孔隙率限制了电池的电性能.采用浸渍-提拉薄膜技术,经一次低温共烧结制备阴极支撑管式SOFC,为SOFC低成本制备奠定了基础.%Strontium doped lanthanum manganite-yttria doped zirconia ( LSM-YSZ) tubular cathode support was prepared via an extrusion method. Cathode functional layer, electrolyte and anode thin films were sequentially deposited onto the cathode support with dip-coating technique, by co-sintering of which at low temperature, a cathode-supported tubular solid oxide fuel cell (SOFC) was fabricated. The micro-structure and electrical performance of the tubular SOFC were characterized by scanning electron microscopy and electrochemical workstation, respectively. The results showed that cathode functional layer, electrolyte and anode thin films are tightly sintered to the cathode support after co-sintering at 1220℃ for 8 h, and the YSZ electrolyte film is dense enough with thickness of about 15 /nm . The open circuit voltages of the single cell tested from 700℃ to 800℃ are all above 1. 0 V with humidified H2 as fuel and air as oxi-dant, which are close to the theoretical value, indicated that the electrolyte film has enough tightness. However, the

  14. Inhomogeneous transport in model hydrated polymer electrolyte supported ultra-thin films

    OpenAIRE

    Borges, D. Damasceno; Franco, A A; Malek, K.; Gebel, G.; Mossa, S.

    2013-01-01

    Structure of polymer electrolytes membranes, e.g., Nafion, inside fuel cell catalyst layers has significant impact on the electrochemical activity and transport phenomena that determine cell performance. In those regions, Nafion can be found as an ultra-thin film, coating the catalyst and the catalyst support surfaces. The impact of the hydrophilic/hydrophobic character of these surfaces on the structural formation of the films and, in turn, on transport properties, has not been sufficiently ...

  15. 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.

  16. Oxide-supported PtCo alloy catalyst for intermediate temperature polymer electrolyte fuel cells

    OpenAIRE

    Stassi, Alessandro; Gatto, Irene; Baglio, Vincenzo; Passalacqua, Enza; Aricò, Antonino S.

    2013-01-01

    International audience A Pt-Co alloy catalyst supported on a Ta-doped Ti-oxide was investigated for the oxygen reduction reaction in a polymer electrolyte fuel cell (PEMFC) operating between 80° and 110 °C at different relative humidity (100% and 33% R.H.). A crystalline Anatase phase was obtained for the Ta-doped Ti-oxide support with BET surface area of about 150 m2/g. Pt and Pt3Co1 nanoparticles dispersed on the Ta-doped Ti-oxide showed a crystallite size of 3.9 and 2.9 nm, respectively...

  17. Protein-Support Interactions for Rationally Designed Bilirubin Oxidase Based Cathode: A Computational Study.

    Science.gov (United States)

    Matanovic, Ivana; Babanova, Sofia; Chavez, Madelaine Seow; Atanassov, Plamen

    2016-04-21

    An example of biocathode based on bilirubin oxidase (BOx) was used to demonstrate how density functional theory can be combined with docking simulations in order to study the interface interactions between the enzyme and specifically designed electrode surface. The electrode surface was modified through the adsorption of bilirubin, the natural substrate for BOx, and the prepared electrode was electrochemically characterized using potentiostatic measurements. The experimentally determined current densities showed that the presence of bilirubin led to significant improvement of the cathode operation. On the basis of the computationally calculated binding energies of bilirubin to the graphene support and BOx and the analysis of the positioning of bilirubin relative to the support and T1 Cu atom of the enzyme, we hypothesize that the bilirubin serves as a geometric and electronic extension of the support. The computational results further confirm that the modification of the electrode surface with bilirubin provides an optimal orientation of BOx toward the support but also show that bilirubin facilitates the interfacial electron transfer by decreasing the distance between the electrode surface and the T1 Cu atom. PMID:27015361

  18. A Highly Active and Alcohol-Tolerant Cathode Electrocatalyst Containing Ag Nanoparticles Supported on Graphene

    International Nuclear Information System (INIS)

    A highly active oxygen reduction reaction (ORR) catalyst was synthesized by supporting Ag nano-particles on graphene nano platelets (Ag/GNP) via ultrasound treatment. The Ag/GNP catalyzes the O2 molecule through a 4-electron reduction to water in 0.1 M KOH electrolyte. The half-wave potential for the ORR on Ag/GNP is similar to a Pt black coated electrode (i.e -0.27 V at Ag/GNP, and -0.18 V at 40% Pt/C vs.SCE). The kinetic rate for the ORR on Ag/GNP is 3.16 × 10−2 cm · s−1 at -0.4 V vs. SCE. The effect of alcohols and other impurities on the ORR catalytic activity for Ag/GNP was examined and found to be highly tolerant to methanol, ethanol and ethylene glycol. The Ag/GNP catalyst is also tolerant to tetraalkyl ammonium hydroxides; i.e. functional groups related to the chemical structure of common alkaline electrolyte membranes

  19. Performance assessment of Bi0.3Sr0.7Co0.3Fe0.7O3-δ-LSCF composite as cathode for intermediate-temperature solid oxide fuel cells with La0.8Sr0.2Ga0.8Mg0.2O3-δ electrolyte

    Science.gov (United States)

    Khaerudini, Deni S.; Guan, Guoqing; Zhang, Peng; Hao, Xiaogang; Wang, Zhongde; Xue, Chunfeng; Kasai, Yutaka; Abudula, Abuliti

    2015-12-01

    Perovskite-type Bi0.3Sr0.7Co0.3Fe0.7O3-δ (BiSCF3737) oxide with perfectly cubic structure based on the Pm-3m space group has been developed and investigated as cathode for intermediate-temperature solid oxide fuel cells (IT-SOFCs). BiSCF3737 is incorporated into (La0.6Sr0.4)0.9Co0.2Fe0.8O3±δ (LSCF) to form a composite cathode called LSCF-BiSCF. X-ray diffraction (XRD) results demonstrate that BiSCF3737 has an extremely desirable chemical compatibility with LSCF as well as with La0.8Sr0.2Ga0.8Mg0.2O3-δ (LSGM) electrolyte. The cells with LSGM electrolyte (0.5 mm thickness) and symmetrical electrodes are fabricated for electrocatalaytic activity test. Compared with the pure constituent (LSCF or BiSCF3737), the composite with optimum composition, i.e., LSCF50-BiSCF50, exhibits better electrochemical activity for oxygen reduction. The LSGM electrolyte-supported (∼300 μm thickness) cell with LSCF50-BiSCF50 composite cathode exhibits higher power densities of 0.617 and 0.802 W cm-2 at 650 and 700 °C, respectively, with humidified H2 (∼3% H2O) as the fuel and ambient air as the oxidant. Over 78 h stability test at 600 °C indicates that a little performance decrease occurs but no interfacial damage happens, suggesting that LSCF50-BiSCF50 is a potential material for IT-SOFCs.

  20. 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.

  1. Preparation and characterizations of platinum electrocatalysts supported on thermally treated CeO2–C composite support for polymer electrolyte membrane fuel cells

    International Nuclear Information System (INIS)

    Highlights: • CeO2–C composite support was prepared by a sol-gel approach with an average particle size of 2.5 nm. • The crystallinity of ceria was tuned by thermal treatment from 400 °C to 600 °C. • Well correlated Pt–ceria interaction was found for the Pt electrocatalysts in PEMFCs. - Abstract: A sol–gel approach was used to synthesize highly dispersed carbon-supported ceria composite support (CeO2–C) having an average particle size of 2.5 nm with sodium citrate as a ligand. The CeO2–C composite was then heated in N2 atmosphere at different temperatures to induce crystallinity variation. Pt electrocatalysts were prepared by the conventional ethylene glycol method using the thermally treated composite support (CeO2–C-T) and then characterized by X-ray diffraction and transmission electron microscopy. Electrochemical evaluations of Pt/CeO2–C-T catalytic activity were performed for methanol oxidation and oxygen reduction reactions. An optimized heating temperature was found at 550 °C for CeO2–C, and Pt/CeO2–C-550 demonstrated the highest mass activity of 0.71 A mg−1 for methanol oxidation (∼100% that of Pt/C-JM from Johnson Matthey) and 17 mV more positive shift of the half-wave potential for oxygen reduction relative to that of Pt/C–JM. The maximum power density of the membrane electrode assembly (MEA) with Pt/CeO2–C-550 cathode catalyst in a H2/air polymer electrolyte membrane fuel cell was 678 mW cm−2, which was 7% higher than that of MEA prepared with Pt/C–JM under identical operating conditions. Heating CeO2–C at 550 °C induced increased crystallinity without sacrificing particle agglomeration, which was beneficial for Pt dispersion (reduced particle size). Meanwhile catalytic activity was further enhanced because of Pt–metal oxide interactions and the known oxygen buffer capability of CeO2

  2. 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)

  3. Surface-Regulated Nano-SnO2/Pt3Co/C Cathode Catalysts for Polymer Electrolyte Fuel Cells Fabricated by a Selective Electrochemical Sn Deposition Method.

    Science.gov (United States)

    Nagasawa, Kensaku; Takao, Shinobu; Nagamatsu, Shin-ichi; Samjeské, Gabor; Sekizawa, Oki; Kaneko, Takuma; Higashi, Kotaro; Yamamoto, Takashi; Uruga, Tomoya; Iwasawa, Yasuhiro

    2015-10-14

    We have achieved significant improvements for the oxygen reduction reaction activity and durability with new SnO2-nanoislands/Pt3Co/C catalysts in 0.1 M HClO4, which were regulated by a strategic fabrication using a new selective electrochemical Sn deposition method. The nano-SnO2/Pt3Co/C catalysts with Pt/Sn = 4/1, 9/1, 11/1, and 15/1 were characterized by STEM-EDS, XRD, XRF, XPS, in situ XAFS, and electrochemical measurements to have a Pt3Co core/Pt skeleton-skin structure decorated with SnO2 nanoislands at the compressive Pt surface with the defects and dislocations. The high performances of nano-SnO2/Pt3Co/C originate from efficient electronic modification of the Pt skin surface (site 1) by both the Co of the Pt3Co core and surface nano-SnO2 and more from the unique property of the periphery sites of the SnO2 nanoislands at the compressive Pt skeleton-skin surface (more active site 2), which were much more active than expected from the d-band center values. The white line peak intensity of the nano-SnO2/Pt3Co/C revealed no hysteresis in the potential up-down operations between 0.4 and 1.0 V versus RHE, unlike the cases of Pt/C and Pt3Co/C, resulting in the high ORR performance. Here we report development of a new class of cathode catalysts with two different active sites for next-generation polymer electrolyte fuel cells. PMID:26412503

  4. 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.

  5. A cerium-lead redox flow battery system employing supporting electrolyte of methanesulfonic acid

    Science.gov (United States)

    Na, Zhaolin; Xu, Shengnan; Yin, Dongming; Wang, Limin

    2015-11-01

    A novel cerium-lead redox flow battery (RFB) employing Ce(IV)/Ce(III) and Pb(II)/Pb redox couples in the supporting electrolyte of methanesulfonic acid (MSA) is developed and preliminarily investigated. The RFB requires no additional catalyst and uses kinetically favorable reactions between low-cost reactants, and provides a desirable discharge voltage of approximately 1.7 V, with high average coulombic efficiency (CE) of 92% and energy efficiency (EE) of 86% over 800 cycles at 298 K. Stable cycling with an acceptable performance is achieved for a board operating temperature range of 253 K-313 K. The excellent performance obtained from the preliminary study suggests that the cerium-lead RFB promises to be applicable to large-scale energy storage for electricity grids.

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

    DEFF Research Database (Denmark)

    Hofmann, P.; Schweiger, A.; Fryda, L.;

    2007-01-01

    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...

  7. Nanostructured lanthanum manganate composite cathode

    DEFF Research Database (Denmark)

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

    2005-01-01

    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...

  8. 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.

  9. 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.

  10. Développement de cathodes performantes pour batteries lithium/air

    OpenAIRE

    Berenger, Sophie

    2014-01-01

    In this thesis, high-performance cathodes for lithium/air batteries have been investigated. The main limitations for lithium/air batteries are oxygen diffusion into the cathode and in the electrolyte and the progressive clogging of cathode pores by lithium oxide. The development of the air cathode is strongly dependant on the organic electrolyte used, thus the nature of the electrolyte has been here considered. Electrode porosity and the kind of catalyst employed influence the cathode perform...

  11. Modified carbon-free silver electrodes for the use as cathodes in lithium-air batteries with an aqueous alkaline electrolyte

    Science.gov (United States)

    Wittmaier, Dennis; Wagner, Norbert; Friedrich, K. Andreas; Amin, Hatem M. A.; Baltruschat, Helmut

    2014-11-01

    Gas diffusion electrodes with silver catalysts show a high activity towards oxygen reduction reaction in alkaline media but a rather poor activity towards oxygen evolution reaction. For the use in future lithium-air batteries with an aqueous alkaline electrolyte the activity of such electrodes must be improved significantly. As Co3O4 is a promising metal oxide catalyst for oxygen evolution in alkaline media, silver electrodes were modified with Co3O4. For comparison silver electrodes were also modified with IrO2. Due to the poor stability of carbon materials at high anodic potentials these gas diffusion electrodes were prepared without carbon support to improve especially the long-term stability. Gas diffusion electrodes were electrochemically investigated in an electrochemical half-cell arrangement. In addition to cyclic voltammograms electrochemical impedance spectroscopy (EIS) was carried out. SEM and XRD were used for the physical and morphological investigations. Investigations showed that silver electrodes containing 20 wt.% Co3O4 exhibited the highest performance and highest long-term stability. For comparison, rotating - ring - disc - electrode experiments have been performed using model electrodes with thin catalyst layers, showing that the amount of hydrogen peroxide evolved is negligible.

  12. 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.

  13. 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.

  14. 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

    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...

  15. Analysis of oxygen sources and reaction pathways of carbon support corrosion at the cathode in PEMFC using oxygen-18 DEMS

    Energy Technology Data Exchange (ETDEWEB)

    Li Wei [Department of Chemical and Biological Engineering, University of Alabama, Box 870203, Tuscaloosa AL 35487-0203 (United States); Lane, Alan M., E-mail: alane@eng.ua.ed [Department of Chemical and Biological Engineering, University of Alabama, Box 870203, Tuscaloosa AL 35487-0203 (United States)

    2010-09-01

    Oxygen gas, water used to humidify the gases, and surface oxides originated from the carbon black and catalyst preparation are the three possible oxygen sources contributing to carbon support corrosion (CSC) at the cathode in proton exchange membrane fuel cells (PEMFC). To discriminate among them, oxygen was isotopically labeled by replacing regular water with oxygen-18 ({sup 18}O) enriched water (H{sub 2}{sup 18}O, 98%) in differential electrochemical mass spectrometry (DEMS). The DEMS spectra of the cathode exhaust gases O{sub 2}, O{sup 18}O, {sup 18}O{sub 2}, CO{sub 2}, CO{sup 18}O and C{sup 18}O{sub 2} (m/z equal to 32, 34, 36, 44, 46 and 48 correspondingly), sampled by a mass spectrometer during cyclic voltammetry (potential cycled for 100-1400 mV at the rate of 10 mV s{sup -1}) and chronoamperometry, were analyzed to identify the sources of oxygen, identify mechanistic pathways, and classify the surface oxides on carbon for CSC. It was found that water is the main direct oxygen source for CSC. Water reacts with carbon to produce at least three types of carbon surface oxides, which are then further oxidized with water to produce CO{sub 2} in different potential ranges.

  16. 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.

  17. Novel high temperature proton conducting fuel cells: Production of La 0.995Sr 0.005NbO 4- δ electrolyte thin films and compatible cathode architectures

    Science.gov (United States)

    Fontaine, M.-L.; Larring, Y.; Haugsrud, R.; Norby, T.; Wiik, K.; Bredesen, R.

    For breakthrough development in solid oxide fuel cells, novel cell architectures integrating better performing materials and cost-effective manufacturing processes with potential for mass production must be realised. The present work addresses this on the basis of the recent discovery of acceptor doped rare-earth ortho-niobate proton conductors and the development of a versatile fabrication process. La 0.995Sr 0.005NbO 4- δ/NiO anodes are produced by tape-casting and co-lamination of green layers. Their porosity is finely tuned by using a pyrolyzable pore former. La 0.995Sr 0.005NbO 4- δ electrolytes are spin-coated using ceramic-based suspensions. Fully dense electrolytes with thickness ranging from 9 μm to 26 μm are obtained after sintering in air at 1350 °C. The cathode layers are then screen-printed. To match thermal expansion and to avoid chemical reaction between the functional layers, special attention is paid to the design of cathode architectures. CaTi 0.9Fe 0.1O 3- δ, La 2NiO 4+ δ and La 4Ni 3O 10 mixed oxygen ion and electron conducting oxides are investigated as either monophase or La 0.995Sr 0.005NbO 4- δ-based composite electrodes. The latter gives the whole cell an innovative "semi-monolithic" concept, which can take advantage of the chemical and mechanical stability of La 0.995Sr 0.005NbO 4- δ, as well as of inherent material integration. Most promising cell architectures are finally selected based on thermo-mechanical and chemical compatibility of all functional layers.

  18. 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

    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...

  19. 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)

  20. 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.

  1. 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.

  2. 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.

  3. Cathode materials review

    International Nuclear Information System (INIS)

    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

  4. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yu; Ding, Dong; Wei, Tao; Liu, Meilin

    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 cathodes as

  6. 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...

  7. 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.

  8. Mathematical and Physical Simulation of New Cathode Structure of Aluminum Electrolytic Cells%新型阴极结构铝电解槽的物理数学模拟

    Institute of Scientific and Technical Information of China (English)

    刘燕; 张廷安; 赵秋月; 李冲; 王洪星; 章俊; 冯乃祥

    2011-01-01

    采用相似原理指导下的水模型实验,研究新型阴极结构电解槽中阳极气体的扰动.通过高速摄影手段拍摄液面波动,得到不同操作条件下阴极结构铝电解槽水模型的液面波动图像,利用Image-Pro-Plus6.0专业图像分析软件对捕捉到的波动静态图进行处理,获得液面波动的最大高度.并用Fluent 6.2.16进一步对电解槽的阳极结构进行数学模拟.结果表明,极距的增加、电解质水平的提高、气体流量的减小,均会减小界面波动.新型阴极结构电解槽比普通阴极结构阳极气体引起的界面波动小,新型阴极结构可有效地降低极距;相同实验条件下,1/2阳极产生气体引起的界面波动振幅和普通阳极没有明显区别,而1/4阳极的减波作用较好,倒角对于界面波动的影响甚微.%Using cold water model experiments based on the principle of similitude, the level fluctuations by anode gas disturbance in an aluminum electrolysis cell were studied. By means of high-speed photography, the level fluctuation images of new cathode structure electrolytic cell of cold water model in different operate parameters were obtained. The maximum surface wave height was obtained by using the professional image analysis software Image-Pro-Plus 6.0 to deal with fluctuations in the captured static figures. Moreover, mathematical simulation on the anode structure of cell with Fluent 6.2.16 was also carried out. The results show that the fluctuation in new cathode structure water model of aluminum electrolysis is decreased significantly compared with that of normal cathode structure water model under the same experimental conditions. In the simulated water model cell with new cathode structure, interface fluctuation amplitude will be reduced significantly along with increasing of the anode cathode distance, increasing of the electrolyte level and decreasing of gas flow rate. The fluctuation amplitude caused by the gas from 1/2 anode is not

  9. Lithium-ion batteries having conformal solid electrolyte layers

    Science.gov (United States)

    Kim, Gi-Heon; Jung, Yoon Seok

    2014-05-27

    Hybrid solid-liquid electrolyte lithium-ion battery devices are disclosed. Certain devices comprise anodes and cathodes conformally coated with an electron insulating and lithium ion conductive solid electrolyte layer.

  10. Electrochemical properties of Fe and Al hydroxides as affected by different supporting electrolytes

    OpenAIRE

    Melis, Pietro; Premoli, Alessandra Maria; Solinas, Vincenzo; Deiana, Salvatore Andrea

    1984-01-01

    Potentiometric titration curves of Fe and Al hydroxides, carried out in presence of different electrolytes (KCI, Kbr, KI, KNO3, KCIO4) were elaborated by the Stern theory through a computered program. The zero points of charge (zpc), calculated from the intersection point of the titration curves at different ionic strenght, varied from pH 7.10 to pH 7.65 for Fe hydroxides and from pH 9.10 pH 9.45 for Al hydroxi des. For Fe compounds, a good match was found between the experimen...

  11. Studies on Co-based catalysts supported on modified carbon substrates for PEMFC cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, Nalini P.; Kumaraguru, Swaminatha P.; Colon-Mercado, Hector; Popov, Branko N. [Department of Chemical Engineering, University of South Carolina, Columbia, SC 29208 (United States); Kim, Hansung [Department of Chemical Engineering Yonsei University, Seoul (Korea, Republic of); Black, Timothy; Chen, Donna A. [Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208 (United States)

    2006-06-19

    Cobalt based non-precious metal catalysts were prepared by supporting cobalt-ethylene diamine complex on carbon followed by a heat treatment at elevated temperatures (800{sup o}C). Surface oxygen groups on carbon were introduced with HNO{sub 3} oxidation. Co catalysts supported on oxidized carbon showed improved activity and selectivity towards four-electron reduction of molecular oxygen. Quinone groups introduced by nitric acid treatment, in addition to increasing the dispersion of the chelate complexes, play a role in forming the active site for oxygen reduction. (author)

  12. 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

  13. 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.

  14. Experimental investigation on a polymer electrolyte membrane fuel cell (PEMFC) parallel flow field design with external two-valve regulation on cathode channels

    Science.gov (United States)

    Tong, Shijie; Bachman, John C.; Santamaria, Anthony; Park, Jae Wan

    2013-11-01

    Parallel/interdigitated/serpentine flow field PEM fuel cells have similar performance under low overvoltage operation. At higher overvoltage, interdigitated/serpentine flow field performance may exceed parallel flow field designs due to better water removal and more uniform reactant distribution by convective reactant flow in the GDL under land area, i.e. cross flow. However, serpentine flow field design suffers from high pumping losses and the risk of local flooding at channel U-bends. Additionally, interdigitated flow field designs may have higher local flooding risk in the inlet channels and relatively large pumping requirement at low current densities. In this study, a novel parallel flow field design with external two-valve regulation on the cathode was presented. Two valves introduced continuous pressure differences to two separate manifolds in the cathode that induce cross flow across the land areas. Moreover, both valves remained partially open to maintain a good water removal from flow channels. Comparative test results showed the proposed design surpasses performance of both parallel and interdigitated flow field design at operation current density of 0.7 A cm-2 or higher. The performance enhancement is 10.9% at peak power density point (0.387 W cm-2 @ 0.99 A cm-2) compared to parallel flow field taking into account pumping losses.

  15. Ni-MoO2 composite cathodes for hydrogen evolution in alkaline solution: Effect of aging of the electrolyte for their electrodeposition

    OpenAIRE

    Jović Vladimir D.; Lačnjevac Uroš Č.; Jović Borka M.; Gajić-Krstajić Ljiljana M.; Krstajić Nedeljko V.

    2013-01-01

    In this work the effect of aging of the electrolyte for electrodeposition of Ni-MoO2 composite coatings on their morphology (scanning electron microscopy), chemical composition (energy-dispersive X-ray spectroscopy), polarization characteristics and the “service life” test performance for the hydrogen evolution reaction (HER) in 32 mass % NaOH at 90°C was investigated. Polarization characteristics and results of the “service life” test of Ni-MoO2 composite coatings obtained after differ...

  16. Design and processing parameters of La2NiO4+δ-based cathode for anode-supported planar solid oxide fuel cells (SOFCs)

    Science.gov (United States)

    Jeong, Changwoo; Lee, Jong-Heun; Park, Mansoo; Hong, Jongsup; Kim, Hyoungchul; Son, Ji-Won; Lee, Jong-Ho; Kim, Byung-Kook; Yoon, Kyung Joong

    2015-11-01

    The Ruddlesden-Popper phase lanthanum nickelate, La2NiO4+δ (LNO), is successfully implemented as a strontium- and cobalt-free cathode in anode-supported planar solid oxide fuel cells (SOFCs) through systematic optimization of materials, processing and structural parameters. Chemical interaction between LNO and gadolinia-doped ceria (GDC), which leads to phase decomposition of composite cathode and significant deterioration of the electrochemical performance, is prevented by lowering the processing temperature below 1000 °C. For low-temperature fabrication process, the thermo-mechanical stability at the interface is secured by modifying the powder characteristics and inserting the adhesive interlayer. The issues associated with the electrical contact and current distribution are resolved by incorporating the perovskite La0.6Sr0.4CoO3-δ (LSC) as a current collecting layer, and the thermal stresses at the interface are relieved by constructing a gradient electrode structure. Consequently, the optimized anode-supported planar cell with an LNO-based cathode exhibits superior performance compared to the reference cell with a conventional cathode in the intermediate-temperature range, which is attributed to the enhanced interfacial process and surface reaction kinetics based on impedance analysis.

  17. Removal of contaminant gases from an electrolytic urine pretreatment process. [in spacecraft life support systems

    Science.gov (United States)

    Colombo, G. V.; Putnam, D. F.

    1977-01-01

    The effluent gas stream from an electrolytic urine pretreatment process was analyzed by gas chromatography-mass spectroscopy and wet chemical methods to determine its composition. The major constituents were identified as: hydrogen, carbon dioxide, oxygen, nitrogen, water vapor, and chlorine. The trace impurities were chlorinated light hydrocarbons, and a number of other organic impurities in the low ppm range. Several methods of removing all of the undesirable gases to levels acceptable for return to a space cabin atmosphere were investigated experimentally. A subsystem concept comprised of the following sequential unit processes and operations was successfully demonstrated: (1) raw urine scrubbing, (2) silica gel sorption, (3) dilution with cabin air, and (4) catalytic oxidation.

  18. 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.

  19. Combined current and temperature mapping in an air-cooled, open-cathode polymer electrolyte fuel cell under steady-state and dynamic conditions

    Science.gov (United States)

    Meyer, Q.; Ronaszegi, K.; Robinson, J. B.; Noorkami, M.; Curnick, O.; Ashton, S.; Danelyan, A.; Reisch, T.; Adcock, P.; Kraume, R.; Shearing, P. R.; Brett, D. J. L.

    2015-11-01

    In situ diagnostic techniques provide a means of understanding the internal workings of fuel cells so that improved designs and operating regimes can be identified. Here, for the first time, a combined current density and temperature distributed measurement system is used to generate an electro-thermal performance map of an air-cooled, air-breathing polymer electrolyte fuel cell stack operating in an air/hydrogen cross-flow configuration. Analysis is performed in low- and high-current regimes and a complex relationship between localised current density, temperature and reactant supply is identified that describes the way in which the system enters limiting performance conditions. Spatiotemporal analysis was carried out to characterise transient operations in dead-ended anode/purge mode which revealed extensive current density and temperature gradients.

  20. A novel MOCVD strategy for the fabrication of cathode in a solid oxide fuel cell: Synthesis of La{sub 0.8}Sr{sub 0.2}MnO{sub 3} films on YSZ electrolyte pellets

    Energy Technology Data Exchange (ETDEWEB)

    Toro, Roberta G., E-mail: rgtoro@unict.it [Dipartimento di Scienze Chimiche, Universita di Catania, ISMN-CNR and INSTM, UdR V.le Andrea Doria 6, I-95125 Catania (Italy); Fiorito, Davide M.R.; Fragala, Maria E. [Dipartimento di Scienze Chimiche, Universita di Catania, ISMN-CNR and INSTM, UdR V.le Andrea Doria 6, I-95125 Catania (Italy); Barbucci, Antonio; Carpanese, Maria P. [Dipartimento di Ingegneria Chimica e di Processo, Universita di Genova, and INSTM, UdR P.le Kennedy 1, I-16129 Genova (Italy); Malandrino, Graziella, E-mail: gmalandrino@dipchi.unict.it [Dipartimento di Scienze Chimiche, Universita di Catania, ISMN-CNR and INSTM, UdR V.le Andrea Doria 6, I-95125 Catania (Italy)

    2010-12-01

    Porous La{sub 0.8}Sr{sub 0.2}MnO{sub 3} (LSMO) films have been prepared by metal organic chemical vapor deposition (MOCVD) technique for solid oxide fuel cell (SOFC) applications. LSMO samples have been deposited on yttria-stabilized zirconia (YSZ) electrolyte pellets. The adopted in situ strategy involves a molten mixture consisting of the La(hfa){sub 3}.diglyme, Sr(hfa){sub 2}.tetraglyme, and Mn(tmhd){sub 3} [Hhfa = 1,1,1,5,5,5-hexafluoro-2,4-pentanedione; diglyme = bis(2-methoxyethyl)ether; tetraglyme = 2,5,8,11,14-pentaoxapentadecane; Htmhd = 2,2,6,6-tetramethyl-3,5-heptandione] precursors. It has been shown that porous LSMO films can be obtained through an accurate tuning of processing parameters, which affect the nucleation and growth processes. The structural and compositional characterizations of these films, carried out by X-ray diffraction (XRD) and energy dispersive X-ray analysis, point to the formation of a single polycrystalline La{sub 0.8}Sr{sub 0.2}MnO{sub 3} phase. The field emission scanning electron microscopy (FE-SEM) images confirm the formation of porous films. To evaluate the electrochemical activity of the cathodic films, an investigation by impedance spectroscopy (IS) has been performed.

  1. Electrolytic process for producing hydrogen peroxide

    International Nuclear Information System (INIS)

    An electrolytic process for producing hydrogen peroxide in an aqueous alkaline solution includes simultaneously passing an aqueous alkaline electrolyte and oxygen through a fluid permeable conductive cathode comprising reticulated vitreous carbon foam, separating the fluid permeable conductive cathode from an anode by a barrier and connecting the fluid permeable conductive electrode and the anode with an external power source to cause generation of hydrogen peroxide ion within the aqueous alkaline solution

  2. 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)

  3. Tantalum carbide as a novel support material for anode electrocatalysts in polymer electrolyte membrane water electrolysers

    DEFF Research Database (Denmark)

    Polonský, Jakub; Petrushina, Irina; Christensen, Erik;

    2012-01-01

    in a mixture of trifluoromethanesulfonic acid (TFMSA) and hydrogen peroxide at 130 °C. The liquid phase was subsequently analysed using ICP-MS with respect to the occurrence of ions potentially originating from the support material tested. The TaC support selected was additionally characterised...... and was equal to 0.1, 0.3, 0.5, 0.7, 0.9 and 1. The thin-film method was used for electrochemical characterisation of the electrocatalysts prepared. SEM–EDX analysis, X-ray diffraction, N2 adsorption (BET) and powder conductivity measurements were used as complementary techniques to complete characterisation...

  4. 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.

  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. Tantalum carbide as a novel support material for anode electrocatalysts in polymer electrolyte membrane water electrolysers

    OpenAIRE

    Polonský, Jakub; Petrushina, Irina; Christensen, Erik; Bouzek, K.; Prag, Carsten Brorson; Andersen, Jens Enevold Thaulov; Bjerrum, Niels

    2012-01-01

    Iridium oxide (IrO2) currently represents a state of the art electrocatalyst for anodic oxygen evolution. Since iridium is both expensive and scarce, the future practical application of this process makes it essential to reduce IrO2 loading on the anodes of PEM water electrolysers. In the present study an approach to utilising a suitable electrocatalyst support was followed. Of the materials selected from a literature review, TaC has proved to be stable under the conditions of the accelerated...

  7. Segmented cell testing for cathode parameter investigation

    Science.gov (United States)

    Tanasini, Pietro; Schuler, J. Andreas; Wuillemin, Zacharie; Ameur, Myriam L. Ben; Comninellis, Christos; Van herle, Jan

    The increasing quality and durability of solid oxide fuel cells (SOFCs) state-of-the-art materials renders the long-term testing of fuel cells difficult since considerably long equipment times are needed to obtain valuable results. Moreover, reproducibility issues are common due to the high sensitivity of the performance and degradation on the testing conditions. An original segmented cell configuration has been adopted in order to carry out four tests in parallel, thus decreasing the total experimental time and ensuring the same operating conditions for the four segments. The investigation has been performed on both anode-supported cells and symmetrical Lanthanum-Strontium Manganite-Yttria-stabilized Zirconia (LSM-YSZ) electrolyte-supported cells. In separate tests, the influence of variables like cathode thickness, current density and cathode composition on performance and degradation have been explored on anode-supported cells. Furthermore, the effect of chromium poisoning has been studied on electrolyte-supported symmetric cells by contacting one segment with a chromium-iron interconnect material. Long-term polarization of the segments is controlled with a multi-channel galvanostatic device designed in-house. Electrochemical characterization has been performed through electrochemical impedance spectroscopy (EIS) at different H 2 partial pressures, temperatures and bias current, effectively demonstrating the direct impact of each studied variable on the cell performance and degradation behavior. Segmented cell testing has been proven to be an effective strategy to achieve better reproducibility for SOFC measurements since it avoids the inevitable fluctuations found in a series of successively run tests. Moreover, simultaneous testing increased n-fold the data output per experiment, implying a considerable economy of time.

  8. Nd-nickelate solid oxide fuel cell cathode sensitivity to Cr and Si contamination

    Science.gov (United States)

    Andreas Schuler, J.; Lübbe, Henning; Hessler-Wyser, Aïcha; Van herle, Jan

    2012-09-01

    The stability of Nd-nickelate, considered as an alternative solid oxide fuel cell (SOFC) cathode material, was evaluated in this work on its tolerance towards contaminants. Symmetrical cells with Nd1.95NiO4+δ (NNO) electrodes sintered on gadolinia-doped ceria electrolyte supports were monitored over time-spans of 1000 h at 700 °C under polarization in an air-flux with deliberate chromium contamination. Impedance spectroscopy pointed out a polarization increase with time by the growth of the low frequency arc describing the electrode's oxygen reduction and incorporation processes. Post-test observations revealed polluted cathode regions with increasing amounts of Cr accumulations towards the electrolyte/cathode interface. Cr deposits were evidenced to surround active nickelate grain surfaces forming Nd-containing Cr oxides. In addition to exogenous Cr contamination, endogenous contamination was revealed. Silicon, present as impurity material in the raw NNO powder (introduced by milling during powder processing), reacts during sintering steps to form Nd-silicate phases, which decreases the active cathode surface. Nd-depletion of the nickelate, as a result of secondary phase formation with the contaminants Cr and Si (NdCrO4 and Nd4Si3O12), then triggers the thermally-induced decomposition of NNO into stoichiometric Nd2NiO4+δ and NiO. Summarized, the alternative Nd-nickelate cathode also suffers from degradation caused by pollutant species, like standard perovskites.

  9. Functionally Graded Cathodes for Solid Oxide Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Harry Abernathy; Meilin Liu

    2006-12-31

    One primary suspected cause of long-term performance degradation of solid oxide fuels (SOFCs) is the accumulation of chromium (Cr) species at or near the cathode/electrolyte interface due to reactive Cr molecules originating from Cr-containing components (such as the interconnect) in fuel cell stacks. To date, considerable efforts have been devoted to the characterization of cathodes exposed to Cr sources; however, little progress has been made because a detailed understanding of the chemistry and electrochemistry relevant to the Cr-poisoning processes is still lacking. This project applied multiple characterization methods - including various Raman spectroscopic techniques and various electrochemical performance measurement techniques - to elucidate and quantify the effect of Cr-related electrochemical degradation at the cathode/electrolyte interface. Using Raman microspectroscopy the identity and location of Cr contaminants (SrCrO{sub 4}, (Mn/Cr){sub 3}O{sub 4} spinel) have been observed in situ on an LSM cathode. These Cr contaminants were shown to form chemically (in the absence of current flowing through the cell) at temperatures as low as 625 C. While SrCrO{sub 4} and (Mn/Cr){sub 3}O{sub 4} spinel must preferentially form on LSM, since the LSM supplies the Sr and Mn cations necessary for these compounds, LSM was also shown to be an active site for the deposition of Ag{sub 2}CrO{sub 4} for samples that also contained silver. In contrast, Pt and YSZ do not appear to be active for formation of Cr-containing phases. The work presented here supports the theory that Cr contamination is predominantly chemically-driven and that in order to minimize the effect, cathode materials should be chosen that are free of cations/elements that could preferentially react with chromium, including silver, strontium, and manganese.

  10. 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.

  11. A cobalt-free SrFe 0.9Sb 0.1O 3- δ cathode material for proton-conducting solid oxide fuel cells with stable BaZr 0.1Ce 0.7Y 0.1Yb 0.1O 3- δ electrolyte

    Science.gov (United States)

    Ling, Yihan; Zhang, Xiaozhen; Wang, Songlin; Zhao, Ling; Lin, Bin; Liu, Xingqin

    A cobalt-free cubic perovskite oxide SrFe 0.9Sb 0.1O 3- δ (SFSb) is investigated as a novel cathode for proton-conducting solid oxide fuel cells (H-SOFCs). XRD results show that SFSb cathode is chemically compatible with the electrolyte BaZr 0.1Ce 0.7Y 0.1Yb 0.1O 3- δ (BZCYYb) for temperatures up to 1000 °C. Thin proton-conducting BZCYYb electrolyte and NiO-BaZr 0.1Ce 0.7Y 0.1Yb 0.1O 3- δ (NiO-BZCYYb) anode functional layer are prepared over porous anode substrates composed of NiO-BZCYYb by a one-step dry-pressing/co-firing process. Laboratory-sized quad-layer cells of NiO-BZCYYb/NiO-BZCYYb/BZCYYb/SFSb are operated from 550 to 700 °C with humidified hydrogen (∼3% H 2O) as fuel and the static air as oxidant. An open-circuit potential of 0.996 V, maximum power density of 428 mW cm -2, and a low electrode polarization resistance of 0.154 Ω cm 2 are achieved at 700 °C. The experimental results indicate that the cobalt-free SFSb is a promising candidate for cathode material for H-SOFCs.

  12. 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.

  13. Isotope separation by electrolytic amalgamation of lithium: preliminary studies

    International Nuclear Information System (INIS)

    Preliminary experiments on electrolytic amalgamation of lithium aqueous solutions were performed in order to obtain data for the design of an electrolytic cell with a moving mercury cathode. Among the two electrolytes analyzed Li OH gave best yield than Li Cl. Current concentration, current density and lithium amalgam concentration were determined. (author)

  14. Ionic liquid electrolytes as a platform for rechargeable metal-air batteries: a perspective.

    Science.gov (United States)

    Kar, Mega; Simons, Tristan J; Forsyth, Maria; MacFarlane, Douglas R

    2014-09-21

    Metal-air batteries are a well-established technology that can offer high energy densities, low cost and environmental responsibility. Despite these favourable characteristics and utilisation of oxygen as the cathode reactant, these devices have been limited to primary applications, due to a number of problems that occur when the cell is recharged, including electrolyte loss and poor efficiency. Overcoming these obstacles is essential to creating a rechargeable metal-air battery that can be utilised for efficiently capturing renewable energy. Despite the first metal-air battery being created over 100 years ago, the emergence of reactive metals such as lithium has reinvigorated interest in this field. However the reactivity of some of these metals has generated a number of different philosophies regarding the electrolyte of the metal-air battery. Whilst much is already known about the anode and cathode processes in aqueous and organic electrolytes, the shortcomings of these electrolytes (i.e. volatility, instability, flammability etc.) have led some of the metal-air battery community to study room temperature ionic liquids (RTILs) as non-volatile, highly stable electrolytes that have the potential to support rechargeable metal-air battery processes. In this perspective, we discuss how some of these initial studies have demonstrated the capabilities of RTILs as metal-air battery electrolytes. We will also show that much of the long-held mechanistic knowledge of the oxygen electrode processes might not be applicable in RTIL based electrolytes, allowing for creative new solutions to the traditional irreversibility of the oxygen reduction reaction. Our understanding of key factors such as the effect of catalyst chemistry and surface structure, proton activity and interfacial reactions is still in its infancy in these novel electrolytes. In this perspective we highlight the key areas that need the attention of electrochemists and battery engineers, in order to progress

  15. 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.

  16. Electrolytes for rechargeable lithium batteries

    International Nuclear Information System (INIS)

    There is growing interest in high specific energy lithium rechargeable batteries with improved discharge/charge cycles. Some of the promising battery systems under development are Li/CoO2, Li/V2O5 and Li/MnO2. A major factor that controls the specific performance of these batteries is the electrolyte. Recent advances made in the liquid electrolyte area for lithium high energy cathode systems are reviewed. Experimental work on the processing of solid thin film polymer electrolytes using plasticizers such as polyethylene glycol dimethoxy ether (PEGDME) and the properties such as conductivity and differential scanning calorimetry of polymer film electrolytes are presented. The advantages and the disadvantages of polymer thin film electrolytes are discussed

  17. 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

    2016-05-01

    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.

  18. 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

    2016-05-01

    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. PMID:27008979

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

    Science.gov (United States)

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

    2016-05-01

    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.

  20. 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.

  1. 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.

  2. Experimental Study on Electrolytic Dechlorination of Trichloroethene in Water at Cathode%阴极电催化还原降解水中三氯乙烯实验研究

    Institute of Scientific and Technical Information of China (English)

    权超; 鲁安怀; 李艳

    2012-01-01

    三氯乙烯是地下饮用水中的主要有机污染物之一,广泛应用于金属加工、电子和干洗等行业,由于其土壤吸附性弱、水溶性低,所以很容易在地下水中积累,严重影响人体健康.文章利用独立设计的电化学双室反应装置,进行了阴极电催化还原法降解水中三氯乙烯的实验,并选择了检测降解产物较好的DB-VRX色谱柱,探讨了不同电极电势、电子供体及用量对三氯乙烯降解效果的影响,获得了水相体系中降解三氯乙烯的最佳实验条件.当采用DB-VRX色谱柱,固定阴极电势-0.45V(vs.NHE),电子供体为甲酸0.4 g/L,三氯乙烯初始浓度约为10 mg/L时,经过44h反应,三氯乙烯的降解率达到了58.2%,并生成二氯甲烷、三氯甲烷等产物.通过GC-MSD对降解产物进行分析,提出了阴极电催化还原降解水中三氯乙烯的机理.%Trichloroethene (TCE)as one of major organic pollutants in drinking water is seriously harmful to human health due to its weak soil adsorption and limited water solubility. It is easily accumulated in underground water. Electrolytic dechlorination of TCE in water at cathode using an independent design of electrochemical experimental equipment was introduced. A better chromatographic column was chosen. Effects of electrode potential, electron donor and its dosage on TEC degradation rate were discussed. The optimum experimental conditions in water system was obtained based on series trials, with the column as DB-VRX, under the best experimental conditions of cathode potential -0.45 V(vs. NHE), formic acid as electron donor with concentration of 0.4 g/L, initial concentration of TCE 10 mg/L approximately, TCE was degraded by 58.2% after 44 h. Methylene chloride and chloroform were found during the experiment. The degradation mechanisms were discussed based on the analysis of degradation products.

  3. Salt taste inhibition by cathodal current

    OpenAIRE

    Hettinger, Thomas P.; Frank, Marion E.

    2009-01-01

    Effects of cathodal current, which draws cations away from the tongue and drives anions toward the tongue, depend on the ionic content of electrolytes through which the current is passed. To address the role of cations and anions in human salt tastes, cathodal currents of −40 to −80 µA were applied to human subjects’ tongues through supra-threshold salt solutions. The salts were sodium chloride, sodium bromide, potassium chloride, ammonium chloride, calcium chloride, sodium nitrate, sodium su...

  4. 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.

  5. Microbial fuel cell performance with non-Pt cathode catalysts

    Science.gov (United States)

    HaoYu, Eileen; Cheng, Shaoan; Scott, Keith; Logan, Bruce

    Various cathode catalysts prepared from metal porphyrines and phthalocyanines were examined for their oxygen reduction activity in neutral pH media. Electrochemical studies were carried out with metal tetramethoxyphenylporphyrin (TMPP), CoTMPP and FeCoTMPP, and metal phthalocyanine (Pc), FePc, CoPc and FeCuPc, supported on Ketjenblack (KJB) carbon. Iron phthalocyanine supported on KJB (FePc-KJB) carbon demonstrated higher activity towards oxygen reduction than Pt in neutral media. The effect of carbon substrate was investigated by evaluating FePc on Vulcan XC carbon (FePcVC) versus Ketjenblack carbon. FePc-KJB showed higher activity than FePcVC suggesting the catalyst activity could be improved by using carbon substrate with a higher surface area. With FePc-KJB as the MFC cathode catalyst, a power density of 634 mW m -2 was achieved in 50 mM phosphate buffer medium at pH 7, which was higher than that obtained using the precious-metal Pt cathode (593 mW m -2). Under optimum operating conditions (i.e. using a high surface area carbon brush anode and 200 mM PBM as the supporting electrolyte with 1 g L -1 acetate as the substrate), the power density was increased to 2011 mW m -2. This high power output indicates that MFCs with low cost metal macrocycles catalysts is promising in further practical applications.

  6. 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.

  7. 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.

  8. 片式钽电解电容器阴极石墨涂层材料的被覆条件对其电性参数的影响%Chip tantalum electrolytic capacitors Cathode Graphite coating material Coating conditions Electrical parameters Affect

    Institute of Scientific and Technical Information of China (English)

    李福成

    2012-01-01

    In this paper is Graphite material Tantalum electrolytic capacitors The manganese dioxide cathode layer Coating use as background Respectively discuss Different graphite solid content of the sample data capacity contrast Curing temperature, etc. Under the experimental conditions Graphite material Tantalum electrolytic capacitors Electrical parameters of the contrast between the impact The test results show that: Graphite solids content 5.0 ± X% 、 Curing temperature 为 165 ±y℃/45min is Graphite as the cathode material used in the top coating process conditions Sample electrical parameters improved significantly And the use of the process as a cathode material The graphite solution PH value size is very important and Affect Tremendous PH value of about 11 to 13 use the ideal parameters%本文主要以石墨材料在钽电解电容器二氧化锰阴极层上的被覆使用为背景,分别讨论了在不同石墨材料的固体含量、固化温度等实验条件下对钽电解电容器样品电性参数之间的对比影响,试验结果表明:石墨固体含量为5.0±X%、固化温度为165±y℃/45 min时为石墨作为阴极材料使用的最佳被覆工艺条件,样品电性参数明显改善.而作为阴极材料使用的过程中,发现石墨溶液的PH值大小非常重要,对样品电性的影响很大,当PH值为11 ~13左右时为理想使用参数.

  9. 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...

  10. 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。

  11. Nuclear electrolytic hydrogen

    International Nuclear Information System (INIS)

    An extensive study of hydrogen supply has recently been carried out by Ontario Hydro which indicates that electrolytic hydrogen produced from nuclear electricity could offer the lowest cost option for any future large scale hydrogen supply in the Province of Ontario, Canada. This paper provides a synopsis of the Ontario Hydro study, a brief overview of the economic factors supporting the study conclusion and discussion of a number of issues concerning the supply of electrolytic hydrogen by electric power utilities

  12. 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...... conditions were analyzed in order to identify a suitable set of EPD process parameters. The powders were deposited on a composite substrate of LCN, NiO, binder and graphite. A dense 8 μm film of lanthanum niobate supported on a porous substrate was obtained after sintering at 1200 °C. The technique was found...

  13. 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.

  14. 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

  15. 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)

  16. Structural and Electronic Transformations of Pt/C, Pd@Pt(1 ML)/C and Pd@Pt(2 ML)/C Cathode Catalysts in Polymer Electrolyte Fuel Cells during Potential-step Operating Processes Characterized by In-situ Time-resolved XAFS

    Science.gov (United States)

    Nagamatsu, Shin-ichi; Takao, Shinobu; Samjeské, Gabor; Nagasawa, Kensaku; Sekizawa, Oki; Kaneko, Takuma; Higashi, Kotaro; Uruga, Tomoya; Gayen, Sirshendu; Velaga, Srihari; Saniyal, Milan K.; Iwasawa, Yasuhiro

    2016-06-01

    The dynamic structural and electronic transformations of Pt/C, Pd@Pt(1 ML)/C, Pd@Pt(2 ML)/C cathode catalysts in polymer electrolyte fuel cells (PEFCs) during the potential-step operating processes between 0.4 and 1.4 VRHE (potential vs RHE) were characterized by in-situ (operando) time-resolved Pt LIII-edge quick-XAFS at 100 ms time-resolution. Potential-dependent surface structures and oxidation states of Pt, Pd@Pt(1 ML) and Pd@Pt(2 ML) nanoparticles on carbon at 0.4 and 1.4 VRHE were also analyzed by in-situ Pt LIII-edge and Pd K-edge quick-XAFS. The Pt, Pd@Pt(1 ML) and Pd@Pt(2 ML) nanoparticle surfaces were restructured and disordered at 1.4 VRHE, which were induced by strong Pt-O bonds as well as alloying effects. The rate constants for the changes of Pt valence, CN(Pt-Pt), CN(Pt-Pd) and CN(Pt-O) (CN: coordination number) in the potential-step operating processes were also determined and discussed in relation to the origin of oxygen reduction reaction (ORR) activities of the Pt/C, Pd@Pt(1 ML)/C and Pd@Pt(2 ML)/C cathode catalysts.

  17. 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.

  18. Operation of Thin-Film Electrolyte Metal-Supported Solid Oxide Fuel Cells in Lightweight and Stationary Stacks: Material and Microstructural Aspects

    Directory of Open Access Journals (Sweden)

    Daniel Roehrens

    2016-09-01

    Full Text Available In this study we report on the development and operational data of a metal-supported solid oxide fuel cell with a thin film electrolyte under varying conditions. The metal-ceramic structure was developed for a mobile auxiliary power unit and offers power densities of 1 W/cm2 at 800 °C, as well as robustness under mechanical, thermal and chemical stresses. A dense and thin yttria-doped zirconia layer was applied to a nanoporous nickel/zirconia anode using a scalable adapted gas-flow sputter process, which allowed the homogeneous coating of areas up to 100 cm2. The cell performance is presented for single cells and for stack operation, both in lightweight and stationary stack designs. The results from short-term operation indicate that this cell technology may be a very suitable alternative for mobile applications.

  19. 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

    2015-11-01

    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. PMID:26347905

  20. 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

    2015-11-01

    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.

  1. 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.

  2. 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......-stabilized Zirconia (YSZ) electrolyte coated with a thin layer of CGO, and YSZ electrolyte. Impedance spectra were measured to determine the polarization resistance (R,) and series resistance (R-s) on cells in a symmetric configuration. R-p of 0.19 Omega cm(2) at 600 degreesC and 0.026 Omega cm(2) at 700 degrees......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...

  3. Microbial fuel cell performance with non-Pt cathode catalysts

    Energy Technology Data Exchange (ETDEWEB)

    HaoYu, Eileen; Scott, Keith [School of Chemical Engineering and Advanced Materials, University of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU (United Kingdom); Cheng, Shaoan; Logan, Bruce [Department of Civil and Environmental Engineering, The Penn State Hydrogen Energy (H{sub 2}E) Center, Penn State University, University Park, PA 16802 (United States)

    2007-09-27

    Various cathode catalysts prepared from metal porphyrines and phthalocyanines were examined for their oxygen reduction activity in neutral pH media. Electrochemical studies were carried out with metal tetramethoxyphenylporphyrin (TMPP), CoTMPP and FeCoTMPP, and metal phthalocyanine (Pc), FePc, CoPc and FeCuPc, supported on Ketjenblack (KJB) carbon. Iron phthalocyanine supported on KJB (FePc-KJB) carbon demonstrated higher activity towards oxygen reduction than Pt in neutral media. The effect of carbon substrate was investigated by evaluating FePc on Vulcan XC carbon (FePcVC) versus Ketjenblack carbon. FePc-KJB showed higher activity than FePcVC suggesting the catalyst activity could be improved by using carbon substrate with a higher surface area. With FePc-KJB as the MFC cathode catalyst, a power density of 634 mW m{sup -2} was achieved in 50 mM phosphate buffer medium at pH 7, which was higher than that obtained using the precious-metal Pt cathode (593 mW m{sup -2}). Under optimum operating conditions (i.e. using a high surface area carbon brush anode and 200 mM PBM as the supporting electrolyte with 1 g L{sup -1} acetate as the substrate), the power density was increased to 2011 mW m{sup -2}. This high power output indicates that MFCs with low cost metal macrocycles catalysts is promising in further practical applications. (author)

  4. POLYMER ELECTROLYTE MEMBRANE FUEL CELLS

    DEFF Research Database (Denmark)

    2001-01-01

    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....... With the thermally resistant polymer, e.g., polybenzimidazole or a mixture of polybenzimidazole and other thermoplastics as binder, the carbon-supported noble metal catalyst is tape-cast onto a hydrophobic supporting substrate. When doped with an acid mixture, electrodes are assembled with an acid doped solid...

  5. All solid state lithium batteries based on lamellar garnet-type ceramic electrolytes

    Science.gov (United States)

    Du, Fuming; Zhao, Ning; Li, Yiqiu; Chen, Cheng; Liu, Ziwei; Guo, Xiangxin

    2015-12-01

    All solid-state lithium batteries are constructed by using highly conducting Ta-doped Li7La3Zr2O12 (LLZTO) as the solid electrolytes as well as the supports, coated with composite cathodes consisting of poly(vinylidene fluoride) (PVdF):LiTFSI, Ketjen Black, and carbon-coated LiFePO4 on one side and attached with Li anode on the other side. At 60 °C, the batteries show the first discharge capacity of 150 mAh g-1 at 0.05 C and 93% capacity retention after 100 cycles. As the current density increases from 0.05 C to 1 C, the specific capacity decreases from 150 mAh g-1 to 100 mAh g-1. Further elevated temperature up to 100 °C leads to further improved performance, i.e. 126 mAh g-1 at 1 C and 99% capacity retention after 100 cycles. This good performance can be attributed to the highly conducting ceramic electrolytes, the optimum electronic and ionic conducting networks in the composite cathodes, and closely contacted cathode/LLZTO interface. These results indicate that the present strategy is promising for development of high-performance solid-state Li-ion batteries operated at medium temperature.

  6. Optimization of Ferritic Steel Porous Supports for Protonic Fuel Cells Working at 600°C

    OpenAIRE

    Venkatachalam, Vinothini; Molin, Sebastian; Chen, Ming; Smirnov, I.; Larsson, P.-O.; Hendriksen, Peter Vang; Bonanos, Nikolaos

    2014-01-01

    Metal supported protonic fuel cells (PCFC) offer one major advantage over standard solid oxide fuel cells (SOFC) with oxygen conducting electrolytes, namely that the product, water, is produced on the cathode (air) side. This feature simplifies the engineering of the stack, boosts efficiency, and is particularly helpful for a porous metal supported cell because it limits the corrosion of the metal by exposure to water vapor in the anode gas.In this work, we show the effect of composition and ...

  7. 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.

  8. 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.

  9. 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. PMID:27487940

  10. 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.

  11. Mapping the anode surface-electrolyte interphase: investigating a life limiting process of lithium primary batteries.

    Science.gov (United States)

    Bock, David C; Tappero, Ryan V; Takeuchi, Kenneth J; Marschilok, Amy C; Takeuchi, Esther S

    2015-03-11

    Cathode solubility in batteries can lead to decreased and unpredictable long-term battery behavior due to transition metal deposition on the negative electrode such that it no longer supports high current. Analysis of negative electrodes from cells containing vanadium oxide or phosphorus oxide based cathode systems retrieved after long-term testing was conducted. This report demonstrates the use of synchrotron based X-ray microfluorescence (XRμF) to map negative battery electrodes in conjunction with microbeam X-ray absorption spectroscopy (μXAS) to determine the oxidation states of the metal centers resident in the solid electrolyte interphase (SEI) and at the electrode surface. Based on the empirical findings, a conceptual model for the location of metal ions in the SEI and their role in impacting lithium ion mobility at the electrode surfaces is proposed. PMID:25690846

  12. 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...

  13. 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

  14. 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.

  15. 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.

  16. Anion Solvation in Carbonate Electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhengcheng

    2015-11-16

    With the correlation between Li+ solvation and interphasial chemistry on anodes firmly established in Li-ion batteries, the effect of cation–solvent interaction has gone beyond bulk thermodynamic and transport properties and become an essential element that determines the reversibility of electrochemistry and kinetics of Li-ion intercalation chemistries. As of now, most studies are dedicated to the solvation of Li+, and the solvation of anions in carbonate-based electrolytes and its possible effect on the electrochemical stability of such electrolytes remains little understood. As a mirror effort to prior Li+ solvation studies, this work focuses on the interactions between carbonate-based solvents and two anions (hexafluorophosphate, PF6–, and tetrafluoroborate, BF4–) that are most frequently used in Li-ion batteries. The possible correlation between such interaction and the interphasial chemistry on cathode surface is also explored.

  17. A Study on the Effect of Electrolyte Thickness on Atmospheric Corrosion of Carbon Steel

    International Nuclear Information System (INIS)

    Effect of electrolyte layer thickness and increase in concentration of electrolyte during electrolyte thining on the atmospheric corrosion of carbon steel were investigated using EIS and cathodic polarization technique. The electrolyte layer thickness was controlled via two methods : one is mechanical method with microsyringe applying a different amount of electrolyte onto the metal surface to give different electrolyte thickness with the same electrolyte concentration. The other is drying method in which water layer thickness decreases through drying, causing increase in concentration of electrolyte during electrolyte thinning. In the region whose corrosion rate is controlled by cathodic reaction, corrosion rate for mechanical method is larger than that for drying method. However, for the electrolyte layers thinner than 20 ∼ 30 m, increase in concentration of electrolyte cause a higher corrosion rate for the case of the mechanical method compared with that of drying method. For a carbon steel covered with 0.1M Na2SO4, maximum corrosion rate is found at an electrolyte thickness of 45 ∼ 55 μm for mechanical method. However, maximum corrosion rate is found at an electrolyte thickness of 20 ∼ 35 μm for drying method. The limiting current is inversely proportional to electrolyte thickness for electrolyte thicker than 20 ∼ 30 μm. However, further decrease of the electrolyte thickness leads to an electrolyte thickness-independent limiting current reagion, where the oxygen rate is controlled by the solvation of oxygen at the electrolyte/gas interface. Diffusion limiting current for drying method is smaller compared with that for mechanica control. This can be attributed to decreasing in O2 solubility caused by increase in concentration of electrolyte during electrolyte thining

  18. A cobalt-free SrFe{sub 0.9}Sb{sub 0.1}O{sub 3-{delta}} cathode material for proton-conducting solid oxide fuel cells with stable BaZr{sub 0.1}Ce{sub 0.7}Y{sub 0.1}Yb{sub 0.1}O{sub 3-{delta}} electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Ling, Yihan; Zhao, Ling; Lin, Bin; Liu, Xingqin [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China (USTC), Hefei, Anhui 230026 (China); Zhang, Xiaozhen [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China (USTC), Hefei, Anhui 230026 (China); Key Laboratory of Jiangxi Universities for Inorganic Membranes, School of Material Science and Engineering, Jingdezhen Ceramic Institute, Jingdezhen 333001 (China); Wang, Songlin [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China (USTC), Hefei, Anhui 230026 (China); Department of Mechanical Engineering, Tongling University (TLU), Tongling, Anhui 244000 (China)

    2010-10-15

    A cobalt-free cubic perovskite oxide SrFe{sub 0.9}Sb{sub 0.1}O{sub 3-{delta}} (SFSb) is investigated as a novel cathode for proton-conducting solid oxide fuel cells (H-SOFCs). XRD results show that SFSb cathode is chemically compatible with the electrolyte BaZr{sub 0.1}Ce{sub 0.7}Y{sub 0.1}Yb{sub 0.1}O{sub 3-{delta}} (BZCYYb) for temperatures up to 1000 C. Thin proton-conducting BZCYYb electrolyte and NiO-BaZr{sub 0.1}Ce{sub 0.7}Y{sub 0.1}Yb{sub 0.1}O{sub 3-{delta}} (NiO-BZCYYb) anode functional layer are prepared over porous anode substrates composed of NiO-BZCYYb by a one-step dry-pressing/co-firing process. Laboratory-sized quad-layer cells of NiO-BZCYYb/NiO-BZCYYb/BZCYYb/SFSb are operated from 550 to 700 C with humidified hydrogen ({proportional_to}3% H{sub 2}O) as fuel and the static air as oxidant. An open-circuit potential of 0.996 V, maximum power density of 428 mW cm{sup -2}, and a low electrode polarization resistance of 0.154 {omega} cm{sup 2} are achieved at 700 C. The experimental results indicate that the cobalt-free SFSb is a promising candidate for cathode material for H-SOFCs. (author)

  19. Thermal and Isotopic Anomalies when pd Cathodes are Electrolyzed in Electrolytes Containing Th-Hg Salts Dissolved at Micromolar Concentration in C2H5OD/D2O Mixtures

    Science.gov (United States)

    Celani, F.; Spallone, A.; Righi, E.; Trenta, G.; Catena, C.; D'Agostaro, G.; Quercia, P.; Andreassi, V.; Marini, P.; di Stefano, V.; Nakamura, M.; Mancini, A.; Sona, P. G.; Fontana, F.; Gamberale, L.; Garbelli, D.; Falcioni, F.; Marchesini, M.; Novaro, E.; Mastromatteo, U.

    2005-12-01

    Discussed in this paper is the evolution of work that started by using the M. Fleischmann and S. Pons method and ended by using thin palladium wires electrolyzed in an electrolyte consisting of slightly acidic heavy alcohol-water solution containing thorium (Th) and mercury (Hg) salts at micromolar concentrations. The resulting large and dynamic loading of the Pd wires was studied. The recent use of thorium instead of strontium resulted in thermal anomalies and detection of new elements in larger amounts. The results with Sr are qualitatively in agreement with what was found by Y. Iwamura (Mitsubishi Heavy Industries) using multilayers of Pd-CaO-Pd-Sr in flowing deuterium gas. Most results seem to be in agreement with a "multi-body resonance fusion of deuterons" model recently developed by A.Takahashi (Osaka University).

  20. 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.

  1. 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...

  2. 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....

  3. Analysis of secondary cells with lithium anodes and immobilized fused-salt electrolytes

    Science.gov (United States)

    Cairns, E. J.; Rogers, G. L.; Shimotake, H.

    1969-01-01

    Secondary cells with liquid lithium anodes, liquid bismuth or tellurium cathodes, and fused lithium halide electrolytes immobilized as rigid pastes operate between 380 and 485 degrees. Applications include power sources in space, military vehicle propulsion and special commercial vehicle propulsion.

  4. Determination Of The Aflatoxin B1 In Ground Nut By Differential Pulse Cathodic Stripping Voltammetry (Dpcsv) Technique

    OpenAIRE

    Yaacob, Mohammad Hadzri; Yusoff, Abdull Rahim Hj. Mohd.; Ahamad, Rahmalan

    2009-01-01

    An electro analytical method has been developed for the detection and determination of the 2,3,6a,9a-tetrahydro- 4-methoxycyclo penta[c] furo[3’,2’:4,5] furo [2,3-h][l] benzopyran-1,11-dione (aflatoxin B1, AFB1) by a differential pulse cathodic stripping voltammetry on a hanging mercury drop electrode (HMDE) in aqueous solution with Britton-Robinson buffer (BRb) as supporting electrolyte. Effect of instrumental parameters such as accumulation potential (Eacc), accumulation time (tacc) and ...

  5. LaNi1-xCoxO3-δ (x=0.4 to 0.7) cathodes for solid oxide fuel cells by infiltration

    DEFF Research Database (Denmark)

    Chrzan, Aleksander; Ovtar, Simona; Chen, Ming

    2015-01-01

    Performance of LaNi1-xCoxO3-δ (LNC) (x=0.4 to 0.7) as a cathode in solid oxide fuel cell (SOFC) is evaluated. Symmetrical cathode/electrolyte/cathode cells for electrochemical testing are prepared by infiltration of yttria stabilized zirconia (YSZ) backbone with LNC solutions. It is showed...

  6. Cationic Intermixing and Reactivity at the La2 Mo2 O9 /La0.8 Sr0.2 MnO3-δ Solid Oxide Fuel Cell Electrolyte-Cathode Interface.

    Science.gov (United States)

    Ravella, Uday K; Liu, Jingjing; Corbel, Gwenaël; Skinner, Stephen J; Lacorre, Philippe

    2016-08-23

    Among standard high-temperature cathode materials for solid oxide fuel cells, La0.8 Sr0.2 MnO3-δ (LSM) displays the least reactivity with the oxide-ion conductor La2 Mo2 O9 (LMO), yet a reaction is observed at high processing temperatures, identified by using XRD and focused ion beam secondary-ion mass spectrometry (FIB-SIMS) after annealing at 1050 and 1150 °C. Additionally, Sr and Mn solutions were deposited and annealed on LMO pellets, as well as a Mo solution on a LSM pellet. From these studies several reaction products were identified by using XRD and located by using FIB-SIMS on the surface of pelletised samples. We used depth profiling to show that the reactivity extended up to ∼10 μm from the surface region. If Sr was present, a SrMoO4 -type scheelite phase was always observed as a reaction product, and if Mn was present, LaMnO3+δ single crystals were observed on the surface of the LMO pellets. Additional phases such as La2 MoO6 and La6 MoO12 were also detected depending on the configuration and annealing temperature. Reaction mechanisms and detailed reaction formulae are proposed to explain these observations. The strongest driving force for cationic diffusion appears to originate from Mo(6+) and Mn(3+) cations, rather than from Sr(2+) . PMID:27478975

  7. Electrolytic decontamination of the 3013 inner can

    International Nuclear Information System (INIS)

    Disposition of plutonium recovered from nuclear weapons or production residues must be stored in a manner that ensures safety. The criteria that has been established to assure the safety of stored materials for a minimum of 50 years is DOE-STD-3013. Los Alamos National Laboratory (LANL) has designed a containment package in accordance with the DOE standard. The package consists of an optional convenience (food pack) can, a welded type 304L stainless steel inner (primary) can, and a welded type 304L stainless steel outer (secondary) can. With or without the food pack can, the material is placed inside the primary can and welded shut under a helium atmosphere. This activity takes place totally within the confinement of the glove box line. Following the welding process, the can is checked for leaks and then sent down the line for decontamination. Once decontaminated, the sealed primary can may be removed from the glove box line. Welding of the secondary container takes place outside the glove box line. The highly automated decontamination process that has been developed to support the packaging of Special Nuclear Materials is based on an electrolytic process similar to the wide spread industrial technique of electropolishing. The can is placed within a specially designed stainless steel fixture built within a partition of a glove box. This fixture is then filled with a flowing electrolyte solution. A low DC electric current is made to flow between the can, acting as the anode, and the fixture, acting as the cathode. Following the decontamination, the system provides a flow of rinse water through the fixture to rinse the can of remaining salt residues. The system then carried out a drying cycle. Finally, the fixture is opened from the opposite side of the partition and the can surface monitored directly and through surface smears to assure that decontamination is adequate

  8. 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).

  9. 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.

  10. High-voltage virtual-cathode microwave simulations

    Energy Technology Data Exchange (ETDEWEB)

    Thode, L.; Snell, C.M.

    1991-01-01

    In contrast to a conventional microwave tube, a virtual-cathode device operates above the space-charge limit where the depth of the space-charge potential is sufficiently large to cause electron reflection. The region associated with electron reflection is referred to as a virtual cathode. Microwaves can be generated through oscillations in the position of the virtual cathode and by reflexing electrons trapped in the potential well formed between the real and virtual cathodes. A virtual-cathode device based on the first mechanism is a vircator while one based on latter mechanism is a reflex diode. A large number of low-voltage virtual-cathode microwave configurations have been investigated. Initial simulations of a high-voltage virtual-cathode device using a self-consistent particle-in-cell code indicated reasonable conversion efficiency with no frequency chirping. The nonchirping character of the high-voltage virtual-cathode device lead to the interesting possibility of locking four very-high-power microwave devices together using the four transmission lines available at Aurora. Subsequently, in support of two high-voltage experiments, simulations were used to investigate the effect of field-emission threshold and velvet position on the cathode; anode and cathode shape; anode-cathode gap spacing; output waveguide radius; diode voltage; a cathode-coaxial-cavity resonator; a high-frequency ac-voltage drive; anode foil scattering and energy loss; and ion emission on the microwave frequency and power. Microwave

  11. Chemical compatibility, redox behavior, and electrochemical performance of Nd1−xSrxCoO3−δ cathodes based on Ce1.9Gd0.1O1.95 for intermediate-temperature solid oxide fuel cells

    International Nuclear Information System (INIS)

    Highlights: ► Nd1−xSrxCoO3−δ (x = 0.3, 0.4, 0.5, 0.6, and 0.7) are synthesized by glycine nitrate method and investigated the effect of Sr substitution for Nd. ► Electrical properties of the samples are identified by a four-terminal DC arrangement in air. ► Symmetrical half cells are measured by impedance spectroscopy at 500, 550, 600, 650, and 700 °C in air under an open-circuit condition. ► Electrochemical performances of Nd1−xSrxCoO3−δ cathodes are investigated using an anode supported cell based on GDC electrolyte for application to IT-SOFCs. - Abstract: The effect of Sr substitution for Nd on Nd1−xSrxCoO3−δ (NSC) (x = 0.3, 0.4, 0.5, 0.6, and 0.7) is investigated to evaluate NSC as a cathode material based on Gd0.1Ce0.9O1.95 (GDC) electrolyte for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The NSC powders are prepared by the glycine nitrate method. At a given temperature, the electrical conductivity increases with increasing Sr content up to x = 0.5 and then decreases for x > 0.5. The redox behavior of NSC (x = 0.3, 0.5, and 0.7) cathodes is studied by the coulometric titration at 700 °C. In order to investigate the area specific resistances of NSC–GDC cathodes, symmetrical half cells (cathode/electrolyte/cathode) are measured using impedance spectroscopy at various temperatures in air under open circuit voltage (OCV) condition. The electrochemical performance of NSC–GDC cathodes is measured using an NSC–GDC/GDC/Ni-GDC anode supported cell. The maximum power density of NSC–GDC cathodes increases with increasing strontium content up to x = 0.5 and then decreases at 700 °C. In terms of electrical conductivity and electrochemical performance, Nd1−xSrxCoO3−δ (x = 0.5) is more suitable as a cathode material based on GDC electrolyte in IT-SOFC applications.

  12. Gas evolution in aluminum electrolytic capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Aleixandre, C.; Albella, J.M.; Martinez-Duart, J.M.

    1984-03-01

    Gas evolution in aluminum electrolytic capacitors constitutes one of their main drawbacks in comparison to other types of capacitors lacking a liquid electrolyte. In this respect, one of the most common causes of failure shown by liquid electrolyte capacitors is electrolyte leakage through the seal or even explosions produced by internal pressure buildup. In order to prevent these hazards, some substances, known as depolarizers, are usually added to the capacitor electrolyte with the purpose of absorbing the hydrogen evolved at the cathode (1, 2). Although the gas evolution problem in electrolytic capacitors has been known for a long time, there is a lack of literature on both direct measurements of the gas evolved and assessments of the amount of depolarizer active for the hydrogen absorption process. Aluminum electrolytic capacitors of 100..mu..F and 40V nominal voltage, miniature type (diam 8 mm, height 18.5 mm), were manufactured under standard specifications. The capacitors were filled with about 0.5 ml of an electrolyte consisting essentially of a solution of boric, adipic, and phosphoric acids in ethylene glycol. Picric acid and p-benzoquinone in molar concentrations of 0.01M and 0.05M, respectively, were added as depolarizers, yielding an electrolyte with a resistivity of about 80 ..cap omega..-cm and a pH of 5.1. The pressure inside the capacitors was monitored by a conventional Ushaped manometer made from a capillary glass tube filled with distilled water. The number of mols of gas generated in the capacitor (/eta/ /SUB g/ ) was calculated from the measured pressure (sensitivity 0.1 mm Hg) and the value of the internal volume of the manometercapacitor system.

  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. 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.

  15. 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.

  16. 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

  17. Compatibility of La26O27(BO3)8 electrolyte with

    OpenAIRE

    Kravchyk, K. V.; Quarez, E.; Caldes, M.; Le Gal La Salle, A.; Joubert, O.

    2011-01-01

    The chemical and mechanical compatibility of proton conducting La26O27(BO3)8 (LBO) electrolyte with standard cathode materials LSM, LSCM, La2NiO4 and BSCF was investigated. The results show that LSM, LSCM and La2NiO4 cathodes are chemically and mechanically stable with the LBO electrolyte, and BSCF reacts with LBO after heat-treatment of their mechanical ground mixtures at T=1150°C. Symmetrical cell tests based on LBO demonstrated that the values of the cathode ASR (area specif...

  18. 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...

  19. High performance MCFC using Li/Na electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Donado, R.A.; Ong, E.T.; Sishtla, C.I.

    1995-08-01

    The substitution of a lithium/ sodium carbonate (Li/Na) mixture for the lithium/potassium carbonate (Li/K) electrolyte used in MCFCs holds the promise of higher ionic conductivity, higher exchange current density at both electrodes, lower vapor pressure, and lower cathode dissolution rates. However, when the substitution is made in cells optimized for use with the Li/K electrolyte, the promised increase in performance is not realized. As a consequence the literature contains conflicting data with regard to the performance, compositional stability, and chemical reactivity of the Li/Na electrolyte. Experiments conducted at the Institute of Gas Technology (IGT) concluded that the source of the problem is the different wetting characteristics of the two electrolytes. Electrode pore structures optimized for use with Li/K do not work well with Li/Na. Using proprietary methods and materials, IGT was able to optimize a set of electrodes for the Li/Na electrolyte. Experiments conducted in bench-scale cells have confirmed the superior performance of the Li/Na electrolyte compared to the Li/K electrolyte. The Li/Na cells exhibited a 5 to 8 percent improvement in overall performance, a substantial decrease in the rate of cathode dissolution, and a decreased decay rate. The longest running cell has logged over 13,000 hours of operation with a decay rate of less than 2 mV/1000 hours.

  20. Li-air batteries having ether-based electrolytes

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-03-03

    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.

  1. Lithium air batteries having ether-based electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. Molybdenum sulfide nanosheet arrays supported on Ti plate: an efficient hydrogen-evolving cathode over the whole pH range

    International Nuclear Information System (INIS)

    Electrochemical water splitting offers a simple route to make hydrogen and it is of great importance but still remains a big challenge to develop cost-effective electrocatalysts for catalyzing the hydrogen evolution reaction over the whole pH range. In this work, molybdenum sulfide nanosheet arrays are hydrothermally grown on Ti plate as an integrated 3D hydrogen-evolving cathode. This electrode exhibits high catalytic activity in acidic media, displaying 10 and 100 mA cm−2 at overpotentials of 108 and 205 mV, respectively, and it operates stably within 55 h of operation. Moreover, this electrode is also capable of efficiently catalyzing the HER under neutral and strongly basic conditions

  3. 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...

  4. 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

  5. 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

  6. Scanning optical pyrometer for measuring temperatures in hollow cathodes

    OpenAIRE

    Polk, J. E.; Marrese-Reading, C. M.; Thornber, B.; Dang, L.; Johnson, L. K.; Katz, I

    2007-01-01

    Life-limiting processes in hollow cathodes are determined largely by the temperature of the electron emitter. To support cathode life assessment, a noncontact temperature measurement technique which employs a stepper motor-driven fiber optic probe was developed. The probe is driven inside the hollow cathode and collects light radiated by the hot interior surface of the emitter. Ratio pyrometry is used to determine the axial temperature profile. Thermocouples on the orifice plate provide measu...

  7. Electrochemical characterization of La0.6Ca0.4Fe0.8Ni0.2O3-δ perovskite cathode for IT-SOFC

    DEFF Research Database (Denmark)

    Ortiz-Vitoriano, N.; Hauch, Anne; Ruiz De Larramendi, I.;

    2013-01-01

    Electrolyte supported symmetric cells featuring La0.6Ca 0.4Fe0.8Ni0.2O3 (LCFN) electrodes are studied by electrochemical impedance spectroscopy. The aim is to describe the polarization losses of this mixed ionic electronic conductor electrode at various cell operating conditions for cells sintered...... at different temperatures. An equivalent circuit describing the cathode polarization resistances was constructed from analyzing impedance spectra recorded at different oxygen partial pressures and temperatures. Favorable oxygen reduction reaction properties are demonstrated for the LCFN cell sintered at 750 C...

  8. 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.

  9. Dynamic Aspects of Solid Solution Cathodes for Electrochemical Power Sources

    DEFF Research Database (Denmark)

    Atlung, Sven; West, Keld; Jacobsen, Torben

    1979-01-01

    , in particularfor vehicle propulsion, and electrochemical and constructional factors. It isargued that the energy obtainable at a given load is limited by saturation ofthe surface layers of cathode particles with cations, and that the time beforesaturation occurs is determined by diffusion of cations and electrons......–10 cm2 sec–1. On the basis of an approximaterelation between cathode thickness and electrode spacing the specificenergy for the Li/TiS2 system with organic electrolyte is estimated to be 120–150W-hr/kg in agreement with published values. ©1979 The Electrochemical Society, Inc....

  10. 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 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...... for batteries with 1000 ppm water added- to the electrolyte in comparison to dry batteries, indicating additional parasitic electrochemical or chemical processes. A comparable capacity of the wet and dry batteries indicates that the reaction mechanism in the Li-O2 battery also depends on the 'surface...

  11. Improved Cyclability of Liquid Electrolyte Lithium/Sulfur Batteries by Optimizing Electrolyte/Sulfur Ratio

    Directory of Open Access Journals (Sweden)

    Sheng S. Zhang

    2012-12-01

    Full Text Available A liquid electrolyte lithium/sulfur (Li/S cell is a liquid electrochemical system. In discharge, sulfur is first reduced to highly soluble Li2S8, which dissolves into the organic electrolyte and serves as the liquid cathode. In solution, lithium polysulfide (PS undergoes a series of complicated disproportionations, whose chemical equilibriums vary with the PS concentration and affect the cell’s performance. Since the PS concentration relates to a certain electrolyte/sulfur (E/S ratio, there is an optimized E/S ratio for the cyclability of each Li/S cell system. In this work, we study the optimized E/S ratio by measuring the cycling performance of Li/S cells, and propose an empirical method for determination of the optimized E/S ratio. By employing an electrolyte of 0.25 m LiSO3CF3-0.25 m LiNO3 dissolved in a 1:1 (wt:wt mixture of dimethyl ether (DME and 1,3-dioxolane (DOL in an optimized E/S ratio, we show that the Li/S cell with a cathode containing 72% sulfur and 2 mg cm−2 sulfur loading is able to retain a specific capacity of 780 mAh g−1 after 100 cycles at 0.5 mA cm−2 between 1.7 V and 2.8 V.

  12. The dependence of vircator oscillation mode on cathode material

    Science.gov (United States)

    Li, Limin; Liu, Lie; Cheng, Guoxin; Xu, Qifu; Wan, Hong; Chang, Lei; Wen, Jianchun

    2009-06-01

    This paper presents the effects of cathode materials on the oscillation mode of a virtual cathode oscillator (vircator). In the case of the stainless steel cathode, an oscillation mode hopping appeared with two separate frequencies. Interestingly, the vircator using the carbon fiber cathode exhibited an almost unchanged microwave frequency throughout the microwave pulse. To understand this phenomenon, several parameters are compared, including the diode voltage, accelerating gap, emitting area, and beam uniformity. It was found that a flat-top voltage and a relatively stable gap will provide a possibility of generating a constant microwave frequency. Further, the cathode operated in a regime where the beam current was between the space-charge limited current determined by Child-Langmuir law and the bipolar flow. On the cathode surface, the electron emission is initiated from discrete plasma spots and next from a continuing area, while there is a liberation process of multilayer gases on the anode surface. The changes in the emitting area of carbon fiber cathode showed a self-quenching process, which is not observed in the case of stainless steel cathode. The two-dimensional effect of microwave frequency is introduced, and the obtained results supported the experimental observations on the oscillation mode. By examining the cross section of electron beam, the electron beam for carbon fiber cathode was significantly centralized, while the discrete beam spots appeared for stainless steel cathode. These results show that the slowed diode closure, high emission uniformity, and stable microwave frequency tend to be closely tied.

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

    Energy Technology Data Exchange (ETDEWEB)

    Fabbri, Emiliana; Bi, Lei; Pergolesi, Daniele; Traversa, Enrico [International Research Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

    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. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. Electrolytic production of uranous nitrate

    International Nuclear Information System (INIS)

    Efficient production of uranous nitrate is important in nuclear fuel reprocessing because U(IV) acts as a plutonium reductant in solvent extraction and can be coprecipitated with plutonium and/or throium as oxalates during fuel reprocessing. Experimental conditions are described for the efficient electrolytic production of uranous nitrate for use as a reductant in the SRP Purex process. The bench-scale, continuous-flow, electrolysis cell exhibits a current efficiency approaching 100% in combination with high conversion rates of U(VI) to U(IV) in simulated and actual SRP Purex solutions. High current efficiency is achieved with a voltage-controlled mercury-plated platinum electrode and the use of hydrazine as a nitrite scavenger. Conversion of U(VI) to U(IV) proceeds at 100% efficiency. Cathodic gas generation is minimal. The low rate of gas generation permits a long residence time within the cathode, a necessary condition for high conversions on a continuous basis. Design proposals are given for a plant-scale, continuous-flow unit to meet SRP production requirements. Results from the bench-scale tests indicate that an 8-kW unit can supply sufficient uranous nitrate reductant to meet the needs of the Purex process at SRP

  15. Solid polymer electrolyte water electrolysis

    Science.gov (United States)

    Takenaka, H.; Torikai, E.; Kawami, Y.; Wakabayashi, N.

    Electrocatalyst performances and bonding to solid polymer electrolytes used for water electrolysis are investigated. Noble metal and metal alloy catalysts were plated to Nafion perfluorosulfonic acid polymer membranes without a binder by the use of a reducing agent solution held on the opposite side of the membrane from a metal salt solution. It was found that pretreatment of the membrane by hydrothermal treatment or gas plasma surface roughening improves metal adhesivity and thus reduces contact resistance between the membrane and the catalyst. Measurements of the constituents of cell voltage for platinum, rhodium and iridium anodes with platinum cathodes reveals that anodic overvoltage is a major component of voltage loss and depends on the type of electrocatalyst, being greatest for Pd and least for Ir. Ir and Ir-alloy electrodes, which were found to be the best catalysts for oxygen evolution, are found to have Tafel slopes of 0.04-0.06 V/decade. In a cell with a Pt cathode and Ir anode, cell voltage is observed to decrease with increasing temperature, reaching 1.56-1.59 V at a current density of 50 A/sq dm and 90 C, which corresponds to a thermal efficiency of 93-95%.

  16. Electrolytic method to make alkali alcoholates using ion conducting alkali electrolyte/separator

    Science.gov (United States)

    Joshi, Ashok V.; Balagopal, Shekar; Pendelton, Justin

    2011-12-13

    Alkali alcoholates, also called alkali alkoxides, are produced from alkali metal salt solutions and alcohol using a three-compartment electrolytic cell. The electrolytic cell includes an anolyte compartment configured with an anode, a buffer compartment, and a catholyte compartment configured with a cathode. An alkali ion conducting solid electrolyte configured to selectively transport alkali ions is positioned between the anolyte compartment and the buffer compartment. An alkali ion permeable separator is positioned between the buffer compartment and the catholyte compartment. The catholyte solution may include an alkali alcoholate and alcohol. The anolyte solution may include at least one alkali salt. The buffer compartment solution may include a soluble alkali salt and an alkali alcoholate in alcohol.

  17. Is alpha-V2O5 a cathode material for Mg insertion batteries?

    Science.gov (United States)

    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 α-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 α-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 α-V2O5.

  18. 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.

  19. Scanning optical pyrometer for measuring temperatures in hollow cathodes

    International Nuclear Information System (INIS)

    Life-limiting processes in hollow cathodes are determined largely by the temperature of the electron emitter. To support cathode life assessment, a noncontact temperature measurement technique which employs a stepper motor-driven fiber optic probe was developed. The probe is driven inside the hollow cathode and collects light radiated by the hot interior surface of the emitter. Ratio pyrometry is used to determine the axial temperature profile. Thermocouples on the orifice plate provide measurements of the external temperature during cathode operation and are used to calibrate the pyrometer system in situ with a small oven enclosing the externally heated cathode. The diagnostic method and initial measurements of the temperature distribution in a hollow cathode are discussed

  20. 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...... that these nanoparticulate infiltrates have good oxygen reduction capabilities. The significance of the choice of ionic conducting backbone was also addressed by replacing the CGO with Bi2V0.9Cu0.1O5.35 (BICUVOX). Cathodes with a BICUVOX backbone exhibit performance degradation not observed in LSC infiltrated - CGO cathodes...

  1. A new method to control electrolytes pH by circulation system in electrokinetic soil remediation.

    Science.gov (United States)

    Lee, H H; Yang, J W

    2000-10-01

    To simultaneously avoid a decrease of electro-osmotic flow by hydrogen ions and to increase heavy metal precipitation due to hydroxide ions, simulated electrokinetic remediation was conducted in saturated kaolinite specimens loaded with lead(II) using an electrolyte circulation method to control electrolyte pH. At an electrolyte circulation rate of 1.1 ml/min, it was possible to increase the anolyte pH from 2 to 4 and decrease the catholyte pH from 12 to 8. Using electrolyte circulation, it was observed that the rate of decrease of clay pH due to the change of electrolyte pH was reduced. As a result, the operable period was extended and the removal efficiency for lead(II) was also increased. It was observed that most of the effluent lead(II) from the cathode compartment was electroplated onto the cathode and that residual effluent lead(II) did not precipitate onto, or adsorb to, the clay at the anode compartment during circulation. Therefore, there was no need to treat the electrolyte because there was virtually no effluent from the cathode compartment in the circulation system. It was also found that the electrolyte volume required to sustain the electrolytic reaction was sufficient for the whole electrokinetic remediation process. PMID:10946130

  2. Deciphering the thermal behavior of lithium rich cathode material by in situ X-ray diffraction technique

    Science.gov (United States)

    Muhammad, Shoaib; Lee, Sangwoo; Kim, Hyunchul; Yoon, Jeongbae; Jang, Donghyuk; Yoon, Jaegu; Park, Jin-Hwan; Yoon, Won-Sub

    2015-07-01

    Thermal stability is one of the critical requirements for commercial operation of high energy lithium-ion batteries. In this study, we use in situ X-ray diffraction technique to elucidate the thermal degradation mechanism of 0.5Li2MnO3-0.5LiNi0.33Co0.33Mn0.33O2 lithium rich cathode material in the absence and presence of electrolyte to simulate the real life battery conditions and compare its thermal behavior with the commercial LiNi0.33Co0.33Mn0.33O2 cathode material. We show that the thermal induced phase transformations in delithiated lithium rich cathode material are much more intense compared to similar single phase layered cathode material in the presence of electrolyte. The structural changes in both cathode materials with the temperature rise follow different trends in the absence and presence of electrolyte between 25 and 600 °C. Phase transitions are comparatively simple in the absence of electrolyte, the fully charged lithium rich cathode material demonstrates better thermal stability by maintaining its phase till 379 °C, and afterwards spinel structure is formed. In the presence of electrolyte, however, the spinel structure appears at 207 °C, subsequently it transforms to rock salt type cubic phase at 425 °C with additional metallic, metal fluoride, and metal carbonate phases.

  3. Molten salt electrolyte separator

    Science.gov (United States)

    Kaun, Thomas D.

    1996-01-01

    A molten salt electrolyte/separator for battery and related electrochemical systems including a molten electrolyte composition and an electrically insulating solid salt dispersed therein, to provide improved performance at higher current densities and alternate designs through ease of fabrication.

  4. Cathodes - Technological review

    Energy Technology Data Exchange (ETDEWEB)

    Cherkouk, Charaf; Nestler, Tina [Institut für Experimentelle Physik, Technische Universität Bergakademie Freiberg, Leipziger Straße 23, 09596 Freiberg (Germany)

    2014-06-16

    Lithium cobalt oxide (LiCoO{sub 2}) was already used in the first commercialized Li-ion battery by SONY in 1990. Still, it is the most frequently used cathode material nowadays. However, LiCoO{sub 2} is intrinsically unstable in the charged state, especially at elevated temperatures and in the overcharged state causing volume changes and transport limitation for high power batteries. In this paper, some technological aspects with large impact on cell performance from the cathode material point of view will be reviewed. At first it will be focused on the degradation processes and life-time mechanisms of the cathode material LiCoO{sub 2}. Electrochemical and structural results on commercial Li-ion batteries recorded during the cycling will be discussed. Thereafter, advanced nanomaterials for new cathode materials will be presented.

  5. 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.

  6. Cathodes - Technological review

    International Nuclear Information System (INIS)

    Lithium cobalt oxide (LiCoO2) was already used in the first commercialized Li-ion battery by SONY in 1990. Still, it is the most frequently used cathode material nowadays. However, LiCoO2 is intrinsically unstable in the charged state, especially at elevated temperatures and in the overcharged state causing volume changes and transport limitation for high power batteries. In this paper, some technological aspects with large impact on cell performance from the cathode material point of view will be reviewed. At first it will be focused on the degradation processes and life-time mechanisms of the cathode material LiCoO2. Electrochemical and structural results on commercial Li-ion batteries recorded during the cycling will be discussed. Thereafter, advanced nanomaterials for new cathode materials will be presented

  7. Aqueous cathode for next-generation alkali-ion batteries.

    Science.gov (United States)

    Lu, Yuhao; Goodenough, John B; Kim, Youngsik

    2011-04-20

    The lithium-ion batteries that ushered in the wireless revolution rely on electrode strategies that are being stretched to power electric vehicles. Low-cost, safe electrical-energy storage that enables better use of alternative energy sources (e.g., wind, solar, and nuclear) requires an alternative strategy. We report a demonstration of the feasibility of a battery having a thin, solid alkali-ion electrolyte separating a water-soluble redox couple as the cathode and lithium or sodium in a nonaqueous electrolyte as the anode. The cell operates without a catalyst and has high storage efficiency. The possibility of a flow-through mode for the cathode allows flexibility of the cell design for safe, large-capacity electrical-energy storage at an acceptable cost. PMID:21443190

  8. Effect of cathode separator structure on performance characteristics of free-breathing PEMFCs

    OpenAIRE

    Tabe, Yutaka; Park, Sang-Kyun; Kikuta, Kazushige; Chikahisa, Takemi; Hishinuma, Yukio

    2006-01-01

    The performance of free-breathing polymer electrolyte membrane fuel cells (PEMFCs) was studied experimentally and the effect of the cathode separator structure on the cell performance was investigated. Two types of cathode separators were used for a cell with an 18 cm2 active area: an open type with parallel rectangular open-slits and a channel type with straight vertical channels with open ends. The polarization curves, cell impedance, and contact pressure distribution of the separators were...

  9. Preparation, characterization and degradation investigations of cathode catalysts for automotive PEM fuel cells systems

    OpenAIRE

    Marcu, Alina

    2014-01-01

    This research was designed to meet Daimler systematic efforts to address future electromobility demands. The work focuses on developing potential cathode catalysts and tests procedures to be employed in prototype fuel cells. In order to achieve commercial cost-competitive polymer electrolyte membrane fuel cells (PEM FC), the following major challenges have to be addressed: i) The catalytic mass activity of the cathode catalysts has to be at least 0.44 A/mg Pt representing an increased factor ...

  10. 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...

  11. 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...

  12. 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.

  13. Nanoporous polymer electrolyte

    Science.gov (United States)

    Elliott, Brian; Nguyen, Vinh

    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.

  14. 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.

  15. Composite Solid Electrolyte for Li Battery Applications

    Science.gov (United States)

    Nagasubramanian, G.; Attia, A. I.; Halpert, G.; Peled, E.

    1993-01-01

    The electrochemical, bulk and interfacial properties of the polyethylene oxide (PEO) based composite solid electrolyte (CSE) comprising LiI, PEO, and Al2O3 have been evaluated for Li battery applications. The bulk interfacial and transport properties of the CSEs seem to strongly depend on the alumina particle size. For the CSE films with 0.05 micron alumina while the bulk conductivity is around 10(exp -4) (mho/cm) at 103 C, the Li ion transport number seems to be close to unity at the same temperature. Compared to the PEO electrolyte this polymer composite electrolyte seems to exhibit robust mechanical and interfacial properties. We have studied three different films with three different alumina sizes in the range 0.01-0.3 micron. Effects of Al2O3 particle size on the electrochemical performance of polymer composite electrolyte is discussed. With TiS2 as cathode a 10 mAh small capacity cell was charged and discharged at C/40 and C/20 rates respectively.

  16. In situ growth of polymer electrolytes on lithium ion electrode surfaces

    Energy Technology Data Exchange (ETDEWEB)

    El-Enany, Gaber; Lacey, Matthew J.; Johns, Phil A.; Owen, John R. [School of Chemistry, University of Southampton, SO17 1BJ Southampton, Hants (United Kingdom)

    2009-12-15

    Polyacrylonitrile (PAN) films were grown on glassy carbon, nickel foam and MnO{sub 2} substrates by cathodic electropolymerisation of acrylonitrile in acetonitrile with tetrabutylammonium perchlorate (TBAP) as the supporting electrolyte. The electronic barrier properties of the films were confirmed by impedance spectroscopy of carbon vertical stroke PAN vertical stroke Hg cells while the ionic resistance of the films varied from 200 k{omega} cm{sup 2} in the dry state to 1.4 {omega} cm{sup 2} when plasticised with 1 M LiPF{sub 6} in propylene carbonate. A galvanic cell was prepared by successive electrodepositions of MnO{sub 2} and PAN on a carbon substrate, using liquid lithium amalgam as the top contact. The cell showed a stable open circuit potential and behaved normally under the galvanostatic intermittent titration technique (GITT). (author)

  17. In situ X-ray studies of film cathodes for solid oxide fuel cells

    International Nuclear Information System (INIS)

    Highlights: •Synchrotron X-rays are used to study in operando the structural and chemical changes of LSM and LSCF film cathodes during half-cell operations. •A-site and B-site cations actively segregate or desegregate on the changes of temperature, pO2, and electrochemical potential. •Chemical lattice expansions show that oxygen-cathode interface is the primary source of rate-limiting processes. •The surface and subsurface of the LSM and LSCF films have different oxidation-states due to vacancy concentration changes. •Liquid-phase infiltration and coarsening processes of cathode materials into porous YSZ electrolyte backbone were monitored by USAXS. -- Abstract: Synchrotron-based X-ray techniques have been used to study in situ the structural and chemical changes of film cathodes during half-cell operations. The X-ray techniques used include X-ray reflectivity (XR), total-reflection X-ray fluorescence (TXRF), high-resolution diffraction (HRD), ultra-small angle X-ray scattering (USAXS). The epitaxial thin film model cathodes for XR, TXRF, and HRD measurements are made by pulse laser deposition and porous film cathodes for USAX measurements are made by screen printing technique. The experimental results reviewed here include A-site and B-site segregations, lattice expansion, oxidation-state changes during cell operations and liquid-phase infiltration and coarsening of cathode to electrolyte backbone

  18. 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...

  19. Durability and performance optimization of cathode materials for fuel cells

    Science.gov (United States)

    Colon-Mercado, Hector Rafael

    The primary objective of this dissertation is to develop an accelerated durability test (ADT) for the evaluation of cathode materials for fuel cells. The work has been divided in two main categories, namely high temperature fuel cells with emphasis on the Molten Carbonate Fuel Cell (MCFC) cathode current collector corrosion problems and low temperature fuel cells in particular Polymer Electrolyte Fuel Cell (PEMFC) cathode catalyst corrosion. The high operating temperature of MCFC has given it benefits over other fuel cells. These include higher efficiencies (>50%), faster electrode kinetics, etc. At 650°C, the theoretical open circuit voltage is established, providing low electrode overpotentials without requiring any noble metal catalysts and permitting high electrochemical efficiency. The waste heat is generated at sufficiently high temperatures to make it useful as a co-product. However, in order to commercialize the MCFC, a lifetime of 40,000 hours of operation must be achieved. The major limiting factor in the MCFC is the corrosion of cathode materials, which include cathode electrode and cathode current collector. In the first part of this dissertation the corrosion characteristics of bare, heat-treated and cobalt coated titanium alloys were studied using an ADT and compared with that of state of the art current collector material, SS 316. PEMFCs are the best choice for a wide range of portable, stationary and automotive applications because of their high power density and relatively low-temperature operation. However, a major impediment in the commercialization of the fuel cell technology is the cost involved due to the large amount of platinum electrocatalyst used in the cathode catalyst. In an effort to increase the power and decrease the cathode cost in polymer electrolyte fuel cell (PEMFC) systems, Pt-alloy catalysts were developed to increase its activity and stability. Extensive research has been conducted in the area of new alloy development and

  20. 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.

  1. Hydrodynamic Reaction Model of a Spouted Bed Electrolytic Reactor

    Science.gov (United States)

    Alireza Shirvanian, Pezhman; Calo, Joseph

    2002-08-01

    An Eulerian model is presented that has been developed to describe the hydrodynamics, mass transfer, and metal ion reduction mass transfer in a cylindrical, spouted bed electrolytic reactor. Appropriate boundary conditions are derived from kinetic theory and reaction kinetics for the hydrodynamics and mass transfer and reaction on the cathodic conical bottom of the reactor, respectively. This study was undertaken as a part of a project focused on the development of a Spouted Bed Electrolytic Reactor (SBER) for metals recovery. The results presented here include the effect of particle loading, inlet jet velocity, Solution pH, and temperature on void fraction distribution, pressure drop, particles recirculation rate, and metal recovery rate.

  2. 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...

  3. 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...

  4. Cycling of lithium/metal oxide cells using composite electrolytes containing fumed silicas

    International Nuclear Information System (INIS)

    The effect on cycle capacity is reported of cathode material (metal oxide, carbon, and current collector) in lithium/metal oxide cells cycled with fumed silica-based composite electrolytes. Three types of electrolytes are compared: filler-free electrolyte consisting of methyl-terminated poly(ethylene glycol) oligomer (PEGdm, Mw=250)+lithium bis(trifluromethylsufonyl)imide (LiTFSI) (Li:O=1:20), and two composite systems of the above baseline liquid electrolyte containing 10-wt% A200 (hydrophilic fumed silica) or R805 (hydrophobic fumed silica with octyl surface group). The composite electrolytes are solid-like gels. Three cathode active materials (LiCoO2, V6O13, and LixMnO2), four conducting carbons (graphite Timrex [reg] SFG 15, SFG 44, carbon black Vulcan XC72R, and Ketjenblack EC-600JD), and three current collector materials (Al, Ni, and carbon fiber) were studied. Cells with composite electrolytes show higher capacity, reduced capacity fade, and less cell polarization than those with filler-free electrolyte. Among the three active materials studied, V6O13 cathodes deliver the highest capacity and LixMnO2 cathodes render the best capacity retention. Discharge capacity of Li/LiCoO2 cells is affected greatly by cathode carbon type, and the capacity decreases in the order of Ketjenblack>SFG 15>SFG 44>Vulcan. Current collector material also plays a significant role in cell cycling performance. Lithium/vanadium oxide (V6O13) cells deliver increased capacity using Ni foil and carbon fiber current collectors in comparison to an Al foil current collector

  5. Optimization of Ferritic Steel Porous Supports for Protonic Fuel Cells Working at 600°C

    DEFF Research Database (Denmark)

    Venkatachalam, Vinothini; Molin, Sebastian; Chen, Ming;

    2014-01-01

    is particularly helpful for a porous metal supported cell because it limits the corrosion of the metal by exposure to water vapor in the anode gas. In this work, we show the effect of composition and microstructure on the high temperature corrosion and phase stability (formation of sigma phase......Metal supported protonic fuel cells (PCFC) offer one major advantage over standard solid oxide fuel cells (SOFC) with oxygen conducting electrolytes, namely that the product, water, is produced on the cathode (air) side. This feature simplifies the engineering of the stack, boosts efficiency, and...... are very promising materials for cost effective protonic fuel cells operating at 600°C....

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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)

  11. Stable artificial solid electrolyte interfaces for lithium batteries

    OpenAIRE

    Ma, Lin; Kim, Mun Sek; Archer, Lynden A.

    2016-01-01

    A rechargeable lithium metal battery (LMB), which uses metallic lithium at the anode, is among the most promising technologies for next generation electrochemical energy storage devices due to its high energy density, particularly when Li is paired with energetic conversion cathodes such as sulfur, oxygen/air, and carbon dioxide. Practical LMBs in any of these designs remain elusive due to multiple stubborn problems, including parasitic reactions of Li metal with liquid electrolytes, unstable...

  12. Hybrid electrolytes with controlled network structures for lithium metal batteries.

    Science.gov (United States)

    Pan, Qiwei; Smith, Derrick M; Qi, Hao; Wang, Shijun; Li, Christopher Y

    2015-10-21

    Solid polymer electrolytes (SPEs) with tunable network structures are prepared by a facile one-pot reaction of polyhedral oligomeric silsesquioxane and poly(ethylene glycol). These SPEs, with high conductivity and high modulus, exhibit superior resistance to lithium dendrite growth even at high current densities. Measurements of lithium metal batteries with a LiFePO4 cathode show excellent cycling stability and rate capability. PMID:26316140

  13. Solid electrolyte interphase in semi-solid flow batteries: a wolf in sheep's clothing.

    Science.gov (United States)

    Ventosa, E; Zampardi, G; Flox, C; La Mantia, F; Schuhmann, W; Morante, J R

    2015-10-18

    The formation of the alkyl carbonate-derived solid electrolyte interphase (SEI) enables the use of active materials operating at very cathodic potentials in Li-ion batteries. However, the SEI in semi-solid flow batteries results in a hindered electron transfer between a fluid electrode and the current collector restricting the operating potentials to ca. 0.8 V vs. Li/Li(+) for EC-based electrolytes. PMID:26242756

  14. 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.

  15. Evaluation of porous ceramic cathode layers for solid oxide fuel cells

    NARCIS (Netherlands)

    Haart, de L.G.J.; Vries, de K.J.; Carvalho, A.P.M.; Frade, J.R.; Marques, F.M.B.

    1991-01-01

    Sr0.15La0.85MnO3 layers with 2 and 10 u thickness, deposited on zirconia based electrolytes, were evaluated as cathodes for high temperature applications. Different electrode layers were characterized in terms of thickness, porosity, three phase boundary line per unit area (TPBL), and concentration

  16. Doped carbon-sulfur species nanocomposite cathode for Li--S batteries

    Science.gov (United States)

    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.

  17. Cathodic processes in the electrochemical synthesis of niobium borides in chloride-fluoride melts

    International Nuclear Information System (INIS)

    Cathodic processes in the electrochemical synthesis of niobium borides are studied. The possibility of electrochemical synthesis of the niobium boride coatings in the kinetic regime is indicated. The electrolyte composition is selected the process parameters which make it possible to obtain both crystal and roentgenoamorphous niobium boride coatings 20-30 μm thick are determined

  18. Pipeline integrity through cathodic protection

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, N. [Gas Authority India Ltd., New Delhi (India); Khanna, A.S. [Indian Inst. of Technology, Bombay (India)

    2008-07-01

    Pipeline integrity management is defined as a process for assessing and mitigating pipeline risks in an effort to reduce both the likelihood and consequences of incidents. Defects on pipelines result in production losses, environmental losses, as well as loss of goodwill and subsequent financial losses. This presentation addressed pipeline integrity through cathodic protection. It noted that pipeline integrity can be strengthened by successfully controlling, monitoring and mitigating corrosion strategies. It can also be achieved by avoiding external and internal corrosion failures. A good coating offers the advantages of low current density; lower power consumption; low wear of anodes; larger spacing between cathodic protection stations; and minimization of interference problems. The presentation reviewed cathodic protection of cross-country pipelines; a sacrificial cathodic protection system; and an impressed current cathodic protection system. The efficiency of a cathodic system was shown to depend on the use of reliable power sources; proper protection criterion; efficient and effective monitoring of cathodic protection; proper maintenance of the cathodic protection system; and effective remedial measures. Selection criteria, power sources, and a comparison of cathodic protection sources were also presented. Last, the presentation addressed protection criteria; current interruption circuits; monitoring of the cathodic protection system; use of corrosion coupons; advantages of weightless coupons; checking the insulating flanges for shorted bolts; insulated/short casings; anodic and cathodic interference; common corridor problems; and intelligent pigging. tabs., figs.

  19. An investigation of functionalized electrolyte using succinonitrile additive for high voltage lithium-ion batteries

    Science.gov (United States)

    Chen, Renjie; Liu, Fan; Chen, Yan; Ye, Yusheng; Huang, Yongxin; Wu, Feng; Li, Li

    2016-02-01

    Succinonitrile (SN) has been used as functional additive to improve the thermal stability and broaden the oxidation electrochemical window of commercial electrolyte 1 M LiPF6/EC/DEC (1:1, by volume) for high-voltage LIBs (cathode: Li1.2Ni0.2Mn0.6O2, anode: Li). 1 wt % SN-based electrolyte showed a wide electrochemical oxidation window of 5.4 V vs Li+/Li and excellent thermal stability demonstrated by thermogravimetry (TG) and X-ray photoelectron spectroscopy (XPS), as well as theoretical analysis according to molecular orbital theory. The LNMO (Li1.2Ni0.2Mn0.6O2) battery with 1 wt % SN-based electrolyte showed better cyclability and capacity retention when charged to higher cut-off voltage. The improved battery performance is mainly attributed to the formation of uniform cathode electrolyte interface (CEI) formed by interfacial reactions between the LNMO cathode and electrolyte. The outcome of this work and the continuous research on this subject can generate critical knowledge for designing thermal stability electrolytes for large format lithium-ion batteries.

  20. 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.

  1. Investigation on polyethylene-supported and nano-SiO2 doped poly(methyl methacrylate-co-butyl acrylate) based gel polymer electrolyte for high voltage lithium ion battery

    International Nuclear Information System (INIS)

    Highlights: • P(MMA-co-BA)/nano-SiO2/PE based GPE was developed for high voltage lithium ion battery. • P(MMA-co-BA)/nano-SiO2/PE has uniform and interconnected pore structure. • The GPE exhibits improved ionic conductivity and compatibility with electrodes. • 5 V battery using the GPE presents excellent cyclic stability. - Abstract: Nano-SiO2 as dopant was used for preparing polyethylene-supported poly(methyl methacrylate-co-butyl acrylate) (P(MMA-co-BA)/PE) based membrane and corresponding gel polymer electrolyte (GPE), which is applied to improve the cyclic stability of high voltage lithium ion battery. P(MMA-co-BA)/nano-SiO2/PE based membranes and corresponding GPEs were characterized with scanning electron spectroscopy, X-ray diffraction, electrochemical impedance spectroscopy, mechanical test, thermogravimetric analysis, linear sweep voltammetry, and charge/discharge test. It is found that the GPE with 5 wt.% nano-SiO2 shows the best performance. Compared to the undoped membrane, the 5 wt.% nano-SiO2 doped membrane has a better pore structure and higher electrolyte uptake, leading to the enhancement in ionic conductivity of the resulting GPE from 1.23 × 10−3 to 2.26 × 10−3 S.cm−1 at room temperature. Furthermore, the thermal stability of the doped membrane is increased from 300 to 320 °C while its decomposition potential of GPE is from 5.0 to 5.6 V (vs. Li/Li+). The cyclic stability of Li/GPE/Li(Li0.13Ni0.30Mn0.57)O2 cell at the high voltage range of 3.5 V ∼ 5.0 V is consequently improved, the capacity retention of the cell using the doped membrane is 92.8% after 50 cycles while only 88.9% for the cell using undoped membrane and 66.9% for the cell using liquid electrolyte

  2. 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.

  3. 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...

  4. SOFC Cathode Mechanisms

    DEFF Research Database (Denmark)

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

    1996-01-01

    litterature. It is argued that this kind of mechanism can only partly explain the experimental observations. The capacitive part of the low frequency response at anodic potentials is shown to be due to gas enclosures at the lectrode-electrolyte interface. As to the inductive activation mechanism of the...

  5. Enhanced Methanol Tolerance of Highly Pd rich Pd-Pt Cathode Electrocatalysts in Direct Methanol Fuel Cells

    International Nuclear Information System (INIS)

    Methanol crossover critically restricts the practical application of direct methanol fuel cells (DMFCs). To resolve this crucial difficulty from the standpoint of electrocatalysis, an electrode material having high activity for the oxygen reduction reaction and low activity for the methanol oxidation reaction compared to widely used Pt-based electrodes is needed for DMFC cathodes. In this research carbon-supported Pd-rich Pd–Pt bimetallic nanoparticle electrocatalysts with 60 wt.% metal content were prepared for this purpose by sodium borohydride reduction of metal chlorides. The physical features of the prepared nanoparticles were investigated by transmission electron microscopy, energy dispersive X-ray spectroscopy, atomic absorption spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and X-ray absorption near edge spectroscopy. Methanol tolerance was tested by means of rotating disk electrode (RDE) voltammetry using oxygen-saturated methanol-containing electrolyte solutions as the anode fuel for DMFC unit cell performance tests. In the RDE measurements, Pd-rich electrocatalysts (carbon-supported Pd19Pt1 nanoparticles) showed excellent methanol tolerance compared with Pd-free Pt electrocatalyst. When Pd19Pt1 nanoparticles were used as a DMFC cathode catalyst, unit cell performance tests showed that the i-V curves of the Pd19Pt1 electrocatalyst decreased slightly with increasing methanol concentration, while that of the Pt electrocatalyst decreased rapidly. The results in a liquid-feed DMFC unit cell test were in good agreement with the methanol tolerant characteristics identified in the RDE measurements

  6. Analysis of electrolyte level change in a lithium air battery

    Science.gov (United States)

    Huang, Jing; Faghri, Amir

    2016-03-01

    A two-dimensional physical model that employs the deformed mesh method to track the electrolyte level in a Li-air coin cell battery is presented and used to investigate the effects of electrolyte level drop during cell discharge. The electrolyte level drop is caused by solid phase volume decrease and electrolyte solvent evaporation. Simulation results show that by neglecting the drop in electrolyte level, a Li-air battery model would under-estimate cell discharge capacity by as much as 22.5% in the parameter range studied. This counter-intuitive result is explained by an in-depth analysis of simulation results. A more realistic prediction of Li2O2 deposit distribution is obtained, with the peak value of Li2O2 volume fraction in the middle of the cathode instead of on the top surface, as predicted by previous studies. The interaction between the battery and its surroundings is considered by incorporating the air chamber into the computation domain. The diffusion of solvent vapor and oxygen in this chamber is included. For batteries using volatile solvents such as DMF, increasing the air chamber radius from 5 cm to 15 cm would result in a 72% increase of discharge capacity at the cost of losing a large amount of electrolyte.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Low temperature solid oxide fuel cells with proton-conducting Y:BaZrO3 electrolyte on porous anodic aluminum oxide substrate

    International Nuclear Information System (INIS)

    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/cm2 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

  12. 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.

  13. Electrolytic cell stack with molten electrolyte migration control

    Science.gov (United States)

    Kunz, H. Russell; Guthrie, Robin J.; Katz, Murray

    1988-08-02

    An electrolytic cell stack includes inactive electrolyte reservoirs at the upper and lower end portions thereof. The reservoirs are separated from the stack of the complete cells by impermeable, electrically conductive separators. Reservoirs at the negative end are initially low in electrolyte and the reservoirs at the positive end are high in electrolyte fill. During stack operation electrolyte migration from the positive to the negative end will be offset by the inactive reservoir capacity. In combination with the inactive reservoirs, a sealing member of high porosity and low electrolyte retention is employed to limit the electrolyte migration rate.

  14. Fundamental degradation mechanisms of layered oxide Li-ion battery cathode materials: Methodology, insights and novel approaches

    International Nuclear Information System (INIS)

    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 LiMO2 (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

  15. 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.

  16. 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.

  17. The cathode plasma simulation

    Science.gov (United States)

    Suksila, Thada

    Since its invention at the University of Stuttgart, Germany in the mid-1960, scientists have been trying to understand and explain the mechanism of the plasma interaction inside the magnetoplasmadynamics (MPD) thruster. Because this thruster creates a larger level of efficiency than combustion thrusters, this MPD thruster is the primary cadidate thruster for a long duration (planetary) spacecraft. However, the complexity of this thruster make it difficult to fully understand the plasma interaction in an MPD thruster while operating the device. That is, there is a great deal of physics involved: the fluid dynamics, the electromagnetics, the plasma dynamics, and the thermodynamics. All of these physics must be included when an MPD thruster operates. In recent years, a computer simulation helped scientists to simulate the experiments by programing the physics theories and comparing the simulation results with the experimental data. Many MPD thruster simulations have been conducted: E. Niewood et al.[5], C. K. J. Hulston et al.[6], K. D. Goodfellow[3], J Rossignol et al.[7]. All of these MPD computer simulations helped the scientists to see how quickly the system responds to the new design parameters. For this work, a 1D MPD thruster simulation was developed to find the voltage drop between the cathode and the plasma regions. Also, the properties such as thermal conductivity, electrical conductivity and heat capacity are temperature and pressure dependent. These two conductivity and heat capacity are usually definded as constant values in many other models. However, this 1D and 2D cylindrical symmetry MPD thruster simulations include both temperature and pressure effects to the electrical, thermal conductivities and heat capacity values interpolated from W. F. Ahtye [4]. Eventhough, the pressure effect is also significant; however, in this study the pressure at 66 Pa was set as a baseline. The 1D MPD thruster simulation includes the sheath region, which is the

  18. Structure and texture of electrolytic superconducting coatings of high-purity niobium

    Science.gov (United States)

    Kolosov, V. N.; Shevyrev, A. A.

    2014-08-01

    Modes of epitaxial growth of electrolytic superconducting coatings of high-purity niobium on substrates of niobium, molybdenum, and tungsten have been investigated. The dynamics of changes in the structure and texture of the coatings depending on the method of treatment of substrates, cathode current density, and thickness of the deposited niobium layer has been studied.

  19. 对流-扩散法制备多孔衬底支撑梯度结构电解质薄膜%FABRICATION OF POROUS SUBSTRATE-SUPPORTED ELECTROLYTE THIN FILMS WITH GRADIENT MICROSTRUCTURE VIA CONVECTION-DIFFUSION METHOD

    Institute of Scientific and Technical Information of China (English)

    田长安; 刘俊亮; 曾燕伟

    2006-01-01

    8% (in mole) yttria-stabilized zirconia (8-YSZ) electrolyte thin films with gradient microstructures were successfully fabricated on porous alumina (p-Al2O3) substrates as a model porous electrode for solid oxide fuel cells (SOFCs) via a constituent species convection-diffusion route. This novel technique is simple, economical and potentially suitable for the fabrication of electrode-supported electrolytes for planar SOFCs with large dimensions. With the help of scanning electron microscopy and X-ray angular dispersion analysis, it is found that the 8-YSZ films supported by p-Al2O3 are structurally composed of a dense surface layer (~10 μm in thickness) on top of the substrate, a uniform in-filling layer (~50 μm) just under the surface of the substrate and an immediate diffuse layer reaching as deep as ~250μm. The particular thickness of each part in this gradient profile may be changed with the convection-diffusion conditions.%以多孔氧化铝(porous alumina,p-Al2O3)为模型多孔电极衬底材料,利用对流-扩散效应成功制备得到了具有梯度结构的8%(以摩尔计)钇稳定氧化锆(yttria-stabilized zirconia,YSZ)电解质薄膜.该方法新颖、经济简单、适合于制备大尺寸平板型固体氧化物燃料电池中多孔电极支撑的电解质薄膜.利用扫描电镜和X射线角散分析技术对所制备电解质薄膜/p-Al2O3样品进行了微结构测试和表征.结果表明:由该方法在多孔衬底上实现的YSZ电解质薄膜由生长于衬底表面上的均匀致密层(≈10μm)和衬底表面下孔道中均匀填充层(≈50μm)与弥散填充层(≈250μm)构成,且各层厚度可通过改变对流-扩散沉积条件得到调节.

  20. 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.

  1. Electrolytic refining of gold

    OpenAIRE

    Wohlwill, Emil

    2008-01-01

    At the request of the editor of ELECTROCHEMICAL INDUSTRY, I herewith give some notes on the electrolytic method of gold refining, to supplement the article of Dr. Tuttle (Vol. I, page 157, January, 1903).

  2. 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.

  3. 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%.

  4. 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

  5. Anion-redox nanolithia cathodes for Li-ion batteries

    Science.gov (United States)

    Zhu, Zhi; Kushima, Akihiro; Yin, Zongyou; Qi, Lu; Amine, Khalil; Lu, Jun; Li, Ju

    2016-08-01

    The development of lithium–air batteries is plagued by a high potential gap (>1.2 V) between charge and discharge, and poor cyclability due to the drastic phase change of O2 (gas) and Ox‑ (condensed phase) at the cathode during battery operations. Here we report a cathode consisting of nanoscale amorphous lithia (nanolithia) confined in a cobalt oxide, enabling charge/discharge between solid Li2O/Li2O2/LiO2 without any gas evolution. The cathode has a theoretical capacity of 1,341 Ah kg‑1, a mass density exceeding 2.2 g cm‑3, and a practical discharge capacity of 587 Ah kg‑1 at 2.55 V versus Li/Li+. It also displays stable cycling performance (only 1.8% loss after 130 cycles in lithium-matched full-cell tests against Li4Ti5O12 anode), as well as a round-trip overpotential of only 0.24 V. Interestingly, the cathode is automatically protected from O2 gas release and overcharging through the shuttling of self-generated radical species soluble in the carbonate electrolyte.

  6. The use of Electrolyte Additives to Improve the High Temperature Resilience of Li-Ion Cells

    Science.gov (United States)

    Smart, Marshall C.; Lucht, B. L.; Ratnakumar, Bugga V.

    2007-01-01

    This viewgraph presentation reviews the use of electrolyte additves to improve the resillience of Lithium ion cells. The objective of this work is to identify lithium-ion electrolytes, which will lead to Li-ion cells with a wide operational temperature range (+60 to -60 C), and to develop Li-ion electrolytes which result in cells that display improved high temperature resilience. Significant improvement in the high temperature resilience of Li-ion cells containing these additives was observed, with the most dramatic benefit being displayed by addition of DMAc. When the electrochemical properties of the individual electrodes were analyzed, the degradation of the anode kinetics was slowed most dramatically by the incorporation of DMAc into the electrolytes. Whereas, the greatest retention in the cathode kinetics was observed in the cell containing the electrolyte with VC added.

  7. 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.

  8. 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.)

  9. Understanding and Overcoming the Challenges Posed by Electrode/Electrolyte Interfaces in Rechargeable Magnesium Batteries

    Directory of Open Access Journals (Sweden)

    Fuminori eMizuno

    2014-11-01

    Full Text Available Guided by the great achievements of lithium (Li-ion battery technologies, post Li-ion battery technologies have gained a considerable interest in recent years. Their success would allow us to realize a sustainable society, enabling us to mitigate issues like global warming and resource depletion. Of such technologies, Magnesium (Mg battery technologies have attracted attention as a high energy-density storage system due to the following advantages: (1 potentially high energy-density derived from a divalent nature, (2 low-cost due to the use of an earth abundant metal, and (3 intrinsic safety aspect attributed to non-dendritic growth of Mg. However, these notable advantages are downplayed by undesirable battery reactions and related phenomena. As a result, there are only a few working rechargeable Mg battery systems. One of the root causes for undesirable behavior is the sluggish diffusion of Mg2+ inside a host lattice. Another root cause is the interfacial reaction at the electrode/electrolyte boundary. For the cathode/electrolyte interface, Mg2+ in the electrolyte needs a solvation-desolvation process prior to diffusion inside the cathode. Apart from the solid electrolyte interface (SEI formed on the cathode, the divalent nature of Mg should cause kinetically slower solvation-desolvation processes than that of Li-ion systems. This would result in a high charge transfer resistance and a larger overpotential. On the contrary, for the anode/electrolyte interface, the Mg deposition and dissolution process depends on the electrolyte nature and its compatibility with Mg metal. Also, the Mg metal/electrolyte interface tends to change over time, and with operating conditions, suggesting the presence of interfacial phenomena on the Mg metal. Hence, the solvation-desolvation process of Mg has to be considered with a possible SEI. Here, we focus on the anode/electrolyte interface in a Mg battery, and discuss the next steps to improve the battery

  10. Nickel hexacyanoferrate, a versatile intercalation host for divalent ions from nonaqueous electrolytes

    Science.gov (United States)

    Lipson, Albert L.; Han, Sang-Don; Kim, Soojeong; Pan, Baofei; Sa, Niya; Liao, Chen; Fister, Timothy T.; Burrell, Anthony K.; Vaughey, John T.; Ingram, Brian J.

    2016-09-01

    New energy storage chemistries based on Mg ions or Ca ions can theoretically improve both the energy density and reduce the costs of batteries. To date there has been limited progress in implementing these systems due to the challenge of finding a high voltage high capacity cathode that is compatible with an electrolyte that can plate and strip the elemental metal. In order to accelerate the discovery of such a system, model systems are needed that alleviate some of the issues of incompatibility. This report demonstrates the ability of nickel hexacyanoferrate to electrochemically intercalate Mg, Ca and Zn ions from a nonaqueous electrolyte. This material has a relatively high insertion potential and low overpotential in the electrolytes used in this study. Furthermore, since it is not an oxide based cathode it should be able to resist attack by corrosive electrolytes such as the chloride containing electrolytes that are often used to plate and strip magnesium. This makes it an excellent cathode for use in developing and understanding the complex electrochemistry of multivalent ion batteries.

  11. Extended area cathode for transverse discharge gas lasers

    International Nuclear Information System (INIS)

    Laser cathodes of extended emission area are disclosed having a plurality of substantially aligned electrically conductive plates spaced from one another and disposed in respective planes perpendicular to the longitudinal axis of the laser housing. Adjacent plates are spaced by a spacing s selected to achieve the ''hollow'' cathode effect and satisfying the relation s = k/p where p is the laser gas pressure and k is a constant determined by the laser gas and lying in the range of from about 5 to about 20 torr-cm. In one embodiment the cathode plates are supported by and attached to a pair of longitudinally extending electrically conductive rods. In another embodiment the cathode consists of a laminated array of alternatively disposed aligned taller and shorter electrically conductive plates. (U.S.)

  12. 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.

  13. Novel approaches for fabrication of thin film layers for solid oxide electrolyte fuel cells

    Science.gov (United States)

    Murugesamoorthi, K. A.; Srinivasan, S.; Cocke, D. L.; Appleby, A. J.

    1990-01-01

    The main objectives of the SOFC (solid oxide fuel cell) project are to (1) identify viable and cost-effective techniques to prepare cell components for stable MSOFCs (monolithic SOFCs); (2) fabricate half and single cells; and (3) evaluate their performances. The approach used to fabricate stable MSOFCs is as follows: (1) the electrolyte layer is prepared in the form of a honeycomb structure by alloy oxidation and other cell components are deposited on it; (2) the electrolyte and anode layers are deposited on the cathode layer, which has a porous, honeycomb structure; and (3) the electrolyte and cathode layers are deposited on the anode layer. The current status of the project is reported.

  14. 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

    2015-11-01

    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.

  15. 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.

  16. Virtual cathode microwave devices -- Basics

    Energy Technology Data Exchange (ETDEWEB)

    Thode, L.E.; Snell, C.M.

    1991-01-01

    Unlike a conventional microwave tube, a virtual-cathode device operates above the space-charge limit where the depth of the space-charge potential can cause electron reflection. The region associated with this electron reflection is referred to as a virtual cathode. Microwaves can be generated through oscillations in the position of the virtual cathode and through the bunching of electrons trapped in a potential well between the real and virtual cathodes. These two mechanisms are competitive. There are three basic classes of virtual cathode devices: (1) reflex triode; (2) reditron and side-shoot vircator; and (3) reflex diode or vircator. The reflex diode is the highest power virtual-cathode device. For the reflex diode the energy exchange between the beam and electromagnetic wave occurs in both the axial and radial directions. In some designs the oscillating-virtual-cathode frequency exceeds the reflexing-electron frequency exceeds the oscillating-virtual-cathode frequency. For the flex diode a periodic disruption in magnetic insulation can modulate the high- frequency microwave power. Overall, particle-in-cell simulation predictions and axial reflex diode experiments are in good agreement. Although frequency stability and phase locking of the reflex diode have been demonstrated, little progress has been made in efficiency enhancement. 58 refs., 11 figs.

  17. Virtual cathode microwave devices: Basics

    Science.gov (United States)

    Thode, L. E.; Snell, C. M.

    Unlike a conventional microwave tube, a virtual-cathode device operates above the space-charge limit where the depth of the space-charge potential can cause electron reflection. The region associated with this electron reflection is referred to as a virtual cathode. Microwaves can be generated through oscillations in the position of the virtual cathode and through the bunching of electrons trapped in a potential well between the real and virtual cathodes. These two mechanisms are competitive. There are three basic classes of virtual cathode devices: (1) reflex triode; (2) reditron and side-shoot vircator; and (3) reflex diode or vircator. The reflex diode is the highest power virtual-cathode device. For the reflex diode the energy exchange between the beam and electromagnetic wave occurs in both the axial and radial directions. In some designs the oscillating virtual-cathode frequency exceeds the reflexing-electron frequency while in other designs the reflexing-electron frequency exceeds the oscillating virtual-cathode frequency. For the flex diode, a periodic disruption in magnetic insulation can modulate the high-frequency microwave power. Overall, particle-in-cell simulation predictions and axial reflex diode experiments are in good agreement. Although frequency stability and phase locking of the reflex diode have been demonstrated, little progress has been made in efficiency enhancement.

  18. 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.

  19. High speed electrostatic photomultiplier tube for the 1.06 micrometer wavelength. Cup and slat dynode chain combined with flat cathode and coax output produces 0.25 nsec rise time

    Science.gov (United States)

    Sparks, S. D.

    1973-01-01

    The Varian cup and slat dynode chain was modified to have a flat cathode. These modifications were incorporated in an all-electrostatic photomultiplier tube having a rise time of 0.25 n sec. The tube delivered under the contract had a flat S-20 opaque cathode with a useful diameter of 5 mm. The design of the tube is such that a III to V cathode support is mounted in place of the existing cathode substrate. This cathode support is designed to accept a transferred III to V cathode and maintain the cathode surface in the same position as the S-20 photocathode.

  20. Improved Cathode Structure for a Direct Methanol Fuel Cell

    Science.gov (United States)

    Valdez, Thomas; Narayanan, Sekharipuram

    2005-01-01

    An improved cathode structure on a membrane/electrode assembly has been developed for a direct methanol fuel cell, in a continuing effort to realize practical power systems containing such fuel cells. This cathode structure is intended particularly to afford better cell performance at a low airflow rate. A membrane/electrode assembly of the type for which the improved cathode structure was developed (see Figure 1) is fabricated in a process that includes brush painting and spray coating of catalyst layers onto a polymer-electrolyte membrane and onto gas-diffusion backings that also act as current collectors. The aforementioned layers are then dried and hot-pressed together. When completed, the membrane/electrode assembly contains (1) an anode containing a fine metal black of Pt/Ru alloy, (2) a membrane made of Nafion 117 or equivalent (a perfluorosulfonic acid-based hydrophilic, proton-conducting ion-exchange polymer), (3) a cathode structure (in the present case, the improved cathode structure described below), and (4) the electrically conductive gas-diffusion backing layers, which are made of Toray 060(TradeMark)(or equivalent) carbon paper containing between 5 and 6 weight percent of poly(tetrafluoroethylene). The need for an improved cathode structure arises for the following reasons: In the design and operation of a fuel-cell power system, the airflow rate is a critical parameter that determines the overall efficiency, cell voltage, and power density. It is desirable to operate at a low airflow rate in order to obtain thermal and water balance and to minimize the size and mass of the system. The performances of membrane/electrode assemblies of prior design are limited at low airflow rates. Methanol crossover increases the required airflow rate. Hence, one way to reduce the required airflow rate is to reduce the effect of methanol crossover. Improvement of the cathode structure - in particular, addition of hydrophobic particles to the cathode - has been

  1. Electrochemical Model for Ionic Liquid Electrolytes in Lithium Batteries

    International Nuclear Information System (INIS)

    ABSTRACT: Room temperature ionic liquids are considered as potential electrolytes for high performance and safe lithium batteries due to their very low vapor pressure and relatively wide electrochemical and thermal stability windows. Unlike organic electrolytes, ionic liquid electrolytes are molten salts at room temperature with dissociated cations and anions. These dissociated ions interfere with the transport of lithium ions in lithium battery. In this study, a mathematical model is developed for transport of ionic components to study the performance of ionic liquid based lithium batteries. The mathematical model is based on a univalent ternary electrolyte frequently encountered in ionic liquid electrolytes of lithium batteries. Owing to the very high concentration of components in ionic liquid, the transport of lithium ions is described by the mutual diffusion phenomena using Maxwell-Stefan diffusivities, which are obtained from atomistic simulation. The model is employed to study a lithium-ion battery where the electrolyte comprises ionic liquid with mppy+ (N-methyl-N-propyl pyrrolidinium) cation and TFSI− (bis trifluoromethanesulfonyl imide) anion. For a moderate value of reaction rate constant, the electric performance results predicted by the model are in good agreement with experimental data. We also studied the effect of porosity and thickness of separator on the performance of lithium-ion battery using this model. Numerical results indicate that low rate of lithium ion transport causes lithium depleted zone in the porous cathode regions as the porosity decreases or the length of the separator increases. The lithium depleted region is responsible for lower specific capacity in lithium-ion cells. The model presented in this study can be used for design of optimal ionic liquid electrolytes for lithium-ion and lithium-air batteries

  2. Preparation and properties of biodegradable polymer-layered silicate nanocomposite electrolytes for zinc based batteries

    International Nuclear Information System (INIS)

    Highlights: • Organically modified MMT is used as nanofiller to enhance the properties of the polymer PCL-zinc triflate salt complex. • The nanocomposite showed enhancement in conductivity, excellent electrochemical and thermal stability. • Cyclic voltammetry revealed feasibility of intercalation/deintercalation of Zn2+ ions with MnO2 cathode. • Best conducting electrolyte showed remarkable degradability in soil compost over a period of 90 days. - Abstract: Polymer-layered silicate nanocomposite electrolytes (PLSNEs) were prepared by utilizing a biodegradable polymer namely poly(ϵ-caprolactone) as host polymer and zinc triflate as dopant salt with the incorporation of varying concentrations of octadecylamine modified montmorillonite nanoclay and further characterized using various experimental techniques. A maximum conductivity of 9.5 × 10−5 S cm−1 was achieved for a 15 wt% loading of the nanoclay. X-ray diffraction and differential scanning calorimetric studies revealed the change occurring in the crystalline behavior of the electrolyte as a result of incorporation of the nanoclay. An appreciably good thermal and electrochemical stability was also observed thus suggesting applicability of the prepared electrolyte in commericial systems and therefore the feasibility of reduction and oxidation processes of MnO2 cathode with the prepared electrolyte system has also been evaluated by means of cyclic voltammetry. The best conducting sample of the polymer electrolyte showed a remarkable degradability over a degradation period of 90 days in soil compost

  3. 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.

  4. 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.

  5. Electrolytic hydrogen production

    Science.gov (United States)

    Ramani, M. P. S.

    In the role of a secondary energy carrier complementary to electricity in a postfossil-fuel era, hydrogen produced by the elecrolytic splitting of water may be obtained by a variety of methods whose technology development status is presently assessed. Nuclear heat can be converted into hydrogen either directly, via thermal splitting of water, or by means of water electrolysis, which can be of the unipolar tank type or the bipolar filter-press type. An evaluation is made of advanced electrolytic techniques involving exotic materials, as well as solid polymer electrolyte electrolysis and high-temperature water-vapor electrolysis.

  6. 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.

  7. 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.)

  8. 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.

  9. 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.

  10. 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

  11. Microwave energy application on carbon cathode for high efficient microbial electrosynthesis

    Science.gov (United States)

    Nie, Huarong; Cui, Mengmeng; Zhang, Tian; Lovley, Derek; Russell, Thomas

    2013-03-01

    Microbial electrosynthesis represents a promising strategy of energy storage through microbial conversion of carbon dioxide to transportation fuels or other organic commodities. One key feature for its commercialization is to enhance the cathode performance associated with microbial inoculums. A biocompatible, high surface area, multi-level porous cathode was developed from microwave pyrolysis of ferrocene on carbon felt to support the microorganism to produce acetate from carbon dioxide. The formed nanostructure flake composite on fibers increased the biofilm-cathode interfacial surface area, the interaction between the cathode surface and the microbial biofilm and the electractivity of cathode, while the macroscale porous structure of the intertwined carbon fibers provides easy microbe access. Around 743 mM cm-2 d-1 of acetate was generated by Sporomusa, which is 3.2 fold larger than the reported highest value coming from the chitosan coated carbon cloth cathode.

  12. 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.

  13. Metal supported tubular solid oxide fuel cells fabricated by suspension plasma spray and suspension high velocity oxy-fuel spray

    Science.gov (United States)

    Yoo, Yeong; Wang, Youliang; Deng, Xiaohua; Singh, Devinder; Legoux, Jean-Gabriel

    2012-10-01

    Low temperature (LT) metal supported solid oxide fuel cells (SOFCs) have many advantages in comparison to conventional electrode or electrolyte supported type SOFCs. NRC has demonstrated high performance LT metal supported planar SOFCs fabricated by either wet colloidal spray/sintering or suspension thermal spray. The combination of tubular configuration and metal supported SOFCs may produce more unique and very attractive advantages such as easy and inexpensive sealing method and materials, high specific and volumetric power density, cost-effective fabrication, enhanced robustness, rapid start up, red-ox cycle tolerance and potential use for a pressurized integrated system. In this paper, thin film solid electrolyte of Sm0.2Ce0.8O1.90 (SDC) and NiO-SDC composite anode on sintered porous tubular metal supports were deposited by suspension HVOF spray and suspension plasma spray, respectively on sintered porous tubular metal support. La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) cathode on the SDC electrolyte was formed by wet colloidal spray and subsequent sintering process as the final fabrication step. The detailed investigation of suspension and process-related parameters for suspension thermal spray was performed in order to produce thin and crack-free SDC thin film coatings. The electrochemical performance of single cells was demonstrated.

  14. Atomic to Nanoscale Investigation of Functionalities of Al2O3 Coating Layer on Cathode for Enhanced Battery Performance

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Pengfei; Zheng, Jianming; Zhang, Xiaofeng; Xu, Rui; Amine, Khalil; Xiao, Jie; Zhang, Jiguang; Wang, Chong M.

    2016-01-06

    Surface coating of cathode has been identified as an effective approach for enhancing the capacity retention of layered structure cathode. However, the underlying operating mechanism of such a thin layer of coating, in terms of surface chemical functionality and capacity retention, remains unclear. In this work, we use aberration corrected scanning transmission electron microscopy and high efficient spectroscopy to probe the delicate functioning mechanism of Al2O3 coating layer on Li1.2Ni0.2Mn0.6O2 cathode. We discovered that in terms of surface chemical function, the Al2O3 coating suppresses the side reaction between cathode and the electrolyte upon the battery cycling. At the same time, the Al2O3 coating layer also eliminates the chemical reduction of Mn from the cathode particle surface, therefore avoiding the dissolution of the reduced Mn into the electrolyte. In terms of structural stability, we found that the Al2O3 coating layer can mitigate the layer to spinel phase transformation, which otherwise will initiate from the particle surface and propagate towards the interior of the particle with the progression of the battery cycling. The atomic to nanoscale effects of the coating layer observed here provide insight for optimized design of coating layer on cathode to enhance the battery properties.

  15. Effect of the hydrodynamic conditions of electrolyte flow on critical states in electrochemical machining

    Directory of Open Access Journals (Sweden)

    Sawicki Jerzy

    2015-01-01

    Full Text Available The paper presents the results of experimental studies of electrochemical machining process oriented on occurring in the treatment critical states caused by electrolyte flow hydrodynamic conditions in the gap between electrodes. Material forming in electrochemical machining is carried out by anodic dissolution. In general in ECM process, the essence of the treatment is that the workpiece is the anode and the tool is the cathode. The space between the anode and cathode is filled by electrolyte. The current flow between the electrodes causes anodic dissolution process, resulting in the removal of material from the anode. Choosing in the process of electrochemical machining, respectively: anode and cathode material, electrolyte and processing parameters, such conditions can be created that enable a high process efficiency and smoothness of the surface. Inappropriate selection of machining parameters can cause the emergence of critical states in the ECM, which are mainly related to the flow of the electrolyte in the gap between electrodes. This work is an attempt to assess the occurring critical states in ECM on the example of machining of curved surfaces with any sort of outline and curved rotating surfaces.

  16. Dopamine as a Novel Electrolyte Additive for High-Voltage Lithium-Ion Batteries.

    Science.gov (United States)

    Lee, Hoogil; Han, Taeyeong; Cho, Kuk Young; Ryou, Myung-Hyun; Lee, Yong Min

    2016-08-24

    Dopamine, which can be electrochemically oxidized to polydopamine on cathode surface, was introduced as an electrolyte additive for high-voltage lithium-ion batteries (LIBs). The addition of 0.1 wt % dopamine to the electrolyte led to the formation of a polydopamine-containing layer on the cathode, thereby resulting in suppression of the oxidative decomposition of the electrolyte during high-voltage operation (up to 4.5 V) of a LiNi1/3Co1/3Mn1/3O2/artificial graphite cell. The addition of dopamine to the electrolyte improved the capacity retention of the cell from 136 to 147 mAh g(-1) after 100 cycles at a rate of 1 C and a cutoff voltage of 4.5 V, while the cycle performance and rate capability with a cutoff voltage of 4.3 V were comparable to those of the cell without dopamine. Further evidence of the positive impact of dopamine on high-voltage LIBs was the lower DC-IRs and AC impedances, as well as the retention of the cathode morphology even after operation at 4.5 V. PMID:27509406

  17. 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.

  18. Sulfurized carbon: a class of cathode materials for high performance lithium/sulfur batteries

    Directory of Open Access Journals (Sweden)

    Sheng S. Zhang

    2013-12-01

    Full Text Available Liquid electrolyte lithium/sulfur (Li/S batteries cannot come into practical applications because of many problems such as low energy efficiency, short cycle life, and fast self-discharge. All these problems are related to the dissolution of lithium polysulfide, a series of sulfur reduction intermediates, in the liquid electrolyte, and resulting parasitic reactions with the Li anode. Covalently binding sulfur onto carbon surface is a solution to completely eliminate the dissolution of lithium polysulfide and make the Li/S battery viable for practical applications. This can be achieved by replacing elemental sulfur with sulfurized carbon as the cathode material. This article reviews the current efforts on this subject and discusses the syntheses, electrochemical properties, and prospects of the sulfurized carbon as a cathode material in the rechargeable Li/S batteries.

  19. 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)

  20. 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.

  1. Nickel fibers/sulfur composites cathode with enhanced electrochemical performance for rechargeable lithium-sulfur batteries

    International Nuclear Information System (INIS)

    Highlights: • A novel Nickel fibers was developed as additive for sulfur cathode. • Composite cathode containing 3% nickel fibers has remarkable cycling stability and great rate capability. • Electrochemical analysis shows nickel fibers can absorb polysulfides, improve electronic conductivity, and facilitate the redox reactions in sulfur cathode. - Abstract: The commercialization of lithium sulfur batteries have so far hindered by the low electrochemical utilization and rapid capacity fading of sulfur cathode, which is induced by low electron conductivity and high dissolution of intermediate polysulfides. Recent studies have shown that the metal (Pt, Au, Ni) as electrocatalyst of lithium polysulfides and its metallic porous nanostructure can suppress the shuttle effect. In this work, we use the porous nanostructure of nickel fibers/sulfur as-designed composite cathode material for lithium sulfur batteries. The initial discharge capacity of the cathode with the added 3(%) nickel fibers was 805 mAh g−1, and the remaining capacity was 440 mAh g−1 after 50 cycles at 0.766 mA cm−2. Even at a high current density of 1.532 mA cm−2, it also kept a high discharge capacity of 310 mAh g−1. Compared with pure sulfur electrodes, the electrodes containing nickel fibers showed an obviously improved cycle and rate performances, confirming that metallic porous nanostructure of nickel can not only contribute to reducing the dissolution of polysulfides into electrolytes, but also has a catalytic effect on the redox reactions during charge-discharge process

  2. Selenium and selenium-sulfur cathode materials for high-energy rechargeable magnesium batteries

    Science.gov (United States)

    Zhao-Karger, Zhirong; Lin, Xiu-Mei; Bonatto Minella, Christian; Wang, Di; Diemant, Thomas; Behm, R. Jürgen; Fichtner, Maximilian

    2016-08-01

    Magnesium (Mg) is an attractive metallic anode material for next-generation batteries owing to its inherent dendrite-free electrodeposition, high capacity and low cost. Here we report a new class of Mg batteries based on both elemental selenium (Se) and selenium-sulfur solid solution (SeS2) cathode materials. Elemental Se confined into a mesoporous carbon was used as a cathode material. Coupling the Se cathode with a metallic Mg anode in a non-nucleophilic electrolyte, the Se cathode delivered a high initial volumetric discharge capacity of 1689 mA h cm-3 and a reversible capacity of 480 mA h cm-3 was retained after 50 cycles at a high current density of 2 C. The mechanistic insights into the electrochemical conversion in Mg-Se batteries were investigated by microscopic and spectroscopic methods. The structural transformation of cyclic Se8 into chainlike Sen upon battery cycling was revealed by ex-situ Raman spectroscopy. In addition, the promising battery performance with a SeS2 cathode envisages the perspective of a series of SeSn cathode materials combining the benefits of both selenium and sulfur for high energy Mg batteries.

  3. Thermally cured semi-interpenetrating electrolyte networks (s-IPN) for safe and aging-resistant secondary lithium polymer batteries

    Science.gov (United States)

    Nair, Jijeesh R.; Destro, Matteo; Bella, Federico; Appetecchi, Giovanni B.; Gerbaldi, Claudio

    2016-02-01

    Truly solid polymer electrolyte membranes are designed by thermally induced free radical polymerisation. The overall membrane architecture is built on a semi-interpenetrating polymer network (s-IPN) structure, where a di-methacrylate oligomer is cross-linked (in situ) in the presence of a long thermoplastic linear PEO chain and a supporting lithium salt to obtain a freestanding, flexible and non-tacky film. In the envisaged systems, the di-methacrylate functions as a soft cross-linker, thus avoiding physico-mechanical deformation of the s-IPNs at elevated temperature, without hampering the ionic conductivity. s-IPNs exhibit remarkable stability towards lithium metal and no traces of impurity are detected while testing their oxidation stability (4.7 V vs. Li/Li+) towards anodic potential. The newly elaborated system is also successfully tested at moderately high temperature in Li metal cells in which LiFePO4/C is used as the cathode active material, showing excellent indications of safe and highly durable electrolyte separator (i.e., 2000 cycles at reasonably high 1C rate).

  4. 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).

  5. 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.

  6. 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.

  7. 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.

  8. Role of Chloride for a Simple, Non-Grignard Mg Electrolyte in Ether-Based Solvents.

    Science.gov (United States)

    Sa, Niya; Pan, Baofei; Saha-Shah, Anumita; Hubaud, Aude A; Vaughey, John T; Baker, Lane A; Liao, Chen; Burrell, Anthony K

    2016-06-29

    Mg battery operates with Chevrel phase (Mo6S8, ∼1.1 V vs Mg) cathodes that apply Grignard-based or derived electrolytes, which allow etching of the passivating oxide coating forms at the magnesium metal anode. Majority of Mg electrolytes studied to date are focused on developing new synthetic strategies to achieve a better reversible Mg deposition. While most of these electrolytes contain chloride as a component, and there is a lack of literature which investigates the fundamental role of chloride in Mg electrolytes. Further, ease of preparation and potential safety benefits have made simple design of magnesium electrolytes an attractive alternative to traditional air sensitive Grignard reagents-based electrolytes. Work presented here describes simple, non-Grignard magnesium electrolytes composed of magnesium bis(trifluoromethane sulfonyl)imide mixed with magnesium chloride (Mg(TFSI)2-MgCl2) in tetrahydrofuran (THF) and diglyme (G2) that can reversibly plate and strip magnesium. Based on this discovery, the effect of chloride in the electrolyte complex was investigated. Electrochemical properties at different initial mixing ratios of Mg(TFSI)2 and MgCl2 showed an increase of both current density and columbic efficiency for reversible Mg deposition as the fraction content of MgCl2 increased. A decrease in overpotential was observed for rechargeable Mg batteries with electrolytes with increasing MgCl2 concentration, evidenced by the coin cell performance. In this work, the fundamental understanding of the operation mechanisms of rechargeable Mg batteries with the role of chloride content from electrolyte could potentially bring rational design of simple Mg electrolytes for practical Mg battery. PMID:27255422

  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. 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.

  11. On the dispersion of lithium-sulfur battery cathode materials effected by electrostatic and stereo-chemical factors of binders

    Science.gov (United States)

    Hong, Xiaoheng; Jin, Jun; Wen, Zhaoyin; Zhang, Sanpei; Wang, Qingsong; Shen, Chen; Rui, Kun

    2016-08-01

    Sodium carboxymethyl cellulose-styrene butadiene rubber (CMC-SBR), sodium alginate (SA) and LA132 are utilized as the polymer binders for the cathodes of Li-S batteries to study their dispersion mechanism on the cathode materials and the consequent influence on the performance of Li-S batteries. Zeta potential tests, differential scanning calorimetry analysis and calculations of the rotational barriers of the links of the polymer chains by General Atomic and Molecular Electronic Structure System (GAMESS) reveal that higher charge densities and better chain flexibility of the binders promise the dispersion of the downsized cathode materials. LA132 is found to have optimal characteristic for dispersing and stabilizing the cathode materials in aqueous environment. The cycling performance and SEM images of the cathodes demonstrate that cathodes with higher dispersion degree achieve higher discharge capacities. The electrochemical impedance spectroscopy (EIS) results further support that better dispersed cathodes have lower impedance resulting from their well established conducting frameworks.

  12. Analysis of cell performance and thermal regeneration of a lithium-tin cell having an immobilized fused-salt electrolyte

    Science.gov (United States)

    Cairns, E. J.; Shimotake, H.

    1969-01-01

    Cell performance and thermal regeneration of a thermally regenerative cell uses lithium and tin and a fused-salt electrolyte. The emf of the Li-Sn cell, as a function of cathode-alloy composition, is shown to resemble that of the Na-Bi cell.

  13. Surface effects induced by cathodic hydrogenation in type AISI 304 stainless steel

    International Nuclear Information System (INIS)

    Cathodic hydrogen charging of type AISI 304 stainless steel modified its austenitic structure, giving rise to the formation of two new martensitic phases and the appearance of cracks, in most cases delayed. As electrolyte a 1 N H2 S O4 solution containing As2 O3 was employed. The cathodic hydrogenation was carries out at room temperature. The transformed phases were identified with black and white and coloured metallographic techniques, as well as by X-ray diffraction. The effect of cathodic hydrogenation in samples uniaxially tensile tested with constant nominal strain rate was investigated. It was concluded that the number of cracks per unit surface area changes with hydrogenation conditions and that hydrogen should be present for the embrittlement to occur. (author)

  14. Rare earth metal oxides as BH4-tolerance cathode electrocatalysts for direct borohydride fuel cells

    Institute of Scientific and Technical Information of China (English)

    NI Xuemin; WANG Yadong; GUO Feng; YAO Pei; PAN Mu

    2012-01-01

    Rare earth metal oxides (REMO) as cathode electrocatalysts in direct borohydride fuel cell (DBFC) were investigated.The REMO electrocatalysts tested showed favorable activity to the oxygen electro-reduction reaction and strong tolerance to the attack of BH4- in alkaline electrolytes.The simple membraneless DBFCs using REMO as cathode electrocatalyst and using hydrogen storage alloy as anodic electrocatalyst exhibited an open circuit of about 1 V and peak power of above 60 mW/cm2.The DBFC using Sm2O3 as cathode electrocatalyst showed a relatively better performance.The maximal power density of 76.2 mW/cm2 was obtained at the cell voltage of 0.52 V.

  15. 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.

  16. 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

  17. 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.

  18. 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

  19. 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. PMID:26761603

  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. 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.

  2. In situ formed lithium sulfide/microporous carbon cathodes for lithium-ion batteries.

    Science.gov (United States)

    Zheng, Shiyou; Chen, Yvonne; Xu, Yunhua; Yi, Feng; Zhu, Yujie; Liu, Yihang; Yang, Junhe; Wang, Chunsheng

    2013-12-23

    Highly stable sulfur/microporous carbon (S/MC) composites are prepared by vacuum infusion of sulfur vapor into microporous carbon at 600 °C, and lithium sulfide/microporous carbon (Li2S/MC) cathodes are fabricated via a novel and facile in situ lithiation strategy, i.e., spraying commercial stabilized lithium metal powder (SLMP) onto a prepared S/MC film cathode prior to the routine compressing process in cell assembly. The in situ formed Li2S/MC film cathode shows high Coulombic efficiency and long cycling stability in a conventional commercial Li-ion battery electrolyte (1.0 M LiPF6 + EC/DEC (1:1 v/v)). The reversible capacities of Li2S/MC cathodes remain about 650 mAh/g even after 900 charge/discharge cycles, and the Coulombic efficiency is close to 100% at a current density of 0.1C, which demonstrates the best electrochemical performance of Li2S/MC cathodes reported to date. Furthermore, this Li2S/MC film cathode fabricated via our in situ lithiation strategy can be coupled with a Li-free anode, such as graphite, carbon/tin alloys, or Si nanowires to form a rechargeable Li-ion cell. As the Li2S/MC cathode is paired with a commercial graphite anode, the full cell of Li2S/MC-graphite (Li2S-G) shows a stable capacity of around 600 mAh/g in 150 cycles. The Li2S/MC cathodes prepared by high-temperate sulfur infusion and SLMP prelithiation before cell assembly are ready to fit into current Li-ion batteries manufacturing processes and will pave the way to commercialize low-cost Li2S-G Li-ion batteries. PMID:24251957

  3. Modeling study of a Li–O2 battery with an active cathode

    International Nuclear Information System (INIS)

    In this study, a new organic lithium oxygen (Li–O2) battery structure is proposed to enhance battery capacity. The electrolyte is forced to recirculate through the cathode and then saturated with oxygen in a tank external to the battery. The forced convection enhances oxygen transport and alleviates the problem of electrode blockage during discharge. A two dimensional, transient, non-isothermal simulation model is developed to study the heat and mass transfer within the battery and validate the proposed design. Results show that this novel active cathode design improves the battery capacity at all discharge current densities. The capacity of the Li–O2 battery is increased by 15.5 times (from 12.2 mAh g−1 to 201 mAh g−1) at the discharge current of 2.0 mA cm−2 when a conventional passive electrode is replaced by the newly designed active electrode. Furthermore, a cathode with non-uniform porosity is suggested and simulation results show that it can reach a higher discharge capacity without decreasing its power density. Detailed mass transport processes in the battery are also studied. - Highlights: • Electrolyte is circulated through the cathode and externally saturated with oxygen. • A two-dimensional, transient, non-isothermal model is developed for a Li–O2 battery. • The new design's capacity can be 15.5 times that of a battery with passive cathode. • A cathode with non-uniform porosity is proposed to further enhance battery capacity

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Composite cathode materials development for intermediate temperature solid oxide fuel cell systems

    Science.gov (United States)

    Qin, Ya

    Solid oxide fuel cell (SOFC) systems are of particular interest as electrochemical power systems that can operate on various hydrocarbon fuels with high fuel-to-electrical energy conversion efficiency. Within the SOFC stack, La0.8Sr 0.2Ga0.8Mg0.115Co0.085O3-delta (LSGMC) has been reported as an optimized composition of lanthanum gallate based electrolytes to achieve higher oxygen ionic conductivity at intermediate temperatures, i.e., 500-700°C. The electrocatalytic properties of interfaces between LSGMC electrolytes and various candidate intermediate-temperature SOFC cathodes have been investigated. Sm0.5Sr0.5CoO 3-delta (SSC), and La0.6Sr0.4Co0.2Fe 0.8O3-delta (LSCF), in both pure and composite forms with LSGMC, were investigated with regards to both oxygen reduction and evolution, A range of composite cathode compositions, having ratios of SSC (in wt.%) with LSGMC (wt.%) spanning the compositions 9:1, 8:2, 7:3, 6:4 and 5:5, were investigated to determine the optimal cathode-electrolyte interface performance at intermediate temperatures. All LSGMC electrolyte and cathode powders were synthesized using the glycine-nitrate process (GNP). Symmetrical electrochemical cells were investigated with three-electrode linear dc polarization and ac impedance spectroscopy to characterize the kinetics of the interfacial reactions in detail. Composite cathodes were found to perform better than the single phase cathodes due to significantly reduced polarization resistances. Among those composite SSC-LSGMC cathodes, the 7:3 composition has demonstrated the highest current density at the equivalent overpotential values, indicating that 7:3 is an optimal mixing ratio of the composite cathode materials to achieve the best performance. For the composite SC-LSGMC cathode/LSGMC interface, the cathodic overpotential under 1 A/cm2 current density was as low as 0.085 V at 700°C, 0.062V at 750°C and 0.051V at 800°C in air. Composite LSCF-LSGMC cathode/LSGMC interfaces were found to have

  10. Mechanistic Insight in the Function of Phosphite Additives for Protection of LiNi0.5Co0.2Mn0.3O2 Cathode in High Voltage Li-Ion Cells.

    Science.gov (United States)

    He, Meinan; Su, Chi-Cheung; Peebles, Cameron; Feng, Zhenxing; Connell, Justin G; Liao, Chen; Wang, Yan; Shkrob, Ilya A; Zhang, Zhengcheng

    2016-05-11

    Triethlylphosphite (TEP) and tris(2,2,2-trifluoroethyl) phosphite (TTFP) have been evaluated as electrolyte additives for high-voltage Li-ion battery cells using a Ni-rich layered cathode material LiNi0.5Co0.2Mn0.3O2 (NCM523) and the conventional carbonate electrolyte. The repeated charge/discharge cycling for cells containing 1 wt % of these additives was performed using an NCM523/graphite full cell operated at the voltage window from 3.0-4.6 V. During the initial charge process, these additives decompose on the cathode surface at a lower oxidation potential than the baseline electrolyte. Impedance spectroscopy and post-test analyses indicate the formation of protective coatings by both additives on the cathode surface that prevent oxidative breakdown of the electrolyte. However, only TTFP containing cells demonstrate the improved capacity retention and Coulombic efficiency. For TEP, the protective coating is also formed, but low Li(+) ion mobility through the interphase layer results in inferior performance. These observations are rationalized through the inhibition of electrocatalytic centers present on the cathode surface and the formation of organophosphate deposits isolating the cathode surface from the electrolyte. The difference between the two phosphites clearly originates in the different properties of the resulting phosphate coatings, which may be in Li(+) ion conductivity through such materials. PMID:27090502

  11. Ceramic electrolyte coating and methods

    Science.gov (United States)

    Seabaugh, Matthew M.; Swartz, Scott L.; Dawson, William J.; McCormick, Buddy E.

    2007-08-28

    Aqueous coating slurries useful in depositing a dense coating of a ceramic electrolyte material (e.g., yttrium-stabilized zirconia) onto a porous substrate of a ceramic electrode material (e.g., lanthanum strontium manganite or nickel/zirconia) and processes for preparing an aqueous suspension of a ceramic electrolyte material and an aqueous spray coating slurry including a ceramic electrolyte material. The invention also includes processes for depositing an aqueous spray coating slurry including a ceramic electrolyte material onto pre-sintered, partially sintered, and unsintered ceramic substrates and products made by this process.

  12. 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...

  13. 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....

  14. Separation of Fluoride Ions in an Electrolytic Cell by Using an AnionExchange Membrane

    International Nuclear Information System (INIS)

    Separation of fluoride ions in an electrolytic cell with an anionexchange membrane which is so-called an electrodialysis process has beenperformed. The experiment have been taken place in room temperature in anelectrolytic cell made by plexiglas consisted on anode and cathode chambersseparated by an anion exchange membrane in dimension of 4 x 4 cm. The carbonand stainless steel are applied as an anode and platinum as s' cathode. Theanolyte is a HNO3 0.3 M solution, while a solution of NaF 0.3 M, and amixture of NaF 0.3 M containing uranyl nitrate solution for separating offluoride ions and uranium are used as a catholyte. The distance between theelectrode and the membrane is 1.5 cm and this distance is kept constant. Theparameters observed are the current voltage, cathode applied, and uraniumconcentration. For the solution without uranium, the results show that thefluoride ions transferred are around 50 % using carbon as a cathode for 3hours and the voltage of 10 volts, while for SS as a cathode are around 93 %.For the solution containing uranium, the fluoride ions transferred are around78 % for 3.5 hours and the uranium ions remain in the catholyte in which mostof them are as 8 yellow deposit of Na2U2O7 on the cathode surface andothers are as a white precipitate of NaUF5 on the bottom of the cathodechamber. (author)

  15. Hollow cathode arc: effect of the cathode material on the internal plasma

    International Nuclear Information System (INIS)

    In discharges with hollow cathodes functioning in the arc regime, the cathode emits thermionic electrons which ionize the gas. To reduce the electrical power consumed by these discharges, cathodes made of thoriated tungsten and lathanum hexaboride have been used. The parameters of the plasma generated into the cathode have been measured with electrostatic probes. (Auth.)

  16. Development of highly active and stable hybrid cathode catalyst for PEMFCs

    Science.gov (United States)

    Jung, Won Suk

    Polymer electrolyte membrane fuel cells (PEMFCs) are attractive power sources of the future for a variety of applications including portable electronics, stationary power, and automobile application. However, sluggish cathode kinetics, high Pt cost, and durability issues inhibit the commercialization of PEMFCs. To overcome these drawbacks, research has been focused on alloying Pt with transition metals since alloy catalysts show significantly improved catalytic properties like high activity, selectivity, and durability. However, Pt-alloy catalysts synthesized using the conventional impregnation method exhibit uneven particle size and poor particle distribution resulting in poor performance and/or durability in PEMFCs. In this dissertation, a novel catalyst synthesis methodology is developed and compared with catalysts prepared using impregnation method and commercial catalysts. Two approaches are investigated for the catalyst development. The catalyst durability was studied under U. S. DRIVE Fuel Cell Tech Team suggested protocols. In the first approach, the carbon composite catalyst (CCC) having active sites for oxygen reduction reaction (ORR) is employed as a support for the synthesis of Pt/CCC catalyst. The structural and electrochemical properties of Pt/CCC catalyst are investigated using high-resolution transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy, while RDE and fuel cell testing are carried out to study the electrochemical properties. The synergistic effect of CCC and Pt is confirmed by the observed high activity towards ORR for the Pt/CCC catalyst. The second approach is the synthesis of Co-doped hybrid cathode catalysts (Co-doped Pt/CCC) by diffusing the Co metal present within the CCC support into the Pt nanoparticles during heat-treatment. The optimized Co-doped Pt/CCC catalyst performed better than the commercial catalysts and the catalyst prepared using the impregnation method in PEMFCs and showed high

  17. 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.

  18. Preparation of tantalum carbide films by reaction of electrolytic carbon coating with the tantalum substrate

    OpenAIRE

    Massot, Laurent; Chamelot, Pierre; Taxil, Pierre

    2006-01-01

    This article demonstrates that coatings of tantalum carbide can be obtained by electrodeposition of carbon in molten fluorides on a tantalum substrate as an alternative to the CVD process. The structural characteristics of the carbon deposited by the electrolytic route lead to a high reactivity of this element towards a tantalum cathode to produce tantalum carbide. Mutual reactivity was shown to be enhanced if tantalum plate is replaced by an electrodeposited layer of tantalum, where th...

  19. Operando X-ray Investigation of Electrode/Electrolyte Interfaces in Model Solid Oxide Fuel Cells

    OpenAIRE

    Volkov, Sergey; Vonk, Vedran; Khorshidi, Navid; Franz, Dirk; Kubicek, Markus; Kilic, Volkan; Felici, Roberto; Huber, Tobias M.; Navickas, Edvinas; Rupp, Ghislain M.; Fleig, Jürgen; Stierle, Andreas

    2016-01-01

    We employed operando anomalous surface X-ray diffraction to investigate the buried interface between the cathode and the electrolyte of a model solid oxide fuel cell with atomic resolution. The cell was studied under different oxygen pressures at elevated temperatures and polarizations by external potential control. Making use of anomalous X-ray diffraction effects at the Y and Zr K-edges allowed us to resolve the interfacial structure and chemical composition of a (100)-oriented, 9.5 mol % y...

  20. Electrochemical characteristics, thermal and chemical compatibility in the La0.7Sr0.3CoO3 electrode-γ-BIFEVOX electrolyte system

    OpenAIRE

    Buyanova, E. S.; Shafigina, R. R.; Morozova, M. V.; Emel'yanova, Yu. V.; Khisametdinova, V. V.; Zhukovskii, V. M.; Petrova, S. A.; Tarakina, N. V.

    2013-01-01

    The electrochemical characteristics and compatibility of components of the electrode-electrolyte system, where the electrolyte is chosen to be γ-BIFEVOX compositions crystallizing in a stable tetragonal phase and the cathode material is chosen to be composite electrodes of composition La 0.7Sr0.3CoO3 + Bi4V 1.7Fe0.3O11-δ, were studied. © 2013 Pleiades Publishing, Ltd.

  1. 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.

  2. Application of wet powder spraying for anode supported solid oxide fuel cell with a perovskite SrTi{sub 0.98}Nb{sub 0.02}O{sub 3-{delta}} anode

    Energy Technology Data Exchange (ETDEWEB)

    Gdaniec, Pawel; Karczewski, Jakub; Bochentyn, Beata; Gazda, Maria; Kusz, Boguslaw [Faculty of Applied Physics and Mathematics, Gdansk University of Technology, ul. Narutowicza 11/12, Gdansk, 80-233 (Poland); Molin, Sebastian; Jasinski, Piotr [Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology, ul. Narutowicza 11/12, Gdansk, 80-233 (Poland); Krupa, Andrzej [Institute of Fluid Flow Machinery, Polish Academy of Sciences, ul. Fiszera 14, Gdansk, 80-231 (Poland)

    2013-12-15

    Anode-supported solid oxide fuel cell with SrTi{sub 0.98}Nb{sub 0.02}O{sub 3-{delta}}anode, yttria-stabilized zirconia electrolyte and La(Ni{sub 0.6}Fe{sub 0.4})O{sub 3{+-}{delta}} cathode has been successfully fabricated and evaluated. Process of anode support fabrication has been presented. Wet powder spraying and high temperature sintering method have been studied and applied to deposit the thin electrolyte layer.In order to improve catalytic properties of the anode, it has been impregnated with Ni. Electrical properties of fuel cells have been measured to determine their performance. The open cell voltage of 1.08 V and maximum power density at the level of 160 mWcm {sup -2} were observed at 800 C. (copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. An intermediate-temperature solid oxide fuel cell with electrospun nanofiber cathode

    Energy Technology Data Exchange (ETDEWEB)

    Zhi, Mingjia; Lee, Shiwoo; Miller, Nicholas; Menzler, Norbert H.; Wu, Nianqiang

    2012-05-01

    Lanthanum strontium cobalt ferrite (LSCF) nanofibers have been fabricated by the electrospinning method and used as the cathode of an intermediate-temperature solid oxide fuel cell (SOFC) with yttria-stabilized zirconia (YSZ) electrolyte. The three-dimensional nanofiber network cathode has several advantages: (i) high porosity; (ii) high percolation; (iii) continuous pathway for charge transport; (iv) good thermal stability at the operating temperature; and (v) excellent scaffold for infiltration. The fuel cell with the monolithic LSCF nanofiber cathode exhibits a power density of 0.90 W cm{sup −2} at 1.9 A cm{sup −2} at 750 °C. The electrochemical performance of the fuel cell has been further improved by infiltration of 20 wt% of gadolinia-doped ceria (GDC) into the LSCF nanofiber cathode. The fuel cell with the LSCF–20% GDC composite cathode shows a power density of 1.07 W cm{sup −2} at 1.9 A cm{sup −2} at 750 °C. The results obtained show that one-dimensional nanostructures such as nanofibers hold great promise as electrode materials for intermediate-temperature SOFCs.

  4. Electrolyte creepage barrier for liquid electrolyte fuel cells

    Science.gov (United States)

    Li, Jian; Farooque, Mohammad; Yuh, Chao-Yi

    2008-01-22

    A dielectric assembly for electrically insulating a manifold or other component from a liquid electrolyte fuel cell stack wherein the dielectric assembly includes a substantially impermeable dielectric member over which electrolyte is able to flow and a barrier adjacent the dielectric member and having a porosity of less than 50% and greater than 10% so that the barrier is able to measurably absorb and chemically react with the liquid electrolyte flowing on the dielectric member to form solid products which are stable in the liquid electrolyte. In this way, the barrier inhibits flow or creepage of electrolyte from the dielectric member to the manifold or component to be electrically insulated from the fuel cell stack by the dielectric assembly.

  5. A novel stability-enhanced lithium-oxygen battery with cellulose-based composite polymer gel as the electrolyte

    International Nuclear Information System (INIS)

    Highlights: • A novel cellulose-based composite polymer gel electrolyte (PGE) membrane is prepared. • PGE exhibits excellent ionic conductivity and electrochemical stability. • PEG reduces the penetration of oxygen to lithium anode and electrolyte loss. • Non-aqueous Li/O2 battery employing PGE membrane displays good cyclic stability. - Abstract: A novel lithium-oxygen (Li-O2) battery with a polymer gel electrolyte (PGE) membrane is successfully prepared. The membrane is a blend of cellulose acetate (CA) and poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) and is fabricated using a solution casting technique followed by impregnation with lithium bis(trifluoromethane sulfonimide) (LiTFSI) solution. We demonstrate that the PGE membrane has good electrolyte uptake and shows high ionic conductivity as well as excellent thermal and electrochemical stability. A Li-O2 battery containing our PGE as the electrolyte and separator exhibits good rate capability and enhanced cycling capacity retention compared to a battery using commercial liquid electrolyte and a polyethylene (PE) separator under the same conditions. We attribute this enhanced performance to the PGE, which maybe restrain the diffusion of oxygen from the air cathode to the Li metal anode. This study may prove valuable for resolving the problem of poor cycling stability in Li-O2 batteries caused by oxygen diffusion from cathode to anode

  6. Electrolytes - Technology review

    Energy Technology Data Exchange (ETDEWEB)

    Meutzner, Falk; Ureña de Vivanco, Mateo [Institut für Experimentelle Physik, Technische Universität Bergakademie Freiberg, Leipziger Straße 23, 09596 Freiberg (Germany)

    2014-06-16

    Safety, lifetime, energy density, and costs are the key factors for battery development. This generates the need for improved cell chemistries and new, advanced battery materials. The components of an electrolyte are the solvent, in which a conducting salt and additives are dissolved. Each of them plays a specific role in the overall mechanism of a cell: the solvent provides the host medium for ionic conductivity, which originates in the conductive salt. Furthermore, additives can be used to optimize safety, performance, and cyclability. By understanding the tasks of the individual components and their optimum conditions of operation, the functionality of cells can be improved from a holistic point of view. This paper will present the most important technological features and requirements for electrolytes in lithium-ion batteries. The state-of-the-art chemistry of each component is presented, as well as different approaches for their modification. Finally, a comparison of Li-cells with lithium-based technologies currently under development is conducted.

  7. Electrolytes - Technology review

    International Nuclear Information System (INIS)

    Safety, lifetime, energy density, and costs are the key factors for battery development. This generates the need for improved cell chemistries and new, advanced battery materials. The components of an electrolyte are the solvent, in which a conducting salt and additives are dissolved. Each of them plays a specific role in the overall mechanism of a cell: the solvent provides the host medium for ionic conductivity, which originates in the conductive salt. Furthermore, additives can be used to optimize safety, performance, and cyclability. By understanding the tasks of the individual components and their optimum conditions of operation, the functionality of cells can be improved from a holistic point of view. This paper will present the most important technological features and requirements for electrolytes in lithium-ion batteries. The state-of-the-art chemistry of each component is presented, as well as different approaches for their modification. Finally, a comparison of Li-cells with lithium-based technologies currently under development is conducted

  8. Physiological aspects of fluid and electrolyte balance

    OpenAIRE

    Lobo, Dileep N.

    2003-01-01

    The intake of water and electrolytes is inseparable from feeding by natural or artificial means and careful attention to salt and water balance is a vital component of perioperative care and of nutritional support. Nutritional support with water and sodium restriction in post-intensive care patients with oedema, dilutional hypoalbuminaemia and fluid excess of 10 L, cleared oedema over 7-10 days, with a 1 g/L rise in serum albumin for every kg loss in weight. Return of gastrointestinal func...

  9. Sustainable Sulfur-rich Copolymer/Graphene Composite as Lithium-Sulfur Battery Cathode with Excellent Electrochemical Performance

    OpenAIRE

    Arnab Ghosh; Swapnil Shukla; Gaganpreet Singh Khosla; Bimlesh Lochab; Sagar Mitra

    2016-01-01

    A sulfur-rich copolymer, poly(S-r-C-a) has been synthesized via a sustainable route, showing the utility of two major industrial wastes- elemental sulfur (petroleum waste) and cardanol (agro waste), to explore its potential as cathode material for Li-S batteries. The sulfur-rich copolymer exhibited a reduction in the active material dissolution into the electrolyte and a low self-discharge rate behavior during the rest time compared to an elemental sulfur cathode, indicating the chemical conf...

  10. 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.

  11. Development of a high-performance composite cathode for LT-SOFC

    Science.gov (United States)

    Lee, Byung Wook

    Solid Oxide Fuel Cell (SOFC) has drawn considerable attention for decades due to its high efficiency and low pollution, which is made possible since chemical energy is directly converted to electrical energy through the system without combustion. However, successful commercialization of SOFC has been delayed due to its high production cost mainly related with using high cost of interconnecting materials and the other structural components required for high temperature operation. This is the reason that intermediate (IT) or low temperature (LT)-SOFC operating at 600~800°C or 650°C and below, respectively, is of particular significance because it allows the wider selection of cheaper materials such as stainless steel for interconnects and the other structural components. Also, extended lifetime and system reliability are expected due to less thermal stress through the system with reduced temperature. More rapid start-up/shut-down procedure is another advantage of lowering the operating temperatures. As a result, commercialization of SOFC will be more viable. However, there exists performance drop with reduced operating temperature due to increased polarization resistances from the electrode electrochemical reactions and decreased electrolyte conductivity. Since ohmic polarization of the electrolyte can be significantly reduced with state-of-the art thin film technology and cathode polarization has more drastic effect on total SOFC electrochemical performance than anode polarization as temperature decreases, development of the cathode with high performance operating at IT or LT range is thus essential. On the other hand, chemical stability of the cathode and its chemical compatibility with the electrolyte should also be considered for cathode development since instability and incompatibility of the cathode will also cause substantial performance loss. Based on requirements of the cathode mentioned above, in this study, several chemico-physical approaches were

  12. 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.

  13. 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

  14. Hydrolysis of and oxide solubilities in melts related to electrolytic magnesium production

    Energy Technology Data Exchange (ETDEWEB)

    Vindstad, J.E.

    1996-12-31

    It takes about 13-14 kWh to produce 1 kg magnesium metal by today`s technology, although the thermodynamic energy required is only about 6.8 kWh/kg (at 700{sup o}C). The specific energy consumption of a magnesium electrolysis cell is inversely proportional to the current efficiency, which is affected by the presence of impurities in the electrolyte. A high current efficiency requires that the cathode is well wetted by the liquid magnesium and that the latter is well wetted by the electrolyte. If the metal does not wet the cathode, and the melt not the metal, then the cathodic overvoltage and thus also the energy consumption increases. The presence of water has a detrimental effect on the electrolysis because an MgO film forms on the metal when the water reacts with the magnesium produced, thus interfering with the wetting of the cathode by the metal. It follows that a thorough knowledge of the processes going on in the hydrolysis is important for improving the energy efficiency of the magnesium production. The first part of this doctoral thesis discusses experiments on the equilibria established during hydrolysis of pure liquid MgCl{sub 2} and of a liquid NaCl-MgCl{sub 2} mixture at 730 and 675 {sup o}C. The second part deals with the effect of fluoride on the solubility of MgO in MgCl{sub 2}-containing melts. 67 refs., 35 figs., 12 tabs.

  15. Characterization of LiFePO4 cathode by addition of graphene for lithium ion batteries

    International Nuclear Information System (INIS)

    The improvement of LiFePO4 (LFP) cathode performance has been performed by addition of Graphene (LFP+Graphene). The cathode was prepared from the active material with 5 wt % graphene and 10 wt % polyvinylidene fluoride in an n-methyl pyrrolidone solvent. Another cathode material used only 5% artificial graphite for comparison (LFP+Graphite). The crystal structure, microstructure, electronic conductivity, electrochemical impedance spectroscopy (EIS) of the cathodes were characterized by X-ray diffraction, SEM, and Impedance spectroscopy, respectively. Two half cell coin batteries were assembled using a lithium metal as an anode and LiPf6 as an electrolyte, and two cathodes (LFP+Graphene) and (LFP+Graphite). Charge discharge performance of battery was characterized by Battery analyser (BTS 8). The electronic conductivity of cathode with grapheme increased of about one order magnitude compared with the only cathode with graphite, namely from 1.97E-7S/cm (LFP+Graphite) to 1.92E-6S/cm (LFP+Graphene). The charge-discharge capacity after 10th cycles of LiFePO4 with graphene decreased of about 0.68% from 114.3 mAh/g to113.1 mAh/g, while LFP with graphite decreased of about 2.84% from 110.2 mAh/g to 107.1 mAh, at 0.1C-rates. It could be concluded that the addition of graphene has increased the ionic conductivity, and improved performance of the LFP lithium ion battery, such as higher capacity and better efficiency

  16. Characterization of LiFePO4 cathode by addition of graphene for lithium ion batteries

    Science.gov (United States)

    Honggowiranto, Wagiyo; Kartini, Evvy

    2016-02-01

    The improvement of LiFePO4 (LFP) cathode performance has been performed by addition of Graphene (LFP+Graphene). The cathode was prepared from the active material with 5 wt % graphene and 10 wt % polyvinylidene fluoride in an n-methyl pyrrolidone solvent. Another cathode material used only 5% artificial graphite for comparison (LFP+Graphite). The crystal structure, microstructure, electronic conductivity, electrochemical impedance spectroscopy (EIS) of the cathodes were characterized by X-ray diffraction, SEM, and Impedance spectroscopy, respectively. Two half cell coin batteries were assembled using a lithium metal as an anode and LiPf6 as an electrolyte, and two cathodes (LFP+Graphene) and (LFP+Graphite). Charge discharge performance of battery was characterized by Battery analyser (BTS 8). The electronic conductivity of cathode with grapheme increased of about one order magnitude compared with the only cathode with graphite, namely from 1.97E-7S/cm (LFP+Graphite) to 1.92E-6S/cm (LFP+Graphene). The charge-discharge capacity after 10th cycles of LiFePO4 with graphene decreased of about 0.68% from 114.3 mAh/g to113.1 mAh/g, while LFP with graphite decreased of about 2.84% from 110.2 mAh/g to 107.1 mAh, at 0.1C-rates. It could be concluded that the addition of graphene has increased the ionic conductivity, and improved performance of the LFP lithium ion battery, such as higher capacity and better efficiency.

  17. Thin film polymeric gel electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Derzon, Dora K. (1554 Rosalba St. NE., Albuquerque, Bernalillo County, NM 87112); Arnold, Jr., Charles (3436 Tahoe, NE., Albuquerque, Bernalillo County, NM 87111); Delnick, Frank M. (9700 Fleming Rd., Dexter, MI 48130)

    1996-01-01

    Novel hybrid thin film electrolyte, based on an organonitrile solvent system, which are compositionally stable, environmentally safe, can be produced efficiently in large quantity and which, because of their high conductivities .apprxeq.10.sup.-3 .OMEGA..sup.-1 cm.sup.-1 are useful as electrolytes for rechargeable lithium batteries.

  18. Cathodic protection to control microbiologically influenced corrosion

    International Nuclear Information System (INIS)

    Information about the cathodic protection performance in environments with microbiologically influenced corrosion (MIC) effects is very fragmented and often contradictory. Not enough is known about the microbial effects on cathodic protection effectiveness, criteria, calcareous deposits, corrosion rates and possible hydrogen embrittlement of titanium and some stainless steel condenser tubes. This paper presents a review of cathodic protection systems, describes several examples of cathodic protection in environments with MIC effects and provides preliminary conclusions about cathodic protection design parameters, criteria and effectiveness in MIC environments. 30 refs

  19. Cathodes for molten-salt batteries

    Science.gov (United States)

    Argade, Shyam D.

    1993-02-01

    Viewgraphs of the discussion on cathodes for molten-salt batteries are presented. For the cathode reactions in molten-salt cells, chlorine-based and sulfur-based cathodes reactants have relatively high exchange current densities. Sulfur-based cathodes, metal sulfides, and disulfides have been extensively investigated. Primary thermal batteries of the Li-alloy/FeS2 variety have been available for a number of years. Chlorine based rechargable cathodes were investigated for the pulse power application. A brief introduction is followed by the experimental aspects of research, and the results obtained. Performance projections to the battery system level are discussed and the presentation is summarized with conclusions.

  20. Chemical and electrical properties of LSM cathodes prepared by mechanosynthesis

    Science.gov (United States)

    Moriche, R.; Marrero-López, D.; Gotor, F. J.; Sayagués, M. J.

    2014-04-01

    Mechanosynthesis of La1-xSrxMnO3 (x = 0, 0.25, 0.5, 0.75 and 1) was carried out at room temperature from stoichiometric mixtures of La2O3, Mn2O3 and SrO, obtaining monophasic powders with the perovskite structure. Physical properties of these materials and their chemical compatibility with the electrolyte yttria stabilized zirconia (YSZ), which depend strongly on the La/Sr ratio, were evaluated to corroborate availability to be implemented as cathode material in solid oxide fuel cells (SOFCs). Electrical conductivity values in air ranged between 100 and 400 S cm-1 in the temperature range of 25-850 °C. Samples presented low reactivity with YSZ in the working temperature range (600-1000 °C) maintaining the grain size small enough to preserve the catalytic activity for oxygen reduction.

  1. Oligo(ethylene glycol)-functionalized disiloxanes as electrolytes for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhengcheng; Dong, Jian; Amine, Khalil [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); West, Robert [Organosilicon Research Center, Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706 (United States)

    2010-09-15

    Functionalized disiloxane compounds were synthesized by attaching oligo(ethylene glycol) chains, -(CH{sub 2}CH{sub 2}O)-{sub n}, n = 2-7, via hydrosilation, dehydrocoupling, and nucleophilic substitution reactions and were examined as non-aqueous electrolyte solvents in lithium-ion cells. The compounds were fully characterized by {sup 1}H, {sup 13}C, and {sup 29}Si nuclear magnetic resonance (NMR) spectroscopy. Upon doping with lithium bis(oxalato)borate (LiBOB) or LiPF{sub 6}, the disiloxane electrolytes showed conductivities up to 6.2 x 10{sup -4} S cm{sup -1} at room temperature. The thermal behavior of the electrolytes was studied by differential scanning calorimetry, which revealed very low glass transition temperatures before and after LiBOB doping and much higher thermal stability compared to organic carbonate electrolytes. Cyclic voltammetry measurements showed that disiloxane-based electrolytes with 0.8 M LiBOB salt concentration are stable to 4.7 V. The LiBOB/disiloxane combinations were found to be good electrolytes for lithium-ion cells; unlike LiPF{sub 6}, LiBOB can provide a good passivation film on the graphite anode. The LiPF{sub 6}/disiloxane electrolyte was enabled in lithium-ion cells by adding 1 wt% vinyl ethylene carbonate (VEC). Full cell performance tests with LiNi{sub 0.80}Co{sub 0.15}Al{sub 0.05}O{sub 2} as the cathode and mesocarbon microbead (MCMB) graphite as the anode show stable cyclability. The results demonstrate that disiloxane-based electrolytes have considerable potential as electrolytes for use in lithium-ion batteries. (author)

  2. 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

  3. Synopsis of Cathode No.4 Activation

    International Nuclear Information System (INIS)

    The purpose of this report is to describe the activation of the fourth cathode installed in the DARHT-II Injector. Appendices have been used so that an extensive amount of data could be included without danger of obscuring important information contained in the body of the report. The cathode was a 612 M type cathode purchased from Spectra-Mat. Section II describes the handling and installation of the cathode. Section III is a narrative of the activation based on information located in the Control Room Log Book supplemented with time plots of pertinent operating parameters. Activation of the cathode was performed in accordance with the procedure listed in Appendix A. The following sections provide more details on the total pressure and constituent partial pressures in the vacuum vessel, cathode heater power/filament current, and cathode temperature

  4. Hybrid microwave oscillators with a virtual cathode

    International Nuclear Information System (INIS)

    A review is given of the developments and theoretical investigations of a fundamentally new class of microwave devices, namely, hybrid microwave oscillators with a virtual cathode, which combine the useful properties of virtual cathodes with the advantages of those traditional microwave oscillators that operate with subcritical-current beams and have a high efficiency in generating ultrarelativistic electron beams. Among such devices are the following: a hybrid diffractional microwave oscillator with a virtual cathode, a hybrid gyro-device with a virtual cathode, a hybrid beam-plasma vircator, a hybrid gyrocon with a virtual cathode, a hybrid Cherenkov oscillator with a virtual cathode, a hybrid microwave oscillator of the 'vircator + traveling-wave tube' type, an original two-beam tube with a virtual cathode, and a klystron-like vircator

  5. A Prussian Blue/Zinc Secondary Battery with a Bio-Ionic Liquid-Water Mixture as Electrolyte.

    Science.gov (United States)

    Liu, Zhen; Pulletikurthi, Giridhar; Endres, Frank

    2016-05-18

    The development of rechargeable zinc ion batteries with high capacity and high cycling stability is a great challenge in aqueous solution due to hydrogen evolution and dendritic growth of zinc. In this study, we present a zinc ion secondary battery, comprising a metallic zinc anode, a bio-ionic liquid-water electrolyte, and a nanostructured prussian blue analogue (PBA) cathode. Both the Zn anode and the PBA cathode exhibit good compatibility with the bio-ionic liquid-water electrolyte, which enables the electrochemical deposition/dissolution of zinc at the zinc anode, and reversible insertion/extraction of Zn(2+) ions at the PBA cathode. The cell exhibits a well-defined discharge voltage plateau of ∼1.1 V with a specific capacity of about 120 mAh g(-1) at a current of 10 mA g(-1) (∼0.1 C). The Zn anode shows great reversibility, and dendrite-free Zn deposits were obtained after 100 deposition/dissolution cycles. The integration of an environmentally friendly PBA cathode, a nontoxic and low-cost Zn anode, and a biodegradable ionic liquid-water electrolyte provides new perspective to develop rechargeable zinc ion batteries for various applications in electric energy storage. PMID:27119430

  6. Alternate Anodes for the Electrolytic Reduction of UO2

    Science.gov (United States)

    Merwin, Augustus; Chidambaram, Dev

    2015-01-01

    The electrolytic reduction process of UO2 employs a platinum anode and a stainless steel cathode in molten LiCl-LiO2 maintained at 973 K (700 °C). The degradation of platinum under the severely oxidizing conditions encountered during the process is an issue of concern. In this study, Inconel 600 and 718, stainless steel alloy 316, tungsten, nickel, molybdenum, and titanium, were investigated though electrochemical polarization techniques, electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy to serve as potential anode materials. Of the various materials investigated, only tungsten exhibited sufficient stability at the required potential in the molten electrolyte. Tungsten anodes were further studied in molten LiCl-LiO2 electrolyte containing 2, 4, and 6 wt pct of Li2O. In LiCl-2 wt pct Li2O tungsten was found to be sufficiently stable to both oxidation and microstructural changes and the stability is attributed to the formation of a lithium-intercalated tungsten oxide surface film. Increase in the concentration of Li2O was found to lead to accelerated corrosion of the anode, in conjunction with the formation of a peroxotungstate oxide film.

  7. Lanthanum germanate-based apatites as electrolyte for SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Marrero-Lopez, D.; Diaz-Carrasco, P.; Ramos-Barrado, J.R. [Departamento de Fisica Aplicada I, Laboratorio de Materiales y Superficies (Unidad Asociada al C.S.I.C.), Universidad de Malaga, 29071 Malaga (Spain); Pena-Martinez, J. [Instituto de Energias Renovables, Parque Tecnologico, Universidad de Castilla La Mancha, 02006 Albacete (Spain); Ruiz-Morales, J.C. [Departamento de Quimica Inorganica, Universidad de La Laguna, 38200 La Laguna, Tenerife (Spain)

    2011-02-15

    Germanate apatites with composition La{sub 10-x}Ge{sub 5.5}Al{sub 0.5}O{sub 26.75-3x/2} have been evaluated for the first time as possible electrolytes for solid oxide fuel cells (SOFCs). Different electrode materials have been considered in this study, i.e. manganite, ferrite, nickelates and cobaltite as cathode materials; and NiO-CGO composite and chromium-manganite as anodes. The chemical compatibility and electrochemical performance of these electrodes with La{sub 9.8}Ge{sub 5.5}Al{sub 0.5}O{sub 26.45} have been studied by X-ray powder diffraction (XRPD) and impedance spectroscopy. The XRPD analysis did not reveal appreciable bulk reactivity with the formation of reaction products between the germanate electrolyte and these electrodes up to 1,200 C. However, a significant cation interdiffusion was observed by energy dispersive spectroscopy (EDS) at the electrode/electrolyte interface, which leads to a significant decrease of the performance of these electrodes. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Electrolytes and thermoregulation

    Science.gov (United States)

    Nielsen, B.; Greenleaf, J. E.

    1977-01-01

    The influence of ions on temperature is studied for cases where the changes in ionic concentrations are induced by direct infusion or injection of electrolyte solutions into the cerebral ventricles or into specific areas of brain tissue; intravenous infusion or injection; eating food or drinking solutions of different ionic composition; and heat or exercise dehydration. It is shown that introduction of Na(+) and Ca(++) into the cerebral ventricles or into the venous system affects temperature regulation. It appears that the specific action of these ions is different from their osmotic effects. It is unlikely that their action is localized to the thermoregulatory centers in the brain. The infusion experiments demonstrate that the changes in sodium balance occurring during exercise and heat stress are large enough to affect sweat gland function and vasomotor activity.

  9. Polyethylene glycol dimethyl ether (PEGDME)-based electrolyte for lithium metal battery

    Science.gov (United States)

    Carbone, Lorenzo; Gobet, Mallory; Peng, Jing; Devany, Matthew; Scrosati, Bruno; Greenbaum, Steve; Hassoun, Jusef

    2015-12-01

    We propose in this work a polyethylene glycol dimethyl ether (MW 500) dissolving lithium trifluoromethansulfonate (LiCF3SO3) salt as suitable electrolyte media for a safe and efficient use of the lithium metal anode in battery. Voltammetry and galvanostatic tests reveal significant enhancement of the electrolyte characteristics, in terms of cycling life and chemical stability, by the addition of lithium nitrate (LiNO3) to the solution. Furthermore, PFG NMR measurements suggest the applicability of the electrolyte in battery in terms of ionic conductivity, lithium transference number, ionic-association degree and self-diffusion coefficient. Accordingly, the electrolyte is employed in a lithium battery using lithium iron phosphate as the selected cathode. The battery delivers a stable capacity of 150 mAh g-1 and flat working voltage of 3.5 V, thus leading to a theoretical energy density referred to the cathode of 520 Wh kg-1. This battery is considered a suitable energy storage system for advanced applications requiring both high safety and high energy density.

  10. Dependence of the corrosion behavior of aluminum alloy 7075 on the thin electrolyte layers

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, H.R. [State Key Laboratory of Environmental Adaption for Industrial Products, China National Electric Apparatus Research Institute, Guangzhou 510663 (China); Corrosion and Protection Center, University of Science and Technology Beijing, Beijing 100083 (China); Li, X.G. [Corrosion and Protection Center, University of Science and Technology Beijing, Beijing 100083 (China)], E-mail: lixiaogang99@263.net; Ma, J. [State Key Laboratory of Environmental Adaption for Industrial Products, China National Electric Apparatus Research Institute, Guangzhou 510663 (China); Dong, C.F. [Corrosion and Protection Center, University of Science and Technology Beijing, Beijing 100083 (China); Huang, Y.Z. [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom)

    2009-05-15

    The corrosion behavior of aluminum alloy 7075-T6 dependent of the thin electrolyte layers in 1 M sodium sulfate solution has been investigated using cathodic polarization, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The oxygen reduction current is measured to be maximum at -1.1 V by cathodic polarization test when the thickness of the electrolyte layer is 110 {mu}m. The EIS results show that the corrosion rate increases with the increase of the immersing time independent of thickness of the electrolyte layer although 110 {mu}m thick electrolyte layer produces the largest corrosion rate over the immersing time between 0 h and 96 h. However, with the longer immersing time, corrosion rate of the sample in bulk solution becomes higher. This result can be explained that the diffusion of the corrosion product and the metal ions from the electrode in the case of the thicker layer is easier. SEM morphologies reveal that corrosion products on the surface of the samples are distributed unhomogenously, with their amount near edges being more than the center area. In addition, XPS analysis demonstrates that corrosion products are mainly composed of Al(OH){sub 3} and Al{sub 2}(SO{sub 4}){sub 3}.

  11. Influence of anode pore forming additives on the densification of supported BaCe0.7Ta0.1Y0.2O3−δ electrolyte membranes based on a solid state reaction

    NARCIS (Netherlands)

    Bi, Lei; Fang, Shumin; Tao, Zetian; Zhang, Shangquan; Peng, Ranran; Liu, Wei

    2009-01-01

    We describe a solid state reaction for the preparation of both NiO–BaCe0.7Ta0.1Y0.2O3−δ anode substrates and BaCe0.7Ta0.1Y0.2O3−δ (BCTY10) electrolyte membranes on porous NiO–BCTY10 anode substrates. The amounts of the pore forming additive in the substrates showed a significant influence on the den

  12. 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.

  13. Investigation of electrolyte wetting in lithium ion batteries: Effects of electrode pore structures and solution

    Science.gov (United States)

    Sheng, Yangping

    Beside natural source energy carriers such as petroleum, coal and natural gas, the lithium ion battery is a promising man-made energy carrier for the future. This is a similar process evolved from horse-powered era to engine driven age. There are still a lot of challenges ahead like low energy density, low rate performance, aging problems, high cost and safety etc. In lithium ion batteries, investigation about manufacturing process is as important as the development of material. The manufacturing of lithium ion battery, including production process (slurry making, coating, drying etc.), and post-production (slitting, calendering etc.) is also complicated and critical to the overall performance of the battery. It includes matching the capacity of anode and cathode materials, trial-and-error investigation of thickness, porosity, active material and additive loading, detailed microscopic models to understand, optimize, and design these systems by changing one or a few parameters at a time. In the manufacturing, one of the most important principles is to ensure good wetting properties between porous solid electrodes and liquid electrolyte. Besides the material surface properties, it is the process of electrolyte transporting to fill the pores in the electrode after injection is less noticed in academic, where only 2-3 drops of electrolyte are needed for lab coin cell level. In industry, the importance of electrolyte transport is well known and it is considered as part of electrolyte wetting (or initial wetting in some situations). In consideration of practical usage term, electrolyte wetting is adopted to use in this dissertation for electrolyte transporting process, although the surface chemistry about wetting is not covered. An in-depth investigation about electrolyte wetting is still missing, although it has significant effects in manufacturing. The electrolyte wetting is determined by properties of electrolyte and electrode microstructure. Currently, only viscosity

  14. Enhanced photocurrent generation in bacteriorhodopsin based bio-sensitized solar cells using gel electrolyte.

    Science.gov (United States)

    Chellamuthu, Jeganathan; Nagaraj, Pavithra; Chidambaram, Sabari Girisun; Sambandam, Anandan; Muthupandian, Ashokkumar

    2016-09-01

    High purity light sensitive photoactive protein Bacteriorhodopsin (BR) was isolated successfully via a simple two phase extraction technique (ATPS) as an alternate method for the tedious sucrose gradient ultracentrifugation procedure (SGU). Bio sensitized solar cells (BSSCs) were fabricated by the integration of BR into TiO2 (photo anode) with acetamide based gel electrolytes and platinum (photo cathode) as a counter electrode. The structural and photoelectrical behaviours of BR and BSSCs were analyzed by Atomic Force Microscopy, Raman spectroscopy, photocurrent and photovoltage (IV) measurement and electrochemical impedance spectroscopy. The short circuit photocurrent (Jsc) and photoelectric conversion efficiency (η) of acetamide based gel electrolyte (AG) (1.08mAcm(-2), 0.49%) are twice higher than that of traditional triiodide based liquid electrolyte (LE) (0.62mAcm(-2), 0.19%). Also, quasi-Fermi level and lifetime of photogenerated electrons in acetamide based gel electrolyte is about four times higher than that observed in traditional triiodide redox electrolyte. A comparison of the observed results with similar BSSCs made of other natural photoactive protein systems shows that BR as sensitizer has better photovoltaic performance. The enhanced photocurrent generation of the BSSC constructed in our study could be due to the interaction of BR with acetamide based modified poly(ethylene)oxide (PEO) gel electrolyte. PMID:27380296

  15. Preparation and characterization of nanocomposite polymer electrolytes poly(vinylidone fluoride)/nanoclay

    Energy Technology Data Exchange (ETDEWEB)

    Rahmawati, Suci A.; Sulistyaningsih,; Putro, Alviansyah Z. A.; Widyanto, Nugroho F.; Jumari, Arif; Purwanto, Agus; Dyartanti, Endah R., E-mail: endahrd@uns.ac.id [Research Group of Battery & Advanced Material, Department of Chemical Engineering, Sebelas Maret University, Jl. Ir. Sutami 36 A Kentingan, Surakarta Indonesia 57126 (Indonesia)

    2016-02-08

    Polymer electrolytes are defined as semi solid electrolytes used as separator in lithium ion battery. Separator used as medium for transfer ions and to prevent electrical short circuits in battery cells. To obtain the optimal battery performance, separator with high porosity and electrolyte uptake is required. This can reduce the resistance in the transfer of ions between cathode and anode. The main objective of this work is to investigate the impact of different solvent (Dimethyl acetamide (DMAc), N-methyl-2-pyrrolidone (NMP) and dimethyl formamide (DMF)), pore forming agent poly(vinylpyrolidone) (PVP) and nanoclay as filler in addition of membrane using phase inversion method on the morphology, porosity, electrolyte uptake and degree of crystallinity. The membrane was prepared by the phase inversion method by adding PVP and Nanoclay using different solvents. The phase inversion method was prepared by dissolving Nanoclay and PVP in solvent for 1-2 hours, and then add the PVDF with stirring for 4 hours at 60°C. The membranes were characterized by porosity test, electrolyte uptake test, scanning electron microscope (SEM), and X-ray diffraction (XRD). The results showed that DMAc as solvent gives the highest value of porosity and electrolyte uptake. The addition of nanoclay and PVP enlarge the size of the pores and reduce the degree of crystallinity. So, the usage of DMAc as solvent is better than NMP or DMF.

  16. Hybrid Lithium-Sulfur Batteries with a Solid Electrolyte Membrane and Lithium Polysulfide Catholyte.

    Science.gov (United States)

    Yu, Xingwen; Bi, Zhonghe; Zhao, Feng; Manthiram, Arumugam

    2015-08-01

    Lithium-sulfur (Li-S) batteries are receiving great attention as the most promising next-generation power source with significantly high charge-storage capacity. However, the implementation of Li-S batteries is hampered by a critical challenge because of the soluble nature of the intermediate polysulfide species in the liquid electrolyte. The use of traditional porous separators unavoidably allows the migration of the dissolved polysulfide species from the cathode to the lithium-metal anode and results in continuous loss of capacity. In this study, a LiSICON (lithium super ionic conductor) solid membrane is used as a cation-selective electrolyte for lithium-polysulfide (Li-PS) batteries to suppress the polysulfide diffusion. Ionic conductivity issue at the lithium metal/solid electrolyte interface is successfully addressed by insertion of a "soft", liquid-electrolyte integrated polypropylene interlayer. The solid LiSICON lithium-ion conductor maintains stable ionic conductivity during the electrochemical cycling of the cells. The Li-PS battery system with a hybrid solid/liquid electrolyte exhibits significantly enhanced cyclability relative to the cells with the traditional liquid-electrolyte integrated porous separator. PMID:26161547

  17. Multi-Field Coupling Mechanism of Electrolytic In-process Dressing- Ultrasonic Honing System

    Directory of Open Access Journals (Sweden)

    Jicai Kuai

    2013-07-01

    Full Text Available This paper proposes the ELID (Electrolytic in Process Dressing ultrasonic honing system, and conducts simulation for the solution - acoustic coupling mechanism of electrolyte between the anion and cathode of ELID ultrasonic honing system. Meanwhile, a comparative experiment is carried out for the ultrasonic honing and ordinary honing. The simulation results show that there is no obvious increase of the coupling speed of the system’s electrolyte, but the rapid change of local speed, which will accelerate the electrolyte renewal around the electrode, thereby intensifying the mass transfer of reactive ion of the electrochemical double layer, increasing the updating speed of ion concentration and speeding up the electrode reaction process; the intense variations of coupling pressure further enhances the updating speed of the electrolyte; Then the electrolytic parameters, ultrasound parameters and honing parameters obtained by simulation are respectively used to conduct experiments of ELID-ultrasound honing, ultrasound honing and traditional honing for ZrO2 ceramic. The comparative experiment results show that the machining accuracy of ELID-ultrasonic honing is 10 times of the traditional honing and twice of the ultrasonic honing; the new acoustic system adopted in ELID-ultrasound honing system reduces the amplitude, so the processing efficiency increase is not significant. This ELID-ultrasonic honing system is more suitable for the ultra-precision honing of certain difficult-to-cut materials.  

  18. Enhanced Cycling Stability of Rechargeable Li-O2 Batteries Using High Concentration Electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Bin; Xu, Wu; Yan, Pengfei; Sun, Xiuliang; Bowden, Mark E.; Read, Jeffrey; Qian, Jiangfeng; Mei, Donghai; Wang, Chong M.; Zhang, Jiguang

    2016-01-26

    The electrolyte stability against reactive reduced-oxygen species is crucial for the development of rechargeable Li-O2 batteries. In this work, we systematically investigated the effect of lithium salt concentration in 1,2-dimethoxyethane (DME)-based electrolytes on the cycling stability of Li-O2 batteries. Cells with high concentration electrolyte illustrate largely enhanced cycling stability under both the full discharge/charge (2.0-4.5 V vs. Li/Li+) and the capacity limited (at 1,000 mAh g-1) conditions. These cells also exhibit much less reaction-residual on the charged air electrode surface, and much less corrosion to the Li metal anode. The density functional theory calculations are conducted on the molecular orbital energies of the electrolyte components and the Gibbs activation barriers for superoxide radical anion to attack DME solvent and Li+-(DME)n solvates. In a highly concentrated electrolyte, all DME molecules have been coordinated with salt and the C-H bond scission of a DME molecule becomes more difficult. Therefore, the decomposition of highly concentrated electrolyte in a Li-O2 battery can be mitigated and both air-cathodes and Li-metal anodes exhibits much better reversibility. As a results, the cyclability of Li-O2 can be largely improved.

  19. Modeling Joule Heating Effect on Lunar O2 Generation via Electrolytic Reduction.

    Science.gov (United States)

    Dominquez, Jesus; Poizeau, Sophie; Sibille, Laurent

    2009-01-01

    Kennedy Space Center is leading research work on lunar O2 generation via electrolytic reduction of regolith; the metal oxide present in the regolith is dissociated in oxygen anions and metal cations leading to the generation of gaseous oxygen at the anode and liquid metal at the cathode. Electrical resistance of molten regolith is high, leading to heating of the melt when electrical current is applied between the electrodes (Joule heating). The authors have developed a 3D model using a rigorous approach for two coupled physics (thermal and electrical potential) to not only study the effect of Joule heating on temperature distribution throughout the molten regolith but also to evaluate and optimize the design of the electrolytic cells. This paper presents the results of the thermal analysis performed on the model and used to validate the design of the electrolytic cell.

  20. The Mechanism of Electropolishing of Niobium in Hydrofluoric-Sulfuric Acid Electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Hui; Corcoran, Sean; Reece, Charles; Kelley, Michael

    2008-07-01

    Niobium surfaces are commonly electropolished in an effort to obtain optimal smoothness for high-field superconducting radio-frequency cavity applications. We report the use of controlled electrochemical analysis techniques to characterize electropolishing of Nb in a sulfuric and hydrofluoric acid electrolyte. Through the use of a reference electrode, we are able to clearly distinguish the anode and cathode polarization potentials as well as the electrolyte voltage drop, which together sum to the applied power supply voltage. We then identify the temperature and HF concentration dependence of each potential. We also report the use of electrochemical impedance spectroscopy (EIS) on this system. EIS results are consistent with the compact salt film mechanism for niobium electropolishing (EP) in this electrolyte and are not consistent with either the porous salt film or the absorbate-acceptor mechanism. Microscopic understanding of the basic Nb EP mechanism is expected to provide an appro

  1. Countermeasures for electrolytic corrosion - Part I: Traditional methods and their problems

    International Nuclear Information System (INIS)

    When an underground pipeline runs parallel with DC-powered railways, it suffers from electrolytic corrosion caused by the stray current leaked from the railway negative returns. Perforation due to the electrolytic corrosion may bring about large-scale accidents even in cathodically protected systems. Traditionally, bonding methods such as direct drainage, polarized drainage and forced drainage have been used in order to mitigate the damage on pipelines. In particular, the forced drainage method is widely adopted in Korea. In this paper, we report the real-time measurement data of the pipe-to-soil potential variation in the presence and absence of the IR compensation. The drainage current variation was also measured using the Stray Current Logger developed. By analysing them, the problems of current countermeasures for electrolytic corrosion are discussed. (authors)

  2. 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.

  3. Advanced Measurement and Modeling Techniques for Improved SOFC Cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Stuart Adler; L. Dunyushkina; S. Huff; Y. Lu; J. Wilson

    2006-12-31

    The goal of this project was to develop an improved understanding of factors governing performance and degradation of mixed-conducting SOFC cathodes. Two new diagnostic tools were developed to help achieve this goal: (1) microelectrode half-cells for improved isolation of cathode impedance on thin electrolytes, and (2) nonlinear electrochemical impedance spectroscopy (NLEIS), a variant of traditional impedance that allows workers to probe nonlinear rates as a function of frequency. After reporting on the development and efficacy of these tools, this document reports on the use of these and other tools to better understand performance and degradation of cathodes based on the mixed conductor La{sub 1-x}Sr{sub x}CoO{sub 3-{delta}} (LSC) on gadolinia or samaria-doped ceria (GDC or SDC). We describe the use of NLEIS to measure O{sub 2} exchange on thin-film LSC electrodes, and show that O{sub 2} exchange is most likely governed by dissociative adsorption. We also describe parametric studies of porous LSC electrodes using impedance and NLEIS. Our results suggest that O{sub 2} exchange and ion transport co-limit performance under most relevant conditions, but it is O{sub 2} exchange that is most sensitive to processing, and subject to the greatest degradation and sample-to-sample variation. We recommend further work that focuses on electrodes of well-defined or characterized geometry, and probes the details of surface structure, composition, and impurities. Parallel work on primarily electronic conductors (LSM) would also be of benefit to developers, and to improved understanding of surface vs. bulk diffusion.

  4. Effect of zirconium and niobium on process of uranium dioxide cathodic deposition in molten alkali metal chlorides

    International Nuclear Information System (INIS)

    The process of electrocrystallization of uranium dioxide from molten chloride electrolytes in the presence of tetravalent and pentavalent niobium has been studied by voltammetric method. it has been ascertained that tetravalent zirconium interacts according o exchange mechanism with uranium dioxide with formation of solid solutions (1-x)UO2·xZrO2. Pentavalent niobium is reduced to tetravalent one on the cathode with formation of solid solution (1-y)UO2·NbO2. In simultaneous presence in electrolyte of Zr(4) and Nb(5) ternary solid solutions (1-y-x)UO2·xZrO2·NbO2 are formed on the cathode. 12 refs., 4 figs

  5. Crystallization behavior of MgB{sub 2} films fabricated on copper cathodes via electrochemical technique

    Energy Technology Data Exchange (ETDEWEB)

    Yang Huazhe, E-mail: hzyang@mail.cmu.edu.cn [Department of Biophysics, College of Basic Medical Science, China Medical University, Shenyang, Liaoning 110001 (China); Sun Xiaguang; Yu Xiaoming [Institute of Materials Physics and Chemistry, School of Sciences, Northeastern University, Shenyang 110819 (China); Qi Yang, E-mail: qiyang@imp.neu.edu.cn [Institute of Materials Physics and Chemistry, School of Sciences, Northeastern University, Shenyang 110819 (China)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer A modified electrolysis cell was devised to prepare MgB{sub 2} films on copper cathode. Black-Right-Pointing-Pointer Crystallization behavior of MgB{sub 2} phase of films was investigated. Black-Right-Pointing-Pointer Phase transformation of Mg-B and Mg-Cu compound was discussed. Black-Right-Pointing-Pointer Mechanism for the dendritic growth of MgB{sub 2} phase was proposed. - Abstract: An electrochemical technique was devised and settled to prepare MgB{sub 2} films on copper cathodes in MgCl{sub 2}-Mg(BO{sub 2}){sub 2}-NaCl-KCl molten salts. X-ray diffraction and scanning probe microscopy were adopted to investigate the phase composition and elements distribution of sample. R-T curve of film was monitored through standard four-probe method. Transmission electron microscope and scanning electron microscope analysis were chosen to investigate the crystallization behavior and morphology of the films at different electrolytic temperatures. The results indicated that MgB{sub 2} films were successfully fabricated on the copper cathodes, and the optimal electrolytic temperature was 601 Degree-Sign C. It was presumed that the non-conducting MgO impurities hindered continuous growth of MgB{sub 2} grain, which may result in dendritic growth of MgB{sub 2} grain.

  6. Performance of MnO2 Crystallographic Phases in Rechargeable Lithium-Air Oxygen Cathode

    Science.gov (United States)

    Oloniyo, Olubukun; Kumar, Senthil; Scott, Keith

    2012-05-01

    Manganese dioxide (MnO2) has been shown to be effective for improving the efficiency of cathodes in lithium-air cells. Different crystallographic phases including α-, β-, and γ-MnO2 nanowires, α-MnO2 nanospheres, and α-MnO2 nanowires on carbon ( α-MnO2/C) were synthesized using the hydrothermal method. Their physical properties were examined using x-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area measurements, and scanning electron microscopy (SEM) and found to be in agreement with the literature. Electrochemical properties of the synthesized catalyst particles were investigated by fabricating cathodes and testing them in a lithium-air cell with lithium hexafluorophosphate in propylene carbonate (LiPF6/PC) and tetra(ethylene glycol)dimethyl ether (LiTFSi/TEGDME) electrolytes. α-MnO2 had the highest discharge capacity in the LiTFSi/TEGDME electrolyte (2500 mAh/g), whilst α-MnO2/C in LiPF6/PC showed a significantly higher discharge capacity of 11,000 mAh/g based on total mass of the catalytic cathode. However, the latter showed poor capacity retention compared with γ-MnO2 nanowires, which was stable for up to 30 cycles. The reported discharge capacity is higher than recorded in previous studies on lithium-air cells.

  7. A high performance cathode for proton conducting solid oxide fuel cells

    KAUST Repository

    Wang, Zhiquan

    2015-01-01

    Intermediate temperature solid-oxide fuel cells (IT-SOFCs)), as one of the energy conversion devices, have attracted worldwide interest for their great fuel efficiency, low air pollution, much reduced cost and excellent longtime stability. In the intermediate temperature range (500-700°C), SOFCs based on proton conducting electrolytes (PSOFCs) display unique advantages over those based on oxygen ion conducting electrolytes. A key obstacle to the practical operation of past P-SOFCs is the poor stability of the traditionally used composite cathode materials in the steam-containing atmosphere and their low contribution to proton conduction. Here we report the identification of a new Ruddlesden-Popper-type oxide Sr3Fe2O7-δ that meets the requirements for much improved long-term stability and shows a superior single-cell performance. With a Sr3Fe2O7-δ-5 wt% BaZr0.3Ce0.5Y0.2O3-δ cathode, the P-SOFC exhibits high power densities (683 and 583 mW cm-2 at 700°C and 650°C, respectively) when operated with humidified hydrogen as the fuel and air as the cathode gas. More importantly, no decay in discharging was observed within a 100 hour test. © The Royal Society of Chemistry 2015.

  8. The Electrochemical Reduction of Chromium Sesquioxide in Molten Calcium Chloride under Cathodic Potential Control

    Science.gov (United States)

    Schwandt, Carsten; Fray, Derek J.

    2007-11-01

    Electrochemical polarization and reduction experiments are reported which were performed with a three-terminal cell and a molten salt electrolyte consisting of calcium chloride with additions of calcium oxide. Employing a metal cathode, a graphite anode and a pseudo-reference electrode also made from graphite, polarization measurements were carried out with the aim to validate the performance of the pseudo-reference electrode and to assess the stability of the electrolyte. Using a chromium sesquioxide cathode in conjunction with a graphite anode and a graphite pseudo-reference electrode, electrochemical reduction experiments were conducted under potentiostatic control. The key results are: a graphite pseudo-reference electrode has been shown to be appropriate in the present type of molten salt electrochemical experiments that take place on a time scale of many hours; the conversion of chromium oxide into chromium metal has been accomplished under cathodic potential control and in the absence of calcium metal deposition; a significant amount of calcium oxide in the calcium chloride has been found necessary to preclude anodic chlorine formation throughout the entire experiment; a considerable overpotential has been identified at the anode.

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

    International Nuclear Information System (INIS)

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

  10. Organic electrolytes for sodium batteries

    Science.gov (United States)

    Vestergaard, B.

    1992-09-01

    A summary of earlier given status reports in connection with the project on organic electrolytes for sodium batteries is presented. The aim of the investigations was to develop new room temperature molten salts electrolytes mainly with radical substituted heterocyclic organic chlorides mixed with aluminum chloride. The new electrolytes should have an ionic conductivity comparable with MEIC1:AlCl3 or better. A computer model program MOPAC (Molecular Orbital Package) was to be included to calculate theoretically reduction potentials for a variety of organic cations. Furthermore, MOPAC could be utilized to predict the electron densities, and then give a prediction of the stability of the organic cation.

  11. Effect of binder polymer structures used in composite cathodes on interfacial charge transfer processes in lithium polymer batteries

    Energy Technology Data Exchange (ETDEWEB)

    Seki, Shiro; Tabata, Seiichiro [Yokohama National University (Japan). Dept. of Chemistry and Biotechnology; Matsui, Shohei [DAISO Co. Ltd., Amagasaki (Japan); Watanabe, Masayoshi [Yokohama National University (Japan). Dept. of Chemistry and Biotechnology; CREST JST, Yokohama (Japan)

    2004-11-30

    The effect of binder polymer structures used in composite cathodes on the interfacial charge transfer processes in lithium polymer batteries (LPB) has been studied in detail. A cross-linked comb-copolymer, consisting of ethylene oxide (EO), 2-(2-methoxyethoxy)ethyl glycidyl ether (MEEGE), and allyl glycidyl ether (AGE), was used as a solid polymer electrolyte (SPE). LiCoO{sub 2} composite cathodes were fabricated using binder comb-copolymers, consisting of EO and MEEGE with different compositions. Ionic conductivity of the SPE, and the interfacial charge transfer processes between the SPE and metallic lithium and between the SPE and the composite cathode at several cathode potentials versus Li/Li{sup +}, were electrochemically explored. With increasing MEEGE composition in the binder copolymers, the interfacial resistances between the SPE and the composite cathode appreciably decreased. As the result, discharge capacity of the LPB also enhanced with increasing the MEEGE composition. The introduction of the branched-side-chains to the polymer backbone to the binder polymers for the composite cathodes caused to facilitate the interfacial charge transport processes, while the introduction had also been found to be very effective in terms of the enhancement of ionic conductivity of SPE. (author)

  12. Effect of binder polymer structures used in composite cathodes on interfacial charge transfer processes in lithium polymer batteries

    International Nuclear Information System (INIS)

    The effect of binder polymer structures used in composite cathodes on the interfacial charge transfer processes in lithium polymer batteries (LPB) has been studied in detail. A cross-linked comb-copolymer, consisting of ethylene oxide (EO), 2-(2-methoxyethoxy)ethyl glycidyl ether (MEEGE), and allyl glycidyl ether (AGE), was used as a solid polymer electrolyte (SPE). LiCoO2 composite cathodes were fabricated using binder comb-copolymers, consisting of EO and MEEGE with different compositions. Ionic conductivity of the SPE, and the interfacial charge transfer processes between the SPE and metallic lithium and between the SPE and the composite cathode at several cathode potentials versus Li/Li+, were electrochemically explored. With increasing MEEGE composition in the binder copolymers, the interfacial resistances between the SPE and the composite cathode appreciably decreased. As the result, discharge capacity of the LPB also enhanced with increasing the MEEGE composition. The introduction of the branched-side-chains to the polymer backbone to the binder polymers for the composite cathodes caused to facilitate the interfacial charge transport processes, while the introduction had also been found to be very effective in terms of the enhancement of ionic conductivity of SPE

  13. Grain Boundary Effects in Solid Oxide Electrolytes

    Science.gov (United States)

    Ng, Mai

    Ion conducting ceramics are essential in applications such as solid oxide fuel cells and oxygen sensors. Traditional 8 mol% yttria-stabilized zirconia (8YSZ) solid oxide electrolytes operate at high temperatures (850°C-1000°C) to achieve high ionic conductivity (> 0.1 Scm-1 at 1000°C) by oxygen ion diffusion via vacancies. Operation at such temperatures requires high temperature electrode materials and shortens device lifetime due to interdiffusion and reactions at electrode/electrolyte interfaces. These concerns drive research in current systems and alternative materials to improve ionic conductivity at reduced operating temperatures. This research considers how grain size and grain boundary phases affect three electrolyte materials with different ion diffusion mechanisms. First, the conductivity of ultra-fine grained two-step sintered and large grained conventional sintered 8YSZ are compared to determine if enhanced ionic conductivity occurs supporting the theory that ion blocking impurities in grain boundaries are diluted with decreasing grain size. Second, apatite-type lanthanide silicates (Ln9.33(SiO4)6O2) which exhibit anisotropic interstitial oxygen diffusion at intermediate temperatures (400°C-800°C) are studied to determine whether grain boundaries detrimentally affect conductivity. Lastly, proton conducting La-monazite (LaPO4) is evaluated to determine the role of Sr-doping (up to 10% substitution of La with Sr) on grain size and conductivity as well as the effect of sintering in air or water vapor on the formation of intergranular phases rich in Sr and P. This research investigates grain boundary effects in three solid oxide electrolyte materials with the goal of understanding how grain boundaries affect ionic conductivity and the atomistic behavior governing these different diffusion mechanisms.

  14. The fractal nature of vacuum arc cathode spots

    Energy Technology Data Exchange (ETDEWEB)

    Anders, Andre

    2005-05-27

    Cathode spot phenomena show many features of fractals, for example self-similar patterns in the emitted light and arc erosion traces. Although there have been hints on the fractal nature of cathode spots in the literature, the fractal approach to spot interpretation is underutilized. In this work, a brief review of spot properties is given, touching the differences between spot type 1 (on cathodes surfaces with dielectric layers) and spot type 2 (on metallic, clean surfaces) as well as the known spot fragment or cell structure. The basic properties of self-similarity, power laws, random colored noise, and fractals are introduced. Several points of evidence for the fractal nature of spots are provided. Specifically power laws are identified as signature of fractal properties, such as spectral power of noisy arc parameters (ion current, arc voltage, etc) obtained by fast Fourier transform. It is shown that fractal properties can be observed down to the cutoff by measurement resolution or occurrence of elementary steps in physical processes. Random walk models of cathode spot motion are well established: they go asymptotically to Brownian motion for infinitesimal step width. The power spectrum of the arc voltage noise falls as 1/f {sup 2}, where f is frequency, supporting a fractal spot model associated with Brownian motion.

  15. Organotrisulfide: A High Capacity Cathode Material for Rechargeable Lithium Batteries.

    Science.gov (United States)

    Wu, Min; Cui, Yi; Bhargav, Amruth; Losovyj, Yaroslav; Siegel, Amanda; Agarwal, Mangilal; Ma, Ying; Fu, Yongzhu

    2016-08-16

    An organotrisulfide (RSSSR, R is an organic group) has three sulfur atoms which could be involved in multi-electron reduction reactions; therefore it is a promising electrode material for batteries. Herein, we use dimethyl trisulfide (DMTS) as a model compound to study its redox reactions in rechargeable lithium batteries. With the aid of XRD, XPS, and GC-MS analysis, we confirm DMTS could undergo almost a 4 e(-) reduction process in a complete discharge to 1.0 V. The discharge products are primarily LiSCH3 and Li2 S. The lithium cell with DMTS catholyte delivers an initial specific capacity of 720 mAh g(-1) DMTS and retains 82 % of the capacity over 50 cycles at C/10 rate. When the electrolyte/DMTS ratio is 3:1 mL g(-1) , the reversible specific energy for the cell including electrolyte can be 229 Wh kg(-1) . This study shows organotrisulfide is a promising high-capacity cathode material for high-energy rechargeable lithium batteries. PMID:27411083

  16. A study of surface film formation on LiNi0.8Co0.15Al0.05O2 cathodes u sing attenuated total reflection infrared spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Song, S.-W.; Zhuang, G.V.; Ross Jr., P.N.

    2004-01-19

    The surface films formed on commercial LiNi0.8Co0.15Al0.05O2 cathodes (ATD Gen2) charged from 3.75V to 4.2V vs. Li/Li+ in EC:DEC - 1M LiPF6 were analyzed using ex-situ Fourier transform infrared spectroscopy (FTIR) with the attenuated total reflection (ATR) technique. A surface layer of Li2CO3 is present on the virgin cathode, probably from reaction of the active material with air during the cathode preparation procedure. The Li2CO3 layer disappeared even after soaking in the electrolyte, indicating that the layer dissolved into the electrolyte possibly even before potential cycling of the electrode. IR features only from the binder (PVdF) and a trace of polyamide from the Al current collector were observed on the surfaces of cathodes charged to below 4.2 V, i.e., no surface species from electrolyte oxidation. Some new IR features were, however, found on the cathode charged to 4.2 V and higher. An electrolyte oxidation product was observed that appeared to contain dicarbonyl anhydride and (poly)ester functionalities. The reaction appears to be an indirect electrochemical oxidation with overcharging (removal of > 0.6 Li ions) destabilizing oxygen in the oxide lattice resulting in oxygen transfer to the solvent molecules.

  17. Lithium-ion-based solid electrolyte tuning of the carrier density in graphene

    Science.gov (United States)

    Zhao, Jialin; Wang, Meng; Li, Hui; Zhang, Xuefu; You, Lixing; Qiao, Shan; Gao, Bo; Xie, Xiaoming; Jiang, Mianheng

    2016-01-01

    We have developed a technique to tune the carrier density in graphene using a lithium-ion-based solid electrolyte. We demonstrate that the solid electrolyte can be used as both a substrate to support graphene and a back gate. It can induce a change in the carrier density as large as 1 × 1014 cm−2, which is much larger than that induced with oxide-film dielectrics, and it is comparable with that induced by liquid electrolytes. Gate modulation of the carrier density is still visible at 150 K, which is lower than the glass transition temperature of most liquid gating electrolytes. PMID:27698413

  18. Investigations on the electrochemical decomposition of the electrolyte additive vinylene carbonate in Li metal half cells and lithium ion full cells

    Science.gov (United States)

    Qian, Yunxian; Schultz, Carola; Niehoff, Philip; Schwieters, Timo; Nowak, Sascha; Schappacher, Falko M.; Winter, Martin

    2016-11-01

    In this study, the decomposition of vinylene carbonate (VC) additive and its effect on the aging behavior is investigated in Li metal half cells and lithium ion full cells. Four electrolyte systems, the reference electrolyte with three VC additive amounts, i.e., 1, 5 and 10 vol% are examined with commercial LiNi1/3Mn1/3Co1/3O2 (NMC 111) cathode material and mesophase carbon microbeads (MCMB) anode material. The thickness changes of the cathode electrolyte interphase (CEI) and of the solid electrolyte interphase (SEI) after 5 constant current cycles at 0.1C and 200 constant current/constant voltage (potential) cycles at 1C are investigated for cells containing different amounts of VC. With the help of X-ray photoelectron spectroscopy (XPS) and high-performance liquid chromatography (HPLC), a correlation between CEI thickness change and electrolyte decomposition is figured out. The addition of VC leads to a thin CEI layer and a high capacity retention in a lithium metal half cell. A strong dependence of the performance on the VC concentration is found for half cells that results from the continuous consumption of electrolyte and the electrolyte additive at the Li metal counter electrode. In contrast, for full cells, even 1 vol% of VC helps to form both a stable CEI and SEI, while a larger amount of VC increases the CEI thickness, electric contact loss and the internal resistance.

  19. Non-aqueous electrolytes for electrochemical cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhengcheng; Dong, Jian; Amine, Khalil

    2016-06-14

    An electrolyte electrochemical device includes an anodic material and an electrolyte, the electrolyte including an organosilicon solvent, a salt, and a hybrid additiving having a first and a second compound, the hybrid additive configured to form a solid electrolyte interphase film on the anodic material upon application of a potential to the electrochemical device.

  20. Electrocatalysis in Water Electrolysis with Solid Polymer Electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Rasten, Egil

    2001-10-01

    Development and optimization of the electrodes in a water electrolysis system using a polymer membrane as electrolyte have been carried out in this work. A cell voltage of 1.59 V (energy consumption of about 3.8 kWh/Nm{sub 3} H{sub 2}) has been obtained at practical operation conditions of the electrolysis cell (10 kA . m2, 90{sup o}C) using a total noble metal loading of less than 2.4 mg.cm{sub 2} and a Nafion -115 membrane. It is further shown that a cell voltage of less than 1.5 V is possible at the same conditions by combination of the best electrodes obtained in this work. The most important limitation of the electrolysis system using polymer membrane as electrolyte has proven to be the electrical conductivity of the catalysts due to the porous backing/current collector system, which increases the length of the current path and decreases the cross section compared to the apparent one. A careful compromise must therefore be obtained between electrical conductivity and active surface area, which can be tailored by preparation and annealing conditions of the metal oxide catalysts. Anode catalysts of different properties have been developed. The mixed oxide of Ir-Ta (85 mole% Ir) was found to exhibit highest voltage efficiency at a current density of 10 kA.m{sub 2} or below, whereas the mixed oxide of Ir and Ru (60-80 mole% Ir) was found to give the highest voltage efficiency for current densities of above 10 kA.m{sub 2}. Pt on carbon particles, was found to be less suitable as cathode catalyst in water electrolysis. The large carbon particles introduced an unnecessary porosity into the catalytic layer, which resulted in a high ohmic drop. Much better voltage efficiency was obtained by using Pt-black as cathode catalyst, which showed a far better electrical conductivity. Ru-oxide as cathode catalyst in water electrolysis systems using a polymer electrolyte was not found to be of particular interest due to insufficient electrochemical activity and too low

  1. Rapid self-start of polymer electrolyte fuel cell stacks from subfreezing temperatures

    Science.gov (United States)

    Ahluwalia, R. K.; Wang, X.

    Polymer electrolyte fuel cell (PEFC) systems for light-duty vehicles must be able to start unassisted and rapidly from temperatures below -20 °C. Managing buildup of ice within the porous cathode catalyst and electrode structure is the key to self-starting a PEFC stack from subfreezing temperatures. The stack temperature must be raised above the melting point of ice before the ice completely covers the cathode catalyst and shuts down the electrochemical reaction. For rapid and robust self-start it is desirable to operate the stack near the short-circuit conditions. This mode of operation maximizes hydrogen utilization, favors production of waste heat that is absorbed by the stack, and delays complete loss of effective electrochemical surface area by causing a large fraction of the ice to form in the gas diffusion layer rather than in the cathode catalyst layer. Preheating the feed gases, using the power generated to electrically heat the stack, and operating pressures have only small effect on the ability to self-start or the startup time. In subfreezing weather, the stack shut-down protocol should include flowing ambient air through the hot cathode passages to vaporize liquid water remaining in the cathode catalyst. Self-start is faster and more robust if the bipolar plates are made from metal rather than graphite.

  2. Composite solid polymer electrolyte membranes

    Energy Technology Data Exchange (ETDEWEB)

    Formato, Richard M. (Shrewsbury, MA); Kovar, Robert F. (Wrentham, MA); Osenar, Paul (Watertown, MA); Landrau, Nelson (Marlborough, MA); Rubin, Leslie S. (Newton, MA)

    2001-06-19

    The present invention relates to composite solid polymer electrolyte membranes (SPEMs) which include a porous polymer substrate interpenetrated with an ion-conducting material. SPEMs of the present invention are useful in electrochemical applications, including fuel cells and electrodialysis.

  3. Dynamic evaluation of low-temperature metal-supported solid oxide fuel cell oriented to auxiliary power units

    Science.gov (United States)

    Wang, Zhenwei; Berghaus, Jörg Oberste; Yick, Sing; Decès-Petit, Cyrille; Qu, Wei; Hui, Rob; Maric, Radenka; Ghosh, Dave

    A metal-supported solid oxide fuel cell (SOFC) composed of a Ni-Ce 0.8Sm 0.2O 2- δ (Ni-SDC) cermet anode and an SDC electrolyte was fabricated by suspension plasma spraying on a Hastelloy X substrate. The cathode, an Sm 0.5Sr 0.5CoO 3 (SSCo)-SDC composite, was screen-printed and fired in situ. The dynamic behaviour of the cell was measured while subjected to complete fuel shutoff and rapid start-up cycles, as typically encountered in auxiliary power units (APU) applications. A promising performance - with a maximum power density (MPD) of 0.176 W cm -2 at 600 °C - was achieved using humidified hydrogen as fuel and air as the oxidant. The cell also showed excellent resistance to oxidation at 600 °C during fuel shutoff, with only a slight drop in performance after reintroduction of the fuel. The Cr and Mn species in the Hastelloy X alloy appeared to be preferentially oxidized while the oxidation of nickel in the metallic substrate was temporarily alleviated. In rapid start-up cycles with a heating rate of 60 °C min -1, noticeable performance deterioration took place in the first two thermal cycles, and then continued at a much slower rate in subsequent cycles. A postmortem analysis of the cell suggested that the degradation was mainly due to the mismatch of the thermal expansion coefficient across the cathode/electrolyte interface.

  4. Improvement in High-voltage Performance of Lithium-ion Batteries Using Bismaleimide as an Electrolyte Additive

    International Nuclear Information System (INIS)

    Highlights: • Bismaleimide is found as an additive to enhance electrolyte performance. • Performance of LiCoO2/Li cells is improved while charging the cell up to 4.5 V. • The electrolyte stability is improved to be 5.0 V after the addition. • The surface film formation on cathode is crucial during first cycles. - Abstract: N,N′-4,4′-diphenylmethane-bismaleimide (BMI) is attempted to enhance the high-voltage performance for lithium-ion batteries. When 0.1% (m/v) BMI is added into the control electrolyte, the high-voltage cycling performance of LiCoO2/Li cells is improved evidently while charging the cell up to 4.5 V rather than the conventional 4.2 V. Analysis of scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) demonstrate that an interface film forms on the cathode surface from BMI in electrolyte. AC impedance spectra and charge/discharge test were tested after incubation of the charged cell at 60 °C. Linear sweep voltammetry (LSV) is used to test the electrochemical stability window of the electrolyte with BMI addition. The results demonstrate that the improvement of high-voltage performance is attributed to the surface film on cathode. In addition, the BMI addition does not cause damage in conventional performance with 4.2 V electrochemical window. The BMI-containing electrolyte provides high-voltage cycling performance with 4.5 V electrochemical window, making LiCoO2 battery a simple and promising system for applications with high energy density

  5. A pulsed cathodic arc spacecraft propulsion system

    Science.gov (United States)

    Neumann, P. R. C.; Bilek, M. M. M.; Tarrant, R. N.; McKenzie, D. R.

    2009-11-01

    We investigate the use of a centre-triggered cathodic arc as a spacecraft propulsion system that uses an inert solid as a source of plasma. The cathodic vacuum arc produces almost fully ionized plasma with a high exhaust velocity (>104 m s-1), giving a specific impulse competitive with other plasma or ion thrusters. A centre trigger design is employed that enables efficient use of cathode material and a high pulse-to-pulse repeatability. We compare three anode geometries, two pulse current profiles and two pulse durations for their effects on impulse generation, energy and cathode material usage efficiency. Impulse measurement is achieved through the use of a free-swinging pendulum target constructed from a polymer material. Measurements show that impulse is accurately controlled by varying cathode current. The cylindrical anode gave the highest energy efficiency. Cathode usage is optimized by choosing a sawtooth current profile. There is no requirement for an exhaust charge neutralization system.

  6. Electrolytes for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Vaughey, John; Jansen, Andrew N.; Dees, Dennis W.

    2014-08-05

    A family of electrolytes for use in a lithium ion battery. The genus of electrolytes includes ketone-based solvents, such as, 2,4-dimethyl-3-pentanone; 3,3-dimethyl 2-butanone(pinacolone) and 2-butanone. These solvents can be used in combination with non-Lewis Acid salts, such as Li.sub.2[B.sub.12F.sub.12] and LiBOB.

  7. High cation transport polymer electrolyte

    Science.gov (United States)

    Gerald, II, Rex E.; Rathke, Jerome W.; Klingler, Robert J.

    2007-06-05

    A solid state ion conducting electrolyte and a battery incorporating same. The electrolyte includes a polymer matrix with an alkali metal salt dissolved therein, the salt having an anion with a long or branched chain having not less than 5 carbon or silicon atoms therein. The polymer is preferably a polyether and the salt anion is preferably an alkyl or silyl moiety of from 5 to about 150 carbon/silicon atoms.

  8. Wetting phenomena in electrolyte solutions

    OpenAIRE

    Ibagon, Ingrid

    2014-01-01

    The present study analyzes wetting phenomena in electrolyte solutions. They are investigated by means of classical density functional theory. First, the wetting of a charged substrate by an electrolyte solution is studied with emphasis on the influence of the substrate charge density and of the ionic strength on the wetting transition temperature and on the order of the wetting transition. The corresponding models consist of solvent particles, anions, and cations. Two mean field approaches ar...

  9. An Aurivillius Oxide Based Cathode with Excellent CO2 Tolerance for Intermediate-Temperature Solid Oxide Fuel Cells.

    Science.gov (United States)

    Zhu, Yinlong; Zhou, Wei; Chen, Yubo; Shao, Zongping

    2016-07-25

    The Aurivillius oxide Bi2 Sr2 Nb2 MnO12-δ (BSNM) was used as a cobalt-free cathode for intermediate-temperature solid oxide fuel cells (IT-SOFCs). To the best of our knowledge, the BSNM oxide is the only alkaline-earth-containing cathode material with complete CO2 tolerance that has been reported thus far. BSNM not only shows favorable activity in the oxygen reduction reaction (ORR) at intermediate temperatures but also exhibits a low thermal expansion coefficient, excellent structural stability, and good chemical compatibility with the electrolyte. These features highlight the potential of the new BSNM material as a highly promising cathode material for IT-SOFCs.

  10. An Aurivillius Oxide Based Cathode with Excellent CO2 Tolerance for Intermediate-Temperature Solid Oxide Fuel Cells.

    Science.gov (United States)

    Zhu, Yinlong; Zhou, Wei; Chen, Yubo; Shao, Zongping

    2016-07-25

    The Aurivillius oxide Bi2 Sr2 Nb2 MnO12-δ (BSNM) was used as a cobalt-free cathode for intermediate-temperature solid oxide fuel cells (IT-SOFCs). To the best of our knowledge, the BSNM oxide is the only alkaline-earth-containing cathode material with complete CO2 tolerance that has been reported thus far. BSNM not only shows favorable activity in the oxygen reduction reaction (ORR) at intermediate temperatures but also exhibits a low thermal expansion coefficient, excellent structural stability, and good chemical compatibility with the electrolyte. These features highlight the potential of the new BSNM material as a highly promising cathode material for IT-SOFCs. PMID:27294808

  11. Wetting in electrolyte solutions.

    Science.gov (United States)

    Ibagon, Ingrid; Bier, Markus; Dietrich, S

    2013-06-01

    Wetting of a charged substrate by an electrolyte solution is investigated by means of classical density functional theory applied to a lattice model. Within the present model the pure, i.e., salt-free solvent, for which all interactions are of the nearest-neighbor type only, exhibits a second-order wetting transition for all strengths of the substrate-particle and the particle-particle interactions for which the wetting transition temperature is nonzero. The influences of the substrate charge density and of the ionic strength on the wetting transition temperature and on the order of the wetting transition are studied. If the substrate is neutral, the addition of salt to the solvent changes neither the order nor the transition temperature of the wetting transition of the system. If the surface charge is nonzero, upon adding salt this continuous wetting transition changes to first-order within the wide range of substrate surface charge densities and ionic strengths studied here. As the substrate surface charge density is increased, at fixed ionic strength, the wetting transition temperature decreases and the prewetting line associated with the first-order wetting transition becomes longer. This decrease of the wetting transition temperature upon increasing the surface charge density becomes more pronounced by decreasing the ionic strength. PMID:23758391

  12. Performance enhancement of thin-film ceramic electrolyte fuel cell using bi-layered yttrium-doped barium zirconate

    International Nuclear Information System (INIS)

    A thin-film yttrium-doped barium zirconate comprised of two distinct layers with different porosity was fabricated by pulsed laser deposition method for a low-temperature solid oxide fuel cell electrolyte to enhance electrode reactions and suppress electric short-circuit problem simultaneously. At 250 °C, the peak power density of bi-layer electrolyte fuel cell was ∼ 2 mW/cm2, which is ∼ 56% higher than that of single-layer electrolyte fuel cell due to significant reduction of cathodic activation loss. A set of materials characterizations revealed that the differences in compositions and micro-structures at the electrolytes accounts for the improved performance. - Highlights: • Bi-layer thin-film electrolyte was fabricated with pulsed laser deposition method. • Electrochemical performance was investigated at 250 °C. • The porous layer at the cathode surface improved oxygen reduction reaction. • Compositional and structural properties were examined with ex situ characterizations

  13. Nanotubes of rare earth cobalt oxides for cathodes of intermediate-temperature solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Sacanell, Joaquin [Departamento de Fisica, Centro Atomico Constituyentes, CNEA, Av. Gral. Paz 1499, 1650 San Martin, Buenos Aires (Argentina); CINSO (Centro de Investigaciones en Solidos), CITEFA-CONICET, J.B. de La Salle 4397, 1603 Villa Martelli, Buenos Aires (Argentina); Leyva, A. Gabriela [Departamento de Fisica, Centro Atomico Constituyentes, CNEA, Av. Gral. Paz 1499, 1650 San Martin, Buenos Aires (Argentina); Escuela de Ciencia y Tecnologia, UNSAM. Av. Gral. Paz 1499, 1650 San Martin, Buenos Aires (Argentina); Bellino, Martin G.; Lamas, Diego G. [CINSO (Centro de Investigaciones en Solidos), CITEFA-CONICET, J.B. de La Salle 4397, 1603 Villa Martelli, Buenos Aires (Argentina)

    2010-04-02

    In this work we studied the electrochemical properties of cathodes for intermediate-temperature solid oxide fuel cells (IT-SOFCs) prepared with nanotubes of La{sub 0.6}Sr{sub 0.4}CoO{sub 3} (LSCO). Their nanostructures consist of agglomerated nanoparticles in tubular structures of sub-micrometric diameter. The resulting cathodes are highly porous both at the micro- and the nanoscale. This fact increases significantly the access to active sites for the oxygen reduction. We investigated the influence of the diameter of the precursor nanotubes on the polarization resistance of the LSCO cathodes on CeO{sub 2}-10 mol.% Sm{sub 2}O{sub 3} (SDC) electrolytes under air atmosphere, evaluated in symmetrical [LSCO/SDC/LSCO] cells. Our results indicate an optimized performance when the diameter of precursor nanotubes is sufficiently small to become dense nanorods after cathode sintering. We present a phenomenological model that successfully explains the behavior observed and considers that a small starting diameter acts as a barrier that prevents grains growth. This is directly related with the lack of contact points between nanotubes in the precursor, which are the only path for the growth of ceramic grains. We also observed that a conventional sintering process (of 1 h at 1000 C with heating and cooling rates of 10 C min{sup -1}) has to be preferred against a fast firing one (1 or 2 min at 1100 C with heating and cooling rates of 100 C min{sup -1}) in order to reach a higher performance. However, a good adhesion of the cathode can be achieved with both methods. Our results suggest that oxygen vacancy diffusion is enhanced while decreasing LSCO particle size. This indicates that the high performance of our nanostructured cathodes is not only related with the increase of the number of active sites for oxygen reduction but also to the fact that the nanotubes are formed by nanoparticles. (author)

  14. Un nouveau concept de séparation actinides-lanthanides en milieu sel fondu : mise en oeuvre d'une cathode liquide à surface renouvelée

    OpenAIRE

    Huguet, Anne

    2009-01-01

    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 seems promising for a group actinides co-recycling. The aim of the study is to propose, define and initiate the development of an electrolytic pyroprocess dedicated to the quantitative and selective recovery...

  15. Nanoscale Surface Modification of Lithium-Rich Layered-Oxide Composite Cathodes for Suppressing Voltage Fade.

    Science.gov (United States)

    Zheng, Fenghua; Yang, Chenghao; Xiong, Xunhui; Xiong, Jiawen; Hu, Renzong; Chen, Yu; Liu, Meilin

    2015-10-26

    Lithium-rich layered oxides are promising cathode materials for lithium-ion batteries and exhibit a high reversible capacity exceeding 250 mAh g(-1) . However, voltage fade is the major problem that needs to be overcome before they can find practical applications. Here, Li1.2 Mn0.54 Ni0.13 Co0.13 O2 (LLMO) oxides are subjected to nanoscale LiFePO4 (LFP) surface modification. The resulting materials combine the advantages of both bulk doping and surface coating as the LLMO crystal structure is stabilized through cationic doping, and the LLMO cathode materials are protected from corrosion induced by organic electrolytes. An LLMO cathode modified with 5 wt % LFP (LLMO-LFP5) demonstrated suppressed voltage fade and a discharge capacity of 282.8 mAh g(-1) at 0.1 C with a capacity retention of 98.1 % after 120 cycles. Moreover, the nanoscale LFP layers incorporated into the LLMO surfaces can effectively maintain the lithium-ion and charge transport channels, and the LLMO-LFP5 cathode demonstrated an excellent rate capacity.

  16. Nanoscale Surface Modification of Lithium-Rich Layered-Oxide Composite Cathodes for Suppressing Voltage Fade.

    Science.gov (United States)

    Zheng, Fenghua; Yang, Chenghao; Xiong, Xunhui; Xiong, Jiawen; Hu, Renzong; Chen, Yu; Liu, Meilin

    2015-10-26

    Lithium-rich layered oxides are promising cathode materials for lithium-ion batteries and exhibit a high reversible capacity exceeding 250 mAh g(-1) . However, voltage fade is the major problem that needs to be overcome before they can find practical applications. Here, Li1.2 Mn0.54 Ni0.13 Co0.13 O2 (LLMO) oxides are subjected to nanoscale LiFePO4 (LFP) surface modification. The resulting materials combine the advantages of both bulk doping and surface coating as the LLMO crystal structure is stabilized through cationic doping, and the LLMO cathode materials are protected from corrosion induced by organic electrolytes. An LLMO cathode modified with 5 wt % LFP (LLMO-LFP5) demonstrated suppressed voltage fade and a discharge capacity of 282.8 mAh g(-1) at 0.1 C with a capacity retention of 98.1 % after 120 cycles. Moreover, the nanoscale LFP layers incorporated into the LLMO surfaces can effectively maintain the lithium-ion and charge transport channels, and the LLMO-LFP5 cathode demonstrated an excellent rate capacity. PMID:26335589

  17. Bilirubin oxidase based enzymatic air-breathing cathode: Operation under pristine and contaminated conditions.

    Science.gov (United States)

    Santoro, Carlo; Babanova, Sofia; Erable, Benjamin; Schuler, Andrew; Atanassov, Plamen

    2016-04-01

    The performance of bilirubin oxidase (BOx) based air breathing cathode was constantly monitored over 45 days. The effect of electrolyte composition on the cathode oxygen reduction reaction (ORR) output was investigated. Particularly, deactivation of the electrocatalytic activity of the enzyme in phosphate buffer saline (PBS) solution and in activated sludge (AS) was evaluated. The greatest drop in current density was observed during the first 3 days of constant operation with a decrease of ~60 μA cm(-2) day(-1). The rate of decrease slowed to ~10 μA cm(-2) day(-1) (day 3 to 9) and then to ~1.5 μA cm(-2)day(-1) thereafter (day 9 to 45). Despite the constant decrease in output, the BOx cathode generated residual current after 45 days operations with an open circuit potential (OCP) of 475 mV vs. Ag/AgCl. Enzyme deactivation was also studied in AS to simulate an environment close to the real waste operation with pollutants, solid particles and bacteria. The presence of low-molecular weight soluble contaminants was identified as the main reason for an immediate enzymatic deactivation within few hours of cathode operation. The presence of solid particles and bacteria does not affect the natural degradation of the enzyme.

  18. Asymmetric battery having a semi-solid cathode and high energy density anode

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Taison; Chiang, Yet-Ming; Ota, Naoki; Wilder, Throop; Duduta, Mihai

    2016-09-06

    Embodiments described herein relate generally to devices, systems and methods of producing high energy density batteries having a semi-solid cathode that is thicker than the anode. An electrochemical cell can include a positive electrode current collector, a negative electrode current collector and an ion-permeable membrane disposed between the positive electrode current collector and the negative electrode current collector. The ion-permeable membrane is spaced a first distance from the positive electrode current collector and at least partially defines a positive electroactive zone. The ion-permeable membrane is spaced a second distance from the negative electrode current collector and at least partially defines a negative electroactive zone. The second distance is less than the first distance. A semi-solid cathode that includes a suspension of an active material and a conductive material in a non-aqueous liquid electrolyte is disposed in the positive electroactive zone, and an anode is disposed in the negative electroactive zone.

  19. Study and characterization of positive electrolytes for application in the aqueous all-copper redox flow battery

    Science.gov (United States)

    Sanz, Laura; Lloyd, David; Magdalena, Eva; Palma, Jesús; Anderson, Marc; Kontturi, Kyösti

    2015-03-01

    In recent studies, the employment of the aqueous solution system comprised of Cu(II)-Cu(I)-Cl system was addressed for massive energy storage in Redox Flow Batteries (RFBs) [5,6], providing important practical advantages compared to the widespread all-vanadium or Zn/Br systems [5]. The substitution of vanadium electrolytes by copper-chloride electrolytes allows the simplification of the process and notably reduces the cost, allowing for a better commercialization of RFBs. Here, a complete physico-chemical characterization of positive copper electrolytes and their electrochemical performance using different supporting electrolytes, HCl and CaCl2, is presented. Once the physical properties and the electrochemical performance of each one of the supporting electrolytes were determined, the final composition of supporting electrolyte for this Cu(II)/Cu(I) redox couple could be optimized by mixing different sources of chloride, regarding its practical application in the all-copper RFB.

  20. Thermal Synergy Effect between LiNi0.5Co0.2Mn0.3O2 and LiMn2O4 Enhances the Safety of Blended Cathode for Lithium Ion Batteries.

    Science.gov (United States)

    Wang, Jing; Yu, Yangyang; Li, Bing; Zhang, Peng; Huang, Jianxin; Wang, Feng; Zhao, Shiyong; Gan, Chaolun; Zhao, Jinbao

    2016-08-10

    The layer-structured LiNi0.5Co0.2Mn0.3O2 (L523) with high specific capacity and the spinel LiMn2O4 (LMO) with excellent thermostability complement each other in a blended cathode for better heat stability and electrochemical performance. The delithiated LMO starts to react with electrolyte at 160-200 °C to cause structural instability, and the delithiated L523 generates massive heat when its temperature is raised above 275 °C with the electrolyte present, but we found that the blended cathode shows a remarkable improvement in thermal stability since the reaction at 160-200 °C between LMO and the electrolyte disappears, and the total heat generated from the reaction between L523 and the electrolyte is drastically reduced. The reaction between LMO and the electrolyte at 160-200 °C causes structural instability of LMO as a self-accelerating attack from HF. With L523 present, this reaction is eliminated because the H(+) from HF and Li(+) in L523 undergo exchange reaction to prevent further generation of HF. The presence of LMO, however, reduces the total heat generated by L523 reacting with the electrolyte at high temperature. This thermal synergy between LMO and L523 not only improves the thermal safety of the blended cathode but also preserves their structures for better electrochemical performance. PMID:27448087

  1. Use of Both Anode and Cathode Reactions in Wastewater Treatment

    Science.gov (United States)

    Brillas, Enric; Sirés, Ignasi; Cabot, Pere LluíS.

    Here, we describe the fundamentals, laboratory experiments, and environmental applications of indirect electrooxidation methods based on H2O2 electrogeneration such as electro-Fenton, photoelectro-Fenton and peroxicoagulation for the treatment of acidic wastewaters containing toxic and recalcitrant organics. These methods are electrochemical advanced oxidation processes that can be used in divided and undivided electrolytic cells in which pollutants are oxidized by hydroxyl radical (•OH) produced from anode and/or cathode reactions. H2O2 is generated from the two-electron reduction of O2 at reticulated vitreous carbon, graphite, carbon-felt, and O2-diffusion cathodes. The most usual method is electro-Fenton where Fe2 + added to the wastewater reacts with electrogenerated H2O2 to yield •OH and Fe3 + from Fenton's reaction. An advantage of this technique is that Fe2 + is continuously regenerated from cathodic reduction of Fe3 +. The characteristics of different electro-Fenton systems where pollutants are simultaneously destroyed by •OH formed in the medium from Fenton's reaction and at the anode surface from water oxidation are explained. The effect of the anode [Pt or boron-doped diamond (BDD)] and cathode (carbon-felt or O2-diffusion) on the degradation rate of persistent industrial by-products, herbicides, pharmaceuticals, dyes, etc. is examined. Initial pollutants react much more rapidly with •OH formed in the medium and their degradation sequences are discussed from aromatic intermediates and finally short aliphatic acids are detected. The synergetic positive catalytic effect of Cu2 + on the electro-Fenton process is evidenced. The photoelectro-Fenton method involves the irradiation of the wastewater with UVA light that rapidly photodecomposes complexes of Fe3 + with final carboxylic acids enhancing total decontamination. The peroxicoagulation method uses a sacrificial Fe anode that is continuously oxidized to Fe2 + and organics are either mineralized

  2. Solid polymer electrolyte fuel cells

    International Nuclear Information System (INIS)

    The report summarizes the state of art of systems for energy production in electrical vehicles, looking into the general characteristics of electrodes and membranes. The water and thermal balance of the cell in relation to operative conditions, the pressure and temperature influence on the performance are examined. Special emphasis is given to the electrode characteristics-fabrication techniques and assembly of membrane electrodes. The problems related to the oxygen reduction kinetics at the cathode are examined, in relation to the fabrication techniques and to operative conditions of the cells. Finally, the possible alternative catalyzers for anode and cathode are reviewed

  3. Performance and Electrochemical Characterisation of Thin Electrolyte SOFCs

    DEFF Research Database (Denmark)

    Ramos, Tania; Hjelm, Johan; Wandel, Marie Emilie;

    2008-01-01

    The performance and electrochemical behavior of two anode-supported thin electrolyte cells, with different manufacturing parameters, is determined by polarization measurements and electrochemical impedance spectroscopy (EIS). In addition to characterization, a previously suggested equivalent......-depth electrochemical characterization can provide valuable guidelines for production/performance optimization. © 2008 ECS - The Electrochemical Society...

  4. Square wave cathodic stripping voltammetric technique for determination of Aflatoxin B1 in ground nut sample

    International Nuclear Information System (INIS)

    An electro analytical method has been developed for the detection and determination of 2,3,6a,9a-tetrahydro-4-methoxy cyclo penta[c] furo[3, 2:4,5] furo [2,3-h][l] benzopyrane-1,11-dione (aflatoxin B1, AFB1) by a square wave cathodic stripping voltammetric (SWSV) technique on a hanging mercury drop electrode (HMDE) in aqueous solution with Britton-Robinson Buffer (BRB) at pH 9.0 as the supporting electrolyte. Effect of instrumental parameters such as accumulation potential (Eacc), accumulation time (tacc), scan rate (v), square wave frequency, step potential and pulse amplitude were examined. The best condition were found to be Eacc of -0.8 V, tacc of 100 s, v of 3750 mVs-1, frequency of 125 Hz, voltage step of 30 mV and pulse amplitude of 50 mV. Calibration curve was linear in the range of 0.01 to 0.15 μM with a detection limit of 0.125 x 10-8 M. Relative standard deviation for a replicate measurement of AFB1 (n = 5) with a concentration of 0.01 μM was 0.83 % with a peak potential of -1.30 V (against Ag/ AgCl). The recovery values obtained in spiked ground nut elute sample were 94.00 ± 0.67 % for 3.0 ppb, 91.22 ± 1.56 % for 9 ppb and 92.56 ± 2.00 % for 15.0 ppb of AFB1. The method was applied for the determination of the AFB1 in ground nut samples after extraction and clean-up steps. The results were compared with that obtained by high performance liquid chromatography (HPLC) technique. (author)

  5. Neutral electrolyte aluminum air battery with open configuration

    Institute of Scientific and Technical Information of China (English)

    HAN Bin; LIANG Guangchuan

    2006-01-01

    A kind of new long life aluminum air batteries with open configuration was developed, using aluminum alloy doped with Ga, In, Sn, Bi, Pb and Mn as anode, NaCl solution as electrolyte and air electrode as cathode. The polarization curves of aluminum electrode and air electrode were tested. And the cell's performance was tested to calculate the utilization of aluminum electrode and the energy density. It is shown that, in the 3.5% NaCl solution, the cell can discharge at 0.29 A for 140 h with the working voltage keeping over 1.1 V. The utilization ratio of aluminum anode is over 44%, and the life of battery is longer than 2400 h.

  6. Hydroxyl radical production in plasma electrolysis with KOH electrolyte solution

    Energy Technology Data Exchange (ETDEWEB)

    Saksono, Nelson; Febiyanti, Irine Ayu, E-mail: irine.ayu41@ui.ac.id; Utami, Nissa; Ibrahim [Department of Chemical Engineering, Universitas Indonesia, Depok 16424, Indonesia Phone: +62217863516, Fax: +62217863515 (Indonesia)

    2015-12-29

    Plasma electrolysis is an effective technology for producing hydroxyl radical (•OH). This method can be used for waste degradation process. This study was conducted to obtain the influence of applied voltage, electrolyte concentration, and anode depth in the plasma electrolysis system for producing hydroxyl radical. The materials of anode and cathode, respectively, were made from tungsten and stainless steel. KOH solution was used as the solution. Determination of hydroxyl radical production was done by measuring H{sub 2}O{sub 2} amount formed in plasma system using an iodometric titration method, while the electrical energy consumed was obtained by measuring the electrical current throughout the process. The highest hydroxyl radical production was 3.51 mmol reached with 237 kJ energy consumption in the power supply voltage 600 V, 0.02 M KOH, and 0.5 cm depth of anode.

  7. Isotope effects in electrolytic formation of lithium amalgam

    International Nuclear Information System (INIS)

    Isotope effects in the lithium amalgam formation were studied by using the mercury cathode and LiOH solutions. The electrolyses were carried out at different conditions of both applied voltages 4 ∼ 10 V, and the concentrations of initially charged LiOH, 0.5 ∼ 5 mol/dm3. Higher efficiency of electrolytic amalgam formation was observed at higher LiOH concentrations and higher applied voltages. At these conditions, however, significant amount of solid amalgam was produced in the mercury phase. From the isotopic analyses on the samples taken during the electrolyses, it was found that the isotopic equilibrium was attained between the aqueous and the liquid amalgam phases. The isotopic equilibrium constant (isotope separation factor) was determined as 1.056 (average value for all the experiments) at 20 deg C. (author)

  8. The Stirred Tank Reactor Polymer Electrolyte Membrane Fuel Cell

    CERN Document Server

    Benziger, J; Karnas, E; Moxley, J; Teuscher, C; Kevrekidis, Yu G; Benziger, Jay

    2003-01-01

    The design and operation of a differential Polymer Electrolyte Membrane (PEM) fuel cell is described. The fuel cell design is based on coupled Stirred Tank Reactors (STR); the gas phase in each reactor compartment was well mixed. The characteristic times for reactant flow, gas phase diffusion and reaction were chosen so that the gas compositions at both the anode and cathode are uniform. The STR PEM fuel cell is one-dimensional; the only spatial gradients are transverse to the membrane. The STR PEM fuel cell was employed to examine fuel cell start- up, and its dynamic responses to changes in load, temperature and reactant flow rates. Multiple time scales in systems response are found to correspond to water absorption by the membrane, water transport through the membrane and stress-related mechanical changes of the membrane.

  9. Hydroxyl radical production in plasma electrolysis with KOH electrolyte solution

    Science.gov (United States)

    Saksono, Nelson; Febiyanti, Irine Ayu; Utami, Nissa; Ibrahim

    2015-12-01

    Plasma electrolysis is an effective technology for producing hydroxyl radical (•OH). This method can be used for waste degradation process. This study was conducted to obtain the influence of applied voltage, electrolyte concentration, and anode depth in the plasma electrolysis system for producing hydroxyl radical. The materials of anode and cathode, respectively, were made from tungsten and stainless steel. KOH solution was used as the solution. Determination of hydroxyl radical production was done by measuring H2O2 amount formed in plasma system using an iodometric titration method, while the electrical energy consumed was obtained by measuring the electrical current throughout the process. The highest hydroxyl radical production was 3.51 mmol reached with 237 kJ energy consumption in the power supply voltage 600 V, 0.02 M KOH, and 0.5 cm depth of anode.

  10. Hydroxyl radical production in plasma electrolysis with KOH electrolyte solution

    International Nuclear Information System (INIS)

    Plasma electrolysis is an effective technology for producing hydroxyl radical (•OH). This method can be used for waste degradation process. This study was conducted to obtain the influence of applied voltage, electrolyte concentration, and anode depth in the plasma electrolysis system for producing hydroxyl radical. The materials of anode and cathode, respectively, were made from tungsten and stainless steel. KOH solution was used as the solution. Determination of hydroxyl radical production was done by measuring H2O2 amount formed in plasma system using an iodometric titration method, while the electrical energy consumed was obtained by measuring the electrical current throughout the process. The highest hydroxyl radical production was 3.51 mmol reached with 237 kJ energy consumption in the power supply voltage 600 V, 0.02 M KOH, and 0.5 cm depth of anode

  11. Cathode-follower power amplifier

    International Nuclear Information System (INIS)

    In circular accelerators and particularly in storage rings it is essential that the total impedance, as seen by the beam, be kept below some critical value. A model of the accelerating system was built using a single-ended cathode-follower amplifier driving a ferrite-loaded cavity. The system operated at 234.5 kHz with a peak output voltage of +-10 kV on the gap. The dynamic output impedance, as measured on the gap, was < 15 ohms

  12. Scalable plasticized polymer electrolytes reinforced with surface-modified sepiolite fillers - A feasibility study in lithium metal polymer batteries

    Science.gov (United States)

    Mejía, Alberto; Devaraj, Shanmukaraj; Guzmán, Julio; Lopez del Amo, Juan Miguel; García, Nuria; Rojo, Teófilo; Armand, Michel; Tiemblo, Pilar

    2016-02-01

    Electrochemical properties of (polyethylene oxide) (PEO)/lithium trifluoromethanesulfonate (LiTf)/ethylene carbonate (EC)/sepiolite extruded composite electrolytes were studied. Appreciable electrochemical stability of 4.5 V at 70 °C was observed for polymer composite membranes with D-α-tocopherol-polyethylene glycol 1000 succinate-coated sepiolite fillers. Lithium plating/stripping analysis indicated no evidence of dendrite formation with good interfacial properties which were further confirmed by postmortem analysis of the cells. Solid state NMR studies show the presence of two Li+ population in the membranes. The feasibility of these electrolytes has been shown with LiFePO4 cathode materials. Initial discharge capacity of 142 mAh/g was observed remaining at 110 mAh/g after 25 cycles with a coulombic efficiency of 96%. The upscaling of these polymers can be easily achieved by extrusion technique and the capacity can be improved by varying the cathode architecture.

  13. 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

    2016-01-01

    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. PMID:27553901

  14. A high performance hybrid battery based on aluminum anode and LiFePO4 cathode.

    Science.gov (United States)

    Sun, Xiao-Guang; Bi, Zhonghe; Liu, Hansan; Fang, Youxing; Bridges, Craig A; Paranthaman, M Parans; Dai, Sheng; Brown, Gilbert M

    2016-01-28

    A novel hybrid battery utilizing an aluminum anode, a LiFePO4 cathode and an acidic ionic liquid electrolyte based on 1-ethyl-3-methylimidazolium chloride (EMImCl) and aluminum trichloride (AlCl3) (EMImCl-AlCl3, 1-1.1 in molar ratio) with or without LiAlCl4 is proposed. The hybrid ion battery delivers an initial high capacity of 160 mA h g(-1) at a current rate of C/5. It also shows good rate capability and cycling performance. PMID:26666453

  15. Electrochemical behavior of LiFePO4 cathode materials in the presence of anion adsorbents

    International Nuclear Information System (INIS)

    The poor rate capability is a major problem of olivine-structured lithium iron phosphate (LFP) cathode material in lithium-ion batteries due to its low electric conductivity and sluggish lithium diffusion. Other than the custom strategies to solve this problem like carbon coating and nano-size treatment, we simply mixed LFP with some anion adsorbents, which can store anions from the electrolytes swiftly. The effect of anion adsorbents on the performance of LFP composite electrode has been investigated by cyclic voltammetric tests and the corresponding apparent lithium diffusion coefficients have been measured

  16. Studies on Spinel LiMn2O4 Cathode Material Synthesized from Different Mn Sources

    Institute of Scientific and Technical Information of China (English)

    唐致远; 冯季军; 彭亚宁

    2004-01-01

    The spinel LiMn2O4 cathode material was synthesized with the solid-state reaction method. Four manganese compounds including electrolytic manganese dioxide (EMD), MnCO3, Mn3O4 and nano-EMD were used as Mn sources while LiOH·H2O was used as the uniform Li source. The crystal structure characteristics of these samples produced were investigated by means of XRD, SEM, particle size distribution analysis and specific surface area testing. Their electrochemical properties were also studied by comparing their specific capacity, charge and discharge efficiency and cycle performance.

  17. Properties of sodium-based ionic liquid electrolytes for sodium secondary battery applications

    International Nuclear Information System (INIS)

    The enormous demands on available global lithium resources have raised concerns about the sustainability of the supply of lithium. Sodium secondary batteries have emerged as promising alternatives to lithium batteries. We describe here sodium bis(trifluoromethylsulfonyl) amide (NaNTf2) electrolyte systems based on 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl) amide (C4mpyrNTf2) ionic liquids. The electrochemical stability of the system was examined; a pair of facile cathodic and anodic processes around 0 V vs. Na/Na+ were observed in cyclic voltammetry measurements and interpreted as deposition and dissolution of sodium metal. Density, viscosity and conductivity of the electrolytes were studied. It was found that the ionic conductivity of electrolytes reached as high as 8 mS/cm, decreasing slowly as the salt content increased due to increasing of viscosity and density of the electrolyte. Therefore, sodium electrolytes based on C4mpyrNTf2 appear to be promising for secondary sodium battery applications

  18. Electron transfer processes occurring on platinum neural stimulating electrodes: pulsing experiments for cathodic-first/charge-balanced/biphasic pulses for 0.566 ≤ k ≥ 2.3 in oxygenated and deoxygenated sulfuric acid

    Science.gov (United States)

    Kumsa, Doe W.; Montague, Fred W.; Hudak, Eric M.; Mortimer, J. Thomas

    2016-10-01

    The application of a train of cathodic-first/charge-balanced/biphasic pulses applied to a platinum electrode resulted in a positive creep of the anodic phase potential that increases with increasing charge injection but reaches a steady-state value before 1000 pulses have been delivered. The increase follows from the fact that charge going into irreversible reactions occurring during the anodic phase must equal the charge going into irreversible reactions during the cathodic phase for charge-balanced pulses. In an oxygenated electrolyte the drift of the measured positive potential moved into the platinum oxidation region of the i(V e) profile when the charge injection level exceeds k = 1.75. Platinum dissolution may occur in this region and k = 1.75 defines a boundary between damaging and non-damaging levels on the Shannon Plot. In a very low oxygen environment, the positive potential remained below the platinum oxidation region for the highest charge injection values studied, k = 2.3. The results support the hypothesis that platinum dissolution is the defining factor for the Shannon limit, k = 1.75. Numerous instrumentation issues were encountered in the course of making measurements. The solutions to these issues are provided.

  19. Poly(2,5-dimercapto-1,3,4-thiadiazole) as a Cathode for Rechargeable Lithium Batteries with Dramatically Improved Performance

    KAUST Repository

    Gao, Jie

    2012-05-29

    Organosulfur compounds with multiple thiol groups are promising for high gravimetric energy density electrochemical energy storage. We have synthesized a poly(2,5-dimercapto-1,3,4-thiadiazole) (PDMcT)/poly(3,4-ethylenedioxythiophene) (PEDOT) composite cathode for lithium-ion batteries with a new method and investigated its electrochemical behavior by charge/discharge cycles and cyclic voltammetry (CV) in an ether-based electrolyte. Based on a comparison of the electrochemical performance with a carbonate-based electrolyte, we found a much higher discharge capacity, but also a very attractive cycling performance of PDMcT by using a tetra(ethylene glycol) dimethyl ether (TEGDME)-based electrolyte. The first discharge capacity of the as-synthesized PDMcT/PEDOT composite approached 210 mAh g -1 in the TEGDME-based electrolyte. CV results clearly show that the redox reactions of PDMcT are highly reversible in this TEGDME-based electrolyte. The reversible capacity remained around 120 mAh g -1 after 20 charge/discharge cycles. With improved cycling performance and very low cost, PDMcT could become a very promising cathode material when combined with a TEGDME-based electrolyte. The poor capacity in the carbonate-based electrolyte is a consequence of the irreversible reaction of the DMcT monomer and dimer with the solvent, emphasizing the importance of electrolyte chemistry when studying molecular-based battery materials. The nature of the electrolyte has a dramatic effect on the performance of poly(2,5-dimercapto-1,3,4-thiadiazole) (PDMcT) as a cathode material in lithium-ion batteries. Whereas the use of an ethylene/diethyl carbonate (EC/DEC)-based electrolyte resulted in very poor performance, the use of a tetra(ethylene glycol) dimethyl ether (TEGDME)-based electrolyte dramatically improved the performance in terms of both the discharge capacity and capacity retention (see scheme). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Mechanistic Insight in the Function of Phosphite Additives for Protection of LiNi 0.5 Co 0.2 Mn 0.3 O 2 Cathode in High Voltage Li-Ion Cells

    Energy Technology Data Exchange (ETDEWEB)

    He, Meinan; Su, Chi-Cheung; Peebles, Cameron; Feng, Zhenxing; Connell, Justin G.; Liao, Chen; Wang, Yan; Shkrob, Ilya A.; Zhang, Zhengcheng

    2016-05-11

    Triethlylphosphite (TEP) and tris(2,2,2-trifluoroethyl) phosphite (TTFP) have been evaluated as electrolyte additives for high-voltage Li-ion battery cells using a Ni-rich layered cathode material LiNi0.5Co0.2Mn0.3O2 (NCM523) and the conventional carbonate electrolyte. The repeated charge/discharge cycling for cells containing 1 wt% of these additives was performed using an NCM523/graphite full cell operated at the voltage window from 3.0 to 4.6 V. During the initial charge process, these additives decompose on the cathode surface at a lower oxidation potential than the baseline electrolyte. Impedance spectroscopy and post-test analyses indicate the formation of protective coatings by both additives on the cathode surface that prevent oxidative breakdown of the electrolyte. However, only TTFP containing cells demonstrate the improved capacity retention and Coulombic efficiency. For TEP, the protective coating is also formed, but low Li+ ion mobility through the interphase layer results in inferior performance. These observations are rationalized through the inhibition of electrocatalytic centers present on the cathode surface and the formation of organophosphate deposits isolating the cathode surface from the electrolyte. The difference between the two phosphites clearly originates in the different properties of the resulting phosphate coatings, which may be in Li+ ion conductivity through such materials.