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Sample records for assisted electrolyte cell

  1. 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.

  2. Performance evaluation of solid oxide fuel cells with thin film electrolyte fabricated by binder-assisted slurry casting

    Energy Technology Data Exchange (ETDEWEB)

    Guo, W.M.; Liu, X.M.; Li, L.J. [Department of Biological and Chemical Engineering, Guangxi University of Technology, Liuzhou 545006 (China); Xiao, Y.F. [Department of Stomatology, Liuzhou Maternity and Child Health Hospital, Liuzhou 545001 (China); Chen, Y. [School of Yingdong Life Science, Shaoguan University, Shaoguan 512005 (China)

    2011-10-15

    A gas-tight yttria-stabilized zirconia (YSZ) electrolyte film was fabricated on porous NiO-YSZ anode substrates by a binder-assisted slurry casting technique. The scanning electron microscope (SEM) results showed that the YSZ film was relatively dense with a thickness of 10 {mu}m. La{sub 0.8}Sr{sub 0.2}MnO{sub 3} (LSM)-YSZ was applied to cathode using a screen-print technique and the single fuel cells were tested in a temperature range from 600 to 800 C. An open circuit voltage (OCV) of over 1.0 V was observed. The maximum power densities at 600, 700, and 800 C were 0.13, 0.44, and 1.1 W cm{sup -2}, respectively. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. 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.

  4. POLYMER ELECTROLYTE MEMBRANE FUEL CELLS

    DEFF Research Database (Denmark)

    2001-01-01

    A method for preparing polybenzimidazole or polybenzimidazole blend membranes and fabricating gas diffusion electrodes and membrane-electrode assemblies is provided for a high temperature polymer electrolyte membrane fuel cell. Blend polymer electrolyte membranes based on PBI and various...... thermoplastic polymers for high temperature polymer electrolyte fuel cells have also been developed. Miscible blends are used for solution casting of polymer membranes (solid electrolytes). High conductivity and enhanced mechanical strength were obtained for the blend polymer solid electrolytes. 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. 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.

  6. Electrolyte Additives for Phosphoric Acid Fuel Cells

    DEFF Research Database (Denmark)

    Gang, Xiao; Hjuler, H.A.; Olsen, C.A.;

    1993-01-01

    Electrochemical characteristics of a series of modified phosphoric acid electrolytes containing fluorinated car on compounds and silicone fluids as additives are presented. When used in phosphoric acid fuel cells, the modified electrolytes improve the performance due to the enhanced oxygen......, as a fuel-cell performance with the modified electrolytes. Specific conductivity measurements of some of the modified phosphoric acid electrolytes are reported. At a given temperature, the conductivity of the C4F9SO3K-modified electrolyte decreases with an increasing amount of the additive; the conductivity...... of the remains at the same value as the conductivity of the pure phosphoric acid. At a given composition, the conductivity of any modified electrolyte increases with temperature. We conclude that the improved cell performance for modified electrolytes is not due to any increase in conductivity....

  7. Electrolytic cell. [For separating anolyte and catholyte

    Science.gov (United States)

    Bullock, J.S.; Hale, B.D.

    1984-09-14

    An apparatus is described for the separation of the anolyte and the catholyte during electrolysis. The electrolyte flows through an electrolytic cell between the oppositely charged electrodes. The cell is equipped with a wedge-shaped device, the tapered end being located between the electrodes on the effluent side of the cell. The wedge diverts the flow of the electrolyte to either side of the wedge, substantially separating the anolyte and the catholyte.

  8. Organic electrolyte for nonaqueous cells

    Energy Technology Data Exchange (ETDEWEB)

    Blomgren, G.E.; Leger, V.Z.

    1989-02-28

    A nonaqueous electrolyte solution, for nonaqueous cells is described comprising a solute dissolved in a solvent, the solvent comprising at least one diether in which two oxygen atoms are separated by two carbon atoms in the sequence O/sub 1/C/sub 1/C/sub 2/O/sub 2/ and in which two or three contiguous atoms of the sequence are contained in a ring system of five, six or seven members in which the remaining ring atoms are carbon, or carbon and hetero atoms. When the oxygen atom O/sub 1/ or O/sub 2/, or oxygen atoms O/sub 1/ and O/sub 2/, are not included in the ring structure, a methyl group is bonded to the oxygen atom or atoms. The electrolyte solution contains at least one cosolvent selected from the group consisting of sulfolane, 3-methyl sulfolane; tetrahydrofuran; 2-methyltetrahydrofuran; 1,3-dioxolane; 3-methyl-oxazolidone; propylene carbonate; ..gamma.. (gamma)-butyrolactone; ..gamma.. (gamma)-valerolactone; ethylene glycol dimethylsulfite; dimethyl sulfoxide; and 1,1- and 1.2-dimethoxyethane.

  9. Effect of microstructure of TiN film on properties as bipolar plate coatings in polymer electrolyte membrane fuel cell prepared by inductively coupled plasma assisted magnetron sputtering

    International Nuclear Information System (INIS)

    As potential application in bipolar plate of polymer electrolyte membrane fuel cell, the microstructure, corrosion resistance and the electrical conductivity of titanium nitride (TiN) and Si doped titanium nitride (Ti0.9Si0.1N) films deposited by magnetron sputtering with different bias voltages are investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscope (AFM), electrochemical test and four-point probe method, respectively. XRD, SEM and AFM results reveal that the texture and topography of TiN film depend on the bias voltage and incorporation of Si. When the bias voltage is − 20 V and − 30 V, the TiN and Ti0.9Si0.1N films exhibit a dense (111) plane preferred growth, denser structure and smoother surface topography. The potentiodynamic test results indicate that the TiN and Ti0.9Si0.1N films have higher chemical inertness and better corrosion resistance. The films can satisfy the requirement of current density for bipolar plate materials. Incorporation of Si element into TiN film makes the passive current density more stable. Four-point probe measurement results show that the resistivity of both TiN and Ti0.9Si0.1N films reaches minimum when the deposition bias voltage is − 20 V. - Highlights: • Dense TiN and Ti0.9Si0.1N films are deposited by magnetron sputtering. • Preferred growth orientation of TiN depends on the bias voltage and Si doping. • TiN and Ti0.9Si0.1N films have excellent corrosion resistance. • Surface conductivity of TiN and Ti0.9Si0.1N films evolves with bias voltage

  10. Electrolytes for Wide Operating Temperature Lithium-Ion Cells

    Science.gov (United States)

    Smart, Marshall C. (Inventor); Bugga, Ratnakumar V. (Inventor)

    2016-01-01

    Provided herein are electrolytes for lithium-ion electrochemical cells, electrochemical cells employing the electrolytes, methods of making the electrochemical cells and methods of using the electrochemical cells over a wide temperature range. Included are electrolyte compositions comprising a lithium salt, a cyclic carbonate, a non-cyclic carbonate, and a linear ester and optionally comprising one or more additives.

  11. Recent results on aqueous electrolyte cells

    KAUST Repository

    Wessells, Colin

    2011-03-01

    The improved safety of aqueous electrolytes makes aqueous lithium-ion batteries an attractive alternative to commercial cells utilizing flammable and expensive organic electrolytes. Two important issues relating to their use have been addressed in this work. One is the extension of the usable voltage range by the incorporation of lithium salts, and the other is the investigation of a useful negative electrode reactant, LiTi 2(PO 4) 3. The electrochemical stability of aqueous lithium salt solutions containing two lithium salts, LiNO 3 and Li 2SO 4, has been characterized using a constant current technique. In both cases, concentrated solutions had effective electrolyte stability windows substantially greater than that of pure water under standard conditions. At an electrolyte leakage current of 10 μA cm -2 between two platinum electrodes in 5 M LiNO 3 the cell voltage can reach 2.0 V, whereas with a leakage current of 50 μA cm -2 it can reach 2.3 V. LiTi 2(PO 4) 3 was synthesized using a Pechini method and cycled in pH-neutral Li 2SO 4. At a reaction potential near the lower limit of electrolyte stability, an initial discharge capacity of 118 mAh g -1 was measured at a C/5 rate, while about 90% of this discharge capacity was retained after 100 cycles. This work demonstrates that it is possible to have useful aqueous electrolyte lithium-ion batteries using the LiTi 2(PO 4) 3 anode with cell voltages of 2 V and above. © 2010 Elsevier B.V. All rights reserved.

  12. Chelating agent assisted heat treatment of carbon supported cobalt oxide nanoparticle for use as cathode catalyst of polymer electrolyte membrane fuel cell (PEMFC)

    International Nuclear Information System (INIS)

    Cobalt-based catalysts for the oxygen reduction reaction (ORR) in polymer electrolyte membrane fuel cell (PEMFC) have been successfully incorporated cobalt oxide (Co3O4) onto Vulcan XC-72 carbon powder by thermal decomposition of Co-ethylenediamine complex (ethylenediamine, NH2CH2CH2NH2, denoted en) at 850 oC. The catalysts were prepared by adsorbing the cobalt complexes [Co(en)(H2O)4]3+, [Co(en)2(H2O)2]3+ and [Co(en)3]3+ on commercial XC-72 carbon black supports, loading amount of Co with respect to carbon black was about 2%, the resulting materials have been pyrolyzed under nitrogen atmosphere to create CoOx/C catalysts, donated as E1, E2, and E3, respectively. The composite materials were characterized using X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS). Chemical compositions of prepared catalysts were determined using inductively-coupled plasma-atomic emission spectroscopy (ICP-AES). The catalytic activities for ORR have been analyzed by cyclic voltammetry (CV) and linear sweep voltammetry (LSV). The electrocatalytic activity for oxygen reduction of E2 is superior to that of E1 and E3. Membrane electrode assemblies (MEAs) containing the synthesized CoOx/C cathode catalysts were fabricated and evaluated by single cell tests. The E2 cathode performed better than that of E1 and E3 cathode. This can be attributed to the enhanced activity for ORR, in agreement with the composition of the catalyst that CoO co-existed with Co3O4. The maximum power density 73 mW cm-2 was obtained at 0.3 V with a current density of 240 mA cm-2 for E2 and the normalized power density of E2 is larger than that that of commercial 20 wt.% Pt/C-ETEK. -- Highlights: → Non-noble catalysts have been attracting increasing attention due to become a low-cost alternative catalyst for oxygen reduction in PEMFC. → This method for the production of nanoparticle cobalt oxides which can be incorporated into Vulcan XC-72

  13. Electrolyte Assisted Sono-Electrochemical Decomposition of Reactive Red 195

    International Nuclear Information System (INIS)

    Untreated textile wastewater causes serious environmental impacts due to the presence of unfixed dyes. A commonly used Reactive Red (RR) 195 dye is significantly discharged in textile effluents thus enhancing water pollution. Therefore, the current research was conducted for the treatment of reactive dye RR 195 by electrolyte assisted electrochemical process at various process conditions i.e, initial dye concentrations, pH, and concentration of supporting electrolyte (NaCl). The decomposition of dye and color removal was analyzed using UV-Vis spectrophotometer. The results indicated that pH and NaCl were playing an important role in the degradation of RR 195. It was observed that 95.4% of dye was decomposed using 1.5 g/L NaCl at pH 3 after 25 min. Kinetics studies showed that degradation of RR195 apparently followed second order reaction. The electrical energy consumption was found to be 6.11 Whm/sup -3/ for dye effluent at 100 Am/sup -2/ current density. For the justification of findings in experimental results Bayesian regression analysis was used to determine the effect of NaCl, pH and dye concentration on degeneration of RR195. It was observed that NaCl had positive impact whereas pH and dye concentration had negative impact on degeneration of RR195. (author)

  14. 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.

  15. Performance of Lithium Polymer Cells with Polyacrylonitrile based Electrolyte

    DEFF Research Database (Denmark)

    Perera, Kumudu; Dissanayake, M.A.K.L.; Skaarup, Steen;

    2006-01-01

    The performance of lithium polymer cells fabricated with Polyacrylonitrile (PAN) based electrolytes was studied using cycling voltammetry and continuous charge discharge cycling. The electrolytes consisted of PAN, ethylene carbonate (EC), propylene carbonate (PC) and lithium trifluoromethanesulfo...

  16. 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

  17. High temperature polymer electrolyte membrane fuel cell

    Institute of Scientific and Technical Information of China (English)

    K.Scott; M. Mamlouk

    2006-01-01

    One of the major issues limiting the introduction of polymer electrolyte membrane fuel cells (PEMFCs) is the low temperature of operation which makes platinum-based anode catalysts susceptible to poisoning by the trace amount of CO, inevitably present in reformed fuel. In order to alleviate the problem of CO poisoning and improve the power density of the cell, operating at temperature above 100 ℃ is preferred. Nafion(R) -type perfluorosulfonated polymers have been typically used for PEMFC. However, the conductivity of Nafion(R) -type polymers is not high enough to be used for fuel cell operations at higher temperature ( > 90 ℃) and atmospheric pressure because they dehydrate under these condition.An additional problem which faces the introduction of PEMFC technology is that of supplying or storing hydrogen for cell operation,especially for vehicular applications. Consequently the use of alternative fuels such as methanol and ethanol is of interest, especially if this can be used directly in the fuel cell, without reformation to hydrogen. A limitation of the direct use of alcohol is the lower activity of oxidation in comparison to hydrogen, which means that power densities are considerably lower. Hence to improve activity and power output higher temperatures of operation are preferable. To achieve this goal, requires a new polymer electrolyte membrane which exhibits stability and high conductivity in the absence of liquid water.Experimental data on a polybenzimidazole based PEMFC were presented. A simple steady-state isothermal model of the fuel cell is also used to aid in fuel cell performance optimisation. The governing equations involve the coupling of kinetic, ohmic and mass transport. This paper also considers the advances made in the performance of direct methanol and solid polymer electrolyte fuel cells and considers their limitations in relation to the source and type of fuels to be used.

  18. Polymer electrolyte membrane assembly for fuel cells

    Science.gov (United States)

    Yen, Shiao-Ping S. (Inventor); Kindler, Andrew (Inventor); Yavrouian, Andre (Inventor); Halpert, Gerald (Inventor)

    2002-01-01

    An electrolyte membrane for use in a fuel cell can contain sulfonated polyphenylether sulfones. The membrane can contain a first sulfonated polyphenylether sulfone and a second sulfonated polyphenylether sulfone, wherein the first sulfonated polyphenylether and the second sulfonated polyphenylether sulfone have equivalent weights greater than about 560, and the first sulfonated polyphenylether and the second sulfonated polyphenylether sulfone also have different equivalent weights. Also, a membrane for use in a fuel cell can contain a sulfonated polyphenylether sulfone and an unsulfonated polyphenylether sulfone. Methods for manufacturing a membrane electrode assemblies for use in fuel cells can include roughening a membrane surface. Electrodes and methods for fabricating such electrodes for use in a chemical fuel cell can include sintering an electrode. Such membranes and electrodes can be assembled into chemical fuel cells.

  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. CO tolerance of polymer electrolyte fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Gubler, L.; Scherer, G.G.; Wokaun, A. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    Reformed methanol can be used as a fuel for polymer electrolyte fuel cells instead of pure hydrogen. The reformate gas contains mainly H{sub 2}, CO{sub 2} in the order of 20% and low levels of CO in the order of 100 ppm. CO causes severe voltage losses due to poisoning of the anode catalyst. The effect of CO on cell performance was investigated at different CO levels up to 100 ppm. Various options to improve the CO tolerance of the fuel cell were assessed thereafter, of which the injection of a few percents of oxygen into the fuel feed stream proved to be most effective. By mixing 1% of oxygen with hydrogen containing 100 ppm CO, complete recovery of the cell performance could be attained. (author) 2 figs., 2 tabs., 3 refs.

  1. Technical report on galvanic cells with fused-salt electrolytes

    Science.gov (United States)

    Cairns, E. J.; Crouthamel, C. E.; Fischer, A. K.; Foster, M. S.; Hesson, J. C.; Johnson, C. E.; Shimotake, H.; Tevebaugh, A. D.

    1969-01-01

    Technical report is presented on sodium and lithium cells using fused salt electrolytes. It includes a discussion of the thermally regenerative galvanic cell and the secondary bimetallic cell for storage of electricity.

  2. Solid-polymer-electrolyte fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Fuller, T.F.

    1992-07-01

    A transport model for polymer electrolytes is presented, based on concentrated solution theory and irreversible thermodynamics. Thermodynamic driving forces are developed, transport properties are identified and experiments devised. Transport number of water in Nafion 117 membrane is determined using a concentration cell. It is 1.4 for a membrane equilibrated with saturated water vapor at 25{degrees}C, decreases slowly as the membrane is dehydrated, and falls sharply toward zero as the water content approaches zero. The relation between transference number, transport number, and electroosmotic drag coefficient is presented, and their relevance to water-management is discussed. A mathematical model of transport in a solid-polymer-electrolyte fuel cell is presented. A two-dimensional membrane-electrode assembly is considered. Water management, thermal management, and utilization of fuel are examined in detail. The membrane separators of these fuel cells require sorbed water to maintain conductivity; therefore it is necessary to manage the water content in membranes to ensure efficient operation. Water and thermal management are interrelated. Rate of heat removal is shown to be a critical parameter in the operation of these fuel cells. Current-voltage curves are presented for operation on air and reformed methanol. Equations for convective diffusion to a rotating disk are solved numerically for a consolute point between the bulk concentration and the surface. A singular-perturbation expansion is presented for the condition where the bulk concentration is nearly equal to the consolute-point composition. Results are compared to Levich's solution and analysis.

  3. Solid-polymer-electrolyte fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Fuller, T.F.

    1992-07-01

    A transport model for polymer electrolytes is presented, based on concentrated solution theory and irreversible thermodynamics. Thermodynamic driving forces are developed, transport properties are identified and experiments devised. Transport number of water in Nafion 117 membrane is determined using a concentration cell. It is 1.4 for a membrane equilibrated with saturated water vapor at 25{degrees}C, decreases slowly as the membrane is dehydrated, and falls sharply toward zero as the water content approaches zero. The relation between transference number, transport number, and electroosmotic drag coefficient is presented, and their relevance to water-management is discussed. A mathematical model of transport in a solid-polymer-electrolyte fuel cell is presented. A two-dimensional membrane-electrode assembly is considered. Water management, thermal management, and utilization of fuel are examined in detail. The membrane separators of these fuel cells require sorbed water to maintain conductivity; therefore it is necessary to manage the water content in membranes to ensure efficient operation. Water and thermal management are interrelated. Rate of heat removal is shown to be a critical parameter in the operation of these fuel cells. Current-voltage curves are presented for operation on air and reformed methanol. Equations for convective diffusion to a rotating disk are solved numerically for a consolute point between the bulk concentration and the surface. A singular-perturbation expansion is presented for the condition where the bulk concentration is nearly equal to the consolute-point composition. Results are compared to Levich`s solution and analysis.

  4. Cell-Assisted Lipotransfer

    DEFF Research Database (Denmark)

    Toyserkani, Navid Mohamadpour; Quaade, Marlene Louise; Sørensen, Jens Ahm

    2016-01-01

    -derived stromal cells (ASCs) to enrich the fat graft, a procedure termed cell-assisted lipotransfer (CAL). The aim of this review was to systematically review the current preclinical and clinical evidence for the efficacy of CAL compared with conventional lipotransfer. MATERIALS AND METHODS: A systematic search....... CONCLUSIONS: The present evidence suggests that there is a big potential for CAL in reconstructive surgery; however, the present studies are so far still of low quality with inherent weaknesses. Several aspects regarding CAL still remain unknown such as the optimal degree of cell enrichment and also its...

  5. Discharging dynamics in an electrolytic cell.

    Science.gov (United States)

    Feicht, Sarah E; Frankel, Alexandra E; Khair, Aditya S

    2016-07-01

    We analyze the dynamics of a discharging electrolytic cell comprised of a binary symmetric electrolyte between two planar, parallel blocking electrodes. When a voltage is initially applied, ions in the electrolyte migrate towards the electrodes, forming electrical double layers. After the system reaches steady state and the external current decays to zero, the applied voltage is switched off and the cell discharges, with the ions eventually returning to a uniform spatial concentration. At voltages on the order of the thermal voltage V_{T}=k_{B}T/q≃25 mV, where k_{B} is Boltzmann's constant, T is temperature, and q is the charge of a proton, experiments on surfactant-doped nonpolar fluids observe that the temporal evolution of the external current during charging and discharging is not symmetric [V. Novotny and M. A. Hopper, J. Electrochem. Soc. 126, 925 (1979)JESOAN0013-465110.1149/1.2129195; P. Kornilovitch and Y. Jeon, J. Appl. Phys. 109, 064509 (2011)JAPIAU0021-897910.1063/1.3554445]. In fact, at sufficiently large voltages (several V_{T}), the current during discharging is no longer monotonic: it displays a "reverse peak" before decaying in magnitude to zero. We analyze the dynamics of discharging by solving the Poisson-Nernst-Planck equations governing ion transport via asymptotic and numerical techniques in three regimes. First, in the "linear regime" when the applied voltage V is formally much less than V_{T}, the charging and discharging currents are antisymmetric in time; however, the potential and charge density profiles during charging and discharging are asymmetric. The current evolution is on the RC timescale of the cell, λ_{D}L/D, where L is the width of the cell, D is the diffusivity of ions, and λ_{D} is the Debye length. Second, in the (experimentally relevant) thin-double-layer limit ε=λ_{D}/L≪1, there is a "weakly nonlinear" regime defined by V_{T}≲V≲V_{T}ln(1/ε), where the bulk salt concentration is uniform; thus the RC timescale of

  6. Zirconium pyrophosphate matrix layer for electrolyte in a fuel cell

    International Nuclear Information System (INIS)

    A fuel cell is described comprising: (a) a pair of spaced apart electrodes; (b) a porous electrolyte retaining matrix layer disposed between the electrodes, and matrix layer comprising particles of a zirconium compound, wherein the zirconium compound consists essentially of ZrP/sub 2/O/sub 7/; and (c) electrolyte contained within the matrix layer

  7. Altered Membrane Potential and Electrolyte in Sickle Cell Anemia

    Directory of Open Access Journals (Sweden)

    JK Nnodim

    2014-01-01

    Full Text Available Aim: This study has been to evaluate the level of membrane potential and electrolyte in sickle cell disease patients. Material and methods: 100 sickle cell patients in steady state ages 5 to 30 years attending General Hospital Owerri were used in the study while 100 normal subjects (HbAA were used as control. Also 30 HbSS in crisis have been involved. Results: The results obtained showed that the level of membrane potential was significantly lower in sickle cell anemia as compared to the controls. Also, the level of the electrolyte was found significantly decreased in HbSS when compared with HbAA at P<0.05. Conclusion: The membrane potential translates to energy which means that there is less energy in sickle cell disease which is linked to electrolyte imbalance. Hence people with sickle disease should be monitored closely for their electrolytes to avoid crisis.

  8. Low temperature electrolytes for lithium/silver vanadium oxide cells

    Science.gov (United States)

    Tuhovak, Denise R.; Takeuchi, Esther S.

    1991-01-01

    Combinations of methyl formate (MF) and propylene carbonate (PC) using salt concentrations of 0.6 to 2.4 M, with lithium hexafluoroarsenate and lithium tetrafluoroborate in a five to one molar ratio, were investigated as electrolytes in lithium/silver vanadium oxide batteries. The composition of the electrolyte affected cell performance at low temperature, self-discharge and abuse resistance as characterized by short circuit and crush testing. The electrolyte that provided the best combination of good low temperature performance, low cell self-discharge and abuse resistance was 0.6 M salt in 10:90 PC/MF.

  9. Fuel cells with solid polymer electrolyte and their application on vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Fateev, V.

    1996-04-01

    In Russia, solid polymer electrolyte MF-4-SK has been developed for fuel cells. This electrolyte is based on perfluorinated polymer with functional sulfogroups. Investigations on electrolyte properties and electrocatalysts have been carried out.

  10. Electrochemical Synthesis of Ammonia in Solid Electrolyte Cells

    OpenAIRE

    MichaelStoukides

    2014-01-01

    Developed in the early 1900s, the “Haber–Bosch” synthesis is the dominant NH3 synthesis process. Parallel to catalyst optimization, current research efforts are also focused on the investigation of new methods for ammonia synthesis, including the electrochemical synthesis with the use of solid electrolyte cells. Since the first report on Solid State Ammonia Synthesis (SSAS), more than 30 solid electrolyte materials were tested and at least 15 catalysts were used as working electrodes. Thus fa...

  11. Electrode structures of polymer-electrolyte fuel cells (PEFC). An electron microscopy approach to the characterization of the electrode structure of polymer electrolyte fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Scheiba, Frieder

    2009-01-28

    Polymer electrolyte fuel cells (PEFC) have a complex electrode structure, which usually consists of a catalyst, a catalyst support, a polymer electrolyte and pores. The materials used are largely amorphous, have a strong defective structure or have particle diameter of only a few nanometers. In the electrode the materials form highly disordered aggregated structures. Both aspects complicate a systematic structural analysis significantly. However, thorough knowledge of the electrode structure, is needed for systematic advancement of fuel cell technology and to obtain a better understanding of mass and charge carrier transport processes in the electrode. Because of the complex structure of the electrode, an approach based on the examination of electrode thin-sections by electron microscopy was chosen in this work to depicting the electrode structure experimentally. The present work presents these studies of the electrode structure. Some fundamental issues as the influence of the polymer electrolyte concentration and the polarity of the solvent used in the electrode manufacturing process were addressed. During the analysis particular attention was payed to the distribution and structure of the polymer electrolyte. A major problem to the investigations, were the low contrast between the polymer electrolyte, the catalyst support material and the embedding resin. Therefore, dilerent techniques were investigated in terms of their ability to improve the contrast. In this context, a computer-assisted acquisition procedure for energy filtered transmission electron microscopy (EF-TEM) was developed. The acquisition procedure permits a significant extension of the imageable sample. At the same time, it was possible to substantially reduce beam damage of the specimen and to minimize drift of the sample considerably. This allowed unambiguous identification of the polymer electrolyte in the electrode. It could further be shown, that the polymer electrolyte not only coats the

  12. Common Student Misconceptions in Electrochemistry: Galvanic, Electrolytic, and Concentration Cells.

    Science.gov (United States)

    Sanger, Michael J.; Greenbowe, Thomas J.

    1997-01-01

    Investigates student (N=16) misconceptions concerning electrochemistry related to galvanic, electrolytic, and concentration cells. Findings indicate that most students demonstrating misconceptions were still able to calculate cell potentials correctly. Discusses common misconceptions and possible sources of these. Contains 33 references.…

  13. Matrix member for containing fuel cell acid electrolyte

    International Nuclear Information System (INIS)

    A matrix member for carrying the acid electrolyte of a fuel cell comprised of a first layer containing a carbon material and a second layer containing a silicon carbide material. A further matrix member is disclosed wherein the mean pore size of the member is substantially equal to or less than that mean pore size of at least one of the fuel cell electrodes

  14. Potential electrode/electrolyte interactions in solid oxide fuel cells

    International Nuclear Information System (INIS)

    Yttria-stabilized zirconia and strontium-doped lanthanum manganite are the prime candidates for the electrolyte and the air electrode material, respectively, for the solid oxide fuel cell. In this study, the potential high temperature interactions, including intrinsic reactivity and interdiffusion, between these two fuel cell components have been investigated

  15. 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)

  16. Alkaline polymer electrolyte fuel cells: Principle, challenges, and recent progress

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Polymer electrolyte membrane fuel cells (PEMFC) have been recognized as a significant power source in future energy systems based on hydrogen. The current PEMFC technology features the employment of acidic polymer electrolytes which, albeit superior to electrolyte solutions, have intrinsically limited the catalysts to noble metals, fundamentally preventing PEMFC from widespread deployment. An effective solution to this problem is to develop fuel cells based on alkaline polymer electrolytes (APEFC), which not only enable the use of non-precious metal catalysts but also avoid the carbonate-precipitate issue which has been troubling the conventional alkaline fuel cells (AFC). This feature article introduces the principle of APEFC, the challenges, and our research progress, and focuses on strategies for developing key materials, including high-performance alkaline polyelectrolytes and stable non-precious metal catalysts. For alkaline polymer electrolytes, high ionic conductivity and satisfactory mechanical property are difficult to be balanced, therefore polymer cross-linking is an ultimate strategy. For non-precious metal catalysts, it is urgent to improve the catalytic activity and stability. New materials, such as transition-metal complexes, nitrogen-doped carbon nanotubes, and metal carbides, would become applicable in APEFC.

  17. Cathode degradation of the polymer electrolyte membrane fuel cell (PEMFC)

    International Nuclear Information System (INIS)

    Morphological changes occurring in membrane electrode assemblies (MEAs) of polymer electrolyte membrane fuel cells (PEMFC's) were monitored using scanning microscopy (SEM) during the course of 600 hours testing of hydrogen/air polymer electrolyte fuel cells (PEFCs). The microstructural study suggests a structural change caused by loss of the recast ionomer could result in deterioration of the integrity of the electrode, a drop in both ionic and electronic conductivities, loss of platinum particle clusters (for carbon support), and increased resistance within the interfacial zone of the membrane and catalyst layer.(author)

  18. Magnesia nanoparticles in liquid electrolyte for dye sensitized solar cells: An effective recombination suppressant?

    International Nuclear Information System (INIS)

    Highlights: ► MgO loaded electrolyte retards recombination at titania/electrolyte interface. ► Recombination reactions are retarded by adsorption of anions on MgO in electrolyte. ► Zeta potential measurements show anionic adsorption on the surface of MgO. ► MgO loaded electrolyte performs efficiently than TBP containing electrolyte. -- Abstract: Recombination reactions at the photoanode/electrolyte interface reduce the photovoltaic conversion efficiency of dye sensitized solar cells (DSSCs). Unlike modification of titania photoanode by coating with MgO which act as a barrier layer toward recombination, addition of MgO nanopowder to electrolyte prevents recombination through adsorption of anions (triiodide/iodide) from electrolyte. In the present study, the surface charge of MgO has been utilized to adsorb anions from electrolyte. This anionic adsorption onto the MgO nanopowders in electrolyte has been confirmed by zeta potential measurements. MgO retards the recombination reaction as efficiently as 4-tert-butylpyridine (TBP) which is the most widely used additive in the electrolyte. Higher photocurrent and conversion efficiency is achieved by using MgO loaded electrolyte as compared to TBP added electrolyte. Dark current measurements show that recombination reactions are effectively retarded by use of MgO loaded electrolytes. Open circuit voltage decay measurements also confirm higher electron lifetime at the titania/electrolyte interface in MgO loaded electrolyte based cell as compared to additive free electrolyte based cell

  19. The Stirred Tank Reactor Polymer Electrolyte Membrane Fuel Cell

    OpenAIRE

    Benziger, Jay; Chia, E.; Karnas, E.; Moxley, J.; Teuscher, C.; Kevrekidis, I. G.

    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 S...

  20. Non-aqueous electrolytes for electrochemical cells

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Jian; Zhang, Zhengcheng; Amine, Khalil

    2016-07-12

    A electrolyte for a lithium battery includes a silane/siloxane compound represented by SiR.sub.4-x-yR'.sub.xR''.sub.y, by Formula II, or Formula III: ##STR00001## where each R is individually an alkenyl, alkynyl, alk(poly)enyl, alk(poly)ynyl, aryl; each R' is represented by; ##STR00002## each R'' is represented by Formula I-B; ##STR00003## R.sup.1 is an organic spacer; R.sup.2 is a bond or an organic spacer; R.sup.3 is alkyl or aryl; k is 1-15; m is 1-15; n is 1 or 2; p is 1-3; x' is 1-2; and y' is 0-2.

  1. Toughness of membranes applied in polymer electrolyte fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Kiefer, J.; Brack, H.P.; Scherer, G.G. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    Since several years we apply the radiation-grafting technique to prepare polymeric membranes for application in polymer electrolyte fuel cells (PEFCs). Our investigations presented here focus on changes in toughness of these materials after the various synthesis steps and the importance of membrane toughness for their application in PEFCs. (author) 2 figs., 4 refs.

  2. Improved Electrodes and Electrolytes for Dye-Based Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Harry R. Allcock; Thomas E. Mallouk; Mark W. Horn

    2011-10-26

    The most important factor in limiting the stability of dye-sensitized solar cells is the use of volatile liquid solvents in the electrolytes, which causes leakage during extended operation especially at elevated temperatures. This, together with the necessary complex sealing of the cells, seriously hampers the industrial-scale manufacturing and commercialization feasibilities of DSSCs. The objective of this program was to bring about a significant improvement in the performance and longevity of dye-based solar cells leading to commercialization. This had been studied in two ways first through development of low volatility solid, gel or liquid electrolytes, second through design and fabrication of TiO2 sculptured thin film electrodes.

  3. Electrochemical Synthesis of Ammonia in Solid Electrolyte Cells

    Directory of Open Access Journals (Sweden)

    MichaelStoukides

    2014-01-01

    Full Text Available Developed in the early 1900's, the “Haber-Bosch” synthesis is the dominant NH3 synthesis process. Parallel to catalyst optimization, current research efforts are also focused on the investigation of new methods for ammonia synthesis, including the electrochemical synthesis with the use of solid electrolyte cells. Since the first report on Solid State Ammonia Synthesis (SSAS, more than 30 solid electrolyte materials were tested and at least 15 catalysts were used as working electrodes. Thus far, the highest rate of ammonia formation reported is 1.13×10−8 mol s−1 cm−2, obtained at 80°C with a Nafion solid electrolyte and a mixed oxide, SmFe0.7Cu0.1Ni0.2O3, cathode. At high temperatures (>500oC the maximum rate was 9.5*10-9 mol s−1 cm−2 using Ce0.8Y0.2O2-δ -[Ca3(PO42 -K3PO4] as electrolyte and Ag-Pd as cathode. In this paper, the advantages and the disadvantages of SSAS vs the conventional process and the requirements that must be met in order to promote the electrochemical process into an industrial level, are discussed.

  4. The Autohumidification Polymer Electrolyte Membrane Fuel Cell

    CERN Document Server

    Benziger, J B; Tulyani, S; Turner, A; Bocarsly, A B; Kevrekidis, Yu G

    2003-01-01

    A PEM fuel cell was specially constructed to determine kinetics under conditions of well-defined gas phase composition and cell temperature. Steady state multiplicity was discovered in the autohumidification PEM fuel cell, resulting from a balance between water production and water removal. Ignition was observed in the PEM fuel cell for a critical water activity of about 0.1. Ignition is a consequence of the exponential increase of proton conductivity with water activity, which creates an autocatalytic feedback between the water production and the proton conduction. The steady state current in the ignited state decreases with increasing temperature between 50 to 105 deg C. At temperatures greater than 70 deg C five steady states were observed in the PEM fuel cell. The steady state performance has been followed with variable load resistance and hysteresis loops have been mapped. The dynamics of transitions between steady states are slow about 10^3 to 10^4 s. These slow dynamics are suggested to result from a c...

  5. 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...

  6. Progress on the Electrolytes for Dye-sensitized Solar Cells

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    1 Results The development of a new type of solar cell has been promoted by public concern about pollution and energy consumption.Since the prototype of a dye-sensitized solar cell (DSC) was reported in 1991 by M.Gratzel,it has aroused intensive interest over the past decade due to its low cost and simple preparation procedure.The typical cell is a sandwiched structure consisting of a dye-sensitized TiO2 electrode,a platinized counter electrode and a filled redox couple electrolyte between the electrodes...

  7. Polymer electrolyte fuel cells: flow field for efficient air operation

    Energy Technology Data Exchange (ETDEWEB)

    Buechi, F.N.; Tsukada, A.; Haas, O.; Scherer, G.G. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    A new flow field was designed for a polymer electrolyte fuel cell stack with an active area of 200 cm{sup 2} for operation at low air stoichiometry and low air over pressure. Optimum of gas flow and channel dimensions were calculated based on the required pressure drop in the fluid. Single cells and a bi-cell stack with the new flow field show an improved current/voltage characteristic when operated at low air stoichiometries as compared to that of the previous non optimized design. (author) 4 figs., 3 refs.

  8. Polymer electrolyte fuel cells physical principles of materials and operation

    CERN Document Server

    Eikerling, Michael

    2014-01-01

    The book provides a systematic and profound account of scientific challenges in fuel cell research. The introductory chapters bring readers up to date on the urgency and implications of the global energy challenge, the prospects of electrochemical energy conversion technologies, and the thermodynamic and electrochemical principles underlying the operation of polymer electrolyte fuel cells. The book then presents the scientific challenges in fuel cell research as a systematic account of distinct components, length scales, physicochemical processes, and scientific disciplines. The main part of t

  9. Electrolytes For Intermediate Temperature Solid Oxide Fuel Cells

    Directory of Open Access Journals (Sweden)

    Rękas M.

    2015-06-01

    Full Text Available Solid electrolytes for construction of the intermediate-temperature solid oxide fuel cells, IT-SOFC, have been reviewed. Yttrium stabilized tetragonal zirconia polycrystals, YTZP, as a potential electrolyte of IT-SOFC have been highlighted. The experimental results involving structural, microstructural, electrical properties based on our own studies were presented. In order to study aluminum diffusion in YTZP, aluminum oxide was deposited on the surface of 3 mol.% yttria stabilized tetragonal zirconia polycrystals (3Y-TZP. The samples were annealed at temperatures from 1523 to 1773 K. Diffusion profiles of Al in the form of mean concentration vs. depth in B-type kinetic region were investigated by secondary ion mass spectroscopy (SIMS. Both the lattice (DB and grain boundary (DGB diffusion were determined.

  10. Perovskite solid electrolytes: Structure, transport properties and fuel cell applications

    DEFF Research Database (Denmark)

    Bonanos, N.; Knight, K.S.; Ellis, B.

    1995-01-01

    Doped barium cerate perovskites, first investigated by Iwahara and co-workers, have ionic conductivities of the order of 20 mS/cm at 800 degrees C making them attractive as fuel cell electrolytes for this temperature region. They have been used to construct laboratory scale fuel cells, which, in...... addition to performance data, have provided an unexpected insight into the transport processes operating in these materials. In the temperature range of 600-1000 degrees C, the dominant transport process varies from protonic to oxide-ion dominated. This transition has been confirmed by measurement of water...

  11. Cold-start characteristics of polymer electrolyte fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Mishler, Jeff [Los Alamos National Laboratory; Mukundan, Rangachary [Los Alamos National Laboratory; Wang, Yun [UNIV. CAL. RIVERSIDE; Mishler, Jeff [UNIV. CAL. RIVERSIDE; Mukherjee, Partha P [ORNL

    2010-01-01

    In this paper, we investigate the electrochemical reaction kinetics, species transport, and solid water dynamics in a polymer electrolyte fuel cell (PEFC) during cold start. A simplitied analysis is developed to enable the evaluation of the impact of ice volume fraction on cell performance during coldstart. Supporting neutron imaging data are also provided to reveal the real-time water evolution. Temperature-dependent voltage changes due to the reaction kinetics and ohmic loss are also analyzed based on the ionic conductivity of the membrane at subfreezing temperature. The analysis is valuable for the fundamental study of PEFC cold-start.

  12. Polybenzimidazoles based on high temperature polymer electrolyte fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Linares Leon, Jose Joaquin; Camargo, Ana Paula M.; Ashino, Natalia M.; Morgado, Daniella L.; Frollini, Elisabeth; Paganin, Valdecir A.; Gonzalez, Ernesto Rafael [Universidade de Sao Paulo (IQSC/USP), Sao Carlos, SP (Brazil); Bajo, Justo Lobato [University of Castilla-La Mancha, Ciudad Real (Spain). Dept. of Chemical Engineering

    2010-07-01

    This work presents an interesting approach in order to enhance the performance of Polymer Electrolyte Membrane Fuel Cells (PEMFC) by means of an increase in the operational temperature. For this, two polymeric materials, Poly(2,5-bibenzimidazole) (ABPBI) and Poly[2,2'-(m-phenyl en)-5,5' bib enzimidazol] (PBI), impregnated with phosphoric acid have been utilized. These have shown excellent properties, such as thermal stability above 500 deg C, reasonably high conductivity when impregnated with H{sub 3}PO{sub 4} and a low permeability to alcohols compared to Nafion. Preliminary fuel cells measurements on hydrogen based Polymer Electrolyte Membrane Fuel Cell (PEMFC) displayed an interestingly reasonable good fuel cell performance, a quite reduced loss when the hydrogen stream was polluted with carbon monoxide, and finally, when the system was tested with an ethanol/water (E/W) fuel, it displayed quite promising results that allows placing this system as an attractive option in order to increase the cell performance and deal with the typical limitations of low temperature Nafion-based PEMFC. (author)

  13. 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.

  14. Integration of polymer electrolytes in dye sensitized solar cells by initiated chemical vapor deposition

    International Nuclear Information System (INIS)

    The mesoporous titanium dioxide electrode of dye sensitized solar cells (DSSC) has been successfully filled with polymer electrolyte to replace the conventional liquid electrolyte. Polymer electrolyte was directly synthesized and deposited using the initiated chemical vapor deposition (iCVD) process, and an iodide-triiodide redox couple in different redox solvents was then incorporated into the polymer. We have investigated different candidate polymer electrolytes, including poly(2-hydroxyethyl methacrylate) (PHEMA). The open circuit voltage of cells fabricated with iCVD PHEMA was found to be higher when compared with a liquid electrolyte that is attributed to a lower rate of electron recombination.

  15. Cleaning of used cathode and board units of electrolytic cells by acid method

    International Nuclear Information System (INIS)

    Present article is devoted to cleaning of used cathode and board units of electrolytic cells by acid method. The studies results on setting of optimal parameters of extraction of extrinsic components remain after aqueous treatment of used cathode and board units of electrolytic cells of aluminium production were considered. It was defined that with using of 10% of hydrochloric acid solution from used cathode and board units of electrolytic cells it is possible to obtain the purified carbon-graphite material.

  16. Electrode Architecture in Galvanic and Electrolytic Energy Cells.

    Science.gov (United States)

    Jeong, Beomgyun; Ocon, Joey D; Lee, Jaeyoung

    2016-04-11

    Electrodes in galvanic and electrolytic energy cells are complicated structures comprising redox-active materials, ionic/electronic conductors, and porous pathways for mass transfer of reactants. In contrast to breakthroughs in component development, methods of optimizing whole-system architectural design to draw maximum output have not been well explored. In this Minireview, we introduce generalized types of electrode architecture, discuss fabrication strategies, and characterize already built structures. Systematic efforts to discover optimal electrode configurations will resolve long-standing discrepancies that arise between whole systems and the sums of their parts for a number of electrochemical reactions and technologies. PMID:26938667

  17. Perovskite solid electrolytes: Structure, transport properties and fuel cell applications

    DEFF Research Database (Denmark)

    Bonanos, N.; Knight, K.S.; Ellis, B.

    1995-01-01

    addition to performance data, have provided an unexpected insight into the transport processes operating in these materials. In the temperature range of 600-1000 degrees C, the dominant transport process varies from protonic to oxide-ion dominated. This transition has been confirmed by measurement of water...... vapour transfer in a cell in which the perovskite is exposed to wet hydrogen on both sides. The evolution of transport properties with temperature is discussed in relation to structure. Neutron diffraction studies of doped and undoped barium cerate are reported, revealing a series of phase transitions......Doped barium cerate perovskites, first investigated by Iwahara and co-workers, have ionic conductivities of the order of 20 mS/cm at 800 degrees C making them attractive as fuel cell electrolytes for this temperature region. They have been used to construct laboratory scale fuel cells, which, in...

  18. Membrane-based electrolyte sheets for facile fabrication of flexible dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Highlights: → A new electrolyte sheet was developed for flexible dye-sensitized solar cells (DSCs). → It is composed of a porous polyethylene membranes and ionic liquid electrolytes. → The electrochemical properties of the electrolyte sheets were evaluated. → High-performance flexible DSCs with the electrolyte sheets were facilely fabricated. - Abstract: New electrolyte sheets based on porous polyethylene membranes for flexible dye-sensitized solar cells have been developed. Ionic liquid electrolytes are accommodated in commercial polyethylene membranes to form the electrolyte sheets. The morphology of membranes and iodine concentrations in ionic liquid are varied. The electrochemical measurement results show that the morphology, pore structure, and iodine concentration affect mass transport in electrolyte sheet, as well as charge transfer between platinum electrode and electrolyte sheet greatly. Based on these electrolyte sheets, lamination method instead of conventional vacuum injection of electrolyte is used to fabricate flexible dye-sensitized solar cells. Optimal device with an open-circuit voltage (Voc) of 0.63 V, a fill factor of 0.58, and a short-circuit current density (Jsc) of 6.17 mA cm-2 at an incident light intensity of 100 mW cm-2 is obtained, which yields a light-to-electricity conversion efficiency of 2.25%.

  19. Microstructured Electrolyte Membranes to Improve Fuel Cell Performance

    Science.gov (United States)

    Wei, Xue

    Fuel cells, with the advantages of high efficiency, low greenhouse gas emission, and long lifetime are a promising technology for both portable power and stationary power sources. The development of efficient electrolyte membranes with high ionic conductivity, good mechanical durability and dense structure at low cost remains a challenge to the commercialization of fuel cells. This thesis focuses on exploring novel composite polymer membranes and ceramic electrolytes with the microstructure engineered to improve performance in direct methanol fuel cells (DMFCs) and solid oxide fuel cells (SOFCs), respectively. Polymer/particle composite membranes hold promise to meet the demands of DMFCs at lower cost. The structure of composite membranes was controlled by aligning proton conducting particles across the membrane thickness under an applied electric field. The field-induced structural changes caused the membranes to display an enhanced water uptake, proton conductivity, and methanol permeability in comparison to membranes prepared without an applied field. Although both methanol permeability and proton conductivity are enhanced by the applied field, the permeability increase is relatively lower than the proton conductivity improvement, which results in enhanced proton/methanol selectivity and improved DMFC performance. Apatite ceramics are a new class of fast ion conductors being studied as alternative SOFC electrolytes in the intermediate temperature range. An electrochemical/hydrothermal deposition method was developed to grow fully dense apatite membranes containing well-developed crystals with c-axis alignment to promote ion conductivity. Hydroxyapatite seed crystals were first deposited onto a metal substrate electrochemically. Subsequent ion substitution during the hydrothermal growth process promoted the formation of dense, fully crystalline films with microstructure optimal for ion transport. The deposition parameters were systematically investigated, such as

  20. 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.

  1. Exegoeconomic Analysis On A Proton Electrolyte Membrane Fuel Cell

    International Nuclear Information System (INIS)

    The objective of this study is to perform an exergy and economic analysis on proton electrolyte membrane fuel cell power system (PEMFC) known as exegoeconomic. A 5 kW PEMFC was taken as case study. The fuel cell includes the hydrogen processing system and a fuel cell stack. The hydrogen processing system consisted of an auto-thermal reactor (ATR), a water gas shift reactor (WGS), tubular ceramic membrane module (TCR) and a pressure swing adsorber (PSA). The fuel cell stack was the main power generator. It was obseved that TCM and PSA have low energy efficiency of 0.29 % and 0.09 % respectively. Energy efficiency for the auto-thermal reactor and fuel cell stack were higher at 22.44 % and 31.97 % respectively and both values are comparable with other studies. The exergoeconomics for the 5kW fuel cell system was determined as RM4756.62 per GJ. From the analysis, it is also found that the fuel cell cost can more competitive, if the cost of operation, maintenance and fuel can be reduced. (author)

  2. Bipolar switching polarity reversal by electrolyte layer sequence in electrochemical metallization cells with dual-layer solid electrolytes.

    Science.gov (United States)

    Soni, Rohit; Meuffels, Paul; Petraru, Adrian; Hansen, Mirko; Ziegler, Martin; Vavra, Ondrej; Kohlstedt, Hermann; Jeong, Doo Seok

    2013-12-21

    Bipolar switching behaviours of electrochemical metallization (ECM) cells with dual-layer solid electrolytes (SiOx-Ge0.3Se0.7) were analyzed. Type 1 ECM cell, Pt (bottom electrode)/SiOx/Ge0.3Se0.7/Cu (top electrode), exhibited typical eightwise current-voltage (I-V) hysteresis of ECM cells whereas Type 2 ECM cell, Pt (bottom electrode)/Ge0.3Se0.7/SiOx/Cu(top electrode), showed counter-eightwise hysteresis. In addition, absolute off-switching voltage in Type 2 cell is lower than that in Type 1 cell while on-switching voltage in both cells is almost the same. An attempt to understand this electrolyte-stack-sequence-depending switching polarity reversal was made in terms of the ECM cell potential change upon the electrolyte stack sequence and the consequent change in Cu filament growth direction. Relevant experimental evidence for the hypothesis was obtained regarding the switching behaviours. Furthermore, given the switching polarity reversal, feasibility of serial complementary resistive switches was also demonstrated. PMID:24177268

  3. A new type quasi-solid state electrolyte for dye-sensitized solar cells

    Institute of Scientific and Technical Information of China (English)

    WANG Miao; YANG Lei; ZHOU Xiaowen; LIN Yuan; LI Xueping; FENG Shujing; XIAO Xurui

    2006-01-01

    A new type quasi-solid state electrolyte was prepared by solidifying liquid electrolytes containing organic solvents (such as mixture of ethylene carbonate (EC) and propylene carbonate (PC), 3-methoxypropinitrile (NMP) and N-methyl-oxazolidinone (NMO)) with comb-like molten salt type polymer,and was for the first time employed in dyesensitized solar cells (DSSCs). The optimal electrolyte composition was obtained by regulating the polymer content in the electrolytes and optimizing performance data of the electrolytes and assembled cells, yielding a maximum conversion efficiency of 6.58% (AM 1.5,100 mW.cm-2). Furthermore, the existence of this new type polymer in the electrolyte suppresses the evaporation of organic solvent and improves the stability of the cells.

  4. Effect of electromagnetic force and anode gas on electrolyte flow in aluminum electrolysis cell

    Institute of Scientific and Technical Information of China (English)

    ZHOU Nai-jun; XIA Xiao-xia; BAO Sheng-zhong

    2006-01-01

    Based on the commercial computational fluid dynamics software CFX-4.3, electrolyte flow fields in a 156 kA pre-baked anode aluminum electrolysis cell were investigated in three different cases where the electrolyte melt was driven by different kinds of force, i.e. electromagnetic force only, the anode gas drag force only and both of the former two forces. The results show that when electromagnetic force was introduced only, most of the electrolyte moves horizontally; when anode gas drag force was introduced only, the electrolyte flows mainly around each anode with small circulation; when electromagnetic force and anode gas drag force were both introduced together, the structure of the electrolyte flow fields and the velocity of electrolyte are similar to that of the case where only anode gas drag force is used. The electrolyte flow fields are mainly determined by the anode gas drag force.

  5. A quasi-direct methanol fuel cell system based on blend polymer membrane electrolytes

    DEFF Research Database (Denmark)

    Li, Qingfeng; Hjuler, Hans Aage; Hasiotis, C.;

    2002-01-01

    On the basis of blend polymer electrolytes of polybenzimidazole and sulfonated polysulfone, a polymer electrolyte membrane fuel cell was developed with an operational temperature up to 200degrees C. Due to the high operational temperature, the fuel cell can tolerate 1.0-3.0 vol % CO in the fuel...

  6. PREPARATION AND CHARACTERIZATION OF SOLID ELECTROLYTES: FUEL CELL APPLICATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Rambabu Bobba; Josef Hormes; T. Wang; Jaymes A. Baker; Donald G. Prier; Tommy Rockwood; Dinesha Hawkins; Saleem Hasan; V. Rayanki

    1997-12-31

    Electrolytes. Ionically conducting solid electrolytes are successfully used for battery, fuel cell and sensor applications.

  7. Membrane electrode assemblies for unitised regenerative polymer electrolyte fuel cells

    Science.gov (United States)

    Wittstadt, U.; Wagner, E.; Jungmann, T.

    Membrane electrode assemblies for regenerative polymer electrolyte fuel cells were made by hot pressing and sputtering. The different MEAs are examined in fuel cell and water electrolysis mode at different pressure and temperature conditions. Polarisation curves and ac impedance spectra are used to investigate the influence of the changes in coating technique. The hydrogen gas permeation through the membrane is determined by analysing the produced oxygen in electrolysis mode. The analysis shows, that better performances in both process directions can be achieved with an additional layer of sputtered platinum on the oxygen electrode. Thus, the electrochemical round-trip efficiency can be improved by more than 4%. Treating the oxygen electrode with PTFE solution shows better performance in fuel cell and less performance in electrolysis mode. The increase of the round-trip efficiency is negligible. A layer sputtered directly on the membrane shows good impermeability, and hence results in high voltages at low current densities. The mass transportation is apparently constricted. The gas diffusion layer on the oxygen electrode, in this case a titanium foam, leads to flooding of the cell in fuel cell mode. Stable operation is achieved after pretreatment of the GDL with a PTFE solution.

  8. 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.

  9. Highly durable and efficient quantum dot-sensitized solar cells based on oligomer gel electrolytes.

    Science.gov (United States)

    Kim, Heejin; Hwang, Insung; Yong, Kijung

    2014-07-23

    For stable quantum dot-sensitized solar cells, an oligomer-contained gel electrolyte was employed with a carbon-based counter electrode and a hierarchically shelled ZnO photoelectrode. Poly(ethylene glycol) dimethyl-ether (PEGDME) was added to the polysulfide electrolyte to enhance the stability of the methanol-based electrolyte. In addition, the nanocomposite gel electrolyte with fumed silica was used, which provided a solid three-dimensional network. A quantum-dot-modified ZnO nanowire photoanode enhanced the visible light harvesting, and a Pt/CNT-RGO counter electrode increased the catalytic activity. The oligomer gel electrolyte prevented the liquid electrolyte from leaking, and the carbon-based counter electrode retarded chemical poisoning at the counter electrode. The optimized cell exhibited 5.45% photoelectric conversion efficiency with long-term stability demonstrated over 5000 s operation time. PMID:24987930

  10. Preliminary study of application of Moringa oleifera resin as polymer electrolyte in DSSC solar cells

    Science.gov (United States)

    Saehana, Sahrul; Darsikin, Muslimin

    2016-04-01

    This study reports the preliminary study of application of Moringa oleifera resin as polymer electrolyte in dye-sensitized solar cell (DSSC). We found that polymer electrolyte membrane was formed by using solution casting methods. It is observed that polymer electrolyte was in elastic form and it is very potential to application as DSSC component. Performance of DSSC which employing Moringa oleifera resin was also observed and photovoltaic effect was found.

  11. Microfabricated polymer electrolyte membrane fuel cells with low catalyst loadings

    Energy Technology Data Exchange (ETDEWEB)

    Gruber, D.; Ponath, N.; Mueller, J. [Hamburg University of Technology, Hamburg (Germany). Department of Micro Systems Technology

    2005-11-01

    Miniaturized fuel cells as compact power sources fabricated in Pyrex glass using standard polymer electrolyte membrane (PEM) and electrode materials are presented. Photolithographic patterned and wet chemically etched serpentine flow channels of 1 mm in width and 250 {mu} m in depth transport the fuels to the cell of 1.44 cm{sup 2} active electrode area. Feeding H{sub 2}/O{sub 2} a maximum power density of 149 mW cm{sup -2} is attained at a very low Pt loading of 0.054 mg cm{sup -2}, ambient pressure, and room temperature. Operated with methanol and oxygen about 9 mW cm{sup -2} are achieved at ambient pressure, 60 C, and 1 mg cm{sup -2} PtRu/Pt (anode/cathode) loading. A planar two-cell stack to demonstrate and investigate the assembly of a fuel cell system on Pyrex wafers has successfully been fabricated. (author)

  12. Economics of Direct Hydrogen Polymer Electrolyte Membrane Fuel Cell Systems

    Energy Technology Data Exchange (ETDEWEB)

    Mahadevan, Kathyayani

    2011-10-04

    Battelle's Economic Analysis of PEM Fuel Cell Systems project was initiated in 2003 to evaluate the technology and markets that are near-term and potentially could support the transition to fuel cells in automotive markets. The objective of Battelle?s project was to assist the DOE in developing fuel cell systems for pre-automotive applications by analyzing the technical, economic, and market drivers of direct hydrogen PEM fuel cell adoption. The project was executed over a 6-year period (2003 to 2010) and a variety of analyses were completed in that period. The analyses presented in the final report include: Commercialization scenarios for stationary generation through 2015 (2004); Stakeholder feedback on technology status and performance status of fuel cell systems (2004); Development of manufacturing costs of stationary PEM fuel cell systems for backup power markets (2004); Identification of near-term and mid-term markets for PEM fuel cells (2006); Development of the value proposition and market opportunity of PEM fuel cells in near-term markets by assessing the lifecycle cost of PEM fuel cells as compared to conventional alternatives used in the marketplace and modeling market penetration (2006); Development of the value proposition of PEM fuel cells in government markets (2007); Development of the value proposition and opportunity for large fuel cell system application at data centers and wastewater treatment plants (2008); Update of the manufacturing costs of PEM fuel cells for backup power applications (2009).

  13. Solid electrolyte-electrode system for an electrochemical cell

    Science.gov (United States)

    Tuller, H.L.; Kramer, S.A.; Spears, M.A.

    1995-04-04

    An electrochemical device including a solid electrolyte and solid electrode composed of materials having different chemical compositions and characterized by different electrical properties but having the same crystalline phase is provided. A method for fabricating an electrochemical device having a solid electrode and solid electrolyte characterized by the same crystalline phase is also provided. 17 figures.

  14. Gas generation mechanism due to electrolyte decomposition in commercial lithium-ion cell

    Science.gov (United States)

    Kumai, Kazuma; Miyashiro, Hajime; Kobayashi, Yo; Takei, Katsuhito; Ishikawa, Rikio

    To elucidate the gas generation mechanism due to electrolyte decomposition in commercial lithium-ion cells after long cycling, we developed a device which can accurately determine the volume of generated gas in the cell. Experiments on Li xC 6/Li 1- xCoO 2 cells using electrolytes such as 1 M LiPF 6 in propylene carbonate (PC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) are presented and discussed. In the nominal voltage range (4.2-2.5 V), compositional change due mainly to ester exchange reaction occurs, and gaseous products in the cell are little. Generated gas volume and compositional change in the electrolyte are detected largely in overcharged cells, and we discussed that gas generation due to electrolyte decomposition involves different decomposition reactions in overcharged and overdischarged cells.

  15. Membrane electrolytic cell for minimizing hypochlorite and chlorate formation

    International Nuclear Information System (INIS)

    An electrolytic cell for the electrolysis of an alkali metal chloride brine is comprised of an anode compartment and a cathode compartment separated by a cation exchange membrane. The anode is comprised of an unflattened expanded structure of a valve metal selected from the group consisting of titanium, tantalum, niobium, and alloys thereof. At least one side of the anode has as the electrochemically active surface an electrodeposited layer of a valve metal oxide. A plurality of cracks traverse the electrodeposited layer and a coating of a platinum metal group oxide covers the electrodeposited layer and substantially fills the cracks. The cationic exchange membrane is comprised of a laminated structure having a first surface adapted to contact an anolyte in which the ion exchange groups are predominately sulfonic acid groups. The first surface is also in contact with the electrochemically active surface of the anode. A second surface of the cation exchange membrane, adapted to contact a catholyte, has ion exchange groups which are predominately carboxylic acid groups. The cathode positioned in the cathode compartment is spaced apart from the cation exchange membrane. The cell operates with both a low chlorine overvoltage and a low oxygen overvoltage. During electrolysis of alkali metal chloride brines, the formation of hypochlorite and chlorate ions is minimized and the alkali metal hydroxides produced have low chlorate concentrations and are suitable for use without further treatment in chlorate-sensitive applications. Spent brine treatment is simplified and at reduced costs

  16. Multiphase transport in polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Gauthier, Eric D.

    Polymer electrolyte membrane fuel cells (PEMFCs) enable efficient conversion of fuels to electricity. They have enormous potential due to the high energy density of the fuels they utilize (hydrogen or alcohols). Power density is a major limitation to wide-scale introduction of PEMFCs. Power density in hydrogen fuel cells is limited by accumulation of water in what is termed fuel cell `flooding.' Flooding may occur in either the gas diffusion layer (GDL) or within the flow channels of the bipolar plate. These components comprise the electrodes of the fuel cell and balance transport of reactants/products with electrical conductivity. This thesis explores the role of electrode materials in the fuel cell and examines the fundamental connection between material properties and multiphase transport processes. Water is generated at the cathode catalyst layer. As liquid water accumulates it will utilize the largest pores in the GDL to go from the catalyst layer to the flow channels. Water collects to large pores via lateral transport at the interface between the GDL and catalyst layer. We have shown that water may be collected in these large pores from several centimeters away, suggesting that we could engineer the GDL to control flooding with careful placement and distribution of large flow-directing pores. Once liquid water is in the flow channels it forms slugs that block gas flow. The slugs are pushed along the channel by a pressure gradient that is dependent on the material wettability. The permeable nature of the GDL also plays a major role in slug growth and allowing bypass of gas between adjacent channels. Direct methanol fuel cells (DMFCs) have analogous multiphase flow issues where carbon dioxide bubbles accumulate, `blinding' regions of the fuel cell. This problem is fundamentally similar to water management in hydrogen fuel cells but with a gas/liquid phase inversion. Gas bubbles move laterally through the porous GDL and emerge to form large bubbles within the

  17. Lithium Ion Electrolytes and Lithium Ion Cells With Good Low Temperature Performance

    Science.gov (United States)

    Smart, Marshall C. (Inventor); Bugga, Ratnakumar V. (Inventor)

    2014-01-01

    There is provided in one embodiment of the invention an electrolyte for use in a lithium ion electrochemical cell. The electrolyte comprises a mixture of an ethylene carbonate (EC), an ethyl methyl carbonate (EMC), an ester cosolvent, and a lithium salt. The ester cosolvent comprises methyl propionate (MP), ethyl propionate (EP), methyl butyrate (MB), ethyl butyrate (EB), propyl butyrate (PB), or butyl butyrate (BB). The electrochemical cell operates in a temperature range of from about -60 C to about 60 C. In another embodiment there is provided a lithium ion electrochemical cell using the electrolyte of the invention.

  18. A study of the thin film battery electrolyte lithium phosphorus oxynitride deposited by an ion beam assisted process

    Science.gov (United States)

    Vereda-Moratilla, Fernando

    Thin film Li-ion batteries are currently the subject of a world-wide research effort because of their many potential applications as portable energy sources. One of the key elements of these batteries is the electrolyte. Since it was first produced in the early 1990's, the preferred solid state thin film Li-ion electrolyte is lithium phosphorus oxynitride (LiPON), which is normally grown by means of reactive rf sputtering of a Li3PO 4 target in an N2 atmosphere. Solid electrolytes such as LiPON have several advantages compared to the liquid electrolytes normally used in bulk batteries. Solid electrolytes avoid leakage and have excellent charge-discharge cycling properties. Furthermore, sputtered-deposited LiPON proved to be stable versus Li+/Li from 0 to +5.5 V, which exceeded the stability window of any of the liquid electrolytes. In this work we present a general study of the properties of LiPON thin films deposited by an alternative process: ion beam assisted deposition (IBAD). In this process Li3PO4 is vacuum thermally evaporated and the condensing film is simultaneously bombarded with nitrogen ions which incorporate to form LiPON. Because of its application as an electrolyte and because of a previous study in which we showed that tensile stress led to cracking of the LiPON films and subsequently to shorting of the battery devices, the emphasis of the study was placed on improving the electrochemical properties of the films and on reducing their residual stress. Additional effort was aimed at learning about the structure and the composition of our films. It has been shown that IBAD LiPON thin films are undoubtedly capable of high quality performance as the electrolyte in Li-ion thin film batteries. Their ionic conductivity is almost as high, and their electronic conductivity as low, as those of the sputtered films. Their major advantages when compared to sputtered LiPON films are: (i) a higher deposition rate; (ii) a lower concentration of reduced-phosphorus in

  19. Low Cost Ferritic Stainless Steel in Dye Sensitized Solar Cells with Cobalt Complex Electrolyte

    OpenAIRE

    Miettunen, Kati; Jouttijärvi, Sami; Jiang, Roger; Saukkonen, Tapio; Romu, Jyrki; Halme, Janne; Lund, Peter

    2014-01-01

    Cheap ferritic stainless steel is applied here as the counter electrode substrate in dye sensitized solar cells with cobalt complex electrolyte. A 5.0% efficiency was reached with these type of cells which is more than 2.5 times higher compared to previously reported devices with metal counter electrode and cobalt complex electrolyte. The electrochemical impedance spectra analysis showed that the best cells with the ferritic steel counter electrode had as low charge transfer resistance (3.6 Ω...

  20. Understanding the transport processes in polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Cheah, May Jean

    Polymer electrolyte membrane (PEM) fuel cells are energy conversion devices suitable for automotive, stationary and portable applications. An engineering challenge that is hindering the widespread use of PEM fuel cells is the water management issue, where either a lack of water (resulting in membrane dehydration) or an excess accumulation of liquid water (resulting in fuel cell flooding) critically reduces the PEM fuel cell performance. The water management issue is addressed by this dissertation through the study of three transport processes occurring in PEM fuel cells. Water transport within the membrane is a combination of water diffusion down the water activity gradient and the dragging of water molecules by protons when there is a proton current, in a phenomenon termed electro-osmotic drag, EOD. The impact of water diffusion and EOD on the water flux across the membrane is reduced due to water transport resistance at the vapor/membrane interface. The redistribution of water inside the membrane by EOD causes an overall increase in the membrane resistance that regulates the current and thus EOD, thereby preventing membrane dehydration. Liquid water transport in the PEM fuel cell flow channel was examined at different gas flow regimes. At low gas Reynolds numbers, drops transitioned into slugs that are subsequently pushed out of the flow channel by the gas flow. The slug volume is dependent on the geometric shape, the surface wettability and the orientation (with respect to gravity) of the flow channel. The differential pressure required for slug motion primarily depends on the interfacial forces acting along the contact lines at the front and the back of the slug. At high gas Reynolds number, water is removed as a film or as drops depending on the flow channel surface wettability. The shape of growing drops at low and high Reynolds number can be described by a simple interfacial energy minimization model. Under flooding conditions, the fuel cell local current

  1. Hydroponics gel as a new electrolyte gelling agent for alkaline zinc-air cells

    Science.gov (United States)

    Othman, R.; Basirun, W. J.; Yahaya, A. H.; Arof, A. K.

    The viability of hydroponics gel as a new alkaline electrolyte gelling agent is investigated. Zinc-air cells are fabricated employing 12 wt.% KOH electrolyte immobilised with hydroponics gel. The cells are discharged at constant currents of 5, 50 and 100 mA. XRD and SEM analysis of the anode plates after discharge show that the failure mode is due to the formation of zinc oxide insulating layers and not due to any side reactions between the gel and the plate or the electrolyte.

  2. 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.

  3. Performance enhancement of phosphoric acid fuel cell using phosphosilicate gel based electrolyte

    Institute of Scientific and Technical Information of China (English)

    Kajari Kargupta; Swati Saha; Dipali Banerjee; Mrinal Seal; Saibal Ganguly

    2012-01-01

    Replacement of phosphoric acid electrolyte by phosphosilicate gel based electrolytes is proposed for performance enhancement of phosphoric acid fuel cell (PAFG).Phosphosilicate gel in paste form and in powder form is synthesized from tetraethoxysilane and orthophosphoric acid using sol-gel method for two different P/Si ratio of 5 and 1.5 respectively.Replacement of phosphoric acid electrolyte by phosphosilicate gel paste enhances the peak power generation of the fuel cell by 133% at 120 ℃ cell temperature; increases the voltage generation in the ohmic regime and extends the maximum possible load current.Polyinyl alcohol (PVA) is used to bind the phosphosilicate gel powder and to form the hybrid crosslinked gel polymer electrolyte membrane.Soaking the membrane with phosphoric acid solution,instead of that with water improves the proton conductivity of the membrane,enhances the voltage and power generation by the fuel cell and extends the maximum possible operating temperature.At lower operating temperature of 70 ℃,peak power produced by phosphosilicate gel polymer electrolyte membrane fuel cell ( PGMFC ) is increased by 40% compared to that generated by phosphoric acid fuel cell ( PAFC ).However,the performance of composite membrane diminishes as the cell temperature increases.Thus phosphosilicate gel in paste form is found to be a good alternative of phosphoric acid electrolyte at medium operating temperature range while phosphosilicate gel-PVA composite offers performance enhancement at low operating temperatures.

  4. Fabrication of Pt deposited on carbon nanotubes and performance of its polymer electrolyte membrane fuel cells

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A new method of depositing nano-sized Pt particles on the surface of the carbon nano-tubes was introduced, and the performance of Pt/carbon nanotube compound on polymer electrolyte membrane fuel cells was measured. The experimental results show that the fine platinum particles (about 3 nm) were well dispersed on carbon nanotubes, which demonstrates the excellent catalytic properties of the Pt/CNTs compound in polymer electrolyte membrane fuel cells.

  5. Nafion and modified-Nafion membranes for polymer electrolyte fuel cells: An overview

    Indian Academy of Sciences (India)

    A K Sahu; S Pitchumani; P Sridhar; A K Shukla

    2009-06-01

    Polymer electrolyte fuel cells (PEFCs) employ membrane electrolytes for proton transport during the cell reaction. The membrane forms a key component of the PEFC and its performance is controlled by several physical parameters, viz. water up-take, ion-exchange capacity, proton conductivity and humidity. The article presents an overview on Nafion membranes highlighting their merits and demerits with efforts on modified-Nafion membranes.

  6. Fermi Potential across Working Solid Oxide Cells with Zirconia or Ceria Electrolytes

    DEFF Research Database (Denmark)

    Jacobsen, Torben; Chatzichristodoulou, Christodoulos; Mogensen, Mogens Bjerg

    2014-01-01

    Two kinds of electrochemical relevant potentials are important in order to describe several observed phenomena in operating electrochemical cells with solid electrolytes. This paper gives illustrative examples of how the profiles of the two potential types, the Galvani potential, φ, and the elect...... stabilized zirconia (YSZ) electrolytes. The nature of the two potential types and the importance of each of them for the cell operation are explained....

  7. Thermal stability of alkyl carbonate mixed-solvent electrolytes for lithium ion cells

    Science.gov (United States)

    Kawamura, Tetsuya; Kimura, Arihisa; Egashira, Minato; Okada, Shigeto; Yamaki, Jun-Ichi

    The thermal stability of some mixed-solvent electrolytes used in lithium cells was measured by differential scanning calorimetry (DSC) using airtight containers. The electrolytes used were ethylene carbonate ( EC)+ diethyl carbonate ( DEC) , EC+ dimethyl carbonate ( DMC) , propylene carbonate (PC)+DEC, and PC+DMC in which was dissolved 1 M LiPF 6 or 1 M LiClO 4. The influence of water addition and lithium metal addition on the thermal behavior of these electrolytes was also investigated. The exothermic peak of LiPF 6 electrolytes containing DEC was found at 255 °C, and the peak temperature of the electrolytes containing DEC was 15-20 °C lower than that of LiPF 6 electrolytes containing DMC. This effect was also observed in the electrolytes including LiClO 4. DMC was found to be more reactive than DEC. The thermal behavior of various kinds of LiPF 6 electrolytes with lithium metal was measured by DSC. The exothermic reaction of 1 M LiPF 6/EC+DEC, 1 M LiPF 6/EC+DMC, and 1 M LiPF 6/PC+DMC with lithium metal began at the melting point of lithium metal because of the break down of the solid electrolyte interface (SEI). The temperature was approximately 180 °C, whereas the self-heating of 1 M LiPF 6/PC+DEC occurred before the melting point of lithium metal. The temperature at which the self-exothermal reaction began was 140 °C. Therefore, the lithium metal in this electrolyte was found to be thermally unstable. When water was added to the above electrolytes with lithium metal, the exothermic reaction began at less than 130 °C, probably due to a collapse of SEI in response to the HF that was a product of the reaction between LiPF 6 and the added water.

  8. X-ray evaluation of the boundary between polymer electrolyte and platinum and carbon functionalization to conduct protons in polymer electrolyte fuel cells

    Science.gov (United States)

    Oka, Kazuki; Ogura, Yuta; Izumi, Yasuo

    2014-07-01

    In polymer electrolyte fuel cells (PEFCs), it is important to secure proximate diffusion paths of reactants and electrons. One approach is to optimize the boundary between polymer electrolyte and Pt nanoparticle surface. Based on synchrotron X-ray absorption fine structure to monitor directly the status of catalysts in PEFCs, it was found that Pt sites were reduced to Pt0 by alcohols contained in polymer electrolyte dispersion solution during the preparation of cathode of PEFC. As in membrane electrolyte assembly, only the Pt sites not covered by polymer electrolyte re-oxidized to Pt2+/4+. Thus, the interface between Pt and polymer electrolyte was evaluated. The other approach is to functionalize carbon surface with sulfonate/sulfate group to conduct protons. Similar level of proton conductivity was observed in current-voltage dependence compared to using polymer electrolyte, but polymer electrolyte was advantageous to lose less voltage for activation. Based on this comparison, optimum catalyst on cathode is proposed comprising surface sulfonate/sulfate group on carbon mixed with polymer electrolyte. Further optimization of cathode catalyst is proposed to functionalize carbon with sulfonate group linked to fluorocarbon branch.

  9. Enhancing the performance of dye-sensitized solar cells by incorporating nanosilicate platelets in gel electrolyte

    KAUST Repository

    Lai, Yi-Hsuan

    2009-10-01

    Two kinds of gel-type dye-sensitized solar cells (DSSCs), composed of two types of electrolytes, were constructed and the respective cell performance was evaluated in this study. One electrolyte, TEOS-Triton X-100 gel, was based on a hybrid organic/inorganic gel electrolyte made by the sol-gel method and the other was based on poly(vinyidene fluoride-co-hexafluoro propylene) (PVDF-HFP) copolymer. TEOS-Triton X-100 gel was based on the reticulate structure of silica, formed by hydrolysis, and condensation of tetraethoxysilane (TEOS), while its organic subphase was a mixture of surfactant (Triton X-100) and ionic liquid electrolytes. Both DSSC gel-type electrolytes were composed of iodine, 1-propy-3-methyl-imidazolium iodide, and 3-methoxypropionitrile to create the redox couple of I3 -/I-. Based on the results obtained from the I-V characteristics, it was found that the optimal iodine concentrations for the TEOS-Triton X-100 gel electrolyte and PVDF-HFP gel electrolyte are 0.05 M and 0.1 M, respectively. Although the increase in the iodine concentration could enhance the short-circuit current density (JSC), a further increase in the iodine concentration would reduce the JSC due to increased dark current. Therefore, the concentration of I2 is a significant factor in determining the performance of DSSCs. In order to enhance cell performance, the addition of nanosilicate platelets (NSPs) in the above-mentioned gel electrolytes was investigated. By incorporating NSP-Triton X-100 into the electrolytes, the JSC of the cells increased due to the decrease of diffusion resistance, while the open circuit voltage (VOC) remained almost the same. As the loading of the NSP-Triton X-100 in the TEOS-Triton X-100 gel electrolyte increased to 0.5 wt%, the JSC and the conversion efficiency increased from 8.5 to 12 mA/cm2 and from 3.6% to 4.7%, respectively. However, the JSC decreased as the loading of NSP-Triton X-100 exceeded 0.5 wt%. At higher NSP-Triton X-100 loading, NSPs acted as

  10. Fermi Potential across Working Solid Oxide Cells with Zirconia or Ceria Electrolytes

    DEFF Research Database (Denmark)

    Jacobsen, Torben; Chatzichristodoulou, Christodoulos; Mogensen, Mogens Bjerg

    2014-01-01

    A solid electrolyte will always possess a finite electronic conductivity, in particular electrolytes like doped ceria that easily get reduced and become mixed ionic and electronic conductors. This given rise too high leak currents through the solid oxide cell (SOC). Especially, problems have been...... observed for ceria based electrolytes, but also in case of solid oxide electrolyser cells (SOEC) with yttria stabilized zirconia (YSZ) big electronic leak currents have been observed for very high overvoltages on one or both electrodes. Furthermore, it is important to realize that the potential gradient...... various temperatures and operation conditions. Furthermore, the situation within cells based on gadolinia doped ceria (CGO) and on YSZ electrolytes are compared. Finally, it is discussed how the Fermi potential and electron conductivity will be affected by the various parameters including operation...

  11. 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.

  12. Comparing Electrolytes in Prestorage Leukocyte-Reduced Packed Cell versus Unfiltered Packed Cell

    OpenAIRE

    Fallahi, L; Ghiliyan, R; Hashemi, A; A. Fatemi; M. Saeedi

    2013-01-01

    Background Blood transfusion is associated with side effects caused by residual leukocytes in blood and blood components. Using leukodepleted blood components can decrease some of these adverse effects. Among the various methods to remove leukocytes in blood components, prestorage leukoreduction has been most efficient, but the evidence of clinical side effects awaits further studies. We evaluated changes of electrolytes in prestorage leukocyte-reduced red blood cells. Materials and Methods I...

  13. Characteristics of Subfreezing Operation of Polymer Electrolyte Membrane Fuel Cells

    Science.gov (United States)

    Mishler, Jeffrey Harris

    Polymer Electrolyte Membrane (PEM) Fuel Cells are capable of high efficiency operation, and are free of NOx, SOx, and CO2 emissions when using hydrogen fuel, and ideally suited for use in transportation applications due to their high power density and low operating temperatures. However, under subfreezing conditions which may be encountered during winter seasons in some areas, product water will freeze within the membrane, cathode side catalyst layer and gas diffusion media, leading to voltage loss and operation failure. Experiments were undertaken in order to characterize the amount and location of water during fuel cell operation. First, in-situ neutron radiography was undertaken on the fuel cells at a normal operating temperature for various operating current densities, inlet relative humidities, and diffusion media hydrophobicities. It was found that more hydrophobic cathode microporous layer (MPL) or hydrophilic anode MPL may result in a larger amount of water transporting back to the anode. The water profiles along the channels were measured and the point of liquid water emergence, where two phase flow begins, was compared to previous models. Secondly, under subfreezing temperatures, neutron imaging showed that water ice product accumulates because of lack of a water removal mechanism. Water was observed under both the lands and channels, and increased almost linearly with time. It is found that most ice exists in the cathode side. With evidence from experimental observation, a cold start model was developed and explained, following existing approaches in the literature. Three stages of cold start are explained: membrane saturation, ice storage in catalyst layer pores, and then ice melting. The voltage losses due to temperature change, increased transport resistance, and reduced electrochemical surface area. The ionic conductivity of the membrane at subfreezing temperatures was modeled. Voltage evolution over time for isothermal cold starts was predicted and

  14. Dye-sensitized solar cells with ionic gel electrolytes prepared from imidazolium salts and agarose

    International Nuclear Information System (INIS)

    New ionic gel electrolytes, semi-solid state electrolytes comprised of ionic liquid and gelator were investigated in order to improve the durability of dye-sensitized solar cells (DSCs). The ionic gels were prepared from agarose, natural polysaccharide, and 1-alkyl-3-methyl-imidazolium salts. The gels showed sufficient mechanical strength even though a very small amount of agarose was added (1.0-1.5 wt%). The photon to electron conversion efficiency of the DSCs containing ionic gel electrolyte was 2.93% under simulated sunlight (air mass 1.5) with a light intensity of 100 mW cm-2. (authors)

  15. Highly efficient dye-sensitized solar cells using a composite electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Bofei, Xue; Hongxia, Wang; Yongsheng, Hu; Hong, Li; Zaoxiang, Wang; Qingbo, Meng; Xuejie, Huang; Liquan, Chen [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing (China); Osamu, Sato; Akira, Fujishima [Research Laboratory for Optical Science, Kanagawa Academy of Science and Technology, Sakado Kawasaki (Japan)

    2006-05-15

    A dye-sensitized solar cell with efficiency over 4% has been fabricated using a composite electrolyte containing LiI(CH{sub 3}OH){sub 4}-I{sub 2}, SiO{sub 2} particles and an ionic liquid, triethylamine hydro-thiocyanate (THT). The ionic liquid is used as a cooperative electrolyte. Nano-sized SiO{sub 2} particles act as both an inhibitor of crystal growth of the solid-state electrolyte and an insulator layer between the photo-anode and the counter electrode. (authors)

  16. 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)

  17. Electrolyte Suitable for Use in a Lithium Ion Cell or Battery

    Science.gov (United States)

    McDonald, Robert C. (Inventor)

    2014-01-01

    Electrolyte suitable for use in a lithium ion cell or battery. According to one embodiment, the electrolyte includes a fluorinated lithium ion salt and a solvent system that solvates lithium ions and that yields a high dielectric constant, a low viscosity and a high flashpoint. In one embodiment, the solvent system includes a mixture of an aprotic lithium ion solvating solvent and an aprotic fluorinated solvent.

  18. Dye-sensitized solar cells and solar module using polymer electrolytes: Stability and performance investigations

    OpenAIRE

    Jilian Nei de Freitas; Viviane Carvalho Nogueira; Bruno Ieiri Ito; Mauro Alfredo Soto-Oviedo; Claudia Longo; Marco-Aurelio De Paoli; Ana Flávia Nogueira

    2006-01-01

    We present recent results on solid-state dye-sensitized solar cell research using a polymer electrolyte based on a poly(ethylene oxide) derivative. The stability and performance of the devices have been improved by a modification in the method of assembly of the cells and by the addition of plasticizers in the electrolyte. After 30 days of solar irradiation (100 mW cm-2) no changes in the cell's efficiency were observed using this new method. The effect of the active area size on cell perform...

  19. Rechargeable Zn-air batteries: Progress in electrolyte development and cell configuration advancement

    Science.gov (United States)

    Xu, M.; Ivey, D. G.; Xie, Z.; Qu, W.

    2015-06-01

    Zn-air batteries, which are cost-effective and have high energy density, are promising energy storage devices for renewable energy and power sources for electric transportation. Nevertheless, limited charge and discharge cycles and low round-trip efficiency have long been barriers preventing the large-scale deployment of Zn-air batteries in the marketplace. Technology advancements for each battery component and the whole battery/cell assembly are being pursued, with some key milestones reached during the past 20 years. As an example, commercial Zn-air battery products with long lifetimes and high energy efficiencies are being considered for grid-scale energy storage and for automotive markets. In this review, we present our perspectives on improvements in Zn-air battery technology through the exploration and utilization of different electrolyte systems. Recent studies ranging from aqueous electrolytes to nonaqueous electrolytes, including solid polymer electrolytes and ionic liquids, as well as hybrid electrolyte systems adopted in Zn-air batteries have been evaluated. Understanding the benefits and drawbacks of each electrolyte, as well as the fundamental electrochemistry of Zn and air electrodes in different electrolytes, are the focus of this paper. Further consideration is given to detailed Zn-air battery configurations that have been studied and applied in commercial or nearing commercial products, with the purpose of exposing state-of-the-art technology innovations and providing insights into future advancements.

  20. 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

  1. Engineered interfaces and nano-scale thin films for solid oxide fuel cell electrolytes

    Science.gov (United States)

    Nandasiri, Manjula I.

    Solid state electrolytes with high oxygen ionic conductivity at low temperatures are required to develop cost effective and efficient solid oxide fuel cells. This study investigates the influence of engineered interfaces on the oxygen ionic conductivity of nano-scale multilayer thin film electrolytes. The epitaxial Sm2O3 doped CeO2 (SDC) and Sc2O3 stabilized ZrO2 (ScSZ) are selected as the alternative layers for the proposed multilayer thin film electrolyte based on the optimum structural, chemical, and electrical properties reported in the previous studies. The epitaxial SDC(111)/ScSZ(111) multilayer thin films are grown on high purity Al2O3(0001) substrates by oxygen-plasma assisted molecular beam epitaxy. Prior to the deposition of multilayers, the growth parameters are optimized for epitaxial CeO 2, ZrO2, SDC, and ScSZ thin films. The epitaxial orientation and surface morphology of CeO2 thin films shows dependency on the growth rate. Epitaxial CeO2(111) is obtained at relatively high growth rates (>9 A/min) at a substrate temperature of 650°C and an oxygen partial pressure of 2 x 10 -5 Torr. The same growth parameters are used for the deposition of ZrO2 thin films. ZrO2 exhibits both monoclinic and cubic phases, which is stabilized in the cubic structure by doping with Sc 2O3. The Sm and Sc evaporation rates are varied during the growth to obtain thin films of 15 mol % SmO1.5 doped CeO2 and 20 mol % ScO1.5 stabilized ZrO2, respectively. The SDC/ScSZ multilayer thin films are grown using the same growth parameters by varying the number of layers. The SDC/ScSZ multilayer thin films show significant enhancement in the oxygen ionic conductivity in comparison to single layer SDC and ScSZ thin films. The increase in the oxygen ionic conductivity with the increase in number of layers can be attributed to lattice mismatch induced ionic conductivity along the interfaces. The 8-layer film exhibits the maximum oxygen ionic conductivity with one order of magnitude

  2. Current-Distribution Measurement in Polymer Electrolyte Water Electrolysis Equipment and Polymer Electrolyte Fuel Cell Using NMR Sensor

    Science.gov (United States)

    Yokouchi, Yasuo; Ogawa, Kuniyasu; Haishi, Tomoyuki; Ito, Kohei

    In a polymer electrolyte fuel cell (PEFC), the current density through the polymer electrolyte membrane (PEM) is distributed along the electrode on the membrane electrode assembly (MEA). To increase the electric power density of a PEFC, it is necessary to locate local decreases in current density where electric power generation decreases due to a lack of hydrogen, flooding, and so on. Therefore, achieving a higher current density in a PEFC requires monitoring the local current density. We developed a new method to estimate the spatial distribution of current flowing through the MEA in a polymer electrolyte water electrolysis equipment (PEWEE) and a PEFC using Nuclear-Magnetic-Resonance (NMR) sensors. The magnetic field strength induced by current through the MEA in a PEWEE is acquired as the frequency shift of the NMR signal which is measured by the NMR sensor. The spatial distributions of the frequency shifts occurring along the MEA in a PEWEE and a PEFC was measured. In order to verify the method, the magnetic field strength induced by the current through the gas diffusion layer (GDL) in a PEWEE was analyzed theoretically under the assumption that the current through MEA was uniform. The frequency shift was then calculated as a function of the geometry of the GDL, current, and the position of the NMR sensor. From experimental and theoretical results, the frequency shift of the NMR signal is proportional to current density and depends on the position of the sensors. Using the measurement system, we also obtained the current distribution through the GDL in a PEFC generating electric power. In these studies, the experimental and theoretical results agree.

  3. Effect of polymer electrolyte on the performance of natural dye sensitized solar cells

    Science.gov (United States)

    Adel, R.; Abdallah, T.; Moustafa, Y. M.; Al-sabagh, A. M.; Talaat, H.

    2015-10-01

    Polymer electrolyte based on polyacrylonitrile (PAN), Ethylene Carbonate (EC) and Acetonitrile (ACN) mixed with Potassium Iodide and Iodine in liquid and thin film forms were employed in natural dye sensitized solar cells (NDSSCs). Three natural dyes; black berry, hibiscus and rose are used as the sensitizing dye. The NDSSCs used, follow the configuration: FTO/TiO2/Natural Dye/Electrolyte/ Carbon/FTO. The liquid form polymer electrolyte with black berry natural dye gives an increase of 111% in short circuit photocurrent density (Jsc), 17.5% to open circuit voltage (Voc), fill factor of 0.57 ± 0.05 and three times increase in the conversion efficiency of 0.242 ± 0.012% compared to the iodine electrolyte.

  4. Optimizing end-group cross-linking polymer electrolytes for fuel cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yu Seung [Los Alamos National Laboratory; Lee, Kwan Soo [Los Alamos National Laboratory; Jeong, Myung - Hwan [GIST, KOREA; Lee, Jae - Suk [GIST, KOREA

    2009-01-01

    This paper demonstrates the optimization of proton conductivity and water uptake for cross-linkable polymer electrolytes through synthesis and characterization of end-group cross-linkable sulfonated poly(arylene ether) copolymers (ESF-BPs). The extent of reaction of cross-linking was controlled by reaction time resulting in a series of polymers with two, independent tunable parameters, degree of sulfonation (DS) and degree of cross-linking (DC). For the polymers presented, cross-linking improved proton conductivity while reducing water uptake, an uncommon trend in polymer electrolytes where water is critical for proton conduction. Other trends relating to changes are reported and the results yield insight into the role of DS and DC and how to optimize electrochemical properties and performance of polymer electrolytes through these tunable parameters. Select polymer electrolytes were tested in fuel cells where performance and durability with accelerated relative humidity cycling were compared with Nafion{reg_sign}.

  5. A High Efficiency Chlorophyll Sensitized Solar Cell with Quasi Solid PVA Based Electrolyte

    Directory of Open Access Journals (Sweden)

    H. C. Hassan

    2016-01-01

    Full Text Available The objective of this work is to investigate the performance of chlorophyll sensitized solar cells (CSSCs with gel electrolyte based on polyvinyl alcohol (PVA with single iodide salt (potassium iodide (KI and double salt (KI and tetrapropylammonium iodide (TPAI. Chlorophyll was extracted from the bryophyte Hyophila involuta. The CSSC with electrolyte containing only KI salt produced a short circuit current density (Jsc of 4.59 mA cm−2, open circuit voltage (Voc of 0.61 V, fill factor (FF of 0.64, and efficiency (η of 1.77%. However, the CSSC with double salt electrolyte exhibited Jsc of 5.96 mA cm−2, Voc of 0.58 V, fill factor FF of 0.58, and η of 2.00%. Since CSSC with double salt electrolyte showed better efficiency, other cells fabricated will use the double salt electrolyte. On addition of 0.7 M tetrabutyl pyridine (TBP to the double salt electrolyte, the cell’s efficiency increased to 2.17%, Jsc=5.37 mA cm−2, Voc=0.55 V, and FF = 0.73. With 5 mM chenodeoxycholic acid (CDCA added to the chlorophyll, the light to electricity efficiency increased to 2.62% with Jsc of 8.44 mA cm−2, Voc of 0.54 V, and FF of 0.58.

  6. Numerical Calculations of Single-Cell Electroporation with an Electrolyte-Filled Capillary

    OpenAIRE

    Zudans, Imants; Agarwal, Aparna; Orwar, Owe; Weber, Stephen G.

    2007-01-01

    An electric field is focused on one cell in single-cell electroporation. This enables selective electroporation treatment of the targeted cell without affecting its neighbors. While factors that lead to membrane permeation are the same as in bulk electroporation, quantitative description of the single-cell experiments is more complicated. This is due to the fact that the potential distribution cannot be solved analytically. We present single-cell electroporation with an electrolyte-filled cap...

  7. Dextran based highly conductive hydrogel polysulfide electrolyte for efficient quasi-solid-state quantum dot-sensitized solar cells

    International Nuclear Information System (INIS)

    Highlights: ► Dextran based hydrogel is first used to prepare quasi-solid-state polysulfide electrolyte for quantum dot-sensitized solar cells. ► The ion conductivity of hydrogel electrolyte shows almost the same value as the liquid electrolyte. ► The liquid state at elevated temperature of hydrogel electrolyte allows for a good contact between electrolyte and CdS/CdSe co-sensitized TiO2 photoanode. ► The hydrogel electrolyte based cell exhibits slightly lower power conversion efficiency than that of liquid electrolyte based cell. ► The dynamic electron transfer mechanism in hydrogel electrolyte based cell is examined in detail by EIS and CIMPS/IMVS. -- Abstract: Highly conductive hydrogel polysulfide electrolyte is first fabricated using dextran as gelator and used as quasi-solid-state electrolyte for quantum dot-sensitized solar cells (QDSSCs). The hydrogel electrolyte with gelator concentration of 15 wt% shows almost the same conductivity as the liquid one. Moreover, its liquid state at elevated temperature allow for the well penetration into the pores in electrodeposited CdS/CdSe co-sensitized TiO2 photoanode. This gel electrolyte based QDSSC exhibits power conversion efficiency (η) of 3.23% under AG 1.5 G one sun (100 mW cm−2) illumination, slightly lower than that of liquid electrolyte based cell (3.69%). The dynamic electron transfer mechanism of the gel and liquid electrolyte based QDSSC are examined by electrochemical impedance spectroscopy (EIS) and controlled intensity modulated photocurrent/photovoltage spectroscopy (CIMPS/IMVS). It is found that the electron transport in gel electrolyte based cell is much faster than the liquid electrolyte based cell but it tends to recombine more easily than the latter. However, these differences fade away with increasing the light intensity, showing declining electron collection efficiency at higher light intensity illumination. As a result, a conversion efficiency of 4.58% is obtained for the gel

  8. Numerical investigations on two-phase flow in polymer electrolyte fuel cells

    NARCIS (Netherlands)

    Qin, C.Z.

    2012-01-01

    Numerical modeling plays an important role in understanding various transport processes in polymer electrolyte fuel cells (PEFCs). It can not only provide insights into the development of new PEFC architectures, but also optimize operating conditions for better cell performance. Water balance is cri

  9. Estimating Of Etchant Copper Concentration In The Electrolytic Cell Using Artificial Neural Networks

    Directory of Open Access Journals (Sweden)

    Muzher M. Ibrahem

    2013-05-01

    Full Text Available      In  this paper, Artificial Neural Networks (ANN, which are known for their ability to model nonlinear systems, provide accurate approximations of system behavior and are typically much more computationally efficient than phenomenological models  are used to predict the etchant copper concentration in the electrolytic cell in terms of electric potential, operating time, temperature of the electrolytic cell , ratio of surface area of poles per unit volume of solution  and the distance between poles. In this paper 350 sets of data are used to trained and test the network.. The best results were achieved using a model based on a feedforword Artificial Neural Network (ANN with one hidden layer and fifteen neurons in the hidden layer gives a very close prediction of the copper concentration in the electrolytic cell.

  10. Three-dimensional ionic conduction in the strained electrolytes of solid oxide fuel cells

    Science.gov (United States)

    Han, Yupei; Zou, Minda; Lv, Weiqiang; Mao, Yiwu; Wang, Wei; He, Weidong

    2016-05-01

    Flexible power sources including fuel cells and batteries are the key to realizing flexible electronic devices with pronounced foldability. To understand the bending effects in these devices, theoretical analysis on three-dimensional (3-D) lattice bending is necessary. In this report, we derive a 3-D analytical model to analyze the effects of electrolyte crystal bending on ionic conductivity in flexible solid-state batteries/fuel cells. By employing solid oxide fuel cells as a materials' platform, the intrinsic parameters of bent electrolyte materials, including lattice constant, Young's modulus, and Poisson ratio, are evaluated. Our work facilitates the rational design of highly efficient flexible electrolytes for high-performance flexible device applications.

  11. Increased Water Retention in Polymer Electrolyte Membranes at Elevated Temperatures Assisted by Capillary Condensation

    International Nuclear Information System (INIS)

    We establish a new systematic methodology for controlling the water retention of polymer electrolyte membranes. Block copolymer membranes comprising hydrophilic phases with widths ranging from 2 to 5 nm become wetter as the temperature of the surrounding air is increased at constant relative humidity. The widths of the moist hydrophilic phases were measured by cryogenic electron microscopy experiments performed on humid membranes. Simple calculations suggest that capillary condensation is important at these length scales. The correlation between moisture content and proton conductivity of the membranes is demonstrated.

  12. Increased Water Retention in Polymer Electrolyte Membranes at Elevated Temperatures Assisted by Capillary Condensation

    Energy Technology Data Exchange (ETDEWEB)

    Park, M.J.; Downing, K.H.; Jackson, A.; Gomez, E.D.; Minor, A.M.; Cookson, D.; Weber, A.Z.; Balsara, N.P. (UCB); (NIST); (LBNL); (UC)

    2008-10-03

    We establish a new systematic methodology for controlling the water retention of polymer electrolyte membranes. Block copolymer membranes comprising hydrophilic phases with widths ranging from 2 to 5 nm become wetter as the temperature of the surrounding air is increased at constant relative humidity. The widths of the moist hydrophilic phases were measured by cryogenic electron microscopy experiments performed on humid membranes. Simple calculations suggest that capillary condensation is important at these length scales. The correlation between moisture content and proton conductivity of the membranes is demonstrated.

  13. Present status of solid state photoelectrochemical solar cells and dye sensitized solar cells using PEO-based polymer electrolytes

    International Nuclear Information System (INIS)

    Due to energy crises in the future, much effort is being directed towards alternate sources. Solar energy is accepted as a novel substitute for conventional sources of energy. Out of the long list of various types of solar cells available on the market, solid state photoelectrochemical solar cells (SSPECs) and dye sensitized solar cells (DSSCs) are proposed as an alternative to costly crystalline solar cell. This review provides a common platform for SSPECs and DSSCs using polymer electrolyte, particularly on polyethylene oxide (PEO)-based polymer electrolytes. Due to numerous advantageous properties of PEO, it is frequently used as an electrolyte in both SSPECs as well as DSSCs. In DSSCs, so far high efficiency (more than 11%) has been obtained only by using volatile liquid electrolyte, which suffers many disadvantages, such as corrosion, leakage and evaporation. The PEO-based solid polymer proves its importance and could be used to solve the problems stated above. The recent developments in SSPECs and DSSCs using modified PEO electrolytes by adding nano size inorganic fillers, blending with low molecular weight polymers and ionic liquid (IL) are discussed in detail. The role of ionic liquid in modifying the electrical, structural and photoelectrochemical properties of PEO polymer electrolytes is also described. (review)

  14. Low-EC-Content Electrolytes for Low-Temperature Li-Ion Cells

    Science.gov (United States)

    Smart, Marshall; Bugga, Ratnakumar; Surampudi, Subbarao

    2003-01-01

    Electrolytes comprising LiPF6 dissolved at a concentration of 1.0 M in three different mixtures of alkyl carbonates have been found well suited for use in rechargeable lithium-ion electrochemical cells at low temperatures. These and other electrolytes have been investigated in continuing research directed toward extending the lower limit of practical operating temperatures of Li-ion cells down to -60 C. This research at earlier stages was reported in numerous previous NASA Tech Briefs articles, the three most recent being "Ethyl Methyl Carbonate as a Cosolvent for Lithium-Ion Cells" (NPO-20605), Vol. 25, Low-EC-Content Electrolytes for Low-Temperature Li-Ion Cells No. 6 (June 2001), page 53; "Alkyl Pyrocarbonate Electrolyte Additives for Li-Ion Cells" (NPO-20775), Vol. 26, No. 5 (May 2002), page 37; and "Fluorinated Alkyl Carbonates as Cosolvents in Li-Ion Cells (NPO-21076), Vol. 26, No. 5 (May 2002), page 38. The present solvent mixtures, in terms of volume proportions of their ingredients, are 1 ethylene carbonate (EC) + 1 diethyl carbonate (DEC) + 1 dimethyl carbonate (DMC) + 3 ethyl methyl carbonate (EMC); 3EC + 3DMC + 14EMC; and 1EC + 1DEC + 1DMC + 4EMC. Relative to similar mixtures reported previously, the present mixtures, which contain smaller proportions of EC, have been found to afford better performance in experimental Li-ion cells at temperatures < -20 C.

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

    Science.gov (United States)

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

    2014-04-01

    Application of anode-supported solid oxide fuel cell (SOFC) with ceria based electrolyte has often been limited by high cost of electrolyte film fabrication and high electrode polarization. In this study, dense Gd0.1Ce0.9O2 (GDC) thin film electrolytes have been fabricated on hierarchically oriented macroporous NiO-GDC anodes by a combination of freeze-drying tape-casting of the NiO-GDC anode, drop-coating GDC slurry on NiO-GDC anode, and co-firing the electrolyte/anode bilayers. Using 3D X-ray microscopy and subsequent analysis, it has been determined that the NiO-GDC anode substrates have a porosity of around 42% and channel size from around 10 μm at the electrolyte side to around 20 μm at the other side of the NiO-GDC (away from the electrolyte), indicating a hierarchically oriented macroporous NiO-GDC microstructure. Such NiO-GDC microstructure shows a tortuosity factor of ∼1.3 along the thickness direction, expecting to facilitate gas diffusion in the anode during fuel cell operation. SOFCs with such Ni-GDC anode, GDC film (30 μm) electrolyte, and La0.6Sr0.4Co0.2Fe0.8O3-GDC (LSCF-GDC) cathode show significantly enhanced cell power output of 1.021 W cm(-2) at 600 °C using H2 as fuel and ambient air as oxidant. Electrochemical Impedance Spectroscopy (EIS) analysis indicates a decrease in both activation and concentration polarizations. This study has demonstrated that freeze-drying tape-casting is a very promising approach to fabricate hierarchically oriented porous substrate for SOFC and other applications. PMID:24621230

  16. 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

  17. Effects of surfactants on agarose-based magnetic polymer electrolyte for dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Highlights: ► A novel agarose magnetic polymer electrolyte for DSSC was investigated. ► Four surfactants were introduced to improve the dispersivity of Fe3O4 nanoparticle. ► Fe3O4 nanoparticles are well dispersed and the ionic conductivity was improved. ► TW-80 was selected as the proper surfactant for magnetic polymer electrolyte. -- Abstract: Four surfactants, sodium dodecyl sulfate (SDS), polyvinylpyrrolidone (PVP), polyethylene glycol (PEG200) and polysorbate 80 (TW-80), were added to disperse Fe3O4 nanoparticles in agarose based magnetic polymer electrolyte, for the purpose of improving the performance of dye-sensitized solar cell (DSSC). Fourier transform infrared spectroscopy (FTIR) was employed to characterize the interactions between surfactants and magnetic polymer electrolyte. TW-80 and PEG200 showed good dispersion properties according to surface morphology tests. Through electrochemical impedance spectroscopy (EIS) study, the ionic conductivity, charge transfer resistance, charge recombination resistance and electron lifetime of polymer electrolytes were all improved by modification, while TW-80 modified electrolyte reached the highest ionic conductivity of 2.98 × 10−3 S/cm. Moreover, the photoelectric properties were also significantly enhanced and the best energy conversion efficiency achieved 1.83% with TW-80 modification

  18. Oxidative degradation of polybenzimidazole membranes as electrolytes for high temperature proton exchange membrane fuel cells

    DEFF Research Database (Denmark)

    Liao, J.H.; Li, Qingfeng; Rudbeck, H.C.;

    2011-01-01

    Polybenzimidazole membranes imbibed with acid are emerging as a suitable electrolyte material for high-temperature polymer electrolyte fuel cells. The oxidative stability of polybenzimidazole has been identified as an important issue for the long-term durability of such cells. In this paper the...... oxidative degradation of the polymer membrane was studied under the Fenton test conditions by the weight loss, intrinsic viscosity, size exclusion chromatography, scanning electron microscopy and Fourier transform infrared spectroscopy. During the Fenton test, significant weight losses depending on the...

  19. New operational modes for the Ta2O5-based electrolyte conductance cell

    OpenAIRE

    Olthuis, W.; Smith, A.; Zalm, van der, GM Geert; Bergveld, P.

    1994-01-01

    Based on the recently presented conductance cell, two specific operational modes are proposed. In the oscillator mode, the conductivity of the electrolyte determines the frequency of an oscillator, experimentally obtaining a shift from 10 to 27 kHz for a KCl concentration range from 0.5 to 100 mM. In the pole mode, an inductor is placed in series with the cell, giving the real electrolyte resistance at the resonance frequency of the circuit, resulting in a linear relation between the log of t...

  20. Silicon microhole arrays architecture for stable and efficient photoelectrochemical cells using ionic liquids electrolytes

    Science.gov (United States)

    Shen, Xiaojuan; Chen, Ling; Li, Junnan; Zhao, Jie

    2016-06-01

    Silicon microhole arrays (SiMHs) structure is constructed and fabricated by a low-cost maskless anodic etching process, which is applied as the photoanode for the silicon photoelectrochemical (PEC) cells. The depths of silicon microhole arrays can be independently controlled by the etching time. The light-scattering properties are also investigated. Additionally, surface morphology analysis show that large hole diameters of SiMHs is very favourable for the full-filling of ionic liquids electrolyte. Therefore, better electrochemical contact as well as high ionic conductivity of the ionic liquids electrolyte renders the PEC SiMHs solar cells to exhibit more excellent performance. After optimization, the maximum PCE could be achieved at 4.04% for the SiMHs cell. The performance of the SiMHs cell is highly comparable to that of silicon nanowires cell. More importantly, the liquid-state electrolyte is confined in the unique microhole structure, which can obviously prevent the leakage of the ionic liquids electrolyte, resulting in much better long-term stability than the reference devices. These preliminary results validate the concept of interpenetrating networks with semiconductor structure/ILs junction to develop stable and efficient PEC cells.

  1. A chemically stable electrolyte with a novel sandwiched structure for proton-conducting solid oxide fuel cells (SOFCs)

    KAUST Repository

    Bi, Lei

    2013-11-01

    A chemically stable electrolyte structure was developed for proton-conducting SOFCs by using two layers of stable BaZr0.7Pr 0.1Y0.2O3 -δ to sandwich a highly-conductive but unstable BaCe0.8Y0.2O 3 -δ electrolyte layer. The sandwiched electrolyte structure showed good chemical stability in both CO2 and H2O atmosphere, indicating that the BZPY layers effectively protect the inner BCY electrolyte, while the BCY electrolyte alone decomposed completely under the same conditions. Fuel cell prototypes fabricated with the sandwiched electrolyte achieved a relatively high performance of 185 mW cm- 2 at 700 C, with a high electrolyte film conductivity of 4 × 10- 3 S cm- 1 at 600 C. © 2013 Elsevier B.V.

  2. LiGa(OTf)(sub 4) as an Electrolyte Salt for Li-Ion Cells

    Science.gov (United States)

    Reddy, V. Prakash; Prakash, G. K. Syria; Hu, Jinbo; Yan, Ping; Smart, Marshall; Bugga, ratnakumar; Chin, Keith; Surampudi, Subarao

    2008-01-01

    Lithium tetrakis(trifluoromethane sulfo - nato)gallate [abbreviated "LiGa(OTf)4" (wherein "OTf" signifies trifluoro - methanesulfonate)] has been found to be promising as an electrolyte salt for incorporation into both liquid and polymer electrolytes in both rechargeable and non-rechargeable lithium-ion electrochemical cells. This and other ingredients have been investigated in continuing research oriented toward im proving the performances of rechargeable lithium-ion electrochemical cells, especially at low temperatures. This research at earlier stages, and the underlying physical and chemical principles, were reported in numerous previous NASA Tech Briefs articles. As described in more detail in those articles, lithiumion cells most commonly contain nonaqueous electrolyte solutions consisting of lithium hexafluorophosphate (LiPF6) dissolved in mixtures of cyclic and linear alkyl carbonates, including ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), and ethyl methyl carbonate (EMC). Although such LiPF6-based electrolyte solutions are generally highly ionically conductive and electrochemically stable, as needed for good cell performance, there is interest in identifying alternate lithium electrolyte salts that, relative to LiPF6, are more resilient at high temperature and are less expensive. Experiments have been performed on LiGa(OTf)4 as well as on several other candidate lithium salts in pursuit of this interest. As part of these experiments, LiGa(OTf)4 was synthesized by the reaction of Ga(OTf)3 with an equimolar portion of LiOTf in a solvent consisting of anhydrous acetonitrile. Evaporation of the solvent yielded LiGa(OTf)4 as a colorless crystalline solid. The LiGa(OTf)4 and the other salts were incorporated into solutions with PC and DMC. The resulting electrolyte solutions exhibited reasonably high ionic conductivities over a relatively wide temperature range down to 40 C (see figure). In cyclic

  3. Preparation of electrolyte membranes for micro tubular solid oxide fuel cells

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Yttria-stabilized zirconia (YSZ) micro tubular electrolyte membranes for solid oxide fuel cells (SOFCs) were prepared via the combined wet phase inversion and sintering technique. The as-derived YSZ mi- cro tubes consist of a thin dense skin layer and a thick porous layer that can serve as the electrode of fuel cells. The dense and the porous electrolyte layers have the thickness of 3-5 μm and 70-90 μm, respectively, while the inner surface porosity of the porous layer is higher than 28.1%. The two layers are perfectly integrated together to preclude the crack or flake of electrolyte film from the electrode. The presented method possesses distinct advantages such as technological simplicity, low cost and high reliability, and thus provides a new route for the preparation of micro tubular SOFCs.

  4. Novel Semiconductor-Liquid Heterojunction Solar Cells Based on Cuprous Oxide and Iodine Electrolyte

    International Nuclear Information System (INIS)

    Graphical abstract: Display Omitted -- Highlights: •A novel Cu2O-electrolyte heterojunction solar cell was fabricated on a Cu foil substrate. •The novel solar cell was composed of a Cu2O electrode, electrolyte, and a Pt electrode. •A chemical oxidation method was used to fabricate coral-shaped Cu2O structures. •The influence of various iodine concentrations on device efficiency was studied. -- ABSTRACT: In this study, we report a novel cuprous oxide-electrolyte heterojunction solar cell fabricated on a copper foil substrate. A chemical oxidation method was used to fabricate a cuprous oxide electrode that was then combined with an electrolyte and platinum electrode to form a cuprous oxide-electrolyte heterojunction solar cell. Various analytic technologies were employed to characterize the cuprous oxide electrodes. Scanning electron microscopy (SEM) was employed to observe the surface morphology; energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) were used to characterize the material properties; and ultraviolet-visible (UV-vis) spectroscopy was used to analyze the optical properties of the cuprous oxide. The results show that the particle size of the cuprous oxide ranged from approximately 1–2 μm, which agglomerated and formed coral-shaped structures with lengths and widths of 10–20 and 5–6 μm, respectively, and with absorption wavelengths of 300 to 640 nm. The cuprous oxide-electrolyte heterojunction solar cell was also characterized, and the influence of various iodine (I2) concentrations on device efficiency was studied. The results show that when the I2 concentration of the electrolyte was 10 mM, the short-circuit current density, open-circuit voltage, fill factor, and device conversion efficiency of the cuprous oxide-electrolyte heterojunction solar cell were 3.52 mA/cm2, 0.64 V, 0.32, and 0.72%, respectively

  5. Development of Large-Format Lithium-Ion Cells with Silicon Anode and Low Flammable Electrolyte

    Science.gov (United States)

    Wu, James J.; Hernandez-Lugo, D. M.; Smart, M. C.; Ratnakumar, B. V.; Miller, T. B.; Lvovich, V. F.; Lytle, J. K.

    2014-01-01

    NASA is developing safe, high energy and high capacity lithium-ion cell designs and batteries for future missions under NASAs Advanced Space Power System (ASPS) project. Advanced cell components, such as high specific capacity silicon anodes and low-flammable electrolytes have been developed for improving the cell specific energy and enhancing safety. To advance the technology readiness level, we have developed large-format flight-type hermetically sealed battery cells by incorporating high capacity silicon anodes, commercially available lithium nickel, cobalt, aluminum oxide (NCA) cathodes, and low-flammable electrolytes. In this report, we will present the performance results of these various battery cells. In addition, we will also discuss the post-test cell analysis results as well.

  6. Spatial control of the energy metabolism of yeast cells through electrolytic generation of oxygen

    Science.gov (United States)

    Warnke, Christian; Mair, Thomas; Witte, Hartmut; Reiher, Antje; Hauser, Marcus J. B.; Krost, Alois

    2009-12-01

    The metabolic dynamics of yeast cells is controlled by electric pulses delivered through a spatially extended yeast cell/Au electrode interface. Concomitant with voltage pulses, oxygen is generated electrolytically at the electrode surface and delivered to the cells. The generation of oxygen was investigated in dependence of the applied voltage, width of the voltage pulses and temperature of the electrolytic solution. The local oxygen pulses at the electrodes lead to a transient activation of the aerobic energy metabolism of the yeast cells causing a perturbation in their energy balance. The effect of these local perturbations on the temporal dynamics of glycolysis in yeast cells is quantified in dependence of the energy state of cells.

  7. Spatial control of the energy metabolism of yeast cells through electrolytic generation of oxygen

    International Nuclear Information System (INIS)

    The metabolic dynamics of yeast cells is controlled by electric pulses delivered through a spatially extended yeast cell/Au electrode interface. Concomitant with voltage pulses, oxygen is generated electrolytically at the electrode surface and delivered to the cells. The generation of oxygen was investigated in dependence of the applied voltage, width of the voltage pulses and temperature of the electrolytic solution. The local oxygen pulses at the electrodes lead to a transient activation of the aerobic energy metabolism of the yeast cells causing a perturbation in their energy balance. The effect of these local perturbations on the temporal dynamics of glycolysis in yeast cells is quantified in dependence of the energy state of cells

  8. Continuous measurement of oxygen activities in the radioactive sodium of a reactor by solid electrolyte cells

    International Nuclear Information System (INIS)

    The haviour of electrochemical cells with disk-shaped solid electrolytes has been investigated for the measurement of oxygen activities in sodium. A summary is given of the cell characteristics determined in operating about 50 cells in nonradioactive sodium. The influence of radioactive irradiation on the cell record has been studied in model experiments using X- and gamma-ray sources. A cell construction which meets the requirements of reactor circuits has been tested for its reliability. Three cells tested in a nonradioactive sodium loop were subsequently operated in the primary circuit of the reactor BR-10. No influence of the radioactivity of sodium on the cell potential could be observed. (author)

  9. Polymer electrolyte membrane degradation and mobility in fuel cells : a solid-state NMR investigation

    OpenAIRE

    Ghassemzadeh Khoshkroodi, Lida

    2010-01-01

    It is generally believed that fuel cells will play an important role in energy technology already in the near future. Operating polymer electrolyte membrane fuel cells (PEMFCs) at temperatures higher than 100 °C and reduced humidity is anticipated to avoid most of the shortcomings associated with the low-temperature fuel cell operation, such as CO poisoning of the electrode catalysts, slow electrode kinetics of the oxygen reduction reaction and expensive water/thermal management. To date, the...

  10. Computational fluid dynamics modelling of a polymer electrolyte membrane fuel cell under transient automotive operations

    OpenAIRE

    Choopanya, Pattarapong

    2016-01-01

    A polymer electrolyte membrane (PEM) fuel cell is probably the most promising technology that will replace conventional internal combustion engines in the near future. As a primary power source for an automobile, the transient performance of a PEM fuel cell is of prime importance. In this thesis, a comprehensive, three-dimensional, two-phase, multi-species computational fuel cell dynamics model is developed in order to investigate the effect of flow-field design on the magnitude of current ov...

  11. Solidification of liquid electrolyte with imidazole polymers for quasi-solid-state dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Quasi-solid-state electrolytes were prepared by employing the imidazole polymers to solidify the liquid electrolyte containing lithium iodide, iodine and ethylene carbonate (EC)/propylene carbonate (PC) mixed solvent. The ionic conductivity and diffusion behavior of triiodide in the quasi-solid-state electrolytes were examined in terms of the polymer content. Application of the quasi-solid-state electrolytes to the dye-sensitized solar cells, the maximum energy conversion efficiency of 7.6% (AM 1.5, 100 mW cm-2) was achieved. The dependence of the photovoltaic performance on the polymer content and on the different anions of the imidazole polymers was studied by electrochemical impedance spectroscopy and cyclic voltammetry. The results indicate the charge transfer behaviors occurred at nanocrystalline TiO2/electrolyte and Pt/electrolyte interface play an important role in influencing the photovoltaic performance of quasi-solid-state dye-sensitized solar cells

  12. Solidification of liquid electrolyte with imidazole polymers for quasi-solid-state dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang Miao [Beijing National laboratory for Molecular Sciences, Key laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China); Lin Yuan [Beijing National laboratory for Molecular Sciences, Key laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080 (China)], E-mail: linyuan@iccas.ac.cn; Zhou Xiaowen; Xiao Xurui [Beijing National laboratory for Molecular Sciences, Key laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080 (China); Yang Lei [Beijing National laboratory for Molecular Sciences, Key laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China); Feng Shujing; Li Xueping [Beijing National laboratory for Molecular Sciences, Key laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080 (China)

    2008-01-15

    Quasi-solid-state electrolytes were prepared by employing the imidazole polymers to solidify the liquid electrolyte containing lithium iodide, iodine and ethylene carbonate (EC)/propylene carbonate (PC) mixed solvent. The ionic conductivity and diffusion behavior of triiodide in the quasi-solid-state electrolytes were examined in terms of the polymer content. Application of the quasi-solid-state electrolytes to the dye-sensitized solar cells, the maximum energy conversion efficiency of 7.6% (AM 1.5, 100 mW cm{sup -2}) was achieved. The dependence of the photovoltaic performance on the polymer content and on the different anions of the imidazole polymers was studied by electrochemical impedance spectroscopy and cyclic voltammetry. The results indicate the charge transfer behaviors occurred at nanocrystalline TiO{sub 2}/electrolyte and Pt/electrolyte interface play an important role in influencing the photovoltaic performance of quasi-solid-state dye-sensitized solar cells.

  13. Flow maldistribution in the anode of a polymer electrolyte membrane electrolysis cell employing interdigitated channels

    DEFF Research Database (Denmark)

    Olesen, Anders Christian; Kær, Søren Knudsen

    In this work a macroscopic, steady-state, three-dimensional, computational fluid dynamics model of the anode of a high-pressure polymer electrolyte membrane electrolysis cell (PEMEC) is presented. The developed model is used for studying the effect of employing an interdigitated, planar...

  14. Evaluation of the electrode/electrolyte contact quality in solid oxide fuel cells

    International Nuclear Information System (INIS)

    Highlights: ► A non-destructive in situ technique to evaluate the electrode–electrolyte contact. ► We set a parameter named as Effective Conducting Area that can quantify the coating quality. ► We offer a simple method for normalization of electrode polarization. - Abstract: Symmetrical cells have been prepared by depositing suspensions with different active powder concentrations (50% and 60% by weight respectively) of lanthanum strontium cobalt iron oxide (La0.6Sr0.4Co0.2Fe0.8O3−δ) on identical yttria stabilized zirconia pellets (LSCF/YSZ/LSCF). Their impedance characteristics are compared to that of a symmetrical cell with platinum electrodes deposited on a similar zirconia pellet (Pt/YSZ/Pt). The LSCF cells show different values of the electrolyte resistance. Referring to the electrolyte resistance obtained with the Pt cell and assuming that this value corresponds to almost perfect electrode/electrolyte contacts, it is possible to estimate the Effective Conducting Area (ECA) of the electrodes. The use of the ECA parameter allows a better comparison of the electrode polarizations.

  15. Modelling multiphase flow inside the porous media of a polymer electrolyte membrane fuel cell

    DEFF Research Database (Denmark)

    Berning, Torsten; Kær, Søren Knudsen

    2011-01-01

    Transport processes inside polymer electrolyte membrane fuel cells (PEMFC’s) are highly complex and involve convective and diffusive multiphase, multispecies flow through porous media along with heat and mass transfer and electrochemical reactions in conjunction with water transport through an el...

  16. Ionic Conducting Composite as Electrolyte for Low Temperature Solid Oxide Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang Xiaodi

    2010-07-01

    Solid oxide fuel cells (SOFCs) are considered as one of the most promising power generation technologies due to their high energy conversion efficiency, fuel flexibility and reduced pollution. The current SOFCs with yttria-stabilized zirconia (YSZ) electrolyte require high operation temperature (800-1000 deg C), which not only hinders their broad commercialization due to associated high cost and technological complications. Therefore, there is a broad interest in reducing the operating temperature of SOFCs. The key to development of low-temperature SOFCs (LTSOFCs) is to explore new electrolyte materials with high ionic conductivity at such low temperature (300-600 deg C). Recently, ceria-based composite electrolyte, consisting of doped cerium oxide mixed with a second phase (e.g. Na{sub 2}CO{sub 3}), has been investigated as a promising electrolyte for LTSOFCs. The ceria-based composite electrolyte has shown a high ionic conductivity and improved fuel cell performance below 600 deg C. However, at present the development of composite electrolyte materials and their application in LTSOFCs are still at an initial stage. This thesis aims at exploring new composite systems for LTSOFCs with superior properties, and investigates conductivity behavior of the electrolyte. Two composite systems for SOFCs have been studied in the thesis. In the first system, a novel concept of non-ceria-salt-composites electrolyte, LiAlO{sub 2} carbonate (Li{sub 2}CO{sub 3}-Na{sub 2}CO{sub 3}) composite electrolyte, was investigated for SOFCs. The LiAlO{sub 2}-carbonate electrolyte exhibited good conductivity and excellent fuel cell performances below 650 deg C. The ion transport mechanism of the LiAlO{sub 2}-carbonate composite electrolyte was studied. The results indicated that the high ionic conductivity relates to the interface effect between oxide and carbonate. In the second system, we reported a novel core-shell samarium-doped ceria (SDC)/Na{sub 2}CO{sub 3} nano composite which is

  17. Thin film galvanic cell with RbAg4I5 solid electrolyte

    International Nuclear Information System (INIS)

    In order to decrease the size and weight and to increase the specific capacity and energy of galvanic cells, some solid electrolytes in the form of thin films are proposed. The galvanic cells were prepared by a combined method: the cathodic and anodic materials (Te and Ag) were evaporated under vacuo to cover an electrolyte layer, the latter being obtained by impregnating the porous materials with RbAg4I5 acetonic solution. The most specific charge curves of the galvanic cells at various current densities are given: specific energy of the samples was 0.2 to 0.7 watt-h/kg, their capacity being 0.1 to 0.2 mah. Behaviour of the cells when stored (that of Ag(RbAg4I5) interface in particular) was investigated, namely, the effect of the storage time on the capacity and internal resistance of the galvanic cell

  18. Dye-sensitized solar cells and solar module using polymer electrolytes: Stability and performance investigations

    Directory of Open Access Journals (Sweden)

    Jilian Nei de Freitas

    2006-01-01

    Full Text Available We present recent results on solid-state dye-sensitized solar cell research using a polymer electrolyte based on a poly(ethylene oxide derivative. The stability and performance of the devices have been improved by a modification in the method of assembly of the cells and by the addition of plasticizers in the electrolyte. After 30 days of solar irradiation (100 mW cm-2 no changes in the cell's efficiency were observed using this new method. The effect of the active area size on cell performance and the first results obtained for the first solar module composed of 4.5 cm2 solid-state solar cells are also presented.

  19. Influence of electrolytes and membranes on cell operation for syn-gas production

    Energy Technology Data Exchange (ETDEWEB)

    Eric J. Dufek; Tedd E. Lister; Michael E. McIlwain

    2012-02-01

    The impact of membrane type and electrolyte composition for the electrochemical generation of synthesis gas (CO + H2) using a Ag gas diffusion electrode are presented. Changing from a cation exchange membrane to an anion exchange membrane (AEM) extended the cell operational time at low Ecell values (up to 4x) without impacting product composition. The use of KOH as the catholyte decreased the Ecell and resulted in a minimum electrolyte cost reduction of 39%. The prime factor in determining operational time at low Ecell values was the ability to maintain a sufficiently high anolyte pH.

  20. Fabrication of Monolithic Dye-Sensitized Solar Cell Using Ionic Liquid Electrolyte

    Directory of Open Access Journals (Sweden)

    Seigo Ito

    2012-01-01

    Full Text Available To improve the durability of dye-sensitized solar cells (DSCs, monolithic DSCs with ionic liquid electrolyte were studied. Deposited by screen printing, a carbon layer was successfully fabricated that did not crack or peel when annealing was employed beforehand. Optimized electrodes exhibited photovoltaic characteristics of 0.608 V open-circuit voltage, 6.90 cm−2 mA short-circuit current, and 0.491 fill factor, yielding 2.06% power conversion efficiency. The monolithic DSC using ionic liquid electrolyte was thermally durable and operated stably for 1000 h at 80°C.

  1. Electrodes/electrolyte interfaces in the presence of a surface-modified photopolymer electrolyte: application in dye-sensitized solar cells.

    Science.gov (United States)

    Sacco, Adriano; Bella, Federico; De La Pierre, Stefano; Castellino, Micaela; Bianco, Stefano; Bongiovanni, Roberta; Pirri, Candido Fabrizio

    2015-04-01

    Since hundreds of studies on photoanodes and cathodes show that the electrode/electrolyte interfaces represent a key aspect at the base of dye-sensitized solar cell (DSSC) performances, it is reported here that these interfaces can be managed by a smart design of the spatial composition of quasi-solid electrolytes. By means of a cheap, rapid, and green process of photoinduced polymerization, composition-tailored polymer electrolyte membranes (PEMs) with siloxane-enriched surfaces are prepared, and their properties are thoroughly described. When assembled in DSSCs, the interfacial action promoted by the composition-tailored PEMs enhances the photocurrent and fill factor values, thus increasing the global photovoltaic conversion efficiency with respect to the non-modified PEMs. Moreover, the presence of the siloxane-chain-enriched surface increases the hydrophobicity and reduces the water vapor permeation into the device, thus enhancing the cell's durability. PMID:25677499

  2. Aqueous liquid feed organic fuel cell using solid polymer electrolyte membrane

    Science.gov (United States)

    Surampudi, Subbarao (Inventor); Narayanan, Sekharipuram R. (Inventor); Vamos, Eugene (Inventor); Frank, Harvey A. (Inventor); Halpert, Gerald (Inventor); Olah, George A. (Inventor); Prakash, G. K. Surya (Inventor)

    1997-01-01

    A liquid organic fuel cell is provided which employs a solid electrolyte membrane. An organic fuel, such as a methanol/water mixture, is circulated past an anode of a cell while oxygen or air is circulated past a cathode of the cell. The cell solid electrolyte membrane is preferably fabricated from Nafion.TM.. Additionally, a method for improving the performance of carbon electrode structures for use in organic fuel cells is provided wherein a high surface-area carbon particle/Teflon.TM.-binder structure is immersed within a Nafion.TM./methanol bath to impregnate the electrode with Nafion.TM.. A method for fabricating an anode for use in a organic fuel cell is described wherein metal alloys are deposited onto the electrode in an electro-deposition solution containing perfluorooctanesulfonic acid. A fuel additive containing perfluorooctanesulfonic acid for use with fuel cells employing a sulfuric acid electrolyte is also disclosed. New organic fuels, namely, trimethoxymethane, dimethoxymethane, and trioxane are also described for use with either conventional or improved fuel cells.

  3. Diffuse layer effects on the current in galvanic cells containing supporting electrolyte

    International Nuclear Information System (INIS)

    We study the effect of an inert supporting electrolyte on the steady-state ionic current through galvanic cells by solving the full Poisson-Nernst-Planck transport equation coupled to the generalized Frumkin-Butler-Volmer boundary equation for the electrochemical charge transfer at the electrodes. Consequently, the model presented here allows for non-zero space charge densities locally at the electrodes, thus extending the frequently used models based on the local electroneutrality condition by including diffuse layer (DL) effects. This extension is necessary since the DLs determine the ion concentration and electrical field at the reaction planes, which uniquely determine the charge transfer at the electrodes. In this work we present numerical results for systems which contain added inert supporting electrolyte using finite element discretization and compare those with semi-analytical results obtained using singular perturbation theory (limit of negligibly thin DLs). In case of negligibly thin DLs the presence of supporting electrolyte will introduce a limiting current below the classical diffusion-limiting current. Just as for systems without supporting electrolyte, the supporting electrolyte induced limiting current formally does not occur for systems having non-negligibly thin double DLs. For thin, however still finite, double layers this limit can still be seen as a steepening of the polarization curve for current vs. voltage.

  4. A novel polymer gel electrolyte based on cyanoethylated cellulose for dye-sensitized solar cells

    International Nuclear Information System (INIS)

    A polymer gel electrolyte with the cyanoethylated hydroxypropyl cellulose (CN-HPC) as polymer matrix was prepared and applied in dye-sensitized solar cells (DSSCs). The ionic conductivities of the gel electrolytes based on LiI/I2 and 1-methyl-3-hexylimidazolium iodide (MHII)/I2 as the I−/I3− redox couple were determined, being 2.94 mS cm−1 and 2.46 mS cm−1 with the respective diffusion constants of I3− (Dapp) of 2.54 × 10−6 cm2 S−1, 2.15 × 10−6 cm2 S−1. Under the optimized condition, the overall conversion efficiencies of quasi-solid DSSCs were determined to be 7.40% based on a triphenylamine dye (SD2) and 7.55% based on a ruthenium dye (N719), which is 94% of those with liquid electrolyte.

  5. Transfer printing of thin electrolyte layers in solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Prica, M.; Kendall, K. [Keele Univ. (United Kingdom). Centre for Inorganic Chemistry and Materials Science; Painter, M. [Cookson Matthey, Stoke-on-Trent (United Kingdom)

    1995-12-31

    A transfer printing method for depositing micron and potentially submicron layers on a substrate to form a solid oxide fuel cell has been developed. This method is advantageous because it is economic and applies to planar, tubular and corrugated geometries. This paper reports the study of a 1.2 {micro}m layer of yttria-stabilized zirconia electrolyte deposited onto a nickel/ yttria-stabilized zirconia cermet tube with an outside diameter of 2.5 mm, where the cermet was either in the pre-fired or fired state. The electrolyte/cermet were fired at 1,500 C for one hour. Preliminary tests carried out on the fired tube show that the electrolyte is thin and uniform.

  6. Development of high efficiency 100% aqueous cobalt electrolyte dye-sensitised solar cells.

    Science.gov (United States)

    Ellis, Hanna; Jiang, Roger; Ye, Sofie; Hagfeldt, Anders; Boschloo, Gerrit

    2016-03-28

    In this study we report the application of three cobalt redox shuttles in 100% aqueous electrolyte dye-sensitised solar cells (DSCs). By using chloride as a counter-ion for cobalt bipyridine, cobalt phenanthroline and cobalt bipyridine pyrazole, the redox shuttles were made water soluble; no surfactant or further treatment was necessary. A simple system of merely the redox shuttles and 1-methylbenzimidazole (MBI) in water as an electrolyte in combination with an organic dye and a mesoporous PEDOT counter electrode was optimised. The optimisation resulted in an average efficiency of 5.5% (record efficiency of 5.7%) at 1 sun. The results of this study present promising routes for further improvements of aqueous cobalt electrolyte DSCs. PMID:26931779

  7. Evaluation of lanthanum tungstates as electrolytes for proton conductors Solid Oxide Fuel Cells

    Science.gov (United States)

    Zayas-Rey, M. J.; dos Santos-Gómez, L.; Porras-Vázquez, J. M.; Losilla, E. R.; Marrero-López, D.

    2015-10-01

    La27W4NbO55-δ (LWNO) has been tested as electrolyte for proton conductor Solid Oxide Fuel Cells (PC-SOFCs). For this purpose, different electrodes and composite electrodes are considered, including: La0.8Sr0.2MnO3-δ, La0.6Sr0.4Co1-xFexO3-δ, La0.75Sr0.25Cr0.5Mn0.5O3-δ, SrFe0.75Nb0.25O3-δ and NiO. Chemical compatibility between the cell components is investigated by X-ray powder diffraction (XRPD) and energy dispersive spectroscopy (EDS). Furthermore, area specific resistance (ASR) for the different electrodes is determined in symmetrical cells by impedance spectroscopy. XRPD and EDS analysis does not reveal significant bulk reactivity between most of these electrodes and LWNO electrolyte in the typical operating temperature range of an SOFC (600-900 °C). However, minor interdiffusion of elements at the electrolyte/electrode interface has negative effects on both the ohmic losses and electrode polarization of the cells. ASR values are significantly improved by using a porous buffer layer of Ce0.8Gd0.2O1.9 (CGO), deposited between the electrolyte and electrode materials, to prevent reactivity. A single cell with a 350 μm-thick electrolyte, NiO-CGO and La0.6Sr0.4Co0.8Fe0.2O3-δ-CGO composite as anode and cathode, respectively, generates maximum power densities of 140 and 18 mWcm-2 at 900 and 650 °C, respectively.

  8. Design of a single chambered microbial electrolytic cell reactor for production of biohydrogen from rice straw hydrolysate.

    Science.gov (United States)

    Gupta, Pratima; Parkhey, Piyush

    2015-06-01

    Rice straw was pretreated using a microwave-assisted alkali pretreatment method. Cellulose recovery was approximately 82 %. This material was hydrolysed in an optimized enzymatic saccharification reaction using cellulase from Lysinibacillus sphaericus. This resulted in saccharification of 49 % of cellulosic biomass into glucose. A single chambered microbial electrolytic cell reactor of volume 2l was built using acrylic plastic sheets with graphite sheet as anode and a stainless-steel mesh as cathode. Shewanella putrefaciens was used as exoelectrogen to oxidize rice straw hydrolysate in the reactor for electrohydrogenesis. The maximum H2 yield obtained was 801 ml H2 g(-1) COD removal. Coulombic efficiency of 88 %, cathodic H2 recovery of 58 % and total H2 recovery of 51 % with an energy efficiency of 74 % were recorded. PMID:25650347

  9. Ultrasonic-assisted ac etching of aluminum foils for electrolytic capacitor electrodes with enhanced capacitance

    International Nuclear Information System (INIS)

    ac etching of high-purity aluminum foils in hybrid acids including hydrochloric acid, sulphuric acid and oxalic acid was investigated and the effects of ultrasonic-assisted stirring on the performances of the etched foils were investigated in this work. Scanning electron microscopy (SEM) was used for observation of the etched foils. Compared with the classically used mechanical stirring (magnetic stirring), the assistance of ultrasonic increased the performance of the etched foil. With 20 V forming voltage, the static capacitance and bending strength of the foils etched with ultrasonic stirring reached 76.5 μF cm-2 and 98 times compared with 71.2 μF cm-2 and 85 times respectively for the foils fabricated with magnetic stirring using 100 μm aluminum foils. The performance enhancement with the assistance of ultrasonic is probably due to the cavitation effects which are beneficial for the remove of protective layer and the dispersion effects which reduce concentration polarization in the bulk etchant solutions.

  10. Novel chemically cross-linked solid state electrolyte for dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Yin Xiong; Tan Weiwei; Xiang Wangchun [Key Laboratory of Photochemistry, Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)] [Graduate School of Chinese Academy of Sciences, Beijing 100039 (China); Lin Yuan, E-mail: Linyuan@iccas.ac.c [Key Laboratory of Photochemistry, Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Zhang Jingbo, E-mail: jbzhang@iccas.ac.c [Key Laboratory of Photochemistry, Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Xiao Xurui; Li Xueping; Zhou Xiaowen; Fang Shibi [Key Laboratory of Photochemistry, Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)

    2010-08-01

    Poly(vinylpyridine-co-ethylene glycol methyl ether methacrylate) (P(VP-co-MEOMA)) and {alpha},{omega}-diiodo poly(ethylene oxide-co-propylene oxide) (I[(EO){sub 0.8}-co-(PO){sub 0.2}]{sub y}I) were synthesized and used as chemically cross-linked precursors of the electrolyte for dye-sensitized solar cells. Meanwhile, {alpha}-iodo poly(ethylene oxide-co-propylene oxide) methyl ether (CH{sub 3}O[(EO){sub 0.8}-co-(PO){sub 0.2}]{sub x}I) was synthesized and added into the electrolyte as an internal plasticizer. Novel polymer electrolyte resulting from chemically cross-linked precursors was obtained by the quaterisation at 90 {sup o}C for 30 min. The characteristics for this kind of electrolyte were investigated by means of ionic conductivity, thermogravimetric and photocurrent-voltage. The ambient ionic conductivity was significantly enhanced to 2.3 x 10{sup -4} S cm{sup -1} after introducing plasticizer, modified-ionic liquid. The weight loss of the solid state electrolyte at 200 {sup o}C was 1.8%, and its decomposition temperature was 287 {sup o}C. Solid state dye-sensitized solar cell based on chemically cross-linked electrolyte presented an overall conversion efficiency of 2.35% under AM1.5 irradiation (100 mW cm{sup -2}). The as-fabricated device maintained 88% of its initial performance at room temperature even without sealing for 30 days, showing a good stability.

  11. Composite electrolyte with proton conductivity for low-temperature solid oxide fuel cell

    International Nuclear Information System (INIS)

    In the present work, cost-effective nanocomposite electrolyte (Ba-SDC) oxide is developed for efficient low-temperature solid oxide fuel cells (LTSOFCs). Analysis has shown that dual phase conduction of O−2 (oxygen ions) and H+ (protons) plays a significant role in the development of advanced LTSOFCs. Comparatively high proton ion conductivity (0.19 s/cm) for LTSOFCs was achieved at low temperature (460 °C). In this article, the ionic conduction behaviour of LTSOFCs is explained by carrying out electrochemical impedance spectroscopy measurements. Further, the phase and structure analysis are investigated by X-ray diffraction and scanning electron microscopy techniques. Finally, we achieved an ionic transport number of the composite electrolyte for LTSOFCs as high as 0.95 and energy and power density of 90% and 550 mW/cm2, respectively, after sintering the composite electrolyte at 800 °C for 4 h, which is promising. Our current effort toward the development of an efficient, green, low-temperature solid oxide fuel cell with the incorporation of high proton conductivity composite electrolyte may open frontiers in the fields of energy and fuel cell technology

  12. Composite electrolyte with proton conductivity for low-temperature solid oxide fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Raza, Rizwan, E-mail: razahussaini786@gmail.com [Department of Physics, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Department of Energy Technology, Royal Institute of Technology, KTH, Stockholm 10044 (Sweden); Ahmed, Akhlaq; Akram, Nadeem; Saleem, Muhammad; Niaz Akhtar, Majid; Ajmal Khan, M.; Abbas, Ghazanfar; Alvi, Farah; Yasir Rafique, M. [Department of Physics, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Sherazi, Tauqir A. [Department of Chemistry, COMSATS Institute of Information Technology, Abbotabad 22060 (Pakistan); Shakir, Imran [Sustainable Energy Technologies (SET) center, College of Engineering, King Saud University, PO-BOX 800, Riyadh 11421 (Saudi Arabia); Mohsin, Munazza [Department of Physics, Lahore College for Women University, Lahore, 54000 (Pakistan); Javed, Muhammad Sufyan [Department of Physics, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Department of Applied Physics, Chongqing University, Chongqing 400044 (China); Zhu, Bin, E-mail: binzhu@kth.se, E-mail: zhubin@hubu.edu.cn [Department of Energy Technology, Royal Institute of Technology, KTH, Stockholm 10044 (Sweden); Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Faculty of Physics and Electronic Science/Faculty of Computer and Information, Hubei University, Wuhan, Hubei 430062 (China)

    2015-11-02

    In the present work, cost-effective nanocomposite electrolyte (Ba-SDC) oxide is developed for efficient low-temperature solid oxide fuel cells (LTSOFCs). Analysis has shown that dual phase conduction of O{sup −2} (oxygen ions) and H{sup +} (protons) plays a significant role in the development of advanced LTSOFCs. Comparatively high proton ion conductivity (0.19 s/cm) for LTSOFCs was achieved at low temperature (460 °C). In this article, the ionic conduction behaviour of LTSOFCs is explained by carrying out electrochemical impedance spectroscopy measurements. Further, the phase and structure analysis are investigated by X-ray diffraction and scanning electron microscopy techniques. Finally, we achieved an ionic transport number of the composite electrolyte for LTSOFCs as high as 0.95 and energy and power density of 90% and 550 mW/cm{sup 2}, respectively, after sintering the composite electrolyte at 800 °C for 4 h, which is promising. Our current effort toward the development of an efficient, green, low-temperature solid oxide fuel cell with the incorporation of high proton conductivity composite electrolyte may open frontiers in the fields of energy and fuel cell technology.

  13. Anodic Bubble Behavior and Voltage Drop in a Laboratory Transparent Aluminum Electrolytic Cell

    Science.gov (United States)

    Zhao, Zhibin; Wang, Zhaowen; Gao, Bingliang; Feng, Yuqing; Shi, Zhongning; Hu, Xianwei

    2016-06-01

    The anodic bubbles generated in aluminum electrolytic cells play a complex role to bath flow, alumina mixing, cell voltage, heat transfer, etc., and eventually affect cell performance. In this paper, the bubble dynamics beneath the anode were observed for the first time from bottom view directly in a similar industrial electrolytic environment, using a laboratory-scale transparent aluminum electrolytic cell. The corresponding cell voltage was measured simultaneously for quantitatively investigating its relevance to bubble dynamics. It was found that the bubbles generated in many spots that increased in number with the increase of current density; the bubbles grew through gas diffusion and various types of coalescences; when bubbles grew to a certain size with their surface reaching to the anode edge, they escaped from the anode bottom suddenly; with the increase of current density, the release frequency increases, and the size of these bubbles decreases. The cell voltage was very consistent with bubble coverage, with a high bubble coverage corresponding to a higher cell voltage. At low current density, the curves of voltage and coverage fluctuated in a regularly periodical pattern, while the curves became more irregular at high current density. The magnitude of voltage fluctuation increased with current density first and reached a maximum value at current density of 0.9 A/cm2, and decreased when the current density was further increased. The extra resistance induced by bubbles was found to increase with the bubble coverage, showing a similar trend with published equations.

  14. Cell Design for Electrochemical Characterizations of Metal-Ion Batteries in Organic and Aqueous Electrolyte.

    Science.gov (United States)

    Bani Hashemi, Amir; La Mantia, Fabio

    2016-08-16

    Understanding the gas evolution in batteries, caused by decomposition of the electrolyte, is of fundamental importance for improving the long-time performances and cycle life of the battery systems. In general, this phenomenon causes simultaneously an irreversible energy and charge loss, as well as an increase of the internal resistance. Here, we introduce a new cell design capable of performing electrochemical impedance spectroscopy (EIS) and differential electrochemical mass spectroscopy (DEMS) with high resolution. Detailed aspects of the cell fabrication and the different components of the cell are extensively explained. Impedance measurements were validated by using symmetric electrodes. The possibility of performing long-term DEMS measurements was tested on graphite electrodes in Ethylene Carbonate/Dimethyl Carbonate (1:1), 1 M LiPF6 as an electrolyte. Finally, the cell was used to detect hydrogen evolution on the zinc negative electrode of a zinc-ion battery based on copper hexacyanoferrate. PMID:27439309

  15. Mass transport aspects of polymer electrolyte fuel cells under two-phase flow conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, D.

    2007-03-15

    This well-illustrated, comprehensive dissertation by Dr. Ing. Denis Kramer takes an in-depth look at polymer electrolyte fuel cells (PEFC) and the possibilities for their application. First of all, the operating principles of polymer electrolyte fuel cells are described and discussed, whereby thermodynamics aspects and loss mechanisms are examined. The mass transport diagnostics made with respect to the function of the cells are discussed. Field flow geometry, gas diffusion layers and, amongst other things, liquid distribution, the influence of flow direction and the low-frequency behaviour of air-fed PEFCs are discussed. Direct methanol fuel cells are examined, as are the materials chosen. The documentation includes comprehensive mathematical and graphical representations of the mechanisms involved.

  16. Li-Ion Cells Employing Electrolytes With Methyl Propionate and Ethyl Butyrate Co-Solvents

    Science.gov (United States)

    Smart, Marshall C.; Bugga, Ratnakumar V.

    2011-01-01

    temperature range in MCMB-LiNiCoAlO2 and Li4Ti5O12-LiNi-CoAlO2 prototype cells. These electrolytes have enabled high rate performance at low temperature (i.e., up to 2.0C rates at -50 C and 5.0C rates at -40 C), and good cycling performance over a wide temperature range (i.e., from -40 to +70 C). Current efforts are focused upon improving the high temperature resilience of the methyl propionatebased system through the use of electrolyte additives, which are envisioned to improve the nature of the solid electrolyte interphase (SEI) layers.

  17. STABLE HIGH CONDUCTIVITY BILAYERED ELECTROLYTES FOR LOW TEMPERATURE SOLID OXIDE FUEL CELLS

    Energy Technology Data Exchange (ETDEWEB)

    Eric D. Wachsman; Keith L. Duncan

    2001-09-30

    Solid oxide fuel cells (SOFCs) are the future of energy production in America. They offer great promise as a clean and efficient process for directly converting chemical energy to electricity while providing significant environmental benefits (they produce negligible hydrocarbons, CO, or NO{sub x} and, as a result of their high efficiency, produce about one-third less CO{sub 2} per kilowatt hour than internal combustion engines). Unfortunately, the current SOFC technology, based on a stabilized zirconia electrolyte, must operate in the region of 1000 C to avoid unacceptably high ohmic losses. These high temperatures demand (a) specialized (expensive) materials for the fuel cell interconnects and insulation, (b) time to heat up to the operating temperature and (c) energy input to arrive at the operating temperature. Therefore, if fuel cells could be designed to give a reasonable power output at low to intermediate1 temperatures tremendous benefits may be accrued. At low temperatures, in particular, it becomes feasible to use ferritic steel for interconnects instead of expensive and brittle ceramic materials such as those based on LaCrO{sub 3}. In addition, sealing the fuel cell becomes easier and more reliable; rapid start-up is facilitated; thermal stresses (e.g., those caused by thermal expansion mismatches) are reduced; radiative losses ({approx}T{sup 4}) become minimal; electrode sintering becomes negligible and (due to a smaller thermodynamic penalty) the SOFC operating cycle (heating from ambient) would be more efficient. Combined, all these improvements further result in reduced initial and operating costs. The problem is, at lower temperatures the conductivity of the conventional stabilized zirconia electrolyte decreases to the point where it cannot supply electrical current efficiently to an external load. The primary objectives of the proposed research are to develop a stable high conductivity (> 0.05 S cm{sup -1} at {le} 550 C) electrolyte for lower

  18. Characterization of the CO sensitivity of electrode materials by solid electrolyte galvanic cells

    OpenAIRE

    Plashnitsa, Vladimir

    2004-01-01

    The voltage of a galvanic cell using stabilized zirconia as a solid electrolyte can exhibit deviations from the equilibrium value given by the Nernst equation, if oxygen together with traces of an oxidizable gas like CO is exposed to one of the electrodes of the cell. This is called the non-Nernstian voltage behaviour. The basic principle of operation is not yet finally cleared since the experimental results are in accordance with two theoretical approaches. Aiming at a better understanding o...

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

    DEFF Research Database (Denmark)

    Veltzé, Sune; Reddy Sudireddy, Bhaskar; Jørgensen, Peter Stanley; Zhang, Wei; Kuhn, Luise Theil; Holtappels, Peter; Ramos, Tania

    2013-01-01

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

  1. The use of additive manufacture for metallic bipolar plates in polymer electrolyte fuel cell stacks

    OpenAIRE

    Dawson, Richard; Patel, Anant; Rennie, Allan; White, Simon

    2014-01-01

    The bipolar plate is of critical importance to the efficient and long lasting operation of a polymer electrolyte fuel cell (PEMFC) stack. With advances in membrane electrode assembly (MEA) design greater attention has been focused on the bipolar plate and the important role it plays in performance and durability. Although carbon composite plates are a likely candidate for the mass introduction of fuel cells, it is metallic plates made from thin strip materials (typically 0.2 mm thick stainles...

  2. Hydrophobicity Patterning of Gas Diffusion Media for Polymer Electrolyte Fuel Cells

    OpenAIRE

    Biswas, Indro; Gazdzicki, Pawel; Tomas, Martin; Schulze, Mathias

    2014-01-01

    Polymer electrolyte fuel cells with their high gravimetric energy density face a water balance problem especially under variable loads, e.g. in automotive conditions: The excess product water needs to be removed from the fuel cell while maintaining a humidifed membrane. The gas diffusion layer, which also provides contact to the electro- chemically active components, has to achieve the passive management of the water balance. Heterogeneously hydrophobic gas diffusion media ...

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

    DEFF Research Database (Denmark)

    Veltzé, Sune; Reddy Sudireddy, Bhaskar; Jørgensen, Peter Stanley; Zhang, Wei; Kuhn, Luise Theil; Holtappels, Peter; Ramos, Tania

    2013-01-01

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

  4. Ionic gel electrolytes composite with SiO2 nanoparticles for quasi-solid-state dye-sensitized solar cells

    Science.gov (United States)

    Jin, Liguo; Liu, Taiyang; Wang, Chao

    2016-06-01

    Composite ionic gel electrolytes were facilely prepared by mixing ionic gel electrolytes with SiO2 nanoparticles. The dye-sensitized solar cells (DSSCs) assembled with the composite ionic gel electrolytes exhibit the higher photovoltaic performance and better durability compared to the original DSSCs based on pure ionic gel electrolytes. In particular, the DSSC assembled with the electrolytes containing 0.15 g of SiO2 shows superior J SC (14.4 mA cm-2), V OC (0.67 V), fill factor (0.69) and power conversion efficiency (6.71 %) (measured at AM 1.5, light intensity of 100 mW/cm2). The electrochemical impedance spectra, SEM and conductivity were used to characterize the composite ionic gel electrolytes.

  5. The effect of porosity on performance of phosphoric acid doped polybenzimidazole polymer electrolyte membrane fuel cell

    Science.gov (United States)

    Celik, Muhammet; Genc, Gamze; Elden, Gulsah; Yapici, Huseyin

    2016-03-01

    A polybenzimidazole (PBI) based polymer electrolyte fuel cells, which called high temperature polymer electrolyte fuel cells (HT-PEMS), operate at higher temperatures (120-200°C) than conventional PEM fuel cells. Although it is known that HT-PEMS have some of the significant advantages as non-humidification requirements for membrane and the lack of liquid water at high temperature in the fuel cell, the generated water as a result of oxygen reduction reaction causes in the degradation of these systems. The generated water absorbed into membrane side interacts with the hydrophilic PBI matrix and it can cause swelling of membrane, so water transport mechanism in a membrane electrode assembly (MEA) needs to be well understood and water balance must be calculated in MEA. Therefore, the water diffusion transport across the electrolyte should be determined. In this study, various porosity values of gas diffusion layers are considered in order to investigate the effects of porosity on the water management for two phase flow in fuel cell. Two-dimensional fuel cell with interdigitated flow-field is modelled using COMSOL Multiphysics 4.2a software. The operating temperature and doping level is selected as 160°C and 6.75mol H3PO4/PBI, respectively.

  6. The effect of porosity on performance of phosphoric acid doped polybenzimidazole polymer electrolyte membrane fuel cell

    Directory of Open Access Journals (Sweden)

    Celik Muhammet

    2016-01-01

    Full Text Available A polybenzimidazole (PBI based polymer electrolyte fuel cells, which called high temperature polymer electrolyte fuel cells (HT-PEMS, operate at higher temperatures (120-200°C than conventional PEM fuel cells. Although it is known that HT-PEMS have some of the significant advantages as non-humidification requirements for membrane and the lack of liquid water at high temperature in the fuel cell, the generated water as a result of oxygen reduction reaction causes in the degradation of these systems. The generated water absorbed into membrane side interacts with the hydrophilic PBI matrix and it can cause swelling of membrane, so water transport mechanism in a membrane electrode assembly (MEA needs to be well understood and water balance must be calculated in MEA. Therefore, the water diffusion transport across the electrolyte should be determined. In this study, various porosity values of gas diffusion layers are considered in order to investigate the effects of porosity on the water management for two phase flow in fuel cell. Two-dimensional fuel cell with interdigitated flow-field is modelled using COMSOL Multiphysics 4.2a software. The operating temperature and doping level is selected as 160°C and 6.75mol H3PO4/PBI, respectively.

  7. Methyl phosphate formation as a major degradation mode of direct methanol fuel cells with phosphoric acid based electrolytes

    DEFF Research Database (Denmark)

    Aili, David; Vassiliev, Anton; Jensen, Jens Oluf;

    2015-01-01

    Phosphoric acid and phosphoric acid doped polymer membranes are widely used as electrolytes in hydrogen based fuel cells operating at elevated temperatures. Such electrolytes have been explored for direct oxidation of methanol to further increase the versatility of the systems, however...

  8. Controllable deposition of gadolinium doped ceria electrolyte films by magnetic-field-assisted electrostatic spray deposition

    International Nuclear Information System (INIS)

    This paper describes a simple and low-temperature approach to fabrication of dense and crack-free gadolinium doped ceria (GDC) thin films with controllable deposition by a magnetic-field-assisted electrostatic spray deposition technique. The influences of external permanent magnets on the deposition of GDC films were investigated. The coating area deposited using two magnets with the same pole arrangement decreased in comparison with the case of no magnets, whereas the largest deposition area was obtained in the system of the opposite poles. Analysis of as-deposited films at 450 °C indicated the formation of uniform, smooth and dense thin films with a single-phase fluorite structure. The films produced in the system using same poles were thicker, smaller in crystallite size and smoother than those fabricated under other conditions. Additionally, the GDC film deposited using the same pole arrangement showed the maximum in electrical conductivity of about 2.5 × 10−2 S/cm at a low operating temperature of 500 °C. - Highlights: • Magnetic-field-assisted electrostatic spray allows a controllable coating. • Dense, crack-free thin films were obtained at low process temperature of 450 °C. • Control of deposition, thickness and uniformity is easy to achieve simultaneously. • Films from the same pole were thicker, smaller in crystal size and smoother. • The maximum conductivity of doped ceria film was 2.5 × 10−2 S/cm at 500 °C

  9. Gel polymer electrolyte lithium-ion cells with improved low temperature performance

    Energy Technology Data Exchange (ETDEWEB)

    Smart, M.C.; Ratnakumar, B.V.; Behar, A.; Whitcanack, L.D. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Yu, J.-S. [LG Chem/Research Park, P.O. Box 61Yu Song, Science Town, Daejon (Korea); Alamgir, M. [Compact Power, Inc., 1857 Technology Drive, Troy, MI 48083 (United States)

    2007-03-20

    For a number of NASA's future planetary and terrestrial applications, high energy density rechargeable lithium batteries that can operate at very low temperature are desired. In the pursuit of developing Li-ion batteries with improved low temperature performance, we have also focused on assessing the viability of using gel polymer systems, due to their desirable form factor and enhanced safety characteristics. In the present study we have evaluated three classes of promising liquid low-temperature electrolytes that have been impregnated into gel polymer electrolyte carbon-LiMn{sub 2}O{sub 4}-based Li-ion cells (manufactured by LG Chem. Inc.), consisting of: (a) binary EC + EMC mixtures with very low EC-content (10%), (b) quaternary carbonate mixtures with low EC-content (16-20%), and (c) ternary electrolytes with very low EC-content (10%) and high proportions of ester co-solvents (i.e., 80%). These electrolytes have been compared with a baseline formulation (i.e., 1.0 M LiPF{sub 6} in EC + DEC + DMC (1:1:1%, v/v/v), where EC, ethylene carbonate, DEC, diethyl carbonate, and DMC, dimethyl carbonate). We have performed a number of characterization tests on these cells, including: determining the rate capacity as a function of temperature (with preceding charge at room temperature and also at low temperature), the cycle life performance (both 100% DOD and 30% DOD low earth orbit cycling), the pulse capability, and the impedance characteristics at different temperatures. We have obtained excellent performance at low temperatures with ester-based electrolytes, including the demonstration of >80% of the room temperature capacity at -60 C using a C/20 discharge rate with cells containing 1.0 M LiPF{sub 6} in EC + EMC + MB (1:1:8%, v/v/v) (MB, methyl butyrate) and 1.0 M LiPF{sub 6} in EC + EMC + EB (1:1:8%, v/v/v) (EB, ethyl butyrate) electrolytes. In addition, cells containing the ester-based electrolytes were observed to support 5C pulses at -40 C, while still

  10. Allylic ionic liquid electrolyte-assisted electrochemical surface passivation of LiCoO2 for advanced, safe lithium-ion batteries

    Science.gov (United States)

    Mun, Junyoung; Yim, Taeeun; Park, Jang Hoon; Ryu, Ji Heon; Lee, Sang Young; Kim, Young Gyu; Oh, Seung M.

    2014-08-01

    Room-temperature ionic liquid (RTIL) electrolytes have attracted much attention for use in advanced, safe lithium-ion batteries (LIB) owing to their nonvolatility, high conductivity, and great thermal stability. However, LIBs containing RTIL-electrolytes exhibit poor cyclability because electrochemical side reactions cause problematic surface failures of the cathode. Here, we demonstrate that a thin, homogeneous surface film, which is electrochemically generated on LiCoO2 from an RTIL-electrolyte containing an unsaturated substituent on the cation (1-allyl-1-methylpiperidinium bis(trifluoromethanesulfonyl)imide, AMPip-TFSI), can avert undesired side reactions. The derived surface film comprised of a high amount of organic species from the RTIL cations homogenously covered LiCoO2 with a <25 nm layer and helped suppress unfavorable thermal reactions as well as electrochemical side reactions. The superior performance of the cell containing the AMPip-TFSI electrolyte was further elucidated by surface, electrochemical, and thermal analyses.

  11. Recent development of ceria-based (nano)composite materials for low temperature ceramic fuel cells and electrolyte-free fuel cells

    OpenAIRE

    Fan, Liangdong; Wang, Chengyang; Chen, Mingming; Zhu, Bin

    2013-01-01

    In the last ten years, the research of solid oxide fuel cells (SOFCs) or ceramic fuel cells (CFC) had focused on reducing the working temperature through the development of novel materials, especially the high ionic conductive electrolyte materials. Many progresses on single-phase electrolyte materials with the enhanced ionic conductivity have been made, but they are still far from the criteria of commercialization. The studies of ceria oxide based composite electrolytes give an alternative s...

  12. Performance of a direct glycerol fuel cell using KOH doped polybenzimidazole as electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, Ana P.; Linares, Jose J., E-mail: joselinares@unb.br [Universidade de Brasilia (UnB), Brasilia, DF (Brazil). Instituto de Quimica

    2014-03-15

    This paper studies the influence of the operating variables (glycerol concentration, temperature and feed rate) for a direct glycerol fuel cell fed with glycerol using polybenzimidazole (PBI) impregnated with KOH as electrolyte and Pt/C as catalyst. Temperature displays a beneficial effect up to 75 °C due to the enhanced conductivity and kinetics of the electrochemical reactions. The optimum cell feed corresponds to 1 mol L{sup -1} glycerol and 4 mol L{sup -1} KOH, supplying sufficient quantities of fuel and electrolyte without massive crossover nor mass transfer limitations. The feed rate increases the performance up to a limit of 2 mL min{sup -1}, high enough to guarantee the access of the glycerol and the exit of the products. Finally, the use of binary catalysts (PtRu/C and Pt{sub 3}Sn/C) is beneficial for increasing the cell performance. (author)

  13. Electric response of an electrolytic cell to a periodic excitation in the dc limit

    Energy Technology Data Exchange (ETDEWEB)

    Alexe-Ionescu, A.L. [Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, Corso Duca degli Abruzzo 24, 10129 Torino (Italy); University Politehnica of Bucharest, Faculty of Applied Sciences, Splaiul Independentei 313, 060042 Bucharest (Romania); Barbero, G. [Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, Corso Duca degli Abruzzo 24, 10129 Torino (Italy); Duarte, A.R. [Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, Corso Duca degli Abruzzo 24, 10129 Torino (Italy); Instituto de Física, Universidade de São Paulo, P.O. Box 66318, São Paulo 05314-970 (Brazil); Saracco, G. [Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, Corso Duca degli Abruzzo 24, 10129 Torino (Italy)

    2014-05-01

    We evaluate the electrical impedance of an electrolytic cell submitted to a low frequency external voltage. We show that in the limit where the circular frequency of the applied voltage, ω, is small with respect to Debye relaxation circular frequency, ω{sub D}, the response of the cell can be evaluated by means of a perturbational calculation, where the expansion parameter is x=ω/ω{sub D}. Simple expressions for the reactance and resistance in the dc limit of the electrolytic cell are obtained in the case where the electrodes are blocking and the diffusion coefficients of the negative and positive ions are equal. The case where the diffusion coefficients are different is also considered. In this framework, our analysis indicates that in the considered frequency range the effective diffusion coefficient coincides with the ambipolar diffusion coefficient. A possible extension of our approach to the case where the electrodes are not blocking is discussed too.

  14. Nanomaterials for Polymer Electrolyte Membrane Fuel Cells; Materials Challenges Facing Electrical Energy Storate

    Energy Technology Data Exchange (ETDEWEB)

    Gopal Rao, MRS Web-Editor; Yury Gogotsi, Drexel University; Karen Swider-Lyons, Naval Research Laboratory

    2010-08-05

    Symposium T: Nanomaterials for Polymer Electrolyte Membrane Fuel Cells Polymer electrolyte membrane (PEM) fuel cells are under intense investigation worldwide for applications ranging from transportation to portable power. The purpose of this seminar is to focus on the nanomaterials and nanostructures inherent to polymer fuel cells. Symposium topics will range from high-activity cathode and anode catalysts, to theory and new analytical methods. Symposium U: Materials Challenges Facing Electrical Energy Storage Electricity, which can be generated in a variety of ways, offers a great potential for meeting future energy demands as a clean and efficient energy source. However, the use of electricity generated from renewable sources, such as wind or sunlight, requires efficient electrical energy storage. This symposium will cover the latest material developments for batteries, advanced capacitors, and related technologies, with a focus on new or emerging materials science challenges.

  15. STABLE HIGH CONDUCTIVITY BILAYERED ELECTROLYTES FOR LOW TEMPERATURE SOLID OXIDE FUEL CELLS

    Energy Technology Data Exchange (ETDEWEB)

    Eric D. Wachsman

    2000-10-01

    Solid oxide fuel cells (SOFCs) are the future of energy production in America. They offer great promise as a clean and efficient process for directly converting chemical energy to electricity while providing significant environmental benefits (they produce negligible CO, HC, or NOx and, as a result of their high efficiency, produce about one-third less CO{sub 2} per kilowatt hour than internal combustion engines). Unfortunately, the current SOFC technology, based on a stabilized zirconia electrolyte, must operate in the region of 1000 C to avoid unacceptably high ohmic losses. These high temperatures demand (a) specialized (expensive) materials for the fuel cell interconnects and insulation, (b) time to heat up to the operating temperature and (c) energy input to arrive at the operating temperature. Therefore, if fuel cells could be designed to give a reasonable power output at lower temperatures tremendous benefits may be accrued, not the least of which is reduced cost. The problem is, at lower temperatures the conductivity of the conventional stabilized zirconia electrolyte decreases to the point where it cannot supply electrical current efficiently to an external load. The primary objectives of the proposed research is to develop a stable high conductivity (>0.05 S cm{sup -1} at 550 C) electrolyte for lower temperature SOFCs. This objective is specifically directed toward meeting the lowest (and most difficult) temperature criteria for the 21st Century Fuel Cell Program. Meeting this objective provides a potential for future transportation applications of SOFCs, where their ability to directly use hydrocarbon fuels could permit refueling within the existing transportation infrastructure. In order to meet this objective we are developing a functionally gradient bilayer electrolyte comprised of bismuth oxide on the air side and ceria on the fuel side. Bismuth oxide and doped ceria are among the highest ionic conducting electrolytes and in fact bismuth oxide based

  16. Solid oxide membrane-assisted controllable electrolytic fabrication of metal carbides in molten salt.

    Science.gov (United States)

    Zou, Xingli; Zheng, Kai; Lu, Xionggang; Xu, Qian; Zhou, Zhongfu

    2016-08-15

    Silicon carbide (SiC), titanium carbide (TiC), zirconium carbide (ZrC), and tantalum carbide (TaC) have been electrochemically produced directly from their corresponding stoichiometric metal oxides/carbon (MOx/C) precursors by electrodeoxidation in molten calcium chloride (CaCl2). An assembled yttria stabilized zirconia solid oxide membrane (SOM)-based anode was employed to control the electrodeoxidation process. The SOM-assisted controllable electrochemical process was carried out in molten CaCl2 at 1000 °C with a potential of 3.5 to 4.0 V. The reaction mechanism of the electrochemical production process and the characteristics of these produced metal carbides (MCs) were systematically investigated. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy analyses clearly identify that SiC, TiC, ZrC, and TaC carbides can be facilely fabricated. SiC carbide can be controlled to form a homogeneous nanowire structure, while the morphologies of TiC, ZrC, and TaC carbides exhibit porous nodular structures with micro/nanoscale particles. The complex chemical/electrochemical reaction processes including the compounding, electrodeoxidation, dissolution-electrodeposition, and in situ carbonization processes in molten CaCl2 are also discussed. The present results preliminarily demonstrate that the molten salt-based SOM-assisted electrodeoxidation process has the potential to be used for the facile and controllable electrodeoxidation of MOx/C precursors to micro/nanostructured MCs, which can potentially be used for various applications. PMID:27195950

  17. Tetrazole substituted polymers for high temperature polymer electrolyte fuel cells

    DEFF Research Database (Denmark)

    Henkensmeier, Dirk; My Hanh Duong, Ngoc; Brela, Mateusz;

    2015-01-01

    interesting for use in a high temperature fuel cell (HT PEMFC). Based on these findings, two polymers incorporating the proposed TZ groups were synthesised, formed into membranes, doped with PA and tested for fuel cell relevant properties. At room temperature, TZ-PEEN and commercial meta-PBI showed an...

  18. Extraction of water-soluble salts from used cathodic and board units of electrolytic cells of aluminium production

    International Nuclear Information System (INIS)

    Present article is devoted to study of the process of extraction of water-soluble salts from used cathodic and board units of electrolytic cells of aluminium production. Therefore the composition of water-soluble salts from used cathodic and board units of electrolytic cells of aluminium production was defined. The optimal parameters of extraction of water-soluble salts from used cathodic and board units of electrolytic cells of aluminium production were determined. The possibility of obtaining the soda ash and sodium fluoride from aqueous extracts of carbon graphite wastes of aluminium production was defined as well.

  19. Nano-precision combined process of electrolytic in-process dressing grinding and magnetic assisted polishing on optics glass material

    Institute of Scientific and Technical Information of China (English)

    Tae-Soo KWAK; Yong-Chul LEE; Gyung-Nyun KIM; Dae-Bong CHOI; Mikio YAMANOI; Hitoshi OHMORI

    2009-01-01

    This study is focused on the application of an effective fabrication method combining electrolytic in-process dressing(ELID) grinding and magnetic assisted polishing(MAP) to nano-precision mirror surface grinding on the optics glass-ceramic named Zerodure that is commonly used in precision optics components. The results show the variation of surface roughness after MAP processes utilizing Fe+CeO2, Fe+CeO2+diamond paste and Fe+diamond paste are applied to ELID ground surfaces. The MAP surface roughnesses for ELID ground surface roughnesses(Ra) of 52.1, 39.8 and 51.1 nm using #1200 grinding wheel are improved to 6.1, 4.6 and 1.9 nm, respectively. The surface roughness of MAP process using Fe+CeO2+diamond paste is superior to that using other processes. Moreover, it takes less than 10 min to conduct the MAP processes. The combined method suggested effectively reduces the working time to get the required surface qualities.

  20. U.S. DOE Progress Towards Developing Low-Cost, High Performance, Durable Polymer Electrolyte Membranes for Fuel Cell Applications

    OpenAIRE

    Dimitrios C. Papageorgopoulos; Reginald Tyler; Jason Marcinkoski; Kathi Epping Martin; Donna Lee Ho; Garland, Nancy L.; David Peterson; John Kopasz; Spendelow, Jacob S.; Greg J. Kleen; Cassidy Houchins

    2012-01-01

    Low cost, durable, and selective membranes with high ionic conductivity are a priority need for wide-spread adoption of polymer electrolyte membrane fuel cells (PEMFCs) and direct methanol fuel cells (DMFCs). Electrolyte membranes are a major cost component of PEMFC stacks at low production volumes. PEMFC membranes also impose limitations on fuel cell system operating conditions that add system complexity and cost. Reactant gas and fuel permeation through the membrane leads to decreased fuel ...

  1. Multifunctional graphene incorporated polyacrylamide conducting gel electrolytes for efficient quasi-solid-state quantum dot-sensitized solar cells

    Science.gov (United States)

    Duan, Jialong; Tang, Qunwei; Li, Ru; He, Benlin; Yu, Liangmin; Yang, Peizhi

    2015-06-01

    Pursuit of a high efficiency and stability has been a persistent objective for quantum dot-sensitized solar cells (QDSCs). Here we launch a strategy of synthesizing graphene implanted polyacrylamide (PAAm-G) conducting gel electrolytes for quasi-solid-state QDSCs. With an aim of elevating the dosage of S2-/Sx2- redox couples and therefore charge-transfer ability, both osmotic press across the PAAm-G and capillary force within the three-dimensional micropores are utilized as driving forces. A promising power conversion efficiency of 2.34% is recorded for the QDSCs by optimizing graphene dosage in the conducting gel electrolyte. The enhanced conversion efficiency of solar cell is attributed to the expanded catalytic area from counter electrolyte/electrolyte interface to both interface and the conducting gel electrolyte.

  2. Electrospun nanofibre composite polymer electrolyte fuel cell and electrolysis membranes

    OpenAIRE

    Sood, Rakhi; Cavaliere, Sara; Rozière, Jacques; Jones, Deborah

    2016-01-01

    International audience Large-scale commercialisation of Proton Exchange Membrane Fuel Cell (PEMFC) technology for automotive and stationary applications demands the development of a robust, durable and cost-effective materials. In this regard, ionomer membranes being present at the core of PEMFCs are required to maintain elevated proton conductivity, high mechanical strength and low gas permeability during the lifespan of the fuel cell. These challenges are addressed by investigating novel...

  3. DMAC and NMP as Electrolyte Additives for Li-Ion Cells

    Science.gov (United States)

    Smart, Marshall; Bugga, Ratnakumar; Lucht, Brett

    2008-01-01

    Dimethyl acetamide (DMAC) and N-methyl pyrrolidinone (NMP) have been found to be useful as high-temperature-resilience-enhancing additives to a baseline electrolyte used in rechargeable lithium-ion electrochemical cells. The baseline electrolyte, which was previously formulated to improve low-temperature performance, comprises LiPF6 dissolved at a concentration of 1.0 M in a mixture comprising equal volume proportions of ethylene carbonate, diethyl carbonate, and dimethyl carbonate. This and other electrolytes comprising lithium salts dissolved in mixtures of esters (including alkyl carbonates) have been studied in continuing research directed toward extending the lower limits of operating temperatures and, more recently, enhancing the high-temperature resilience of such cells. This research at earlier stages, and the underlying physical and chemical principles, were reported in numerous previous NASA Tech Briefs articles. Although these electrolytes provide excellent performance at low temperatures (typically as low as -40 C), when the affected Li-ion cells are subjected to high temperatures during storage and cycling, there occur irreversible losses of capacity accompanied by power fade and deterioration of low-temperature performance. The term "high-temperature resilience" signifies, loosely, the ability of a cell to resist such deterioration, retaining as much as possible of its initial charge/discharge capacity during operation or during storage in the fully charged condition at high temperature. For the purposes of the present development, a temperature is considered to be high if it equals or exceeds the upper limit (typically, 30 C) of the operating-temperature range for which the cells in question are generally designed.

  4. Electrolytes for Low-Temperature Operation of Li-CFx Cells

    Science.gov (United States)

    Smart, Marshall C.; Whitacre, Jay F.; Bugga, Ratnakumar V.; Prakash, G. K. Surya; Bhalla, Pooja; Smith, Kiah

    2009-01-01

    A report describes a study of electrolyte compositions selected as candidates for improving the low-temperature performances of primary electrochemical cells that contain lithium anodes and fluorinated carbonaceous (CFx) cathodes. This study complements the developments reported in Additive for Low-Temperature Operation of Li-(CF)n Cells (NPO- 43579) and Li/CFx Cells Optimized for Low-Temperature Operation (NPO- 43585), which appear elsewhere in this issue of NASA Tech Briefs. Similar to lithium-based electrolytes described in several previous NASA Tech Briefs articles, each of these electrolytes consisted of a lithium salt dissolved in a nonaqueous solvent mixture. Each such mixture consisted of two or more of the following ingredients: propylene carbonate (PC); 1,2-dimethoxyethane (DME); trifluoropropylene carbonate; bis(2,2,2-trifluoroethyl) ether; diethyl carbonate; dimethyl carbonate; and ethyl methyl carbonate. The report describes the physical and chemical principles underlying the selection of the compositions (which were not optimized) and presents results of preliminary tests made to determine effects of the compositions upon the low-temperature capabilities of Li-CFx cells, relative to a baseline composition of LiBF4 at a concentration of 1.0 M in a solvent comprising equal volume parts of PC and DME.

  5. Perfluoro anion based binary and ternary ionic liquids as electrolytes for dye-sensitized solar cells

    Science.gov (United States)

    Lin, Hsi-Hsin; Peng, Jia-De; Suryanarayanan, V.; Velayutham, D.; Ho, Kuo-Chuan

    2016-04-01

    In this work, eight new ionic liquids (ILs) based on triethylammonium (TEA) or n-methylpiperidinium (NMP) cations and perfluoro carboxylate (PFC) anions having different carbon chain lengths are synthesized and their physico-chemical properties such as density, decomposition temperature, viscosity and conductivity are determined. Photovoltaic characteristics of dye-sensitized solar cells (DSSCs) with binary ionic liquids electrolytes, containing the mixture of the synthesized ILs and 1-methyl-3-propyl imidazolium iodide (PMII) (v/v = 35/65), are evaluated. Among the different ILs, solar cells containing NMP based ILs show higher VOC than that of TEA, whereas, higher JSC is noted for the DSSCs incorporated with the latter when compared to the former. Further, the photo-current of the DSSCs decreases with the increase of the carbon chain length of perfluoro carboxylate anionic group of ILs. The cell performance of the DSSC containing ternary ionic liquids-based electrolytes compose of NMP-2C/TEA-2C/PMII (v/v/v = 28/7/65) exhibits a JSC of 12.99 mA cm-2, a VOC of 639.0 mV, a FF of 0.72, and a cell efficiency of 6.01%. The extraordinary durability of the DSSC containing the above combination of electrolytes stored in dark at 50 °C is proved to be unfailing up to 1200 h.

  6. Influence of electrolyte co-additives on the performance of dye-sensitized solar cells

    Science.gov (United States)

    Stergiopoulos, Thomas; Rozi, Evangelia; Karagianni, Chaido-Stefania; Falaras, Polycarpos

    2011-12-01

    The presence of specific chemical additives in the redox electrolyte results in an efficient increase of the photovoltaic performance of dye-sensitized solar cells (DSCs). The most effective additives are 4- tert-butylpyridine (TBP), N-methylbenzimidazole (NMBI) and guanidinium thiocyanate (GuNCS) that are adsorbed onto the photoelectrode/electrolyte interface, thus shifting the semiconductor's conduction band edge and preventing recombination with triiodides. In a comparative work, we investigated in detail the action of TBP and NMBI additives in ionic liquid-based redox electrolytes with varying iodine concentrations, in order to extract the optimum additive/I2 ratio for each system. Different optimum additive/I2 ratios were determined for TBP and NMBI, despite the fact that both generally work in a similar way. Further addition of GuNCS in the optimized electrolytic media causes significant synergistic effects, the action of GuNCS being strongly influenced by the nature of the corresponding co-additive. Under the best operation conditions, power conversion efficiencies as high as 8% were obtained.

  7. Performance Degradation of Dye-Sensitized Solar Cells Induced by Electrolytes

    Directory of Open Access Journals (Sweden)

    Ru-Yuan Yang

    2012-01-01

    Full Text Available We investigated the change of the electric characteristics in dye-sensitized solar cell (DSSC when the electrolyte has been injected and measured initially and lately for a period of time. It was found that the short-circuit current density decreased from 9.799 mA/cm2 to 7.056 mA/cm2 and the fill factor increased from 0.406 to 0.559 when the cell had stood for an hour, while the open-circuit photovoltage did not change due to fixed difference between the Fermi level of TiO2 and the oxidation-reduction potential of electrolyte. The results can be explained by using the variation of the series resistance in the equivalent circuit of the DSSC.

  8. Preparation and characterization of radiation-grafted polymer electrolyte membrane for applications in fuel cells

    International Nuclear Information System (INIS)

    Polymer electrolyte membrane (PEM) is a key material that strongly affects the cell performance, cost and application prospect of the PEM fuel cell. The membrane acts as a separator to prevent mixing of the reactant gases and as an electrolyte for proton transportation. Radiation-grafted PEM has a special chemical structure, composing of fluorinated main chains and sulfonated side chains. The main chain acts as a stable backbone that gives the necessary strength, dimensional stability and gas barrier while the side chain gives the ability of proton transportation. In our study, the suitability of some base films, monomers and crosslinkers, as well as the preparation processes have been investigated in detail in order to develop a high performance radiation-grafted PEM. (authors)

  9. Development and calibration of an electrolytic cell for ion determination in a soil solution

    Directory of Open Access Journals (Sweden)

    Omar Cleo Neves Pereira

    2015-05-01

    Full Text Available An electrolytic cell was developed to monitor soil modifications after crop fertigation with wastewaters from agroindustrial plants. The device was first calibrated with different levels of potassium chloride dissolved in aqueous solutions at various temperatures. Nernst´s model was used to fit the voltage indicated from the electrolytic cell versus the ionic activity of the potassium from the aqueous solutions of electrical conductivity and known ionic concentrations and the diluted wastewater samples. The equipment accurately indicated the tensions after appropriated correction of the electrical current and the temperature. The device estimated with accuracy the ionic coefficient of activity, the concentration of the potassium chloride and the concentration of the ion K dissolved in the agro-industrial wastewater.

  10. Catalytic and electrocatalytic oxidation of carbon monoxide on a Fe electrode in a solid electrolyte cell

    International Nuclear Information System (INIS)

    The catalytic oxidation of carbon monoxide on Fe catalyst was studied at 300-500C and atmospheric total pressure. The reaction was studied under both open- and closed-circuit operation in an yttria-stabilized zirconia solid electrolyte cell. The technique of Solid Electrolyte Potentiometry (SEP) was used to monitor the thermodynamic activity of oxygen adsorbed on the Fe electrode under open circuit. Kinetic and potentiometric measurements were combined in order to elucidate the reaction mechanism. The results are in agreement with a Langmuir-Hinselwood type of adsorption-reaction with two different adsorption sites for carbon monoxide and oxygen. Under closed circuit, the effect of electrochemical oxygen 'pumping' to the catalyst was examined. The operation of the cell was almost Faradaic as the rate enhancement factor (λ) values measured were close to unity

  11. Effective solid electrolyte based on benzothiazolium for dye-sensitized solar cells.

    Science.gov (United States)

    Han, Lu; Wang, Ye Feng; Zeng, Jing Hui

    2014-12-24

    Thiaozole/benzothiaozole-based dicationic conductors were synthesized and applied as solid-state electrolyte in dye-sensitized solar cells (DSSCs). X-ray diffraction, scanning electron microscopy, thermal gravimetric analysis, steady-state voltammogram, photocurrent intensity-photovoltage test, and electrochemical impedance spectroscopy are used to characterize the materials and the mechanism of the cell performance. Compared to the traditional monocationic crystals, the dicationic crystals have a larger size and can provide more opportunities to fine-tune their physical/chemical properties. As a consequence, this solid-state electrolyte-based DSSC achieved photoelectric conversion efficiency of 7.90% under full air-mass (AM 1.5) sunlight (100 mW·cm(-2)). PMID:25469936

  12. Electrochemical behavior of CrN coating for polymer electrolyte membrane fuel cell

    International Nuclear Information System (INIS)

    CrN films on a bipolar plate in polymer electrolyte membrane fuel cells have several advantages owing to their excellent corrosion resistance and mechanical properties. Three CrN samples deposited at various radio frequency (RF) powers by RF magnetron sputtering were evaluated under potentiodynamic, potentiostatic and electrochemical impedance spectroscopy conditions. The electrochemical impedance spectroscopy data were monitored for 168 h in a corrosive environment at 70 0C to determine the coating performance at +600 mVSCE under simulated cathodic conditions in a polymer electrolyte membrane fuel cell. The electrochemical behavior of the coatings increased with decreasing RF power. CrN films on the AISI 316 stainless steel substrate showed high protective efficiency and charge transfer resistance, i.e. increasing corrosion resistance with decreasing RF power. X-ray diffraction confirmed the formation of a CrN(200) preferred orientation at low RF power.

  13. Polybenzimidazole and sulfonated polyhedral oligosilsesquioxane composite membranes for high temperature polymer electrolyte membrane fuel cells

    International Nuclear Information System (INIS)

    Composite membranes based on poly(2,2′(m-phenylene)-5,5′bibenzimidazole) (PBI) and sulfonated polyhedral oligosilsesquioxane (S-POSS) with S-POSS contents of 5 and 10 wt.% were prepared by solution casting as base materials for high temperature polymer electrolyte membrane fuel cells. With membranes based on pure PBI as a reference point, the composite membranes were characterized with respect to spectroscopic and physicochemical properties. After doping with phosphoric acid, the composite membranes showed considerably improved ex situ proton conductivity under anhydrous as well as under fully humidified conditions in the 120-180 °C temperature range. The conductivity improvements were also confirmed by in situ fuel cell tests at 160 °C and further supported by the electrochemical impedance spectroscopy data based on the operating membrane electrode assemblies, demonstrating the technical feasibility of the novel electrolyte materials

  14. Direct dimethyl ether high temperature polymer electrolyte membrane fuel cells

    DEFF Research Database (Denmark)

    Vassiliev, Anton; Jensen, Jens Oluf; Li, Qingfeng;

    A high temperature polybenzimidazole (PBI) polymer fuel cell was fed with dimethyl ether (DME) and water vapour mixture on the anode at ambient pressure with air as oxidant. A peak power density of 79 mW/cm2 was achieved at 200°C. A conventional polymer based direct DME fuel cell is liquid fed and...... suffers from low DME solubility in water. When the DME - water mixture is fed as vapour miscibility is no longer a problem. The increased temperature is more beneficial for the kinetics of the direct oxidation of DME than of methanol. The Open Circuit Voltage (OCV) with DME operation was 50 to 100 m...

  15. Estimation of localized current anomalies in polymer electrolyte fuel cells from magnetic flux density measurements

    Science.gov (United States)

    Nara, Takaaki; Koike, Masanori; Ando, Shigeru; Gotoh, Yuji; Izumi, Masaaki

    2016-05-01

    In this paper, we propose novel inversion methods to estimate defects or localized current anomalies in membrane electrode assemblies (MEAs) in polymer electrolyte fuel cells (PEFCs). One method is an imaging approach with L1-norm regularization that is suitable for estimation of focal anomalies compared to Tikhonov regularization. The second is a complex analysis based method in which multiple pointwise current anomalies can be identified directly and algebraically from the measured magnetic flux density.

  16. Study and development of a hydrogen/oxygen fuel cell in solid polymer electrolyte technology

    Energy Technology Data Exchange (ETDEWEB)

    Mosdale, R.

    1992-10-29

    The hydrogen/oxygen fuel cell appears today as the best candidate to the replacing of the internal combustion engine for automobile traction. This system uses the non explosive electrochemical recombination of hydrogen and oxygen. It is a clean generator whom only reactive product is water. This thesis shows a theoretical study of this system, the synthesis of different kinds of used electrodes and finally an analysis of water movements in polymer electrolyte by different original technologies. 70 refs., 73 figs., 15 tabs.

  17. Surface Analytical Methods for the Development of Electrochemical Components of Polymer Electrolyte Fuel Cells

    OpenAIRE

    Biswas, Indro; Gazdzicki, Pawel; Schulze, Mathias

    2013-01-01

    The transition from fossil to renewable energies implies significant changes in the energy system regarding the distribution, storage and energy conversion due to the intrinsic natural fluctuations of renewable power sources. Polymer electrolyte fuel cells (PEFC) are highly efficient electrochemical energy converters that may be implemented in a wide range of power and dynamics. Their high gravimetric energy density makes them attractive for many applications, especially for mobile purpos...

  18. Characterization of pore network structure in catalyst layers of polymer electrolyte fuel cells

    OpenAIRE

    El Hannach, Mohamed; Soboleva, Tatyana; Malek, Kourosh; Franco, Alejandro A.; Prat, Marc; Pauchet, Joël; Holdcroft, Steven

    2014-01-01

    International audience We model and validate the effect of ionomer content and Pt nanoparticles on nanoporous structure of catalyst layers in polymer electrolyte fuel cells. By employing Pore network modeling technique and analytical solutions, we analyze and reproduce experimental N2-adsorption isotherms of carbon, Pt/ carbon and catalyst layers with various ionomer contents. The porous catalyst layer structures comprise of Ketjen Black carbon, Pt and Nafion ionomer. The experimental pore...

  19. New polymer electrolytes for low temperature fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Sundholm, F.; Elomaa, M.; Ennari, J.; Hietala, S.; Paronen, M. [Univ. of Helsinki (Finland). Lab. of Polymer Chemistry

    1998-12-31

    Proton conducting polymer membranes for demanding applications, such as low temperature fuel cells, have been synthesised and characterised. Pre-irradiation methods are used to introduce sulfonic acid groups, directly or using polystyrene grafting, in stable, preformed polymer films. The membranes produced in this work show promise for the development of cost-effective, highly conducting membranes. (orig.)

  20. 300 W polymer electrolyte fuel cell generators for educational purposes

    Energy Technology Data Exchange (ETDEWEB)

    Tsukada, A.; Buechi, F.N.; Scherer, G.G.; Haas, O. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Popelis, I. [Fachhochschule Solothurn Nordwestschweiz (Switzerland)

    1999-08-01

    A 300 W fuel cell power pack has been developed for educational purposes in close collaboration with the Fachhochschule Solothurn Nordwestschweiz. The project was initiated and financed by the Swiss Federal Office of Energy. The outlay and the performance of the power pack are described. (author) 3 figs.

  1. Surface engineering of nanoporous substrate for solid oxide fuel cells with atomic layer-deposited electrolyte

    Directory of Open Access Journals (Sweden)

    Sanghoon Ji

    2015-08-01

    Full Text Available Solid oxide fuel cells with atomic layer-deposited thin film electrolytes supported on anodic aluminum oxide (AAO are electrochemically characterized with varying thickness of bottom electrode catalyst (BEC; BECs which are 0.5 and 4 times thicker than the size of AAO pores are tested. The thicker BEC ensures far more active mass transport on the BEC side and resultantly the thicker BEC cell generates ≈11 times higher peak power density than the thinner BEC cell at 500 °C.

  2. Poly (vinyl alcohol) hydrogel membrane as electrolyte for direct borohydride fuel cells

    Indian Academy of Sciences (India)

    N A Choudhury; S K Prashant; S Pitchumani; P Sridhar; A K Shukla

    2009-09-01

    A direct borohydride fuel cell (DBFC) employing a poly (vinyl alcohol) hydrogel membrane electrolyte (PHME) is reported. The DBFC employs an AB5 Misch metal alloy as anode and a goldplated stainless steel mesh as cathode in conjunction with aqueous alkaline solution of sodium borohydride as fuel and aqueous acidified solution of hydrogen peroxide as oxidant. Room temperature performances of the PHME-based DBFC in respect of peak power outputs; ex-situ cross-over of oxidant, fuel, anolyte and catholyte across the membrane electrolytes; utilization efficiencies of fuel and oxidant, as also cell performance durability are compared with a similar DBFC employing a Nafion®-117 membrane electrolyte (NME). Peak power densities of ∼30 and ∼40 mW cm-2 are observed for the DBFCs with PHME and NME, respectively. The crossover of NaBH4 across both the membranes has been found to be very low. The utilization efficiencies of NaBH4 and H2O2 are found to be ∼24 and ∼59%, respectively for the PHME-based DBFC; ∼18 and ∼62%, respectively for the NME-based DBFC. The PHME and NME-based DBFCs exhibit operational cell potentials of ∼ 1.2 and ∼ 1.4 V, respectively at a load current density of 10 mA cm-2 for ∼100 h.

  3. STABLE HIGH CONDUCTIVITY BILAYERED ELECTROLYTES FOR LOW TEMPERATURE SOLID OXIDE FUEL CELLS

    Energy Technology Data Exchange (ETDEWEB)

    Eric D. Wachsman; Keith L. Duncan

    2002-09-30

    A bilayer electrolyte consisting of acceptor-doped ceria (on the fuel/reducing side) and cubic-stabilized bismuth oxide (on the oxidizing side) was developed. The bilayer electrolyte that was developed showed significant improvement in open-circuit potential versus a typical ceria based SOFC. Moreover, the OCP of the bilayer cells increased as the thickness of the bismuth oxide layer increased relative to the ceria layer. Thereby, verifying the bilayer concept. Although, because of the absence of a suitable cathode (a problem we are still working assiduously to solve), we were unable to obtain power density curves, our modeling work predicts a reduction in electrolyte area specific resistance of two orders of magnitude over cubic-stabilized zirconia and projects a maximum power density of 9 W/m{sup 2} at 800 C and 0.09 W/m{sup 2} at 500 C. Towards the development of the bilayer electrolyte other significant strides were made. Among these were, first, the development of a, bismuth oxide based, oxide ion conductor with the highest conductivity (0.56 S/cm at 800 C and 0.043 S/cm at 500 C) known to date. Second, a physical model of the defect transport mechanisms and the driving forces for the ordering phenomena in bismuth oxide and other fluorite systems was developed. Third, a model for point defect transport in oxide mixed ionic-electronic conductors was developed, without the typical assumption of a uniform distribution of ions and including the effect of variable loads on the transport properties of an SOFC (with either a single or bilayer electrolyte).

  4. 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

  5. Steady State Multiplicity in a Polymer Electrolyte Membrane Fuel Cell

    OpenAIRE

    Chia, Ee-Sunn J.; Benziger, Jay B.; Kevrekidis, Ioannis G.

    2003-01-01

    A simplified differential reactor model that embodies the essential physics controlling PEM fuel cell (PEM-FC) dynamics is presented. A remarkable analogy exists between water management in the differential PEM-FC and energy balance in the classical exothermic stirred tank reactor. Water, the reaction product in the PEM-FC autocatalytically accelerates the reaction rate by enhancing proton transport through the PEM. Established analyses of heat autocatalyticity in a CSTR are modified to prese...

  6. Modeling Water Management in Polymer-Electrolyte Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Department of Chemical Engineering, University of California, Berkeley; Weber, Adam; Weber, Adam Z.; Balliet, Ryan; Gunterman, Haluna P.; Newman, John

    2007-09-07

    Fuel cells may become the energy-delivery devices of the 21st century with realization of a carbon-neutral energy economy. Although there are many types of fuel cells, polymerelectrolyte fuel cells (PEFCs) are receiving the most attention for automotive and small stationary applications. In a PEFC, hydrogen and oxygen are combined electrochemically to produce water, electricity, and waste heat. During the operation of a PEFC, many interrelated and complex phenomena occur. These processes include mass and heat transfer, electrochemical reactions, and ionic and electronic transport. Most of these processes occur in the through-plane direction in what we term the PEFC sandwich as shown in Figure 1. This sandwich comprises multiple layers including diffusion media that can be composite structures containing a macroporous gas-diffusion layer (GDL) and microporous layer (MPL), catalyst layers (CLs), flow fields or bipolar plates, and a membrane. During operation fuel is fed into the anode flow field, moves through the diffusion medium, and reacts electrochemically at the anode CL to form hydrogen ions and electrons. The oxidant, usually oxygen in air, is fed into the cathode flow field, moves through the diffusion medium, and is electrochemically reduced at the cathode CL by combination with the generated protons and electrons. The water, either liquid or vapor, produced by the reduction of oxygen at the cathode exits the PEFC through either the cathode or anode flow field. The electrons generated at the anode pass through an external circuit and may be used to perform work before they are consumed at the cathode. The performance of a PEFC is most often reported in the form of a polarization curve, as shown in Figure 2. Roughly speaking, the polarization curve can be broken down into various regions. First, it should be noted that the equilibrium potential differs from the open-circuit voltage due mainly to hydrogen crossover through the membrane (i.e., a mixed potential

  7. Fuel-Cell Electrolytes Based on Organosilica Hybrid Proton Conductors

    Science.gov (United States)

    Narayan, Sri R.; Yen, Shiao-Pin S.

    2008-01-01

    A new membrane composite material that combines an organosilica proton conductor with perfluorinated Nafion material to achieve good proton conductivity and high-temperature performance for membranes used for fuel cells in stationary, transportation, and portable applications has been developed. To achieve high proton conductivities of the order of 10(exp -1)S/cm over a wide range of temperatures, a composite membrane based on a new class of mesoporous, proton-conducting, hydrogen-bonded organosilica, used with Nafion, will allow for water retention and high proton conductivity over a wider range of temperatures than currently offered by Nafion alone. At the time of this reporting, this innovation is at the concept level. Some of the materials and processes investigated have shown good proton conductivity, but membranes have not yet been prepared and demonstrated.

  8. Improved power conversion efficiency of dye-sensitized solar cells using side chain liquid crystal polymer embedded in polymer electrolytes

    International Nuclear Information System (INIS)

    Side chain liquid crystal polymer (SCLCP) embedded in poly(vinylidenefluoride-co-hexafluoropropylene) (PVdF-co-HFP)-based polymer electrolytes (PVdF-co-HFP:side chain liquid crystal polymer (SCLCP)) was prepared for dye-sensitized solar cell (DSSC) application. The polymer electrolytes contained tetrabutylammonium iodide (TBAI), iodine (I2), and 8 wt% PVdF-co-HFP in acetonitrile. DSSCs comprised of PVdF-co-HFP:SCLCP-based polymer electrolytes displayed enhanced redox couple reduction and reduced charge recombination in comparison to those of the conventional PVdF-co-HFP-based polymer electrolyte. The significantly increased short-circuit current density (Jsc, 10.75 mA cm−2) of the DSSCs with PVdF-co-HFP:SCLCP-based polymer electrolytes afforded a high power conversion efficiency (PCE) of 5.32% and a fill factor (FF) of 0.64 under standard light intensity of 100 mW cm−2 irradiation of AM 1.5 sunlight. - Highlights: • We developed the liquid crystal polymer embedded on polymer electrolyte for DSSCs. • We fabricated the highly efficient DSSCs using polymer electrolyte. • The best PCE achieved for P1 is 5.32% using polymer electrolyte

  9. Quasi-solid-state dye-sensitized solar cells with cyanoacrylate as electrolyte matrix

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Shengli [Linz Institute for Organic Solar Cells (LIOS), Johannes Kepler University Linz, Altenbergerstr. 69, A-4040 Linz (Austria); Institute for Organic Solar Energy Opto-Electronic Materials, College of Biological and Chemical Engineering, Zhejiang University of Science and Technology, Hangzhou 310012 (China); Koeppe, Robert; Guenes, Serap; Sariciftci, Niyazi Serdar [Linz Institute for Organic Solar Cells (LIOS), Johannes Kepler University Linz, Altenbergerstr. 69, A-4040 Linz (Austria)

    2007-07-23

    A quasi-solid-state dye-sensitized solar cells (DSSCs) employing a commercial glue (''SuperGlue {sup registered} '') as electrolyte matrix was fabricated. The cyano groups of the cyanoacrylate can form a supramolecular complex with tetrapropylammonium cations. This immobilizes the cations and therefore might lead to a favored anionic charge transport necessary for a good performance of the iodide/triiodide electrolytic conductor. Obtaining energy conversion efficiencies of more than 4% under 100 mW/cm{sup 2} of simulated A.M. 1.5 illumination, the cyanoacrylate quasi-solid-state electrolyte is an ordinary and low-cost compound which has fast drying property and offers significant advantages in the fabrication of solar cells and modules as it is in itself is a very good laminating agent. The influences of different porous layer thicknesses of titanium oxide and various kinds of cations on DSSC performance and long-term stability are presented. (author)

  10. Performance analysis of a direct carbon fuel cell with molten carbonate electrolyte

    International Nuclear Information System (INIS)

    The model of a packed bed anode DCFC (direct carbon fuel cell) with molten carbonate as an electrolyte and graphite as a fuel is established to globally evaluate its performance. Thermodynamic-electrochemical analyses on the performance of the DCFC are implemented, in which the activation overpotential, ohmic overpotential, and concentration overpotential are taken as the main sources of voltage losses. The analytical expressions for the cell voltage, power output, efficiency, and entropy production rate are derived, from which the general performance characteristics are discussed in detail. At the anode, the ohmic overpotential in each slab resulting from the carbon phase is found to be about three orders of magnitude larger than that resulting from the electrolyte phase. The radius of the real contact area between two neighboring graphite particles decreases at an accelerating rate as one goes up in the bed, and the corresponding constriction resistance will increase at an accelerating rate. The decrease in the operating current density and anode dimension and the increase in the operating temperature will lessen the overall ohmic overpotential. The effects of the operating current density, operating temperature and anode dimension on the performance are discussed, and the optimum criteria for some important performance parameters are determined. - Highlights: • An irreversible model of a DCFC with molten carbonate electrolyte is proposed. • Main irreversible losses in the DCFC are analytically characterized. • General performance characteristics of the DCFC are revealed. • Optimum operation regions of some performance parameters are determined

  11. Long-Term Degradation Testing of High-Temperature Electrolytic Cells

    Energy Technology Data Exchange (ETDEWEB)

    C.M. Stoots; J.E. O' Brien; J.S. Herring; G.K. Housley; D.G. Milobar; M.S. Sohal

    2009-08-01

    The Idaho National Laboratory (INL) has been researching the application of solid-oxide electrolysis cell for large-scale hydrogen production from steam over a temperature range of 800 to 900ºC. The INL has been testing various solid oxide cell designs to characterize their electrolytic performance operating in the electrolysis mode for hydrogen production. Some results presented in this report were obtained from cells, with an active area of 16 cm2 per cell. The electrolysis cells are electrode-supported, with ~10 µm thick yttria-stabilized zirconia (YSZ) electrolytes, ~1400 µm thick nickel-YSZ steam-hydrogen electrodes, and manganite (LSM) air-oxygen electrodes. The experiments were performed over a range of steam inlet mole fractions (0.1 to 0.6), gas flow rates, and current densities (0 to 0.6 A/cm2). Steam consumption rates associated with electrolysis were measured directly using inlet and outlet dewpoint instrumentation. On a molar basis, the steam consumption rate is equal to the hydrogen production rate. Cell performance was evaluated by performing DC potential sweeps at 800, 850, and 900°C. The voltage-current characteristics are presented, along with values of area-specific resistance as a function of current density. Long-term cell performance is also assessed to evaluate cell degradation. Details of the custom single-cell test apparatus developed for these experiments are also presented. NASA, in conjunction with the University of Toledo, has developed a new cell concept with the goals of reduced weight and high power density. This report presents results of the INL's testing of this new solid oxide cell design as an electrolyzer. Gas composition, operating voltage, and other parameters were varied during testing. Results to date show the NASA cell to be a promising design for both high power-to-weight fuel cell and electrolyzer applications.

  12. Interpretation of the current-voltage characteristics of polymer electrolyte fuel cells by impedance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Andreaus, B.; McEvoy, A.J.; Scherer, G.

    2003-03-01

    We applied electrochemical impedance spectroscopy (EIS) to elucidate the origins of the voltage losses of a H{sub 2} /O{sub 2} polymer electrolyte fuel cell (PEFC) as a function of current density. The results indicate that the commercial electrodes utilized in these experiments suffer from a substantial loss in active catalyst sur-face already at relatively low current densities. The drying out of the electrolyte in the membrane adjacent to the anode as well as in the anode active layer results in an additional voltage loss at high current densities. Therefore, the purely structural aspects of a robust triple phase boundary sustaining harsh conditions under load is at least equally important as the proper choice of catalyst for a high performance PEFC-electrode. (author)

  13. Neutronic measurements on electrolytic cells with deuterated palladium in a submarine environment

    International Nuclear Information System (INIS)

    Using a high efficiency system for the neutron thermal detection and a pulsed electrolytic current procedure, measurements were made on cells containing Pd cathodes and electrolytes at a D2O and H2O base. The peculiarity of these experiments is that they were carried out on board of the A.R.A. Santa Cruz submarine, at a depth of 50m under sea level, attaining ultra deep-down conditions in the measurements, corresponding to a reduction in a factor = 50 in relation to lab conditions. The mean level of the signal -obtained from counting combination of deuterated cathodes- results to be separated from the deep-down level by four standard deviations. (Author)

  14. Modeling and Simulation for Fuel Cell Polymer Electrolyte Membrane

    Directory of Open Access Journals (Sweden)

    Takahiro Hayashi

    2013-01-01

    Full Text Available We have established methods to evaluate key properties that are needed to commercialize polyelectrolyte membranes for fuel cell electric vehicles such as water diffusion, gas permeability, and mechanical strength. These methods are based on coarse-graining models. For calculating water diffusion and gas permeability through the membranes, the dissipative particle dynamics–Monte Carlo approach was applied, while mechanical strength of the hydrated membrane was simulated by coarse-grained molecular dynamics. As a result of our systematic search and analysis, we can now grasp the direction necessary to improve water diffusion, gas permeability, and mechanical strength. For water diffusion, a map that reveals the relationship between many kinds of molecular structures and diffusion constants was obtained, in which the direction to enhance the diffusivity by improving membrane structure can be clearly seen. In order to achieve high mechanical strength, the molecular structure should be such that the hydrated membrane contains narrow water channels, but these might decrease the proton conductivity. Therefore, an optimal design of the polymer structure is needed, and the developed models reviewed here make it possible to optimize these molecular structures.

  15. Characterization of Titanium Phosphate as Electrolytes in Fuel Cells

    Science.gov (United States)

    Tran, A. T. T.; Duke, M. C.; Gray, P. G.; Diniz da Costa, J. C.

    Titanium phosphate is currently a promising material for proton exchange membrane fuel cells applications (PEMFC) allowing for operation at high temperature conditions. In this work, titanium phosphate was synthesized from tetra iso-propoxide (TTIP) and orthophosphoric acid (H3PO4) in different ratios by a sol gel method. High BET surface areas of 271 m2.g-1 were obtained for equimolar Ti:P samples whilst reduced surface areas were observed by varying the molar ratio either way. Highest proton conductivity of 5.4×10-2 S.cm-1 was measured at 20°C and 93% relative humidity (RH). However, no correlation was observed between surface area and proton conductivity. High proton conductivity was directly attributed to hydrogen bonding in P-OH groups and the water molecules retained in the sample structure. The proton conductivity increased with relative humidity, indicating that the Grotthuss mechanism governed proton transport. Further, sample Ti/P with 1:9 molar ratio showed proton conductivity in the order of 10-1 S.cm-1 (5% RH) and ~1.6×10-2 S.cm-1 (anhydrous condition) at 200°C. These proton conductivities were mainly attributed to excess acid locked into the functionalized TiP structure, thus forming ionisable protons.

  16. Review on development of electrolytes for dye-sensitized solar cells

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Since the prototype of a dye-sensitized solar cell(DSSC)was reported in 1991 by M. Gratzel,it has aroused intensive interest over the past decade due to its low cost and simple preparation procedure.The typical cell consists of a dye-coated mesoporous nanocrystalline TiO_2 film sandwiched between two transparent electroldes.A liquid electrolyte,traditionally containing the trioidide/iodide redox couple,fills the pores of the mesoporous nanocrystalline TiO_2 film and contacts the nanoparticles.Photoexcite...

  17. Identification of liquid water constraints in micro polymer electrolyte fuel cells without gas diffusion layers

    International Nuclear Information System (INIS)

    A simplified, miniaturized polymer electrolyte fuel cell without gas diffusion layers was investigated under operation by neutron radiography. By visualizing liquid water, it was possible to identify limiting effects, which are directly related to the simplified construction principle. Depending on the operation conditions, undesired water accumulation either in particular micro-channels or on the cathode catalyst layer as well as drying of the anode catalyst layer was observed. As a consequence, the design of a fuel cell without gas diffusion layers must take into account these limitations visualized by neutron radiography.

  18. Range Extender Vehicle Concept Based on High Temperature Polymer Electrolyte Membrane Fuel Cell

    OpenAIRE

    Dickinson, Dave; Nasri, Mounir

    2014-01-01

    Battery electric vehicles that would be suitable for urban traffic as well as for longer distances will be equipped with a range extender (REX). In this range extender vehicle concept, the powertrain is driven mainly by the high performance li-ion battery added by a HT-PEFC (Polymer Electrolyte Membrane Fuel Cell). The on-board fuel cell range extender serves as an additional energy source, which charges the high performance battery during the trip especially in a long distance trip. O...

  19. Water removal studies on high power hydrogen-oxygen fuel cells with alkaline electrolytes

    Science.gov (United States)

    Kordesch, K.; Oliveira, J. C. T.; Gruber, Ch.; Winkler, G.

    1989-08-01

    Research in verification of bipolar fuel cell design, containing mass-produceable all-carbon electrodes which can be used in alkaline or acidic cells with liquid or immobilized (matrix) electrolytes, is described. Spin-offs from the research related to the Hermes manned spaceplane could be useful for applications on Earth. Peak-power plants, electric vehicles and storage devices used in combination with renewable energy sources could all benefit from the research. A subsequent investigation of water transpiration properties of carbon electrodes is described.

  20. Performance Degradation of Dye-Sensitized Solar Cells Induced by Electrolytes

    OpenAIRE

    Ru-Yuan Yang; Huang-Yu Chen; Fu-Der Lai

    2012-01-01

    We investigated the change of the electric characteristics in dye-sensitized solar cell (DSSC) when the electrolyte has been injected and measured initially and lately for a period of time. It was found that the short-circuit current density decreased from 9.799 mA/cm2 to 7.056 mA/cm2 and the fill factor increased from 0.406 to 0.559 when the cell had stood for an hour, while the open-circuit photovoltage did not change due to fixed difference between the Fermi level of TiO2 and the oxidation...

  1. Elucidating through-plane liquid water profile in a polymer electrolyte membrane fuel cell.

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yun (University of California, Irvine, CA); Chen, Ken Shuang

    2010-10-01

    In this paper, a numerical model incorporating micro-porous layers (MPLs) is presented for simulating water transport within the gas diffusion layers (GDLs) and MPLs as well as across their interfaces in a polymer electrolyte membrane (PEM) fuel cell. One-dimensional analysis is conducted to investigate the impacts of MPL and GDL properties on the liquid-water profile across the anode GDL-MPL and cathode MPL-GDL regions. Furthermore, two-dimensional numerical simulations that take MPLs into account are also carried out to elucidate liquid water transport, particularly through-plane liquid-water profile in a PEM fuel cell. Results from case studies are presented.

  2. Tritiated water processing using liquid phase catalytic exchange and solid oxide electrolyte cell

    International Nuclear Information System (INIS)

    Liquid phase catalytic exchange (LPCE) is an effective method for enrichment and removal of tritium from tritiated water. Combined electrolysis catalytic exchange (CECE) process is an attractive application of a LPCE column. We proposed a new process that improves the CECE process. Using a solid oxide electrolyte (SOE) cell for electrolysis makes the CECE process more energy efficient and eliminates other disadvantages such as large tritium inventory and extremely slow system response. When the cell is used for recombination, the system becomes even more simple, efficiently, reliable and safe. 21 refs., 9 figs

  3. Fabrication of thin yttria-stabilized-zirconia dense electrolyte layers by inkjet printing for high performing solid oxide fuel cells

    DEFF Research Database (Denmark)

    Esposito, Vincenzo; Gadea, Christophe; Hjelm, Johan;

    2015-01-01

    In this work, we present how a low-cost HP Deskjet 1000 inkjet printer was used to fabricate a 1.2 mm thin, dense and gas tight 16 cm2 solid oxide fuel cells (SOFC) electrolyte. The electrolyte was printed using an ink made of highly diluted (<4 vol.%) nanometric yttria stabilized zirconia (YSZ) ...... printing pass. Together with an optimized sintering procedure this resulted in good adhesion and densification of the electrolyte. The SOFC exhibited a close-to-theoretical open circuit voltage and a remarkable peak power density above 1.5 W cm-2 at 800 °C....

  4. Demonstration of high efficiency intermediate-temperature solid oxide fuel cell based on lanthanum gallate electrolyte

    International Nuclear Information System (INIS)

    The Kansai Electric Power Co., Inc. (KEPCO) and Mitsubishi Materials Corporation (MMC) have been jointly developing intermediate-temperature solid oxide fuel cells (SOFCs). The operation temperatures between 600 and 800 oC were set as the target, which enable SOFC to use less expensive metallic separators for cell-stacking and to carry out internal reforming of hydrocarbon fuels. The electrolyte-supported planar-type cells were fabricated using highly conductive lanthanum gallate-based electrolyte, La(Sr)Ga(Mg,Co)O3-δ, Ni-(CeO2)1-x(SmO1.5) x cermet anode, and Sm(Sr)CoO3-δ cathode. The 1 kW-class power generation modules were fabricated using a seal-less stack of the cells and metallic separators. The 1 kW-class prototype power generation system with the module was developed with the high performance cell, which showed the thermally self-sustainability. The system included an SOFC module, a dc-ac inverter, a desulfurizer, and a heat recovery unit. It provided stable ac power output of 1 kW with the electrical efficiency of 45% LHV based on ac output by using city gas as a fuel, which was considered to be excellent for such a small power generation system. And the hot water of 90 oC was obtained using high temperature off-gas from SOFC

  5. A mathematical model of the solid-polymer-electrolyte fuel cell

    Science.gov (United States)

    Bernardi, Dawn M.; Verbrugge, Mark W.

    1992-09-01

    A mathematical model of the solid-polymer-electrolyte fuel cell is presented and applied to investigate factors that limit cell performance and elucidate the mechanism of species transport in the complex network of gas, liquid, and solid phases of the cell. Calculations of cell polarization behavior compare favorably with existing experimental data. For most practical electral thicknesses, model results indicate that the volume fraction of the cathode available for gas transport must exceed 20 percent in order to avoid unacceptably low cell-limiting current densities. It is shown that membrane dehydration can also pose limitations on operating current density. Circumvention of this problem by appropriate membrane and electrode design and efficient water-management schemes is discussed. It is found that for a broad range of practical current densities there are no external water requirements because the water produced at the cathode is sufficient to satisfy the water requirement of the membrane.

  6. A mathematical model of the solid-polymer-electrolyte fuel cell

    International Nuclear Information System (INIS)

    This paper presents a mathematical model of the solid-polymer-electrolyte fuel cell and apply it to (i) investigate factors that limit cell performance and (ii) elucidate the mechanism of species transport in the complex network of gas, liquid, and solid phases of the cell. Calculations of cell polarization behavior compare favorably with existing experimental data. For most practical electrode thicknesses, model results indicate that the volume fraction of the cathode available for gas transport must exceed 20% in order to avoid unacceptably low cell-limiting current densities. It is shown that membrane dehydration can also pose limitations on operating current density; circumvention of this problem by appropriate membrane and electrode design and efficient water-management schemes is discussed. The authors' model results indicate that for a broad range of practical current densities there are no external water requirements because the water produced at the cathode is enough to satisfy the water requirement of the membrane

  7. Optimizing the Manufacturing Method of Half-Cell Fuel Cell Based on Solid Electrolyte with Hydrogen Ion Conductivity

    Directory of Open Access Journals (Sweden)

    Naghmeh Mirab

    2012-01-01

    Full Text Available Barium cerate-based perovskite oxides are protonic conductor candidates for intermediate temperature solid oxide fuel cells due to their high ionic conductivity and good sinterability. The aim of the present study is to fabricate a half-cell single-cell includes substrate, anode and electrolyte layers. The exact composition of BaZr0.1Ce0.7Y0.2O3─δ (BZCY7 has been selected as a proton conducting electrolyte. The fabrication process of a dense electrolyte membrane on a NiO- BaZr0.1Ce0.7Y0.2O3─δ (NiO-BZCY7 anode substrate has been studied by a co-pressing process after co-firing at 1400ºC. BZCY7 powders were synthesized by solid-state reaction method after calcinations at 1150ºC. A single phase was obtained at this low temperature. The phase composition of the resulting specimens was investigated using X-ray diffraction (XRD analysis. Scanning electron microscope (SEM was used to evaluate the features of the synthesized powders and also the condition of connected layers in half-cell.

  8. A Tri-Layer Proton-Conducting Electrolyte for Chemically Stable Operation in Solid Oxide Fuel Cells

    KAUST Repository

    Bi, Lei

    2013-10-07

    Two BaZr0.7Pr0.1Y0.2O3-δ (BZPY) layers were used to sandwich a BaCe0.8Y0.2O3-δ (BCY) layer to produce a tri-layer electrolyte consisting of BZPY/BCY/BZPY. The BZPY layers significantly improved the chemical stability of the BCY electrolyte layer, which was not stable when tested alone, suggesting that the BZPY layer effectively protected the BCY layer from CO2 reaction, which is the major problem of BCY-based materials. A fuel cell with this sandwiched electrolyte supported on a Ni-based composite anode showed a reasonable cell performance, reaching 185 mW cm-2 at 700 oC, in spite of the relatively large electrolyte thickness (about 65 µm).

  9. Tungsten oxide in polymer electrolyte fuel cell electrodes-A thin-film model electrode study

    Energy Technology Data Exchange (ETDEWEB)

    Wickman, Bjoern, E-mail: bjorn.wickman@chalmers.s [Competence Centre for Catalysis, Department of Applied Physics, Chalmers University of Technology, SE-412 96 Goeteborg (Sweden); Wesselmark, Maria; Lagergren, Carina; Lindbergh, Goeran [Applied Electrochemistry, School of Chemical Science and Engineering, KTH, SE-100 44 Stockholm (Sweden)

    2011-10-30

    Highlights: > Platinum and tungsten oxide thin-film electrocatalysts. > Single cell fuel cell evaluation. > Hydrogen-tungsten bronze formation. > CO oxidation on platinum on tungsten oxide. - Abstract: Thin films of WO{sub x} and Pt on WO{sub x} were evaporated onto the microporous layer of a gas diffusion layer (GDL) and served as model electrodes in the polymer electrolyte fuel cell (PEFC) as well as in liquid electrolyte measurements. In order to study the effects of introducing WO{sub x} in PEFC electrodes, precise amounts of WO{sub x} (films ranging from 0 to 40 nm) with or without a top layer of Pt (3 nm) were prepared. The structure of the thin-film model electrodes was characterized by scanning electron microscopy and X-ray photoelectron spectroscopy prior to the electrochemical investigations. The electrodes were analyzed by cyclic voltammetry and the electrocatalytic activity for hydrogen oxidation reaction (HOR) and CO oxidation was examined. The impact of Nafion in the electrode structure was examined by comparing samples with and without Nafion solution sprayed onto the electrode. Fuel cell measurements showed an increased amount of hydrogen tungsten bronzes formed for increasing WO{sub x} thicknesses and that Pt affected the intercalation/deintercalation process, but not the total amount of bronzes. The oxidation of pre-adsorbed CO was shifted to lower potentials for WO{sub x} containing electrodes, suggesting that Pt-WO{sub x} is a more CO-tolerant catalyst than Pt. For the HOR, Pt on thicker films of WO{sub x} showed an increased limiting current, most likely originating from the increased electrochemically active surface area due to proton conductivity and hydrogen permeability in the WO{sub x} film. From measurements in liquid electrolyte it was seen that the system behaved very differently compared to the fuel cell measurements. This exemplifies the large differences between the liquid electrolyte and fuel cell systems. The thin-film model

  10. Low temperature preparation and fuel cell properties of rare earth doped barium cerate solid electrolytes

    Institute of Scientific and Technical Information of China (English)

    蒋凯; 何志奇; 孟建; 任玉芳; 苏锵

    1999-01-01

    The solid electrolytes, BaCe0.8 Ln0.2O2.9 (Ln: Gd, Sm, Eu), were prepared by the sol-gel method. XRD indicated that a pure orthorhombic phase was formed at 900℃. The synthesis temperature by the sol-gel method was about 600℃ lower than the high temperature solid phase reaction method, The electrical conductivity and impedance spectra were measured and the conduction mechanism was studied. The grain-boundary resistance of the solid electrolyte could be reduced or eliminated by the sol-gel method. The conductivity of BaCe0.8Gd0.2O2.9 is 7.87×10-2 S·cm-1 at 800℃. The open-circuit voltage of hydrogen-oxygen fuel cell using BaCe0.8 Gd0.2O2.9 as electrolyte was near to 1 V and its maximum power density was 30 mW·cm-2.

  11. High performance zirconia-bismuth oxide nanocomposite electrolytes for lower temperature solid oxide fuel cells

    Science.gov (United States)

    Joh, Dong Woo; Park, Jeong Hwa; Kim, Do Yeub; Yun, Byung-Hyun; Lee, Kang Taek

    2016-07-01

    We develop a novel nanocomposite electrolyte, consisting of yttria-stabilized zirconia (YSZ) and erbia-stabilized bismuth oxide (ESB). The 20 mol% ESB-incorporated YSZ composite (20ESB-YSZ) achieves the high density (>97%) at the low sintering temperature of 800 °C. The microstructural analysis of 20ESB-YSZ reveals the characteristic nanocomposite structure of the highly percolated ESB phase at the YSZ grain boundaries (a few ∼ nm thick). The ionic conductivity of 20ESB-YSZ is increased by 5 times compared to that of the conventional YSZ due to the fast oxygen ion transport along the ESB phase. Moreover, this high conductivity is maintained up to 580 h, indicating high stability of the ESB-YSZ nanocomposite. In addition, the oxygen reduction reaction at the composite electrolyte/cathode interface is effectively enhanced (∼70%) at the temperature below 650 °C, mainly due to the fast dissociative oxygen adsorption on the ESB surface as well as the rapid oxygen ion incorporation into the ESB lattice. Thus, we believe this ESB-YSZ nanocomposite is a promising electrolyte for high performance solid oxide fuel cells at reduced temperatures.

  12. Continuous treatments of estrogens through polymerization and regeneration of electrolytic cells

    International Nuclear Information System (INIS)

    Highlights: • Trace natural and synthetic estrogens were removed effectively by electrochemical oxidation process. • Removal efficiency of 93–98% was achieved through electrochemical polymerization. • Passivated electrodes were completely recovered to their initial conditions in continuous operation. • Removal performance could be controlled and enhanced by a mathematical model. - Abstract: This study proposes a novel electrolytic method for simultaneous removal of trace estrogens and regeneration of electrolytic cells for long-term wastewater treatment. Continuous treatments of estrogens estrone (E1), 17β-estradiol (E2) and 17α-ethinyl estradiol (EE2) were theoretically and experimentally studied using an electrolytic reactor equipped with a multi-packed granular glassy carbon electrode reactor. Experimental results demonstrated that E1, E2 and EE2 were effectively removed through electro-polymerization on the granular glassy carbon (and Pt/Ti) anode counter. Polymer formed during continuous treatment was quickly decomposed and electrodes were regenerated completely by ·OH radicals produced through the reduction of ozone. Calculated overall energy consumptions were less than 10 Wh/m3, demonstrating extremely low energy consumptions. In addition, a mathematical model developed based on the limiting mass transfer rate and post-regeneration could represent general trends in time series data observed in experiments

  13. Block Copolymer Electrolytes: Thermodynamics, Ion Transport, and Use in Solid- State Lithium/Sulfur Cells

    Science.gov (United States)

    Teran, Alexander Andrew

    anode, the compatibility of the sulfur cathode was explored. The sulfur cathode presents many unique challenges, including the generation of soluble lithium polysulfides (Li2Sx, 2 ≤ x ≤ 8) during discharge. The solubility of such species in block copolymers and their effect on morphology was examined. The lithium polysulfides were found to exhibit similar solubility in the block copolymers as in typical organic electrolytes, however induced unusual and unexpected phase behavior in the block copolymers. Inspired by successful efforts to physically confine the soluble lithium polysulfides via nanostructured carbon-sulfur composites in the cathode, our nanostructured block copolymer electrolytes were employed in full electrochemical cells with a lithium metal anode and sulfur cathode. Different cathode compositions, electrolyte additives, and cell architectures were tested. Surprisingly, the polysulfides diffused readily from the cathode through the block copolymer electrolyte, and the normally robust SEO|Li metal interface was detrimentally affected their presence during cycling. The polysulfides appeared to change the mechanical properties of the electrolyte such that intimate contact with the lithium metal was lost. Several promising strategies to overcome this problem were investigated and offer exciting avenues for improvement for future researchers. (Abstract shortened by UMI.).

  14. Electro-thermal impedance spectroscopy applied to an open-cathode polymer electrolyte fuel cell

    Science.gov (United States)

    Engebretsen, Erik; Robinson, James B.; Obeisun, Oluwamayowa; Mason, Tom; Finegan, Donal; Hinds, Gareth; Shearing, Paul R.; Brett, Daniel J. L.

    2016-01-01

    The development of in-situ diagnostic techniques is critical to ensure safe and effective operation of polymer electrolyte fuel cell systems. Infrared thermal imaging is an established technique which has been extensively applied to fuel cells; however, the technique is limited to measuring surface temperatures and is prone to errors arising from emissivity variations and reflections. Here we demonstrate that electro-thermal impedance spectroscopy can be applied to enhance infrared thermal imaging and mitigate its limitations. An open-cathode polymer electrolyte fuel cell is used as a case study. The technique operates by imposing a periodic electrical stimulus to the fuel cell and measuring the consequent surface temperature response (phase and amplitude). In this way, the location of heat generation from within the component can be determined and the thermal conduction properties of the materials and structure between the point of heat generation and the point of measurement can be determined. By selectively 'locking-in' to a suitable modulation frequency, spatially resolved images of the relative amplitude between the current stimulus and temperature can be generated that provide complementary information to conventional temporal domain thermograms.

  15. Electrolyte Composition of Mink (Mustela vison Erythrocytes and Active Cation Transporters of the Cell Membrane

    Directory of Open Access Journals (Sweden)

    Clausen TN

    2001-06-01

    Full Text Available Red blood cells from mink (Mustela vison were characterized with respect to their electrolyte content and their cell membranes with respect to enzymatic activity for cation transport. The intra- and extracellular concentrations of Na+, K+, Cl-, Ca2+ and Mg2+ were determined in erythrocytes and plasma, respectively. Plasma and red cell water content was determined, and molal electrolyte concentrations were calculated. Red cells from male adult mink appeared to be of the low-K+, high-Na+ type as seen in other carnivorous species. The intracellular K+ concentration is slightly higher than the extracellular one and the plasma-to-cell chemical gradient for Na+ is weak, though even the molal concentrations may differ significantly. Consistent with the high intracellular Na+ and low K+ concentrations, a very low or no ouabain-sensitive Na+,K+-ATPase activity and no K+-activated pNPPase activity were found in the plasma membrane fraction from red cells. The Cl- and Mg2+ concentrations expressed per liter cell water were significantly higher in red cells than in plasma whereas the opposite was the case with Ca2+. The distribution of Cl- thus does not seem compatible with an inside-negative membrane potential in mink erythrocytes. In spite of a steep calcium gradient across the red cell membrane, neither a calmodulin-activated Ca2+-ATPase activity nor an ATP-activated Ca2+-pNPPase activity were detectable in the plasma membrane fraction. The origin of a supposed primary Ca2+ gradient for sustaining of osmotic balance thus seems uncertain.

  16. Fabrication of electrolytic cell for online post-column electrochemical derivatization in ion chromatography

    International Nuclear Information System (INIS)

    Highlight: ► An electrolytic cell including ruthenium modified titanium electrode was fabricated. ► Ion chromatography/electrochemical derivatization/fluorescence detection was developed. ► Strong oxidation capacity of this EC was obtained by using the Ru/Ti electrode with large surface area. - Abstract: An electrolytic cell (EC), composed of two ruthenium-plated titanium electrodes separated by cation-exchange membranes, was fabricated and evaluated for online postcolumn derivatization in ion chromatography (IC). Folic acid (FA) and methotrexate (MTX) were preliminarily used as prototype analytes to test the performance of EC. After separation by an anion exchange column, FA and MTX, which emit very weak fluorescence when excited, were electrochemically oxidized online in the anode chamber of the EC. The compounds with strong fluorescence, which are oxidation products, were detected by the fluorescence detector. The phosphate buffer solution (100 mM KH2PO4) served as an optimal eluent for anion exchange chromatographic separation and a suitable supporting electrolyte for electro-oxidation, leading to ideal compatibility between IC separation and the postcolumn electrochemical derivatization. For the presently proposed method, the linear ranges were from 0.01 mg L−1 to 5 mg L−1 for both FA and MTX. The detection limits of FA and MTX were 1.8 and 2.1 μg L−1, and the relative standard deviations (RSD, n = 7) were 2.9% and 3.6%, respectively. The method was applied for the simultaneous determination of FA and MTX in the plasma of patients being treated for rheumatoid arthritis. The determination of MTX in the urine of the patients of diffuse large B cell lymphoma was also demonstrated.

  17. Fabrication of electrolytic cell for online post-column electrochemical derivatization in ion chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Wu Shuchao [Department of Chemistry, Xixi Campus, Zhejiang University, Hangzhou 310028, Zhejiang (China); Xu Wei [State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310028, Zhejiang (China); Yang Bingcheng [School of Pharmacy, East China University of Science and Technology, Shanghai 200237 (China); Ye Mingli [Thermofisher scientific (China), Shanghai 201203 (China); Zhang Peimin [Department of Chemistry, Xixi Campus, Zhejiang University, Hangzhou 310028, Zhejiang (China); Shentu Chao [College of Biology and Environmental Engineering, Zhejiang Shuren University, Hangzhou 310015 (China); Zhu Yan, E-mail: zhuyan@zju.edu.cn [Department of Chemistry, Xixi Campus, Zhejiang University, Hangzhou 310028, Zhejiang (China)

    2012-07-20

    Highlight: Black-Right-Pointing-Pointer An electrolytic cell including ruthenium modified titanium electrode was fabricated. Black-Right-Pointing-Pointer Ion chromatography/electrochemical derivatization/fluorescence detection was developed. Black-Right-Pointing-Pointer Strong oxidation capacity of this EC was obtained by using the Ru/Ti electrode with large surface area. - Abstract: An electrolytic cell (EC), composed of two ruthenium-plated titanium electrodes separated by cation-exchange membranes, was fabricated and evaluated for online postcolumn derivatization in ion chromatography (IC). Folic acid (FA) and methotrexate (MTX) were preliminarily used as prototype analytes to test the performance of EC. After separation by an anion exchange column, FA and MTX, which emit very weak fluorescence when excited, were electrochemically oxidized online in the anode chamber of the EC. The compounds with strong fluorescence, which are oxidation products, were detected by the fluorescence detector. The phosphate buffer solution (100 mM KH{sub 2}PO{sub 4}) served as an optimal eluent for anion exchange chromatographic separation and a suitable supporting electrolyte for electro-oxidation, leading to ideal compatibility between IC separation and the postcolumn electrochemical derivatization. For the presently proposed method, the linear ranges were from 0.01 mg L{sup -1} to 5 mg L{sup -1} for both FA and MTX. The detection limits of FA and MTX were 1.8 and 2.1 {mu}g L{sup -1}, and the relative standard deviations (RSD, n = 7) were 2.9% and 3.6%, respectively. The method was applied for the simultaneous determination of FA and MTX in the plasma of patients being treated for rheumatoid arthritis. The determination of MTX in the urine of the patients of diffuse large B cell lymphoma was also demonstrated.

  18. Effect of TiO2 Inclusion in the Poly(vinylidene fluoride-co-hexafluoropropylene)-Based Polymer Electrolyte of Dye-Sensitized Solar Cell

    International Nuclear Information System (INIS)

    The lack of long-term stability, however, could occur by the leakage or evaporation of liquid electrolyte components. Many efforts were paid to replace the liquid electrolyte by various types of quasi-solid-state polymer electrolyte. The approach of using polymer electrolytes has been attracted with high interest but usually resulted in lower conversion efficiency than conventional Graetzel cell with liquid electrolyte. Among many polymer electrolytes, the poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) as polymer matrix material in DSSC has been known to be quite useful because of its photoelectrochemical stability under potential application. The previous result of PVdF-HFP polymer electrolyte presented somewhat low conversion efficiency of about 2-3%. We have considered that the low efficiency might be due to the inhibition of ion migration by the viscosity originated from polymer chain obstacles. Thus, we tried to modify the PVdF-HFP polymer electrolyte system to improve ion migration

  19. Properties of solid polymer electrolyte fluorocarbon film. [used in hydrogen/oxygen fuel cells

    Science.gov (United States)

    Alston, W. B.

    1973-01-01

    The ionic fluorocarbon film used as the solid polymer electrolyte in hydrogen/oxygen fuel cells was found to exhibit delamination failures. Polarized light microscopy of as-received film showed a lined region at the center of the film thickness. It is shown that these lines were not caused by incomplete saponification but probably resulted from the film extrusion process. The film lines could be removed by an annealing process. Chemical, physical, and tensile tests showed that annealing improved or sustained the water contents, spectral properties, thermo-oxidative stability, and tensile properties of the film. The resistivity of the film was significantly decreased by the annealing process.

  20. Fabrication of Monolithic Dye-Sensitized Solar Cell Using Ionic Liquid Electrolyte

    OpenAIRE

    Seigo Ito; Kaoru Takahashi

    2012-01-01

    To improve the durability of dye-sensitized solar cells (DSCs), monolithic DSCs with ionic liquid electrolyte were studied. Deposited by screen printing, a carbon layer was successfully fabricated that did not crack or peel when annealing was employed beforehand. Optimized electrodes exhibited photovoltaic characteristics of 0.608 V open-circuit voltage, 6.90 cm−2 mA short-circuit current, and 0.491 fill factor, yielding 2.06% power conversion efficiency. The monolithic DSC using ionic liquid...

  1. 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...

  2. Using a Quasipotential Transformation for Modeling Diffusion Media inPolymer-Electrolyte Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Adam Z.; Newman, John

    2008-08-29

    In this paper, a quasipotential approach along with conformal mapping is used to model the diffusion media of a polymer-electrolyte fuel cell. This method provides a series solution that is grid independent and only requires integration along a single boundary to solve the problem. The approach accounts for nonisothermal phenomena, two-phase flow, correct placement of the electronic potential boundary condition, and multilayer media. The method is applied to a cathode diffusion medium to explore the interplay between water and thermal management and performance, the impact of the rib-to-channel ratio, and the existence of diffusion under the rib and flooding phenomena.

  3. Electrochemical behavior of heavily cycled nickel electrodes in Ni/H2 cells containing electrolytes of various KOH concentrations

    Science.gov (United States)

    Lim, H. S.; Verzwyvelt, S. A.

    1989-01-01

    A study has been made of charge and discharge voltage changes with cycling of Ni/H2 cells containing electrolytes of various KOH concentrations. A study has also been made of electrochemical behavior of the nickel electrodes from the cycled Ni/H2 cells as a function of overcharge amounts. Discharge voltages depressed gradually with cycling for cells having high KOH concentrations (31 to 36 percent), but the voltages increased for those having low KOH concentrations (21 to 26 percent). To determine if there was a crystallographic change of the active material due to cycling, electrochemical behavior of nickel electrodes was studied in an electrolyte flooded cell containing either 31 or 26 percent KOH electrolyte as a function of the amount of overcharge. The changes in discharge voltage appear to indicate crystal structure changes of active material from gamma-phase to beta-phase in low KOH concentrations, and vice versa in high KOH concentration.

  4. Improved efficiency and stability of flexible dye sensitized solar cells on ITO/PEN substrates using an ionic liquid electrolyte.

    Science.gov (United States)

    Han, Yu; Pringle, Jennifer M; Cheng, Yi-Bing

    2015-01-01

    Flexible dye-sensitized solar cells (DSSCs) built on plastic substrates have attracted great interest as they are lightweight and can be roll-to-roll printed to accelerate production and reduce cost. However, plastic substrates such as PEN and PET are permeable to water, oxygen and volatile electrolyte solvents, which is detrimental to the cell stability. Therefore, to address this problem, in this work, an ionic liquid (IL) electrolyte is used to replace the volatile solvent electrolyte. The initial IL-based devices only achieved around 50% of the photovoltaic conversion efficiency of the cells using the solvent electrolyte. Current-voltage and electrochemical impedance spectroscopy (EIS) analysis of the cells in the dark indicated that this lower efficiency mainly originated from (i) a lack of blocking layer to reduce recombination, and (ii) a lower charge collection efficiency. To combat these problems, cells were developed using a 12 nm thick blocking layer, produced by atomic layer deposition, and 1 μm thick P25 TiO2 film sensitized with the hydrophobic MK-2 dye. These flexible DSSCs utilizing an IL electrolyte exhibit significantly improved efficiencies and a <10% drop in performance after 1000 h aging at 60°C under continuous light illumination. PMID:25476521

  5. Fabrication of thin yttria-stabilized-zirconia dense electrolyte layers by inkjet printing for high performing solid oxide fuel cells

    Science.gov (United States)

    Esposito, Vincenzo; Gadea, Christophe; Hjelm, Johan; Marani, Debora; Hu, Qiang; Agersted, Karsten; Ramousse, Severine; Jensen, Søren Højgaard

    2015-01-01

    In this work, we present how a low-cost HP Deskjet 1000 inkjet printer was used to fabricate a 1.2 μm thin, dense and gas tight 16 cm2 solid oxide fuel cells (SOFC) electrolyte. The electrolyte was printed using an ink made of highly diluted (ink was designed to be a highly dispersed, long term stable colloidal suspension, with optimal printability characteristics. The electrolyte was made by a multiple printing procedure, which ensures coverage of the several flaws occurring in a single printing pass. Together with an optimized sintering procedure this resulted in good adhesion and densification of the electrolyte. The SOFC exhibited a close-to-theoretical open circuit voltage and a remarkable peak power density above 1.5 W cm-2 at 800 °C.

  6. Efficient polymer solar cells employing a non-conjugated small-molecule electrolyte

    Science.gov (United States)

    Ouyang, Xinhua; Peng, Ruixiang; Ai, Ling; Zhang, Xingye; Ge, Ziyi

    2015-08-01

    Polymer solar cells have drawn a great deal of attention due to the attractiveness of their use in renewable energy sources that are potentially lightweight and low in cost. Recently, numerous significant research efforts have resulted in polymer solar cells with power conversion efficiencies in excess of 9% (ref. 1). Nevertheless, further improvements in performance are sought for commercial applications. Here, we report polymer solar cells with a power conversion efficiency of 10.02% that employ a non-conjugated small-molecule electrolyte as an interlayer. The material offers good contact for photogenerated charge carrier collection and allows optimum photon harvesting in the device. Furthermore, the enhanced performance is attributed to improved electron mobility, enhanced active-layer absorption and properly active-layer microstructures with optimal horizontal phase separation and vertical phase gradation. Our discovery opens a new avenue for single-junction devices by fully exploiting the potential of various material systems with efficiency over 10%.

  7. Visualization of Water Accumulation Process in Polymer Electrolyte Fuel Cell Using Neutron Radiography

    Science.gov (United States)

    Murakawa, Hideki; Sugimoto, Katsumi; Kitamura, Nobuki; Sawada, Masataka; Asano, Hitoshi; Takenaka, Nobuyuki; Saito, Yasushi

    In order to clarify the water-accumulation phenomena in an operating polymer electrolyte fuel cell (PEFC), the water distribution in a small fuel cell was measured in the through-plane direction by using neutron radiography. The fuel cell had nine parallel channels for classifying the water-accumulation process in the gas diffusion layer (GDL) under the lands and channels. The experimental results were compared with numerical results. The water accumulation in the GDL under the lands was larger than that under the channels during the period of early PEFC operation. The difference of the water accumulation in the GDL under the land and channel was related to the water vapor. Because of the land, the vapor fraction in the GDL under the land was also higher than that under the channel. As a result, condensation was easy to occur in the GDL under the land.

  8. Table 2.4. Cell voltages with solid state electrolyte systems

    Science.gov (United States)

    Holze, R.

    This document is part of Volume 9 `Electrochemistry', Subvolume A, of Landolt-Börnstein - Group IV `Physical Chemistry'. The document lists normal voltages of cells with solid state electrolyte systems. The cells are composed of the following materials: silver (Ag), aluminium (Al), barium (Ba), bismuth (Bi), carbon (C), cadmium (Cd), cobalt (Co), chromium (Cr), cesium (Cs), copper (Cu), iron (Fe), germanium (Ge), hafnium (Hf), iridium (Ir), potassium (K), lanthanum (La), lithium (Li), magnesium (Mg), manganese (Mn), molybdenum (Mo), nitrogen (N), natrium (Na), niobium (Nb), neodymium (Nd), nickel (Ni), lead (Pb), palladium (Pd), rhodium (Rh), ruthenium (Ru), antimony (Sb), samarium (Sm), tin (Sn), strontium (Sr), tantalum (Ta), tellurium (Te), thorium (Th), thallium (Tl), uranium (U), yttrium (Y), zinc (Zn), zirconium (Zr). The compositions of the cells are given along with, where available, the temperatures of mesurements of the voltages.

  9. Dynamic water management of polymer electrolyte membrane fuel cells using intermittent RH control

    KAUST Repository

    Hussaini, I.S.

    2010-06-01

    A novel method of water management of polymer electrolyte membrane (PEM) fuel cells using intermittent humidification is presented in this study. The goal is to maintain the membrane close to full humidification, while eliminating channel flooding. The entire cycle is divided into four stages: saturation and de-saturation of the gas diffusion layer followed by de-hydration and hydration of membrane. By controlling the duration of dry and humid flows, it is shown that the cell voltage can be maintained within a narrow band. The technique is applied on experimental test cells using both plain and hydrophobic materials for the gas diffusion layer and an improvement in performance as compared to steady humidification is demonstrated. Duration of dry and humid flows is determined experimentally for several operating conditions. © 2010 Elsevier B.V. All rights reserved.

  10. A techno-economic analysis of decentralized electrolytic hydrogen production for fuel cell vehicles

    International Nuclear Information System (INIS)

    Fueling is a central issue in the development of fuel cell systems, especially for transportation applications. Which fuels will be used to provide the necessary hydrogen and what kind of production / distribution infrastructure will be required are key questions for the large scale market penetration of fuel cell vehicles. Methanol, gasoline and hydrogen are currently the three most seriously considered fuel options. Primarily because of economic considerations, these energy currencies would all be largely produced from fossil fuel sources in the near future. One problem in using fossil fuel sources as a feedstock is their associated emissions, in particular greenhouse gases. This paper presents some elements of a study currently underway to assess the techno-economic prospects of decentralized electrolytic hydrogen production for fuel cell vehicles

  11. Miniaturized polymer electrolyte fuel cell (PEFC) stack using micro structured bipolar plate

    Energy Technology Data Exchange (ETDEWEB)

    Veziridis, Z.; Scherer, G.G.; Marmy, Ch.; Glaus, F. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    In Polymer Electrolyte Fuel Cell (PEFC) technology the reducing of volume and mass of the fuel cell stack and the improvement of catalyst utilization are of great interest. These parameters affect applicability and system cost. In this work we present an alternative way for reducing the stack volume by combining gas distribution and catalytic active area in one plate. Micro machined glassy carbon electrodes serve as support material for the platinum catalyst, as well as gas distributor at the same time. A comparison of these electrodes with conventional platinum-black gas diffusion electrodes under fuel cell conditions shows that the new system is a promising electrode type for enhanced power density and catalyst utilization. (author) 3 figs., 5 refs.

  12. Improved electrochemical in-situ characterization of polymer electrolyte membrane fuel cell stacks

    Science.gov (United States)

    Hartung, I.; Kirsch, S.; Zihrul, P.; Müller, O.; von Unwerth, T.

    2016-03-01

    In-situ diagnostics for single polymer electrolyte membrane fuel cells are well known and established. Comparable stack level techniques are urgently needed to enhance the understanding of degradation during real system operation, but have not yet reached a similar level of sophistication. We have therefore developed a new method for the quantification of the hydrogen crossover current in stacks, which in combination with a previously published technique now allows a clear quantitative characterization of the individual cells' membranes and electrodes. The limits of the reported methods are theoretically assessed and application is then demonstrated on automotive short stacks. The results prove to be highly reproducible and are validated for individual cells of the respective stacks by direct comparison with cyclic voltammetry results, showing good quantitative agreement for the hydrogen crossover current, the double layer capacitance and the electrochemically active surface area.

  13. Fuel cells using ionic liquids as electrolyte and operating at room temperature; Celulas de combustivel utilizando como eletrolito liquidos ionicos e operando a temperatura ambiente

    Energy Technology Data Exchange (ETDEWEB)

    Botton, Janine Padilha; Souza, Roberto Fernando de; Goncalves, Reinaldo Simoes; Dupont, Jairton [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Inst. de Quimica], e-mail: janine@iq.ufrgs.br

    2004-07-01

    The room temperature imidazolium based ionic liquids, such as 1-n-butyl-3-methylimidazolium tetrafluoroborate (BMI.BF4) are outstanding electrolytes for fuel cells. A 67% overall cell efficiency is achieve using these liquids as supporting electrolytes for a commercially available alkaline fuel cell (AFC) at room temperature operating with air and hydrogen at atmospheric pressure. (author)

  14. Development of electrically conductive DLC coated stainless steel separators for polymer electrolyte membrane fuel cell

    International Nuclear Information System (INIS)

    Polymer electrolyte fuel cell (PEFC) as one of generation devices of electrical power is rapidly expanding the market as clean energy instead of petroleum and atomic energy. Residential fuel cell goes into quantity production and introduction of fuel cell for use in automobiles starts in the year 2015 in Japan. Critical subject for making fuel cell expand is how to reduce cost of fuel cell. In this paper we describe about separator plate which domains large ratio of cost in fuel cell stack. In present time, carbon is used in material of residential fuel cell separator. Metal separators are developed in fuel cell for use in automobiles because of need of mechanical strength at first. In order to make fuel cell expand in market, further cost reduction is required. But the metal separator has problem that by using metal separator contact resistance occurred by metal corrosion increases and catalyst layer and membrane degrade. In recent time we found out to protect from corrosion and dissolution of metals by coating the film of porous free conductive DLC with plasma ion implantation and deposition technology that we have developed. Film of electrically conductive DLC was formed with high speed of 13 μm/hr by ICP plasma, and coating cost breakout was performed.

  15. Evidence for Active Electrolyte Transport by Two-Dimensional Monolayers of Human Salivary Epithelial Cells.

    Science.gov (United States)

    Hegyesi, Orsolya; Földes, Anna; Bori, Erzsébet; Németh, Zsolt; Barabás, József; Steward, Martin C; Varga, Gábor

    2015-12-01

    Functional reconstruction of lost tissue by regenerative therapy of salivary glands would be of immense benefit following radiotherapy or in the treatment of Sjogren's syndrome. The purpose of this study was to develop primary cultures of human salivary gland cells as potential regenerative resources and to characterize their acinar/ductal phenotype using electrophysiological measurements of ion transport. Human salivary gland cultures were prepared either from adherent submandibular gland cells (huSMG) or from mixed adherent and nonadherent cells (PTHSG) and were cultivated in Hepato-STIM or minimum essential medium (MEM). Expression of key epithelial marker proteins was determined by quantitative reverse transcription polymerase chain reaction (RT-PCR). Transepithelial electrical resistance (TER) was monitored following seeding the cells on Transwell membranes. Transepithelial ion transport was estimated by short-circuit current (Isc) measurements in an Ussing chamber. Both huSMG and PTHSG cells showed epithelial characteristics when cultivated in Hepato-STIM, while fibroblast-like elements dominated in MEM. Compared to intact tissue, cultivation of the cells resulted in substantial decreases in AQP5 and NKCC1 expression and moderate increases in claudin-1 and ENaC expression. Both cultures achieved high TER and transepithelial electrolyte movement in Hepato-STIM, but not in MEM. The Isc was substantially reduced by basolateral Cl(-) and bicarbonate withdrawal, indicating the involvement of basolateral-to-apical anion transport, and by the blockade of apical ENaC by amiloride, indicating the involvement of apical-to-basolateral Na(+) transport. An almost complete inhibition was observed following simultaneous ENaC block and withdrawal of the two anions. Isc was enhanced by either apical adenosine triphosphate (ATP) or basolateral carbachol application, but not by forskolin, confirming the expected role of Ca(2+)-activated regulatory pathways in electrolyte

  16. A UV-prepared linear polymer electrolyte membrane for dye-sensitized solar cells

    International Nuclear Information System (INIS)

    The effects of LiClO4 and LiFS3SO3 on poly(glycidyl methacrylate)-based solid polymer electrolyte and its photoelectrochemical performance in a dye sensitized solar cell consisting of FTO/TiO2–dye/P(GMA)–LiClO4–EC/Pt were investigated. The electrochemical stability of films was studied by cyclic voltammetry (CV). The highest ionic conductivities obtained were 4.2×10−5 and 3.7×10−6 S cm−1 for the film containing 30 wt% LiClO4 and 25 wt% LiCF3SO3, respectively. The polymer electrolytes showed electrochemical stability windows up to 3 V and 2.8 V for LiClO4 and LiCF3SO3, respectively. The assembled dye-sensitized solar cell showed a sunlight conversion efficiency of 0.679% (Jsc=3 mA cm−2, Voc=0.48 V and FF=0.47), under light intensity of 100 mW cm−2

  17. Preparation and investigation of cheap polymer electrolyte membranes for fuel cells

    DEFF Research Database (Denmark)

    Larsen, Mikkel Juul; Ma, Yue; Lund, Peter Brilner;

    The electrolyte of choice for low temperature polymer electrolyte fuel cells (PEFCs) has tra­di­ti­o­nal­ly been DuPontTM Nafion® membranes or similar poly(perfluorosulfonic acid)s. The chemical struc­ture and morphology in the hydrated state of Nafion® is shown in figure 1 from which it is seen...... methanol crossover, and relatively poor thermal stability constitute seri­ous drawbacks with respect to their fuel cell use. [ii], [iii], [iv] These aspects propel the search for cheaper and better alternatives.           In this study membrane systems consisting of a hydrophobic poly......­tro­ly­tic pro­per­ti­es. Grafting with a fraction of DVB in the order of 1-2 vol-% of the total mo­no­mers seems to be advantageous for both of the two grafting sys­tems as a com­pro­mise between high chemical stability and good proton con­duc­tivity of the final membrane. The use of methyl­sty­rene and t...

  18. A UV-prepared linear polymer electrolyte membrane for dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Imperiyka, M., E-mail: imperiyka@gmail.com [Faculty of Arts and Sciences, Kufra Campus, University of Benghazi, Al Kufrah (Libya); Ahmad, A.; Hanifah, S.A. [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Polymer Research Center, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Bella, F. [Center for Space Human Robotics @Polito, Istituto Italiano di Tecnologia, Corso Trento 21, 10129 Torino (Italy); Department of Applied Science and Technology – DISAT, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy)

    2014-10-01

    The effects of LiClO{sub 4} and LiFS{sub 3}SO{sub 3} on poly(glycidyl methacrylate)-based solid polymer electrolyte and its photoelectrochemical performance in a dye sensitized solar cell consisting of FTO/TiO{sub 2}–dye/P(GMA)–LiClO{sub 4}–EC/Pt were investigated. The electrochemical stability of films was studied by cyclic voltammetry (CV). The highest ionic conductivities obtained were 4.2×10{sup −5} and 3.7×10{sup −6} S cm{sup −1} for the film containing 30 wt% LiClO{sub 4} and 25 wt% LiCF{sub 3}SO{sub 3}, respectively. The polymer electrolytes showed electrochemical stability windows up to 3 V and 2.8 V for LiClO{sub 4} and LiCF{sub 3}SO{sub 3}, respectively. The assembled dye-sensitized solar cell showed a sunlight conversion efficiency of 0.679% (J{sub sc}=3 mA cm{sup −2}, V{sub oc}=0.48 V and FF=0.47), under light intensity of 100 mW cm{sup −2}.

  19. Fabrication of electrolytic cell for online post-column electrochemical derivatization in ion chromatography.

    Science.gov (United States)

    Wu, Shuchao; Xu, Wei; Yang, Bingcheng; Ye, Mingli; Zhang, Peimin; Shen-Tu, Chao; Zhu, Yan

    2012-07-20

    An electrolytic cell (EC), composed of two ruthenium-plated titanium electrodes separated by cation-exchange membranes, was fabricated and evaluated for online postcolumn derivatization in ion chromatography (IC). Folic acid (FA) and methotrexate (MTX) were preliminarily used as prototype analytes to test the performance of EC. After separation by an anion exchange column, FA and MTX, which emit very weak fluorescence when excited, were electrochemically oxidized online in the anode chamber of the EC. The compounds with strong fluorescence, which are oxidation products, were detected by the fluorescence detector. The phosphate buffer solution (100 mM KH(2)PO(4)) served as an optimal eluent for anion exchange chromatographic separation and a suitable supporting electrolyte for electro-oxidation, leading to ideal compatibility between IC separation and the postcolumn electrochemical derivatization. For the presently proposed method, the linear ranges were from 0.01 mg L(-1) to 5 mg L(-1) for both FA and MTX. The detection limits of FA and MTX were 1.8 and 2.1 μg L(-1), and the relative standard deviations (RSD, n=7) were 2.9% and 3.6%, respectively. The method was applied for the simultaneous determination of FA and MTX in the plasma of patients being treated for rheumatoid arthritis. The determination of MTX in the urine of the patients of diffuse large B cell lymphoma was also demonstrated. PMID:22713918

  20. Prism-patterned Nafion membrane for enhanced water transport in polymer electrolyte membrane fuel cell

    Science.gov (United States)

    Kim, Sang Moon; Kang, Yun Sik; Ahn, Chiyeong; Jang, Segeun; Kim, Minhyoung; Sung, Yung-Eun; Yoo, Sung Jong; Choi, Mansoo

    2016-06-01

    Here, we report a simple and effective strategy to enhance the performance of the polymer electrolyte membrane fuel cell by imprinting prism-patterned arrays onto the Nafion membrane, which provides three combined effects directly related to the device performance. First, a locally thinned membrane via imprinted micro prism-structures lead to reduced membrane resistance, which is confirmed by electrochemical impedance spectroscopy. Second, increments of the geometrical surface area of the prism-patterned Nafion membrane compared to a flat membrane result in the increase in the electrochemical active surface area. Third, the vertically asymmetric geometry of prism structures in the cathode catalyst layer lead to enhanced water transport, which is confirmed by oxygen gain calculation. To explain the enhanced water transport, we propose a simple theoretical model on removal of water droplets existing in the asymmetric catalyst layer. These three combined effects achieved via incorporating prism patterned arrays into the Nafion membrane effectively enhance the performance of the polymer electrolyte membrane fuel cell.

  1. Density functional theory calculations of H/D isotope effects on polymer electrolyte membrane fuel cell operations

    Energy Technology Data Exchange (ETDEWEB)

    Yanase, Satoshi; Oi, Takao [Sophia Univ., Tokyo (Japan). Faculty of Science and Technology

    2015-10-01

    To elucidate hydrogen isotope effects observed between fuel and exhaust hydrogen gases during polymer electrolyte membrane fuel cell operations, H-to-D reduced partition function ratios (RPFRs) for the hydrogen species in the Pt catalyst phase of the anode and the electrolyte membrane phase of the fuel cell were evaluated by density functional theory calculations on model species of the two phases. The evaluation yielded 3.2365 as the value of the equilibrium constant of the hydrogen isotope exchange reaction between the two phases at 39 C, which was close to the experimentally estimated value of 3.46-3.99 at the same temperature. It was indicated that H{sup +} ions on the Pt catalyst surface of the anode and H species in the electrolyte membrane phase were isotopically in equilibrium with one another during fuel cell operations.

  2. Zinc-air cell with KOH-treated agar layer between electrode and electrolyte containing hydroponics gel

    Energy Technology Data Exchange (ETDEWEB)

    Otham, R. [International Islamic University, Kuala Lumpur (Malaysia); Yahaya, A. H. [University of Malaya, Dept. of Chemistry, Kuala Lumpur (Malaysia); Arof, A. K. [University of Malaya, Dept. of Physics, Kuala Lumpur (Malaysia)

    2002-07-01

    Zinc-air electrochemical power sources possess the highest density compared to other zinc anode batteries, due their free and unlimited supply from the ambient air. In this experiment zinc-air cells have been fabricated employing hydroponics gel as an alternative alkaline electrolyte gelling agent. Thin KOH-treated agar layer was applied between the electrode-electrolyte interfaces which produced significant enhancement of the cells' capacities, indicating that the application of thin agar layer will improve the electrode-gelled electrolyte interfaces. Promising results have been achieved with porous zinc anode prepared from dried zinc-graphite-gelatinized agar paste; e g. a zinc-air cell employing a porous zinc anode has demonstrated a capacity of 1470 mAh rated at 0.1 A continuous discharge. 32 refs., 9 figs.

  3. Density functional theory calculations of H/D isotope effects on polymer electrolyte membrane fuel cell operations

    International Nuclear Information System (INIS)

    To elucidate hydrogen isotope effects observed between fuel and exhaust hydrogen gases during polymer electrolyte membrane fuel cell operations, H-to-D reduced partition function ratios (RPFRs) for the hydrogen species in the Pt catalyst phase of the anode and the electrolyte membrane phase of the fuel cell were evaluated by density functional theory calculations on model species of the two phases. The evaluation yielded 3.2365 as the value of the equilibrium constant of the hydrogen isotope exchange reaction between the two phases at 39 C, which was close to the experimentally estimated value of 3.46-3.99 at the same temperature. It was indicated that H+ ions on the Pt catalyst surface of the anode and H species in the electrolyte membrane phase were isotopically in equilibrium with one another during fuel cell operations.

  4. High-voltage liquid-electrolyte microbatteries composed of serial unit cells defined by the surface-tension effect

    International Nuclear Information System (INIS)

    We present high-voltage liquid-electrolyte microbatteries, inspired by the high-voltage generation mechanism of electric eels using serially connected unit cells. Compared to the previous stacked micropower sources, the present microbatteries achieve easy liquid-electrolyte filling with reduced charging time. In order to isolate each cell, we purge air into the liquid electrolyte filled in a channel layer, with three types of surface-tension valves (cell-front, outlet and cell-end valves). We design and characterize four different prototypes of microbatteries: C1, C10, C20 and C40, composed of the serial interconnection of 1, 10, 20 and 40 unit cells, respectively. In the experimental study, we measure threshold pressures of the three surface tension valves of cell-front, outlet and cell-end valves as 460 ± 47, 1000 ± 53 and 2800 ± 170 Pa, respectively. The average charging time of C40 has been measured as 26.8 ± 4.9 s where the electrolyte and air flow rates are 100 and 200 μl min−1, respectively. The prototypes of the microbattery C40 show a maximum voltage of 12 V, a maximum power density of 110 μW cm−2 and a maximum power capacity of 2.1 μAh cm−2. The present microbatteries have the potential for application in high-voltage portable power sources

  5. Synthesis and Characterization of a Gel-Type Electrolyte with Ionic Liquid Added for Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Le-Yan Shi

    2013-01-01

    Full Text Available This study intends to develop the electrolyte needed in dye-sensitized solar cells (DSSCs. Moreover, three different ionic liquids in different molalities are added to the gel-type electrolyte. Experimental results show that the DSSC composed of the gel-type electrolyte with no ionic liquid added can acquire 4.13% photoelectric conversion efficiency. However, the DSSC composed of the gel-type electrolyte with 0.4 M of 1-butyl-3-methylimidazolium chloride added has an open-circuit voltage of 810 mV, a short-circuit current density of 9.56 mA/cm2, and photoelectric conversion efficiency reaching 4.89%. Comparing this DSSC with the DSSC with no ionic liquid added, the photoelectric conversion efficiency can be enhanced by 18.4%. As to durability, the DSSC composed of the gel-type electrolyte with ionic liquid added still has a photoelectric conversion efficiency of 3.28% on the 7th day after it is stored in an enclosed space and maintains 0.72% efficiency on the 14th day. When the proposed DSSC is compared with the DSSC prepared by using a liquid-type electrolyte, the durability of its photoelectric conversion efficiency can be increased by 7 times.

  6. Pore-filled electrolyte membranes for facile fabrication of long-term stable dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Graphical abstract: Display Omitted -- Highlights: •Pore-filled film electrolytes (PFEMs) were investigated for facile DSSC fabrication. •Optimal mixed solvent was suggested to enhance the long-term stability of DSSCs. •The PFEMs promised both the excellent thermal stability and energy efficiency. •Thephotovoltaic efficiency was well correlated with porous structure of substrates. -- ABSTRACT: Pore-filled electrolyte membranes (PFEMs) have been prepared by employing an optimized porous substrate and stable electrolyte composition for a facile manufacturing process of dye-sensitized solar cells (DSSCs). The PFEMs could be easily loaded into a photovoltaic device without adding a traditional electrolyte injection through a hole. In order to meet the requirements of both high energy conversion efficiency and proper long-term stability, three different solvents with high boiling point, i.e. valeronitrile, dimethyl sulfoxide, and dimethylacetamide, were appropriately mixed as a volumetric ratio of 7:2:1, respectively. As a result, similar conductivity and viscosity as well as better chemical stability were obtained compared to those of conventional 3-methoxypropionitrile-based electrolyte. In addition, linear relations were observed between the photovoltaic efficiency and porous film properties (i.e. porosity and tortuosity). The DSSC employing the PFEM doped with the mixed solvent based electrolyte exhibited the photon-to-current conversion efficiency of 6.30% at one sun condition. Moreover, the long-term stability test fixed at an elevated temperature of 85 °C exhibited outstanding durability of DSSC for 500 h

  7. Further Improvement and System Integration of High Temperature Polymer Electrolyte Membrane Fuel Cells

    DEFF Research Database (Denmark)

    Li, Qingfeng; Jensen, Jens Oluf

    The new development in the field of polymer electrolyte membrane fuel cell (PEMFC) is high temperature PEMFC for operation above 100°C, which has been successfully demonstrated through the previous EC Joule III and the 5th framework programme. New challenges are encountered, bottlenecks for the new...... of the FURIM are in three steps: (1) further improvement of the high temperature polymer membranes and related materials; (2) development of technological units including fuel cell stack, hydrocarbon reformer and afterburner, that are compatible with the HT-PEMFC; and (3) integration of the HT...... catalytic burner are to be developed and integrated with the stack. The key issue of the project is development and improvement of the temperature-resistant polymer membranes with respect to durability, conductivity, mechanical and other properties. For this purpose, basic polymers will be first synthesized...

  8. Further Improvement and System Integration of High Temperature Polymer Electrolyte Membrane Fuel Cells

    DEFF Research Database (Denmark)

    Jensen, Jens Oluf; Li, Qingfeng

    Polymer electrolyte membrane fuel cell (PEMFC) technology based on Nafion membranes can operate at temperatures around 80°C. The new development in the field is high temperature PEMFC for operation above 100°C, which has been successfully demonstrated through the previous EC Joule III and the 5th...... system integration of the high temperature PEMFC. The strategic developments of the FURIM are in three steps: (1) further improvement of the high temperature polymer membranes and related materials; (2) development of technological units including fuel cell stack, hydrocarbon reformer, afterburner and......, conductivity, mechanical and other properties. For this purpose, basic polymers will be first synthesized and optimized. Different routes to functionalize the polymers will be explored to increate proton conductivity. By the development of advanced materials, demonstration of the high temperature PEMFC stack...

  9. Polybenzimidazole and sulfonated polyhedral oligosilsesquioxane composite membranes for high temperature polymer electrolyte membrane fuel cells

    DEFF Research Database (Denmark)

    Aili, David; Allward, Todd; Alfaro, Silvia Martinez;

    2014-01-01

    Composite membranes based on poly(2,2′(m-phenylene)-5,5́bibenzimidazole) (PBI) and sulfonated polyhedral oligosilsesquioxane (S-POSS) with S-POSS contents of 5 and 10wt.% were prepared by solution casting as base materials for high temperature polymer electrolyte membrane fuel cells. With membranes...... based on pure PBI as a reference point, the composite membranes were characterized with respect to spectroscopic and physicochemical properties. After doping with phosphoric acid, the composite membranes showed considerably improved ex situ proton conductivity under anhydrous as well as under fully...... humidified conditions in the 120-180°C temperature range. The conductivity improvements were also confirmed by in situ fuel cell tests at 160°C and further supported by the electrochemical impedance spectroscopy data based on the operating membrane electrode assemblies, demonstrating the technical...

  10. Metallic plate corrosion and uptake of corrosion products by nafion in polymer electrolyte membrane fuel cells.

    Science.gov (United States)

    Bozzini, Benedetto; Gianoncelli, Alessandra; Kaulich, Burkhard; Kiskinova, Maya; Prasciolu, Mauro; Sgura, Ivonne

    2010-07-19

    Nafion contamination by ferrous-alloy corrosion products, resulting in dramatic drops of the Ohmic potential, is a suspected major failure mode of polymer electrolyte membrane fuel cells that make use of metallic bipolar plates. This study demonstrates the potential of scanning transmission X-ray microscopy combined with X-ray absorption and fluorescence microspectroscopy for exploring corrosion processes of Ni and Fe electrodes in contact with a hydrated Nafion film in a thin-layer cell. The imaged morphology changes of the Ni and Fe electrodes and surrounding Nafion film that result from relevant electrochemical processes are correlated to the spatial distribution, local concentration, and chemical state of Fe and Ni species. The X-ray fluorescence maps and absorption spectra, sampled at different locations, show diffusion of corrosion products within the Nafion film only in the case of the Fe electrodes, whereas the Ni electrodes appear corrosion resistant. PMID:20564283

  11. Electrolytes and Electrodes for Electrochemical Cells Operating at 200 - 300 °C

    DEFF Research Database (Denmark)

    Hallinder, Jonathan

    Depletion of oil and increased emissions of CO2 are two major concerns in today’s society, but there is, fortunately, also an increased interest in energy production from renewable sources, such as wind and solar. A drawback with these sources is their intermittent energy production, which can lead...... of interest for synthesis of hydrocarbons and alcohols. The aim of this study was to make use of knowledge from existing electrolysis techniques in order to develop an electrolysis technique that can produce hydrocarbons and alcohols by a single step process using CO2 and steam (and/or hydrogen) as...... and full cells. The electrochemical performance of the fabricated cells was evaluated using electrochemical impedance spectroscopy, cyclic sweep measurements and chronoamperometry. The initial part of the study focused on electrolyte materials in order to find a promising candidate to be implemented...

  12. Cobalt-Based Electrolytes for Dye-Sensitized Solar Cells: Recent Advances towards Stable Devices

    Directory of Open Access Journals (Sweden)

    Federico Bella

    2016-05-01

    Full Text Available Redox mediators based on cobalt complexes allowed dye-sensitized solar cells (DSCs to achieve efficiencies exceeding 14%, thus challenging the emerging class of perovskite solar cells. Unfortunately, cobalt-based electrolytes demonstrate much lower long-term stability trends if compared to the traditional iodide/triiodide redox couple. In view of the large-scale commercialization of cobalt-based DSCs, the scientific community has recently proposed various approaches and materials to increase the stability of these devices, which comprise gelling agents, crosslinked polymeric matrices and mixtures of solvents (including water. This review summarizes the most significant advances recently focused towards this direction, also suggesting some intriguing way to fabricate third-generation cobalt-based photoelectrochemical devices stable over time.

  13. High-efficiency dye-sensitized solar cells using ferrocene-based electrolytes and natural photosensitizers

    International Nuclear Information System (INIS)

    A new and promising dye-sensitized solar cell (DSSC) bilayer design was developed using an Fe2+/Fe3+ (ferrocene) liquid electrolyte and natural dyes extracted from Hypericum perforatum, Rubia tinctorum L. and Reseda luteola. The photovoltaic parameters controlling the device performance were then investigated. A DSSC based on quercetin dye displayed the most efficient solar to electricity conversion efficiency compared with other dyes with a maximum η value of 2.17%. Maximum overall conversion efficiencies under simulated sunlight that was comparable to natural photosynthesis were increased by 15%. The identification of appropriate additives for improving VOC without causing dye degradation may result in further enhancement of cell performance, making the practical application of such systems more suitable for achieving economically viable solar energy devices.

  14. High-efficiency dye-sensitized solar cells using ferrocene-based electrolytes and natural photosensitizers

    Science.gov (United States)

    Sönmezoğlu, Savaş; Akyürek, Cafer; Akin, Seçkin

    2012-10-01

    A new and promising dye-sensitized solar cell (DSSC) bilayer design was developed using an Fe2+/Fe3+ (ferrocene) liquid electrolyte and natural dyes extracted from Hypericum perforatum, Rubia tinctorum L. and Reseda luteola. The photovoltaic parameters controlling the device performance were then investigated. A DSSC based on quercetin dye displayed the most efficient solar to electricity conversion efficiency compared with other dyes with a maximum η value of 2.17%. Maximum overall conversion efficiencies under simulated sunlight that was comparable to natural photosynthesis were increased by 15%. The identification of appropriate additives for improving VOC without causing dye degradation may result in further enhancement of cell performance, making the practical application of such systems more suitable for achieving economically viable solar energy devices.

  15. Bifacial dye-sensitized solar cells based on an ionic liquid electrolyte

    Science.gov (United States)

    Ito, Seigo; Zakeeruddin, Shaik M.; Comte, Pascal; Liska, Paul; Kuang, Daibin; Grätzel, Michael

    2008-11-01

    Solar energy is a promising solution to global energy-related problems because it is clean, inexhaustible and readily available. However, the deployment of conventional photovoltaic cells based on silicon is still limited by cost, so alternative, more cost-effective approaches are sought. Here we report a bifacial dye-sensitized solar cell structure that provides high photo-energy conversion efficiency (~6%) for incident light striking its front or rear surfaces. The design comprises a highly stable ruthenium dye (Z907Na) in combination with an ionic-liquid electrolyte and a porous TiO2 layer. The inclusion of a SiO2 layer between the electrodes to prevent generation of unwanted back current and optimization of the thickness of the TiO2 layer are responsible for the enhanced performance.

  16. A polymer electrolyte fuel cell stack for stationary power generation from hydrogen fuel

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, M.S.; Moeller-Holst, S.; Webb, D.M.; Zawodzinski, C.; Gottesfeld, S. [Los Alamos National Lab., NM (United States). Materials Science and Technology Div.

    1998-08-01

    The objective is to develop and demonstrate a 4 kW, hydrogen-fueled polymer electrolyte fuel cell (PEFC) stack, based on non-machined stainless steel hardware and on membrane/electrode assemblies (MEAs) of low catalyst loadings. The stack is designed to operate at ambient pressure on the air-side and can accommodate operation at higher fuel pressures, if so required. This is to be accomplished by working jointly with a fuel cell stack manufacturer, based on a CRADA. The performance goals are 57% energy conversion efficiency hydrogen-to-electricity (DC) at a power density of 0.9 kW/liter for a stack operating at ambient inlet pressures. The cost goal is $600/kW, based on present materials costs.

  17. Proton conductive inorganic-organic hybrid membranes functionalized with phosphonic acid for polymer electrolyte fuel cell

    Science.gov (United States)

    Umeda, Junji; Suzuki, Masashi; Kato, Masaki; Moriya, Makoto; Sakamoto, Wataru; Yogo, Toshinobu

    Proton conductive sol-gel derived hybrid membranes were synthesized from aromatic derivatives of methoxysilanes and ethyl 2-[3-(dihydroxyphosphoryl)-2-oxapropyl]acrylate (EPA). Two aromatic derivatives of methoxysilanes with different number of methoxy groups were used as the starting materials. Hybrid membranes from difunctional (methyldimethoxysilylmethyl)styrene (MDMSMS(D))/EPA revealed a higher chemical stability and mechanical properties than those from monofunctional (dimethylmethoxysilylmethyl)styrene (DMMSMS(M))/EPA. The membrane-electrode assembly (MEA) using the hybrid membranes as electrolytes worked as a fuel cell at 100 °C under saturated humidity. The DMMSMS(M)/EPA membrane-based MEA showed a larger current density than that from MDMSMS(D)/EPA. On the other hand, the MDMSMS(D)/EPA membrane-based MEA exhibited higher open circuit voltages than the DMMSMS(M)/EPA-based MEA, and was stable during fuel cell operation at 80 °C at least for 48 h.

  18. Proton conductive inorganic-organic hybrid membranes functionalized with phosphonic acid for polymer electrolyte fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Umeda, Junji; Moriya, Makoto; Sakamoto, Wataru; Yogo, Toshinobu [Division of Nanomaterials Science, EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603 (Japan); Suzuki, Masashi; Kato, Masaki [Research and Development Division, Aichi Industrial Technology Institute, Nishi-shinwari, Hitotsugi-cho, Kariya, Aichi 448-0003 (Japan)

    2010-09-15

    Proton conductive sol-gel derived hybrid membranes were synthesized from aromatic derivatives of methoxysilanes and ethyl 2-[3-(dihydroxyphosphoryl)-2-oxapropyl]acrylate (EPA). Two aromatic derivatives of methoxysilanes with different number of methoxy groups were used as the starting materials. Hybrid membranes from difunctional (methyldimethoxysilylmethyl)styrene (MDMSMS(D))/EPA revealed a higher chemical stability and mechanical properties than those from monofunctional (dimethylmethoxysilylmethyl)styrene (DMMSMS(M))/EPA. The membrane-electrode assembly (MEA) using the hybrid membranes as electrolytes worked as a fuel cell at 100 C under saturated humidity. The DMMSMS(M)/EPA membrane-based MEA showed a larger current density than that from MDMSMS(D)/EPA. On the other hand, the MDMSMS(D)/EPA membrane-based MEA exhibited higher open circuit voltages than the DMMSMS(M)/EPA-based MEA, and was stable during fuel cell operation at 80 C at least for 48 h. (author)

  19. Experimental Study of Polymer Electrolyte Membrane Fuel Cell Performance Under Low Operating Temperatures

    International Nuclear Information System (INIS)

    In this study, the performance characteristics of a polymer electrolyte membrane fuel cell (PEMFC) were investigated at low operating temperatures under steady-state and dynamic conditions. The performance of the PEMFC was analyzed according to the external humidifying rate and air stoichiometry. The ohmic resistance was also investigated using EIS tests. At the operating temperature of 35 ℃, voltage fluctuation occurred to a greater degree compared to that at 45 ℃. Therefore, it was found that the air stoichiometry should be higher than 2.5 for the stable operation of the fuel cell. In addition, the relative humidity of the reactant gases should be higher than 60 to reduce the ohmic resistance

  20. Multiplex lithography for multilevel multiscale architectures and its application to polymer electrolyte membrane fuel cell.

    Science.gov (United States)

    Cho, Hyesung; Moon Kim, Sang; Sik Kang, Yun; Kim, Junsoo; Jang, Segeun; Kim, Minhyoung; Park, Hyunchul; Won Bang, Jung; Seo, Soonmin; Suh, Kahp-Yang; Sung, Yung-Eun; Choi, Mansoo

    2015-01-01

    The production of multiscale architectures is of significant interest in materials science, and the integration of those structures could provide a breakthrough for various applications. Here we report a simple yet versatile strategy that allows for the LEGO-like integrations of microscale membranes by quantitatively controlling the oxygen inhibition effects of ultraviolet-curable materials, leading to multilevel multiscale architectures. The spatial control of oxygen concentration induces different curing contrasts in a resin allowing the selective imprinting and bonding at different sides of a membrane, which enables LEGO-like integration together with the multiscale pattern formation. Utilizing the method, the multilevel multiscale Nafion membranes are prepared and applied to polymer electrolyte membrane fuel cell. Our multiscale membrane fuel cell demonstrates significant enhancement of performance while ensuring mechanical robustness. The performance enhancement is caused by the combined effect of the decrease of membrane resistance and the increase of the electrochemical active surface area. PMID:26412619

  1. Electrolytes with Improved Safety Developed for High Specific Energy Li-Ion Cells with Si-Based Anodes

    Science.gov (United States)

    Smart, M. C.; Krause, F. C.; Hwang, C.; Soler, J.; West, W. C.; Ratnakumar, B. V.; Prakash, G. K. S.

    2012-01-01

    A number of electrolyte formulations that have improved safety characteristics have been developed for use with high capacity silicon-based anodes. To improve the compatibility with Si-based anodes, a number of technical approaches have been employed, including: (1) the use of mono-fluoroethylene carbonate (FEC) in conjunction with, or in lieu of, ethylene carbonate (EC), (2) the use of high proportions of fluorinated co-solvents, (3) the use of vinylene carbonate (VC) to stabilize the Si/C electrode, and (4) the use of lithium bis(oxalato)borate (LiBOB) to improve the compatibility of the electrolyte when Si/C electrodes are used in conjunction with high voltage cathodes. Candidate electrolytes were studied in Li/Si-C and Si-C/ Li(MnNiCo)O2 (NMC) coin cells, as well as in larger Si-C/NMC three-electrode cells equipped with lithium reference electrodes. In summary, many electrolytes that contain triphenyl phosphate (TPP), which is used as a flame retardant additive up to concentrations of 15 volume percent, and possess FEC as a co-solvent have been demonstrated to outperform the all-carbonate baseline electrolytes when evaluated in Si-C/ Li(MnNiCo)O2 cells.

  2. 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

  3. Alkaline direct ethanol fuel cell performance using alkali-impregnated polyvinyl alcohol/functionalized carbon nano-tube solid electrolytes

    Science.gov (United States)

    Huang, Chien-Yi; Lin, Jia-Shiun; Pan, Wen-Han; Shih, Chao-Ming; Liu, Ying-Ling; Lue, Shingjiang Jessie

    2016-01-01

    This study investigates the application of a polyvinyl alcohol (PVA)/functionalized carbon nano-tubes (m-CNTs) composite in alkaline direct ethanol fuel cells (ADEFC). The m-CNTs are functionalized with PVA using the ozone mediation method, and the PVA composite containing the modified CNTs is prepared. Adding m-CNT into the PVA matrix enhances the alkaline uptake and the ionic conductivity of the KOH-doped electrolyte. Meanwhile, the m-CNT-containing membrane exhibited a lower swelling ratio and suppressed ethanol permeability compared to the pristine PVA film. The optimal condition for the ADEFC is determined to be under operation at an anode feed of 3 M ethanol in a 5 M KOH solution (at a flow rate of 5 cm3 min-1) with a cathode feed of moisturized oxygen (with a flow rate of 100 cm3 min-1) and the KOH-doped PVA/m-CNT electrolyte. We achieved a peak power density value of 65 mW cm-2 at 60 °C, which is the highest among the ADEFC literature data and several times higher than the proton-exchange direct ethanol fuel cells using sulfonated membrane electrolytes. Therefore, the KOH-doped PVA/m-CNT electrolyte is a suitable solid electrolyte for ADEFCs and has potential for commercialization in alkaline fuel cell applications.

  4. Utilization of mixed oxide materials for solid polymer electrolyte membrane fuel cell

    International Nuclear Information System (INIS)

    Fuel cell technology offers clean, silent and robust sources of energy for our future needs. Among the five common fuel cells widely been used, solid polymer electrolyte membrane fuel cell (SPEFC) gives more advantages in many respects. It is able to generate power more efficiently for both vehicular and stationary in the range of 5 to 500 kW without causing pollution. It's operate at low temperature of 5OoC at an efficiency of 50 to 60 %. Furthermore, it can produce high current density even though it is operating at low temperature (the highest temperature is 90oC) and at the pressure of 600 kPa. It's source of fuel arc hydrogen and oxygen, while discharge very small quantity of water as the product. In this work, the optimization of electrocatalyst for fuel cell electrode using various mixed oxide materials was carried out. The elucidation of active site species that contribute to the performance of the fuel cell was achieved using X-Ray Photoelectron Spectroscopy, X-ray Diffraction and Scanning Electron Microscopy techniques. The result of testing using laboratory scale fuel cell model reveals that the flow rate of fuel gases, the pretreatment of electrocatalysts and the composition of mixed oxide electrocatalysts, play important roles in determining the best performance of the working SPEFC fuel cell system. (Author)

  5. 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...... because the predominant transport mechanism is diffusion. Consequently, operating conditions with a high net water transport from anode to cathode should be avoided as it is important to keep the cathode catalyst layer well humidified in order to prevent high protonic losses. Addition of the micro...

  6. Polymer electrolyte system based on carrageenan-poly(3,4- ethylenedioxythiophene) (PEDOT) composite for dye sensitized solar cell

    Science.gov (United States)

    Ng, C. A.; Camacho, D. H.

    2015-06-01

    Poly(3,4-ethylenedioxythiophene) (PEDOT)-κ-carregeenan polymer electrolyte blend was prepared and incorporated as the electrolyte system in dye-sensitized solar cells (DSSC). Polymer blends prepared with different κ-carrageenan concentrations and molecular weights were investigated. It was found that the conductivity of the polymer blend increases with higher κ-carrageenan concentration, and lowers with degraded κ-carregeenan. The polymer blend was incorporated in a DSSC and yielded a solar cell with efficiency (η) of 0.421%.

  7. Factors determining the gas crossover through pinholes in polymer electrolyte fuel cell membranes

    International Nuclear Information System (INIS)

    Highlights: ► Small defects (10 μm) do not decrease the fuel cell performance. ► The gas diffusion electrode controls the gas crossover through defects. ► Hydrogen permeating through defects is not oxidized quantitatively at the catalyst. ► Liquid water can fill and seal defects and eliminate the gas crossover. - Abstract: Membrane degradation in polymer electrolyte fuel cells often results in pinhole formation, which does not force an immediate fuel cell shutdown, as the performance is still good and the gas crossover is moderate for low membrane defect densities. However, the gas crossover increases locally at defects, which may accelerate chemical polymer decomposition and enlarge the defect. Hence, a fundamental understanding of the gas crossover through small pinholes is required to deduce strategies mitigating fast membrane degradation. Methods are developed to implement pinholes (10 μm) artificially in polymer electrolyte membranes. The pinhole morphology and chemical environment are characterized by X-ray tomographic microscopy and FTIR spectro-microscopy. The gas crossover is measured in situ for different fuel cell operating conditions using a mass spectrometry based method. In saturated environment liquid water can seal pinholes and eliminate the crossover. This sealing effect depends on the pinhole size and the pressure gradient between anode and cathode. Increasing temperature or humidity reduces the gas crossover. Hydrogen, permeating through defects, does not oxidize quantitatively at the cathode catalyst layer, but permeates through the gas diffusion layer (GDL) into the gas channel. Then, the permeability of the GDL, in particular its micro-porous layer, limits the gas crossover through pinholes significantly.

  8. Influences of water in bis-benzimidazole-derivative electrolyte additives to the degradation of the dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Hung-Lin; Yang, Thomas C.-K. [Department of Chemical Engineering, National Taipei University of Technology, No. 1, Section 3, Chung-hsiao East Road, Taipei 106 (China); Lee, Yu-Hui; Huang, Sheng-Tung [Institute of Biotechnology, National Taipei University of Technology, Taipei 106 (China); Su, Chaochin [Institute of Organic and Polymeric Materials, National Taipei University of Technology, Taipei 106 (China)

    2011-01-15

    The chemical stability of dye-sensitized solar cells (DSSC) determines both the cell performance and the cell life-time. The presence of water in the solar cell from surrounding leakage through the imperfection packaging sealants causes the decrease in life-time of photogenerated electrons on the working electrodes, which induces the occurrence of the dark current to the electrolytes and thus leakage current significantly deteriorated the life-time of the DSSC. Reliable electrolyte additives diminishing the influences of water to the DSSCs degradation process becomes a critical issue in maintaining an acceptable cell life-time. In this work, the effects of four benzimidazole derivatives a-d as the electrolyte additives in the presence of water were comprehensively examined by time-dependent photovoltaic performance of the cells. As a result, open-circuit voltage (V{sub oc}), short-circuit current (J{sub sc}), efficiency ({eta}), and fill factor (FF) collected from I-V curves were studied. In addition, electrochemical impedance spectroscopy (EIS) technique was implemented to evaluate the effects of the charge-transfer resistance (R{sub ct}) at the interfaces between TiO{sub 2}/dye/electrolyte. Results showed that the bis-benzimidazole derivative c gives significant improvement in the long-term stability due to the effective protection of the ligands between dye and working electrodes from the attack by environmental water molecules. (author)

  9. Nanosize Copper Dispersed Ionic Liquids As an Electrolyte of New Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Fu-Lin Chen

    2009-01-01

    Full Text Available To enhance the electrical conductivity of the electrolyte for a newly developed dye-sensitized solar cell (DSSC, metallic copper (Cu encapsulated within the carbon shell (Cu@C nanoparticles dispersed in a room temperature ionic liquid (RTIL (e.g., [bmim+][PF6−] has been studied in the present work. By the pulsed-field gradient spin-echo NMR method, the self-diffusion coefficients of cations and anions of the RTIL have been determined. The self-diffusion coefficient of the [bmim+] cations in the RTIL dispersed with 0.08% of Cu@C nanoparticles is increased by 35%. The electrical conductivity of the Cu@C dispersed RTIL is also increased by 65% (1.0 → 2.3 ms/cm. It is very clear the nanosize Cu@C dispersed RTIL with a relatively greater diffusion coefficient and electrical conductivity can be a very effective electrolyte especially utilized in DSSCs.

  10. Theoretical studies on membranes and non-platinum catalysts for polymer electrolyte fuel cells

    International Nuclear Information System (INIS)

    Mechanism of proton transfer among high-density acid groups in the interface between organic and inorganic materials for polymer electrolyte fuel cells has been theoretically examined. It has been clearly shown that the interactions between the phosphate groups at the surface of the inorganic material, zirconium phosphate (ZrP), and the adsorbed water molecules are relatively large and a strong hydrogen-bond network is generated locally. Because of the strong interactions, water molecules can be attached to ZrP and the O–O distance becomes shorter than that in bulk water systems. Because of the short O–O distances and the delocalized charge of each atom, the activation energy of proton transfer at the ZrP surface decreases and causes high proton conductivity even under conditions of high temperature and low humidity. Based on the above studies, the origin of the high proton conductivity of hybrid electrolytes is also discussed. We will also discuss the mechanism of oxygen reduction reaction on non-platinum catalysts such as Ta3N5

  11. High-Efficiency Glass and Printable Flexible Dye-Sensitized Solar Cells with Water-Based Electrolytes

    Directory of Open Access Journals (Sweden)

    Omar Moudam

    2014-01-01

    Full Text Available The performance of a flexible and glass dye-sensitized solar cell (DSSC with water-based electrolyte solutions is described. High concentrations of alkylamidazoliums were used to overcome the deleterious effect of water and, based on this variable, pure water-based electrolyte DSSCs were tested displaying the highest recorded efficiency so far of 3.45% and 6% for flexible and glass cells, respectively, under a simulated air mass 1.5 solar spectrum illumination at 100 mWcm−2. An improvement in the Jsc with high water content and the positive impact of GuSCN on the enhancement of the performance of pure water-based electrolytes were also observed.

  12. The use of poly(vinylpyridine-co-acrylonitrile) in polymer electrolytes for quasi-solid dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Li, Minyu [Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China); Feng, Shujing; Fang, Shibi; Xiao, Xurui; Li, Xueping; Zhou, Xiaowen; Lin, Yuan [Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080 (China)

    2007-04-01

    Poly(vinylpyridine-co-acrylonitrile) (P(VP-co-AN)) was used to form polymer electrolytes for dye-sensitized solar cells (DSSCs). The effects of P(VP-co-AN) on the photovoltaic performances of DSSCs have been investigated with nonaqueous electrolytes containing alkali-iodide and iodine. It was found that the effect of P(VP-co-AN) on V{sub oc} closely related to its amount in the electrolyte. Lower amount of P(VP-co-AN) was benefit for the construction of a solar cell containing P(VP-co-AN) with higher energy conversion efficiency. Chemically crosslinking solidification with backbone polymer P(VP-co-AN) amount of 3% fabricated quasi-solid DSSCs with 10% increased conversion efficiencies with relative to that of the initial liquid DSSCs. (author)

  13. The use of poly(vinylpyridine-co-acrylonitrile) in polymer electrolytes for quasi-solid dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Poly(vinylpyridine-co-acrylonitrile) (P(VP-co-AN)) was used to form polymer electrolytes for dye-sensitized solar cells (DSSCs). The effects of P(VP-co-AN) on the photovoltaic performances of DSSCs have been investigated with nonaqueous electrolytes containing alkali-iodide and iodine. It was found that the effect of P(VP-co-AN) on V oc closely related to its amount in the electrolyte. Lower amount of P(VP-co-AN) was benefit for the construction of a solar cell containing P(VP-co-AN) with higher energy conversion efficiency. Chemically crosslinking solidification with backbone polymer P(VP-co-AN) amount of 3% fabricated quasi-solid DSSCs with 10% increased conversion efficiencies with relative to that of the initial liquid DSSCs

  14. Polymer-metal complex as gel electrolyte for quasi-solid-state dye-sensitized solar cells

    International Nuclear Information System (INIS)

    A kind of polymer-metal complex gel electrolyte is successfully prepared and is used in dye-sensitized solar cells. Raman and X-ray photoelectron spectroscopy confirm the structure of this complex and is found that the metal ion reacts with nitrogen in the polymer. This novel electrolyte shows apparent diffusion coefficient of iodide of 8.37 x 10-7 cm2 s-1 and the energy conversion efficiency of 6.10% when the amount of ZnI2 is 0.04 M. By studying the dissociation active energy of the inorganic salt in electrolytes, we find that the metal salts can dissociate more easily after reacting with polymer and as a result can provide extra free iodide ion. The cell maintains ca. 93% of its initial efficiency after 20 d without further sealing, which shows good long-time stability.

  15. In situ Poly(methyl methacrylate)/Graphene Composite Gel Electrolytes for Highly Stable Dye-Sensitized Solar Cells.

    Science.gov (United States)

    Kang, Yu-il; Moon, Jun Hyuk

    2015-11-01

    Dye-sensitized solar cells (DSCs) with long-term stability are produced using polymer-gel electrolytes (PGEs). In this study, we introduce the formation of PGEs using in situ gelation with poly(methyl methacrylate) (PMMA) particles and graphene fillers that are pre-deposited on the counter electrodes. We obtain a high concentration PMMA-based PGEs (i.e., over 10 wt%). A DSC composed of a PMMA/graphene composite PGEs exhibits an 8.49% photon-to-electric conversion efficiency, which is comparable to conventional liquid electrolyte DSCs. This finding is attributed to increased ion diffusivity and conductivity of the PMMA-based PGEs resulting from the incorporation of graphene nanofillers. The PMMA-based PGE DSCs exhibit highly stable long-term efficiencies, maintaining up to 90% of their initial efficiency during thermal soaking, whereas the efficiencies of liquid electrolyte cells decrease significantly, by up to 60%. PMID:26471468

  16. On the addition of conducting ceramic nanoparticles in solvent-free ionic liquid electrolyte for dye-sensitized solar cells

    KAUST Repository

    Lee, Chuan-Pei

    2009-08-01

    Titanium carbide (TiC) is an extremely hard conducting ceramic material often used as a coating for titanium alloys as well as steel and aluminum components to improve their surface properties. In this study, conducting ceramic nanoparticles (CCNPs) have been used, for the first time, in dye-sensitized solar cells (DSSCs), and the incorporation of TiC nanoparticles in a binary ionic liquid electrolyte on the cell performance has been investigated. Cell conversion efficiency with 0.6 wt% TiC reached 1.68%, which was higher than that without adding TiC (1.18%); however, cell efficiency decreased when the TiC content reached 1.0 wt%. The electrochemical impedance spectroscopy (EIS) technique was employed to analyze the interfacial resistance in DSSCs, and it was found that the resistance of the charge-transfer process at the Pt counter electrode (Rct1) decreased when up to 1.0 wt% TiC was added. Presumably, this was due to the formation of the extended electron transfer surface (EETS) which facilitates electron transfer to the bulk electrolyte, resulting in a decrease of the dark current, whereby the open-circuit potential (VOC) could be improved. Furthermore, a significant increase in the fill factor (FF) for all TiC additions was related to the decrease in the series resistance (RS) of the DSSCs. However, at 1.0 wt% TiC, the largest charge-transfer resistance at the TiO2/dye/electrolyte interface was observed and resulted from the poor penetration of the electrolyte into the porous TiO2. The long-term stability of DSSCs with a binary ionic liquid electrolyte, which is superior to that of an organic solvent-based electrolyte, was also studied. © 2009 Elsevier B.V. All rights reserved.

  17. Ionic liquid-tethered Graphene Oxide/Ionic Liquid Electrolytes for Highly Efficient Dye Sensitized Solar Cells

    International Nuclear Information System (INIS)

    Graphical abstract: - Abstract: Ionic liquid-tethered graphene oxide (IL-GO) are prepared by tethering 1-(3-aminopropyl)-3-methylimi-dazolium bromide to graphene oxide (GO), and followed by anion-exchange with bis(trifluoromethanesulfonyl)imide ions (TFSI−). Environmental friendly ionic liquid-based composite electrolyte for dye sensitized solar cells (DSSCs) without volatile organic solvents is prepared from IL-GO and 1-propyl-3-methylimidazolium iodide (PMII). Incorporation of proper amount of IL-GO significantly increased the conductivity of the electrolyte, the open circuit voltage, the short circuit current density and the conversion efficiency of DSSCs. The dye-sensitized solar cells (DSSCs) containing 4 wt% of IL-GO composite electrolytes show an overall power conversion efficiency of 7.04% under simulated AM 1.5 solar spectrum irradiation at 100 mW cm−2. These results indicate that the DSSCs based on IL-GO/IL composite electrolytes could overcome the drawbacks of volatile liquid electrolytes, and offer a feasible method to fabricate DSSCs in future practical applications

  18. Glass Frit Dissolution Influenced by Material Composition and the Water Content in Iodide/Triiodide Electrolyte of Dye-Sensitized Solar Cells

    OpenAIRE

    Katrine Flarup Jensen; Md. Mahbubur Rahman; Welmoed Veurman; Henning Brandt; Chan Im; Jürgen Wilde; Andreas Hinsch; Jae-Joon Lee

    2013-01-01

    To ensure long-term stable dye-sensitized solar cells (DSCs) and modules, a hermetic sealing is required. This research investigates the chemical stability of I-/I3- redox electrolyte and four different glass frits (GFs). Sintered GF layers were openly exposed to nonaqueous redox electrolyte and redox electrolyte with 1, 5, and 10 wt% H2O in thin, encapsulated cells. The change in I3− absorbance was assigned to a reaction between the GF and I-/I3- electrolyte and was used to evaluate the chem...

  19. A New, Scalable and Low Cost Multi-Channel Monitoring System for Polymer Electrolyte Fuel Cells.

    Science.gov (United States)

    Calderón, Antonio José; González, Isaías; Calderón, Manuel; Segura, Francisca; Andújar, José Manuel

    2016-01-01

    In this work a new, scalable and low cost multi-channel monitoring system for Polymer Electrolyte Fuel Cells (PEFCs) has been designed, constructed and experimentally validated. This developed monitoring system performs non-intrusive voltage measurement of each individual cell of a PEFC stack and it is scalable, in the sense that it is capable to carry out measurements in stacks from 1 to 120 cells (from watts to kilowatts). The developed system comprises two main subsystems: hardware devoted to data acquisition (DAQ) and software devoted to real-time monitoring. The DAQ subsystem is based on the low-cost open-source platform Arduino and the real-time monitoring subsystem has been developed using the high-level graphical language NI LabVIEW. Such integration can be considered a novelty in scientific literature for PEFC monitoring systems. An original amplifying and multiplexing board has been designed to increase the Arduino input port availability. Data storage and real-time monitoring have been performed with an easy-to-use interface. Graphical and numerical visualization allows a continuous tracking of cell voltage. Scalability, flexibility, easy-to-use, versatility and low cost are the main features of the proposed approach. The system is described and experimental results are presented. These results demonstrate its suitability to monitor the voltage in a PEFC at cell level. PMID:27005630

  20. Adsorption behavior of low concentration carbon monoxide on polymer electrolyte fuel cell anodes for automotive applications

    Science.gov (United States)

    Matsuda, Yoshiyuki; Shimizu, Takahiro; Mitsushima, Shigenori

    2016-06-01

    The adsorption behavior of CO on the anode around the concentration of 0.2 ppm allowed by ISO 14687-2 is investigated in polymer electrolyte fuel cells (PEFCs). CO and CO2 concentrations in the anode exhaust are measured during the operation of a JARI standard single cell at 60 °C cell temperature and 1000 mA cm-2 current density. CO coverage is estimated from the gas analysis and CO stripping voltammetry. The cell voltage decrease as a result of 0.2 ppm CO is 29 mV and the CO coverage is 0.6 at the steady state with 0.11 mg cm-2 of anode platinum loading. The CO coverage as a function of CO concentration approximately follows a Temkin-type isotherm. Oxygen permeated to the anode through a membrane is also measured during fuel cell operation. The exhaust velocity of oxygen from the anode was shown to be much higher than the CO supply velocity. Permeated oxygen should play an important role in CO oxidation under low CO concentration conditions.

  1. A New, Scalable and Low Cost Multi-Channel Monitoring System for Polymer Electrolyte Fuel Cells

    Directory of Open Access Journals (Sweden)

    Antonio José Calderón

    2016-03-01

    Full Text Available In this work a new, scalable and low cost multi-channel monitoring system for Polymer Electrolyte Fuel Cells (PEFCs has been designed, constructed and experimentally validated. This developed monitoring system performs non-intrusive voltage measurement of each individual cell of a PEFC stack and it is scalable, in the sense that it is capable to carry out measurements in stacks from 1 to 120 cells (from watts to kilowatts. The developed system comprises two main subsystems: hardware devoted to data acquisition (DAQ and software devoted to real-time monitoring. The DAQ subsystem is based on the low-cost open-source platform Arduino and the real-time monitoring subsystem has been developed using the high-level graphical language NI LabVIEW. Such integration can be considered a novelty in scientific literature for PEFC monitoring systems. An original amplifying and multiplexing board has been designed to increase the Arduino input port availability. Data storage and real-time monitoring have been performed with an easy-to-use interface. Graphical and numerical visualization allows a continuous tracking of cell voltage. Scalability, flexibility, easy-to-use, versatility and low cost are the main features of the proposed approach. The system is described and experimental results are presented. These results demonstrate its suitability to monitor the voltage in a PEFC at cell level.

  2. High-Performance Protonic Ceramic Fuel Cells with Thin-Film Yttrium-Doped Barium Cerate-Zirconate Electrolytes on Compositionally Gradient Anodes.

    Science.gov (United States)

    Bae, Kiho; Lee, Sewook; Jang, Dong Young; Kim, Hyun Joong; Lee, Hunhyeong; Shin, Dongwook; Son, Ji-Won; Shim, Joon Hyung

    2016-04-13

    In this study, we used a compositionally gradient anode functional layer (AFL) consisting of Ni-BaCe0.5Zr0.35Y0.15O3-δ (BCZY) with increasing BCZY contents toward the electrolyte-anode interface for high-performance protonic ceramic fuel cells. It is identified that conventional homogeneous AFLs fail to stably accommodate a thin film of BCZY electrolyte. In contrast, a dense 2 μm thick BCZY electrolyte was successfully deposited onto the proposed gradient AFL with improved adhesion. A fuel cell containing this thin electrolyte showed a promising maximum peak power density of 635 mW cm(-2) at 600 °C, with an open-circuit voltage of over 1 V. Impedance analysis confirmed that minimizing the electrolyte thickness is essential for achieving a high power output, suggesting that the anode structure is important in stably accommodating thin electrolytes. PMID:27029066

  3. Synthesis of yttria-doped zirconia anodes and calcium-doped ceria electrolyte to fuel cell

    International Nuclear Information System (INIS)

    From the pursuit of lower operating temperature of fuel cells solid oxide was used polymeric precursor for the synthesis of reactive powder compositions Zr0,92Y0,08O2 for the anode and Ce0,88Ca0,12O2 for the electrolyte. The solutions were prepared using the metal in much of the composition and citric acid molar ratio of 1:3, under stirring at 60 deg C/1 h. The mixture of metallic citrates was subjected to agitation at a temperature of 80 deg C which was added ethylene glycol in the ratio 60:40 by weight citric acid / ethylene glycol, to form a resin that was pre-calcined at 300 deg C/3 h for to form the expanded resin. The powders were disaggregated in a mortar, screened and calcined at 400, 600 and 800 deg C/2 h. The powders were characterized by standard X-ray diffraction. (author)

  4. Radiation Effects on Platinum Nanostructured Electrocatalysts for Polymer Electrolyte Fuel Cells

    Science.gov (United States)

    Cemmi, A.; Paoletti, C.; Pozio, A.; Baccaro, S.; Giorgi, L.; Serra, E.

    2008-06-01

    Polymer Electrolyte Fuel Cells (PEFCs) offer low weight and high power density and are being considered for automotive and stationary power production besides space and electronic applications. In this work, gamma radiation effects on carbon materials (carbon powder and multiwalled carbon nanotubes) used as substrates in PEFCs electrodes, were studied. The enhancing of free radicals formation (especially on carbon powder) was observed and studied by EPR spectroscopy. This evidence leads to a significant activation of carbon materials because paramagnetic sites represent the preferential position for platinum electrocatalyst nucleation. Galvanostatic techniques were applied to deposits platinum nanoparticles on carbon substrates while FEG-SEM characterization and cyclic voltammetry (CV) were carried out to study the morphology and the electrochemical performances of PEFCs electrodes.

  5. Energy balance affected by electrolyte recirculation and operating modes in microbial fuel cells.

    Science.gov (United States)

    Jacobson, Kyle S; Kelly, Patrick T; He, Zhen

    2015-03-01

    Energy recovery and consumption in a microbial fuel cell (MFC) can be significantly affected by the operating conditions. This study investigated the effects of electrolyte recirculation and operation mode (continuous vs sequence batch reactor) on the energy balance in a tubular MFC. It was found that decreasing the anolyte recirculation also decreased the energy recovery. Because of the open environment of the cathode electrode, the catholyte recirculation consumed 10 to 50 times more energy than the anolyte recirculation, and resulted in negative energy balances despite the reduction of the anolyte recirculation. Reducing the catholyte recirculation to 20% led to a positive energy balance of 0.0288 kWh m(-3). The MFC operated as a sequence batch reactor generated less energy and had a lower energy balance than the one with continuous operation. Those results encourage the further development of MFC technology to achieve neutral or even positive energy output. PMID:25842536

  6. Low stoichiometry operation of a polymer electrolyte membrane fuel cell employing the interdigitated flow field design

    DEFF Research Database (Denmark)

    Berning, Torsten; Odgaard, Madeleine; Kær, Søren Knudsen

    2011-01-01

    Fuel cell operation on dry reactant gases under low stoichiometry conditions employing the interdigitated flow field is investigated using a multi-fluid model. It is assumed that the MEA contains a water uptake layer which facilitates water absorption to the membrane and hence prevents the anode...... gas phase from drying out. It is shown that the membrane humidity increases with decreasing stoichiometric flow ratios to values of λ ≈ 7. Operating the cathode side at a stoichiometric flow ratio of 1.2 appears feasible under steady state conditions, while our simulations suggest that the anode...... stoichiometry may even be as low as 1.05. The effect of operation pressure and temperature on the membrane water content is studied. Finally, experiments are suggested to determine the kinetic absorption coefficient and the specific surface area of the electrolyte inside the catalyst layers....

  7. Partially Perfluorinated Hydrocarbon Ionomer for Cathode Catalyst Layer of Polymer Electrolyte Membrane Fuel Cell

    International Nuclear Information System (INIS)

    Hydrocarbon ionomers have not been successfully employed in the cathode of polymer electrolyte fuel cell (PEFC)s due to their low oxygen permeabilities. In this work, we propose a partially fluorinated aromatic polyether with sulfonic acid groups (s-PFPE) as an ionomer for the cathode catalyst layer. Compared to sulfonated poly(ether ether ketone) (s-PEEK), it exhibited more than 1.5 times higher oxygen permeability at RH 40% and 1.3 times higher at RH 100%. The catalyst layer based on s-PFPE showed higher power performance than that based on s-PEEK owing to enhanced oxygen transport and fast proton conduction through the s-PFPE ionomer phase covering the catalyst layer. We demonstrate that the introduction of the perfluorinated moieties to the hydrocarbon backbone is an effective strategy for the use of hydrocarbon ionomer in the cathode of PEMFCs

  8. The thermal stability of sodium beta'-Alumina solid electrolyte ceramic in AMTEC cells

    International Nuclear Information System (INIS)

    A critical component of alkali metal thermal-to electric converter (AMTEC) devices for long duration space missions is the beta'-alumina solid electrolyte ceramic (BASE), for which there exists no substitute. The temperature and environmental conditions under which BASE remains stable control operational parameters of AMTEC devices. We have used mass loss experiments in vacuum to 1573K to characterize the kinetics of BASE decomposition, and conductivity and exchange current measurements in sodium vapor filled exposure cells to 1223K to investigate changes in the BASE which affect its ionic conductivity. There is no clear evidence of direct thermal decomposition of BASE below 1273K, although limited soda loss may occur. Reactive metals such as Mn or Cr can react with BASE at temperatures at least as low as 1223K

  9. Performance of diagonal control structures at different operating conditions for polymer electrolyte membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Serra, Maria; Husar, Attila; Feroldi, Diego; Riera, Jordi [Institut de Robotica i Informatica Industrial, Universitat Politecnica de Catalunya, Consejo Superior de Investigaciones Cientificas, C. Llorens i Artigas 4, 08028 Barcelona (Spain)

    2006-08-25

    This work is focused on the selection of operating conditions in polymer electrolyte membrane fuel cells. It analyses efficiency and controllability aspects, which change from one operating point to another. Specifically, several operating points that deliver the same amount of net power are compared, and the comparison is done at different net power levels. The study is based on a complex non-linear model, which has been linearised at the selected operating points. Different linear analysis tools are applied to the linear models and results show important controllability differences between operating points. The performance of diagonal control structures with PI controllers at different operating points is also studied. A method for the tuning of the controllers is proposed and applied. The behaviour of the controlled system is simulated with the non-linear model. Conclusions indicate a possible trade-off between controllability and optimisation of hydrogen consumption. (author)

  10. Impact of Electrolytes Based on Different Solvents on the Long Term Stability of Dye Sensitized Solar Cells

    International Nuclear Information System (INIS)

    Highlights: •Aging studies were carried out under heat (60 °C) and illumination with DSSCs. •DSSCs with MPN, PC and GBL showed decrease in performance over 60 days. •With NMP, increase in JSC and efficiency was observed whereas VOC decreased. •Leaching of Zn2+ from sealant and desorption of NMP from TiO2 are possible causes. -- Abstract: The present article demonstrates the effect of different solvents used in the preparation of electrolyte on the photoelectrochemical characteristics of dye sensitized solar cells (DSSCs) aged under heat (60 °C) and illumination for 60 days. The study has been carried out with four different solvents: 3-methoxypropionitrile (MPN), N-methyl-2-pyrrolidone (NMP), propylene carbonate (PC) and γ-butyrolactone (GBL) which differ in terms of donor number, viscosity and dielectric constant. For DSSCs with electrolytes based on MPN, PC and GBL as solvents, performance decreases with time. In contrast, for DSSC with NMP as solvent in electrolyte, increase in JSC and hence, efficiency up to 15 days has been observed followed by a gradual decrease, but remaining above its initial value after 60 days. However, VOC of such cell decreases with time. There are two possible causes for the above observations. Desorption of NMP molecules from titania surface occurred with aging. Secondly, zinc ions leached into the electrolyte following reaction of NMP with sealant were adsorbed on titania surface. The causes behind aging behavior of cells prepared with different solvent based electrolytes have been analyzed using electrochemical impedance analysis of DSSCs, energy-dispersive X-ray spectroscopy (EDS) of photoanodes and inductively coupled plasma-atomic emission spectroscopy (ICP-AES) of electrolyte containing sealant sample which had also undergone aging under similar condition

  11. Standard Gibbs energy of formation of LaNiO3 using a calcium fluoride solid electrolyte galvanic cell

    International Nuclear Information System (INIS)

    In the present work a CaF2 solid electrolyte galvanic cell has been employed to determine the Gibbs energy of formation of LaNiO3 from the component oxides in the temperature range 1140-1273 K. (author). 4 ref., 1 fig

  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. An efficient binary ionic liquid based quasi solid-state electrolyte for dye-sensitized solar cells

    International Nuclear Information System (INIS)

    A novel binary ionic liquid electrolyte containing lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) and binary ionic liquids, which is composed of 1-butyl-3-methylimidazolium iodide (BMII) and 1-butyl-3-methylimidazolium thiocyanate (BMISCN), is developed for dye-sensitized solar cells (DSSCs). It is found that incorporation of LiTFSI as charge transfer promoter with BMII has positive effect on the interfacial charge transfer of the dye/TiO2 film, further addition of BMISCN into the above composite electrolyte can take advantage of its low viscosity to enhance the ionic conductivity and reduce the interfacial charge transfer resistance, and a photovoltaic conversion efficiency of 5.55% is obtained from the solar cell fabricated with the optimized binary ionic liquid electrolyte without iodine participation under AM 1.5 illumination at 100 mW cm−2, with a 108.6% improvement in the efficiency with lower resistance and higher ionic conductivity as compared to the solar cell fabricated with single BMII ionic liquid-based electrolyte. The above results should be attributed to the reduced charge recombination and the effective interfacial charge transfer in the solar cell

  14. Anode-supported ScSZ-electrolyte SOFC with whole cell materials from combined EDTA-citrate complexing synthesis process

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Hongxia; Ran, Ran; Zhou, Wei; Shao, Zongping [State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology, No. 5 Xing Mofan Road, Nanjing, JiangSu 210009 (China)

    2007-10-25

    The potential application of combined EDTA-citrate complexing process (ECCP) in intermediate-temperature solid-oxide fuel cells (IT-SOFCs) processing was investigated. ECCP-derived scandia-stabilized-zirconia (ScSZ) powder displayed low packing density, high surface area and nano-crystalline, which was ideal material for thin-film electrolyte fabrication based on dual dry pressing. A co-synthesis of NiO + ScSZ anode based on ECCP was developed, which showed reduced NiO(Ni) and ScSZ grain sizes and improved homogeneity of the particle size distribution, as compared with the mechanically mixed NiO + ScSZ anode. Anode-supported ScSZ electrolyte fuel cell with the whole cell materials synthesized from ECCP was successfully prepared. The porous anode and cathode exhibited excellent adhesion to the electrolyte layer. Fuel cell with 30 {mu}m thick ScSZ electrolyte and La{sub 0.8}Sr{sub 0.2}MnO{sub 3} cathode showed a promising maximum peak power density of 350 mW cm{sup -2} at 800 C. (author)

  15. Control and experimental characterization of a methanol reformer for a 350W high temperature polymer electrolyte membrane fuel cell system

    DEFF Research Database (Denmark)

    Andreasen, Søren Juhl; Kær, Søren Knudsen; Jensen, Hans-Christian Becker; Sahlin, Simon Lennart

    High temperature polymer electrolyte membrane(HTPEM) fuel cells offer many advantages due to their increased operating tempera-tures compared to similar Nafion-based membrane tech-nologies, that rely on the conductive abilities of liquid water. The polybenzimidazole (PBI) membranes are especially...

  16. Materials, design, and modeling for bipolar/end plates in polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Kumar, Atul

    New vehicle technologies are required to improve upon conventional internal combustion engine technologies. In this regard, the development of fuel cell (polymer electrolyte membrane type) vehicles with improved efficiency and reliability seems promising. However, some technical issues exist that hinder the commercialization of this technology. One such issue is the high cost, volume, and mass of the bipolar/end plates in the polymer electrolyte membrane fuel cell (PEMFC) stack. This research, therefore, focuses on materials, design, and modeling for bipolar/end plates in PEMFC stack. Alternative materials were tested that can replace the conventionally used graphite in the PEMFC stack. With regards to these, a two-cell PEMFC stack was fabricated with SS-316 multi-parallel flow-field (MPFF) designed bipolar/end plates. The stack was run for over 1000 hours and showed no appreciable drop in performance. To enhance the understanding and for determining the effect of operating parameters in PEMFC, a single cell model was developed. The model results agree well with the experimental data. The gas flow-field in bipolar/end plates of the PEMFC was optimized with respect to channel dimensions, channel shape, flow-field design, and flow-field permeability. It was seen that lower the flow-field permeability better is the fuel cell performance. Based on this, the concept of use of metal foams in the gas flow-field was proposed. Experiments were carried out to test the feasibility of metal foams in the gas flow-field of bipolar/end plates in PEMFC stack. Three different porous materials, viz. Ni-Cr metal foam (50 P PI, pores per inch), S S-316 metal foam (20 PPI), and carbon cloth were tested, and the results were compared to the conventional MPFF channel design concept. It was seen that the performance with Ni-Cr metal foam was highest, and decreased in the order of SS-316 metal foam, conventional MPFF design, and carbon cloth. This trend was explained based on the effective

  17. Control and experimental characterization of a methanol reformer for a 350 W high temperature polymer electrolyte membrane fuel cell system

    DEFF Research Database (Denmark)

    Andreasen, Søren Juhl; Kær, Søren Knudsen; Sahlin, Simon Lennart

    2013-01-01

    This work presents a control strategy for controlling the methanol reformer temperature of a 350 W high temperature polymer electrolyte membrane fuel cell system, by using a cascade control structure for reliable system operation. The primary states affecting the methanol catalyst bed temperature...... is the water and methanol mixture fuel flow and the burner fuel/air ratio and combined flow. An experimental setup is presented capable of testing the methanol reformer used in the Serenergy H3 350 Mobile Battery Charger; a high temperature polymer electrolyte membrane (HTPEM) fuel cell system. The...... experimental system consists of a fuel evaporator utilizing the high temperature waste gas from the cathode air cooled 45 cell HTPEM fuel cell stack. The fuel cells used are BASF P1000 MEAs which use phosphoric acid doped polybenzimidazole membranes. The resulting reformate gas output of the reformer system is...

  18. A novel glowing electrolyte based on perylene accompany with spectrum compensation function for efficient dye sensitized solar cells

    Science.gov (United States)

    Bai, Sihang; Liang, Liangliang; Wang, Changlei; Mehnane, Hadja Fatima; Bu, Chenghao; You, Sujian; Yu, Zhenhua; Cheng, Nian; Hu, Hao; Liu, Wei; Guo, Shishang; Zhao, Xingzhong

    2015-04-01

    Liquid electrolytes employing fluorescent perylene are prepared and applied in dye sensitized solar cells (DSSCs). Due to the excellent down-shifting property of perylene, photons with short wavelength (from about 350 to 440 nm) can be absorbed and then converted to ones with longer wavelength (from 450 nm to 550 nm) which can be more efficiently utilized by DSSCs. As a result, device with optimal concentration of 0.05 M perylene presents an efficient improvement in the short-circuit current density (Jsc), leading to an increase of 11.6% in the power conversion efficiency (PCE) compared with the reference DSSC based on control electrolyte.

  19. Improved Composite Gel Electrolyte by Layered Vermiculite for Quasi-Solid-State Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Hongcai He

    2014-01-01

    Full Text Available A composite quasisolid electrolyte is prepared by adding a layered vermiculite (VMT into the iodide/triiodide electrolyte including 4-tert-butylpyridine, which obviously improves the photovoltaic properties of quasisolid dye-sensitized solar cells (DSSCs. When adding 6 wt% VMT, the maximum photovoltaic conversion efficiency of 3.89% is obtained, which reaches more than two times greater than that without VMT. This enhancement effect is primarily explained by studying the Nyquist spectra, dark currents, and photovoltaic conversion efficiency.

  20. A high-performance supercapacitor cell based on ZIF-8-derived nanoporous carbon using an organic electrolyte.

    Science.gov (United States)

    Salunkhe, Rahul R; Young, Christine; Tang, Jing; Takei, Toshiaki; Ide, Yusuke; Kobayashi, Naoya; Yamauchi, Yusuke

    2016-04-01

    Low-cost supercapacitors have the ability to rapidly store a large amount of charge, which makes them the best alternative to batteries in portable electronics. Here, we demonstrate the fabrication of all-carbon supercapacitors using an organic electrolyte. By using ZIF-derived nanoporous carbon electrodes, we have realized a high-performance supercapacitor cell using 2 M NEt4BF4/PC as the electrolyte. Our device shows good energy storage capacity that is comparable to the other previously reported supercapacitors. PMID:26928244

  1. Stabilized γ-BIMNVOX solid electrolyte: Ethylene glycol–citrate sol–gel synthesis, microwave-assisted calcination, and structural and electrical characterization

    Energy Technology Data Exchange (ETDEWEB)

    Al-Areqi, Niyazi A.S., E-mail: niyazi.alareqi@gmail.com [Department of Chemistry, Faculty of Applied Science, Taiz University, Taiz, Republic of Yemen (Yemen); Beg, Saba [Department of Chemistry, Aligarh Muslim University, Aligarh 202002 (India); Al-Alas, Ahlam [Department of Chemistry, Faculty of Applied Science, Taiz University, Taiz, Republic of Yemen (Yemen); Hafeez, Shehla [Department of Chemistry, Aligarh Muslim University, Aligarh 202002 (India)

    2013-12-25

    Highlights: •γ-BIMNVOX was synthesized by ethylene glycol–citrate sol–gel route. •γ-BIMNVOX crystallizes by 25-min microwave-assisted calcination. •Smaller particle sizes for microwave calcined BIMNVOX samples. •Best oxide-ion performance for microwave calcined BIMNVOX samples. -- Abstract: Samples of γ-BIMNVOX (Bi{sub 2}V{sub 1−x}Mn{sub x}O{sub 5.5−x/2}; 0.13 ⩽ x ⩽ 0.20) system were synthesized by an ethylene glycol–citrate sol–gel route. The resulting xerogels were then calcined by the microwave heating using a modified domestic microwave oven operated at 2.45 GHz. Microwave-assisted calcination samples in comparison with other conventionally calcined samples were characterized in terms of phase crystallization, stabilization and particle size using simultaneous thermogravimetric–differential thermal analysis (TG–DTA), X-ray powder diffraction (XRPD) and scanning electron microscopy (SEM). The AC impedance spectroscopy was employed for electrical characterization. It was found that the microwave-assisted calcination route successfully produces better crystalline stabilized γ-BIMNVOX samples with appreciably small average particle sizes after only 25 min of microwave heating. The electrical properties of microwave calcined γ-BIMNVOX system make it an advanced low-temperature solid electrolyte suitable for use in oxide-ion based electrochemical applications.

  2. Lithium iodide effect on the electrochemical behavior of agarose based polymer electrolyte for dye-sensitized solar cell

    International Nuclear Information System (INIS)

    Highlights: · Conduction behavior in agarose electrolyte system. · Charge recombination resistance is reduced with the increasing LiI concentration. · Charge transfer resistance is also reduced with the increasing LiI concentration. · Electron lifetime is shortened by increasing LiI concentrations. · LiI addition enhances the back reaction in DSSC. - Abstract: The effect of lithium iodide (LiI: 0-85 wt%) on the electrochemical behavior of agarose-based polymer electrolytes for dye-sensitized solar cells (DSSC) was investigated. Fourier Transform Infrared Spectroscopy (FTIR) and scanning electronic microscopy (SEM) were employed to characterize the interactions between polymer matrix and salt and the morphology of the agarose electrolytes, respectively. From the AC impedance spectra study, it was determined that the conduction behavior of the agarose-based polymer electrolyte matches the 'salt-in-polymer' like behavior of low LiI content (0-25 wt%) and 'polymer-in-salt' like behavior of high LiI content (25-85 wt%). Detailed analysis of characteristic electrochemical processes occurring in DSSC with these agarose electrolytes was also obtained by employing the EIS technique. The impedance spectra showed that the electron lifetime of DSSC was shortened with increasing LiI concentration, while the charge transfer resistance and charge recombination resistance were reduced when LiI concentration was increased.

  3. Transparent bifacial dye-sensitized solar cells based on organic counter electrodes and iodine-free electrolyte

    Science.gov (United States)

    Ku, Zhiliang; Rong, Yaoguang; Han, Hongwei

    2013-10-01

    In this study, a novel bifacially active transparent dye-sensitized solar cell (DSSCs) assembled with a transparent poly(3,4-ethylenedioxythiophene) (PEDOT) counter electrode and a colorless iodine-free polymer gel (IFPG) electrolyte was developed. The IFPG electrolyte was prepared by employing an ionic liquid (1,2-dimethyl-3-propylinmidazolium iodide, DMPII) as the charge transfer intermediate and a polymer composite as the gelator without the addition of iodine, exhibiting high conductivity and non-absorption characters. PEDOT electrodes were prepared via a facile electro-polymerization method. By controlling the amount of polymerization charge capacity, we optimized the PEDOT electrodes with high transparency and a favorable activity for catalyzing the IFPG electrolyte. The bifacial DSSCs device fabricated by this kind of transparent PEDOT electrode and colorless IFPG electrolyte showed a power conversion efficiency (PCE) of 6.35% and 4.98% at 100 mW cm-2 AM1.5 illumination corresponding to front- and rear-side illumination. It is notable that the PCE under rear-side illumination approaches 80% that of front-side illumination. Moreover, the device shows excellent stability as confirmed by aging test. These promising results highlight the enormous potential of this transparent PEDOT CE and colorless IFPG electrolyte in scaling up and commercialization of low cost and effective bifacial DSSCs.

  4. One-dimensional steady state algebraic model on the passive direct methanol fuel cell with consideration of the intermediate liquid electrolyte

    Science.gov (United States)

    Yin, Ken-Ming

    2015-05-01

    One-dimensional steady state performance equations of passive direct methanol fuel cell are formulated at the presence of intermediate liquid electrolyte. This model evaluates the effect of liquid electrolyte on the cell polarization curve in detail. It is shown that liquid electrolyte employed reduce the methanol crossover rate, increase the fuel utilization, and decrease the cathode voltage loss. The prediction shows that ohmic potential drop is significant at high polarization if low methanol concentration is fed. Cell is better performed without liquid electrolyte. On the other hand, the cathode voltage loss by the mixed potential is more influential at high methanol concentration. Thus, liquid electrolyte reduces the cathode over-potential, and cell performs better with the liquid film.

  5. Development of a polymer electrolyte membrane fuel cell stack for an underwater vehicle

    Science.gov (United States)

    Han, In-Su; Kho, Back-Kyun; Cho, Sungbaek

    2016-02-01

    This paper presents a polymer electrolyte membrane (PEM) fuel cell stack that is specifically designed for the propulsion of an underwater vehicle (UV). The stack for a UV must be continuously operated in a closed space using hydrogen and pure oxygen; it should meet various performance requirements such as high hydrogen and oxygen utilizations, low hydrogen and oxygen consumptions, a high ramp-up rate, and a long lifetime. To this end, a cascade-type stack design is employed and the cell components, including the membrane electrode assembly and bipolar plate, are evaluated using long-term performance tests. The feasibility of a fabricated 4-kW-class stack was confirmed through various performance evaluations. The proposed cascade-type stack exhibited a high efficiency of 65% and high hydrogen and oxygen utilizations of 99.89% and 99.68%, respectively, resulting in significantly lesser purge-gas emissions to the outside of the stack. The load-following test was successfully performed at a high ramp-up rate. The lifetime of the stack was confirmed by a 3500-h performance test, from which the degradation rate of the cell voltage was obtained. The advantages of the cascade-type stack were also confirmed by comparing its performance with that of a single-stage stack operating in dead-end mode.

  6. Metal foams application to enhance cooling of open cathode polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Sajid Hossain, Mohammad; Shabani, Bahman

    2015-11-01

    Conventional channel flow fields of open cathode Polymer Electrolyte Membrane Fuel Cells (PEMFCs) introduce some challenges linked to humidity, temperature, pressure and oxygen concentration gradients along the conventional flow fields that reduce the cell performance. According to previous experimental reports, with conventional air flow fields, hotspot formation due to water accumulation in Gas Diffusion Layer (GDL) is common. Unlike continuous long flow passages in conventional channels, metal foams provide randomly interrupted flow passages. Re-circulation of fluid, due to randomly distributed tortuous ligaments, enhances temperature and humidity uniformity in the fluid. Moreover, the higher electrical conductivity of metal foams compared to non-metal current collectors and their very low mass density compared to solid metal materials are expected to increase the electrical performance of the cell while significantly reducing its weight. This article reviews the existing cooling systems and identifies the important parameters on the basis of reported literature in the air cooling systems of PEMFCs. This is followed by investigating metal foams as a possible option to be used within the structure of such PEMFCs as an option that can potentially address cooling and flow distribution challenges associated with using conventional flow channels, especially in air-cooled PEMFCs.

  7. CoPd x oxygen reduction electrocatalysts for polymer electrolyte membrane and direct methanol fuel cells

    International Nuclear Information System (INIS)

    The electrochemical activity of carbon-supported cobalt-palladium alloy electrocatalysts of various compositions have been investigated for the oxygen reduction reaction in a 5 cm2 single cell polymer electrolyte membrane fuel cell. The polarization experiments have been conducted at various temperatures between 30 and 60 deg. C and the reduction performance compared with data from a commercial Pt catalyst under identical conditions. Investigation of the catalytic activity of the CoPd x PEMFC system with varying composition reveals that a nominal cobalt-palladium atomic ratio of 1:3, CoPd3, exhibits the best performance of all studied catalysts, exhibiting a catalytic activity comparable to the commercial Pt catalyst. The ORR on CoPd3 has a low activation energy, 52 kJ/mol, and a Tafel slope of approximately 60 mV/decade, indicating that the rate-determining step is a chemical step following the first electron transfer step and may involve the breaking of the oxygen bond. The CoPd3 catalyst also exhibits excellent chemical stability, with the open circuit cell voltage decreasing by only 3% and the observed current decreasing by only 10% at 0.8 V over 25 h. The CoPd3 catalyst also exhibits superior tolerance to methanol crossover poisoning than Pt

  8. Liquid water transport characteristics of porous diffusion media in polymer electrolyte membrane fuel cells: A review

    Science.gov (United States)

    Liu, Xunliang; Peng, Fangyuan; Lou, Guofeng; Wen, Zhi

    2015-12-01

    Fundamental understanding of liquid water transport in gas diffusion media (GDM) is important to improve the material and structure design of polymer electrolyte membrane (PEM) fuel cells. Continuum methods of two-phase flow modeling facilitate to give more details of relevant information. The proper empirical correlations of liquid water transport properties, such as capillary characteristics, water relative permeability and effective contact angle, are crucial to two phase flow modeling and cell performance prediction. In this work, researches on these properties in the last decade are reviewed. Various efforts have been devoted to determine the water transport properties for GDMs. However, most of the experimental studies are ex-situ measurements. In-situ measurements for GDMs and extending techniques available to study the catalyst layer and the microporous layer will be further challenges. Using the Leverett-Udell correlation is not recommended for quantitative modeling. The reliable Leverett-type correlation for GDMs, with the inclusion of the cosine of effective contact angle, is desirable but hard to be established for modeling two-phase flow in GDMs. A comprehensive data set of liquid water transport properties is needed for various GDM materials under different PEM fuel cell operating conditions.

  9. Effect of catalyst layer defects on local membrane degradation in polymer electrolyte fuel cells

    Science.gov (United States)

    Tavassoli, Arash; Lim, Chan; Kolodziej, Joanna; Lauritzen, Michael; Knights, Shanna; Wang, G. Gary; Kjeang, Erik

    2016-08-01

    Aiming at durability issues of fuel cells, this research is dedicated to a novel experimental approach in the analysis of local membrane degradation phenomena in polymer electrolyte fuel cells, shedding light on the potential effects of manufacturing imperfections on this process. With a comprehensive review on historical failure analysis data from field operated fuel cells, local sources of iron oxide contaminants, catalyst layer cracks, and catalyst layer delamination are considered as potential candidates for initiating or accelerating the local membrane degradation phenomena. Customized membrane electrode assemblies with artificial defects are designed, fabricated, and subjected to membrane accelerated stress tests followed by extensive post-mortem analysis. The results reveal a significant accelerating effect of iron oxide contamination on the global chemical degradation of the membrane, but dismiss local traces of iron oxide as a potential stressor for local membrane degradation. Anode and cathode catalyst layer cracks are observed to have negligible impact on the membrane degradation phenomena. Notably however, distinct evidence is found that anode catalyst layer delamination can accelerate local membrane thinning, while cathode delamination has no apparent effect. Moreover, a substantial mitigating effect for platinum residuals on the site of delamination is observed.

  10. Investigation of degradation effects in polymer electrolyte fuel cells under automotive-related operating conditions

    Science.gov (United States)

    Enz, S.; Dao, T. A.; Messerschmidt, M.; Scholta, J.

    2015-01-01

    The influence of artificial starvation effects during automotive-related operating conditions is investigated within a polymer electrolyte fuel cell (PEFC) using non-dispersive infrared sensors and a current scan shunt. Driving cycles (DC) and single load change experiments are performed with specific fuel and oxidant starvation conditions. Within the DC experiments, a maximal CO2 amount of 4.67 μmol per cycle is detected in the cathode and 0.97 μmol per cycle in the anode exhaust without reaching fuel starvation conditions during the DC. Massive cell reversal conditions occur within the single load change experiments as a result of anodic fuel starvation. As soon as a fuel starvation appears, the emitted CO2 increases exponentially in the anode and cathode exhaust. A maximal CO2 amount of 143.8 μmol CO2 on the anode side and 5.8 μmol CO2 on the cathode side is detected in the exhaust gases. The critical cell reversal conditions only occur by using hydrogen reformate as anode reactant. The influence of the starvation effects on the PEFC performance is investigated via polarization curves, cyclic and linear sweep voltammetry as well as electrochemical impedance spectroscopy. The PEFC performance is reduced by 47% as a consequence of the dynamic operation.

  11. Numerical evaluation of crack growth in polymer electrolyte fuel cell membranes based on plastically dissipated energy

    Science.gov (United States)

    Ding, Guoliang; Santare, Michael H.; Karlsson, Anette M.; Kusoglu, Ahmet

    2016-06-01

    Understanding the mechanisms of growth of defects in polymer electrolyte membrane (PEM) fuel cells is essential for improving cell longevity. Characterizing the crack growth in PEM fuel cell membrane under relative humidity (RH) cycling is an important step towards establishing strategies essential for developing more durable membrane electrode assemblies (MEA). In this study, a crack propagation criterion based on plastically dissipated energy is investigated numerically. The accumulation of plastically dissipated energy under cyclical RH loading ahead of the crack tip is calculated and compared to a critical value, presumed to be a material parameter. Once the accumulation reaches the critical value, the crack propagates via a node release algorithm. From the literature, it is well established experimentally that membranes reinforced with expanded polytetrafluoroethylene (ePTFE) reinforced perfluorosulfonic acid (PFSA) have better durability than unreinforced membranes, and through-thickness cracks are generally found under the flow channel regions but not land regions in unreinforced PFSA membranes. We show that the proposed plastically dissipated energy criterion captures these experimental observations and provides a framework for investigating failure mechanisms in ionomer membranes subjected to similar environmental loads.

  12. Investigation of gas concentration cell based on LiSiPO electrolyte and Li2CO3, Au electrode

    Institute of Scientific and Technical Information of China (English)

    ZHU YongMing; CHU WingFong; WEPPNER Werner

    2009-01-01

    Solid lithium ion conducting electrochemical cells using LiSiPO as solid electrolyte and Li2CO3 mixed with Au as electrodes were prepared and employed as chemical sensors for the detection of CO2 gas.The EMF of the cell depends on the concentration of CO2 in air according to the partial pressure de-pendence of Nernst's law in the investigated range from 100 to 2000 ppm over the temperature range from 473 K to 673 K.

  13. Multilayer graphene for long-term corrosion protection of stainless steel bipolar plates for polymer electrolyte membrane fuel cell

    DEFF Research Database (Denmark)

    Stoot, Adam Carsten; Camilli, Luca; Spiegelhauer, Susie Ann;

    2015-01-01

    Abstract Motivated by similar investigations recently published (Pu et al., 2015), we report a comparative corrosion study of three sets of samples relevant as bipolar plates for polymer electrolyte fuel cells: stainless steel, stainless steel with a nickel seed layer (Ni/SS) and stainless steel...... graphene film is still intact with unchanged defect density. Our results show that even non-perfect multilayer graphene films can considerably increase the lifetime of future-generation bipolar plates for fuel cells....

  14. Synthesis and ceramic processing of zirconia alumina composites for application as solid oxide fuel cell electrolytes

    International Nuclear Information System (INIS)

    The global warmness and the necessity to obtain clean energy from alternative methods than petroleum raises the importance of developing cleaner and more efficient systems of energy generation, among then, the solid oxide fuel cell (SOFC). Cubic stabilized zirconia (CSZ) has been the most studied material as electrolyte in SOFC, due to its ionic conductivity and great stability at operation conditions. However, its low fracture toughness difficulties its application as a thin layer, what could lead to an improvement of cell efficiency. In this sense, the alumina addition in CSZ forms a composite, which can shift its mechanical properties, without compromising its electrical properties. In this work, coprecipitation synthesis route and ceramic processing of zirconia-alumina composites were studied, in order to establish optimum conditions to attain high density, homogeneous microstructure, and better mechanical properties than CSZ, without compromising ionic conductivity. For this purpose, composites containing up to 40 wt % of alumina, in a 9 mol % yttria-stabilized zirconia (9Y-CSZ) matrix were evaluated. In order to optimize the synthesis of the composites, a preliminary study of powder obtaining and processing were carried out, at compositions containing 20 wt % of alumina, in 9Y-CSZ. The ceramic powders were characterized by helium picnometry, X-ray diffraction, scanning electronic microscopy, transmission electronic microscopy, thermogravimetry, differential scanning calorimetry, granulometry by laser diffraction and gas adsorption (BET). The characterization of sinterized compacts were performed by X-ray diffraction, scanning electron microscopy, optical microscopy, density measurements, Vickers indentation and impedance spectroscopy. The obtained results show that the alumina addition, in the 9Y-CSZ matrix powders, raises the specific surface area, promotes deagglomeration of powders and elevates the oxides crystallization temperature, requiring higher

  15. Balance between the physical diffusion and the exchange reaction on binary ionic liquid electrolyte for dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Feng; Lin, Hong; Zhang, Jing [State Key Laboratory of New Ceramics and Fine Processing, Department of Material Science and Engineering, Tsinghua University, Beijing 100084 (China); Li, Jianbao [State Key Laboratory of New Ceramics and Fine Processing, Department of Material Science and Engineering, Tsinghua University, Beijing 100084 (China); Key Laboratory of Ministry of Education for Application Technology of Chemical Materials in Hainan Superior Resources, Hainan Provincial Key Laboratory of Research on Utilization of Si-Zr-Ti Resources, College of Materials Science and Chemical Engineering, Hainan University, Haikou 570228 (China)

    2011-02-01

    A comprehensive characterizations of viscosities, conductivities, triiodide diffusion coefficients, charge-transfer resistances and photovoltaic performance of a potential dye-sensitized solar cell (DSC) electrolyte systems based on binary ionic liquid (IL) mixtures, namely, 1-ethyl-3-methylimidazolium dicyanamide (EMIDCA)/1-methyl-3-propylimidazolium iodide (PMII) with a fixed iodine concentration at varying EMIDCA volume fraction are investigated in the present study. Viscosity and conductivity values are accurately correlated with regard to temperature and EMIDCA volume fraction. The triiodide diffusion coefficients, the predominant electrolyte parameter for limitation of DSC efficiency, are determined by symmetrical cell methods. The physical diffusion and exchange reactions between the iodide and triiodide dominate the apparent triiodide diffusion coefficients at different range of EMIDCA volume fraction. A balance between the viscosity-dependent physical diffusion and the exchange reactions can get at an optimal volume percents of EMIDCA. Impedance spectroscopy and photovoltaic results both support the existence of an optimized binary IL electrolyte composition. Hence, for optimizing an IL-based electrolyte in regards to triiodide transport, a low viscosity is not the exclusive crucial factor since exchange reactions transport effects also play an important role to resolve the diffusion limitation of DSC efficiency. (author)

  16. Balance between the physical diffusion and the exchange reaction on binary ionic liquid electrolyte for dye-sensitized solar cells

    Science.gov (United States)

    Hao, Feng; Lin, Hong; Zhang, Jing; Li, Jianbao

    A comprehensive characterizations of viscosities, conductivities, triiodide diffusion coefficients, charge-transfer resistances and photovoltaic performance of a potential dye-sensitized solar cell (DSC) electrolyte systems based on binary ionic liquid (IL) mixtures, namely, 1-ethyl-3-methylimidazolium dicyanamide (EMIDCA)/1-methyl-3-propylimidazolium iodide (PMII) with a fixed iodine concentration at varying EMIDCA volume fraction are investigated in the present study. Viscosity and conductivity values are accurately correlated with regard to temperature and EMIDCA volume fraction. The triiodide diffusion coefficients, the predominant electrolyte parameter for limitation of DSC efficiency, are determined by symmetrical cell methods. The physical diffusion and exchange reactions between the iodide and triiodide dominate the apparent triiodide diffusion coefficients at different range of EMIDCA volume fraction. A balance between the viscosity-dependent physical diffusion and the exchange reactions can get at an optimal volume percents of EMIDCA. Impedance spectroscopy and photovoltaic results both support the existence of an optimized binary IL electrolyte composition. Hence, for optimizing an IL-based electrolyte in regards to triiodide transport, a low viscosity is not the exclusive crucial factor since exchange reactions transport effects also play an important role to resolve the diffusion limitation of DSC efficiency.

  17. Biodegradation test of SPS-LS blends as polymer electrolyte membrane fuel cells

    International Nuclear Information System (INIS)

    Sulfonated polystyrene (SPS) can be applied as a proton exchange membrane fuel cell due to its fairly good chemical stability. In order to be applied as polymer electrolyte membrane fuel cells (PEMFCs), membrane polymer should have a good ionic conductivity, high proton conductivity, and high mechanical strength. Lignosulfonate (LS) is a complex biopolymer which has crosslinks and sulfonate groups. SPS-LS blends with addition of SiO2 are used to increase the proton conductivity and to improve the mechanical properties and thermal stability. However, the biodegradation test of SPS-LS blends is required to determine whether the application of these membranes to be applied as an environmentally friendly membrane. In this study, had been done the synthesis of SPS, biodegradability test of SPS-LS blends with variations of LS and SiO2 compositions. The biodegradation test was carried out in solid medium of Luria Bertani (LB) with an activated sludge used as a source of microorganism at incubation temperature of 37°C. Based on the results obtained indicated that SPS-LS-SiO2 blends are more decomposed by microorganism than SPS-LS blends. This result is supported by analysis of weight reduction percentage, functional groups with Fourier Transform Infrared (FTIR) Spectroscopy, and morphological surface with Scanning Electron Microscopy (SEM)

  18. 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)

  19. A review of electrocatalysts with enhanced CO tolerance and stability for polymer electrolyte membarane fuel cells

    International Nuclear Information System (INIS)

    A comprehensive review of the investigations performed in search for development of electrocatalysts with enhanced reformate tolerance for low temperature polymer electrolyte membrane (PEM) fuel cells are presented. Remarkable efforts have been made to attain improved catalytic activities and robustness by adding second element to Pt/C or third element to Pt–Ru/C, commercial catalysts for PEM fuel cell applications. The enhanced CO tolerance of the developed catalysts is strongly dependent on the type, composition and atomic ratios of the added elements/groups, and type and structure of the support materials. The synthesis method of the catalysts also plays a remarkable role in the catalytic activity and stability since it determines the structure, morphology and size distribution of the catalyst nanoparticles, which are directly effective on the stability and activity. Choosing a proper synthesis method, inclusion of appropriate content of suitable promoters to Pt-based catalysts, and using a proper support material are the major requirements of an effective catalyst. The CO tolerance enhancement has been attributed to the bi-functional mechanism and electronic effects. Understanding the underlying mechanisms and the activity–structure correlations will shed a light in designing novel electrocatalysts via innovative routes for excellent robust CO tolerant electrocatalysts

  20. Degradation of polymer electrolyte membrane fuel cell by siloxane in biogas

    Science.gov (United States)

    Seo, Ji-Sung; Kim, Da-Yeong; Hwang, Sun-Mi; Seo, Min Ho; Seo, Dong-Jun; Yang, Seung Yong; Han, Chan Hui; Jung, Yong-Min; Guim, Hwanuk; Nahm, Kee Suk; Yoon, Young-Gi; Kim, Tae-Young

    2016-06-01

    We studied the degradation and durability of polymer electrolyte membrane fuel cell (PEMFC) at membrane-electrode-assembly (MEA) level by injection of octamethylcyclotetrasiloxane (D4) as a representative siloxane, which has been found in many industrial and personal products. Specifically, i) GC/MS analysis demonstrated that the ring-opening polymerization of D4 could result in the formation of various linear and cyclic siloxanes in both electrodes of MEA; ii) post-test analysis revealed that the transformed siloxanes were transported from the anode to the cathode via free-volumes in the polymer membrane; iii) RDE measurement and DFT calculation revealed that D4 was not directly responsible for the electrocatalytic activity of Pt; iv) electrochemical analysis demonstrated that the residual methyl groups of siloxane and various siloxanes did not hinder the proton transport in the polymer membrane; and v) siloxanes accumulated in the primary and secondary pores with the exception of an external surface of carbon, causing an increase in the oxygen reactant's resistance and resulting in a decrease of the cell performance. In addition, we confirmed that injection of D4 did not affect the carbon corrosion adversely because the siloxane had little influence on water sorption in the catalyst layer.

  1. A polymer electrolyte membrane fuel cell model with multi-species input

    Energy Technology Data Exchange (ETDEWEB)

    Rama, P.; Chen, R.; Thring, R.

    2005-06-15

    With the emerging realization that low temperature, low pressure polymer electrolyte membrane fuel cell (PEMFC) technologies can realistically serve for power-generation of any scale, the value of comprehensive simulation models becomes equally evident. Many models have been successfully developed over the last two decades. One of the fundamental limitations among these models is that up to only three constituent species have been considered in the dry pre-humidified anode and cathode inlet gases, namely oxygen and nitrogen for the cathode and hydrogen, carbon dioxide, and carbon monoxide for the anode. In order to extend the potential of theoretical study and to bring the simulation closer towards reality, in this research, a 1D steady-state, low temperature, isothermal, isobaric PEMFC model has been developed. The model accommodates multi-component diffusion in the porous electrodes and therefore offers the potential to further investigate the effects of contaminants such as carbon monoxide on cell performance. The simulated model polarizations agree well with published experimental data. It opens a wider scope to address the remaining limitations in the future with further developments. (author)

  2. Cathode and interdigitated air distributor geometry optimization in polymer electrolyte membrane (PEM) fuel cells

    International Nuclear Information System (INIS)

    A steady-state single-phase three-dimensional electro-chemical model is combined with a nonlinear constrained optimization procedure to maximize the performance of the cathode and the interdigitated air distributor in a polymer electrolyte membrane (PEM) fuel cell. The cathode and the interdigitated air distributor design parameters considered include: the cathode thickness, the thickness of the interdigitated air distributor channels and the width of the interdigitated air distributor channels. A statistical sensitivity analysis is used to determine robustness of the optimal PEM fuel cell design. The results of the optimization analysis show that higher current densities at the membrane/cathode interface are obtained in the PEM cathode and the interdigitated air distributor geometries that promote convective oxygen transport to the membrane/cathode interface and reduce the thickness of the boundary diffusion layer at the same interface. The statistical sensitivity analysis results show that, while the predicted average current density at the membrane/cathode interface is affected by uncertainties in a number of model parameters, the optimal designs of the PEM cathode and the interdigitated air distributor are quite robust

  3. Biodegradation test of SPS-LS blends as polymer electrolyte membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Putri, Zufira, E-mail: zufira.putri@gmail.com, E-mail: arcana@chem.itb.ac.id; Arcana, I Made, E-mail: zufira.putri@gmail.com, E-mail: arcana@chem.itb.ac.id [Inorganic and Physical Chemistry Research Groups, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Bandung (Indonesia)

    2014-03-24

    Sulfonated polystyrene (SPS) can be applied as a proton exchange membrane fuel cell due to its fairly good chemical stability. In order to be applied as polymer electrolyte membrane fuel cells (PEMFCs), membrane polymer should have a good ionic conductivity, high proton conductivity, and high mechanical strength. Lignosulfonate (LS) is a complex biopolymer which has crosslinks and sulfonate groups. SPS-LS blends with addition of SiO{sub 2} are used to increase the proton conductivity and to improve the mechanical properties and thermal stability. However, the biodegradation test of SPS-LS blends is required to determine whether the application of these membranes to be applied as an environmentally friendly membrane. In this study, had been done the synthesis of SPS, biodegradability test of SPS-LS blends with variations of LS and SiO{sub 2} compositions. The biodegradation test was carried out in solid medium of Luria Bertani (LB) with an activated sludge used as a source of microorganism at incubation temperature of 37°C. Based on the results obtained indicated that SPS-LS-SiO{sub 2} blends are more decomposed by microorganism than SPS-LS blends. This result is supported by analysis of weight reduction percentage, functional groups with Fourier Transform Infrared (FTIR) Spectroscopy, and morphological surface with Scanning Electron Microscopy (SEM)

  4. Biodegradation test of SPS-LS blends as polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Putri, Zufira; Arcana, I. Made

    2014-03-01

    Sulfonated polystyrene (SPS) can be applied as a proton exchange membrane fuel cell due to its fairly good chemical stability. In order to be applied as polymer electrolyte membrane fuel cells (PEMFCs), membrane polymer should have a good ionic conductivity, high proton conductivity, and high mechanical strength. Lignosulfonate (LS) is a complex biopolymer which has crosslinks and sulfonate groups. SPS-LS blends with addition of SiO2 are used to increase the proton conductivity and to improve the mechanical properties and thermal stability. However, the biodegradation test of SPS-LS blends is required to determine whether the application of these membranes to be applied as an environmentally friendly membrane. In this study, had been done the synthesis of SPS, biodegradability test of SPS-LS blends with variations of LS and SiO2 compositions. The biodegradation test was carried out in solid medium of Luria Bertani (LB) with an activated sludge used as a source of microorganism at incubation temperature of 37°C. Based on the results obtained indicated that SPS-LS-SiO2 blends are more decomposed by microorganism than SPS-LS blends. This result is supported by analysis of weight reduction percentage, functional groups with Fourier Transform Infrared (FTIR) Spectroscopy, and morphological surface with Scanning Electron Microscopy (SEM).

  5. Improvement of the thermal stability of LiMn2O4/graphite cells with methylene methanedisulfonate as electrolyte additive

    International Nuclear Information System (INIS)

    In order to overcome the severe capacity fading of LiMn2O4/graphite cells cycled at elevated temperature, methylene methanedisulfonate (MMDS) is newly evaluated as an electrolyte additive to improve the thermal stability of LiMn2O4 cathode. The cell using 1.0 mol L−1LiPF6 -EC/EMC/DMC (1:1:1, weight ratio) with 0.5 wt.% MMDS additive keeps 79.2% of initial capacity after100 cycles at 60 °C, whereas it is only 52.7% for the cell without additive. After the storage at 85 °C for 24 h, the cell with 0.5 wt.% MMDS additive exhibits higher discharge capacity retention (82.5%) than the cell without additive (71.8%), and the change of thickness, resistance and discharge voltage plateaus decrease. The effects of the additive are characterized by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), transmission electron microscopy (TEM), as well as electrochemical performance tests. These results suggest that MMDS additive can form better electrochemical and thermal stability of surface film on the LiMn2O4 electrode, which reduces both the decomposition of the electrolyte and the dissolution of Mn ion in the electrolyte at elevated temperature, thus leads to the obvious improvement on the thermal stability of LiMn2O4 cathode

  6. A polymer electrolyte fuel cell stack for stationary power generation from hydrogen fuel

    Energy Technology Data Exchange (ETDEWEB)

    Gottesfeld, S. [Los Alamos National Lab., NM (United States)

    1995-09-01

    The fuel cell is the most efficient device for the conversion of hydrogen fuel to electric power. As such, the fuel cell represents a key element in efforts to demonstrate and implement hydrogen fuel utilization for electric power generation. The low temperature, polymer electrolyte membrane fuel cell (PEMFC) has recently been identified as an attractive option for stationary power generation, based on the relatively simple and benign materials employed, the zero-emission character of the device, and the expected high power density, high reliability and low cost. However, a PEMFC stack fueled by hydrogen with the combined properties of low cost, high performance and high reliability has not yet been demonstrated. Demonstration of such a stack will remove a significant barrier to implementation of this advanced technology for electric power generation from hydrogen. Work done in the past at LANL on the development of components and materials, particularly on advanced membrane/electrode assemblies (MEAs), has contributed significantly to the capability to demonstrate in the foreseeable future a PEMFC stack with the combined characteristics described above. A joint effort between LANL and an industrial stack manufacturer will result in the demonstration of such a fuel cell stack for stationary power generation. The stack could operate on hydrogen fuel derived from either natural gas or from renewable sources. The technical plan includes collaboration with a stack manufacturer (CRADA). It stresses the special requirements from a PEMFC in stationary power generation, particularly maximization of the energy conversion efficiency, extension of useful life to the 10 hours time scale and tolerance to impurities from the reforming of natural gas.

  7. Mathematical Modeling of Transport Phenomena in Polymer Electrolyte and Direct Methanol Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Birgersson, Erik

    2004-02-01

    This thesis deals with modeling of two types of fuel cells: the polymer electrolyte fuel cell (PEFC) and the direct methanol fuel cell (DMFC), for which we address four major issues: a) mass transport limitations; b) water management (PEFC); c) gas management (DMFC); d) thermal management. Four models have been derived and studied for the PEFC, focusing on the cathode. The first exploits the slenderness of the cathode for a two-dimensional geometry, leading to a reduced model, where several non dimensional parameters capture the behavior of the cathode. The model was extended to three dimensions, where four different flow distributors were studied for the cathode. A quantitative comparison shows that the interdigitated channels can sustain the highest current densities. These two models, comprising isothermal gas phase flow, limit the studies to (a). Returning to a two-dimensional geometry of the PEFC, the liquid phase was introduced via a separate flow model approach for the cathode. In addition to conservation of mass, momentum and species, the model was extended to consider simultaneous charge and heat transfer for the whole cell. Different thermal, flow fields, and hydrodynamic conditions were studied, addressing (a), (b) and (d). A scale analysis allowed for predictions of the cell performance prior to any computations. Good agreement between experiments with a segmented cell and the model was obtained. A liquid-phase model, comprising conservation of mass, momentum and species, was derived and analyzed for the anode of the DMFC. The impact of hydrodynamic, electrochemical and geometrical features on the fuel cell performance were studied, mainly focusing on (a). The slenderness of the anode allows the use of a narrow-gap approximation, leading to a reduced model, with benefits such as reduced computational cost and understanding of the physical trends prior to any numerical computations. Adding the gas-phase via a multiphase mixture approach, the gas

  8. Ionic conductivity studies of solid oxide fuel cell electrolytes and theoretical modeling of an entire solid oxide fuel cell

    Science.gov (United States)

    Pornprasertsuk, Rojana

    Because of the steep increase in oil prices, the global warming effect and the drive for energy independence, alternative energy research has been encouraged worldwide. The sustainable fuels such as hydrogen, biofuel, natural gas, and solar energy have attracted the attention of researchers. To convert these fuels into a useful energy source, an energy conversion device is required. Fuel cells are one of the energy conversion devices which convert chemical potentials into electricity. Due to their high efficiency, the ease to scale from 1 W range to megawatts range, no recharging requirement and the lack of CO2 and NOx emission (if H2 and air/O 2 are used), fuel cells have become a potential candidate for both stationary power generators and portable applications. This thesis has been focused primarily on solid oxide fuel cell (SOFC) studies due to its high efficiency, varieties of fuel choices, and no water management problem. At the present, however, practical applications of SOFCs are limited by high operating temperatures that are needed to create the necessary oxide-ion vacancy mobility in the electrolyte and to create sufficient electrode reactivities. This thesis introduces several experimental and theoretical approaches to lower losses both in the electrolyte and the electrodes. Yttria stabilized zirconia (YSZ) is commonly used as a solid electrolyte for SOFCs due to its high oxygen-ion conductivity. To improve the ionic conductivity for low temperature applications, an approach that involves dilating the structure by irradiation and introducing edge dislocations into the electrolyte was studied. Secondly, to understand the activation loss in SOFC, the kinetic Monte Carlo (KMC) technique was implemented to model the SOFC operation to determining the rate-limiting step due to the electrodes on different sizes of Pt catalysts. The isotope exchange depth profiling technique was employed to investigate the irradiation effect on the ionic transport in different

  9. Composite electrolytes composed of Cs-substituted phosphotungstic acid and sulfonated poly(ether-ether ketone) for fuel cell systems

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Song-Yul, E-mail: ms089203@tutms.tut.ac.jp [Department of Materials Science, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan); Yoshida, Toshihiro; Kawamura, Go [Department of Materials Science, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan); Muto, Hiroyuki [Department of Materials Science and Engineering, Kurume National College of Technology, 1-1-1 Komorino, Kurume, Fukuoka 830-8555 (Japan); Sakai, Mototsugu [Department of Materials Science, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan); Matsuda, Atsunori, E-mail: matsuda@tutms.tut.ac.jp [Department of Materials Science, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan)

    2010-10-15

    Composite electrolytes composed of cesium hydrogen sulfate containing phosphotungstic acids (CsHSO{sub 4}-H{sub 3}PW{sub 12}O{sub 40}) and sulfonated poly(ether-ether ketone) (SPEEK) were prepared by casting the corresponding precursor for application in fuel cells. Partially Cs-substituted phosphotungstic acids (Cs{sub x}H{sub 3-x}PW{sub 12}O{sub 40}) were formed in the CsHSO{sub 4}-H{sub 3}PW{sub 12}O{sub 40} system by mechanochemical treatment. SPEEK was prepared from PEEK by sulfonation using concentrated sulfuric acid. Flexible composite electrolytes were obtained and their electrochemical properties were markedly improved with the addition of Cs{sub x}H{sub 3-x}PW{sub 12}O{sub 40}, into the SPEEK matrix. A maximum power density of 213 mW cm{sup -2} was obtained from the single cell test for 50H{sub 3}PW{sub 12}O{sub 40}-50CsHSO{sub 4} in SPEEK (1/5 by weight) composite electrolyte at 80 deg. C and at 80 RH%. Electrochemical properties and transmission electron microscopy (TEM) results suggest that three-dimensional cluster particles were formed and homogeneously distributed in the SPEEK matrix. The mechanochemically synthesized Cs{sub x}H{sub 3-x}PW{sub 12}O{sub 40} incorporated into the SPEEK matrix increased the number of protonate sites in the electrolyte. The composite electrolytes were successfully formed with Cs{sub x}H{sub 3-x}PW{sub 12}O{sub 40}, which consist of hydrogen bonding between surface of inorganic solid acids and not only -HSO{sub 4}{sup -} dissociated from CsHSO{sub 4} but also -SO{sub 3}H groups in the SPEEK.

  10. Efficiency enhancement of dye-sensitized solar cells with addition of additives (single/binary) to ionic liquid electrolyte

    Indian Academy of Sciences (India)

    H-S Lee; S-H Bae; C-H Han; S S Sekhon

    2012-11-01

    The effect of addition of single and binary additives on the performance of dye-sensitized TiO2 solar cells based on electrolytes containing an ionic liquid (IL), 1,2-dimethyl-3-propylimidazolium iodide (DMPII) has been studied. Among the seven additives used, the addition of 2-(dimethylamino)-pyridine (DMAP) to IL resulted in best cell efficiency, which showed further enhancement with the addition of 5-chloro-1-ethyl-2-methylimidazole (CEMI) as second additive. The efficiency of the dye-sensitized solar cell (DSC) based on an electrolyte containing binary additives (DMAP and CEMI in equal molar ratios) has been found to increase by 62.5% from 4.35 to 7.07%. The dependence of different photovoltaic performance parameters (\\oc, sc, , ) of DSC upon temperature has been studied over a 30–120°C range and only a small decrease in conversion efficiency has been observed. The electrolyte containing binary additives (DMAP and CEMI) shows best cell performance up to 120°C.

  11. Analysis on the effect of polysulfide electrolyte composition for higher performance of Si quantum dot-sensitized solar cells

    International Nuclear Information System (INIS)

    Quantum dot-sensitized solar cell (QDSC) based on multiple exciton generation of QD has been expected to realize high efficiency. This work focused on Si QD instead of conventional QD materials because of their toxicity and scarcity. Si QDs were fabricated by multi-hollow discharge plasma chemical vapor deposition. General QDSCs use polysulfide electrolyte because it is suitable for stabilizing QDs and its redox reaction is the best as compared with other redox systems. The improvement of redox reaction which is one of the slowest reactions in the kinetic analysis is closely connected with the enhancement of performance. For the enhancement on the overall performance of Si QDSC, the performance dependence on electrolyte composition was investigated. The concentrations of Na2S and S were varied for the activation of redox reaction and KCl concentration was optimized for the improvement of electrolyte characteristics. Consequently, the best performance of Si QDSC was obtained with 1 M Na2S, 2 M S, and 0.4 M KCl polysulfide electrolyte

  12. Fabrication of Stable Dye Sensitized Solar Cell with Gel electrolytes Using Poly(ethylene oxide)-Poly(ethylene glycol)

    International Nuclear Information System (INIS)

    Fabrication of quasi solid state dye sensitized solar cell with a stable gel electrolyte employing poly(ethylene oxide) (PEO)-poly(ethylene glycol) (PEG) is reported in this paper. PEO-PEG with either one of alkali iodides (LiI or NaI or KI), 1,2-dimethyl-3-propyl imidazolium iodide (DMPI), 4-tertbutylpyridine (TBP) and iodine in acetonitrile were used for the gel electrolyte preparation. The ionic conductivity and the triiodide diffusion coefficient of the gel electrolytes were measured by Electrochemical Impedance Spectroscopy. The photoconversion efficiency of gel state DSSC with NaI was found to be 5.4% at 100 mW/cm2 with AM 1.5 Gfilter. When nanocrystalline TiO2 was used as the filler in the gel electrolyte, the photoconversion efficiency was found to be increased up to 6.3%. The quasi solid state DSSC retained its initial value for 600 hours aging under ambient conditions

  13. Contact Resistance of Tantalum Coatings in Fuel Cells and Electrolyzers using Acidic Electrolytes at Elevated Temperatures

    DEFF Research Database (Denmark)

    Jensen, Annemette Hindhede; Christensen, Erik; Barner, Jens H. Von

    2014-01-01

    Tantalum has so far been found to be the only construction material with sufficient corrosion resistance for high temperature polymer electrolyte membrane electrolyzers using acidic electrolytes above 100◦C. In this work the interfacial contact resistances of tantalum plates and tantalum coated...... stainless steel were found to be far below the US Department of Energy target value of 10mcm2. The good contact resistance of tantalum was demonstrated by simulating high temperature polymer electrolyte membrane electrolysis conditions by anodization performed in 85% phosphoric acid at 130◦C, followed by...

  14. A Review of Water Management in Polymer Electrolyte Membrane Fuel Cells

    Directory of Open Access Journals (Sweden)

    Zidong Wei

    2009-11-01

    Full Text Available At present, despite the great advances in polymer electrolyte membrane fuel cell (PEMFC technology over the past two decades through intensive research and development activities, their large-scale commercialization is still hampered by their higher materials cost and lower reliability and durability. In this review, water management is given special consideration. Water management is of vital importance to achieve maximum performance and durability from PEMFCs. On the one hand, to maintain good proton conductivity, the relative humidity of inlet gases is typically held at a large value to ensure that the membrane remains fully hydrated. On the other hand, the pores of the catalyst layer (CL and the gas diffusion layer (GDL are frequently flooded by excessive liquid water, resulting in a higher mass transport resistance. Thus, a subtle equilibrium has to be maintained between membrane drying and liquid water flooding to prevent fuel cell degradation and guarantee a high performance level, which is the essential problem of water management. This paper presents a comprehensive review of the state-of-the-art studies of water management, including the experimental methods and modeling and simulation for the characterization of water management and the water management strategies. As one important aspect of water management, water flooding has been extensively studied during the last two decades. Herein, the causes, detection, effects on cell performance and mitigation strategies of water flooding are overviewed in detail. In the end of the paper the emphasis is given to: (i the delicate equilibrium of membrane drying vs. water flooding in water management; (ii determining which phenomenon is principally responsible for the deterioration of the PEMFC performance, the flooding of the porous electrode or the gas channels in the bipolar plate, and (iii what measures should be taken to prevent water flooding from happening in PEMFCs.

  15. The preparation of carbon dots/ionic liquids-based electrolytes and their applications in quasi-solid-state dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Highlights: ► A facile means to generate carbon dots/ionic liquids (ILs) – were demonstrated. ► The carbon dots/ILs blend were used for fabricating quasi-solid-state DSSCs. ► Cells exhibited good stability in room temperature without any further sealing. -- Abstract: A facile means to generate carbon dots/ionic liquids (ILs) blend using ionic liquid-assisted electrochemical exfoliation was demonstrated. Two kinds of ILs, 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) and 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]), were used in this work. Transmission electron microscopy and UV–vis spectrum were employed to characterize the formed carbon dots/ILs. The carbon dots/ILs were used for fabricating quasi-solid-state dye-sensitized solar cells (DSSCs), where 1-butyl-3-methylimidazolium iodide and LiI/I2 were added to enhance the performance of DSSCs. Effects of the varied contents of components in the complex on the performance of DCCSs have been studied in detail at ambient temperature. The electrochemical impedance spectroscopy showed that the introduction of carbon dots into ionic liquids can enhance the electrical properties by facilitating charge transfer processes of the electrolytes. The overall energy-conversion efficiency (η) was 2.71% and 2.41% for carbon dots/[bmim][PF6] and carbon dots/[bmim][BF4] based blend electrolytes, respectively. A 82% enhancement in η was obtained by introduction of carbon dots into [bmim][PF6] comparing with pure [bmim][PF6] (η = 1.49%). In addition, the cells exhibited good stability under continuous illumination in room temperature without any further sealing

  16. Approaches and Recent Development of Polymer Electrolyte Membranes For Fuel Cells Operational Above 100°C

    DEFF Research Database (Denmark)

    Li, Qingfeng; He, Ronghuan; Jensen, Jens Oluf;

    2003-01-01

    encompassing modified PFSA membranes, alternative sulfonated polymer and their composite membranes, and acidbase complex membranes. PFSA membranes have been modified by swelling with nonvolatile solvents and preparing composites with hydrophilic oxides and solid proton conductors. DMFC and H2/O2(air) cells......The state-of-the-art of polymer electrolyte membrane fuel cell (PEMFC) technology is based on perfluorosulfonic acid (PFSA) polymer membranes operating at a typical temperature of 80 °C. Some of the key issues and shortcomings of the PFSA-based PEMFC technology are briefly discussed. These include...... water management, CO poisoning, hydrogen, reformate and methanol as fuels, cooling, and heat recovery. As a means to solve these shortcomings, hightemperature polymer electrolyte membranes for operation above 100 °C are under active development. This treatise is devoted to a review of the area...

  17. Thermodynamic stability of Na2ZrO3 using the solid electrolyte galvanic cell technique

    International Nuclear Information System (INIS)

    The sodium potential in the test electrode (a) Pt,O2,Na2ZrO3,ZrO2 was measured by using the emf technique employing Na-β''-alumina as the solid electrolyte in conjunction with (b) Pt,O2,Al2O3,NaAl11O17, (c) Pt,O2,Na2MoO4,Na2Mo2O7 and (d) Pt,Na2CO3,CO2,O2 as the reference electrodes over the ranges 880-1045, 700-800 and 850-940 K, respectively. The emf results between electrodes (b) and (c) were utilized for internal consistency checks. From the results on cells formed between (a) and (b) and those on (a) and (c), the standard Gibbs energy of formation, ΔfGo (kJ/mol) of Na2ZrO3 was determined to be -1699.4+0.3652T (K) valid over the temperature range 700-1045 K. The break in the emf data at 1045 K was corroborated by independent TG/DTA measurements carried out on Na2ZrO3 which exhibited an endotherm at 1055 K indicative of a phase transition in Na2ZrO3

  18. Radiation-Grafted Polymer Electrolyte Membranes for Water Electrolysis Cells: Evaluation of Key Membrane Properties.

    Science.gov (United States)

    Albert, Albert; Barnett, Alejandro O; Thomassen, Magnus S; Schmidt, Thomas J; Gubler, Lorenz

    2015-10-14

    Radiation-grafted membranes can be considered an alternative to perfluorosulfonic acid (PFSA) membranes, such as Nafion, in a solid polymer electrolyte electrolyzer. Styrene, acrylonitrile, and 1,3-diisopropenylbenzene monomers are cografted into preirradiated 50 μm ethylene tetrafluoroethylene (ETFE) base film, followed by sulfonation to introduce proton exchange sites to the obtained grafted films. The incorporation of grafts throughout the thickness is demonstrated by scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX) analysis of the membrane cross-sections. The membranes are analyzed in terms of grafting kinetics, ion-exchange capacity (IEC), and water uptake. The key properties of radiation-grafted membranes and Nafion, such as gas crossover, area resistance, and mechanical properties, are evaluated and compared. The plot of hydrogen crossover versus area resistance of the membranes results in a property map that indicates the target areas for membrane development for electrolyzer applications. Tensile tests are performed to assess the mechanical properties of the membranes. Finally, these three properties are combined to establish a figure of merit, which indicates that radiation-grafted membranes obtained in the present study are promising candidates with properties superior to those of Nafion membranes. A water electrolysis cell test is performed as proof of principle, including a comparison to a commercial membrane electrode assembly (MEA). PMID:26393461

  19. Electrochemical performance and stability of thin film electrodes with metal oxides in polymer electrolyte fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Wesselmark, M., E-mail: maria.wesselmark@ket.kth.s [Applied Electrochemistry, School of Chemistry and Chemical Engineering, KTH, SE-100 44 Stockholm (Sweden); Wickman, B. [Competence Centre for Catalysis, Department of Applied Physics, Chalmers University of Technology, SE-412 96 Goeteborg (Sweden); Lagergren, C.; Lindbergh, G. [Applied Electrochemistry, School of Chemistry and Chemical Engineering, KTH, SE-100 44 Stockholm (Sweden)

    2010-11-01

    Thin film electrodes are prepared by thermal evaporation of nanometer thick layers of metal oxide and platinum on a gas diffusion layer (GDL), in order to evaluate different metal oxides' impact on the activity and stability of the platinum cathode catalyst in the polymer electrolyte fuel cell. Platinum deposited on tin, tantalum, titanium, tungsten and zirconium oxide is investigated and the morphology and chemistry of the catalysts are examined with scanning electron microscopy and X-ray photoelectron spectroscopy. Cyclic sweeps in oxygen and nitrogen are performed prior and after potential cycling degradation tests. Platinum seems to disperse better on the metal oxides than on the GDL and increased electrochemically active surface area (ECSA) of platinum is observed on tin, titanium and tungsten oxide. A thicker layer metal oxide results in a higher ECSA. Platinum deposited on tungsten performs better than sole platinum in the polarisation curves and displays higher Tafel slopes at higher current densities than all other samples. The stability does also seem to be improved by the addition of tungsten oxide, electrodes with 3 nm platinum on 3, 10 and 20 nm tungsten oxide, performs better than all other electrodes after the accelerated degradation tests.

  20. Heat and water transport in a polymer electrolyte fuel cell electrode

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, Partha P [Los Alamos National Laboratory; Mukundan, Rangachary [Los Alamos National Laboratory; Borup, Rod L [Los Alamos National Laboratory; Ranjan, Devesh [TEXAS A& M UNIV

    2010-01-01

    In the present scenario of a global initiative toward a sustainable energy future, the polymer electrolyte fuel cell (PEFC) has emerged as one of the most promising alternative energy conversion devices for various applications. Despite tremendous progress in recent years, a pivotal performance limitation in the PEFC comes from liquid water transport and the resulting flooding phenomena. Liquid water blocks the open pore space in the electrode and the fibrous diffusion layer leading to hindered oxygen transport. The electrode is also the only component in the entire PEFC sandwich which produces waste heat from the electrochemical reaction. The cathode electrode, being the host to several competing transport mechanisms, plays a crucial role in the overall PEFC performance limitation. In this work, an electrode model is presented in order to elucidate the coupled heat and water transport mechanisms. Two scenarios are specifically considered: (1) conventional, Nafion{reg_sign} impregnated, three-phase electrode with the hydrated polymeric membrane phase as the conveyer of protons where local electro-neutrality prevails; and (2) ultra-thin, two-phase, nano-structured electrode without the presence of ionomeric phase where charge accumulation due to electro-statics in the vicinity of the membrane-CL interface becomes important. The electrode model includes a physical description of heat and water balance along with electrochemical performance analysis in order to study the influence of electro-statics/electro-migration and phase change on the PEFC electrode performance.

  1. 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.

  2. Ligand Engineering for the Efficient Dye-Sensitized Solar Cells with Ruthenium Sensitizers and Cobalt Electrolytes.

    Science.gov (United States)

    Aghazada, Sadig; Gao, Peng; Yella, Aswani; Marotta, Gabriele; Moehl, Thomas; Teuscher, Joël; Moser, Jacques-E; De Angelis, Filippo; Grätzel, Michael; Nazeeruddin, Mohammad Khaja

    2016-07-01

    Over the past 20 years, ruthenium(II)-based dyes have played a pivotal role in turning dye-sensitized solar cells (DSCs) into a mature technology for the third generation of photovoltaics. However, the classic I3(-)/I(-) redox couple limits the performance and application of this technique. Simply replacing the iodine-based redox couple by new types like cobalt(3+/2+) complexes was not successful because of the poor compatibility between the ruthenium(II) sensitizer and the cobalt redox species. To address this problem and achieve higher power conversion efficiencies (PCEs), we introduce here six new cyclometalated ruthenium(II)-based dyes developed through ligand engineering. We tested DSCs employing these ruthenium(II) complexes and achieved PCEs of up to 9.4% using cobalt(3+/2+)-based electrolytes, which is the record efficiency to date featuring a ruthenium-based dye. In view of the complicated liquid DSC system, the disagreement found between different characterizations enlightens us about the importance of the sensitizer loading on TiO2, which is a subtle but equally important factor in the electronic properties of the sensitizers. PMID:27322854

  3. Effect of fuel utilization on the carbon monoxide poisoning dynamics of Polymer Electrolyte Membrane Fuel Cells

    Science.gov (United States)

    Pérez, Luis C.; Koski, Pauli; Ihonen, Jari; Sousa, José M.; Mendes, Adélio

    2014-07-01

    The effect of fuel utilization on the poisoning dynamics by carbon monoxide (CO) is studied for future automotive conditions of Polymer Electrolyte Membrane Fuel Cells (PEMFC). Three fuel utilizations are used, 70%, 40% and 25%. CO is fed in a constant concentration mode of 1 ppm and in a constant molar flow rate mode (CO concentrations between 0.18 and 0.57 ppm). The concentrations are estimated on a dry gas basis. The CO concentration of the anode exhaust gas is analyzed using gas chromatography. CO is detected in the anode exhaust gas almost immediately after it is added to the inlet gas. Moreover, the CO concentration of the anode exhaust gas increases with the fuel utilization for both CO feed modes. It is demonstrated that the lower the fuel utilization, the higher the molar flow rate of CO at the anode outlet at early stages of the CO poisoning. These results suggest that the effect of CO in PEMFC systems with anode gas recirculation is determined by the dynamics of its accumulation in the recirculation loop. Consequently, accurate quantification of impurities limits in current fuel specification (ISO 14687-2:2012) should be determined using anode gas recirculation.

  4. Cell-Assisted Lipotransfer: A Systematic Review of Its Efficacy

    OpenAIRE

    Toyserkani, Navid Mohamadpour; Quaade, Marlene Louise; Sørensen, Jens Ahm

    2016-01-01

    Introduction Autologous lipotransfer is seen as an ideal filler for soft tissue reconstruction. The main limitation of this procedure is the unpredictable resorption and volume loss of the fat graft. In the recent decade, an increasing amount of research has focused on the use of adipose tissue-derived stromal cells (ASCs) to enrich the fat graft, a procedure termed cell-assisted lipotransfer (CAL). The aim of this review was to systematically review the current preclinical and clinical evide...

  5. New Polymer Electrolyte Membranes Based on Acid Doped PBI For Fuel Cells Operating above 100°C

    DEFF Research Database (Denmark)

    Li, Qingfeng

    The technical achievement and challenges for the PEMFC technology based on perfluorosulfonic acid (PFSA) polymer membranes (e.g. Nafion®) are briefly discussed. The newest development for alternative polymer electrolytes for operation above 100°C. As one of the successful approaches to high...... operational temperatures, the development and evaluation of acid doped PBI membranes are reviewed, covering polymer synthesis, membrane casting, acid doping, physiochemical characterization and fuel cell tests....

  6. Effect of Deoxycholic Acid on the Performance of Liquid Electrolyte Dye-Sensitized Solar Cells Using a Perylene Monoimide Derivative

    OpenAIRE

    Mikroyannidis, John A.; Rajnish Kurchania; Ball, Richard J.; Sharma, Ganesh D.; Roy, Mahesh S.

    2012-01-01

    The effect of coadsorption with deoxycholic acid (DCA) on the performance of dye-sensitized solar cell based on perylene monoimide derivative (PCA) as sensitizer and liquid electrolyte had been investigated. The current-voltage characteristics under illumination and incident photon to current efficiency (IPCE) spectra of the DSSCs showed that the coadsorption of DCA with the PCA dye results in a significant improvement in short circuit photocurrent and slight increase in the open circuit phot...

  7. Synthesis of ozone from air via a polymer-electrolyte-membrane cell with a doped tin oxide anode

    OpenAIRE

    Wang, YH; Cheng, S.; Chan, KY

    2006-01-01

    The generation of ozone from air using an electrochemical cell consisting of an air cathode, a polymer-electrolyte-membrane (PEM), and a doped tin oxide anode is reported. This synthesis is environmentally friendly compared to the conventional high-voltage corona discharge process since NOx formation is eliminated; a higher ozone concentration is generated; and lower energy may be required. © The Royal Society of Chemistry 2006.

  8. Investigations of proton conducting polymers and gas diffusion electrodes in the polymer electrolyte fuel cell

    OpenAIRE

    Gode, Peter

    2005-01-01

    Polymer electrolyte fuel cells (PEFC) convert the chemically bound energy in a fuel, e.g. hydrogen, directly into electricity by an electrochemical process. Examples of future applications are energy conversion such as combined heat and power generation (CHP), zero emission vehicles (ZEV) and consumer electronics. One of the key components in the PEFC is the membrane / electrode assembly (MEA). Both the membrane and the electrodes consist of proton conducting polymers (ionomers). In the membr...

  9. Interface-designed Membranes with Shape-controlled Patterns for High-performance Polymer Electrolyte Membrane Fuel Cells

    OpenAIRE

    Yukwon Jeon; Dong Jun Kim; Jong Kwan Koh; Yunseong Ji; Jong Hak Kim; Yong-Gun Shul

    2015-01-01

    Polymer electrolyte membrane fuel cell is a promising zero-emission power generator for stationary/automotive applications. However, key issues, such as performance and costs, are still remained for an economical commercialization. Here, we fabricated a high-performance membrane electrode assembly (MEA) using an interfacial design based on well-arrayed micro-patterned membranes including circles, squares and hexagons with different sizes, which are produced by a facile elastomeric mold method...

  10. A Review on Current Status of Stability and Knowledge on Liquid Electrolyte-Based Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Frédéric Sauvage

    2014-01-01

    Full Text Available The purpose of this review is to gather the current background in materials development and provide the reader with an accurate image of today’s knowledge regarding the stability of dye-sensitized solar cells. This contribution highlights the literature from the 1970s to the present day on nanostructured TiO2, dye, Pt counter electrode, and liquid electrolyte for which this review is focused on.

  11. Estimation of electrode ionomer oxygen permeability and ionomer-phase oxygen transport resistance in polymer electrolyte fuel cells.

    Science.gov (United States)

    Sambandam, Satheesh; Parrondo, Javier; Ramani, Vijay

    2013-09-28

    The oxygen permeability of perfluorinated and hydrocarbon polymer electrolyte membranes (PEMs; Nafion®, SPEEK and SPSU), which are used as electrolytes and electrode ionomers in polymer electrolyte fuel cells (PEFCs), was estimated using chronoamperometry using a modified fuel cell set-up. A thin, cylindrical microelectrode was embedded into the PEM and used as the working electrode. The PEM was sandwiched between 2 gas diffusion electrodes, one of which was catalyzed and served as the counter and pseudo-reference electrode. Independently, from fuel cell experiments, the oxygen transport resistance arising due to transport through the ionomer film covering the catalyst active sites was estimated at the limiting current and decoupled from the overall mass transport resistance. The in situ oxygen permeability measured at 80 °C and 75% RH of perfluorinated ionomers such as Nafion® (3.85 × 10(12) mol cm(-1) s(-1)) was observed to be an order of magnitude higher than that of hydrocarbon-based PEMs such as SPEEK (0.27 × 10(12) mol cm(-1) s(-1)) and SPSU (0.15 × 10(12) mol cm(-1) s(-1)). The obtained oxygen transport (through ionomer film) resistance values (Nafion® - 1.6 s cm(-1), SPEEK - 2.2 s cm(-1) and SPSU - 3.0 s cm(-1); at 80 °C and 75% RH) correlated well with the measured oxygen permeabilities in these ion-containing polymers. PMID:23912796

  12. Efficiency of non-optimized direct carbon fuel cell with molten alkaline electrolyte fueled by carbonized biomass

    Science.gov (United States)

    Kacprzak, A.; Kobyłecki, R.; Włodarczyk, R.; Bis, Z.

    2016-07-01

    The direct carbon fuel cells (DCFCs) belong to new generation of energy conversion devices that are characterized by much higher efficiencies and lower emission of pollutants than conventional coal-fired power plants. In this paper the DCFC with molten hydroxide electrolyte is considered as the most promising type of the direct carbon fuel cells. Binary alkali hydroxide mixture (NaOH-LiOH, 90-10 mol%) is used as electrolyte and the biochar of apple tree origin carbonized at 873 K is applied as fuel. The performance of a lab-scale DCFC with molten alkaline electrolyte is investigated and theoretical, practical, voltage, and fuel utilization efficiencies of the cell are calculated and discussed. The practical efficiency is assessed on the basis of fuel HHV and LHV and the values are estimated at 40% and 41%, respectively. The average voltage efficiency is calculated as roughly 59% (at 0.65 V) and it is in a relatively good agreement with the values obtained by other researchers. The calculated efficiency of fuel utilization exceeds 95% thus indicating a high degree of carbon conversion into the electric power.

  13. Facile Multiscale Patterning by Creep-Assisted Sequential Imprinting and Fuel Cell Application.

    Science.gov (United States)

    Jang, Segeun; Kim, Minhyoung; Kang, Yun Sik; Choi, Yong Whan; Kim, Sang Moon; Sung, Yung-Eun; Choi, Mansoo

    2016-05-11

    The capability of fabricating multiscale structures with desired morphology and incorporating them into engineering applications is key to realizing technological breakthroughs by employing the benefits from both microscale and nanoscale morphology simultaneously. Here, we developed a facile patterning method to fabricate multiscale hierarchical structures by a novel approach called creep-assisted sequential imprinting. In this work, nanopatterning was first carried out by thermal imprint lithography above the glass transition temperature (Tg) of a polymer film, and then followed by creep-assisted imprinting with micropatterns based on the mechanical deformation of the polymer film under the relatively long-term exposure to mechanical stress at temperatures below the Tg of the polymer. The fabricated multiscale arrays exhibited excellent pattern uniformity over large areas. To demonstrate the usage of multiscale architectures, we incorporated the multiscale Nafion films into polymer electrolyte membrane fuel cell, and this device showed more than 10% higher performance than the conventional one. The enhancement was attributed to the decrease in mass transport resistance because of unique cone-shape morphology by creep-recovery effects and the increase in interfacial surface area between Nafion film and electrocatalyst layer. PMID:27116979

  14. Electrochemical cell studies on fluorinated natural graphite in propylene carbonate electrolyte with difluoromethyl acetate (MFA) additive for low temperature lithium battery application

    Indian Academy of Sciences (India)

    R Chandrasekaran; M Koh; Y Ozhawa; H Aaoyoma; T Nakajima

    2009-05-01

    Electrochemical cell performances of fluorinated natural graphite (abbreviated as FNG) electrode material was studied by using 1M of LiClO4- EC : DEC : PC (1 : 1 : 1 v%) electrolyte solution with and without 0.15% v/v fluorinated carboxylic ester additive difluoromethyl acetate-CHF2COOCH3 (MFA) at -10°C. The electrochemical cell performances were studied by cyclic voltammetry, galvanostatic charge-discharge and impedance analysis. The additive has proven its positive role with the electrolyte system and has shown the improved characterization over the blank electrolyte system.

  15. Water transport during startup and shutdown of polymer electrolyte fuel cell stacks

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X.; Tajiri, K.; Ahluwalia, R.K. [Argonne National Laboratory, 9700 S Cass Avenue, Argonne, IL 60439 (United States)

    2010-10-01

    A dynamic three-phase transport model is developed to analyze water uptake and transport in the membrane and catalyst layers of polymer electrolyte fuel cells during startup from subfreezing temperatures and subsequent shutdown. The initial membrane water content ({lambda}, the number of water molecules per sulfonic acid site) is found to be an important parameter that determines whether a successful unassisted self-start is possible. For a given initial subfreezing temperature at startup, there is a critical {lambda} ({lambda}{sub h}), above which self-start is not possible because the product water completely engulfs the catalyst layers with ice before the stack can warm-up to 0 C. There is a second value of {lambda} ({lambda}{sub l}), below which the stack can be self-started without forming ice. Between {lambda}{sub l} and {lambda}{sub h}, the stack can be self-started, but with intermediate formation of ice that melts as the stack warms up to 0 C. Both {lambda}{sub l} and {lambda}{sub h} are functions of the initial stack temperature, cell voltage at startup, membrane thickness, catalyst loading, and stack heat capacity. If the stack is purged during the previous shutdown by flowing air in the cathode passages, then depending on the initial amount of water in the membrane and gas diffusion layers and the initial stack temperature, it may not be possible to dry the membrane to the critical {lambda} for a subsequent successful startup. There is an optimum {lambda} for robust and rapid startup and shutdown. Startup and shutdown time and energy may be unacceptable if the {lambda} is much less than the optimum. Conversely, a robust startup from subfreezing temperatures cannot be assured if the {lambda} is much higher than this optimum. (author)

  16. Water transport during startup and shutdown of polymer electrolyte fuel cell stacks.

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X.; Tajiri, K.; Ahluwalia, R.; Nuclear Engineering Division

    2010-10-01

    A dynamic three-phase transport model is developed to analyze water uptake and transport in the membrane and catalyst layers of polymer electrolyte fuel cells during startup from subfreezing temperatures and subsequent shutdown. The initial membrane water content (?, the number of water molecules per sulfonic acid site) is found to be an important parameter that determines whether a successful unassisted self-start is possible. For a given initial subfreezing temperature at startup, there is a critical ? (?h), above which self-start is not possible because the product water completely engulfs the catalyst layers with ice before the stack can warm-up to 0 C. There is a second value of ? (?l), below which the stack can be self-started without forming ice. Between ?l and ?h, the stack can be self-started, but with intermediate formation of ice that melts as the stack warms up to 0 C. Both ?l and ?h are functions of the initial stack temperature, cell voltage at startup, membrane thickness, catalyst loading, and stack heat capacity. If the stack is purged during the previous shutdown by flowing air in the cathode passages, then depending on the initial amount of water in the membrane and gas diffusion layers and the initial stack temperature, it may not be possible to dry the membrane to the critical ? for a subsequent successful startup. There is an optimum ? for robust and rapid startup and shutdown. Startup and shutdown time and energy may be unacceptable if the ? is much less than the optimum. Conversely, a robust startup from subfreezing temperatures cannot be assured if the ? is much higher than this optimum.

  17. Numerical modeling and analysis of micro-porous layer effects in polymer electrolyte fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Kyungmun; Ju, Hyunchul [School of Mechanical Engineering, Inha University, 253 Yonghyun-Dong, Nam-Gu, Incheon 402-751 (Korea)

    2009-12-01

    It is well known that a micro-porous layer (MPL) plays a crucial role in the water management of polymer electrolyte fuel cells (PEFCs), and thereby, significantly stabilizes and improves cell performance. To ascertain the exact roles of MPLs, a numerical MPL model is developed in this study and incorporated with comprehensive, multi-dimensional, multi-phase fuel-cell models that have been devised earlier. The effects of different porous properties and liquid-entry pressures between an MPL and a gas diffusion layer (GDL) are examined via fully three-dimensional numerical simulations. First, when the differences in pore properties and wettability between the MPL and GDL are taken into account but the difference in the entry pressures is ignored, the numerical MPL model captures a discontinuity in liquid saturation at the GDL vertical stroke MPL interface. The simulation does not, however, capture the beneficial effects of an MPL on cell performance, predicting even lower performance than in the case of no MPL. On the other hand, when a high liquid-entry pressure in an MPL is additionally considered, the numerical MPL model predicts a liquid-free MPL and successfully demonstrates the phenomenon that the high liquid-entry pressure of the MPL prevents any liquid water from entering the MPL. Consequently, it is found from the simulation results that a liquid-free MPL significantly enhances the back-flow of water across the membrane into the anode, which, in turn, helps to avoid membrane dehydration and alleviate the level of GDL flooding. As a result, the model successfully reports the beneficial effects of MPLs on PEFC performance and predicts higher performance in the presence of MPLs (e.g., an increase of 67 mV at 1.5 A cm{sup -2}). This study provides a fundamental explanation of the function of MPLs and quantifies the influence of their porous properties and the liquid-entry pressure on water transport and cell performance. (author)

  18. Effects of oral powder electrolyte administration on packed cell volume, plasma chemistry parameters, and incidence of colic in horses participating in a 6-day 162-km trail ride

    OpenAIRE

    Walker, Wade T.; Callan, Robert J.; Hill, Ashley E.; Tisher, Kelly B.

    2014-01-01

    This study evaluated the effects of administering oral powder electrolytes on packed cell volume (PCV), plasma chemistry parameters, and incidence of colic in horses participating on a 6-day 162-km trail ride in which water was not offered ad libitum. Twenty-three horses received grain with powder electrolytes daily while 19 control horses received grain only. Horses were ridden approximately 32 km a day at a walk or trot. Packed cell volume and plasma chemistry parameters were analyzed daily...

  19. Exceptional durability enhancement of PA/PBI based polymer electrolyte membrane fuel cells for high temperature operation at 200°C

    DEFF Research Database (Denmark)

    Aili, David; Zhang, Jin; Jakobsen, Mark Tonny Dalsgaard; Zhu, Haijin; Yang, Tianyu; Liu, Jian; Forsyth, Maria; Pan, Chao; Jensen, Jens Oluf; Cleemann, Lars Nilausen; Jiang, San Ping; Li, Qingfeng

    2016-01-01

    The incorporation of phosphotungstic acid functionalized mesoporous silica in phosphoric acid doped polybenzimidazole (PA/PBI) substantially enhances the durability of PA/PBI based polymer electrolyte membrane fuel cells for high temperature operation at 200°C.......The incorporation of phosphotungstic acid functionalized mesoporous silica in phosphoric acid doped polybenzimidazole (PA/PBI) substantially enhances the durability of PA/PBI based polymer electrolyte membrane fuel cells for high temperature operation at 200°C....

  20. Optimization of a quasi-solid-state dye-sensitized solar cell employing a nanocrystal-polymer composite electrolyte modified with water and ethanol

    International Nuclear Information System (INIS)

    A quasi-solid-state dye-sensitized solar cell employing a poly(ethylene oxide)-poly(vinylidene fluoride) (PEO-PVDF)/TiO2 gel electrolyte modified by various concentrations of water and ethanol is described. It is shown that the introduction of water and ethanol prevents the crystallization of the polymer matrix, and enhances the free I-/I3- concentration and the networks for ion transportation in the electrolyte, thus leading to an improvement in conductivity. A high energy conversion efficiency of about 5.8% is achieved by controlling the additive concentration in the electrolyte. Optimization of the additive-modified electrolyte performance has been obtained by studying the cross-linking behavior of water and ethanol with Fourier transform infrared (FTIR), differential scanning calorimetry (DSC) and viscosity measurements, and the electrical conduction behavior of the electrolyte with impedance spectra measurements.

  1. Optimization of a quasi-solid-state dye-sensitized solar cell employing a nanocrystal-polymer composite electrolyte modified with water and ethanol.

    Science.gov (United States)

    Yang, Ying; Zhou, Cong-Hua; Xu, Sheng; Zhang, Jing; Wu, Su-Juan; Hu, Hao; Chen, Bo-Lei; Tai, Qi-Dong; Sun, Zheng-Hua; Liu, Wei; Zhao, Xing-Zhong

    2009-03-11

    A quasi-solid-state dye-sensitized solar cell employing a poly(ethylene oxide)-poly(vinylidene fluoride) (PEO-PVDF)/TiO2 gel electrolyte modified by various concentrations of water and ethanol is described. It is shown that the introduction of water and ethanol prevents the crystallization of the polymer matrix, and enhances the free I(-)/I(3)(-) concentration and the networks for ion transportation in the electrolyte, thus leading to an improvement in conductivity. A high energy conversion efficiency of about 5.8% is achieved by controlling the additive concentration in the electrolyte. Optimization of the additive-modified electrolyte performance has been obtained by studying the cross-linking behavior of water and ethanol with Fourier transform infrared (FTIR), differential scanning calorimetry (DSC) and viscosity measurements, and the electrical conduction behavior of the electrolyte with impedance spectra measurements. PMID:19417514

  2. Conducting polymer-based counter electrode for a quantum-dot-sensitized solar cell (QDSSC) with a polysulfide electrolyte

    International Nuclear Information System (INIS)

    Highlights: ► This is the first report on the use of conducting polymers as counter electrode catalysts for quantum-dot-sensitized solar cells (QDSSCs). ► Conducting polymer materials, i.e., polythiophene (PT), polypyrrole (PPy), and poly(3,4-ethylenedioxythiophene) (PEDOT) were used to prepare counter electrodes for QDSSCs. ► The influences of morphology of the PEDOT-based counter electrode (CE) on the performance of its QDSSC were studied. ► PEDOT electrode exhibits well electrocatalytic activity and stability in the polysulfide electrolyte. ► The efficiency for the QDSSC with PEDOT-CE (1.35%) is comparable to that of the cell with sputtered-Au CE (1.33%). - Abstract: Conducting polymer materials, i.e., polythiophene (PT), polypyrrole (PPy), and poly(3,4-ethylenedioxythiophene) (PEDOT) were used to prepare counter electrodes (CEs) for quantum-dot-sensitized solar cells (QDSSCs). The QDSSC with PEDOT-CE exhibited the highest solar-to-electricity conversion efficiency (η) of 1.35%, which is remarkably higher than those of the cells with PT-CE (0.09%) and PPy-CE (0.41%) and very slightly higher than that of the cell with sputtered-gold-CE (1.33%). Electrochemical impedance spectra (EIS) show that this highest conversion efficiency of the PEDOT-based cell is due to higher electrocatalytic activity and reduced charge transfer resistance at the interface of the CE and the electrolyte, compared to those in the case of the cells with other conducting polymers and bare Au. Furthermore, the influences of morphology of the PEDOT film and the charge passed for its electropolymerization on the performance of its QDSSC were also studied. The higher porosity and surface roughness of the PEDOT matrix, with reference to those of other polymers are understood to be the reason for PEDOT to possess higher electrocatalytic activity at its interface with electrolyte.

  3. Comparison between numerical simulation and visualization experiment on water behavior in single straight flow channel polymer electrolyte fuel cells

    Science.gov (United States)

    Masuda, Hiromitsu; Ito, Kohei; Oshima, Toshihiro; Sasaki, Kazunari

    A relationship between a flooding and a cell voltage drop for polymer electrolyte fuel cell was investigated experimentally and numerically. A visualization cell, which has single straight gas flow channel (GFC) and observation window, was fabricated to visualize the flooding in GFC. We ran the cell with changing operation condition, and measured the time evolution of cell voltage and took the images of cathode GFC. Considering the operation condition, we executed a developed numerical simulation, which is based on multiphase mixture model with a formulation on water transport through the surface of polymer electrolyte membrane and the interface of gas diffusion layer/GFC. As a result in experiment, we found that the cell voltage decreased with time and this decrease was accelerated by larger current and smaller air flow rate. Our simulation succeeded to demonstrate this trend of cell voltage. In experiment, we also found that the water flushing in GFC caused an immediate voltage change, resulting in voltage recovery or electricity generation stop. Although our simulation could not replicate this immediate voltage change, the supersaturated area obtained by our simulation well corresponded to fogging area appeared on the window surface in the GFC.

  4. Enhanced Performance of Li|LiFePO4 Cells Using CsPF6 as an Electrolyte Additive

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Liang; Chen, Xilin; Cao, Ruiguo; Qian, Jiangfeng; Xiang, Hongfa; Zheng, Jianming; Zhang, Jiguang; Xu, Wu

    2015-10-20

    The practical application of lithium (Li) metal anode in rechargeable Li batteries is hindered by both the growth of Li dendrites and the low Coulombic efficiency (CE) during repeated charge/discharge cycles. Recently, we have discovered that CsPF6 as an electrolyte additive can significantly suppress Li dendrite growth and lead to highly compacted and well aligned Li nanorod structure during Li deposition on copper substrates. In this paper, the effect of CsPF6 additive on the performance of rechargeable Li metal batteries with lithium iron phosphate (LFP) cathode was further studied. Li|LFP coin cells with CsPF6 additive in electrolytes show well protected Li anode surface, decreased resistance, enhanced rate capability and extended cycling stability. In Li|LFP cells, the electrolyte with CsPF6 additive shows excellent long-term cycling stability (at least 500 cycles) at a charge current density of 0.5 mA cm-2 without internal short circuit. At high charge current densities, the effect of CsPF6 additive becomes less significant. Future work needs to be done to protect Li metal anode, especially at high charge current densities and for long cycle life.

  5. Enhanced performance of Li|LiFePO4 cells using CsPF6 as an electrolyte additive

    Science.gov (United States)

    Xiao, Liang; Chen, Xilin; Cao, Ruiguo; Qian, Jiangfeng; Xiang, Hongfa; Zheng, Jianming; Zhang, Ji-Guang; Xu, Wu

    2015-10-01

    The practical application of lithium (Li) metal anode in rechargeable Li batteries is hindered by both the growth of Li dendrites and the low Coulombic efficiency (CE) during repeated charge/discharge cycles. Recently, we have discovered that CsPF6 as an electrolyte additive can significantly suppress Li dendrite growth and lead to highly compacted and well aligned Li nanorod structures during Li deposition on copper substrates. In this paper, the effect of CsPF6 additive on the performance of rechargeable Li metal batteries with lithium iron phosphate (LFP) cathode is further studied. Li|LFP coin cells with CsPF6 additive in electrolytes show well protected Li anode surface, decreased resistance, enhanced rate capability and extended cycling stability. In Li|LFP cells, the electrolyte with CsPF6 additive shows excellent long-term cycling stability (at least 500 cycles) at a charge current density of 0.5 mA cm-2 without internal short circuit. At high charge current densities, the effect of CsPF6 additive becomes less significant. Future work needs to be done to protect Li metal anode, especially at high charge current densities and for long cycle life.

  6. Mass and charge transfer on various relevant scales in polymer electrolyte fuel cells[Dissertation 16991

    Energy Technology Data Exchange (ETDEWEB)

    Freunberger, S. A.

    2007-07-01

    This dissertation is concerned with the development, experimental diagnostics and mathematical modelling and simulation of polymer electrolyte fuel cells (PEFC). The central themes throughout this thesis are the closely interlinked phenomena of mass and charge transfer. In the face of developing a PEFC system for vehicle propulsion these phenomena are scrutinized on a broad range of relevant scales. Starting from the material related level of the membrane and the gas diffusion layer (GDL) we turn to length scales, where structural features of the cell additionally come into play. These are the scale of flow channels and ribs, the single cell and the cell stack followed by the cell, stack, and system development for an automotive power train. In Chapter 3 selected fundamental material models and properties, respectively, are explored that are crucial for the mathematical modelling and simulation of PEFC, as needed in some succeeding parts of this work. First, established mathematical models for mass and charge transfer in the membrane are compared within the framework of the membrane electrode assembly (MEA), which represents the electrochemical unit. Second, reliable values for effective diffusivities in the GDLs which are vital for the simulation of gaseous mass transport are measured. Therefore, a method is developed that allows measuring this quantity both as a function of compression and direction as this is a prerequisite of sophisticated more-dimensional numerical PEFC-models. Besides the cross section of the catalyst layer (CL) mass transfer under channels and ribs is considered as a major source of losses in particular under high load operation. As up to now there have been solely non-validated theoretical investigations, in Chapter 4 an experimental method is developed that is for the first time capable of resolving the current density distribution on the this scale. For this, the electron conductors in the cell are considered as 2-dimensional shunt

  7. Effects of surface chemistry and microstructure of electrolyte on oxygen reduction kinetics of solid oxide fuel cells

    Science.gov (United States)

    Park, Joong Sun; An, Jihwan; Lee, Min Hwan; Prinz, Fritz B.; Lee, Wonyoung

    2015-11-01

    We report systematic investigation of the surface properties of yttria-stabilized zirconia (YSZ) electrolytes with the control of the grain boundary (GB) density at the surface, and its effects on electrochemical activities. The GB density of thin surface layers deposited on single crystal YSZ substrates is controlled by changing the annealing temperature (750-1450 °C). Higher oxygen reduction reactions (ORR) kinetics is observed in samples annealed at lower temperatures. The higher ORR activity is ascribed to the higher GB density at the YSZ surface where 'mobile' oxide ion vacancies are more populated. Meanwhile, oxide ion vacancies concurrently created with yttrium segregation at the surface at the higher annealing temperature are considered inactive to oxygen incorporation reactions. Our results provide additional insight into the interplay between the surface chemistry, microstructures, and electrochemical activity. They potentially provide important guidelines for engineering the electrolyte-electrode interfaces of solid oxide fuel cells for higher electrochemical performance.

  8. U.S. DOE Progress Towards Developing Low-Cost, High Performance, Durable Polymer Electrolyte Membranes for Fuel Cell Applications

    Directory of Open Access Journals (Sweden)

    Dimitrios C. Papageorgopoulos

    2012-12-01

    Full Text Available Low cost, durable, and selective membranes with high ionic conductivity are a priority need for wide-spread adoption of polymer electrolyte membrane fuel cells (PEMFCs and direct methanol fuel cells (DMFCs. Electrolyte membranes are a major cost component of PEMFC stacks at low production volumes. PEMFC membranes also impose limitations on fuel cell system operating conditions that add system complexity and cost. Reactant gas and fuel permeation through the membrane leads to decreased fuel cell performance, loss of efficiency, and reduced durability in both PEMFCs and DMFCs. To address these challenges, the U.S. Department of Energy (DOE Fuel Cell Technologies Program, in the Office of Energy Efficiency and Renewable Energy, supports research and development aimed at improving ion exchange membranes for fuel cells. For PEMFCs, efforts are primarily focused on developing materials for higher temperature operation (up to 120 °C in automotive applications. For DMFCs, efforts are focused on developing membranes with reduced methanol permeability. In this paper, the recently revised DOE membrane targets, strategies, and highlights of DOE-funded projects to develop new, inexpensive membranes that have good performance in hot and dry conditions (PEMFC and that reduce methanol crossover (DMFC will be discussed.

  9. U.S. DOE Progress Towards Developing Low-Cost, High Performance, Durable Polymer Electrolyte Membranes for Fuel Cell Applications.

    Science.gov (United States)

    Houchins, Cassidy; Kleen, Greg J; Spendelow, Jacob S; Kopasz, John; Peterson, David; Garland, Nancy L; Ho, Donna Lee; Marcinkoski, Jason; Martin, Kathi Epping; Tyler, Reginald; Papageorgopoulos, Dimitrios C

    2012-01-01

    Low cost, durable, and selective membranes with high ionic conductivity are a priority need for wide-spread adoption of polymer electrolyte membrane fuel cells (PEMFCs) and direct methanol fuel cells (DMFCs). Electrolyte membranes are a major cost component of PEMFC stacks at low production volumes. PEMFC membranes also impose limitations on fuel cell system operating conditions that add system complexity and cost. Reactant gas and fuel permeation through the membrane leads to decreased fuel cell performance, loss of efficiency, and reduced durability in both PEMFCs and DMFCs. To address these challenges, the U.S. Department of Energy (DOE) Fuel Cell Technologies Program, in the Office of Energy Efficiency and Renewable Energy, supports research and development aimed at improving ion exchange membranes for fuel cells. For PEMFCs, efforts are primarily focused on developing materials for higher temperature operation (up to 120 °C) in automotive applications. For DMFCs, efforts are focused on developing membranes with reduced methanol permeability. In this paper, the recently revised DOE membrane targets, strategies, and highlights of DOE-funded projects to develop new, inexpensive membranes that have good performance in hot and dry conditions (PEMFC) and that reduce methanol crossover (DMFC) will be discussed. PMID:24958432

  10. Synthesis of carbon-supported titanium oxynitride nanoparticles as cathode catalyst for polymer electrolyte fuel cells

    International Nuclear Information System (INIS)

    Highlights: • A sol–gel route for the synthesis of rutile TiO2 was modified to synthesize TiOxNy-C. • N atoms were doped into TiOx nanoparticles solely by the heat-treatment under N2 gas. • The N2-treatment produced sites more active toward ORR compared with NH3-treatment. • TiOx doped with a small amount of N atoms are suggested to be responsible for ORR. -- Abstract: For use as the oxygen reduction reaction (ORR) catalyst in polymer electrolyte fuel cell cathodes, carbon-supported titanium oxynitride (TiOxNy-C) nanoparticles with a size of approximately 5 nm or less were synthesized without using NH3 gas. A sol–gel route developed for the synthesis of pure rutile TiO2 nanopowders was modified to prepare the carbon-supported titanium oxide nanoparticles (TiOx-C). For the first time, N atoms were doped into TiOx solely by heating TiOx-C under an inexpensive N2 atmosphere at 873 K for 3 h, which could be due to carbothermal reduction. The TiOx-C powder was also heated under NH3 gas at various temperatures (873–1273 K) and durations (3–30 h). This step resulted in the formation of a TiN phase irrespective of the heating conditions. Both N2- and NH3-treated TiOxNy-C did not crystallize well; however, the former showed a mass activity more than three times larger than that of the latter at 0.74 V versus the standard hydrogen electrode. Thus, titanium oxide nanoparticles doped with a small amount of N atoms are suggested to be responsible for catalyzing ORR in the case of N2-treated TiOxNy-C

  11. Preliminary Study of Membrane Preparation for Fuel Cell Polymer Electrolyte Membrane

    International Nuclear Information System (INIS)

    Proton conducting membranes for polymer electrolyte membrane fuel cells (PEMFC) have been prepared by radiation graft copolymerization of acrylic acid onto back bone polymers such as linear low density polyethylene (LLDPE), high density polyethylene (HDPE), and polypropylene (PP). Graft copolymers are prepared by γ-radiation and electron beam irradiation. The methods used are grafting on radiation-peroxide and grafting initiated by trapped radicals, in which the grafting reaction is done after the irradiation process (pre-irradiation grafting). The influence of the preparation conditions and the role of the initial polymer matrixes are studied. The degrees of grafting are determined by the total absorbed dose during irradiation, monomer’s concentration, grafting temperature, and the time of grafting. It is found that dose rate does not have a significant effect on the yield of grafting. The best suitable conditions for the grafting are as follows: 45 kGy for total dose, 40% (v/v) for monomer’s concentration, 70 °C for temperature and 90 minutes for period of grafting. Membranes based on different polymer matrixes show differences in their water uptake from liquid water. Apparently the ability of the membranes to take in the solvent depends on matrixes of the back bone polymers. It reflects the hydrophilic membranes properties. The preliminary characterization of the prepared grafted membranes is done by the treatment of metal uptake, using atomic absorption technique. The maximum uptake of the membranes for a given metal is Fe > Cu > Co except for LLDPE-g-Aac in which the uptake of Co > Cu. The maximum uptake of the membranes for a mixture of the metals in the same feed solution is Fe > Cu > Co. (author)

  12. Polymer electrolyte membranes for fuel cells by radiation induced grafting with electron beam irradiation: state-of-the-art

    International Nuclear Information System (INIS)

    Polymer electrolyte membranes have generated considerable interest in various fields of industrial interest due to their wide spread applications in fuel cells, batteries, electrolyzers sensors and actuators. Such diversity in applications implies a strong demand to architect the membranes towards particular properties for specific applications. Radiation induced grafting of vinyl and acrylic monomers into polymeric films, is an appealing method for producing various polymer electrolyte membranes. This method has the advantages of simplicity, controllability over the composition leading to tailored membrane properties and absence of shaping problem as preparation starts with substrate in a film form. It also has the flexibility of using various types of radiation sources such as gamma-rays and electron beam. Of all, electron beam (EB) accelerator is an advantageous source of high energy radiation that can initiate grafting reactions required for preparation of the membranes particularly when pilot scale production and commercial applications are sought. The grafting penetration can be varied from surface to bulk of membranes depending on the acceleration energy. This lecture reviews the-state of- the-art in the use of EB irradiation in preparation of composite and grafted polymer electrolyte membranes for fuel cell applications by radiation induced grafting with simultaneous irradiation and preirradiation methods. The use of simultaneous EB irradiation method was found to simplify the process and reduce the reaction time as well as the monomer consumption whereas the use of preirradiation method in a single-step route provides a shorter route to prepare polymer electrolyte membranes with improved properties and reduced cost in addition of setting basis for designing a continuous line to produce these membranes with dedicated EB facilities

  13. Industrial-grade rare-earth and perovskite oxide for high-performance electrolyte layer-free fuel cell

    OpenAIRE

    Xia, Chen; Wang, Baoyuan; Ma, Ying; Cai, Yixiao; Afzal, Muhammad; Liu, Yanyan; He, Yunjuan; ZHANG Wei; Dong, Wenjing; Li, Junjiao; Zhu, Bin

    2016-01-01

    In the present work, we report a composite of industrial-grade material LaCePr-oxide (LCP) and perovskite La0.6Sr0.4Co0.2Fe0.8O3-delta (LSCF) for advanced electrolyte layer-free fuel cells (EFFCs). The microstructure, morphology, and electrical properties of the LCP, LSCF, and LCP-LSCF composite were investigated and characterized by XRD, SEM, EDS, TEM, and EIS. Various ratios of LCP to LSCF in the composite were modulated to achieve balanced ionic and electronic conductivities. Fuel cell wit...

  14. Effect of titanium powder loading in gas diffusion layer of a polymer electrolyte unitized reversible fuel cell

    OpenAIRE

    Hwang, Chul Min; Ishida, Masayoshi; Ito,Hiroshi; Maeda, Tetsuhiko; Nakano, Akihiro; Kato, Atsushi; Yoshida, Tetsuya

    2012-01-01

    Polymer electrolyte-based unitized reversible fuel cells (URFCs) can be operated either as an electrolyzer to split water into hydrogen and oxygen using electric power or as a fuel cell to supply electric power when fed hydrogen and oxygen or air. In a URFC, titanium (Ti)-felt is used as a gas diffusion layer (GDL) in the oxygen electrode and typical carbon paper is used as a GDL in the hydrogen electrode. Here, first, Ti-powder was loaded into the Ti-felt GDL in URFCs to produce an effective...

  15. In search of nuclear fusion in electrolytic cells and in metal/gas systems

    Science.gov (United States)

    McCracken, D. R.; Paquette, J.; Boniface, H. A.; Graham, W. R. C.; Johnson, R. E.; Briden, N. A.; Cross, W. G.; Arneja, A.; Tennant, D. C.; Lone, M. A.; Buyers, W. J. L.; Chambers, K. W.; McIlwain, A. K.; Attas, E. M.; Dutton, R.

    1990-06-01

    It has been reported recently in the literature that unexpected thermal and nuclear effects (production of excess heat, neutrons, γ-rays, and tritium) can occur during the electrolysis of heavy water at palladium or titanium electrodes, or during temperature and pressure cycling of the titanium/deuterium gas system. We have attempted to reproduce some of these experiments. A variety of electrochemical cells having palladium cathodes in the form of wires, tubes, sheets, and rods have been used to electrolyze heavy water containing 0.1 mol.dm-3 LiOH, 0.1 mol.dn-3 LiOD or 0.5 mol.dm-3 D3PO4. Current densities of up to 200 mA.cm-2 were applied. The mass of the palladium cathodes covered the range from 1-40 grams and the surface area varied from 8-140 cm2. Neutron detection systems with low constant backgrounds were used to search for neutron emission during electrolysis. These included3He- and10BF3-based detectors. After running some of the cells for more than 30 days, no neutron emission above background could be detected. This puts upper limits of 0.5 s-1 and 2×10-23 fus. D-D.s-1 on the neutron emission and the fusion rate, respectively. A sensitive and accurate heat-flow calorimeter was built and used to monitor the energy balance of some of the cells during electrolysis. No unexpected heat effects were observed. This puts an upper limit of 0.13 W.cm-3 on the specific excess power. No enrichment of the electrolyte in tritium was evident after electrolysis. Experiments were also performed with the titanium/ deuterium gas system. These consisted of exposing titanium metal to a deuterium gas pressure of 40 atmospheres, lowering the temperature to -196°C, releasing the pressure and gradually warming the titanium to room temperature. No neutron emission above background was observed during these experiments, which puts upper limits of 0.5 s-1 and 4×10-25 fus.D-D.s-1 on the neutron emission and fusion rate, respectively.

  16. Field assisted sintering of fine-grained Li7-3xLa3Zr2AlxO12 solid electrolyte and the influence of the microstructure on the electrochemical performance

    Science.gov (United States)

    Botros, Miriam; Djenadic, Ruzica; Clemens, Oliver; Möller, Matthias; Hahn, Horst

    2016-03-01

    The synthesis and processing of fine-grained Li7-3xLa3Zr2AlxO12 (x = 0.15, 0.17, 0.20) solid electrolyte (LLZO) is performed for the first time using a combination of nebulized spray pyrolysis (NSP) and field assisted sintering technique (FAST). Using FAST, the grain growth is suppressed and highly dense ceramics with 93% of the theoretical density are obtained. A tetragonal lattice distortion is observed after the sintering process. Although this structural modification has been reported to have lower Li-ion mobility compared to the cubic modification, the total conductivity of the sample at room temperature is found to be 0.33 mS cm-1, i.e. comparable to phase-pure cubic LLZO. The activation energy of 0.38 eV is also comparable to the literature values. Galvanostatic cycling of a symmetrical cell Li|LLZO|Li shows a good cycling stability over 100 h. The interfacial resistance in contact with Li-metal is determined using alternating current impedance spectroscopy to be 76 Ω cm2 and 69 Ω cm2 before and after cycling at different current densities, respectively.

  17. Polypyrrole/poly(vinyl alcohol-co-ethylene) quasi-solid gel electrolyte for iodine-free dye-sensitized solar cells

    Science.gov (United States)

    Jung, Mi-Hee

    2014-12-01

    Conducting polymer gel electrolyte is synthesized using the Cl- doped polypyrrole (PPy)/1-buty-2,3-dimethylimidazolium iodide (BDI)/poly(vinyl alcohol-co-ethylene)(PVA-EL), which yield an overall energy-conversion efficiency of about 4.72% comparable to the liquid electrolyte 4.69% under irradiation at 100 mW cm-2 AM 1.5. The introduction of PPy and PVA-EL into the BDI (which dissolves in the dimethylsulfoxide) increases the ion conductivity and effectively decreases the charge transfer resistance in the PPy gel electrolyte/TiO2/dye interfaces. With the change of the PVA-EL composition, PPy gel electrolyte exhibits independence of the content of PVA-EL, which means ion conductivity of PPy gel electrolyte as a dominant role for the contribution of cell performance. Employing intensity-modulated photo-voltage spectroscopy, intensity-modulated photo-current spectroscopy, and charge-extraction measurement, it demonstrate that the effective charge collection in PPy gel electrolyte devices rather than liquid electrolyte one is occurred due to the larger diffusion coefficient and long electron lifetime, resulting in the higher-efficiency solar cell.

  18. Optimizing the mercury mass measurement in industrial electrolytic cells by the radio-tracer method at ININ

    International Nuclear Information System (INIS)

    One method used in the production of chlorine and sodium is the use of electrolytic cells for the separation of chlorine and sodium from the brine; the industries apply very intense electromagnetic fields in this process. The electrolytic cells use mercury as electrode. In a chlorine production plant inventories are determined by total amount of mercury in the plant annually, since mercury losses are large and a very important parameter is to control the mass of mercury for it is necessary to measure with great precision the losses made. There are several methods to determine the mass of mercury ranging from take samples and weigh, but this involves continuous interruption of the process creating downtimes which in turn represent economic losses giving a result delimiting productivity for the industrial sector. An alternative and attractive method is to use a radioactive tracer whose principle has a similar behavior to study objective. The inert mercury has to be neutron activated in a nuclear reactor to having the characteristics of a tracer; the result makes one of the isotopes of mercury. The tracer is transported taking into account the recommendations of the Comision Nacional de Seguridad Nuclear y Salvaguardias (Mexico), then it is injected into the electrolytic cells mixing with the mercury in the system. By a relative radioactivity measurement and one sample by gamma spectrometry per interest cell, the mass of mercury without stopping the process is obtained. For optimal use of radio-tracer method must be taken into account as important features: irradiation time of mercury, counting conditions, vial geometry, sample volume, sample cells, mixing time and half-life of the tracer. (Author)

  19. Enhanced high temperature cycling performance of LiMn2O4/graphite cells with methylene methanedisulfonate (MMDS) as electrolyte additive and its acting mechanism

    Institute of Scientific and Technical Information of China (English)

    Fengju Bian; Zhongru Zhang; Yong Yang

    2014-01-01

    The effects of methylene methanedisulfonate (MMDS) on the high-temperature (∼50◦C) cycle performance of LiMn2O4/graphite cells are investigated. By addition of 2 wt%MMDS into a routine electrolyte, the high-temperature cycling performance of LiMn2O4/graphite cells can be significantly improved. The analysis of differential capacity curves and energy-dispersive X-ray spectrometry (EDX) indicates that MMDS decomposed on both cathode and anode. The three-electrode system of pouch cell is used to reveal the capacity loss mechanism in the cells. It is shown that the capacity fading of cells without MMDS in the electrolytes is due to irreversible lithium consumption during cycling and irreversible damage of LiMn2O4 material, while the capacity fading of cell with 2 wt%MMDS in electrolytes mainly originated from irreversible lithium consumption during cycling.

  20. Effect of Poly(Ether Urethane) Introduction on the Performance of Polymer Electrolyte for All-Solid-State Dye-Sensitized Solar Cells

    International Nuclear Information System (INIS)

    The introduction of poly(ether urethane) (PEUR) into polymer electrolyte based on poly(ethylene oxide), LiI and I2, has significantly increased the ionic conductivity by nearly two orders of magnitudes. An increment of I−3 diffusion coefficient is also observed. All-solid-state dye-sensitized solar cells are constructed using the polymer electrolytes. It was found that PEUR incorporation has a beneficial effect on the enhancement of open circuit voltage Voc by shifting the band edge of TiO2 to a negative value. Scanning electron microscope images indicate the perfect interfacial contact between the TiO2 electrode and the blend electrolyte

  1. Dye-sensitized solar cell with poly(acrylic acid-co-acrylonitrile)-based gel polymer electrolyte

    International Nuclear Information System (INIS)

    Highlights: ► A nontoxic, easily synthesized poly(acrylic acid-co-acrylonitrile) showed suitable transmittance for dye-sensitized solar cell. ► A cell with relatively large active area fabricated with this polymer material showed acceptable efficiency. ► The gel polymer matrix affected the charge recombination, I3− diffusion, double layer capacitance, and electron lifetime in the cell. - Abstract: A non-conducting, nontoxic poly(acrylic acid-co-acrylonitrile) (PAA) was prepared and used as a supporting matrix for the electrolyte of dye-sensitized solar cells (DSSCs). DSSCs of active area 0.80 cm × 1.10 cm fabricated with PAA, 0.5 M LiI, 0.05 M I2, 0.5 M 3-tert-butylpyridine, and 0.1 M 1-methyl-3-propylimidazolium iodide in 3-methoxypropionitrile solvent showed an average solar energy conversion efficiency of 1.61% under simulated sunlight illumination of 100 mW cm−2, AM 1.5. The effects of the gel polymer matrix on the electrochemical properties of DSSCs were studied using the electrochemical impedance spectroscopy. Relative to the non-gel reference cells, the results showed a decrease in charge recombination, ionic diffusion, and double layer capacitance and an increase in electron lifetime. These results could play an important role in determining the future direction for the development of high-performance gel polymer electrolytes.

  2. Isothermal microcalorimetry as a tool to study solid-electrolyte interphase formation in lithium-ion cells.

    Science.gov (United States)

    Hall, David S; Glazier, Stephen L; Dahn, J R

    2016-04-28

    Isothermal microcalorimetry can be used in conjunction with electrochemical measurements to study solid-electrolyte interphase (SEI) formation reactions as they occur in a Li-ion cell. The heat flow was measured in wound cells that contained no electrolyte additives and in cells prepared with four additives that are known to produce an SEI at the negative electrode surface: vinylene carbonate (VC), fluoroethylene carbonate (FEC), pyridine boron trifluoride (PBF), and prop-1-ene-1,3-sultone (PES). For VC, two distinct features in the differential capacity (dQ/dV vs. Q) plot that align with overlapping peaks in the heat flow plot do not agree with a simple one-electron reduction followed by anionic polymerization. For FEC, three distinct differential capacity and calorimetric peaks are observed. Heat flow measurements at multiple PBF concentrations show that PBF reduction does not significantly affect the reduction of EC at higher cell voltage. The total heat flow during SEI formation in PBF- and PES-containing cells match the calculated energies in recently published reaction pathways. It is concluded that IMC may be used to study the underlying chemistry of SEI formation, especially when paired with computational studies. PMID:27056253

  3. Metal/ceria water-gas shift catalysts for automotive polymer electrolyte fuel cell system

    International Nuclear Information System (INIS)

    Polymer electrolyte fuel cell (PEFC) systems are a leading candidate for replacing the internal combustion engine in light duty vehicles. One method of generating the hydrogen necessary for the PEFC is reforming a liquid fuel, such as methanol or gasoline, via partial oxidation, steam reforming, or autothermal reforming (a combination of partial oxidation and steam reforming). The H(sub 2)-rich reformate can contain as much as 10% carbon monoxide. Carbon monoxide has been shown to poison the platinum-based anode catalyst at concentrations as low as 10 ppm,1 necessitating removal of CO to this level before passing the reformate to the fuel cell stack. The water-gas shift (WGS) reaction, CO+ H(sub 2)O(rightleftharpoons) CO(sub 2)+ H(sub 2), is used to convert the bulk of the reformate CO to CO(sub 2). Industrially, the WGS reaction is conducted over two catalysts, which operate in different temperature regimes. One catalyst is a FeCr mixed oxide, which operates at 350-450 C and is termed the high-temperature shift (HTS) catalyst. The second catalyst is a CuZn mixed oxide, which operates at 200-250 C and is termed the low-temperature shift (LTS) catalyst. Although these two catalysts are used industrially in the production of H(sub 2) for ammonia synthesis, they have major drawbacks that make them unsuitable for transportation applications. Both the LTS and the HTS catalysts must first be ''activated'' before being used. For example, the copper in the copper oxide/zinc oxide LTS catalyst must first be reduced to elemental copper in situ before it becomes active for the WGS reaction. This reduction reaction is exothermic and must be carried out under well- controlled conditions using a dilute hydrogen stream (1 vol% H(sub 2)) to prevent high catalyst temperatures, which can result in sintering (agglomeration) of the copper particles and loss of active surface area for the WGS reaction. Also, once the catalyst has been activated by reduction, it must be protected from

  4. New approaches towards novel composite and multilayer membranes for intermediate temperature-polymer electrolyte fuel cells and direct methanol fuel cells

    Science.gov (United States)

    Branco, Carolina Musse; Sharma, Surbhi; de Camargo Forte, Maria Madalena; Steinberger-Wilckens, Robert

    2016-06-01

    This review analyses the current and existing literature on novel composite and multilayer membranes for Polymer Electrolyte Fuel Cell applications, including intermediate temperature polymer electrolyte fuel cell (IT-PEFC) and direct methanol fuel cell (DMFC) systems. It provides a concise scrutiny of the vast body of literature available on organic and inorganic filler based polymer membranes and links it to the new emerging trend towards novel combinations of multilayered polymer membranes for applications in DMFC and IT-PEFC. The paper carefully explores the advantages and disadvantages of the most common preparation techniques reported for multilayered membranes such as hot-pressing, casting and dip-coating and also summarises various other fresh and unique techniques employed for multilayer membrane preparation.

  5. Mass and charge transfer on various relevant scales in polymer electrolyte fuel cells[Dissertation 16991

    Energy Technology Data Exchange (ETDEWEB)

    Freunberger, S. A.

    2007-07-01

    This dissertation is concerned with the development, experimental diagnostics and mathematical modelling and simulation of polymer electrolyte fuel cells (PEFC). The central themes throughout this thesis are the closely interlinked phenomena of mass and charge transfer. In the face of developing a PEFC system for vehicle propulsion these phenomena are scrutinized on a broad range of relevant scales. Starting from the material related level of the membrane and the gas diffusion layer (GDL) we turn to length scales, where structural features of the cell additionally come into play. These are the scale of flow channels and ribs, the single cell and the cell stack followed by the cell, stack, and system development for an automotive power train. In Chapter 3 selected fundamental material models and properties, respectively, are explored that are crucial for the mathematical modelling and simulation of PEFC, as needed in some succeeding parts of this work. First, established mathematical models for mass and charge transfer in the membrane are compared within the framework of the membrane electrode assembly (MEA), which represents the electrochemical unit. Second, reliable values for effective diffusivities in the GDLs which are vital for the simulation of gaseous mass transport are measured. Therefore, a method is developed that allows measuring this quantity both as a function of compression and direction as this is a prerequisite of sophisticated more-dimensional numerical PEFC-models. Besides the cross section of the catalyst layer (CL) mass transfer under channels and ribs is considered as a major source of losses in particular under high load operation. As up to now there have been solely non-validated theoretical investigations, in Chapter 4 an experimental method is developed that is for the first time capable of resolving the current density distribution on the this scale. For this, the electron conductors in the cell are considered as 2-dimensional shunt

  6. Performance of polymer electrolyte based on chitosan blended with poly(ethylene oxide) for plasmonic dye-sensitized solar cell

    Science.gov (United States)

    Buraidah, M. H.; Teo, L. P.; Au Yong, C. M.; Shah, Shahan; Arof, A. K.

    2016-07-01

    Chitosan and poly(ethylene oxide) powders have been mixed in different weight ratios. To each mixture, a fixed amount of ammonium iodide has been added. All mixtures have been dissolved in 1% acetic acid solution to form polymer blend electrolyte films by the solution cast technique. X-ray diffraction indicates that the polymer blend electrolytes are amorphous. Fourier transform infrared spectroscopy shows shifting of the amine, carboxamide and Csbnd Osbnd C bands to lower wavenumbers indicating the occurrence of complexation. Electrochemical impedance spectroscopy has been used to study the electrical properties of the samples. The ionic conductivity for 55 wt.% chitosan-45 wt.% NH4I electrolyte system is 3.73 × 10-7 S cm-1 at room temperature and is increased to 3.66 × 10-6 S cm-1 for the blended film (16.5 wt.% chitosan-38.5 wt.% PEO)-45 wt.% NH4I film. Dye-sensitized solar cells (DSSCs) have been fabricated by sandwiching the polymer electrolyte between the TiO2/dye photoelectrode and Pt counter electrode. DSSCs fabricated exhibits short-circuit current density (Jsc) of 2.71 mA cm-2, open circuit voltage (Voc) of 0.58 V and efficiency of 0.78% with configuration ITO/TiO2/N3 dye/(16.5 wt.% chitosan-38.5 wt.% PEO)-45 wt.% NH4I(+I2)/Pt/ITO and Jsc of 2.84 mA cm-2, Voc of 0.58 V and efficiency of 1.13% with configuration ITO/TiO2 + Ag nanoparticles/N3 dye/(16.5 wt.% chitosan-38.5 wt.% PEO)-45 wt.% NH4I(+I2)/Pt/ITO.

  7. The performance of aluminium electrolysis in cryolite based electrolytes containing LiF, KF and MgF2 in a laboratory-scale cell

    OpenAIRE

    Cui, Peng

    2015-01-01

    The electrolyte composition plays a very important role in aluminium electrolysis. Higher current efficiency and lower energy consumption can be obtained through modifying the composition of the electrolyte. The important developing trend towards aluminium reduction cells may require higher current efficiency because high current efficiency can bring huge economic and environmental benefits. It is an effective and direct method to raise current efficiency through adding some ad...

  8. The single cell of low temperature solid oxide fuel cell with sodium carbonate-SDC (samarium-doped ceria) as electrolyte and biodiesel as fuel

    Science.gov (United States)

    Rahmawati, F.; Nuryanto, A.; Nugrahaningtyas, K. D.

    2016-02-01

    In this research NSDC (composite of Na2CO3-SDC) was prepared by the sol-gel method to produce NSDC1 and also by the ceramic method to produce NSDC2. The prepared NSDC then were analyzed by XRD embedded with Le Bail refinement to study the change of characteristic peaks, their crystal structure, and their cell parameters. Meanwhile, the measurement of impedance was conducted to study the electrical conductivity of the prepared materials. A single cell was prepared by coating NSDC-L (a composite of NSDC with Li0.2Ni0.7Cu0.1O2) on both surfaces of NSDC. The NSDC-L was used as anode and cathode. The ionic conductivity of NSDC1 and NSDC2 at 400 oC are 4.1109 x 10-2 S.cm-1 and 1.6231 x 10-2 S.cm-1, respectively. Both electrolytes have ionic conductivity higher than 1 x 10-4 S.cm-1, therefore, can be categorized as good electrolyte [1]. However, the NSDC1 shows electrodeelectrolyte conduction. It indicates the existence of electronic migration from electrolyte- electrode or vice versa. Those may cause a short circuit during fuel cell operation and will reduce the fuel cell performance fastly. The single cell tests were conducted at 300, 400, 500 and 600 °C. The single fuel cell with NSDC1 and NSDC2 as electrolyte show maximum power density at 400 °C with the power density of 3.736 x 10-2 mW.cm-2 and 2.245 x 10-2 mW.cm-2, respectively.

  9. Y and Ni Co-Doped BaZrO3 as a Proton-Conducting Solid Oxide Fuel Cell Electrolyte Exhibiting Superior Power Performance

    KAUST Repository

    Shafi, Shahid P.

    2015-10-16

    The fabrication of anode supported single cells based on BaZr0.8Y0.2O3-δ (BZY20) electrolyte is challenging due to its poor sinteractive nature. The acceleration of shrinkage behavior, improved sinterability and larger grain size were achieved by the partial substitution of Zr with Ni in the BZY perovskite. Phase pure Ni-doped BZY powders of nominal compositions BaZr0.8-xY0.2NixO3-δ were synthesized up to x = 0.04 using a wet chemical combustion synthesis route. BaZr0.76Y0.2Ni0.04O3-δ (BZYNi04) exhibited adequate total conductivity and the open circuit voltage (OCV) values measured on the BZYNi04 pellet suggested lack of significant electronic contribution. The improved sinterability of BZYNi04 assisted the ease in film fabrication and this coupled with the application of an anode functional layer and a suitable cathode, PrBaCo2O5+δ (PBCO), resulted in a superior fuel cell power performance. With humidified hydrogen and static air as the fuel and oxidant, respectively, a peak power density value of 428 and 240 mW cm−2 was obtained at 700 and 600°C, respectively.

  10. Hydroxypropyl Cellulose Based Non-Volatile Gel Polymer Electrolytes for Dye-Sensitized Solar Cell Applications using 1-methyl-3-propylimidazolium iodide ionic liquid

    Science.gov (United States)

    Khanmirzaei, Mohammad Hassan; Ramesh, S.; Ramesh, K.

    2015-12-01

    Gel polymer electrolytes using imidazolium based ionic liquids have attracted much attention in dye-sensitized solar cell applications. Hydroxypropyl cellulose (HPC), sodium iodide (NaI), 1-methyl-3-propylimidazolium iodide (MPII) as ionic liquid (IL), ethylene carbonate (EC) and propylene carbonate (PC) are used for preparation of non-volatile gel polymer electrolyte (GPE) system (HPC:EC:PC:NaI:MPII) for dye-sensitized solar cell (DSSC) applications. The highest ionic conductivity of 7.37 × 10-3 S cm-1 is achieved after introducing 100% of MPII with respect to the weight of HPC. Temperature-dependent ionic conductivity of gel polymer electrolytes is studied in this work. XRD patterns of gel polymer electrolytes are studied to confirm complexation between HPC polymer, NaI and MPII. Thermal behavior of the GPEs is studied using simultaneous thermal analyzer (STA) and differential scanning calorimetry (DSC). DSSCs are fabricated using gel polymer electrolytes and J-V centeracteristics of fabricated dye sensitized solar cells were analyzed. The gel polymer electrolyte with 100 wt.% of MPII ionic liquid shows the best performance and energy conversion efficiency of 5.79%, with short-circuit current density, open-circuit voltage and fill factor of 13.73 mA cm-2, 610 mV and 69.1%, respectively.

  11. Testing of a De Nora polymer electrolyte fuel cell stack of 1 kW for naval applications

    Science.gov (United States)

    Schmal, D.; Kluiters, C. E.; Barendregt, I. P.

    In a previous study calculations were carried out for a navy frigate with respect to the energy consumption of a propulsion/electricity generation system based on fuel cells. The fuel consumption for the 'all-fuel cell' ship was compared with the consumption of the current propulsion/electricity generation system based on gas turbines and diesel engines; it showed potential energy savings of a fuel cell based system amounting from 25 to 30%. On the basis of these results and taking into account various military aspects it was decided to start tests with a polymer electrolyte fuel cell (PEFC) stack. For this purpose a De Nora 1 kW PEFC was chosen. Results of the first tests after installation are satisfying.

  12. Biopolymer electrolytes based on blend of kappa-carrageenan and cellulose derivatives for potential application in dye sensitized solar cell

    International Nuclear Information System (INIS)

    In this work, carboxymethyl kappa-carrageenan was used as the principle host for developing new biopolymer electrolytes based on the blend of carboxymethyl kappa-carrageenan/carboxymethyl cellulose. The blending of carboxymethyl cellulose into carboxymethyl kappa-carragenan was found to be a promising strategy to improve the material properties such as conductive properties. The electrolyte samples were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, dynamic mechanical analysis, electrochemical impedance spectroscopy, ionic transference number measurement and linear sweep voltammetry in order to investigate their structural, thermal and electrochemical properties. Impedance study showed that the ionic conductivity increased with the increment of ammonium iodide concentration. The highest room temperature ionic conductivity achieved was 2.41 × 10−3 S cm−1 at 30 wt% of the salt. The increment of conductivity was due to the increase of formation of transient cross-linking between the carboxymethyl kappa-carrageenan/carboxymethyl cellulose chains and the doping salt as indicated the Tg trend. The conductivity was also attributed by the increase in the number of charge carriers in the biopolymer electrolytes system. The interactions between polymers and salt were confirmed by FTIR study. The transference number measurements showed that the conductivity was predominantly ionic. Temperature dependent conductivity study showed that conductivity increased with the reciprocal of temperature. The conductivity-temperature plots suggested that the conductivity obeyed the Vogel–Tammann–Fulcher relation and the activation energy for the best conducting sample was 0.010 eV. This system was used for the fabrication of dye sensitized solar cells, FTO/TiO2-dye/CMKC/CMCE-NH4I + I2/Pt. The fabricated cell showed response under light intensity of 100 mW cm−2 with efficiency of 0.13% indicating that the blend biopolymer system has

  13. Poly(cyclohexadiene)-Based Polymer Electrolyte Membranes for Fuel Cell Applications

    Energy Technology Data Exchange (ETDEWEB)

    Mays, Jimmy W.

    2011-03-07

    The goal of this research project was to create and develop fuel cell membranes having high proton conductivity at high temperatures and high chemical and mechanical durability. Poly(1,3-cyclohexadiene) (PCHD) is of interest as an alternative polymer electrolyte membrane (PEM) material due to its ring-like structure which is expected to impart superior mechanical and thermal properties, and due to the fact that PCHD can readily be incorporated into a range of homopolymer and copolymer structures. PCHD can be aromatized, sulfonated, or fluorinated, allowing for tuning of key performance structure and properties. These factors include good proton transport, hydrophilicity, permeability (including fuel gas impermeability), good mechanical properties, morphology, thermal stability, crystallinity, and cost. The basic building block, 1,3-cyclohexadiene, is a hydrocarbon monomer that could be inexpensively produced on a commercial scale (pricing typical of other hydrocarbon monomers). Optimal material properties will result in novel low cost PEM membranes engineered for high conductivity at elevated temperatures and low relative humidities, as well as good performance and durability. The primary objectives of this project were: (1) To design, synthesize and characterize new non-Nafion PEM materials that conduct protons at low (25-50%) RH and at temperatures ranging from room temperature to 120 C; and (2) To achieve these objectives, a range of homopolymer and copolymer materials incorporating poly(cyclohexadiene) (PCHD) will be synthesized, derivatized, and characterized. These two objectives have been achieved. Sulfonated and crosslinked PCHD homopolymer membranes exhibit proton conductivities similar to Nafion in the mid-RH range, are superior to Nafion at higher RH, but are poorer than Nafion at RH < 50%. Thus to further improve proton conductivity, particularly at low RH, poly(ethylene glycol) (PEG) was incorporated into the membrane by blending and by

  14. Obtaining of ceria - samaria - gadolinia ceramics for application as solid oxide fuel cell (SOFC) electrolyte

    International Nuclear Information System (INIS)

    Cerium oxide (CeO2) when doped with rare earth oxides has its ionic conductivity enhanced, enabling its use as electrolyte for Intermediate Temperature Solid Oxide Fuel Cell (IT-SOFC), which is operated in temperatures between 500 e 700 degree C. The most effective additives or dopants for ionic conductivity improvement are (samarium oxide - Sm2O3) and gadolinia (gadolinium oxide - Gd2O3), fixing the concentration between 10 and 20 molar%. In this work, Ce0,8(SmGd)0,2O1,9 powders have been synthesized by hydroxide, carbonate and oxalate coprecipitation routes. The hydrothermal treatment has been studied for powders precipitated with ammonium hydroxide. A concentrate of rare earths containing 90wt% of CeO2 and other containing 51% of Sm2O3 and 30% of Gd2O3, both prepared from monazite processing, were used as starting materials. These concentrates were used due the lower cost compared to pure commercial materials and the chemical similarity of others rare earth elements. Initially, the coprecipitation and calcination conditions were defined. The process efficiency was verified by ceramic sinterability evaluation. The results showed that powders calcined in the range of 450 and 800 degree C presented high specific surface area (90 - 150 m2.g-1) and fluorite cubic structure, indicating the solid solution formation. It was observed, by scanning electron microscopy, that morphology of particles and agglomerates is a function of precipitant agent. The dilatometric analysis indicated the higher rate of shrinkage at temperatures around 1300-1350 degree C. High densification values (>95% TD) was obtained at temperatures above 1400 degree C. Synthesis by hydroxides coprecipitation followed by hydrothermal treatment demonstrated to be a promising route for crystallization of ceria nano powders at low temperatures (200 degree C). High values of specific surface area were reached with the employment of hydrothermal treatment (about 100 m2.g-1). High density ceramics were

  15. Lowering the platinum loading of high temperature polymer electrolyte membrane fuel cells with acid doped polybenzimidazole membranes

    DEFF Research Database (Denmark)

    Fernandez, Santiago Martin; Li, Qingfeng; Jensen, Jens Oluf

    2015-01-01

    Membrane electrode assemblies (MEAs) with ultra-low Pt loading electrodes were prepared for high temperature polymer electrolyte membrane fuel cells (HT-PEMFCs) based on acid doped polybenzimidazole. With no electrode binders or ionomers, the triple phase boundary of the catalyst layer was...... established by the acid transfer from the acid doped membrane to the electrodes and can therefore be tailored by using catalysts with varied Pt to C ratios. With a loading of ca. 0.1 mgPtcm-2 on each electrode the best performance was obtained with electrodes prepared from 10 wt.% Pt/C due to the improved Pt...

  16. Method of oxygen/metal ratio determination in uranium-gadolinium fuel oxides by means of solid electrolyte galvanic cell

    International Nuclear Information System (INIS)

    Nondestructive method for determining the oxygen/metal (O/M) ratio in uranium-gadolinium fueld oxides by means of a solid-electrolyte galvanic cell (SEC) is described. The calibration dependences of the SEC emf on the O/M ratiuo are given. Factors are discussed which affect the error of determination of the O/M ratio ny the emf method in an oxide nuclear fuel. It is shown that the proposed method permits to determine the O/M ratio in uranium-gadolinium oxides with the error not more than +- 0.001 unit of O/M

  17. An electrochemical treatment to improve corrosion and contact resistance of stainless steel bipolar plates used in polymer electrolyte fuel cells

    Science.gov (United States)

    Gabreab, Ebrahim M.; Hinds, Gareth; Fearn, Sarah; Hodgson, David; Millichamp, Jason; Shearing, Paul R.; Brett, Daniel J. L.

    2014-01-01

    An electrochemical surface treatment is presented that improves the properties of stainless steel (316SS) used as bipolar plates for polymer electrolyte fuel cells (PEFCs). The process is an anodic treatment, whereby the material is polarised beyond the transpassive region. Potentiodynamic corrosion testing, chemical and morphological surface characterisation and interfacial contact resistance measurements indicate that the improved properties of 316SS are primarily a consequence of an enrichment of Cr at the near-surface of the material. The surface treatment increases the corrosion resistance and significantly reduces interfacial contact resistance.

  18. A comparison of low-pressure and supercharged operation of polymer electrolyte membrane fuel cell systems for aircraft applications

    Science.gov (United States)

    Werner, C.; Preiß, G.; Gores, F.; Griebenow, M.; Heitmann, S.

    2016-08-01

    Multifunctional fuel cell systems are competitive solutions aboard future generations of civil aircraft concerning energy consumption, environmental issues, and safety reasons. The present study compares low-pressure and supercharged operation of polymer electrolyte membrane fuel cells with respect to performance and efficiency criteria. This is motivated by the challenge of pressure-dependent fuel cell operation aboard aircraft with cabin pressure varying with operating altitude. Experimental investigations of low-pressure fuel cell operation use model-based design of experiments and are complemented by numerical investigations concerning supercharged fuel cell operation. It is demonstrated that a low-pressure operation is feasible with the fuel cell device under test, but that its range of stable operation changes between both operating modes. Including an external compressor, it can be shown that the power demand for supercharging the fuel cell is about the same as the loss in power output of the fuel cell due to low-pressure operation. Furthermore, the supercharged fuel cell operation appears to be more sensitive with respect to variations in the considered independent operating parameters load requirement, cathode stoichiometric ratio, and cooling temperature. The results indicate that a pressure-dependent self-humidification control might be able to exploit the potential of low-pressure fuel cell operation for aircraft applications to the best advantage.

  19. 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.

  20. Measurement of the mass of mercury in electrolytic cells of Chemical Industry of the Istmo s. a. of c. v. Coatzacoalcos Plant, Ver. (Mexico)

    International Nuclear Information System (INIS)

    For the industry of the production of caustic soda and chlorine is commonly use electrolytic cells with mobile electrode of mercury; in the process it gets lost mass, and there is necessity to know the quantity of mercury that exists in each cell. To know the periodic levels of mercury in the 40 electrolytic cells of the Plant of Coatzacoalcos, in the State of Veracruz (Mexico), the investigators of the ININ used the technique of isotopic dilution by mean of the radioactive injection of a radioactive tracer.(Author)

  1. Experimental analyses of low humidity operation properties of SiO2-containing catalyst layers for polymer electrolyte fuel cells

    International Nuclear Information System (INIS)

    Highlights: ► We examine SiO2-containing catalyst layers for PEFCs operated under low humidity. ► SiO2 addition led to decreased ohmic resistance due to increased water content. ► Pt utilization increased due to the increase in the σH in the electrolyte binder. ► The specific adsorption of sulfonate groups in the binder on Pt was suppressed. ► SiO2 addition promoted the back-diffusion of water generated at the cathode to anode. -- Abstract: Electrochemical operation properties of SiO2-containing catalyst layers (SiO2-CLs) under low humidity were clarified experimentally in a polymer electrolyte fuel cell (PEFC). The mass activities at 0.85 V and current densities at 0.7 V increased with increasing SiO2 content below 53% RH at 80 °C. The use of SiO2-CLs led to decreased ohmic resistance due to increased water content. It was found that such an increase in water content in the SiO2-CLs increased the electrochemically active surface area (ECA) of the Pt catalyst, due to enhancement of the proton-conducting network in the electrolyte binder, and suppressed the specific adsorption of sulfonate anions on the Pt surface. It was also clarified that the SiO2 addition in the CL promoted the back-diffusion of water generated at the cathode to the anode, resulting in an increased O2 gas diffusion rate to the cathode-CL/PEM interface, accompanied by an increased water content in the membrane. All of these factors greatly contributed to improve the cell performance under low humidity

  2. In-Situ Anomalous Small-Angle X-ray Scattering Studies of Polymer Electrolyte Membrane Fuel Cell Catalyst Degradation

    Science.gov (United States)

    Gilbert, James Andrew

    Polymer electrolyte membrane fuel cells (PEMFCs) are a promising high efficiency energy conversion technology, but their cost effective implementation, especially for automotive power, has been hindered by degradation of the electrochemically-active surface area (ECA) of the Pt nanoparticle electrocatalysts. While numerous studies using ex-situ post-mortem techniques have provided insight into the effect of operating conditions on ECA loss, the governing mechanisms and underlying processes are not fully understood. Toward the goal of elucidating the electrocatalyst degradation mechanisms, we have followed particle size distribution (PSD) growth evolutions of Pt and Pt-alloy nanoparticle catalysts during potential cycling in an aqueous acidic environment (with and without flow of electrolyte) and in a fuel cell environment using in-situ anomalous small-angle X-ray scattering (ASAXS). The results of this thesis show a surface area loss mechanism of Pt nanoparticles supported on carbon to be predominantly controlled by Pt dissolution, the particle size dependence of Pt dissolution, the loss of dissolved Pt into the membrane and electrolyte, and, to a lesser extent, the re-deposition of dissolved Pt onto larger particles. The relative extent of these loss mechanisms are shown to be dependent on the environment, the temperature, and the potential cycling conditions. Correlation of ASAXS-determined particle growth with both calculated and voltammetrically-determined oxide coverages demonstrates that the oxide coverage is playing a key role in the dissolution process and in the corresponding growth of the mean Pt nanoparticle size and loss of ECA. This understanding potentially reduces the complex changes in PSDs and ECA resulting from various voltage profiles to the response to a single variable, oxide coverage. A better understanding of the degradation mechanisms of Pt and Pt-alloy nanoparticle distributions could lead to more stable electrocatalysts while

  3. Electrolyte Concentration Effect of a Photoelectrochemical Cell Consisting of TiO2 Nanotube Anode

    OpenAIRE

    Kai Ren; Gan, Yong X.; Efstratios Nikolaidis; Sharaf Al Sofyani; Lihua Zhang

    2013-01-01

    The photoelectrochemical responses of a TiO2 nanotube anode in ethylene glycol (EG), glycerol, ammonia, ethanol, urea, and Na2S electrolytes with different concentrations were investigated. The TiO2 nanotube anode was highly efficient in photoelectrocatalysis in these solutions under UV light illumination. The photocurrent density is obviously affected by the concentration change. Na2S generated the highest photocurrent density at 0, 1, and 2 V bias voltages, but its concentration does not si...

  4. Glass Frit Dissolution Influenced by Material Composition and the Water Content in Iodide/Triiodide Electrolyte of Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Katrine Flarup Jensen

    2013-01-01

    Full Text Available To ensure long-term stable dye-sensitized solar cells (DSCs and modules, a hermetic sealing is required. This research investigates the chemical stability of I-/I3- redox electrolyte and four different glass frits (GFs. Sintered GF layers were openly exposed to nonaqueous redox electrolyte and redox electrolyte with 1, 5, and 10 wt% H2O in thin, encapsulated cells. The change in I3− absorbance was assigned to a reaction between the GF and I-/I3- electrolyte and was used to evaluate the chemical stability of the different GFs. The I3− absorbance change was monitored over 100 days. Two out of the four GFs were unstable when H2O was added to the redox electrolyte. The H2O caused metal ion leaching which was determined from EDX analysis of the inorganic remains of electrolyte samples. A GF based on Bi2O3–SiO2–B2O3 with low bond strength leached bismuth into electrolyte and formed the BiI3- complex. A ZnO–SiO2–Al2O3-based GF also became unstable when H2O was added to the redox electrolyte. Leaching of zinc ions due to exchange with H+ resulted in the formation of a zinc-iodine compound which caused I3− depletion. By applying the test design to different types of GFs, the material suitability in the DSC working environment was investigated.

  5. Improvement of ionic conductivity and performance of quasi-solid-state dye sensitized solar cell using PEO/PMMA gel electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Aram, E. [Iran Polymer and Petrochemical Institute, 14965/115 Tehran (Iran, Islamic Republic of); Ehsani, M., E-mail: m.ehsani@ippi.ac.ir [Iran Polymer and Petrochemical Institute, 14965/115 Tehran (Iran, Islamic Republic of); Khonakdar, H.A. [Iran Polymer and Petrochemical Institute, 14965/115 Tehran (Iran, Islamic Republic of); Leibniz Institute of Polymer Research, D-01067 Dresden (Germany)

    2015-09-10

    Graphical abstract: Reduced interfacial resistance of a quasi-solid-state dye sensitized solar cell with PEO/PMMA blend gel electrolytes. - Highlights: • A new polymer gel electrolyte containing PEO/PMMA was developed for DSSCs. • Optimization of polymer gel electrolyte was done for dye sensitized solar cell. • The best ionic conductivity was found in PEO/PMMA blend with 10/90 w/w composition. • The DSSC with the PEO/PMMA based electrolyte showed good photovoltaic performance. • Significant stability improvement for quasi-solid state DSSC was obtained. - Abstract: Polymer blend gel electrolytes based on polyethylene oxide (PEO) and poly(methyl methacrylate) (PMMA) as host polymers with various weight ratios, LiI/I{sub 2} as redox couple in electrolyte and 4-tert-butyl pyridine as additive were prepared by solution method. The introduction of PMMA in the PEO gel electrolyte reduced the degree of crystallinity of PEO, which was confirmed by differential scanning calorimetry (DSC). Complexation and ionic conductivity as a function of temperature were investigated with Fourier transform infrared and ionic conductometry, respectively. A good correlation was found between the degree of crystallinity and ionic conductivity. The reduction in crystallinity, governed by blending ratio, led to improvement of ionic conductivity. The best ionic conductivity was attained in PEO/PMMA blend with 10/90 w/w composition. The performance of a quasi-solid-state dye sensitized solar cell using the optimized polymer gel electrolyte was investigated. The optimized system of high ionic conductivity of 7 mS cm{sup −1}, with fill factor of 0.59, short-circuit density of 11.11 mA cm{sup −2}, open-circuit voltage of 0.75 V and the conversion efficiency of 4.9% under air mass 1.5 irradiation (100 mW cm{sup −2}) was obtained. The long-term stability of the dye-sensitized solar cell (DSSC) during 600 h was improved by using PEO/PMMA gel electrolyte relative to a liquid type

  6. Improvement of ionic conductivity and performance of quasi-solid-state dye sensitized solar cell using PEO/PMMA gel electrolyte

    International Nuclear Information System (INIS)

    Graphical abstract: Reduced interfacial resistance of a quasi-solid-state dye sensitized solar cell with PEO/PMMA blend gel electrolytes. - Highlights: • A new polymer gel electrolyte containing PEO/PMMA was developed for DSSCs. • Optimization of polymer gel electrolyte was done for dye sensitized solar cell. • The best ionic conductivity was found in PEO/PMMA blend with 10/90 w/w composition. • The DSSC with the PEO/PMMA based electrolyte showed good photovoltaic performance. • Significant stability improvement for quasi-solid state DSSC was obtained. - Abstract: Polymer blend gel electrolytes based on polyethylene oxide (PEO) and poly(methyl methacrylate) (PMMA) as host polymers with various weight ratios, LiI/I2 as redox couple in electrolyte and 4-tert-butyl pyridine as additive were prepared by solution method. The introduction of PMMA in the PEO gel electrolyte reduced the degree of crystallinity of PEO, which was confirmed by differential scanning calorimetry (DSC). Complexation and ionic conductivity as a function of temperature were investigated with Fourier transform infrared and ionic conductometry, respectively. A good correlation was found between the degree of crystallinity and ionic conductivity. The reduction in crystallinity, governed by blending ratio, led to improvement of ionic conductivity. The best ionic conductivity was attained in PEO/PMMA blend with 10/90 w/w composition. The performance of a quasi-solid-state dye sensitized solar cell using the optimized polymer gel electrolyte was investigated. The optimized system of high ionic conductivity of 7 mS cm−1, with fill factor of 0.59, short-circuit density of 11.11 mA cm−2, open-circuit voltage of 0.75 V and the conversion efficiency of 4.9% under air mass 1.5 irradiation (100 mW cm−2) was obtained. The long-term stability of the dye-sensitized solar cell (DSSC) during 600 h was improved by using PEO/PMMA gel electrolyte relative to a liquid type electrolyte

  7. Surface Reactivity of a Carbonaceous Cathode in a Lithium Triflate/Ether Electrolyte-Based Li-O2 Cell.

    Science.gov (United States)

    Carboni, Marco; Brutti, Sergio; Marrani, Andrea G

    2015-10-01

    Li-O2 batteries are currently one of the most advanced and challenging electrochemical systems with the potential to largely overcome the performances of any existing technology for energy storage and conversion. However, these optimistic expectations are frustrated by the still inadequate understanding of the fundamentals of the electrochemical/chemical reactions occurring at the cathode side, as well as within the electrolyte and at the three-phase interface. In this work, we illustrate the evolution of the morphology and composition of a carbonaceous cathode in the first discharge/charge in a Li-O2 cell with an ether-based electrolyte by X-ray photoemission spectroscopy, Fourier transform infrared spectroscopy, and transmission electron microscopy. Experiments have been carried out ex situ on electrodes recuperated from electrochemical cells stopped at various stages of galvanostatic discharge and charge. Apparently, a reversible accumulation and decomposition of organic and inorganic precipitates occurs upon discharge and charge, respectively. These precipitations and decompositions are likely driven by electrochemical and chemical parasitic processes due to the reactivity of the cathode carbonaceous matrix. PMID:26375042

  8. Nb doped TiO2 as a Cathode Catalyst Support Material for Polymer Electrolyte Membrane Fuel Cells

    Science.gov (United States)

    O'Toole, Alexander W.

    In order to reduce the emissions of greenhouse gases and reduce dependence on the use of fossil fuels, it is necessary to pursue alternative sources of energy. Transportation is a major contributor to the emission of greenhouse gases due to the use of fossil fuels in the internal combustion engine. To reduce emission of these pollutants into the atmosphere, research is needed to produce alternative solutions for vehicle transportation. Low temperature polymer electrolyte membrane fuel cells are energy conversion devices that provide an alternative to the internal combustion engine, however, they still have obstacles to overcome to achieve large scale implementation. T he following work presents original research with regards to the development of Nb doped TiO2 as a cathode catalyst support material for low temperature polymer electrolyte membrane fuel cells. The development of a new process to synthesize nanoparticles of Nb doped TiO2 with controlled compositions is presented as well as methods to scale up the process and optimize the synthesis for the aforementioned application. In addition to this, comparison of both electrochemical activity and durability with current state of the art Pt on high surface area carbon black (Vulcan XC-72) is investigated. Effects of the strong metal-support interaction on the electrochemical behavior of these materials is also observed and discussed.

  9. Effect of pyridine in electrolyte on the current-voltage characteristics in dye-sensitized solar cells

    International Nuclear Information System (INIS)

    This study aimed to investigate the effect of pyridine in electrolyte on the photocurrent density-photovoltage (J-V) characteristics in dye-sensitized solar cells. When the concentration of pyridine (cp) in an electrolyte (0.1 M LiI and 0.05 M I2 in acetonitrile) is increased from 0 to 0.4 M, the open-circuit voltage (Voc) increased by 0.14 V, whereas the short-circuit photocurrent density (Jsc) decreased by 3.0 mA cm-2. The optimum cp for the maximum cell performance was around 0.1-0.2 M. The model calculation predicted that by increasing cp from 0 to 0.4 M, the electron diffusion coefficient (D) decreases by more than one order of magnitude and the lifetime of conduction band-free electrons (τ) increases by more than one order of magnitude, implying that the electron diffusion length (L=√(Dτ)) increases by 31%, whereas the electron injection flux from dye molecules to TiO2 nanoporous films (Φ) decreases by 28%.

  10. Influence of iodine concentration on the photoelectrochemical performance of dye-sensitized solar cells containing non-volatile electrolyte

    International Nuclear Information System (INIS)

    The effect of iodine concentration in the electrolyte with non-volatile solvent of dye-sensitized solar cells (DSCs) on photovoltaic performance was studied. The electron transport and interfacial recombination kinetics were also systematically investigated by electron impedance spectroscopy (EIS). With the iodine concentration increased from 0.025 to 0.1 M, open-circuit voltage (Voc) and photocurrent density (Jsc) decreased while fill factor (ff) increased significantly. The decline of the Voc and Jsc was mainly ascribed to increased electron recombination with tri-iodide ions (I3-). The increased fill factor was primarily brought by a decrease in the total resistance. From impedance spectra of the solar cells, it can be concluded that increasing the iodine concentration in electrolytes could decrease charge transfer resistance (Rct) and the chemical capacitance (Cμ), increase the electron transport resistance (Rt), and hence decrease the electron lifetime (τ) and the effective diffusion coefficient (Dn) of electrons in the TiO2 semiconductor. With optimum iodine concentration, device showed a photocurrent density of 16.19 mA cm-2, an open-circuit voltage of 0.765 V, a fill factor of 0.66, and an overall photo-energy conversion efficiency of 8.15% at standard AM 1.5 simulated sunlight (100 mW cm-2).

  11. Influence of iodine concentration on the photoelectrochemical performance of dye-sensitized solar cells containing non-volatile electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Hao Feng [State Key Laboratory of New Ceramics and Fine Processing, Department of Material Science and Engineering, Tsinghua University, Beijing 100084 (China); Lin, Hong, E-mail: Hong-lin@mail.tsinghua.edu.c [State Key Laboratory of New Ceramics and Fine Processing, Department of Material Science and Engineering, Tsinghua University, Beijing 100084 (China); Zhang Jing; Zhuang Dongtian; Liu Yizhu [State Key Laboratory of New Ceramics and Fine Processing, Department of Material Science and Engineering, Tsinghua University, Beijing 100084 (China); Li Jianbao [State Key Laboratory of New Ceramics and Fine Processing, Department of Material Science and Engineering, Tsinghua University, Beijing 100084 (China)] [Key Laboratory of Ministry of Education for Application Technology of Chemical Materials in Hainan Superior Resources, Hainan Provincial Key Laboratory of Research on Utilization of Si-Zr-Ti Resources, College of Materials Science and Chemical Engineering, Hainan University, Haikou 570228 (China)

    2010-10-01

    The effect of iodine concentration in the electrolyte with non-volatile solvent of dye-sensitized solar cells (DSCs) on photovoltaic performance was studied. The electron transport and interfacial recombination kinetics were also systematically investigated by electron impedance spectroscopy (EIS). With the iodine concentration increased from 0.025 to 0.1 M, open-circuit voltage (V{sub oc}) and photocurrent density (J{sub sc}) decreased while fill factor (ff) increased significantly. The decline of the V{sub oc} and J{sub sc} was mainly ascribed to increased electron recombination with tri-iodide ions (I{sub 3}{sup -}). The increased fill factor was primarily brought by a decrease in the total resistance. From impedance spectra of the solar cells, it can be concluded that increasing the iodine concentration in electrolytes could decrease charge transfer resistance (R{sub ct}) and the chemical capacitance (C{sub {mu}}), increase the electron transport resistance (R{sub t}), and hence decrease the electron lifetime ({tau}) and the effective diffusion coefficient (D{sub n}) of electrons in the TiO{sub 2} semiconductor. With optimum iodine concentration, device showed a photocurrent density of 16.19 mA cm{sup -2}, an open-circuit voltage of 0.765 V, a fill factor of 0.66, and an overall photo-energy conversion efficiency of 8.15% at standard AM 1.5 simulated sunlight (100 mW cm{sup -2}).

  12. PRI 3.1: Electrolyte membrane fuel cells (Co-PACEM), final report (july 2002 to june 2004); PRI 3.1: Coeurs de piles a combustible a electrolyte membrane (Co-PACEM), rapport final (juillet 2002 a juin 2004)

    Energy Technology Data Exchange (ETDEWEB)

    Lamy, C.

    2004-07-01

    The researches realized in the PRI Co-PACEM aim to improve the operating of the core of the electrolyte membrane fuel cells, at low temperature in order to minimize the high voltage of the electro-chemical reactions, to decrease the cost of the membrane, to improve the properties (conductivity, mechanical and thermal stability...) and to optimize the transport of heat and reactive. The document presents the research programs. (A.L.B.)

  13. Development of photoelectrochemical cells based on compound semiconductors and nonaqueous electrolytes. Semiannual report, May 1, 1981-October 31, 1981

    Energy Technology Data Exchange (ETDEWEB)

    Rauh, R. D.

    1982-03-01

    A reproducible procedure for chemical bath deposition (CBD) of CdSe has been documented in detail, allowing a consistent production of photoelectrode yielding 5.5 to 6.5% conversion efficiency in alkaline polysulfide electrolyte (employing a tungsten halogen lamp/KG-2 filter solar simulated light source). The CBD films of n-CdSe on Ti have achieved an efficiency of approx. 10% under both solar simulated and real sunlight conditions using an Fe(CN)/sub 6//sup -3///sup -4/ electrolyte at pH 13. For an initial current density of 16 mA/cm/sup 2/ (approx. 80 mW/cm/sup 2/ illumination), a decrease of approx. 25% is observed after 3 hours illumination. Research was completed on developing a stable Cu/sup +///sup +2/ redox electrolyte in CH/sub 3/CN, which contains excess Cl/sup -/, to promote photochemical stability. For poly-n-GaAs, best results were obtained for electrolytes containing approx. 0.5M Cucl, 0.05M CuCl/sub 2/, 1M tetrabutylammonium chloride, viz: at 80 mW/cm/sup 2/, j/sub sc/ = 19 mA/cm/sup 2/, V/sub oc/ = 0.74V, P/sub max/ = 3.78 mW/cm/sup 2/, ff = 0.27 and eta = 4.8% (eta = 8.1% at 8 mW/cm/sup 2/ irradiation). Five encapsulated sealed cells have been tested with 15 cm/sup 2/ photoelectrodes comprised of CBD CdSe on Ti. The cells are frontwall illuminated with various configurations for ion flow to the rear-placed Ni/CoS electrode. For one design, an efficiency of 4.3% was achieved under 63 mW/cm/sup 2/ real solar illumination. Laser spot scanning has been developed as a technique for evaluation of both large area geometrical effects and microscopic photoelectrode morphological effects on the performance of PECs.

  14. Proton transport in additives to the polymer electrolyte membrane for fuel cell application

    Energy Technology Data Exchange (ETDEWEB)

    Toelle, Pia

    2011-03-21

    The enhancement of proton transport in polymer electrolyte membranes is an important issue for the development of fuel cell technology. The objective is a material providing proton transport at a temperature range of 350 K to 450 K independent from a purely water based mechanism. To enhance the PEM properties of standard polymer materials, a class of additives is studied by means of atomistic simulations consisting of functionalised mesoporous silicon dioxide particles. The functional molecules are imidazole or sulphonic acid, covalently bound to the surface via a carbon chain with a surface density of about 1.0 nm{sup -2} groups. At first, the proton transport mechanism is explored in a system of functional molecules in vacuum. The molecules are constrained by the terminal carbon groups according to the geometric arrangement in the porous silicon dioxide. The proton transport mechanism is characterised by structural properties obtained from classical molecular dynamics simulations and consists of the aggregation of two or more functional groups, a barrier free proton transport between these groups followed by the separation of the groups and formation of new aggregates due to fluctuations in the hydrogen bond network and movement of the carbon chain. For the different proton conducting groups, i.e. methyl imidazole, methyl sulphonic acid and water, the barrier free proton transport and the formation of protonated bimolecular complexes were addressed by potential energy calculations of the density functional based tight binding method (DFTB). For sulphonic acid even at a temperature of 450 K, relatively stable aggregates are formed, while most imidazole groups are isolated and the hydrogen bond fluctuations are high. However, high density of groups and elevated temperatures enhance the proton transport in both systems. Besides the anchorage and the density of the groups, the influence of the chemical environment on the proton transport was studied. Therefore, the

  15. The effect of Pr co-dopant on the performance of solid oxide fuel cells with Sm-doped ceria electrolyte

    International Nuclear Information System (INIS)

    Samaria-doped ceria Ce0.9Sm0.1O1.95 (SDC) and samaria and praseodymium co-doped ceria Ce0.9Sm0.08Pr0.02O1.95 (SPDC) powders were synthesized by glycine nitrate process. SDC and SPDC electrolytes were made using the corresponding powders to press pellets and sinter them in air at 1400 deg. C. SEM and open porosity measurement showed the electrolytes were not dense and SPDC was more porous than SDC. Raman spectra indicated the oxygen vacancy concentration of SPDC was higher than SDC. Solid oxide fuel cells (SOFCs) with SPDC and SDC electrolytes were made and tested. The SOFC with SPDC electrolyte had higher power density but lower open circuit voltage. Impedance measurement was undertaken for the SOFCs at open circuit and the results showed that both the Ohmic and polarization resistances for SPDC electrolyte are smaller than for SDC. It is explained that co-doping Pr in Sm-doped ceria may increase the oxygen ionic conductivity by changing the grain boundary conditions so that more oxygen vacancies may exist and move faster. The electrochemical catalytic activity of Pr may play an important role in decreasing the polarization of electrolyte-electrode interface of the SOFCs

  16. Intermediate-temperature operation of solid oxide fuel cells (IT-SOFCs) with thin film proton conductive electrolyte

    Science.gov (United States)

    Kariya, T.; Uchiyama, K.; Tanaka, H.; Hirono, T.; Kuse, T.; Yanagimoto, K.; Henmi, M.; Hirose, M.; Kimura, I.; Suu, K.; Funakubo, H.

    2015-12-01

    A novel solid oxide fuel cell (SOFC) structure, which is fabricated on a Pd-plated porous stainless steel substrate, was proposed for low-temperature SOFC operation. The surface of the substrate was covered with Pd layer without any pores, which reduces the difficulty of depositing thin film electrolyte on the porous substrate. A 1.2-μm thick proton conductive Sr(Zr0.8Y0.2)O3-δ (SZYO) layer and the cathode of a 100-nm thick (La0.6Sr0.4)(Co0.2Fe0.8)O3-δ (LSCF) layer were deposited on the Pd-plated substrates by the pulsed laser deposition (PLD) method. The low temperature operations at 400 and 450 °C were demonstrated with proposed SOFC cells.

  17. Development and characterization of acid-doped polybenzimidazole/sulfonated polysulfone blend polymer electrolytes for fuel cells

    DEFF Research Database (Denmark)

    Hasiotis, C.; Li, Qingfeng; Deimede, V.;

    2001-01-01

    Polymeric membranes from blends of sulfonated polysulfones (SPSF) and polybenzimidazole (PBI) doped with phosphoric acid were developed as potential high-temperature polymer electrolytes for fuel cells and other electrochemical applications. The water uptake and acid doping of these polymeric...... was found to be higher than 10/sup -2/ S cm/sup -1/. Much improvement in the mechanical strength is observed for the blend polymer membranes, especially at higher temperatures. Preliminary work has demonstrated the feasibility of these polymeric membranes for fuel-cell applications...... membranes were investigated. Ionic conductivity of the membranes was measured in relation to temperature, acid doping level, sulfonation degree of SPSF, relative humidity, and blend composition. The conductivity of SPSF was of the order of 10/sup -3/ S cm/sup -1/. In the case of blends of PBI and SPSF it...

  18. Efficiency improvement by incorporating 1-methyl-3-propylimidazolium iodide ionic liquid in gel polymer electrolytes for dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Dye-sensitized solar cells (DSSCs) based on gel polymer electrolytes is a promising photovoltaic application which has been developed to solve the problem of liquid electrolyte leakage and improving the stability of the DSSCs. With the aim of replacing these liquid electrolytes for the applications of DSSCs, in this research we have prepared and optimized gel polymer electrolytes (GPE) consisting of poly[1-vinylpyrrolidone-co-vinyl acetate] (P[VP-co-VAc]), potassium iodide (KI), iodine (I2), ethylene carbonate (EC), propylene carbonate (PC) and 1-methyl-3-propylimidazolium iodide (MPIm+I−) ionic liquid. The highest ionic conductivity obtained for this system is 3.13 × 10−3 S cm−1 at room temperature. Fourier transform infrared (FTIR) studies confirmed the complexation of the P(VP-co-VAc)-based gel polymer electrolytes. These GPEs were then assembled into DSSCs with the configuration of glass/FTO/TiO2/N3 dye/electrolyte/Pt/FTO/glass. The resultant DSSCs from P(VP-co-VAc)-based conducting gel electrolytes display power conversion efficiencies of 4.67% with maximum short circuit current density (jsc) of 11.98 mA cm−2, open circuit voltage (Voc) of 0.59 V and fill factor of 66% at 15 wt.% of 1-methyl-3-propylimidazolium iodide under standard light intensity of 100 mW cm−2 irradiation of AM 1.5 sunlight. Electrochemical impedance studies of the DSSCs were conducted and results indicate that the addition of MPIm+I− increases the recombination process of the excited electron with I3− in the electrolyte which leads to shortening of the electron lifetime of the DSSCs. The electrocatalytic activity of the DSSC has also been investigated using Tafel polarization studies

  19. Performance characteristics of guanine incorporated PVDF-HFP/PEO polymer blend electrolytes with binary iodide salts for dye-sensitized solar cells

    Science.gov (United States)

    Senthil, R. A.; Theerthagiri, J.; Madhavan, J.; Arof, A. K.

    2016-08-01

    In this work, we have investigated the influence of guanine as an organic dopant in dye-sensitized solar cell (DSSC) based on poly(vinylidinefluoride-co-hexafluoropropylene) (PVDF-HFP)/polyethylene oxide (PEO) polymer blend electrolyte along with binary iodide salts (potassium iodide (KI) and tetrabutylammonium iodide (TBAI)) and iodine (I2). The PVDF-HFP/KI + TBAI/I2, PVDF-HFP/PEO/KI + TBAI/I2 and guanine incorporated PVDF-HFP/PEO/KI + TBAI/I2 electrolytes were prepared by solution casting technique using DMF as solvent. The PVDF-HFP/KI + TBAI/I2 electrolyte showed an ionic conductivity value of 9.99 × 10-5 Scm-1, whereas, it was found to be increased to 4.53 × 10-5 Scm-1 when PEO was blended with PVDF-HFP/KI + TBAI/I2 electrolyte. However, a maximum ionic conductivity value of 3.67 × 10-4 Scm-1 was obtained for guanine incorporated PVDF-HFP/PEO/KI + TBAI/I2 blend electrolyte. The photovoltaic properties of all these polymer electrolytes in DSSCs were characterized. As a consequence, the power conversion efficiency of the guanine incorporated PVDF-HFP/PEO/KI + TBAI/I2 electrolyte based DSSC was significantly improved to 4.98% compared with PVDF-HFP/PEO/KI + TBAI/I2 electrolyte based DSSC (2.46%). These results revealed that the guanine can be an effective organic dopant to enhance the performance of DSSCs.

  20. A taxonomy of apatite frameworks for the crystal chemical design of fuel cell electrolytes

    International Nuclear Information System (INIS)

    Apatite framework taxonomy succinctly rationalises the crystallographic modifications of this structural family as a function of chemical composition. Taking the neutral apatite [La8Sr2][(GeO4)6]O2 as a prototype electrolyte, this classification scheme correctly predicted that 'excess' oxygen in La9SrGe6O26.5 is tenanted in the framework as [La9Sr][(GeO4)5.5(GeO5)0.5]O2, rather than the presumptive tunnel location of [La9Sr][(GeO4)6]O2.5. The implication of this approach is that in addition to the three known apatite genera-A10(BO3)6X2, A10(BO4)6X2, A10(BO5)6X2-hybrid electrolytes of the types A10(BO3/BO4/BO5)6X2 can be designed, with potentially superior low-temperature ion conduction, mediated by the introduction of oxygen to the framework reservoir. - Graphical abstract: Apatite framework taxonomy succinctly rationalises the crystallographic modifications of this structural family as a function of chemical composition. Neutron diffraction identified that the excess oxygen in La9SrGe6O26.5 is tenanted in the framework as [La9Sr][(GeO4)5.5(GeO5)0.5]O2. The implication of this approach is that in addition to the three known apatite genera-A10(BO3)6X2, A10(BO4)6X2, A10(BO5)6X2-hybrid electrolytes of the types A10(BO3/BO4/BO5)6X2 can be designed

  1. Bilayer electrolyte-anode for solid oxide fuel cell; Obtencao de bicamadas eletrolito-anodo para pilhas a combustivel de oxido solido

    Energy Technology Data Exchange (ETDEWEB)

    Crochemore, G.B.; Marcomini, R.F.; Souza, D.P.F. de [Universidade Federal de Sao Carlos (GEMM/UFSCAR), Sao Carlos, SP (Brazil). Programa de Pos Graduacao em Ciencia e Engenharia de Materiais], Email: dulcina@ufscar.br; Rabelo, A.A. [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Fac. de Engenharia de Materiais

    2010-07-01

    Solid oxide fuel cell is a high efficient device hence it plays a very important role in the hydrogen economy. However, the cell operation temperature must be lower than 800 deg C, what is attainable for thin Yttria stabilized zirconia (YSZ) electrolytes. The tape casting process is the most used technique because it allows a very fine tuning of the tape thickness. In this work it were investigated the processing conditions for obtaining electrolyte-anode (YSZ/ YSZ-NiO) bilayers with no lamination after the sintering process. (author)

  2. Polymer electrolytes

    Czech Academy of Sciences Publication Activity Database

    Abbrent, Sabina; Greenbaum, S.; Peled, E.; Golodnitsky, D.

    Singapore: World Scientific Publishing, 2015 - (Dudney, N.; West, W.; Nanda, J.), s. 523-589 ISBN 978-981-4651-89-9 Institutional support: RVO:61389013 Keywords : polymer electrolytes * applications * mesuring techniques Subject RIV: CD - Macromolecular Chemistry

  3. Yttria-doped zirconia as solid electrolyte for fuel-cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Butz, Benjamin

    2009-11-27

    7.3-10 mol% yttria-doped zirconia (YDZ) was studied with emphasis on its long-term stability as solid electrolyte. The decomposition of common 8.5YDZ (950 C) was detected by analytical TEM. As second issue, the microstructural and chemical properties of nanocrystalline 7.3YDZ thin films were investigated. Metastable t''-YDZ was found to precipitate in nanoscaled regions in YDZ up to 10 mol% yttria. Furthermore, a revised boundary of the c+t phase field, in which YDZ decomposes, is presented. (orig.)

  4. Ionic conductivity measurement in magnesium aluminate spinel and solid state galvanic cell with magnesium aluminate electrolyte

    Science.gov (United States)

    Lee, Myongjai

    This thesis work is about the experimental measurement of electronic and ionic conductivities in the MgAl2O4 spinel at 500˜600°C range and exploring the fundamental origin of solid-state galvanic cell behavior in the cell of Al|MgAl2O4|Mg, Al|MgAl2O 4|C, and Mg|MgAl2O4|C, in which at least one metal electrode in common with the composition of the electrolyte. For the electronic conductivity measurement, we have used the ion-blocking Gold and Carbon electrodes which are inert with both Mg and Al ions to suppress the ionic conduction from the total conduction. DC polarization method was used to measure the conduction through Au|MgAl2O4|Au and C|MgAl2O4|C specimens. The measured electrical conductivity using Au|MgAl2O4|Au and C|MgAl2O4|C specimens showed 10-9.3 ˜ 10-8.4 (O·cm) -1 at 600˜720°C range following the Arrhenius-type relation. These conductivity data are in agreement with reported data obtained from Pt and Ag ion-blocking electrodes deposited on MgAl2O4 specimens. For the ionic conductivity measurement, we have used the non-blocking Al and Mg electrodes for Al and Mg ionic conductivities, respectively. Ionic conductivity measurement of Al and Mg in separate manner has not been reported yet. In both Al|MgAl2O4|Al and Mg|MgAl2O 4|Mg specimens, gradual increase of conduction was observed once at the initial period before it reaches the steady state conduction. By DC method on the range of 580˜650°C, steady state Al ionic conductivity was measured from Al|MgAl2O4|Al specimen showing 10 -7.7 ˜ 10-6.8 (O·cm)-1 with the activation energy of 1.9eV in sigma = sigma0 exp-QRT formula. There was no difference in the conductivity by the change of the atmosphere from 5%H2 + 95%N2 mixed gas to pure Ar gas. So it was confirmed that the oxygen defect chemistry did not play a role. For Mg ionic conductivity Mg|MgAl2O4|Mg specimen was used and the measured conductivity shows 10-6.7 ˜ 10-4.4 (O·cm)-1 at 400˜550°C with the activation energy of 1.44eV at Ar gas

  5. Improved performance of solid oxide fuel cell with pulsed laser deposited thin film ceria–zirconia bilayer electrolytes on modified anode substrate

    International Nuclear Information System (INIS)

    Highlights: ► Fabricate thin film YSZ/SDC bilayer electrolytes SOFCs by pulsed laser deposition. ► The thin YSZ layer blocks electronic current in SDC layer. ► The bilayer cell retains the chemical, mechanical and structural integrity. ► The electrochemical performance and OCVs of the cell have been improved. -- Abstract: Bilayer electrolytes composed of an yttria stabilized zirconia (YSZ) layer (∼2 μm) and a samaria doped ceria (SDC) layer (∼6 μm) have been successfully fabricated by pulsed laser deposition (PLD) technique at 600 °C for thin film solid oxide fuel cells (SOFCs). A NiO-YSZ (60:40 wt.% with 10 wt.% starch) anode supported YSZ/SDC bilayer electrolytes cell with Sm0.5Sr0.5CoO3−δ-Ce0.8Sm0.2O2−δ (SSC-SDC, 70:30 wt.%) cathode was tested, yielding open circuit voltage (OCV) value of 0.843 V and maximum power density of 0.87 W cm−2 at 700 °C. With a NiO-YSZ anode functional layer (50:50 wt.%) introduced into anode/electrolyte interface, significantly enhanced cell performance was achieved, i.e., the cell OCV of 0.959 V and 0.98 V with maximum power density of 1.19 W cm−2 and 1.08 W cm−2 at 750 °C and 700 °C, respectively. The electrical current leakage in the SDC single layer cell caused by the reduction of Ce4+ to Ce3+ in reducing environment has been eliminated by depositing the YSZ thin film as a blocking layer. Characterization analysis of the cell showed that the bilayer electrolyte deposited by PLD technique have retained the chemical, mechanical and structural integrity of the cell

  6. Improved Durability of Electrocatalyst Based on Coating of Carbon Black with Polybenzimidazole and their Application in Polymer Electrolyte Fuel Cells.

    Science.gov (United States)

    Fujigaya, Tsuyohiko; Hirata, Shinsuke; Berber, Mohamed R; Nakashima, Naotoshi

    2016-06-15

    Improvement of durability of the electrocatalyst has been the key issue to be solved for the practical application of polymer electrolyte membrane fuel cells. One of the promising strategies to improve the durability is to enhance the oxidation stability of the carbon-supporting materials. In this report, we describe in detail the mechanism of the stability improvement of carbon blacks (CBs; Vulcan and Ketjen) by coating with polybenzimidazole (PBI). Nitrogen adsorption experiments reveal that the PBI coating of CBs results in the capping of the gates of the CB-micropores by the PBI. Since the surface of the micropores inside the CBs are inherently highly oxidized, the capping of such pores effectively prevents the penetration of the electrolyte into the pore and works to avoid the further oxidation of interior of the micropore, which is proved by cyclic voltammogram measurements. Above mechanism agrees very well with the dramatic enhancement of the durability of the membrane electrode assembly fabricated using Pt on the PBI-coated CBs as an electrocatalyst compared to the conventional Pt/CB (PBI-non coated) catalyst. PMID:27227977

  7. Nanocomposite semi-solid redox ionic liquid electrolytes with enhanced charge-transport capabilities for dye-sensitized solar cells.

    Science.gov (United States)

    Rutkowska, Iwona A; Marszalek, Magdalena; Orlowska, Justyna; Ozimek, Weronika; Zakeeruddin, Shaik M; Kulesza, Pawel J; Grätzel, Michael

    2015-08-10

    The ability of Pt nanostructures to induce the splitting of the II bond in iodine (triiodide) molecules is explored here to enhance electron transfer in the iodine/iodide redox couple. Following the dispersal of Pt nanoparticles at 2 % (weight) level, charge transport was accelerated in triiodide/iodide-containing 1,3-dialkylimidazolium room-temperature ionic liquid. If both Pt nanoparticles and multi-walled carbon nanotubes were introduced into the ionic-liquid-based system, a solid-type (nonfluid) electrolyte was obtained. By using solid-state voltammetric (both sandwich-type and microelectrode-based) methodology, the apparent diffusion coefficients for charge transport increased to approximately 1×10(-6)  cm(2)  s(-1) upon the incorporation of the carbon-nanotube-supported iodine-modified Pt nanostructures. A dye-sensitized solar cell comprising TiO2 covered with a heteroleptic Ru(II) -type sensitizer (dye) and the semisolid triiodide/iodide ionic liquid electrolyte admixed with carbon-nanotube-supported Pt nanostructures yielded somewhat higher power conversion efficiencies (up to 7.9 % under standard reporting conditions) than those of the analogous Pt-free system. PMID:26119519

  8. Development of nano-structure controlled polymer electrolyte fuel-cell membranes by high-energy heavy ion irradiation

    International Nuclear Information System (INIS)

    There is increasing interest in polymer electrolyte fuel cells (PEFCs) together with recent worldwide energy demand and environmental issues. In order to develop proton-conductive membranes for PEFCs, we have been using high-energy heavy ion beams from the cyclotron accelerator of Takasaki Ion Accelerators for Advanced Radiation Application (TIARA), JAEA. Our strategic focus is centered on using nano-scale controllability of the ion-beam processing; the membrane preparation involves (1) the irradiation of commercially-available base polymer films with MeV ions, (2) graft polymerization of vinyl monomers into electronically-excited parts along the ion trajectory, called latent tracks, and (3) sulfonation of the graft polymers. Interestingly, the resulting membranes exhibited anisotropic proton transport, i.e., higher conductivity in the thickness direction. According to microscopic observations, this is probably because the columnar electrolyte phase extended, with a width of tens-to-hundreds nanometers, through the membrane. Other excellent membrane properties, e.g., sufficient mechanical strength, high dimensional stability, and low gas permeability should be due to such a controlled structure. (author)

  9. 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

  10. High temperature operation of a solid polymer electrolyte fuel cell stack based on a new ionomer membrane

    Energy Technology Data Exchange (ETDEWEB)

    Arico, A.S.; Di Blasi, A.; Brunaccini, G.; Sergi, F.; Dispenza, G.; Andaloro, L.; Ferraro, M.; Antonucci, V. [CNR-ITAE, Messina (Italy); Asher, P.; Buche, S.; Fongalland, D.; Hards, G.A.; Sharman, J.D.B. [Johnson Matthey Fuel Cells Ltd, Blounts Court, Sonning Common, Reading, Berks (United Kingdom); Bayer, A.; Heinz, G.; Zandona, N. [SolviCore GmbH and Co KG, Hanau (Germany); Zuber, R. [Umicore AG and Co KG, Dept. RD-EP, Hanau (Germany); Gebert, M.; Corasaniti, M.; Ghielmi, A. [Solvay Solexis, Bollate (Italy)

    2010-12-15

    Polymer electrolyte fuel cell stacks assembled with Johnson Matthey Fuel Cells and SolviCore MEAs based on the Aquivion trademark E79-03S short-side chain (SSC), chemically stabilised perfluorosulphonic acid membrane developed by Solvay Solexis were investigated at CNR-ITAE in the EU Sixth Framework 'Autobrane' project. Electrochemical experiments in fuel cell short stacks were performed under practical automotive operating conditions at pressures of 1-1.5 bar abs. over a wide temperature range, up to 130 C, with varying levels of humidity (down to 18% R. H.). The stacks using large area (360 cm{sup 2}) MEAs showed elevated performance in the temperature range from ambient to 100 C (cell power density in the range of 600-700 mWcm{sup -2}) with a moderate decrease above 100 C. The performances and electrical efficiencies achieved at 110 C (cell power density of about 400 mWcm{sup -2} at an average cell voltage of about 0.5-0.6 V) are promising for automotive applications. Duty-cycle and steady-state galvanostatic experiments showed excellent stack stability for operation at high temperature. A performance comparison of Aquivion trademark and Nafion trademark -based MEAs under practical operating conditions showed a significantly better capability for the Solvay Solexis membrane to sustain high temperature operation. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. 3D printed sample holder for in-operando EPR spectroscopy on high temperature polymer electrolyte fuel cells

    Science.gov (United States)

    Niemöller, Arvid; Jakes, Peter; Kayser, Steffen; Lin, Yu; Lehnert, Werner; Granwehr, Josef

    2016-08-01

    Electrochemical cells contain electrically conductive components, which causes various problems if such a cell is analyzed during operation in an EPR resonator. The optimum cell design strongly depends on the application and it is necessary to make certain compromises that need to be individually arranged. Rapid prototyping presents a straightforward option to implement a variable cell design that can be easily adapted to changing requirements. In this communication, it is demonstrated that sample containers produced by 3D printing are suitable for EPR applications, with a particular emphasis on electrochemical applications. The housing of a high temperature polymer electrolyte fuel cell (HT-PEFC) with a phosphoric acid doped polybenzimidazole membrane was prepared from polycarbonate by 3D printing. Using a custom glass Dewar, this fuel cell could be operated at temperatures up to 140 °C in a standard EPR cavity. The carbon-based gas diffusion layer showed an EPR signal with a characteristic Dysonian line shape, whose evolution could be monitored in-operando in a non-invasive manner.

  12. 3D printed sample holder for in-operando EPR spectroscopy on high temperature polymer electrolyte fuel cells.

    Science.gov (United States)

    Niemöller, Arvid; Jakes, Peter; Kayser, Steffen; Lin, Yu; Lehnert, Werner; Granwehr, Josef

    2016-08-01

    Electrochemical cells contain electrically conductive components, which causes various problems if such a cell is analyzed during operation in an EPR resonator. The optimum cell design strongly depends on the application and it is necessary to make certain compromises that need to be individually arranged. Rapid prototyping presents a straightforward option to implement a variable cell design that can be easily adapted to changing requirements. In this communication, it is demonstrated that sample containers produced by 3D printing are suitable for EPR applications, with a particular emphasis on electrochemical applications. The housing of a high temperature polymer electrolyte fuel cell (HT-PEFC) with a phosphoric acid doped polybenzimidazole membrane was prepared from polycarbonate by 3D printing. Using a custom glass Dewar, this fuel cell could be operated at temperatures up to 140°C in a standard EPR cavity. The carbon-based gas diffusion layer showed an EPR signal with a characteristic Dysonian line shape, whose evolution could be monitored in-operando in a non-invasive manner. PMID:27323280

  13. Temperature field, H{sub 2} and H{sub 2}O mass transfer in SOFC single cell: Electrode and electrolyte thickness effects

    Energy Technology Data Exchange (ETDEWEB)

    Zitouni, Bariza; Moussa, Hocine Ben; Saighi, Slimane [Laboratoire d' etude des systemes energetiques industriels (LESEI), Universite de Batna, Batna (Algeria); Oulmi, Kafia [Laboratoire de chimie et de chimie de l' environnement, Universite de Batna, Batna (Algeria); Chetehouna, Khaled [Laboratoire Energetique Explosions Structures (LEES). ENSI, Bourges (France)

    2009-06-15

    The temperature increment in electrodes and electrolyte of a fuel cell is mainly attributed to the chemical reaction and the irreversibilities. The aim of this work is to study the increasing temperature of a SOFC single cell under the influence of the electrode and electrolyte thicknesses for its type of heat source. The hydrogen and water field are also discussed according to anode thickness. The results of a self-developed mathematical model show the increasing temperature in the solid side of SOFC; anode, electrolyte and cathode by heat source types ''Joule effect'' at the several geometric configurations of SOFC. The maximum temperature value is also discussed for several cathode thicknesses under the activation polarization effect. Moreover, mass transfer for both hydrogen and water is studied according to anode thickness. (author)

  14. High-performance membrane-electrode assembly with an optimal polytetrafluoroethylene content for high-temperature polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Jeong, Gisu; Kim, MinJoong; Han, Junyoung; Kim, Hyoung-Juhn; Shul, Yong-Gun; Cho, EunAe

    2016-08-01

    Although high-temperature polymer electrolyte membrane fuel cells (HT-PEMFCs) have a high carbon monoxide tolerance and allow for efficient water management, their practical applications are limited due to their lower performance than conventional low-temperature PEMFCs. Herein, we present a high-performance membrane-electrode assembly (MEA) with an optimal polytetrafluoroethylene (PTFE) content for HT-PEMFCs. Low or excess PTFE content in the electrode leads to an inefficient electrolyte distribution or severe catalyst agglomeration, respectively, which hinder the formation of triple phase boundaries in the electrodes and result in low performance. MEAs with PTFE content of 20 wt% have an optimal pore structure for the efficient formation of electrolyte/catalyst interfaces and gas channels, which leads to high cell performance of approximately 0.5 A cm-2 at 0.6 V.

  15. Effect of the alkaline cation size on the conductivity in gel polymer electrolytes and their influence on photo electrochemical solar cells.

    Science.gov (United States)

    Bandara, T M W J; Fernando, H D N S; Furlani, M; Albinsson, I; Dissanayake, M A K L; Ratnasekera, J L; Mellander, B-E

    2016-04-20

    The nature and concentration of cationic species in the electrolyte exert a profound influence on the efficiency of nanocrystalline dye-sensitized solar cells (DSSCs). A series of DSSCs based on gel electrolytes containing five alkali iodide salts (LiI, NaI, KI, RbI and CsI) and polyacrylonitrile with plasticizers were fabricated and studied, in order to investigate the dependence of solar cell performance on the cation size. The ionic conductivity of electrolytes with relatively large cations, K(+), Rb(+) and Cs(+), was higher and essentially constant, while for the electrolytes containing the two smaller cations, Na(+) and Li(+), the conductivity values were lower. The temperature dependence of conductivity in this series appears to follow the Vogel-Tamman-Fulcher equation. The sample containing the smallest cation shows the lowest conductivity and the highest activation energy of ∼36.5 meV, while K(+), Rb(+) and Cs(+) containing samples show an activation energy of ∼30.5 meV. DSSCs based on the gel electrolyte and a TiO2 double layer with the N719 dye exhibited an enhancement in the open circuit voltage with increasing cation size. This can be attributed to the decrease in the recombination rate of electrons and to the conduction band shift resulting from cation adsorption by TiO2. The maximum efficiency value, 3.48%, was obtained for the CsI containing cell. The efficiencies shown in this study are lower compared to values reported in the literature, and this can be attributed to the use of a single salt and the absence of other additives, since the focus of the present study was to analyze the cation effect. The highest short circuit current density of 9.43 mA cm(-2) was shown by the RbI containing cell. The enhancement of the solar cell performance with increasing size of the cation is discussed in terms of the effect of the cations on the TiO2 anode and ion transport in the electrolyte. In liquid electrolyte based DSSCs, the short circuit current density

  16. Effects of oral powder electrolyte administration on packed cell volume, plasma chemistry parameters, and incidence of colic in horses participating in a 6-day 162-km trail ride.

    Science.gov (United States)

    Walker, Wade T; Callan, Robert J; Hill, Ashley E; Tisher, Kelly B

    2014-08-01

    This study evaluated the effects of administering oral powder electrolytes on packed cell volume (PCV), plasma chemistry parameters, and incidence of colic in horses participating on a 6-day 162-km trail ride in which water was not offered ad libitum. Twenty-three horses received grain with powder electrolytes daily while 19 control horses received grain only. Horses were ridden approximately 32 km a day at a walk or trot. Packed cell volume and plasma chemistry parameters were analyzed daily. Episodes of colic were diagnosed and treated by a veterinarian unaware of treatment group allocation. Blood parameters and incidence of colic were compared between treatment groups. Electrolyte administration did not alter PCV or plasma chemistry parameters compared to controls. The incidence of colic was significantly higher in treated horses (P = 0.05). Oral powder electrolytes did not enhance hydration status or electrolyte homeostasis and may be associated with colic in horses participating on long distance trail rides similar to this model. PMID:25082992

  17. 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.

  18. Cell pairing ratio controlled micro-environment with valve-less electrolytic isolation

    KAUST Repository

    Chen, Yu-Chih

    2012-01-01

    We present a ratio controlled cell-to-cell interaction chip using valve-less isolation. We incorporated electrolysis in a microfluidic channel. In each microfluidic chamber, we loaded two types of different cells at various pairing ratios. More than 80% of the microchambers were successfully loaded with a specific target pairing ratio. For the proof of concept, we have demonstrated the cell-to-cell interaction between prostate cancer cells and muscle stem cells can be controlled by cell pairing ratios through growth factor secretion. The experimental data shows that sealing of microenvironment by air generated from electrolysis does not affect cell viability and cell interaction assay results. © 2012 IEEE.

  19. Nanosized TiN-SBR hybrid coating of stainless steel as bipolar plates for polymer electrolyte membrane fuel cells

    International Nuclear Information System (INIS)

    In attempt to improve interfacial electrical conductivity of stainless steel for bipolar plates of polymer electrolyte membrane fuel cells, TiN nanoparticles were electrophoretically deposited on the surface of stainless steel with elastic styrene butadiene rubber (SBR) particles. From transmission electron microscopic observation, it was found that the TiN nanoparticles (ca. 50 nm) surrounded the spherical SBR particles (ca. 300-600 nm), forming agglomerates. They were well adhered on the surface of the type 310S stainless steel. With help of elasticity of SBR, the agglomerates were well fitted into the interfacial gap between gas diffusion layer (GDL) and stainless steel bipolar plate, and the interfacial contact resistance (ICR), simultaneously, was successfully reduced. A single cell using the TiN nanoparticles-coated bipolar plates, consequently, showed comparable cell performance with the graphite employing cell at a current density of 0.5 A cm-2 (12.5 A). Inexpensive TiN nanoparticle-coated type 310S stainless steel bipolar plates would become a possible alternate for the expensive graphite bipolar plates as use in fuel cell applications

  20. Analisa Efisiensi Kipas dan Simulasi Kecepatan Hidrogen di Dalam Micro Channel Sel Bahan Bakar (Fuel Cell) Polymer Electrolyte Membrane Kapasitas 20W

    OpenAIRE

    Juwirianto

    2015-01-01

    Fossil fuels are resources that produce electricity, power cars, and another equipment. Because of massive usage by human in earth, by the time fossil fuels will completely run out. Before this fossil fuels run out, we shall look for another unlimited alternative fuels. One of those alternative fuels is hydrogen. This study concerned with the Polymer Electrolyte Membrane Fuel Cell. This study will become the first study so there shall be a continuous study of fuel cell. Fuel cell is one of a ...

  1. Polymer Electrolyte Membranes for Fuel Cells by Radiation Induced Grafting: State of the Art at Paul Scherrer Institut

    International Nuclear Information System (INIS)

    Radiation induced grafting is a well established method for the preparation of polymer electrolyte membranes for fuel cells. This method allows the use of a wide variety of base films and monomers which may be tailored to the desired end-use. Since the method can be performed with low-cost starting materials, it offers the promise of cost-competitive membranes for the polymer electrolyte fuel cell (PEFC). Paul Scherrer Institut has been committed to developing fuel cell membranes by radiation grafting since 1992. Styrene based membranes using poly (tetrafluoroethylene-co-hexafluoropropylene) (FEP) and poly (ethylene-alt-tetrafluoroethylene) (ETFE) films as base material have been prepared by radiation grafting followed by sulfonation. Grafting parameters such as irradiation dose, reaction medium, temperature and time have been investigated in detail. The resulting grafted films and membranes have been characterized ex-situ for their thermal behaviour, composition, microstructure, fuel cell relevant properties, and membranes have been characterized in-situ and tested in low temperature PEFC. In addition, the use of α-methylstyrene (AMS), a substituted styrene monomer with protected α-position, for the preparation of alternative membranes of higher chemical stability has been investigated. The parameters of grafting were identified to have significant effect on the degree of grafting and were subsequently optimized [2]. The preparation steps and crosslinking affected thermal properties of the films. Small angle neutron scattering experiments revealed that the overall domain structure made up of crystalline and amorphous regimes of pristine polymer film is preserved. FTIR /ATR measurements indicated that radiation grafted films were more highly crosslinked in their near surface regions. The fuel cell performance of FEP based membranes was comparable to commercially available Nafion112 membranes of similar thickness and durability of several thousand hours. ETFE

  2. Influence of organic nitrogenous compounds phenothiazine and diphenyl amine in poly(vinylidene fluoride) blended with poly(ethylene oxide) polymer electrolyte in dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Highlights: • Phenothiazine and diphenyl amine were incorporated in polymer blend electrolyte is cost-effective method. • For first time, phenothiazine and diphenyl amine in PVdF-PEO based polymer electrolyte. • The PVdF-PEO/KI/I2/phenothiazine shows enhanced conductivity of 3.5 × 10−4 S cm−1. • Phenothiazine doped polymer blend electrolyte shows high efficiency of 8.5%. • This is higher efficiency than present day DSSCs with poly(vinylidine fluoride) polymer electrolyte. -- Abstract: The present study reports on the comparison of the performance of organic nitrogenous compounds namely, phenothiazine (PT) and diphenyl amine (DPA) in poly(vinylidene fluoride) (PVdF)–poly(ethylene oxide) (PEO) blend polymer electrolyte containing potassium iodide and iodine and its application in cis-dithiocyanato-bis (2,2′bipyridyl 4,4′dicarboxylic acid) ruthenium (II) complex (N3 dye) sensitized nanocrystalline TiO2 solar cells. PT and DPA have simple structures and possess lone pair electrons from nitrogen atoms; these electrons coordinate with iodine in the redox couple (I−/I3−) and tend to increase the conductivity of PVdF-PEO blend polymer electrolyte. On comparison of the electrical performance of PT and DPA in DSSC, the PT doped polymer blend electrolyte was observed to have an enhanced conductivity of 3.5 × 10−4 S cm−1. The DSSC fabricated using the PT doped polymer blend electrolyte demonstrated open-circuit voltage (Voc), short-current (Jsc), fill factor (ff) and conversion efficiency (η) values of 850 mV, 13.2 mA cm−2, 0.53 and 8.5% respectively, under illumination of 70 mW cm−2. The above results reveal that the electron density of PT appears to contribute to relatively higher interaction with iodine in the redox couple when compared to that in the DPA doped PVdF-PEO/KI/I2 polymer blend electrolyte. The structural modifications in the doped polymer blend electrolytes were characterized by X-ray diffraction (XRD), scanning electron

  3. Hexanoyl Chitosan-based Gel Electrolyte for Lithium-ion Cell

    Institute of Scientific and Technical Information of China (English)

    Tan Winie; A.K. Arof

    2005-01-01

    @@ 1Introduction Chitosan is soluble in dilute acid solutions as a result of salt formation by the amino groups with various inorganic and organic acids[1,2]. Due to the reactivity of water and other protic solvents such as methanol and acetic acid with the electrode material in the lithiumbased electrochemicaldevices[3], the insolubility of chitosan in aprotic solvents is inadequate to meet the requirements to be used as the electrolyte materials. In order to improve its solubility in aprotic solvents,acyl modification of chitosan was carried out in the present study.Hexanoyl-chitosan (Fig. 1) that exhibited solubility in THF was prepared by reacting the chitosan with hexanoyl chloride in a mixture of pyridine and THF[4].

  4. Modelling and Evaluation of Heating Strategies for High Temperature Polymer Electrolyte Membrane Fuel Cell Stacks

    DEFF Research Database (Denmark)

    Andreasen, Søren Juhl; Kær, Søren Knudsen

    2008-01-01

    Experiments were conducted on two different cathode air cooled high temperature PEM (HTPEM) fuel cell stacks; a 30 cell 400W prototype stack using two bipolar plates per cell, and a 65 cell 1 kW commercial stack using one bipolar plate per cell. The work seeks to examine the use of different...

  5. Polymer membrane based electrolytic cell and process for the direct generation of hydrogen peroxide in liquid streams

    Science.gov (United States)

    White, James H. (Inventor); Schwartz, Michael (Inventor); Sammells, Anthony F. (Inventor)

    1997-01-01

    An electrolytic cell for generating hydrogen peroxide is provided including a cathode containing a catalyst for the reduction of oxygen, and an anode containing a catalyst for the oxidation of water. A polymer membrane, semipermeable to either protons or hydroxide ions is also included and has a first face interfacing to the cathode and a second face interfacing to the anode so that when a stream of water containing dissolved oxygen or oxygen bubbles is passed over the cathode and a stream of water is passed over the anode, and an electric current is passed between the anode and the cathode, hydrogen peroxide is generated at the cathode and oxygen is generated at the anode.

  6. Fabrication of polymer electrolyte membranes fuel cell as reduction of ETFE film polymer structure using electron beam

    International Nuclear Information System (INIS)

    Crosslinking of ETFE polymer electrolyte membranes (PEMs) by combining several sources such as, -Electron beam (EB) -Thermal energy Characteristics of ETFE membrane: Ion exchange capacity (IEC), Water-uptake(WU) Size increment(SI), Tensile test, Chemical resistance Ionic conductivity (IC) Electric characteristics in PEMFC. Grafting monomer: Styrene (S), Methylstyrene (MS), Ion exchange capacity: Titration method with 0.1N NaOH Water-uptake : 24hr in DI water, room temp. = 26 .deg. C Tensile test: In stron analyzer Chemical resistance: 28% H2O2, 50 .deg. C Size increment: % wt-change after Di water-swelled at 26 .deg. C and for 24hr Ionic conductivity: 4 probe, measured in DI water at 26 .deg. C Electric characteristics: PEMFC (H2/O2), Cell size : 1 Χ 1 cm2 Temp. range: 50∼70 .deg. C, Pt loading : 0.4mg/cm2

  7. Numerical study of droplet dynamics in a polymer electrolyte fuel cell gas channel using an embedded Eulerian-Lagrangian approach

    Science.gov (United States)

    Jarauta, Alex; Ryzhakov, Pavel; Secanell, Marc; Waghmare, Prashant R.; Pons-Prats, Jordi

    2016-08-01

    An embedded Eulerian-Lagrangian formulation for the simulation of droplet dynamics within a polymer electrolyte fuel cell (PEFC) channel is presented. Air is modeled using an Eulerian formulation, whereas water is described with a Lagrangian framework. Using this framework, the gas-liquid interface can be accurately identified. The surface tension force is computed using the curvature defined by the boundary of the Lagrangian mesh. The method naturally accounts for material property changes across the interface and accurately represents the pressure discontinuity. A sessile drop in a horizontal surface, a sessile drop in an inclined plane and droplets in a PEFC channel are solved for as numerical examples and compared to experimental data. Numerical results are in excellent agreement with experimental data. Numerical results are also compared to results obtained with the semi-analytical model previously developed by the authors in order to discuss the limitations of the semi-analytical approach.

  8. Impact of compression on gas transport in non-woven gas diffusion layers of high temperature polymer electrolyte fuel cells

    Science.gov (United States)

    Froning, Dieter; Yu, Junliang; Gaiselmann, Gerd; Reimer, Uwe; Manke, Ingo; Schmidt, Volker; Lehnert, Werner

    2016-06-01

    Gas transport in non-woven gas diffusion layers of a high-temperature polymer electrolyte fuel cell was calculated with the Lattice Boltzmann method. The underlying micro structure was taken from two sources. A real micro structure was analyzed in the synchrotron under the impact of a compression mask mimicking the channel/rib structure of a flow field. Furthermore a stochastic geometry model based on synchrotron X-ray tomography studies was applied. The effect of compression is included in the stochastic model. Gas transport in these micro structures was simulated and the impact of compression was analyzed. Fiber bundles overlaying the micro structure were identified which affect the homogeneity of the gas flow. There are significant deviations between the impact of compression on effective material properties for this type of gas diffusion layers and the Kozeny-Carman equation.

  9. Improvements of electrical properties containing carbon nanotube in epoxy/graphite bipolar plate for polymer electrolyte membrane fuel cells.

    Science.gov (United States)

    Lee, HongKi; Rim, HyungRyul; Lee, JaeYoung; Lee, Jongmin; Yoon, JeongMo; Bae, WooJung; Yang, SeungWeon

    2008-10-01

    The epoxy based graphite bipolar plate containing carbon nanotube (CNT) for polymer electrolyte membrane fuel cells (PEMFC) has been prepared and the electrical properties were compared. The density of graphite composite bipolar plate showed from 1.85 to 0.94 as expanded graphite content is increased from 10 to 50 w/o. The improvement of electrical properties was accomplished by addition of CNT. Rapid increase of conductivity was found due to the compensation between increases of the electrical pathway by addition of CNT and sufficient electrical contact among isolated large graphite particle. The polarisation curves of bipolar plate were measured at 1 M H2SO4 solution with 1 mV/sec of scan rate and the value of 1.903 uA/cm2 of corrosion rate was obtained. PMID:19198477

  10. Numerical Simulation of a Polymer electrolyte Fuel Cell; Simulacion Numerica de una Pila de combustible de Membrana Polimerica

    Energy Technology Data Exchange (ETDEWEB)

    San Fabian, D.; Naud, B.

    2005-07-01

    This document reproduces the final project of David San Fabian Ayuso, presented on May 26, 2005, for the obtention of the engineer degree of the Carlos III University of Madrid. A single-phase, isothermal model, including both electron and proton transport, is introduced for the simulation of polymer electrolyte fuel cells (PEM). The model is implemented in the commercial code Fluent 6.0, through the use of UDFs (User Defined Functions). In order to validate the model, a single canal of a PEM monocell is simulated in three dimensions. The obtained result are qualitatively satisfactory. It is observed that it is not essential to solve the current collectors when a monocell is considered (and not a stack). in the present study, the number of nodes is the computational grid appears to be too low in the membrane zone in order to make a complete validation of the model. (Author) 20 refs.

  11. Analysis of gas transport in polymer electrolyte fuel cells using porous structure constructed from X-ray nano CT

    Science.gov (United States)

    Kinefuchi, Ikuya; Oyama, Junpei; Yokoyama, Koji; Kubo, Norio; Tokumasu, Takashi; Matsumoto, Yoichiro

    2013-03-01

    This paper describes the analysis of gas transport in micro porous layers of polymer electrolyte fuel cells based on the three-dimensional structure obtained from X-ray nano computed tomography (CT). The polygonal surface representation of the porous structure was constructed from the cross-sectional CT images using the marching tetrahedrons algorithm. The diffusion flux through the porous layer was evaluated by the direct simulation Monte Carlo method since the characteristic pore size is comparable to the mean free path of gas molecules. The numerical simulation well reproduces the experimentally observed pressure dependence of diffusion resistance originating from the transition between Knudsen and molecular diffusion regimes. The effect of porous media morphology on gas transport was examined by an analysis of the trajectories of transmitted molecules through the porous layer. This work was partially supported by New Energy and Industrial Technology Development Organization (NEDO) of Japan.

  12. Electrochemical properties of TiNCrN-coated bipolar plates in polymer electrolyte membrane fuel cell environment

    International Nuclear Information System (INIS)

    The overall performance of multilayered TiN/CrN coatings suggests that they may show improved corrosion resistance compared to a single layer. Three TiN/CrN coatings deposited on 316L stainless steel substrates by radio frequency magnetron sputtering were evaluated under potentiodynamic, potentiostatic and electrochemical impedance spectroscopy tests. Electrochemical impedance spectroscopy was performed for 168 h in a corrosive environment at 70 oC to determine the coating performance at + 600 mVSCE under the simulated cathodic conditions in a polymer electrolyte membrane fuel cell. The results showed high protective efficiency and charge transfer resistance with decreasing inner layer thickness. X-ray diffraction confirmed the formation of a TiN/CrN(111) preferred orientation along with TiN/CrN (200) at thinner TiN layer.

  13. High-performance membrane-electrode assembly with an optimal polytetrafluoroethylene content for high-temperature polymer electrolyte membrane fuel cells

    DEFF Research Database (Denmark)

    Jeong, Gisu; Kim, MinJoong; Han, Junyoung;

    2016-01-01

    Although high-temperature polymer electrolyte membrane fuel cells (HT-PEMFCs) have a high carbon monoxide tolerance and allow for efficient water management, their practical applications are limited due to their lower performance than conventional low-temperature PEMFCs. Herein, we present a high...

  14. An investigation of the typical corrosion parameters used to test polymer electrolyte fuel cell bipolar plate coatings, with titanium nitride coated stainless steel as a case study

    Science.gov (United States)

    Orsi, A.; Kongstein, O. E.; Hamilton, P. J.; Oedegaard, A.; Svenum, I. H.; Cooke, K.

    2015-07-01

    Stainless steel bipolar plates (BPP) for polymer electrolyte membrane fuel cells (PEMFCs) have good manufacturability, durability and low costs, but inadequate corrosion resistance and elevated interfacial contact resistance (ICR) in the fuel cell environment. Thin film coatings of titanium nitride (TiN) of 1 μm in thickness, were deposited by means of physical vapour deposition (PVD) process on to stainless steel (SS) 316L substrates and were evaluated, in a series of tests, for their level of corrosion protection and ICR. In the ex-situ corrosion tests, variables such as applied potential, experimental duration and pH of the sulphate electrolyte at 80 °C were altered. The ICR values were found to increase after exposure to greater applied potentials and electrolytes of a higher pH. In terms of experimental duration, the ICR increased most rapidly at the beginning of each experiment. It was also found that the oxidation of TiN was accelerated after exposure to electrolytes of a higher pH. When coated BPPs were incorporated into an accelerated fuel cell test, the degradation of the fuel cell cathode resembled the plates that were tested at the highest anodic potential (1.4 VSHE).

  15. Y-doped BaZrO3 as a chemically stable electrolyte for proton-conducting solid oxide electrolysis cells (SOECs)

    KAUST Repository

    Bi, Lei

    2015-01-01

    A proton-conducting solid oxide electrolysis cell using an Y-doped BaZrO3 electrolyte film, which has been demonstrated to be chemically stable, was successfully fabricated for the first time and showed a promising electrolysis performance.

  16. In-situ study of the dendritic growth in lithium/polymer electrolyte-salt/lithium cells; Etude in-situ de la croissance dendritique dans des cellules lithium/POE-sel/lithium

    Energy Technology Data Exchange (ETDEWEB)

    Brissot, C.; Rosso, M.; Chazalviel, J.N. [Ecole Polytechnique, 91 - Palaiseau (France); Baudry, P.; Lascaud, S. [Electricite de France, 77 - Moret sur Loing (France). Direction des Etudes et Recherches

    1996-12-31

    The in-situ observation of dendritic growth in lithium/polymer electrolyte-LiTFSI/lithium battery cells shows that dendrites grow up with about the same rate as anion migration. Memory effects have been evidenced in cycling experiments and limit the dendrites length. An overall movement of the electrolyte due to variations of electrolyte concentration in the vicinity of the electrodes has been observed too. (J.S.) 13 refs.

  17. Enhancement of Oxygen Reduction and Mitigation of Ionomer Dry-Out Using Insoluble Heteropoly Acids in Intermediate Temperature Polymer-Electrolyte Membrane Fuel Cells

    OpenAIRE

    Alessandro Stassi; Irene Gatto; Ada Saccà; Vincenzo Baglio; Aricò, Antonino S.

    2015-01-01

    The use of Cs 0.5 H 0.5 PW 12 O 40 insoluble salt as a superacid promoter in the catalyst layer of a polymer electrolyte membrane fuel cell (PEMFC) has been investigated. An increase of performance has been recorded at intermediate temperatures (110–130 °C) and under low relative humidity (R.H.). The promoter appears to mitigate the ionomer dry-out effects in the catalytic layer and produces an increase of the extent of the catalyst-electrolyte interface as demonstrated by cyclic voltammet...

  18. Photovoltaic performance of bifacial dye sensitized solar cell using chemically healed binary ionic liquid electrolyte solidified with SiO2 nanoparticles

    International Nuclear Information System (INIS)

    Highlights: ► A bifacial DSSC is realized and irradiated from front and rear sides. ► Maximum efficiency was found for 70% PMII/30% (EMIB(CN)4) electrolyte composition. ► A significant increase in photocurrent using 0.1 M GuSCN and 0.4 M NMB was observed. ► Addition of SiO2 nanoparticles to the electrolyte enhanced photovoltaic efficiency. ► Dispersed SiO2 particles are found to be more efficient compared to SiO2 overlayer. - Abstract: In this study, we investigated the effect of electrolyte composition, photoanode thickness, and the additions of GuSCN (guanidinium thiocyanate), NMB (N-methylbenimidazole), and SiO2 on the photovoltaic performance of DSSCs (dye sensitized solar cells). A bifacial DSSC is realized and irradiated from front and rear sides. The devices give maximum photovoltaic efficiencies for 70% PMII (1-propyl-3-methyl-imidazolium iodide)/30% (EMIB(CN)4) (1-ethyl-3-methyl-imidazolium tetracyanoborate) electrolyte composition and 10 μm thick photoanode coating which is considered to be the ideal coating thickness for the diffusion length of electrolyte and dye absorption. A significant increase in the photocurrent for DSSCs with optimum molarity of 0.1 M GuSCN was observed due to decreased recombination which is believed to be surface passivation effect at photoanode electrolyte interface suppressing recombination rate. Moreover, optimum NMB molarity was found to be 0.4 for maximum efficiency. Addition of SiO2 to the electrolyte both as an overlayer and dispersed particles enhanced rear side illuminated cells where dispersed particles are found to be more efficient for the front side illuminated cells due to additional electron transport properties. Best rear side illuminated cell efficiency was 3.2% compared to front side illuminated cell efficiency of 4.2% which is a promising result for future rear side dye sensitized solar cell applications where front side illumination is not possible like tandem structures and for cells working from

  19. Plasma Membranes Modified by Plasma Treatment or Deposition as Solid Electrolytes for Potential Application in Solid Alkaline Fuel Cells

    Directory of Open Access Journals (Sweden)

    Christophe Coutanceau

    2012-07-01

    Full Text Available In the highly competitive market of fuel cells, solid alkaline fuel cells using liquid fuel (such as cheap, non-toxic and non-valorized glycerol and not requiring noble metal as catalyst seem quite promising. One of the main hurdles for emergence of such a technology is the development of a hydroxide-conducting membrane characterized by both high conductivity and low fuel permeability. Plasma treatments can enable to positively tune the main fuel cell membrane requirements. In this work, commercial ADP-Morgane® fluorinated polymer membranes and a new brand of cross-linked poly(aryl-ether polymer membranes, named AMELI-32®, both containing quaternary ammonium functionalities, have been modified by argon plasma treatment or triallylamine-based plasma deposit. Under the concomitant etching/cross-linking/oxidation effects inherent to the plasma modification, transport properties (ionic exchange capacity, water uptake, ionic conductivity and fuel retention of membranes have been improved. Consequently, using plasma modified ADP-Morgane® membrane as electrolyte in a solid alkaline fuel cell operating with glycerol as fuel has allowed increasing the maximum power density by a factor 3 when compared to the untreated membrane.

  20. Oxides with polyatomic anions considered as new electrolyte materials for solid oxide fuel cells (SOFCs)

    Energy Technology Data Exchange (ETDEWEB)

    Bin Hassan, Oskar Hasdinor

    2010-10-21

    Materials with Polyatomic anions of [Al{sub 2}O{sub 7}]{sup -8}, [Ti{sub 2}O{sub 8}]{sup -8} and [P{sub 2}O{sub 7}]{sup -4} were investigated with respect to their ionic conductivity properties as well as its thermal expansion properties with the aim to use them as SOFCs electrolytes. The polyatomic anion groups selected from the oxy-cuspidine family of Gd{sub 4}Al{sub 2}O{sub 9} and Gd{sub 4}Ti{sub 2}O{sub 10} as well as from pyrophosphate SnP{sub 2}O{sub 7}. The pure oxy-cuspidine Gd{sub 4}Al{sub 2}O{sub 9}, the series of Gd{sub 4}Al{sub 2-x}Mg{sub x}O{sub 9-x/2} with x=0.10-1.0 and Gd{sub 4-x}M{sub x}Al{sub 2}O{sub 9-x/2} (M=Ca, Sr) with x = 0.05-0.5 were prepared successfully by the citrate complexation method. All samples showed the crystal structure of monoclinic oxycuspidine structure with space group of P2{sub 1/c} and Z=4. No solid solution was observed for Gd{sub 4}Al{sub 2-x}Mg{sub x}O{sub 9-x/2} where additional phases of Gd{sub 2}O{sub 3} and MgO were presence. XRD semiquantitative analysis together with SEM-EDX analysis revealed that Mg{sup 2+} was not able to substitute the Al{sup 3+} ions even at low Mg{sup 2+} concentration. The solid solution limit of Gd{sub 4-x}Ca{sub x}Al{sub 2}O{sub 9-x/2} and Gd{sub 4-x}Sr{sub x}Al{sub 2}O{sub 9-x/2} was determined between 0.05-0.10 and 0.01-0.05 mol for Ca and Sr, respectively. Beyond the substitution limit Gd{sub 4}Al{sub 2}O{sub 9}, GdAlO{sub 3} and SrGd{sub 2}Al{sub 2}O{sub 7} appeared as additional phases. The highest electrical conductivity obtained at 900 C yielded {sigma}= 1.49 x 10{sup -4}Scm{sup -1} for Gd{sub 3.95}Ca{sub 0.05}Al{sub 2}O{sub 8.98}. In comparison, the conductivity of pure Gd{sub 4}Al{sub 2}O{sub 9} was {sigma}= 1.73 x 10{sup -5} Scm{sup -1}. The conductivities determined were in a similar range as those of other cuspidine materials investigated previously. The thermal expansion coefficient of Gd{sub 4}Al{sub 2}O{sub 9} at 1000 C was 7.4 x 10{sup -6}K{sup -1}. The earlier reported

  1. 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)

  2. The Seebeck coefficient and the Peltier effect in a polymer electrolyte membrane cell with two hydrogen electrodes

    International Nuclear Information System (INIS)

    Highlights: • The heat change associated with the hydrogen electrode in a polymer electrolyte cell is determined from Seebeck coefficient measurements. • When electric current is passed from left to right in the outer circuit, the anode becomes warmer, while the cathode becomes colder in a thermoelectric cell with hydrogen electrodes. • At Soret equilibrium for water in the fuel cell, most of the entropy of the fuel cell reaction is generated at the anode. -- Abstract: We report that the Seebeck coefficient of a Nafion membrane cell with hydrogen electrodes saturated with water vapour, at 1 bar hydrogen pressure and 340 K, is equal to 670 ± 50 μV/K, meaning that the entropy change of the anode reaction at reversible conditions (67 J/(K mol)) corresponds to a reversible heat release of 22 kJ/mol. The transported entropy of protons across the membrane at Soret equilibrium was estimated from this value to 1 ± 5 J/(K mol). The results were supported by the expected variation in the Seebeck coefficient with the hydrogen pressure. We report also the temperature difference of the electrodes, when passing electric current through the cell, and find that the anode is heated (a Peltier heat effect), giving qualitative support to the result for the Seebeck coefficient. The Seebeck and Peltier effects are related by non-equilibrium thermodynamics theory, and the Peltier heat of the cathode in the fuel cell is calculated for steady state conditions to 6 ± 2 kJ/mol at 340 K. The division of the reversible heat release between the anode and the cathode, can be expected to vary with the current density, as the magnitude of the current density can have a big impact on water transport and water concentration profile

  3. First application of diethyl oxalate as efficient additive in high performance dye-sensitized solar cells based on iodide/triiodide electrolyte

    International Nuclear Information System (INIS)

    In this study, diethyl oxalate (DEOX) is applied as an effective inexpensive additive based iodide/triiodide electrolyte in the dye-sensitized solar cells (DSSCs). Addition the suitable amount of DEOX as 1 M into the electrolyte shows dramatically improvement in the short circuit current (Jsc) and consequently, in the total conversion efficiency (η). The fabricated devices based on N719 and 2-cyano-3-(4-(diphenylamino) phenyl) acrylic acid (TPA) sensitizers with modified electrolyte show the efficiency of 7.33% and 2.63% at an irradiation of AM1.5, and an 37% and 22% energy conversion efficiency increments, respectively. The boost in the photocurrent density mainly is due to the molecular complex formation between DEOX and redox species in the electrolyte solution that promotes the electrochemical properties of electrolyte. Also, electrochemical impedance measurements indicate adsorbing of DEOX on the semiconductor surface leads to an incensement in the lifetime (τ) and the electron density (ns) in the conduction band (CB) of TiO2 that shifts the Fermi level (EF) which leads to small enhancement in the Voc. Adsorbing of DEOX on the titania surface retards the interfacial charge recombination that has a beneficial effect on the Voc and Jsc. Furthermore, we compares the effect mechanisms of DEOX and 4-tert-butylpyridine (TBP) additives on the cell performance by applying different electrolytes containing the additives. These results show that TBP increases Voc while DEOX additive has effect on the Jsc and using of combination of additives leads to a remarkable improvement in η. As a result, DEOX is a new promising co-additive which can be used for high efficient and low cost DSSCs

  4. Enhanced photovoltaic performance and long-term stability of dye-sensitized solar cells by incorporating SiO2 nanoparticles in binary ionic liquid electrolytes

    International Nuclear Information System (INIS)

    Hydrophilic SiO2 nanoparticles in a binary ionic liquid (bi-IL) consisting of 1-propyl-3-methylimidazolium iodide (PMII) and 1-ethyl-3-methyl-imidazolium dicyanimide (EMIDCA) facilitated electron transfer and solidified the electrolyte for a dye-sensitized solar cell (DSC). We investigated the dependence of charge transport and photovoltaic performance on the composition of bi-IL electrolytes with varied ratio of SiO2 nanoparticles. The electrochemical impedance spectra revealed a decreased resistance to charge transfer at the Pt counter electrode (Rct1) when SiO2 (up to 2.0 wt.%) was added, improving the photovoltaic parameters. The DSC based on a TiO2 nanocrystalline film (thickness 14.2 μm) with a composite ionic gel electrolyte of EMIDCA/PMII bi-IL (33 vol.% of EMIDCA) incorporating SiO2 (2 wt.%) exhibited a power conversion efficiency of 5.28% under simulated solar illumination (AM 1.5 G, 100 mW cm− 2). The durability of DSC with a SiO2 solidified electrolyte was superior to that of a liquid one, exhibiting good stability at 60 °C in darkness during an accelerated test for 1000 h. - Highlights: ► SiO2 nanoparticles were introduced in a binary ionic liquid electrolyte. ► Effect of various ratios of SiO2 nanoparticles in gel electrolytes was studied. ► Mechanism of charge transfer with addition of SiO2 nanoparticles was discussed. ► An enhanced solar to electric energy conversion efficiency of 5.28% was achieved. ► Thermal stability of a quasi-solid state dye-sensitized solar cell was improved

  5. Enhanced photovoltaic performance and long-term stability of dye-sensitized solar cells by incorporating SiO{sub 2} nanoparticles in binary ionic liquid electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hsin-Fang; Wu, Jhih-Lin; Hsu, Po-Ya [Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013, Taiwan, ROC (China); Tung, Yung-Liang [Energy and Environment Research Laboratories, Industrial Technology Research Institute, Hsinchu 30013, Taiwan, ROC (China); Ouyang, Fan-Yi [Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013, Taiwan, ROC (China); Kai, Ji-Jung, E-mail: jjkai@ess.nthu.edu.tw [Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013, Taiwan, ROC (China)

    2013-02-01

    Hydrophilic SiO{sub 2} nanoparticles in a binary ionic liquid (bi-IL) consisting of 1-propyl-3-methylimidazolium iodide (PMII) and 1-ethyl-3-methyl-imidazolium dicyanimide (EMIDCA) facilitated electron transfer and solidified the electrolyte for a dye-sensitized solar cell (DSC). We investigated the dependence of charge transport and photovoltaic performance on the composition of bi-IL electrolytes with varied ratio of SiO{sub 2} nanoparticles. The electrochemical impedance spectra revealed a decreased resistance to charge transfer at the Pt counter electrode (R{sub ct1}) when SiO{sub 2} (up to 2.0 wt.%) was added, improving the photovoltaic parameters. The DSC based on a TiO{sub 2} nanocrystalline film (thickness 14.2 μm) with a composite ionic gel electrolyte of EMIDCA/PMII bi-IL (33 vol.% of EMIDCA) incorporating SiO{sub 2} (2 wt.%) exhibited a power conversion efficiency of 5.28% under simulated solar illumination (AM 1.5 G, 100 mW cm{sup −} {sup 2}). The durability of DSC with a SiO{sub 2} solidified electrolyte was superior to that of a liquid one, exhibiting good stability at 60 °C in darkness during an accelerated test for 1000 h. - Highlights: ► SiO{sub 2} nanoparticles were introduced in a binary ionic liquid electrolyte. ► Effect of various ratios of SiO{sub 2} nanoparticles in gel electrolytes was studied. ► Mechanism of charge transfer with addition of SiO{sub 2} nanoparticles was discussed. ► An enhanced solar to electric energy conversion efficiency of 5.28% was achieved. ► Thermal stability of a quasi-solid state dye-sensitized solar cell was improved.

  6. Effects of crown ethers in nanocomposite silica-gel electrolytes on the performance of quasi-solid-state dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Kuan-Chieh; Vittal, R.; Ho, Kuo-Chuan

    2010-04-15

    The effects of crown ethers (CEs) on the performance of quasi-solid-state dye-sensitized solar cells (DSSCs) have been investigated. Nanocomposite silica was used to form gel matrices in the electrolytes, which contained lithium iodide (LiI) and iodine (I{sub 2}) in 3-methoxypropionitrile (MPN) solvent. Three types of CEs, 12-crown-4 (12-C-4), 15-crown-5 (15-C-5), and 18-crown-6 (18-C-6) were used as additives to the gel electrolytes. DSSCs containing CEs showed enhancements in solar-to-electricity conversion efficiencies ({eta}), with reference to the one without them. The crown ether, 15-C-5, with a size of cavity matching with the size of Li{sup +} in the electrolyte rendered for its DSSC the best performance with an {eta} of 3.60%, under 100 mW/cm{sup 2} illumination, as compared to 2.44% for the cell without any CE. Enhancements in the photovoltaic parameters of the cells with the CEs were explained based on the binding abilities of the CEs with lithium ions (Li{sup +}) in the electrolyte. Linear sweep voltammetry (LSV) measurements and electrochemical impedance spectra were used to substantiate the explanations. (author)

  7. Effects of crown ethers in nanocomposite silica-gel electrolytes on the performance of quasi-solid-state dye-sensitized solar cells

    KAUST Repository

    Huang, Kuan-Chieh

    2010-04-01

    The effects of crown ethers (CEs) on the performance of quasi-solid-state dye-sensitized solar cells (DSSCs) have been investigated. Nanocomposite silica was used to form gel matrices in the electrolytes, which contained lithium iodide (LiI) and iodine (I2) in 3-methoxypropionitrile (MPN) solvent. Three types of CEs, 12-crown-4 (12-C-4), 15-crown-5 (15-C-5), and 18-crown-6 (18-C-6) were used as additives to the gel electrolytes. DSSCs containing CEs showed enhancements in solar-to-electricity conversion efficiencies (η), with reference to the one without them. The crown ether, 15-C-5, with a size of cavity matching with the size of Li+ in the electrolyte rendered for its DSSC the best performance with an η of 3.60%, under 100 mW/cm2 illumination, as compared to 2.44% for the cell without any CE. Enhancements in the photovoltaic parameters of the cells with the CEs were explained based on the binding abilities of the CEs with lithium ions (Li+) in the electrolyte. Linear sweep voltammetry (LSV) measurements and electrochemical impedance spectra were used to substantiate the explanations. © 2009 Elsevier B.V. All rights reserved.

  8. Early embryonic development, assisted reproductive technologies, and pluripotent stem cell biology in domestic mammals

    DEFF Research Database (Denmark)

    Hall, Vanessa Jane; Hinrichs, K.; Lazzari, G.;

    2013-01-01

    Over many decades assisted reproductive technologies, including artificial insemination, embryo transfer, in vitro production (IVP) of embryos, cloning by somatic cell nuclear transfer (SCNT), and stem cell culture, have been developed with the aim of refining breeding strategies for improved...

  9. Investigation of sulfonated polysulfone membranes as electrolyte in a passive-mode direct methanol fuel cell mini-stack

    Energy Technology Data Exchange (ETDEWEB)

    Lufrano, F.; Baglio, V.; Staiti, P.; Stassi, A.; Arico, A.S.; Antonucci, V. [CNR - ITAE, Istituto di Tecnologie Avanzate per l' Energia ' ' Nicola Giordano' ' , Via Salita S. Lucia sopra Contesse n. 5 - 98126 S. Lucia - Messina (Italy)

    2010-12-01

    This paper reports on the development of polymer electrolyte membranes (PEMs) based on sulfonated polysulfone for application in a DMFC mini-stack operating at room temperature in passive mode. The sulfonated polysulfone (SPSf) with two degrees of sulfonation (57 and 66%) was synthesized by a well-known sulfonation process. SPSf membranes with different thicknesses were prepared and investigated. These membranes were characterized in terms of methanol/water uptake, proton conductivity, and fuel cell performance in a DMFC single cell and mini-stack operating at room temperature. The study addressed (a) control of the synthesis of sulfonated polysulfone, (b) optimization of the assembling procedure, (c) a short lifetime investigation and (d) a comparison of DMFC performance in active-mode operation vs. passive-mode operation. The best passive DMFC performance was 220 mW (average cell power density of about 19 mW cm{sup -2}), obtained with a thin SPSf membrane (70 {mu}m) at room temperature, whereas the performance of the same membrane-based DMFC in active mode was 38 mW cm{sup -2}. The conductivity of this membrane, SPSf (IEC = 1.34 mequiv. g{sup -1}) was 2.8 x 10{sup -2} S cm{sup -1}. A preliminary short-term test (200 min) showed good stability during chrono-amperometry measurements. (author)

  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. Industrial-grade rare-earth and perovskite oxide for high-performance electrolyte layer-free fuel cell

    Science.gov (United States)

    Xia, Chen; Wang, Baoyuan; Ma, Ying; Cai, Yixiao; Afzal, Muhammad; Liu, Yanyan; He, Yunjuan; Zhang, Wei; Dong, Wenjing; Li, Junjiao; Zhu, Bin

    2016-03-01

    In the present work, we report a composite of industrial-grade material LaCePr-oxide (LCP) and perovskite La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) for advanced electrolyte layer-free fuel cells (EFFCs). The microstructure, morphology, and electrical properties of the LCP, LSCF, and LCP-LSCF composite were investigated and characterized by XRD, SEM, EDS, TEM, and EIS. Various ratios of LCP to LSCF in the composite were modulated to achieve balanced ionic and electronic conductivities. Fuel cell with an optimum ratio of 60 wt% LCP to 40 wt% LSCF reached the highest open circuit voltage (OCV) at 1.01 V and a maximum power density of 745 mW cm-2 at 575 °C, also displaying a good performance stability. The high performance is attributed to the interfacial mechanisms and electrode catalytic effects. The findings from the present study promote industrial-grade rare-earth oxide as a promising new material for innovative low temperature solid oxide fuel cell (LTSOFC) technology.

  12. Insights into the effect of structure-directing agents on structural properties of mesoporous carbon for polymer electrolyte fuel cells

    Indian Academy of Sciences (India)

    A Arunchander; K G Nishanth; K K Tintula; S Gouse Peera; A K Sahu

    2015-04-01

    Synthesis of mesoporous carbon (MC) with well-defined morphologies and, wide range of surface area and pore size, is reported by organic–organic interaction between thermally decomposable surfactants (structure-directing agents) and the cost-effective carbon precursors, such as phloroglucinol and formaldehyde. Selected surfactants based on tri-block co-polymer, non-ionic and ionic, are used for synthesis of MCs with wide variation in their physical properties. The present method could be applied to large-scale production of porous carbon with desired surface area and pore morphology and would practically be relevant to many emerging technologies including electrochemical power sources such as super-capacitors and fuel cells. In the present study, we have successfully used MCs as gas-diffusion layers in fuel cell electrodes and established proper balance between air permeability and water management. The porous carbon contributes significantly to reduce mass transfer existing at high current density region resulting in improved performance of the polymer electrolyte fuel cells.

  13. Advanced control of liquid water region in diffusion media of polymer electrolyte fuel cells through a dimensionless number

    Science.gov (United States)

    Wang, Yun; Chen, Ken S.

    2016-05-01

    In the present work, a three-dimension (3-D) model of polymer electrolyte fuel cells (PEFCs) is employed to investigate the complex, non-isothermal, two-phase flow in the gas diffusion layer (GDL). Phase change in gas flow channels is explained, and a simplified approach accounting for phase change is incorporated into the fuel cell model. It is found that the liquid water contours in the GDL are similar along flow channels when the channels are subject to two-phase flow. Analysis is performed on a dimensionless parameter Da0 introduced in our previous paper [Y. Wang and K. S. Chen, Chemical Engineering Science 66 (2011) 3557-3567] and the parameter is further evaluated in a realistic fuel cell. We found that the GDL's liquid water (or liquid-free) region is determined by the Da0 number which lumps several parameters, including the thermal conductivity and operating temperature. By adjusting these factors, a liquid-free GDL zone can be created even though the channel stream is two-phase flow. Such a liquid-free zone is adjacent to the two-phase region, benefiting local water management, namely avoiding both severe flooding and dryness.

  14. 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.

  15. LiTDI and solvent mixture based electrolytes for lithium-ion cells

    International Nuclear Information System (INIS)

    Electrolyte optimization for both best performance and low use of materials is described in this paper. Electrochemical performance and material utility are reported to achieve the goal of optimal combinations of salt concentration and solvent ratios for several solvent mixtures. A lithium 4,5-dicyano-2-trifluoromethanoimidazolide (LiTDI) salt was used for its thermal stability, ease of handling (stable in the presence of air and moisture) and high ionic conductivity at low concentration in solvents. Solvent mixtures were chosen based on industrial practice and performance at low temperature. The conductivity dependence of salt concentration is reported. In all systems, low concentration onset and a broad range of high conductivity was observed. Lithium cation transference numbers were measured for highly conductive samples and used as the secondary parameter in the optimization procedure. Both high ionic conductivity and transference number values were recorded, even for samples with low salt content: 0.3 mol kg−1 LiTDI in 1EC:2EMC (σ = 4.18 mS cm−1, TLi+ = 0.544) and 0.4 mol kg−1 LiTDI in EC:DMC:EMC (σ = 4.69 mS cm−1, TLi+ = 0.455). Cycling with anodic material was also carried out, showing good capacity for retention of the mixtures chosen containing average salt concentrations. Hence, material savings in comparison to other commercially available lithium salts is possible

  16. An investigation into the use of additive manufacture for the production of metallic bipolar plates for polymer electrolyte fuel cell stacks

    OpenAIRE

    Dawson, Richard; Patel, Anant; Rennie, Allan; White, Simon

    2015-01-01

    The bipolar plate is of critical importance to the efficient and long lasting operation of a polymer electrolyte fuel cell (PEMFC) stack. With advances in membrane electrode assembly design, greater attention has been focused on the bipolar plate and the important role it plays. Although carbon composite plates are a likely candidate for the mass introduction of fuel cells, it is metallic plates made from thin strip materials which could deliver significant advantages in terms of part cost, e...

  17. Boundary model-based reference control of blower cooled high temperature polymer electrolyte membrane fuel cells

    DEFF Research Database (Denmark)

    Jensen, Hans-Christian Becker; Kær, Søren Knudsen

    2011-01-01

    Fuel cells have, by design, a limited effective life time, which depends on how they are operated. The general consent is that operation of the fuel cell at the extreme of the operational range, or operation of the fuel cell without sufficient reactants (a.k.a. starvation), will lower the effecti...

  18. Small-signal ac response of an electrolytic cell with recombining space charge

    International Nuclear Information System (INIS)

    A simple model to evaluate the impedance of a cell in the presence of the generation and recombination of charges is proposed. The analysis is performed by considering a typical asymmetric cell having one electrode perfectly blocking and the other electrode perfectly transparent. The dependence of the impedance of the cell, in the shape of a slab, on the recombination coefficient is investigated. We obtain approximated expressions for the impedance of the cell valid in the low and high frequency regions. The frequencies defining the regions where approximated expressions hold are deduced by means of the asymptotic expansions for the real and imaginary parts of the electrical impedance of the cell.

  19. Composite electrolytes of polyethylene glycol methyl ether and TiO2 for dye-sensitized solar cells-Effect of heat treatment

    International Nuclear Information System (INIS)

    Highlights: → The heat treatment (80 deg. C) on prepared PEGME-TiO2 composite was essential step to improve the morphological and electrochemical properties. → Raman spectra of PEGME-acid, PEGME-TiO2 and PEGME-TiO2/80 deg. C composite electrolytes. → PEGME-TiO2/80 deg. C shows drastically increased strong peak (I3- species) with a slight shifting at 113.1 cm-1. → Indicates the significant increase of I3- species in redox electrolytes upon heat treatment. - Abstract: For solid-state dye-sensitized solar cells (DSSCs), a composite electrolyte of polyethylene glycol methyl ether (PEGME) and titania (TiO2) nanoparticles was prepared and characterized by Fourier transform-infra red (FT-IR), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and Raman spectroscopy. The heat treatment on PEGME and TiO2 composite was found to be an essential step to improve morphology, amorphicity and ionic conductivity of PEGME-TiO2 composite electrolytes. It was attributed to the increased bond strength of OC-O-Ti between PEGME and TiO2 and increased surface roughness of composite materials, which may help to absorb a large amount of iodide couple and effective generation of I3- ions. A DSSC fabricated with heat treated PEGME-TiO2 composite electrolyte showed significantly enhanced overall conversion efficiency of 3.1%, which was 20% higher than that of the DSSC fabricated with bare PEGME-TiO2 composite electrolyte.

  20. A modified anode/electrolyte structure for a solid oxide electrochemical cell and a method for making said structure

    DEFF Research Database (Denmark)

    2013-01-01

    -stabilised zirconium oxide electrolyte and (c) a metallic and/or a ceramic electrocatalyst in the shape of interlayers incorporated in the interface between the anode and the electrolyte. This assembly is first sintered at a given temperature and then at a lower temperature in reducing gas mixtures. These heat...... steps (a) and (b), (d) applying a layer of the selected anode backbone onto the electrolyte with applied interlayers, (e) sintering the raw assembly and (f) infiltrating the electrocatalyst precursor into the sintered assembly and heat treating the assembly to incorporate additional electrocatalyst into...... treatments resulted in a distribution of the metallic and/or ceramic interlayers in the electrolyte/anode backbone junction taking place. The structure is prepared by (a) depositing a ceramic interlayer onto one side of the electrolyte, (b) optionally applying a metallic interlayer thereon, (c) repeating...