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Sample records for alkaline electrolyte fuel cells

  1. DEVELOPMENT AND SELECTION OF IONIC LIQUID ELECTROLYTES FOR HYDROXIDE CONDUCTING POLYBENZIMIDAZOLE MEMBRANES IN ALKALINE FUEL CELLS

    Energy Technology Data Exchange (ETDEWEB)

    Fox, E.

    2012-05-01

    Alkaline fuel cell (AFC) operation is currently limited to specialty applications such as low temperatures and pure HO due to the corrosive nature of the electrolyte and formation of carbonates. AFCs are the cheapest and potentially most efficient (approaching 70%) fuel cells. The fact that non-Pt catalysts can be used, makes them an ideal low cost alternative for power production. The anode and cathode are separated by and solid electrolyte or alkaline porous media saturated with KOH. However, CO from the atmosphere or fuel feed severely poisons the electrolyte by forming insoluble carbonates. The corrosivity of KOH (electrolyte) limits operating temperatures to no more than 80°C. This chapter examines the development of ionic liquids electrolytes that are less corrosive, have higher operating temperatures, do not chemically bond to CO and enable alternative fuels. Work is detailed on the IL selection and characterization as well as casting methods within the polybenzimidazole based solid membrane. This approach is novel as it targets the root of the problem (the electrolyte) unlike other current work in alkaline fuel cells which focus on making the fuel cell components more durable.

  2. Alkaline fuel cells applications

    Science.gov (United States)

    Kordesch, Karl; Hacker, Viktor; Gsellmann, Josef; Cifrain, Martin; Faleschini, Gottfried; Enzinger, Peter; Fankhauser, Robert; Ortner, Markus; Muhr, Michael; Aronson, Robert R.

    On the world-wide automobile market technical developments are increasingly determined by the dramatic restriction on emissions as well as the regimentation of fuel consumption by legislation. Therefore there is an increasing chance of a completely new technology breakthrough if it offers new opportunities, meeting the requirements of resource preservation and emission restrictions. Fuel cell technology offers the possibility to excel in today's motive power techniques in terms of environmental compatibility, consumer's profit, costs of maintenance and efficiency. The key question is economy. This will be decided by the costs of fuel cell systems if they are to be used as power generators for future electric vehicles. The alkaline hydrogen-air fuel cell system with circulating KOH electrolyte and low-cost catalysed carbon electrodes could be a promising alternative. Based on the experiences of Kordesch [K. Kordesch, Brennstoffbatterien, Springer, Wien, 1984, ISBN 3-387-81819-7; K. Kordesch, City car with H 2-air fuel cell and lead-battery, SAE Paper No. 719015, 6th IECEC, 1971], who operated a city car hybrid vehicle on public roads for 3 years in the early 1970s, improved air electrodes plus new variations of the bipolar stack assembly developed in Graz are investigated. Primary fuel choice will be a major issue until such time as cost-effective, on-board hydrogen storage is developed. Ammonia is an interesting option. The whole system, ammonia dissociator plus alkaline fuel cell (AFC), is characterised by a simple design and high efficiency.

  3. Alkaline direct alcohol fuel cells

    Science.gov (United States)

    Antolini, E.; Gonzalez, E. R.

    The faster kinetics of the alcohol oxidation and oxygen reduction reactions in alkaline direct alcohol fuel cells (ADAFCs), opening up the possibility of using less expensive metal catalysts, as silver, nickel and palladium, makes the alkaline direct alcohol fuel cell a potentially low cost technology compared to acid direct alcohol fuel cell technology, which employs platinum catalysts. A boost in the research regarding alkaline fuel cells, fuelled with hydrogen or alcohols, was due to the development of alkaline anion-exchange membranes, which allows the overcoming of the problem of the progressive carbonation of the alkaline electrolyte. This paper presents an overview of catalysts and membranes for ADAFCs, and of testing of ADAFCs, fuelled with methanol, ethanol and ethylene glycol, formed by these materials.

  4. 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.

  5. New cross-linked PVA based polymer electrolyte membranes for alkaline fuel cells

    NARCIS (Netherlands)

    Merle, Geraldine; Hosseiny, Seyed Schwan; Wessling, Matthias; Nijmeijer, Dorothea C.

    2012-01-01

    In this paper, we report a cheap and easy method for the preparation of anion exchange membranes based on a KOH doped and crosslinked poly(vinyl alcohol) (PVA) for alkaline fuel cells. Ionic conductivity and thermal and chemical stability are investigated as a function of the crosslinking density.

  6. Plasma membranes modified by plasma treatment or deposition as solid electrolytes for potential application in solid alkaline fuel cells.

    Science.gov (United States)

    Reinholdt, Marc; Ilie, Alina; Roualdès, Stéphanie; Frugier, Jérémy; Schieda, Mauricio; Coutanceau, Christophe; Martemianov, Serguei; Flaud, Valérie; Beche, Eric; Durand, Jean

    2012-07-30

    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.

  7. Plasma Membranes Modified by Plasma Treatment or Deposition as Solid Electrolytes for Potential Application in Solid Alkaline Fuel Cells

    Science.gov (United States)

    Reinholdt, Marc; Ilie, Alina; Roualdès, Stéphanie; Frugier, Jérémy; Schieda, Mauricio; Coutanceau, Christophe; Martemianov, Serguei; Flaud, Valérie; Beche, Eric; Durand, Jean

    2012-01-01

    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. PMID:24958295

  8. Highly Zeolite-Loaded Polyvinyl Alcohol Composite Membranes for Alkaline Fuel-Cell Electrolytes

    Directory of Open Access Journals (Sweden)

    Po-Ya Hsu

    2018-01-01

    Full Text Available Having a secure and stable energy supply is a top priority for the global community. Fuel-cell technology is recognized as a promising electrical energy generation system for the twenty-first century. Polyvinyl alcohol/zeolitic imidazolate framework-8 (PVA/ZIF-8 composite membranes were successfully prepared in this work from direct ZIF-8 suspension solution (0–45.4 wt % and PVA mixing to prevent filler aggregation for direct methanol alkaline fuel cells (DMAFCs. The ZIF-8 fillers were chosen for the appropriate cavity size as a screening aid to allow water and suppress methanol transport. Increased ionic conductivities and suppressed methanol permeabilities were achieved for the PVA/40.5% ZIF-8 composites, compared to other samples. A high power density of 173.2 mW cm−2 was achieved using a KOH-doped PVA/40.5% ZIF-8 membrane in a DMAFC at 60 °C with 1–2 mg cm−2 catalyst loads. As the filler content was raised beyond 45.4 wt %, adverse effects resulted and the DMAFC performance (144.9 mW cm−2 was not improved further. Therefore, the optimal ZIF-8 content was approximately 40.5 wt % in the polymeric matrix. The specific power output was higher (58 mW mg−1 than most membranes reported in the literature (3–18 mW mg−1.

  9. 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 thermopl......A method for preparing polybenzimidazole or polybenzimidazole blend membranes and fabricating gas diffusion electrodes and membrane-electrode assemblies is provided for a high temperature polymer electrolyte membrane fuel cell. Blend polymer electrolyte membranes based on PBI and various...... thermoplastic polymers for high temperature polymer electrolyte fuel cells have also been developed. Miscible blends are used for solution casting of polymer membranes (solid electrolytes). High conductivity and enhanced mechanical strength were obtained for the blend polymer solid electrolytes...... electrolyte membrane by hot-press. The fuel cell can operate at temperatures up to at least 200 °C with hydrogen-rich fuel containing high ratios of carbon monoxide such as 3 vol% carbon monoxide or more, compared to the carbon monoxide tolerance of 10-20 ppm level for Nafion$m(3)-based polymer electrolyte...

  10. Development of alkaline fuel cells.

    Energy Technology Data Exchange (ETDEWEB)

    Hibbs, Michael R.; Jenkins, Janelle E.; Alam, Todd Michael; Janarthanan, Rajeswari; Horan, James L.; Caire, Benjamin R.; Ziegler, Zachary C.; Herring, Andrew M.; Yang, Yuan; Zuo, Xiaobing; Robson, Michael H.; Artyushkova, Kateryna; Patterson, Wendy; Atanassov, Plamen Borissov

    2013-09-01

    This project focuses on the development and demonstration of anion exchange membrane (AEM) fuel cells for portable power applications. Novel polymeric anion exchange membranes and ionomers with high chemical stabilities were prepared characterized by researchers at Sandia National Laboratories. Durable, non-precious metal catalysts were prepared by Dr. Plamen Atanassovs research group at the University of New Mexico by utilizing an aerosol-based process to prepare templated nano-structures. Dr. Andy Herrings group at the Colorado School of Mines combined all of these materials to fabricate and test membrane electrode assemblies for single cell testing in a methanol-fueled alkaline system. The highest power density achieved in this study was 54 mW/cm2 which was 90% of the project target and the highest reported power density for a direct methanol alkaline fuel cell.

  11. Application of Electrochemical Impedance Spectroscopy for Fuel Cell Characterization: Polymer Electrolyte Fuel Cell (PEFC) and Oxygen Reduction Reaction in Alkaline Solution

    OpenAIRE

    Wagner, Norbert

    2012-01-01

    Separation of different electrochemical and ohmic contributions to the current/voltage U(i) characteristics requires additional experimental techniques like Electrochemical Impedance Spectroscopy (EIS). The application of EIS is an approach to determine parameters which have proved to be indispensable for the characterization and development of fuel cell electrodes and electrolyte electrode assemblies. By varying the operating conditions of the fuel cell and by simulation of the measured ...

  12. Use of solid polymer electrolyte in alkaline fuel cells; Utilisation d'electrolyte solide polymere dans les piles a combustibles alcalines

    Energy Technology Data Exchange (ETDEWEB)

    Agel, E.; Bouet, J.; Fauvarque, J.F. [Conservatoire National des Arts et Metiers, CNAM, Lab. d' Electrochimie Industrielle, 75 - Paris (France); Yassir, H. [Lab. de Physico-Chimie et de Mise en Oeuvre de Materiaux Macromoleculaires, 75 - Paris (France)

    2000-07-01

    The aim of this work is to develop a new cheap type of anion exchange membranes to be applied as basic fuel cell. The anionic membrane, of polyelectrolyte type is prepared by the grafting of the quaternary amines (DABCO: diazabicycloctane, TEA: triethylamine) on an epichlorhydrine polymer following by a reticulation step. The ionic conductivities are above 10{sup -2} S.cm{sup -1}, with a rate of positive ionic sites of about the milli-equivalent per gram of material. The measured anionic transport numbers are superior to 0.90. The membranes which can absorb 30 to 50% of water are quasi-impermeable to the H{sub 2} and O{sub 2} gases and can run in temperature until 120 degrees Celsius. Thus, alkaline fuel cells containing these two types of membranes have shown good performance data. A particular attention is given to the membrane-electrode interface. (O.M.)

  13. hydrogel membrane as electrolyte for direct borohydride fuel cells

    Indian Academy of Sciences (India)

    Administrator

    Abstract. 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 gold- plated stainless steel mesh as cathode in conjunction with aqueous alkaline solution of sodium boro- hydride as fuel and ...

  14. hydrogel membrane as electrolyte for direct borohydride fuel cells

    Indian Academy of Sciences (India)

    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 ...

  15. A binary electrolyte model of a cylindrical alkaline cell

    Science.gov (United States)

    Kriegsmann, J. J.; Cheh, H. Y.

    A cylindrical alkaline cell is modeled as a binary electrolyte system by assuming the direct electrochemical formation of ZnO in the anode. Justifications for replacing the dissolution-precipitation mechanism are provided. Compared to the original model, the binary electrolyte model has a more understandable model formulation, more consistent physical property data, and greater flexibility in certain instances. The binary electrolyte model predicts a longer cell life and higher operating voltage than the ternary electrolyte model for the test case discharge rate. There are no numerical difficulties associated with the zincate ion in the binary electrolyte model, because this species is not considered. The characteristics and advantages of the simplified anode behavior are discussed. An application of the binary electrolyte model is included.

  16. Electrolyte Additives for Phosphoric Acid Fuel Cells

    DEFF Research Database (Denmark)

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

    1993-01-01

    , 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.......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...

  17. Alkaline Exchange Membrane (AEM) for High-Efficiency Fuel Cells, Electrolyzers and Regenerative Fuel Cell Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Develop an alkaline exchange membrane (AEM)for use as a polymer electrolyte in both fuel cell and electrolyzer systems.  The ultimate goal in AEM development is...

  18. Mathematical modeling of polymer electrolyte fuel cells

    Science.gov (United States)

    Sousa, Ruy; Gonzalez, Ernesto R.

    Fuel cells with a polymer electrolyte membrane have been receiving more and more attention. Modeling plays an important role in the development of fuel cells. In this paper, the state-of-the-art regarding modeling of fuel cells with a polymer electrolyte membrane is reviewed. Modeling has allowed detailed studies concerning the development of these cells, e.g. in discussing the electrocatalysis of the reactions and the design of water-management schemes to cope with membrane dehydration. Two-dimensional models have been used to represent reality, but three-dimensional models can cope with some important additional aspects. Consideration of two-phase transport in the air cathode of a proton exchange membrane fuel cell seems to be very appropriate. Most fuel cells use hydrogen as a fuel. Besides safety concerns, there are problems associated with production, storage and distribution of this fuel. Methanol, as a liquid fuel, can be the solution to these problems and direct methanol fuel cells (DMFCs) are attractive for several applications. Mass transport is a factor that may limit the performance of the cell. Adsorption steps may be coupled to Tafel kinetics to describe methanol oxidation and methanol crossover must also be taken into account. Extending the two-phase approach to the DMFC modeling is a recent, important point.

  19. 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.

  20. based anion exchange membrane for alkaline polymer electrolyte

    Indian Academy of Sciences (India)

    Administrator

    Alkaline polymer electrolyte fuel cell; anion exchange membrane; PPO; homogeneous quaterni- zation. 1. Introduction. Presently, alkaline polymer electrolyte fuel cells (APEFCs) using anion exchange membranes have received an immense interest among researchers (Varcoe and Slade. 2005). The advantages of ...

  1. 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.

  2. Inorganic salt mixtures as electrolyte media in fuel cells

    Science.gov (United States)

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

    2012-01-01

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

  3. Solid polymer electrolyte fuel cells

    International Nuclear Information System (INIS)

    Giorgi, L.; Pozio, A.

    1995-05-01

    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

  4. High Temperature Polymer Electrolyte Fuel Cells

    DEFF Research Database (Denmark)

    Fleige, Michael

    This thesis presents the development and application of electrochemical half-cell setups to study the catalytic reactions taking place in High Temperature Polymer Electrolyte Fuel Cells (HTPEM-FCs): (i) a pressurized electrochemical cell with integrated magnetically coupled rotating disk electrode...... at potentials, which approach the usual cathode potentials of HTPEM-FCs. Therefore, it seems that H3PO4-based fuel cells are not much suited to efficiently convert ethanol in accordance with findings in earlier research papers. Given that HTPEM-FCs can tolerate CO containing reformate gas, focusing research...... activities on catalysts for reformate oxidation appears more rational. Improvements of the ORR activity at the cathode can have large influence on the performance of HTPEM-FCs. The measurements of oxygen diffusivity and solubility contribute to the understanding of oxygen mass transport at the interface...

  5. Principles and Materials Aspects of Direct Alkaline Alcohol Fuel Cells

    Directory of Open Access Journals (Sweden)

    Eileen Hao Yu

    2010-08-01

    Full Text Available Direct alkaline alcohol fuel cells (DAAFCs have attracted increasing interest over the past decade because of their favourable reaction kinetics in alkaline media, higher energy densities achievable and the easy handling of the liquid fuels. In this review, principles and mechanisms of DAAFCs in alcohol oxidation and oxygen reduction are discussed. Despite the high energy densities available during the oxidation of polycarbon alcohols they are difficult to oxidise. Apart from methanol, the complete oxidation of other polycarbon alcohols to CO2 has not been achieved with current catalysts. Different types of catalysts, from conventional precious metal catalyst of Pt and Pt alloys to other lower cost Pd, Au and Ag metal catalysts are compared. Non precious metal catalysts, and lanthanum, strontium oxides and perovskite-type oxides are also discussed. Membranes like the ones used as polymer electrolytes and developed for DAAFCs are reviewed. Unlike conventional proton exchange membrane fuel cells, anion exchange membranes are used in present DAAFCs. Fuel cell performance with DAAFCs using different alcohols, catalysts and membranes, as well as operating parameters are summarised. In order to improve the power output of the DAAFCs, further developments in catalysts, membrane materials and fuel cell systems are essential.

  6. Technological development and prospect of alkaline fuel cells

    International Nuclear Information System (INIS)

    Meng Ni; Michael KH Leung; Dennis YC Leung

    2006-01-01

    This paper reviewed the technological development of alkaline fuel cell (AFC). Although the technology was popular in 1970's and 1980's, there has been a decline in AFC research over the past decade, mainly due to the poisoning of CO 2 . Continuous efforts have demonstrated that CO 2 concentration could be reduced to an acceptable level by a number of viable methods such as absorption, adsorption, electrochemical process, electrolyte circulation, use of liquid hydrogen, and use of solid anionic exchange membranes. Literature survey showed that AFC lifetime could achieve up to 5000 hours. In addition, the use of ammonia as a fuel for AFC was identified as a promising technology. Comparison between AFC and proton exchange membrane fuel cell (PEMFC) was presented to evaluate the AFC technology and its economics. The present review and assessment showed the promise of AFC for the coming hydrogen economy and sustainable development. (authors)

  7. Cold Start of Polymer Electrolyte Fuel Cells

    Science.gov (United States)

    Tajiri, Kazuya; Wang, Chao-Yang

    The ability of polymer electrolyte fuel cells (PEFCs) to startup and operate under subzero temperatures has been an issue for the commercialization of the fuel cell vehicle (FCV). It is widely believed that during PEFC operation in a subzero temperature environment a portion of water produced from the oxygen reduction reaction (ORR) forms ice in the catalyst layer (CL) that hinders the oxygen transport to the reaction sites, until the PEFC eventually stops operation due to oxygen starvation. For the automotive application, successful cold start is defined as PEFC temperature increase above 0°C with self-heating before the cell shutdown due to oxygen starvation. Several automakers have already claimed capability of FCV startup from a subzero temperature environment. However, the underlying physics has only begun to emerge in the most recent literature.

  8. The development of a state-of-the-art experimental setup demonstrated by the investigation of fuel cell reactions in alkaline electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Wiberg, Gustav Karl Henrik

    2010-10-04

    The objectives of this work can be separated into three different topics: the design and development of a state-of-the art electrochemical experiment setup, which is then followed by two separate experimental studies in alkaline electrolyte. These studies demonstrate the capabilities of the experimental setup, and each focus on separate model catalysts. The first study investigated the influence of Pt oxide formation on the measured catalytic activity of FC relevant reactions on polycrystalline Pt in alkaline electrolyte. The second study focused on the characterisation of the ORR for a non-platinum catalyst, in this case Ag, by adapting the established thin-film RDE methodology employed for characterising Pt based electrocatalysts. A state-of-the-art electrochemical experimental setup comprises of a largely automated setup that allows meticulous control over experimental parameters such as potential, temperature, purging gas and solution convection. In order to realise such a setup, both experimental hardware and software were developed. In particular, a custom built analogue potentiostat optimised for single working electrode measurements was constructed. The potentiostat features R{sub sol}-compensation which can be monitored online due to its fully analogue design, allowing the precise current and potential relationship to be measured. In addition, the experimental throughput was enhanced by fabricating a modular add-on device, the MWE, which allows simultaneous electrochemical measurement on up to 8 parallel working electrodes. The MWE device is compatible with any single channel potentiostat, enhancing existing instrumentation. Several Teflon cells were designed for electrochemical investigations in acid and alkaline electrolytes, and were adapted to work using either the RDE or MWE. A gas changer was also assembled, which enabled computer controlled switching of electrolyte purge gas. Furthermore, in order to control the potentiostat and the accessory

  9. Quantification of carbon dioxide poisoning in air breathing alkaline fuel cells

    Science.gov (United States)

    Tewari, A.; Sambhy, V.; Urquidi Macdonald, M.; Sen, A.

    Carbon dioxide intolerance has impeded the development of alkaline fuel cells as an alternate source of power supply. The CO 2, in a fuel cell system, could come from the anode side (if "dirty" H 2 is used as fuel), from the cathode side (if air instead of pure O 2 is used as an oxidant) or from inside the electrolyte (if methanol is used as a fuel). In this work, an novel analytical approach is proposed to study and quantify the carbon dioxide poisoning problem. Accelerated tests were carried out in an alkaline fuel cell using methanol as a fuel with different electrical loads and varying the concentration of carbon dioxide in a mixture CO 2/O 2 used as oxidant. Two characteristic quantities, t max and R max, were specified which were shown to comprehensively define the nature and extent of carbon dioxide poisoning in alkaline fuel cells. The poisoning phenomenon was successfully quantified by determining the dependence of these characteristic quantities on the operating parameters, viz. atmospheric carbon dioxide concentration and applied electrical load. Such quantification enabled the prediction of the output of a fuel cell operating in a carbon dioxide enriched atmosphere. In addition, static and dynamic analyses of electrolytes were carried out to determine the dependence of cell current on the electrolyte composition in a fuel cell undergoing poisoning. It was observed that there is a critical concentration of KOH in the electrolyte only below which the effect of carbon dioxide poisoning is reflected on the cell performance. Potentiostatic polarization tests confirmed that the underlying reason for the decreased cell performance because of carbon dioxide poisoning is the sluggish kinetics of methanol oxidation in the presence of potassium carbonate in the electrolyte. Moreover, the decreased conductivity of the electrolyte resulting from hydroxide to carbonate conversion was also shown to increase the ohmic loses in an alkaline fuel cell leading to lower

  10. Low hydrostatic head electrolyte addition to fuel cell stacks

    Science.gov (United States)

    Kothmann, Richard E.

    1983-01-01

    A fuel cell and system for supply electrolyte, as well as fuel and an oxidant to a fuel cell stack having at least two fuel cells, each of the cells having a pair of spaced electrodes and a matrix sandwiched therebetween, fuel and oxidant paths associated with a bipolar plate separating each pair of adjacent fuel cells and an electrolyte fill path for adding electrolyte to the cells and wetting said matrices. Electrolyte is flowed through the fuel cell stack in a back and forth fashion in a path in each cell substantially parallel to one face of opposite faces of the bipolar plate exposed to one of the electrodes and the matrices to produce an overall head uniformly between cells due to frictional pressure drop in the path for each cell free of a large hydrostatic head to thereby avoid flooding of the electrodes. The bipolar plate is provided with channels forming paths for the flow of the fuel and oxidant on opposite faces thereof, and the fuel and the oxidant are flowed along a first side of the bipolar plate and a second side of the bipolar plate through channels formed into the opposite faces of the bipolar plate, the fuel flowing through channels formed into one of the opposite faces and the oxidant flowing through channels formed into the other of the opposite faces.

  11. Carbonate fuel cell endurance: Hardware corrosion and electrolyte management status

    Energy Technology Data Exchange (ETDEWEB)

    Yuh, C.; Johnsen, R.; Farooque, M.; Maru, H.

    1993-01-01

    Endurance tests of carbonate fuel cell stacks (up to 10,000 hours) have shown that hardware corrosion and electrolyte losses can be reasonably controlled by proper material selection and cell design. Corrosion of stainless steel current collector hardware, nickel clad bipolar plate and aluminized wet seal show rates within acceptable limits. Electrolyte loss rate to current collector surface has been minimized by reducing exposed current collector surface area. Electrolyte evaporation loss appears tolerable. Electrolyte redistribution has been restrained by proper design of manifold seals.

  12. Carbonate fuel cell endurance: Hardware corrosion and electrolyte management status

    Energy Technology Data Exchange (ETDEWEB)

    Yuh, C.; Johnsen, R.; Farooque, M.; Maru, H.

    1993-05-01

    Endurance tests of carbonate fuel cell stacks (up to 10,000 hours) have shown that hardware corrosion and electrolyte losses can be reasonably controlled by proper material selection and cell design. Corrosion of stainless steel current collector hardware, nickel clad bipolar plate and aluminized wet seal show rates within acceptable limits. Electrolyte loss rate to current collector surface has been minimized by reducing exposed current collector surface area. Electrolyte evaporation loss appears tolerable. Electrolyte redistribution has been restrained by proper design of manifold seals.

  13. Liquid-Feed Methanol Fuel Cell With Membrane Electrolyte

    Science.gov (United States)

    Surampudi, Subbarao; Narayanan, S. R.; Halpert, Gerald; Frank, Harvey; Vamos, Eugene

    1995-01-01

    Fuel cell generates electricity from direct liquid feed stream of methanol/water solution circulated in contact with anode, plus direct gaseous feed stream of air or oxygen in contact with cathode. Advantages include relative simplicity and elimination of corrosive electrolytic solutions. Offers potential for reductions in size, weight, and complexity, and for increases in safety of fuel-cell systems.

  14. Polymer electrolyte membrane fuel cell control with feed-forward ...

    African Journals Online (AJOL)

    Feed-forward and feedback control is developed in this work for Polymer electrolyte membrane (PEM) fuel cell stacks. The feed-forward control is achieved using different methods, including look-up table, fuzzy logic and neural network, to improve the fuel cell stack breathing control and prevent the problem of oxygen ...

  15. Fuel cell system with separating structure bonded to electrolyte

    Science.gov (United States)

    Bourgeois, Richard Scott; Gudlavalleti, Sauri; Quek, Shu Ching; Hasz, Wayne Charles; Powers, James Daniel

    2010-09-28

    A fuel cell assembly comprises a separating structure configured for separating a first reactant and a second reactant wherein the separating structure has an opening therein. The fuel cell assembly further comprises a fuel cell comprising a first electrode, a second electrode, and an electrolyte interposed between the first and second electrodes, and a passage configured to introduce the second reactant to the second electrode. The electrolyte is bonded to the separating structure with the first electrode being situated within the opening, and the second electrode being situated within the passage.

  16. Stress-life interrelationships associated with alkaline fuel cells

    Science.gov (United States)

    Thaller, Lawrence H.; Martin, Ronald E.; Stedman, James K.

    1987-01-01

    A review is presented concerning the interrelationships between applied stress and the expected service life of alkaline fuel cells. Only the physical, chemical, and electrochemical phenomena that take place within the fuel cell stack portion of an overall fuel cell system will be discussed. A brief review will be given covering the significant improvements in performance and life over the past two decades as well as summarizing the more recent advances in understanding which can be used to predict the performance and life characteristics of fuel cell systems that have yet to be built.

  17. 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)

  18. Chalcogen catalysts for polymer electrolyte fuel cell

    Science.gov (United States)

    Alonso-Vante, Nicolas [Buxerolles, FR; Zelenay, Piotr [Los Alamos, NM; Choi, Jong-Ho [Los Alamos, NM; Wieckowski, Andrzej [Champaign, IL; Cao, Dianxue [Urbana, IL

    2009-09-15

    A methanol-tolerant cathode catalyst and a membrane electrode assembly for fuel cells that includes such a cathode catalyst. The cathode catalyst includes a support having at least one transition metal in elemental form and a chalcogen disposed on the support. Methods of making the cathode catalyst and membrane electrode assembly are also described.

  19. Mass Spectrometry of Polymer Electrolyte Membrane Fuel Cells

    Directory of Open Access Journals (Sweden)

    Viktor Johánek

    2016-01-01

    Full Text Available The chemical analysis of processes inside fuel cells under operating conditions in either direct or inverted (electrolysis mode and their correlation with potentiostatic measurements is a crucial part of understanding fuel cell electrochemistry. We present a relatively simple yet powerful experimental setup for online monitoring of the fuel cell exhaust (of either cathode or anode side downstream by mass spectrometry. The influence of a variety of parameters (composition of the catalyst, fuel type or its concentration, cell temperature, level of humidification, mass flow rate, power load, cell potential, etc. on the fuel cell operation can be easily investigated separately or in a combined fashion. We demonstrate the application of this technique on a few examples of low-temperature (70°C herein polymer electrolyte membrane fuel cells (both alcohol- and hydrogen-fed subjected to a wide range of conditions.

  20. Mass Spectrometry of Polymer Electrolyte Membrane Fuel Cells.

    Science.gov (United States)

    Johánek, Viktor; Ostroverkh, Anna; Fiala, Roman; Rednyk, Andrii; Matolín, Vladimír

    2016-01-01

    The chemical analysis of processes inside fuel cells under operating conditions in either direct or inverted (electrolysis) mode and their correlation with potentiostatic measurements is a crucial part of understanding fuel cell electrochemistry. We present a relatively simple yet powerful experimental setup for online monitoring of the fuel cell exhaust (of either cathode or anode side) downstream by mass spectrometry. The influence of a variety of parameters (composition of the catalyst, fuel type or its concentration, cell temperature, level of humidification, mass flow rate, power load, cell potential, etc.) on the fuel cell operation can be easily investigated separately or in a combined fashion. We demonstrate the application of this technique on a few examples of low-temperature (70°C herein) polymer electrolyte membrane fuel cells (both alcohol- and hydrogen-fed) subjected to a wide range of conditions.

  1. Introducing catalyst in alkaline membrane for improved performance direct borohydride fuel cells

    Science.gov (United States)

    Qin, Haiying; Lin, Longxia; Chu, Wen; Jiang, Wei; He, Yan; Shi, Qiao; Deng, Yonghong; Ji, Zhenguo; Liu, Jiabin; Tao, Shanwen

    2018-01-01

    A catalytic material is introduced into the polymer matrix to prepare a novel polymeric alkaline electrolyte membrane (AEM) which simultaneously increases ionic conductivity, reduces the fuel cross-over. In this work, the hydroxide anion exchange membrane is mainly composed of poly(vinylalcohol) and alkaline exchange resin. CoCl2 is added into the poly(vinylalcohol) and alkaline exchange resin gel before casting the membrane to introduce catalytic materials. CoCl2 is converted into CoOOH after the reaction with KOH solution. The crystallinity of the polymer matrix decreases and the ionic conductivity of the composite membrane is notably improved by the introduction of Co-species. A direct borohydride fuel cell using the composite membrane exhibits an open circuit voltage of 1.11 V at 30 °C, which is notably higher than that of cells using other AEMs. The cell using the composite membrane achieves a maximum power density of 283 mW cm-2 at 60 °C while the cell using the membrane without Co-species only reaches 117 mW cm-2 at the same conditions. The outstanding performance of the cell using the composite membrane benefits from impregnation of the catalytic Co-species in the membrane, which not only increases the ionic conductivity but also reduces electrode polarization thus improves the fuel cell performance. This work provides a new approach to develop high-performance fuel cells through adding catalysts in the electrolyte membrane.

  2. 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)

  3. 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

  4. 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.

  5. Coated powder for electrolyte matrix for carbonate fuel cell

    International Nuclear Information System (INIS)

    Iacovangelo, C.D.; Browall, K.W.

    1985-01-01

    A plurality of electrolyte carbonate-coated ceramic particle which does not differ significantly in size from that of the ceramic particle and wherein no significant portion of the ceramic particle is exposed is fabricated into a porous tape comprised of said coated-ceramic particles bonded together by the coating for use in a molten carbonate fuel cell

  6. 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.

  7. Nanofiber Composite Membranes for Alkaline Fuel Cells: Generation of Compositional, Morphological, and Functional Property Relationships

    Science.gov (United States)

    2015-12-01

    properties of nanofiber composite anion-exchange membranes for alkaline fuel cells. A new membrane fabrication strategy, utilizing polymer fiber...Approved for Public Release; Distribution Unlimited Final Report: Nanofiber Composite Membranes for Alkaline Fuel Cells: Generation of Compositional...Park, NC 27709-2211 nanofibers, electrospinning, composite membranes, alkaline fuel cells REPORT DOCUMENTATION PAGE 11. SPONSOR/MONITOR’S REPORT NUMBER

  8. High performance direct methanol fuel cell with thin electrolyte membrane

    Science.gov (United States)

    Wan, Nianfang

    2017-06-01

    A high performance direct methanol fuel cell is achieved with thin electrolyte membrane. 320 mW cm-2 of peak power density and over 260 mW cm-2 at 0.4 V are obtained when working at 90 °C with normal pressure air supply. It is revealed that the increased anode half-cell performance with temperature contributes primarily to the enhanced performance at elevated temperature. From the comparison of iR-compensated cathode potential of methanol/air with that of H2/air fuel cell, the impact of methanol crossover on cathode performance decreases with current density and becomes negligible at high current density. Current density is found to influence fuel efficiency and methanol crossover significantly from the measurement of fuel efficiency at different current density. At high current density, high fuel efficiency can be achieved even at high temperature, indicating decreased methanol crossover.

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

    DEFF Research Database (Denmark)

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

    1995-01-01

    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...

  10. Fuel cell electrolytes: Evolution, properties and future prospects

    Science.gov (United States)

    Appleby, A. J.

    1994-04-01

    Any electrolyte with sufficient ionic conductivity may be used in a fuel cell, but to avoid concentration gradients in the electrolyte, active conduction should be via an ion produced in one electrode reaction and consumed in the other. This ion must be present at high concentration in the electrolyte. In aqueous fuel cells operating on hydrogen and oxygen, the only useful electrolytes have high concentrations of either H(+) or OH(-), i.e., strong acids or bases. The product of the anode reaction in aqueous acids, H(+), occurs as a 'carrier ion' complexed by H2O as H(H2O)(sub n)(+), where n lies between 1 and 4. The corresponding cathodic product ion in bases, OH(-), is itself a 'carrier ion', the reaction product of O(2-) from the reduction of O2 and H2O. Phosphoric acid is not an aqueous acid, but a unique self-ionizing amphoteric system, in effect a molten acidic H(+) salt. In molten salts, H(+) could be the primary conductor, e.g., in molten bisulfates. Less corrosive carbonate melts use a cathodic supply of CO2 supplied via the gas phase to give CO2(2-) as the O(2-) 'carrier ion'. A similar approach may be used in aqueous carbonates. No carrier material is needed in solid oxides, which conduct directly via O(2-) ion. The temperature windows for different electrolytes are limited by performance at the low end and materials considerations at the high end. As a result, there are no electrolytes capable of operation between 480 and 900 K, and between 1050 and 1220 K. Development of electrolytes for these temperature ranges would be valuable.

  11. 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)

  12. based anion exchange membrane for alkaline polymer electrolyte

    Indian Academy of Sciences (India)

    Administrator

    Abstract. Hydroxyl ion (OH–) conducting anion exchange membranes based on modified poly (phenylene oxide) are fabricated for their application in alkaline polymer electrolyte fuel cells (APEFCs). In the present study, chloromethylation of poly(phenylene oxide) (PPO) is performed by aryl substitution rather than benzyl.

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

    OpenAIRE

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

    2014-01-01

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

  14. Comparative Studies of Polymer Electrolyte Membrane Fuel Cell Stacks and Single Cells

    Science.gov (United States)

    2000-02-01

    in the Catalyst Layer and Effects of Both Perfluorosulfonate Ionomer and PTFE-Loaded Carbon on the Catalyst Layer of Polymer Electrolyte Fuel Cells ...financial support of this project. 12 References 1. T. F. Fuller, "Is a Fuel Cell in Your Future?" 77K Electrochemical Society Interface (Fall...ARMY RESEARCH LABORATORY mm^ n Comparative Studies of Polymer Electrolyte Membrane Fuel Cell Stacks and Single Cells Deryn Chu and Rongzhong

  15. Characterization of polymer electrolytes for fuel cell applications

    International Nuclear Information System (INIS)

    Zawodzinski, T.A. Jr.; Springer, T.E.; Uribe, F.; Gottesfeld, S.

    1992-01-01

    We review here our recent work on polymer electrolyte fuel cells emphasizing membrane transport issues. Transport parameters measured at 30 degrees C for several available perfluorosulfonic acid membranes are compared. The water sorption characteristics, diffusion coefficient of water, electroosmotic drag, and pretonic conductivity were determined for Nafion reg-sign 117, Membrane C, and Dow XUS 13204.10 Developmental Fuel Cell Membrane. The diffusion coefficient and conductivity of each of these membranes were determined as functions of membrane water content. Data on water sorption and conductivity are reported for an experimental membrane which is a modified form of Nafion. Contact angle measurements indicate that the surface of a perfluorosulfonic acid membrane exposed to water vapor is quite hydrophobic, even in the presence of saturated water vapor. Modeling of water distribution in PEFC's based on the uptake and transport data shows that membrane thickness contributes in a nonlinear fashion to performance in PEM fuel cells. Finally, some work currently underway is discussed

  16. Modeling Cold Start in a Polymer-Electrolyte Fuel Cell

    OpenAIRE

    Balliet, Ryan

    2010-01-01

    Polymer-electrolyte fuel cells (PEFCs) are electrochemical devices that create electricity by consuming hydrogen and oxygen, forming water and heat as byproducts. PEFCs have been proposed for use in applications that may require start-up in environments with temperatures below 0 degrees C. Doing so requires that the cell heat up, and when its own waste heat is used to do so, the process is referred to here as ``cold start.'' However, at low temperatures the cell's product water freezes, and i...

  17. 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.

  18. Low Crossover Polymer Electrolyte Membranes for Direct Methanol Fuel Cells

    Science.gov (United States)

    Prakash, G. K. Surya; Smart, Marshall; Atti, Anthony R.; Olah, George A.; Narayanan, S. R.; Valdez, T.; Surampudi, S.

    1996-01-01

    Direct Methanol Fuel Cells (DMFC's) using polymer electrolyte membranes are promising power sources for portable and vehicular applications. State of the art technology using Nafion(R) 117 membranes (Dupont) are limited by high methanol permeability and cost, resulting in reduced fuel cell efficiencies and impractical commercialization. Therefore, much research in the fuel cell field is focused on the preparation and testing of low crossover and cost efficient polymer electrolyte membranes. The University of Southern California in cooperation with the Jet Propulsion Laboratory is focused on development of such materials. Interpenetrating polymer networks are an effective method used to blend polymer systems without forming chemical links. They provide the ability to modify physical and chemical properties of polymers by optimizing blend compositions. We have developed a novel interpenetrating polymer network based on poly (vinyl - difluoride)/cross-linked polystyrenesulfonic acid polymer composites (PVDF PSSA). Sulfonation of polystyrene accounts for protonic conductivity while the non-polar, PVDF backbone provides structural integrity in addition to methanol rejection. Precursor materials were prepared and analyzed to characterize membrane crystallinity, stability and degree of interpenetration. USC JPL PVDF-PSSA membranes were also characterized to determine methanol permeability, protonic conductivity and sulfur distribution. Membranes were fabricated into membrane electrode assemblies (MEA) and tested for single cell performance. Tests include cell performance over a wide range of temperatures (20 C - 90 C) and cathode conditions (ambient Air/O2). Methanol crossover values are measured in situ using an in-line CO2 analyzer.

  19. Synthesis and characterisation of alkaline anionic-exchange membranes for direct alcohol fuel cells

    CSIR Research Space (South Africa)

    Nonjola, P

    2007-12-01

    Full Text Available , but the most important being proton exchange membrane fuel cell (PEMFC), which uses an acidic membrane like Nafion (sulfonated fluorocarbon polymers) as an electrolyte. The use of polymer electrolytes represents an interesting path to pursue...

  20. Development and characterization of direct ethanol fuel cells using alkaline anion-exchange membranes

    Science.gov (United States)

    Lim, Peck Cheng

    2009-08-01

    Alkaline membrane fuel cell (AMFC) is a relatively new fuel cell technology that is generating considerable interests. It offers the electrocatalytic advantages of conventional alkaline fuel cells, and the manufacturing and cost advantages of solid polymer electrolyte fuel cells. This project was carried out to develop and characterize high performance membrane electrode assemblies (MEAs) for all-solid-state AMFCs. The primary fuel of interests is ethanol, but hydrogen was used in the development stages to facilitate the diagnostic and evaluation of the fuel cell performance. In the preliminary investigation, AMFC was assembled using off-the-shelf electrodes and anion-exchange membrane (AEM). It was found that the performance of AMFC operating on ethanol fuel was limited by a large high-frequency resistance (HFR) value. The advantage of using non-toxic ethanol fuel was also compromised by the need to add hydrazine and potassium hydroxide to the fuel blend. Subsequently, a high performance MEA was developed for an all-solid-state AMFC, in which liquid electrolyte or other additives were not required during the operation of the fuel cell. Ionomer was incorporated in the formulation of catalyst ink, and the catalyst ink was directly coated on the anion-exchange membrane (AEM). An ionomer content of 20 wt.% was found to be the optimum amount required in the catalyst layers. It was demonstrated that the AMFC generated a maximum power density of 365 mW/cm2 and 213 mW/cm 2 with the use of hydrogen/oxygen and hydrogen/pure air, respectively. The performance of the AMFC was also found to be influenced by exposure to carbon dioxide in the air. Hence, the CCMs were pre-treated in potassium hydroxide solution and pure oxygen was used to condition the fuel cell to maximize the power output from the AMFCs. Although satisfactory performance was demonstrated in the AMFC, its stability during cell operation remains a major issue. The poor stability was attributed to degradation of

  1. Exploring single electrode reactions in polymer electrolyte fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Kuhn, H.; Wokaun, A.; Scherer, G.G. [Paul Scherrer Institute, Electrochemistry Laboratory, 5232 Villigen (Switzerland)

    2007-01-20

    Utilising a pseudo-reference electrode in polymer electrolyte fuel cells allows for the separation of anodic and cathodic contributions to the entire cell impedance. Modelling the impedance responses by using equivalent circuits inhibits the investigation of kinetic parameters of the basic electrochemical reactions, which take place at single electrode-electrolyte interfaces. Therefore, we evaluate single electrode impedance measurements by a kinetic model, which is based on specific reaction pathways, either for the oxygen reduction reaction (ORR) or the hydrogen oxidation reaction (HOR). As a consequence, it is possible to obtain kinetic parameters for the specific reaction of interest. Furthermore, the information gained from the single electrode impedance measurements and the kinetic model can give insight into single reactions steps. In particular, the ORR has to include a chemical step in the reaction pathway. (author)

  2. Imidazolium-Based Polymeric Materials as Alkaline Anion-Exchange Fuel Cell Membranes

    Science.gov (United States)

    Narayan, Sri R.; Yen, Shiao-Ping S.; Reddy, Prakash V.; Nair, Nanditha

    2012-01-01

    Polymer electrolyte membranes that conduct hydroxide ions have potential use in fuel cells. A variety of polystyrene-based quaternary ammonium hydroxides have been reported as anion exchange fuel cell membranes. However, the hydrolytic stability and conductivity of the commercially available membranes are not adequate to meet the requirements of fuel cell applications. When compared with commercially available membranes, polystyrene-imidazolium alkaline membrane electrolytes are more stable and more highly conducting. At the time of this reporting, this has been the first such usage for imidazolium-based polymeric materials for fuel cells. Imidazolium salts are known to be electrochemically stable over wide potential ranges. By controlling the relative ratio of imidazolium groups in polystyrene-imidazolium salts, their physiochemical properties could be modulated. Alkaline anion exchange membranes based on polystyrene-imidazolium hydroxide materials have been developed. The first step was to synthesize the poly(styrene-co-(1-((4-vinyl)methyl)-3- methylimidazolium) chloride through a free-radical polymerization. Casting of this material followed by in situ treatment of the membranes with sodium hydroxide solutions provided the corresponding hydroxide salts. Various ratios of the monomers 4-chloromoethylvinylbenzine (CMVB) and vinylbenzine (VB) provided various compositions of the polymer. The preferred material, due to the relative ease of casting the film, and its relatively low hygroscopic nature, was a 2:1 ratio of CMVB to VB. Testing confirmed that at room temperature, the new membranes outperformed commercially available membranes by a large margin. With fuel cells now in use at NASA and in transportation, and with defense potential, any improvement to fuel cell efficiency is a significant development.

  3. 2011 Alkaline Membrane Fuel Cell Workshop Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Pivovar, B.

    2012-02-01

    A workshop addressing the current state-of-the-art in alkaline membrane fuel cells (AMFCs) was held May 8-9, 2011, at the Crystal Gateway Marriott in Arlington, Virginia. This workshop was the second of its kind, with the first being held December 11-13, 2006, in Phoenix, Arizona. The 2011 workshop and associated workshop report were created to assess the current state of AMFC technology (taking into account recent advances), investigate the performance potential of AMFC systems across all possible power ranges and applications, and identify the key research needs for commercial competitiveness in a variety of areas.

  4. Development of anionic membranes produced by radiation-grafting for alkaline fuel cell applications

    International Nuclear Information System (INIS)

    Pereira, Clotilde Coppini

    2017-01-01

    Anion Exchange Membranes (AEMs) are a promising alternative to the development of more efficient electrolytes for alkaline fuel cells. In general, the AEMs are ionomeric membranes able to conduct hydroxide ions (OH - ) due to the quaternary ammonium groups, which confer high pH equivalent to the AEM. In order to develop alkaline membranes with high chemical and thermal stability, besides satisfactory ionic conductivity for alkaline fuel cells, membranes based on low density polyethylene (LDPE), ultrahigh weight molecular weight polyethylene (UHWHPE), poly(ethylene-co-tetrafluoroethylene) (PETFE) and poly(hexafluoropropylene-co-tetrafluoroethylene) (PFEP) previously irradiated by using 60 Co gamma and electron beam sources, have been synthesized by styrene-grafting, and functionalized with trimethylamine to introduced quaternary ammonium groups. The resulting membranes were characterized by electron paramagnetic resonance (EPR), Raman spectroscopy, thermogravimetry (TG) and electrochemical impedance spectroscopy (EIS). The determination of the grafting degree and water uptake were conducted by gravimetry and ion exchange capacity, by titration. The membranes synthesized with PELD and PEUHMW polymers pre-irradiated at 70 kGy and stored at low temperature (-70 deg C), up to 10 months, showed ionic conductivity results, in hydroxide form (OH - ), of 29 mS.cm -1 and 14 mS.cm -1 at 65 deg C, respectively. The PFEP polymers irradiated by the simultaneous process showed insufficient grating levels for the membrane synthesis, requiring more studies to improve the irradiation and grafting process. The styrene-grafted PETFE membranes, pre-irradiated at 70 kGy and stored at low temperature (-70 deg C), up to 10 months, showed ionic conductivity results, in hydroxide form (OH - ), of 90 mS.cm -1 to 165 mS.cm -1 , in the temperature range 30 to 60 deg C. Such results have demonstrated that LDPE, UHMWPE and PETFE based AEMs are promising electrolytes for alkaline fuel cell

  5. 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

  6. Hybrid proton-conducting membranes for polymer electrolyte fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Romero, Pedro [Institut de Ciencia de Materials de Barcelona (CSIC), Campus UAB, E-08193 Bellaterra (Barcelona) (Spain)]. E-mail: pedro.gomez@icmab.es; Asensio, Juan Antonio [Institut de Ciencia de Materials de Barcelona (CSIC), Campus UAB, E-08193 Bellaterra (Barcelona) (Spain); Institut Quimic de Sarria, Universitat Ramon Llull, Via Augusta 390, E-08017 Barcelona (Spain); Borros, Salvador [Institut Quimic de Sarria, Universitat Ramon Llull, Via Augusta 390, E-08017 Barcelona (Spain)

    2005-08-30

    The synthesis and characterization of a novel hybrid organic-inorganic material formed by phosphomolybdic acid H{sub 3}PMo{sub 12}O{sub 40} (PMo{sub 12}) and poly(2,5-benzimidazole) (ABPBI) is reported. This material, composed of two proton-conducting components, can be cast in the form of membranes from methanesulfonic acid (MSA) solutions. Upon impregnation with phosphoric acid, the hybrid membranes present higher conductivity than the best ABPBI polymer membranes impregnated in the same conditions. These electrolyte membranes are stable up to 200 deg. C, and have a proton conductivity of 3 x 10{sup -2} S cm{sup -1} at 185 deg. C without humidification. These properties make them very good candidates as membranes for polymer electrolyte membrane fuel cells (PEMFC) at temperatures of 100-200 deg. C.

  7. Seeking effective dyes for a mediated glucose-air alkaline battery/fuel cell

    Science.gov (United States)

    Eustis, Ross; Tsang, Tsz Ming; Yang, Brigham; Scott, Daniel; Liaw, Bor Yann

    2014-02-01

    A significant level of power generation from an abiotic, air breathing, mediated reducing sugar-air alkaline battery/fuel cell has been achieved in our laboratories at room temperature without complicated catalysis or membrane separation in the reaction chamber. Our prior studies suggested that mass transport limitation by the mediator is a limiting factor in power generation. New and effective mediators were sought here to improve charge transfer and power density. Forty-five redox dyes were studied to identify if any can facilitate mass transport in alkaline electrolyte solution; namely, by increasing the solubility and mobility of the dye, and the valence charge carried per molecule. Indigo dyes were studied more closely to understand the complexity involved in mass transport. The viability of water-miscible co-solvents was also explored to understand their effect on solubility and mass transport of the dyes. Using a 2.0 mL solution, 20% methanol by volume, with 100 mM indigo carmine, 1.0 M glucose and 2.5 M sodium hydroxide, the glucose-air alkaline battery/fuel cell attained 8 mA cm-2 at short-circuit and 800 μW cm-2 at the maximum power point. This work shall aid future optimization of mediated charge transfer mechanism in batteries or fuel cells.

  8. 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

  9. Characterization and optimization of polymer electrolyte fuel cell electrodes

    Science.gov (United States)

    Boyer, Christopher Carter

    Experimental characterization and modeling were combined to find a procedure for optimizing the design of polymer electrolyte membrane fuel cell (PEMFC) electrodes. The mass transfer and kinetic properties of the active layer used in electrodes fabricated at the Center for Electrochemical Systems and Hydrogen Research (CESHR) were characterized as a function of electrolyte polymer content NafionRTM, DuPont, Fayetteville, NC) and catalyst loading for different types of platinum catalysts (E-Tek, Natick, MA). Expressions from limiting cases of the fuel cell model showed the combination of electrode materials for maximum current density at maximum catalyst utilization. Models describing the fuel cell behavior were selected and used to explain how different operating pressures affect the system power density and efficiency. An "inert layer" method was developed to determine the effective proton conductivity of the active layer. A "buffer layer" method was developed to determine the oxygen diffusivity in the gas pores. A review of the literature and experiments at CESHR was used to determine the oxygen reduction activity of the active layer. Finally, a fitting method was developed to measure the agglomerate diffusivity from cell tests. A PEMFC model demonstrated that operating the fuel cell pressurized can improve the power density at high currents because of oxygen mass transport. limitations in the substrate. However. as better electrode designs improve oxygen mass transfer, pressurized operation will lose this advantage. In addition, the model confirmed that oxygen enrichment systems require too much energy to separate oxygen from air to improve the net performance of a fuel cell. From limiting approximations of the solutions of the differential material balances in the fuel cell model, a simple set of analytical expressions were derived that predict the optimum active layer thickness and maximum current density based on the materials of construction and operating

  10. 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.

  11. Membrane and MEA Development in Polymer Electrolyte Fuel Cells

    Science.gov (United States)

    Trogadas, Panagiotis; Ramani, Vijay

    The polymer electrolyte fuel cell (PEFC) is based on Nafion polymer membranes operating at a temperature of 80°C. The main characteristics (structure and properties) and problems of Nafion-based PEFC technology are discussed. The primary drawbacks of Nafion membranes are poor conductivity at low relative humidities (and consequently at temperatures >100°C and ambient pressure) and large crossover of methanol in direct methanol fuel cell (DMFC) applications. These drawbacks have prompted an extensive effort to improve the properties of Nafion and identify alternate materials to replace Nafion. Polymer electrolyte membranes (PEMs) are classified in modified Nafion, membranes based on functionalized non-fluorinated backbones and acid-base polymer systems. Perhaps the most widely employed approach is the addition of inorganic additives to Nafion membranes to yield organic/inorganic composite membranes. Four major types of inorganic additives that have been studied (zirconium phosphates, heteropolyacids, metal hydrogen sulfates, and metal oxides) are reviewed in the following. DMFC and H2/O2 (air) cells based on modified Nafion membranes have been successfully operated at temperatures up to 120°C under ambient pressure and up to 150°C under 3-5 atm. Membranes based on functionalized non-fluorinated backbones are potentially promising for high-temperature operation. High conductivities have been obtained at temperatures up to 180°C. The final category of polymeric PEMs comprises non-functionalized polymers with basic character doped with proton-conducting acids such as phosphoric acid. The advanced features include high CO tolerance and thermal management. The advances made in the fabrication of electrodes for PEM fuel cells from the PTFE-bound catalyst layers of almost 20 years ago to the present technology are briefly discussed. There are two widely employed electrode designs: (1) PTFE-bound, and (2) thin-film electrodes. Emerging methods include those featuring

  12. Zinc electrode in alkaline electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    McBreen, J.

    1995-12-31

    The zinc electrode in alkaline electrolyte is unusual in that supersaturated zincate solutions can form during discharge and spongy or mossy zinc deposits can form on charge at low overvoltages. The effect of additives on regular pasted ZnO electrodes and calcium zincate electrodes is discussed. The paper also reports on in situ x-ray absorption (XAS) results on mossy zinc deposits.

  13. Modeling and experimental diagnostics in polymer electrolyte fuel cells

    Science.gov (United States)

    Springer, T. E.; Wilson, M. S.; Gottesfeld, S.

    1993-12-01

    This paper presents a fit between model and experiments for well-humidified polymer electrolyte fuel cells operated to maximum current density with a range of cathode gas compositions. The model considers, in detail, losses caused by: (1) interfacial kinetics at the Pt/ionomer interface; (2) gas-transport and ionic-conductivity limitations in the catalyst layer; and (3) gas-transport limitations in the cathode backing. Our experimental data were collected with cells that utilized thin-film catalyst layers bonded directly to the membrane, and a separate catalyst-free hydrophobic backing layer. This structure allows a clearer resolution of the processes taking place in each of these distinguishable parts of the cathode. In our final comparison of model predictions with the experimental data, we stress the simultaneous fit of a family of complete polarization curves obtained for gas compositions ranging from 5 atoms O2 to a mixture of 5% O2 in N2, employing in each case the same model parameters for interracial kinetics, catalyst-layer transport, and backing-layer transport. This approach allowed us to evaluate losses in the cathode backing and in the cathode catalyst layer, and thus identify the improvements required to enhance the performance of air cathodes in polymer electrolyte fuel cells. Finally, we show that effects of graded depletion in oxygen along the gas flow channel can be accurately modeled using a uniform effective oxygen concentration in the flow channel, equal to the average of inlet and exit concentrations. This approach has enabled simplified and accurate consideration of oxygen utilization effects.

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

    Science.gov (United States)

    2014-01-01

    Graphitic carbon nitrides are investigated for developing highly durable Pt electrocatalyst supports for polymer electrolyte fuel cells (PEFCs). Three different graphitic carbon nitride materials were synthesized with the aim to address the effect of crystallinity, porosity, and composition on the catalyst support properties: polymeric carbon nitride (gCNM), poly(triazine) imide carbon nitride (PTI/Li+Cl–), and boron-doped graphitic carbon nitride (B-gCNM). Following accelerated corrosion testing, all graphitic carbon nitride materials are found to be more electrochemically stable compared to conventional carbon black (Vulcan XC-72R) with B-gCNM support showing the best stability. For the supported catalysts, Pt/PTI-Li+Cl– catalyst exhibits better durability with only 19% electrochemical surface area (ECSA) loss versus 36% for Pt/Vulcan after 2000 scans. Superior methanol oxidation activity is observed for all graphitic carbon nitride supported Pt catalysts on the basis of the catalyst ECSA. PMID:24748912

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

    Science.gov (United States)

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

    2014-04-03

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

  16. Advances in Ceramic Supports for Polymer Electrolyte Fuel Cells

    Directory of Open Access Journals (Sweden)

    Oran Lori

    2015-08-01

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

  17. Study of operating conditions and cell design on the performance of alkaline anion exchange membrane based direct methanol fuel cells

    Science.gov (United States)

    Prakash, G. K. Surya; Krause, Frederick C.; Viva, Federico A.; Narayanan, S. R.; Olah, George A.

    2011-10-01

    Direct methanol fuel cells using an alkaline anion exchange membrane (AAEM) were prepared, studied, and optimized. The effects of fuel composition and electrode materials were investigated. Membrane electrode assemblies fabricated with Tokuyama® AAEM and commercial noble metal catalysts achieved peak power densities between 25 and 168 mW cm-2 depending on the operating temperature, fuel composition, and electrode materials used. Good electrode wettability at the anode was found to be very important for achieving high power densities. The performance of the best AAEM cells was comparable to Nafion®-based cells under similar conditions. Factors limiting the performance of AAEM MEAs were found to be different from those of Nafion® MEAs. Improved electrode kinetics for methanol oxidation in alkaline electrolyte at Pt-Ru are apparent at low current densities. At high current densities, rapid CO2 production converts the hydroxide anions, necessary for methanol oxidation, to bicarbonate and carbonate: consequently, the membrane and interfacial conductivity are drastically reduced. These phenomena necessitate the use of aqueous potassium hydroxide and wettable electrode materials for efficient hydroxide supply to the anode. However, aqueous hydroxide is not needed at the cathode. Compared to AAEM-based fuel cells, methanol fuel cells based on proton-conducting Nafion® retain better performance at high current densities by providing the benefit of carbon dioxide rejection.

  18. Durability aspects of polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Sethuraman, Vijay Anand

    In order for the successful adoption of proton exchange membrane (PEM) fuel cell technology, it is imperative that durability is understood, quantified and improved. A number of mechanisms are known to contribute to PEMFC membrane electrode assembly (MEA) performance degradation. In this dissertation, we show, via experiments, some of the various processes that degrade the proton exchange membrane in a PEM fuel cell; and catalyst poisoning due to hydrogen sulfide (H2S) and siloxane. The effect of humidity on the chemical stability of two types of membranes, [i.e., perfluorosulfonic acid type (PFSA, NafionRTM 112) and biphenyl sulfone hydrocarbon type, (BPSH-35)] was studied by subjecting the MEAs to open-circuit voltage (OCV) decay and potential cycling tests at elevated temperatures and low inlet gas relative humidities. The BPSH-35 membranes showed poor chemical stability in ex situ Fenton tests compared to that of NafionRTM membranes. However, under fuel cell conditions, BPSH-35 MEAs outperformed NafionRTM 112 MEAs in both the OCV decay and potential cycling tests. For both membranes, (i) at a given temperature, membrane degradation was more pronounced at lower humidities and (ii) at a given relative humidity operation, increasing the cell temperature accelerated membrane degradation. Mechanical stability of these two types of membranes was also studied using relative humidity (RH) cycling. Hydrogen peroxide (H2O2) formation rates in a proton exchange membrane (PEM) fuel cell were estimated by studying the oxygen reduction reaction (ORR) on a rotating ring disc electrode (RRDE). Fuel cell conditions were replicated by depositing a film of Pt/Vulcan XC-72 catalyst onto the disk and by varying the temperature, dissolved O2 concentration and the acidity levels in HClO4. The HClO4 acidity was correlated to ionomer water activity and hence fuel cell humidity. H 2O2 formation rates showed a linear dependence on oxygen concentration and square dependence on water

  19. 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).

  20. Anionic-exchange membrane development for application in alcohol alkaline fuel cells

    CSIR Research Space (South Africa)

    Nonjola, S

    2010-09-01

    Full Text Available Ammonium quaternized polymers such as poly (arylene ether sulfones) are being developed and studied as candidates of ionomeric materials for application in alkaline fuel cells, due to their low cost and promising electrochemical properties...

  1. A high selectivity quaternized polysulfone membrane for alkaline direct methanol fuel cells

    CSIR Research Space (South Africa)

    Abuin, GC

    2015-04-01

    Full Text Available polysulfone membrane for alkaline direct methanol fuel cells Graciela C. Abuina, Esteban A. Franceschinib, Patrick Nonjolac, Mkhulu K. Mathec, Mmalewane Modibedic, Horacio R. Cortib,* aCentro de Procesos Superficiales, Instituto Nacional de Tecnología...

  2. Hot topics in alkaline exchange membrane fuel cells

    Science.gov (United States)

    Serov, Alexey; Zenyuk, Iryna V.; Arges, Christopher G.; Chatenet, Marian

    2018-01-01

    The tremendous progress from the first discovery of fuel cell principles by Sir William Robert Grove in 1839 [1] and independent observation of electricity generated in electrochemical reaction of hydrogen and air by a Swiss scientist Christian F. Shoenbein [2] to the recent breakthroughs in the fuel cell field resulted in the appearance of this clean energy technology around us. Indeed, fuel cell technology undoubtedly has entered into our life with the first introduction of Toyota Mirai Fuel Cell Vehicle (FCV) by Toyota Motor Co. in December of 2014 [3,4]. This FCV is commercially available and can be purchased in several countries. However, its sticker price of 57,500 substantially limits the number of customers that can purchase it. There are numerous factors that contribute to the high cost of fuel cell stack, however the price of platinum and platinum alloys is the main contributor [5].

  3. Device for equalizing molten electrolyte content in a fuel cell stack

    Science.gov (United States)

    Smith, J.L.

    1985-12-23

    A device for equalizing the molten electrolyte content throughout the height of a fuel cell stack is disclosed. The device includes a passageway for electrolyte return with electrolyte wettable wicking material in the opposite end portions of the passageway. One end portion is disposed near the upper, negative end of the stack where electrolyte flooding occurs. The second end portion is placed near the lower, positive end of the stack where electrolyte is depleted. Heating means are provided at the upper portion of the passageway to increase electrolyte vapor pressure in the upper wicking material. The vapor is condensed in the lower passageway portion and conducted as molten electrolyte in the lower wick to the positive end face of the stack. An inlet is provided to inject a modifying gas into the passageway and thereby control the rate of electrolyte return.

  4. Catalyst, Membrane, Free Electrolyte Challenges, and Pathways to Resolutions in High Temperature Polymer Electrolyte Membrane Fuel Cells

    Directory of Open Access Journals (Sweden)

    Timothy Myles

    2017-01-01

    Full Text Available High temperature polymer electrolyte membrane fuel cells (HT-PEMFCs are being studied due to a number of benefits offered versus their low temperature counterparts, including co-generation of heat and power, high tolerance to fuel impurities, and simpler system design. Approximately 90% of the literature on HT-PEM is related to the electrolyte and, for the most part, these electrolytes all use free phosphoric acid, or similar free acid, as the ion conductor. A major issue with using phosphoric acid based electrolytes is the free acid in the electrodes. The presence of the acid on the catalyst sites leads to poor oxygen activity, low solubility/diffusion, and can block electrochemical sites through phosphate adsorption. This review will focus on these issues and the steps that have been taken to alleviate these obstacles. The intention is this review may then serve as a tool for finding a solution path in the community.

  5. Experimental and analytical analysis of polarization and water transport behaviors of hydrogen alkaline membrane fuel cell

    Science.gov (United States)

    Huo, Sen; Zhou, Jiaxun; Wang, Tianyou; Chen, Rui; Jiao, Kui

    2018-04-01

    Experimental test and analytical modeling are conducted to investigate the operating behavior of an alkaline electrolyte membrane (AEM) fuel cell fed by H2/air (or O2) and explore the effect of various operating pressures on the water transfer mechanism. According to the experimental test, the cell performance is greatly improved through increasing the operating pressure gradient from anode to cathode which leads to significant liquid water permeation through the membrane. The high frequency resistance of the A901 alkaline membrane is observed to be relatively stable as the operating pressure varies based on the electrochemical impedance spectroscopy (EIS) method. Correspondingly, based on the modeling prediction, the averaged water content in the membrane electrode assembly (MEA) does not change too much which leads to the weak variation of membrane ohmic resistance. This reveals that the performance enhancement should give the credit to better electro-chemical reaction kinetics for both the anode and cathode, also prone by the EIS results. The reversion of water back diffusion direction across the membrane is also observed through analytical solution.

  6. Status of solid polymer electrolyte fuel cell technology and potential for transportation applications

    Science.gov (United States)

    McElroy, J. F.; Nuttall, L. J.

    The solid polymer electrolyte (SPE) fuel cell represents the first fuel cell technology known to be used operationally. Current activities are mainly related to the development of a space regenerative fuel cell system for energy storage on board space stations, or other large orbiting vehicles and platforms. During 1981, a study was performed to determine the feasibility of using SPE fuel cells for automotive or other vehicular applications, using methanol as the fuel. The results of this study were very encouraging. Details concerning a conceptual automotive fuel cell power plant study are discussed, taking into account also a layout of major components for compact passenger car installation.

  7. Modeling Cold Start in a Polymer-Electrolyte Fuel Cell

    Science.gov (United States)

    Balliet, Ryan James

    Polymer-electrolyte fuel cells (PEFCs) are electrochemical devices that create electricity by consuming hydrogen and oxygen, forming water and heat as byproducts. PEFCs have been proposed for use in applications that may require start-up in environments with temperatures below 0 degrees C. Doing so requires that the cell heat up, and when its own waste heat is used to do so, the process is referred to here as "cold start.'' However, at low temperatures the cell's product water freezes, and if the temperature does not rise fast enough, the accumulation of ice in the cathode catalyst layer (cCL) can reduce cell performance significantly, extending the time required to heat up. In addition to reducing performance during cold start, under some conditions the accumulation of ice can lead to irreversible structural degradation of the cCL. The objective of this dissertation is to construct and verify a cold-start model for a single PEFC, use it to improve understanding of cold-start behavior, and to demonstrate how this understanding can lead to better start protocols and material properties. The macrohomogeneous model that has been developed to meet the objective is two-dimensional, transient, and nonisothermal. A key differentiating feature is the inclusion of water in all four of the possible phases: ice, liquid, gas, and membrane. In order to predict water content in the ice, liquid, and gas phases that are present in the porous media, the thermodynamics of phase equilibrium are revisited, and a method for relating phase pressures to water content in each of these phases is developed. Verification of the model is performed by comparing model predictions for cell behavior during parametric studies to measured values taken from various sources. In most cases, good agreement is observed between the model and the experiments. Results from the simulations are used to explain the trends that are observed. The verified cold-start model is deployed to determine a cold

  8. Model-based analysis of water management in alkaline direct methanol fuel cells

    Science.gov (United States)

    Weinzierl, C.; Krewer, U.

    2014-12-01

    Mathematical modelling is used to analyse water management in Alkaline Direct Methanol Fuel Cells (ADMFCs) with an anion exchange membrane as electrolyte. Cathodic water supply is identified as one of the main challenges and investigated at different operation conditions. Two extreme case scenarios are modelled to study the feasible conditions for sufficient water supply. Scenario 1 reveals that water supply by cathodic inlet is insufficient and, thus, water transport through membrane is essential for ADMFC operation. The second scenario is used to analyse requirements on water transport through the membrane for different operation conditions. These requirements are influenced by current density, evaporation rate, methanol cross-over and electro-osmotic drag of water. Simulations indicate that water supply is mainly challenging for high current densities and demands on high water diffusion are intensified by water drag. Thus, current density might be limited by water transport through membrane. The presented results help to identify important effects and processes in ADMFCs with a polymer electrolyte membrane and to understand these processes. Furthermore, the requirements identified by modelling show the importance of considering water transport through membrane besides conductivity and methanol cross-over especially for designing new membrane materials.

  9. Transport phenomena in alkaline direct ethanol fuel cells for sustainable energy production

    Science.gov (United States)

    An, L.; Zhao, T. S.

    2017-02-01

    Alkaline direct ethanol fuel cells (DEFC), which convert the chemical energy stored in ethanol directly into electricity, are one of the most promising energy-conversion devices for portable, mobile and stationary power applications, primarily because this type of fuel cell runs on a carbon-neutral, sustainable fuel and the electrocatalytic and membrane materials that constitute the cell are relatively inexpensive. As a result, the alkaline DEFC technology has undergone a rapid progress over the last decade. This article provides a comprehensive review of transport phenomena of various species in this fuel cell system. The past investigations into how the design and structural parameters of membrane electrode assemblies and the operating parameters affect the fuel cell performance are discussed. In addition, future perspectives and challenges with regard to transport phenomena in this fuel cell system are also highlighted.

  10. Application of the Sensor Selection Approach in Polymer Electrolyte Membrane Fuel Cell Prognostics and Health Management

    Directory of Open Access Journals (Sweden)

    Lei Mao

    2017-09-01

    Full Text Available In this paper, the sensor selection approach is investigated with the aim of using fewer sensors to provide reliable fuel cell diagnostic and prognostic results. The sensitivity of sensors is firstly calculated with a developed fuel cell model. With sensor sensitivities to different fuel cell failure modes, the available sensors can be ranked. A sensor selection algorithm is used in the analysis, which considers both sensor sensitivity to fuel cell performance and resistance to noise. The performance of the selected sensors in polymer electrolyte membrane (PEM fuel cell prognostics is also evaluated with an adaptive neuro-fuzzy inference system (ANFIS, and results show that the fuel cell voltage can be predicted with good quality using the selected sensors. Furthermore, a fuel cell test is performed to investigate the effectiveness of selected sensors in fuel cell fault diagnosis. From the results, different fuel cell states can be distinguished with good quality using the selected sensors.

  11. Hydroxide Self-Feeding High-Temperature Alkaline Direct Formate Fuel Cells.

    Science.gov (United States)

    Li, Yinshi; Sun, Xianda; Feng, Ying

    2017-05-22

    Conventionally, both the thermal degradation of the anion-exchange membrane and the requirement of additional hydroxide for fuel oxidation reaction hinder the development of the high-temperature alkaline direct liquid fuel cells. The present work addresses these two issues by reporting a polybenzimidazole-membrane-based direct formate fuel cell (DFFC). Theoretically, the cell voltage of the high-temperature alkaline DFFC can be as high as 1.45 V at 90 °C. It has been demonstrated that a proof-of-concept alkaline DFFC without adding additional hydroxide yields a peak power density of 20.9 mW cm -2 , an order of magnitude higher than both alkaline direct ethanol fuel cells and alkaline direct methanol fuel cells, mainly because the hydrolysis of formate provides enough OH - ions for formate oxidation reaction. It was also found that this hydroxide self-feeding high-temperature alkaline DFFC shows a stable 100 min constant-current discharge at 90 °C, proving the conceptual feasibility. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Simulation of Mass Transfer Process for Polymer Electrolyte Membrane Fuel Cell Stack

    Science.gov (United States)

    2000-02-01

    Ionomer and PTFE-Loaded Carbon on the Catalyst Layer of Polymer Electrolyte Fuel Cells ," /. Electrochem. Soc. 142 (1995), p 4143. 9. F...References 1. T. F. Fuller, "Is a Fuel Cell in Your Future?" The Electrochemical Society Interface (Fall 1997), p 26. 2. E. A. Ticianelli, C. R. Derouin...and S. Srinivasan, "Localization of Plati- num in Low Catalyst Loading Electrodes to Attain High Power Density in SPE Fuel Cells ," /.

  13. Carbon-supported co-pyridine as non-platinum cathode catalyst for alkaline membrane fuel cells

    International Nuclear Information System (INIS)

    Qiao, Jinli; Xu, Li; Liu, Yuyu; Xu, Pan; Shi, Jingjing; Liu, Shiyao; Tian, Binglun

    2013-01-01

    Development of high-performance cost-effective electrocatalyts that can replace Pt catalyst have been a central theme in polymer electrolyte membrane fuel cells (PEMFCs) including direct methanol fuel cells (DMFCs). Here we show that carbon-supported pyridine–cobalt nanoparticles (CoPy/C) can generate a high catalytic activity toward the oxygen reduction reaction (ORR). The catalysts are synthesized using cobalt sulfate heptahydrate (CoSO 4 ·7H 2 O) and pyridine (Py) as the Co and N precursors via a solid state reaction by heat-treatment in an inert atmosphere at 800 °C. In particular, the ORR kinetics on these catalyst materials are evaluated using rotating disk electrode (RDE) technique in electrolytes of various KOH concentrations, ranging from 0.05 to 12 M. The Koutecky–Levich equation analyses indicate that the transferred electron number, n, per oxygen molecule on CoPy/C electrode depend on the low negative ovevrpotentials in low KOH concentrations, whereas in high KOH concentrations the values of n for oxygen reduction depend on the high negative overpotentials, and varies between 3.5 and 4.0. These catalysts exhibit the superior methanol tolerance to commercial 40%Pt/C catalyst, and the negative effect of high KOH concentration is much less for CoPy/C than for Pt/C, suggesting the promising utilization of CoPy/C as electrocatalysts for alkaline polymer electrolyte membrane fuel cells

  14. 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.

  15. Energy efficiency of platinum-free alkaline direct formate fuel cells

    International Nuclear Information System (INIS)

    Wang, L.Q.; Bellini, M.; Filippi, J.; Folliero, M.; Lavacchi, A.; Innocenti, M.; Marchionni, A.; Miller, H.A.; Vizza, F.

    2016-01-01

    Highlights: • Alkaline Platinum-free formate fuel cells top 42% efficiency @ 60 °C. • Palladium efficiently oxidizes formate. • Power density exceeding 250 mW cm −2 @ 60 °C has been achieved. • Performance exceeds that of Alkaline Direct Alcohol Fuel Cell. - Abstract: We report the energy performance of a new platinum-free alkaline direct formate fuel cell, equipped with a commercial anion exchange membrane, a nanostructured Pd/C anode and a Fe–Co/C cathode. The cell was investigated both at room temperature and at 60 °C for the determination of the following parameters: (i) maximum power density, (ii) delivered energy, (iii) faradic (fuel conversion) and energy efficiency. These parameters show a dramatic dependence on fuel composition. The highest energy efficiency is obtained using high energy density fuel (4 M KCOOH and 4 M KOH) and with a maximum operating temperature of 60 °C. This represents a key step in the progress of alkaline platinum-free DFFC technology, demonstrating their potential as power sources for portable electronic devices and remote power generation systems. For example, a fuel load of 750 ml in a DFFC device operating at 60 °C would be able to produce 90 W h of energy, that required to fully charge the battery of a laptop computer.

  16. Efficiency of Polymer Electrolyte Membrane Fuel Cell Stack

    Directory of Open Access Journals (Sweden)

    Hans Bosma

    2011-08-01

    Full Text Available This paper applies a feedforward control of optimal oxygen excess ratio that maximize net power (improve efficiency of a NedStack P8.0-64 PEM fuel cell stack (FCS system. Net powers profile as a function of oxygen excess ratio for some points of operation are analyzed by using FCS model. The relationships between stack current and the corresponding control input voltage that gives an optimal oxygen excess ratio are used to design a feedforward control scheme. The results of this scheme are compared to the results of a feedforward control using a constant oxygen excess ratio. Simulation results show that optimal oxygen excess ratio improves fuel cell performance compared to the results of constant oxygen excess ratio. The same procedures are performed experimentally for the FCS system. The behaviour of the net power of the fuel cell stack with respect to the variation of oxygen excess ratio is analyzed to obtain optimal values. Data of stack current and the corresponding voltage input to the compressor that gives optimal values of oxygen excess ratio are used to develop a feedforward control. Feedforward control based on constant and optimal oxygen excess ratio control, are implemented in the NedStack P8.0-64 PEM fuel cell stack system by using LabVIEW. Implementation results shows that optimal oxygen excess ratio control improves the fuel cell performance compared to the constant oxygen excess ratio control.

  17. Anion exchange membrane based on alkali doped poly(2,5-benzimidazole) for alkaline membrane fuel cell

    CSIR Research Space (South Africa)

    Luo, H

    2010-03-01

    Full Text Available Alkaline membrane fuel cell (AMFC) has been received increasing attention among the different types of fuel cells. Ammonium quaternized polymers such as poly (arylene ether sulfones) are being developed and studied as candidates of ionomeric...

  18. Fabric-based alkaline direct formate microfluidic fuel cells.

    Science.gov (United States)

    Domalaon, Kryls; Tang, Catherine; Mendez, Alex; Bernal, Franky; Purohit, Krutarth; Pham, Linda; Haan, John; Gomez, Frank A

    2017-04-01

    Fabric-based microfluidic fuel cells (MFCs) serve as a novel, cost-efficient alternative to traditional FCs and batteries, since fluids naturally travel across fabric via capillary action, eliminating the need for an external pump and lowering production and operation costs. Building on previous research with Y-shaped paper-based MFCs, fabric-based MFCs mitigate fragility and durability issues caused by long periods of fuel immersion. In this study, we describe a microfluidic fabric-based direct formate fuel cell, with 5 M potassium formate and 30% hydrogen peroxide as the anode fuel and cathode oxidant, respectively. Using a two-strip, stacked design, the optimized parameters include the type of encasement, the barrier, and the fabric type. Surface contact of the fabric and laminate sheet expedited flow and respective chemical reactions. The maximum current (22.83 mA/cm 2 ) and power (4.40 mW/cm 2 ) densities achieved with a 65% cotton/35% polyester blend material are a respective 8.7% and 32% higher than previous studies with Y-shaped paper-based MFCs. In series configuration, the MFCs generate sufficient energy to power a handheld calculator, a thermometer, and a spectrum of light-emitting diodes. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Study of ceria-carbonate nanocomposite electrolytes for low-temperature solid oxide fuel cells.

    Science.gov (United States)

    Fan, L; Wang, C; Di, J; Chen, M; Zheng, J; Zhu, B

    2012-06-01

    Composite and nanocomposite samarium doped ceria-carbonates powders were prepared by solid-state reaction, citric acid-nitrate combustion and modified nanocomposite approaches and used as electrolytes for low temperature solid oxide fuel cells. X-ray Diffraction, Scanning Electron Microscope, low-temperature Nitrogen Adsorption/desorption Experiments, Electrochemical Impedance Spectroscopy and fuel cell performance test were employed in characterization of these materials. All powders are nano-size particles with slight aggregation and carbonates are amorphous in composites. Nanocomposite electrolyte exhibits much lower impedance resistance and higher ionic conductivity than those of the other electrolytes at lower temperature. Fuel cell using the electrolyte prepared by modified nanocomposite approach exhibits the best performance in the whole operation temperature range and achieves a maximum power density of 839 mW cm(-2) at 600 degrees C with H2 as fuel. The excellent physical and electrochemical performances of nanocomposite electrolyte make it a promising candidate for low-temperature solid oxide fuel cells.

  20. Evaluation of an alkaline fuel cell system as a micro-CHP

    International Nuclear Information System (INIS)

    Verhaert, Ivan; Mulder, Grietus; De Paepe, Michel

    2016-01-01

    Highlights: • Sensitivity analysis on system configuration of the AFC as a micro-CHP. • Flow rate in the secondary heating circuit can be used to control water management. • Part load behavior of fuel cells is compared to other micro-CHP technologies. • For future energy demand in buildings fuel cells have the best performance. - Abstract: Micro-cogeneration is an emerging technology to reduce the non-renewable energy demand in buildings and reduce peak load in the grid. Fuel cell based cogeneration (CHP) has interesting prospects for building applications, even at relatively low heat demand. This is due to their partial load behavior which is completely different, compared to other micro-CHP technologies. Within the fuel cell technologies suitable for small scale CHP or micro-CHP, the existing configuration of an alkaline fuel cell system is analyzed. This analysis is based on validated models and offers a control strategy to optimize both water management and energy performance of the alkaline fuel cell system. Finally, the model of the alkaline fuel cell system with optimized control strategy is used to compare its part load behavior to other micro-CHP technologies.

  1. 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...

  2. IrPdRu/C as H2Oxidation Catalysts for Alkaline Fuel Cells.

    Science.gov (United States)

    Wang, Hongsen; Abruña, Héctor D

    2017-05-24

    H 2 oxidation kinetics on Pt in alkaline media are very sluggish, being over 100 times slower than in acidic media, and thus, new and more active H 2 oxidation electrocatalysts must be developed in order to enable alkaline exchange membrane fuel cells (AEMFCs). In this Communication, we present a new type of catalysts-carbon-supported IrPdRu nanoparticles-as H 2 oxidation catalysts in alkaline media. These catalysts exhibit higher activity than Pt/C and Ir/C catalysts and are also quite stable. In particular, Ir 3 Ru 7 /C and Ir 3 Pd 1 Ru 6 /C catalysts are significantly more active and less expensive than Pt/C and Ir/C, and are thus promising new anode catalysts for alkaline fuel cell applications.

  3. Radiolytic synthesis and characterization of PVA and chitosan based conductive polymer membranes for alkaline fuel cells

    Directory of Open Access Journals (Sweden)

    Stoševski Ivan D.

    2014-01-01

    Full Text Available Poly(vinyl alcohol (PVA and chitosan (CS based polymer membranes for alkaline fuel cells were synthesized by gamma irradiation method. They were swollen with 6 M KOH solution and their ionic conductivity and gas permeance were investigated as a function of temperature. They show high ionic conductivities at room temperature, which wasn't reduced over a period of few months. No gas flow through membranes was detected at any temperature and pressure. These properties show that the membranes could be potentially applied in alkaline fuel cells.

  4. 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.)

  5. 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.

  6. An electro-kinetic study of oxygen reduction in polymer electrolyte fuel cells at intermediate temperatures

    OpenAIRE

    Gatto, I.; Stassi, A.; Passalacqua, E.; Arico, A. S.

    2013-01-01

    International audience; The oxygen reduction process in polymer electrolyte fuel cells (PEMFCs) was in-situ investigated at intermediate temperatures (80 e130 C) by using a carbon supported PtCo catalyst and Nafion membrane as electrolyte. To overcome the Nafion dehydration above 100 C, the experiments were carried out under pressurized conditions. Electro-kinetic parameters such as reaction order and activation energy were determined from the steady-state galvanostatic polarization curves ob...

  7. Development of high-performance polymer electrolyte membranes for direct methanol fuel cells

    Science.gov (United States)

    Atti, Anthony Richard

    2000-10-01

    Direct oxidation fuel cells based on polymer electrolyte membranes have long been viewed as a method of power generation. The development of a methanol based-liquid feed system has further reduced system complexity and offered promising electrical performance at low temperatures utilizing ambient pressure air as the oxidant. USC and JPL in a collaborative approach sponsored by DARPA have pursued the development of novel polymer electrolyte membranes consisting of a semi-sequential interpenetrating polymer network of polyvinyldifluoride (PVDF) and polystyrene-sulfonic acid (PSSA) to be used in Direct Methanol Fuel Cells. A suitable precursor material has been identified and polymerization conditions optimized resulting in the preparation of polymer electrolyte membranes with preferred surface morphology and favorable fuel cell-related characteristics. Reduced methanol crossover and promising electrical performance, comparable to state-of-art materials characterize the polymer electrolyte membranes and translate into favorable fuel cell efficiency values. This research was initiated in order to identify an alternative polymer electrolyte membrane capable of superior electrical performance and low methanol crossover in an attempt to construct an efficient, lightweight 150 W portable power system.

  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

  9. 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.

  10. Design and Test of a Carbon-Tolerant Alkaline Fuel Cell

    OpenAIRE

    Urquidi-Macdonald, Mirna; Sen, Ayusman; Grimes, Patrick; Tewari, Ashutosh; Sambhy, Varun

    2005-01-01

    This paper presents new results which may constitute a breakthrough in the effort to develop fuel cells truly suitable for use in cars and trucks. For decades, researchers have known that the alkaline fuel cell (AFC) is much cheaper to make, more efficient and more durable than the more popular PEM fuel cell; however, "carbon poisoning" (either from CO2 in air or from contaminants in reformed methanol) causes big problems in the kind of oxygen-hydrogen AFC commonly used in space. This paper r...

  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. 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)

  13. 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...... emerge and be entrained into the gas stream....

  14. Numerical studies on liquid water flooding in gas channels used inpolymer electrolyte fuel cells

    NARCIS (Netherlands)

    Qin, CZ.; Hassanizadeh, S.M.; Rensink, D.

    2012-01-01

    Water management plays an important role in the development of low-temperature polymer electrolyte fuel cells (PEFCs). The lack of a macroscopic gas channel (GC) flooding model constrains the current predictions of PEFC modeling under severe flooding situations. In this work, we have extended our

  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. Polypropylene oil as fuel for solid oxide fuel cell with samarium doped-ceria (SDC)-carbonate as electrolyte

    Science.gov (United States)

    Syahputra, R. J. E.; Rahmawati, F.; Prameswari, A. P.; Saktian, R.

    2017-03-01

    The research focusses on converting polypropylene oil as pyrolysis product of polypropylene plastic into an electricity. The converter was a direct liquid fuel-solid oxide fuel cell (SOFC) with cerium oxide based material as electrolyte. The polypropylene vapor flowed into fuel cell, in the anode side and undergo oxidation reaction, meanwhile, the Oxygen in atmosphere reduced into oxygen ion at cathode. The fuel cell test was conducted at 400 - 600 °C. According to GC-MS analysis, the polypropylene oil consist of C8 to C27 hydrocarbon chain. The XRD analysis result shows that Na2CO3 did not change the crystal structure of SDC even increases the electrical conductivity. The maximum power density is 0.079 mW.cm-2 at 773 K. The open circuite voltage is 0.77 volt. Chemical stability test by analysing the single cell at before and after fuel cell test found that ionic migration occured during fuel cell operation. It is supported by the change of elemental composition in the point position of electrolyte and at the electrolyte-electrode interface

  17. Characterization of electrode-electrolyte interface in solid oxide fuel cell

    International Nuclear Information System (INIS)

    Lenka, R.K.; Mahata, T.; Sinha, P.K.; Tyagi, A.K.

    2010-01-01

    Full text: Solid oxide fuel cell (SOFC) is an electrochemical device in which chemical energy of fuel, such as, hydrogen, is directly converted to electrical energy in an efficient and environment-friendly manner.The SOFC is primarily a multi-layer structure in which impervious solid oxide electrolyte is sandwiched between porous electrodes. For good performance the cell resistance should be reasonably low. The internal resistance of a working cell is primarily determined by the resistance of the electrolyte layer and the resistances at the electrode - electrolyte interfaces. The later is dependent on the catalytic activity of the electrode material for the corresponding electrode reaction and the interface microstructure in terms of length of the triple phase boundary (TBP). The ceramic fabrication technique plays an important role in determining the interfacial microstructure and hence, the overall performance of a cell. In the present study, gadolinium cobaltate based cathode material and nickel-gadolinia doped ceria (Ni-GDC) composite anode material have been synthesized and integrated with GDC electrolyte. The interfacial microstructures have been studied by scanning electron microscopy (SEM). The area specific resistance (ASR) at the electrode-electrolyte interfaces have been evaluated by electrochemical impedance spectroscopy (EIS) using symmetrical cell. Using our optimum processing technique ASR values of 0.41 U.cm 2 and 0.03 U.cm 2 have been obtained at Ba-doped GdCoO 3 /GDC interface and Ni-GDC/GDC interface respectively at 900 deg C

  18. Alkaline anion exchange membrane fuel cells for cogeneration of electricity and valuable chemicals

    Science.gov (United States)

    Pan, Z. F.; Chen, R.; An, L.; Li, Y. S.

    2017-10-01

    Alkaline anion exchange membrane fuel cells (AAEMFCs) have received ever-increasing attentions due to the enhanced electrochemical kinetics and the absence of precious metal electrocatalysts, and thus great progress has been made in recent years. The alkaline anion exchange membrane based direct alcohol fuel cells, one type of alkaline anion exchange membrane fuel cells utilizing liquid alcohols as fuel that can be obtained from renewable biomass feedstocks, is another attractive point due to its ability to provide electricity with cogeneration of valuable chemicals. Significant development has been made to improve the selectivity towards high added-value chemicals and power output in the past few years. This review article provides a general description of this emerging technology, including fuel-cell setup and potential reaction routes, summarizes the products, performance, and system designs, as well as introduces the application of this concept in the removal of heavy-metal ions from the industrial wastewater. In addition, the remaining challenges and perspectives are also highlighted.

  19. 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.

  20. 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

  1. 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

  2. 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}.

  3. A small-scale flow alkaline fuel cell for on-site production of hydrogen peroxide

    International Nuclear Information System (INIS)

    Brillas, Enric; Alcaide, Francisco; Cabot, Pere-Lluis

    2002-01-01

    The behavior of a small-scale flow alkaline fuel cell (AFC) built-up for on-site production of HO 2 - using commercial gas-diffusion electrodes has been studied. It produces a spontaneous current due to the oxidation of H 2 to H 2 O at the H 2 -diffusion anode and the reduction of O 2 to HO 2 - at the O 2 -diffusion cathode, while a fresh 1.0-6.0 mol dm -3 KOH electrolyte at 15.0-45.0 deg. C is injected through it. Under circulation of HO 2 - +KOH solutions in open circuit, the flow AFC behaves as a two-electron reversible system. When it is shorted with an external load (R ext ), steady cell voltage-current density curves are found. The use of O 2 /N 2 mixtures to fed the cathode causes a loss of its performance, being required to supply pure O 2 to yield a maximum HO 2 - electrogeneration. The current density and HO 2 - productivity increase with raising OH - concentration, temperature and pressure of O 2 fed. At R ext =0.10 Ω, a current efficiency close to 100% is obtained, and current densities >100 mA cm -2 are achieved for 1.0 mol dm -3 KOH at 45.0 deg. C and for higher KOH concentrations at 25.0 deg. C. The flow AFC can work under optimum conditions up to 6.0 mol dm -3 KOH and 45.0 deg. C for possible industrial applications

  4. 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.

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

    Science.gov (United States)

    Raza, Rizwan; Ahmed, Akhlaq; Akram, Nadeem; Saleem, Muhammad; Niaz Akhtar, Majid; Sherazi, Tauqir A.; Ajmal Khan, M.; Abbas, Ghazanfar; Shakir, Imran; Mohsin, Munazza; Alvi, Farah; Javed, Muhammad Sufyan; Yasir Rafique, M.; Zhu, Bin

    2015-11-01

    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.

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

    OpenAIRE

    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 critical to the operation of PEFCs, since the membrane needs to attain sufficient water for effective ionic conduction. On the other hand, too much water accumulating in PEFCs would result in mass tra...

  7. Macroscopic analysis of characteristic water transport phenomena in polymer electrolyte fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Hye-Mi [Graduate School, Department of Mechanical Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea); Lee, Kwan-Soo; Um, Sukkee [School of Mechanical Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea)

    2008-04-15

    Comprehensive analytical and numerical analyses were performed, focusing on anode water loss, cathode flooding, and water equilibrium for polymer electrolyte fuel cells. General features of water transport as a function of membrane thickness and current density were presented to illustrate the net effect of back-diffusion of water from the cathode to anode over a polymer electrolyte fuel cell domain. First, two-dimensional numerical simulation were performed, showing that the difference in molar concentration of water at the channel outlet is widened as the operating current density increases with a thin membrane (Nafion {sup registered} 111), which was verified by Dong et al. [Distributed performance of polymer electrolyte fuel cells under low-humidity conditions. J Electrochem Soc 2005; 152: A2114-22]. Then, analytical solutions were compared with computational results in predicting those characteristics of water transport phenomena. It was theoretically estimated that the high pressure operation of fuel cells expedites water condensing and results in shorter anode water loss and cathode flooding locations. In this study, it was also found that a thin membrane (Nafion {sup registered} 111) facilitates water transport in the through-membrane direction and therefore water concentration at the anode and cathode channel outlets reaches an equilibrium state particularly at low operating current densities. Moreover, the difference in the anode water concentration between Nafion {sup registered} 111 and Nafion {sup registered} 115 membranes becomes intensified in the in-plane direction under the same water production condition, while the cathode water concentration profiles remains almost same. (author)

  8. 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.

  9. 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)

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

    International Nuclear Information System (INIS)

    Nascimento, Ana P.; Linares, Jose J.

    2014-01-01

    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 -1 glycerol and 4 mol L -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 -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 3 Sn/C) is beneficial for increasing the cell performance. (author)

  11. Study on Zinc Oxide-Based Electrolytes in Low-Temperature Solid Oxide Fuel Cells.

    Science.gov (United States)

    Xia, Chen; Qiao, Zheng; Feng, Chu; Kim, Jung-Sik; Wang, Baoyuan; Zhu, Bin

    2017-12-28

    Semiconducting-ionic conductors have been recently described as excellent electrolyte membranes for low-temperature operation solid oxide fuel cells (LT-SOFCs). In the present work, two new functional materials based on zinc oxide (ZnO)-a legacy material in semiconductors but exceptionally novel to solid state ionics-are developed as membranes in SOFCs for the first time. The proposed ZnO and ZnO-LCP (La/Pr doped CeO₂) electrolytes are respectively sandwiched between two Ni 0.8 Co 0.15 Al 0.05 Li-oxide (NCAL) electrodes to construct fuel cell devices. The assembled ZnO fuel cell demonstrates encouraging power outputs of 158-482 mW cm -2 and high open circuit voltages (OCVs) of 1-1.06 V at 450-550 °C, while the ZnO-LCP cell delivers significantly enhanced performance with maximum power density of 864 mW cm -2 and OCV of 1.07 V at 550 °C. The conductive properties of the materials are investigated. As a consequence, the ZnO electrolyte and ZnO-LCP composite exhibit extraordinary ionic conductivities of 0.09 and 0.156 S cm -1 at 550 °C, respectively, and the proton conductive behavior of ZnO is verified. Furthermore, performance enhancement of the ZnO-LCP cell is studied by electrochemical impedance spectroscopy (EIS), which is found to be as a result of the significantly reduced grain boundary and electrode polarization resistances. These findings indicate that ZnO is a highly promising alternative semiconducting-ionic membrane to replace the electrolyte materials for advanced LT-SOFCs, which in turn provides a new strategic pathway for the future development of electrolytes.

  12. High-performance alkaline direct methanol fuel cell using a nitrogen-postdoped anode.

    Science.gov (United States)

    Joghee, Prabhuram; Pylypenko, Svitlana; Wood, Kevin; Bender, Guido; O'Hayre, Ryan

    2014-07-01

    A commercial PtRu/C catalyst postdoped with nitrogen demonstrates a significantly higher performance (~10-20% improvement) in the anode of an alkaline direct methanol fuel cell than an unmodified commercial PtRu/C catalyst control. The enhanced performance shown herein is attributed at least partially to the increased electrochemical surface area of the PtRu/C after postdoping with nitrogen. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. High temperature polymer electrolyte membrane fuel cells: Approaches, status, and perspectives

    DEFF Research Database (Denmark)

    This book is a comprehensive review of high-temperature polymer electrolyte membrane fuel cells (PEMFCs). PEMFCs are the preferred fuel cells for a variety of applications such as automobiles, cogeneration of heat and power units, emergency power and portable electronics. The first 5 chapters...... of and motivated extensive research activity in the field. The last 11 chapters summarize the state-of-the-art of technological development of high temperature-PEMFCs based on acid doped PBI membranes including catalysts, electrodes, MEAs, bipolar plates, modelling, stacking, diagnostics and applications....

  14. Application of the nanocomposite membrane as electrolyte of proton exchange membrane fuel cell

    International Nuclear Information System (INIS)

    Mahreni

    2010-01-01

    Hydrogen fuel cells proton exchange membrane fuel cell (PEMFC) is currently still in development and commercialization. Several barriers to the commercialization of these Nafion membrane as electrolyte is its very sensitive to humidity fluctuation. Nafion must be modified by making a composite Nafion-SiO 2 -HPA to increase electrolyte resistance against humidity fluctuations during the cell used. Research carried out by mixing Nafion solution with Tetra Ethoxy Ortho Silicate (TEOS) and conductive materials is phosphotungstic acid (PWA) by varying the ratio of Nafion, TEOS and PWA. The membrane is produced by heating a mixture of Nafion, TEOS and PWA by varying the evaporation temperature, time and annealing temperature to obtain the transparent membrane. The resulting membrane was analyzed its physical, chemical and electrochemical properties by applying the membrane as electrolyte of PEMFC at various humidity and temperature of operation. The results showed that at low temperatures (30-90 °C) and high humidity at 100 % RH, pure Nafion membrane is better than composite membrane (Nafion-SiO 2 -PWA), but at low humidity condition composite membrane is better than the pure Nafion membrane. It can be concluded that the composite membranes of (Nafion-SiO 2 -PWA) can be used as electrolyte of PEMFC operated at low humidity (40 % RH) and temperature between (30-90 °C). (author)

  15. Hydrogen production by steam reforming methanol for polymer electrolyte fuel cells

    International Nuclear Information System (INIS)

    Amphlett, J.C.; Creber, K.A.M.; Davis, J.M.; Mann, R.F.; Peppley, B.A.; Stokes, D.M.

    1993-01-01

    Catalytic steam reforming of methanol has been studied as a means of generating hydrogen for a polymer electrolyte membrane fuel cell. A semi-empirical model of the kinetics of the catalytic steam reforming of methanol over Cu O/Zn O/Al 2 O 3 catalyst has been developed. This model is able to predict the performance of the reformer with respect to the various parameters important in developing an integrated reformer-polymer fuel cell system. A set of sample calculations of reformer temperature and CO production are given. The impact of the performance of the reformer catalyst on the design of the overall fuel cell power system is discussed. The selectivity of the catalyst to minimize CO content in the fuel gas is shown to be more critical than was previously believed. 4 figs., 4 tabs., 11 refs

  16. High temperature polymer electrolyte membrane fuel cells: Approaches, status, and perspectives

    DEFF Research Database (Denmark)

    This book is a comprehensive review of high-temperature polymer electrolyte membrane fuel cells (PEMFCs). PEMFCs are the preferred fuel cells for a variety of applications such as automobiles, cogeneration of heat and power units, emergency power and portable electronics. The first 5 chapters...... of the book describe rationalization and illustration of approaches to high temperature PEM systems. Chapters 6 - 13 are devoted to fabrication, optimization and characterization of phosphoric acid-doped polybenzimidazole membranes, the very first electrolyte system that has demonstrated the concept...... of and motivated extensive research activity in the field. The last 11 chapters summarize the state-of-the-art of technological development of high temperature-PEMFCs based on acid doped PBI membranes including catalysts, electrodes, MEAs, bipolar plates, modelling, stacking, diagnostics and applications....

  17. Characterization of anion exchange ionomers in hybrid polymer electrolyte fuel cells.

    Science.gov (United States)

    Unlü, Murat; Zhou, Junfeng; Anestis-Richard, Irene; Kohl, Paul A

    2010-12-17

    Anion exchange ionomers (AEI) synthesized here were characterized by use of a novel fuel cell configuration. The new analysis method involves assembling the AEI electrode of interest as the cathode in a hybrid, acid/alkaline, fuel cell configuration. The hybrid cell includes a conventional proton conducting anode/membrane half-cell along with the anionic conductor of interest at the cathode. Electrochemical impedance spectroscopy and voltammetry were used to evaluate the performance of the hybrid AEI-containing fuel cell with H₂ and O₂. In particular, the AEI electrode response in impedance spectroscopy was easily identified because the contributions from other components are largely minimized in the presented hybrid cell configuration. The properties of ionomers used in the AEI electrode were shown to have a substantial effect on the electrode performance. Low catalyst utilization, due to high water uptake and low conductivity, was identified as the major causes of poor performance in AEI electrodes.

  18. A membraneless microscale fuel cell using non-noble catalysts in alkaline solution

    Science.gov (United States)

    Sung, Woosuk; Choi, Jin-Woo

    This paper presents the development of a novel liquid-based microscale fuel cell using non-noble catalysts in an alkaline solution. The developed fuel cell is based on a membraneless structure. The operational complications of a proton exchange membrane lead the development of a fuel cell with the membraneless structure. Non-noble metals with relatively mild catalytic activity, nickel hydroxide and silver oxide, were employed as anode and cathode catalysts to minimize the effect of cross-reactions with the membraneless structure. Along with nickel hydroxide and silver oxide, methanol and hydrogen peroxide were used as a fuel at anode and an oxidant at cathode. With a fuel mixture flow rate of 200 μl min -1, a maximum output power density of 28.73 μW cm -2 was achieved. The developed fuel cell features no proton exchange membrane, inexpensive catalysts, and simple planar structure, which enables high design flexibility and easy integration of the microscale fuel cell into actual microfluidic systems and portable applications.

  19. High resolution neutron imaging of water in the polymer electrolyte fuel cell membrane

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, Partha P [Los Alamos National Laboratory; Makundan, Rangachary [Los Alamos National Laboratory; Spendelow, Jacob S [Los Alamos National Laboratory; Borup, Rodney L [Los Alamos National Laboratory; Hussey, D S [NIST; Jacobson, D L [NIST; Arif, M [NIST

    2009-01-01

    Water transport in the ionomeric membrane, typically Nafion{reg_sign}, has profound influence on the performance of the polymer electrolyte fuel cell, in terms of internal resistance and overall water balance. In this work, high resolution neutron imaging of the Nafion{reg_sign} membrane is presented in order to measure water content and through-plane gradients in situ under disparate temperature and humidification conditions.

  20. 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.

  1. Modeling of Ultrathin Catalyst Layers in Polymer Electrolyte Fuel Cells: Proton Transport and Water Management

    OpenAIRE

    Chan, Karen Ka Wing

    2013-01-01

    Ultrathin catalyst layers (UTCLs) are emerging as a promising alternative to conventional catalyst layers in polymer electrolyte fuel cells. In comparison, UTCLs have dramatically reduced Pt loading and thicknesses and are ionomer–free. We explore two open questions in the theory of UTCLs (1) the proton transport mechanism within the ionomer–free layer and (2) water management in membrane electrode assemblies (MEAs) with UTCLs. To investigate (1), we present a UTCL model, which assumes the pr...

  2. Emerging methanol-tolerant AlN nanowire oxygen reduction electrocatalyst for alkaline direct methanol fuel cell.

    Science.gov (United States)

    Lei, M; Wang, J; Li, J R; Wang, Y G; Tang, H L; Wang, W J

    2014-08-11

    Replacing precious and nondurable Pt catalysts with cheap materials is a key issue for commercialization of fuel cells. In the case of oxygen reduction reaction (ORR) catalysts for direct methanol fuel cell (DMFC), the methanol tolerance is also an important concern. Here, we develop AlN nanowires with diameters of about 100-150 nm and the length up to 1 mm through crystal growth method. We find it is electrochemically stable in methanol-contained alkaline electrolyte. This novel material exhibits pronounced electrocatalytic activity with exchange current density of about 6.52 × 10(-8) A/cm(2). The single cell assembled with AlN nanowire cathodic electrode achieves a power density of 18.9 mW cm(-2). After being maintained at 100 mA cm(-2) for 48 h, the AlN nanowire-based single cell keeps 92.1% of the initial performance, which is in comparison with 54.5% for that assembled with Pt/C cathode. This discovery reveals a new type of metal nitride ORR catalyst that can be cheaply produced from crystal growth method.

  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. Atomistic Modeling in Study of Polymer Electrolyte Fuel Cells - A Review

    Science.gov (United States)

    Zhou, Xiangyang; Zhou, Juanjuan; Yin, Yijin

    Polymer electrolyte fuel cell (PEFC) is considered as one of the most promising power sources for futurist's hydrogen economy. As shown in Fig. 1, operation of a Nafion-based PEFC is dictated by transport processes and electrochemical reactions at catalyst/polymer electrolyte interfaces and transport processes in the polymer electrolyte membrane (PEM), in the catalyst layers consisting of precious metal (Pt or Ru) catalysts on porous carbon support and polymer electrolyte clusters, in gas diffusion layers (GDLs), and in flow channels. Specifically, oxidants, fuel, and reaction products flow in channels of millimeter scale and diffuse in GDL with a structure of micrometer scale. Nafion, a sulfonic acid tetrafluorethylene copolymer and the most commonly used polymer electrolyte, consists of nanoscale hydrophobic domains and proton conducting hydrophilic domains with a scale of 2-5 nm. The diffusivities of the reactants (O2, H2, and methanol) and reaction products (water and CO2) in Nafion and proton conductivity of Nafion strongly depend on the nanostructures and their responses to the presence of water. Polymer electrolyte clusters in the catalyst layers also play a critical role in the catalysis of the nano-sized Pt catalysts. Electrochemical reactions occur at the interfaces between catalysts (Pt or Pt/Ru) and Nafion. The catalytic activity of the Pt catalysts is believed to be dictated by transport processes, adsorption/desorption, and charge transfer in the interfacial area. While transport processes may occur in an area of a few nanometers, adsorption/desorption and charge transfer occur within a region of a few angstroms from the surface of a nano-particulate catalyst. Thus, modeling or simulation of PEFC is a multiscale problem.

  5. 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.

  6. Neutron Computed Tomography of Freeze/thaw Phenomena in Polymer Electrolyte Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Matthew M. Mech; Jack Brenizer; Kenan Unlu; A.K. Heller

    2008-12-12

    This report summarizes the final year's progress of the three-year NEER program. The overall objectives of this program were to 1) design and construct a sophisticated hight-resolution neutron computed tomography (NCT) facility, 2) develop novel and sophisticated liquid water and ice quantification analysis software for computed tomography, and 3) apply the advanced software and NCT capability to study liquid and ice distribution in polymer electrolyte fuel cells (PEFCs) under cold-start conditions. These objectives have been accomplished by the research team, enabling a new capability for advanced 3D image quantification with neutron imaging for fuel cell and other applications. The NCT water quantification methodology and software will greatly add to the capabilities of the neutron imaging community, and the quantified liquid water and ice distribution provided by its application to PEFCs will enhance understanding and guide design in the fuel cell community.

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

    International Nuclear Information System (INIS)

    Inagaki, Toru; Nishiwaki, Futoshi; Kanou, Jirou; Yamasaki, Satoru; Hosoi, Kei; Miyazawa, Takashi; Yamada, Masaharu; Komada, Norikazu

    2006-01-01

    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 o C 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)O 3-δ , Ni-(CeO 2 ) 1-x (SmO 1.5 ) x cermet anode, and Sm(Sr)CoO 3-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 o C was obtained using high temperature off-gas from SOFC

  8. Ultrasonic synthesis and evaluation of non-platinum catalysts for alkaline direct methanol fuel cells

    Science.gov (United States)

    Bunazawa, Hideaki; Yamazaki, Yohtaro

    Ultrasonic synthesis was investigated as a synthesis method of non-platinum catalysts for alkaline direct methanol fuel cells (alkaline DMFCs) such as 20% mass Pd/C, Au/C, and PdAu/C. Among four kinds of solvents, ethylene glycol was demonstrated to be the optimum solvent for the synthesis of those catalysts. When ethylene glycol was used, the synthesized metal nanoparticles were highly dispersed on carbon particles. The synthesized Pd/C and PdAu/C showed the high oxygen reduction reaction (ORR) activity in alkaline condition (0.5 M NaOH aqueous solution), which was comparable to conventional Pt/C. Moreover, they showed lower methanol oxidation reaction (MOR) activity. Membrane electrode assemblies (MEAs) containing the synthesized Pd/C cathode catalysts and alkaline ion exchange membranes were fabricated and evaluated by single cell tests. They showed high performance that was comparable to MEAs with Pt/C cathode. In addition, it was found that the synthesized Pd/C was relatively tolerant to methanol crossover.

  9. 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...

  10. A Review on the Fabrication of Electro spun Polymer Electrolyte Membrane for Direct Methanol Fuel Cell

    International Nuclear Information System (INIS)

    Junoh, H.; Jaafar, J.; Norddin, M.N.A.M.; Ismail, A.F.; Othman, M.H.D.; Rahman, M.A.; Yusof, N.; Salleh, W.N.W.; Junoh, H.; Jaafar, J.; Norddin, M.N.A.M.; Ismail, A.F.; Othman, M.H.D.; Rahman, M.A.; Yusof, N.; Salleh, W.N.W.; Hamid Ilbeygi, H.

    2014-01-01

    Proton exchange membrane (PEM) is an electrolyte which behaves as important indicator for fuel cell’s performance. Research and development (R and D) on fabrication of desirable PEM have burgeoned year by year, especially for direct methanol fuel cell (DMFC). However, most of the R and Ds only focus on the parent polymer electrolyte rather than polymer inorganic composites. This might be due to the difficulties faced in producing good dispersion of inorganic filler within the polymer matrix, which would consequently reduce the DMFC’s performance. Electro spinning is a promising technique to cater for this arising problem owing to its more widespread dispersion of inorganic filler within the polymer matrix, which can reduce the size of the filler up to nano scale. There has been a huge development on fabricating electrolyte nano composite membrane, regardless of the effect of electro spun nano composite membrane on the fuel cell’s performance. In this present paper, issues regarding the R and D on electro spun sulfonated poly (ether ether ketone) (SPEEK)/inorganic nano composite fiber are addressed.

  11. A Review on the Fabrication of Electrospun Polymer Electrolyte Membrane for Direct Methanol Fuel Cell

    Directory of Open Access Journals (Sweden)

    Hazlina Junoh

    2015-01-01

    Full Text Available Proton exchange membrane (PEM is an electrolyte which behaves as important indicator for fuel cell’s performance. Research and development (R&D on fabrication of desirable PEM have burgeoned year by year, especially for direct methanol fuel cell (DMFC. However, most of the R&Ds only focus on the parent polymer electrolyte rather than polymer inorganic composites. This might be due to the difficulties faced in producing good dispersion of inorganic filler within the polymer matrix, which would consequently reduce the DMFC’s performance. Electrospinning is a promising technique to cater for this arising problem owing to its more widespread dispersion of inorganic filler within the polymer matrix, which can reduce the size of the filler up to nanoscale. There has been a huge development on fabricating electrolyte nanocomposite membrane, regardless of the effect of electrospun nanocomposite membrane on the fuel cell’s performance. In this present paper, issues regarding the R&D on electrospun sulfonated poly (ether ether ketone (SPEEK/inorganic nanocomposite fiber are addressed.

  12. Degradation of some ceria electrolytes under hydrogen contact nearby anode in solid oxide fuel cells (SOFCs

    Directory of Open Access Journals (Sweden)

    Malta Luiz Fernando Brum

    2004-01-01

    Full Text Available This work is concerned with thermodynamic analysis of the stability of some ceria electrolytes under contact with hydrogen gas nearby anode in fuel cells. It was considered the following types of ceria-electrolytes: pure ceria, strontium-doped ceria, calcium-doped ceria and calcium-bismuth-doped ceria. The equilibrium Log (pH2O/pH2 vs. T diagrams were constructed for x = 0.1 and 0.01, where x is the fraction of initial ceria converted to Ce2O3 (proportional to the ratio between activities of Ce3+ and Ce4+ in the ceria electrolyte, which is proportional to the fraction of electronic conduction in the electrolyte at a given temperature. The predictions of the diagrams are as follows: (a Ce1.9Ca0.1Bi0.8O5.1 and Ce0.9Sr0.1O1.9 are less stable than pure ceria for the whole temperature range (from 0 to 1000 °C; (b Ce0.9Ca0.1O1.9 is more stable than pure ceria below about 650 °C for x = 0.1 and below about 400 °C for x = 0.01; (c at each temperature in the considered range the pressure ratio pH2O(g/pH2(g has to be higher than thermodynamically predicted in order to keep CeO2 stable in the electrolyte contacting hydrogen gas. Thermodynamic predictions are entirely capable of explaining experimental data published on the subject (irreversible cell degradation in the case of SrO-doped ceria; weight loss from doped-ceria electrolyte above 700 °C; oxygen gas release during sintering of ceria.

  13. Cogeneration of electricity and organic chemicals using a polymer electrolyte fuel cell

    International Nuclear Information System (INIS)

    Yuan, X.; Ma, Z.; Bueb, H.; Drillet, J.-F.; Hagen, J.; Schmidt, V.M.

    2005-01-01

    Several unsaturated organic alcohols (allyl alcohol, propargyl alcohol, 2-butin-1,4-diol, 2- buten-1,4-diol) and acids (maleic acid, acrylic acid, crotonic acid, acetylendicarboxylic acid) were used as oxidants together with hydrogen as fuel in a polymer electrolyte fuel cell (PEFC). The standard free enthalpies (Δ R G θ ) of the overall fuel cell reactions H 2 /oxidant were calculated to be negative and the equilibrium voltages of such systems are in the range of U 00 = 0.4-0.6 V. In this way, the cogeneration of electric energy and desired hydrogenated products in a fuel cell reactor is apparent. Nafion[reg] 117, as polymer electrolyte, and commercial gas diffusion electrodes (ETEK) with carbon supported Pt were used in a PEFC reactor. The aqueous solutions of unsaturated alcohols and organic acids (c = 1-2 mol dm -3 ) were pumped under ambient pressure through the cathode compartment of the cell whereas hydrogen was fed into the cell at p 0.15 MPa. The open circuit voltages were measured to be in the range of 0.1-0.25 V. Current densities up to 50 mA cm -2 and maximum power densities of around 1 mW cm -2 has been achieved in the case of allyl alcohol, 2-butene-1,4-diol and acrylic acid. HPLC analysis indicates that the double or triple bond in unsaturated alcohols and organic acids is selectively hydrogenated. In addition, the electrochemical behaviour of the alcohols and acids was studied by means of cyclic voltammetry at a smooth polycrystalline Pt electrode in H 2 SO 4 . Reduction reactions were observed at potentials of E < 200 mV versus RHE. It was found that the onset potential for electrochemical hydrogenation of the double and triple bond in the cyclic voltamogram correlates well with the fuel cell performances using these compounds as oxidants

  14. 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.

  15. Pseudo one-dimensional analysis of polymer electrolyte fuel cell cold-start

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, Partha P [Los Alamos National Laboratory; Mukundan, Rangachary [Los Alamos National Laboratory; Borup, Rodney L [Los Alamos National Laboratory; Wang, Yun [NON LANL; Mishlera, Jeff [NON LANL

    2009-01-01

    This paper investigates the electrochemical kinetics, oxygen transport, and solid water formation in polymer electrolyte fuel cell (PEFC) during cold start. Following [Yo Wang, J. Electrochem. Soc., 154 (2007) B1041-B1048], we develop a pseudo one-dimensional analysis, which enables the evaluation of the impact of ice volume fraction and temperature variations on cell performance during cold-start. The oxygen profile, starvation ice volume fraction, and relevant overpotentials are obtained. This study is valuable for studying the characteristics of PEFC cold-start.

  16. Degradation of H3PO4/PBI High Temperature Polymer Electrolyte Membrane Fuel Cell under Stressed Operating Conditions

    DEFF Research Database (Denmark)

    Zhou, Fan

    The Polymer electrolyte membrane (PEM) fuel cells are promising fuel cell technology which can convert the chemical energy in for example hydrogen into electricity efficiently and environmentally friendly. In this work, some degradation issues of the HT-PEM fuel cell are experimentally investigated...... of the HT-PEM fuel cell are studied in the current work. Both in-situ and ex-situ characterization techniques are conducted to gain insight into the degradation mechanisms of the HT-PEM fuel cell under these operating conditions. The experimental results in this work suggest that the presence of methanol...

  17. Development of composite membranes of PVA-TEOS doped KOH for alkaline membrane fuel cell

    International Nuclear Information System (INIS)

    Haryadi,; Sugianto, D.; Ristopan, E.

    2015-01-01

    Anion exchange membranes (AEMs) play an important role in separating fuel and oxygen (or air) in the Alkaline Membrane Fuel Cells. Preparation of hybrid organic inorganic materials of Polyvinylalcohol (PVA) - Tetraethylorthosilicate (TEOS) composite membrane doped KOH for direct alcohol alkaline fuel cell application has been investigated. The sol-gel method has been used to prepare the composite membrane of PVA-TEOS through crosslinking step and catalyzed by concentrated of hydrochloric acid. The gel solution was cast on the membrane plastic plate to obtain membrane sheets. The dry membranes were then doped by immersing in various concentrations of KOH solutions for about 4 hours. Investigations of the cross-linking process and the presence of hydroxyl group were conducted by FTIR as shown for frequency at about 1600 cm −1 and 3300 cm −1 respectively. The degree of swelling in ethanol decreased as the KOH concentration for membrane soaking process increased. The ion exchange capacity (IEC) of the membrane was 0.25meq/g. This composite membranes display significant ionic conductivity of 3.23 x 10 −2 S/cm in deionized water at room temperature. In addition, the morphology observation by scanning electron microscope (SEM) of the membrane indicates that soaking process of membrane in KOH increased thermal resistant

  18. Toward protic ionic liquid and organic ionic plastic crystal electrolytes for fuel cells

    International Nuclear Information System (INIS)

    Rana, Usman Ali; Forsyth, Maria; MacFarlane, Douglas R.; Pringle, Jennifer M.

    2012-01-01

    Highlights: ► Polymer electrolyte membrane fuel cells that can operate above 120 °C, without humidification, would be much more commercially viable. ► Protic ionic liquids and organic ionic plastic crystals are showing increasing promise as anhydrous proton conductors in fuel cells. ► Here we review the recent progress in these two areas. - Abstract: There is increasing demand for the development of anhydrous proton conducting electrolytes, most notably to allow the development of fuel cells that can operate at temperatures above 120 °C, without the need for constant and controlled humidification. The emerging field of protic ionic liquids (PILs) represents a promising new direction for this research and the development of these materials has made significant progress in recent years. In a related but as yet little-explored avenue, proton conducting organic ionic plastic crystals offer the potential advantage of providing a solid state matrix for anhydrous proton conductivity. Here we discuss the recent progress in these areas and identify the key challenges for future research.

  19. Durable and self-hydrating tungsten carbide-based composite polymer electrolyte membrane fuel cells.

    Science.gov (United States)

    Zheng, Weiqing; Wang, Liang; Deng, Fei; Giles, Stephen A; Prasad, Ajay K; Advani, Suresh G; Yan, Yushan; Vlachos, Dionisios G

    2017-09-04

    Proton conductivity of the polymer electrolyte membranes in fuel cells dictates their performance and requires sufficient water management. Here, we report a simple, scalable method to produce well-dispersed transition metal carbide nanoparticles. We demonstrate that these, when added as an additive to the proton exchange Nafion membrane, provide significant enhancement in power density and durability over 100 hours, surpassing both the baseline Nafion and platinum-containing recast Nafion membranes. Focused ion beam/scanning electron microscope tomography reveals the key membrane degradation mechanism. Density functional theory exposes that OH• and H• radicals adsorb more strongly from solution and reactions producing OH• are significantly more endergonic on tungsten carbide than on platinum. Consequently, tungsten carbide may be a promising catalyst in self-hydrating crossover gases while retarding desorption of and capturing free radicals formed at the cathode, resulting in enhanced membrane durability.The proton conductivity of polymer electrolyte membranes in fuel cells dictates their performance, but requires sufficient water management. Here, the authors report a simple method to produce well-dispersed transition metal carbide nanoparticles as additives to enhance the performance of Nafion membranes in fuel cells.

  20. Characterization of transport phenomena in small polymer electrolyte membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Himanen, O.P.

    2008-07-01

    In small fuel cell systems, energy consumption and size of auxiliary devices should be minimized. One option is to use passive controlling methods that rely on material and structural solutions. Therefore it is important to understand transport phenomena occurring in the cells. In this thesis, charge, mass, and heat transport phenomena related to small PEMFCs were studied experimentally and by modeling. A new method was developed for the characterization of water transport properties of polymer electrolyte membrane under realistic operating conditions. The method was used to evaluate the diffusion coefficient of water in the membrane. Due to channelrib structure, cell components are inhomogeneously compressed. Charge and mass transport parameters were experimentally evaluated as a function of compression. The effect of inhomogeneous compression on cell operation was studied by modeling. Inhomogeneous compression does not significantly affect the polarization behavior of the cell, but it creates uneven current and temperature distributions inside the cell. This affects both cell performance and lifetime and should not be ignored in cell design and modeling. The operation of a freebreathing PEMFC was studied at subzero temperatures. To be able to operate at low temperatures, current density must be high enough to avoid freezing of reactant product water inside the cell. Startup at cold temperatures requires active heating. To maximize fuel efficiency, the operation of a freebreathing PEMFC in dead end mode was investigated. Dead ended operation with periodic purging enables high fuel utilization rate and the test cell operated without significant water management problems or performance loss. (orig.)

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

    Science.gov (United States)

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

    2015-12-08

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

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

    Science.gov (United States)

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

    2015-01-01

    Membrane degradation is a severe factor limiting the lifetime of polymer electrolyte fuel cells. Therefore, obtaining a deeper knowledge is fundamental in order to establish fuel cells as competitive product. A segmented single cell was operated under open circuit voltage with alternating relative humidity. The influence of the catalyst layer on membrane degradation was evaluated by measuring a membrane without electrodes and a membrane-electrode-assembly under identical conditions. After 100 h of accelerated stress testing the proton conductivity of membrane samples near the anode and cathode was investigated by means of ex situ electrochemical impedance spectroscopy. The membrane sample near the cathode inlet exhibited twofold lower membrane resistance and a resulting twofold higher proton conductivity than the membrane sample near the anode inlet. The results from the fluoride ion analysis have shown that the presence of platinum reduces the fluoride emission rate; which supports conclusions drawn from the literature. PMID:26670258

  3. Effects of anode flooding on the performance degradation of polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Kim, Mansu; Jung, Namgee; Eom, KwangSup; Yoo, Sung Jong; Kim, Jin Young; Jang, Jong Hyun; Kim, Hyoung-Juhn; Hong, Bo Ki; Cho, EunAe

    2014-11-01

    Polymer electrolyte membrane fuel cell (PEMFC) stacks in a fuel cell vehicle can be inevitably exposed to harsh environments such as cold weather in winter, causing water flooding by the direct flow of condensed water to the electrodes. In this study, anode flooding was experimentally investigated with condensed water generated by cooling the anode gas line during a long-term operation (∼1600 h). The results showed that the performance of the PEMFC was considerably degraded. After the long-term experiment, the thickness of the anode decreased, and the ratio of Pt to carbon in the anode increased. Moreover, repeated fuel starvation of the half-cell severely oxidized the carbon surface due to the high induced potential (>1.5 VRHE). The cyclic voltammogram of the anode in the half-cell experiments indicated that the characteristic feature of the oxidized carbon surface was similar to that of the anode in the single cell under anode flooding conditions during the long-term experiment. Therefore, repeated fuel starvation by anode flooding caused severe carbon corrosion in the anode because the electrode potential locally increased to >1.0 VRHE. Consequently, the density of the tri-phase boundary decreased due to the corrosion of carbons supporting the Pt nanoparticles in the anode.

  4. 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.

  5. 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...... 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 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 and integration of such a system, FURIM is expected to sufficiently promote the commercialisation of the fuel cell technology...

  6. 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...

  7. Improvement of water management in polymer electrolyte membrane fuel cell thanks to cathode cracks

    Energy Technology Data Exchange (ETDEWEB)

    Karst, Nicolas; Bouillon, Pierre [STMicroelectronics, Indre et Loire, 16 rue Pierre et Marie Curie, BP 7155, 37071 Tours Cedex 2 (France); Faucheux, Vincent; Martinent, Audrey; Simonato, Jean-Pierre [Commissariat a l' Energie Atomique (CEA) LITEN-DTNM, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France)

    2010-08-15

    The role of cathodic structure on water management was investigated for planar micro-air-breathing polymer electrolyte membrane fuel cells (PEMFCs). The electrical results demonstrate the possibility to decrease, with the same structure, both cell drying and cell flooding according to the environmental and operation conditions. Thanks to a simultaneous study of internal resistance and scanning electronic microscope (SEM) images, we demonstrate the advantageous influence of the presence of crack in cathodic catalytic layer on water management. On the one hand, the gold layer used as cathodic current collector is in contact with the electrolyte in the cracked zones which allows water maintenance within the electrolyte. It allows to decrease the cell drying and thus strongly increase the electrical performances. For cells operated in a 10% relative humidity atmosphere at 30 C and at a potential of 0.5 V, the current density increases from 28 mA cm{sup -2} to 188 mA cm{sup -2} (+570%) for the cell with a cathodic cracked network. On the other hand, the reduction in oxygen barrier diffusion due to the cathodic cracks allows to improve oxygen diffusion. In flooding state, the current densities were higher for a cell with a cracked network. For cells operating in a 70% relative humidity atmosphere at 30 C and at a potential of 0.2 V, a current density increase from 394 mA cm{sup -2} to 456 mA cm{sup -2} (16%) was noted for the cell with a cathodic cracked network. Microscopic observations allowed us to visualize water droplets growth mechanism in cathodic cracks. It was observed that the water comes out of the crack sides and partially saturates the cracks before emerging on cathodic collector. These results demonstrate that cathode structuration is a key parameter that plays a major role in the water management of PEMFCs. (author)

  8. Implications of polymer electrolyte fuel cell exposure to synchrotron radiation on gas diffusion layer water distribution

    Science.gov (United States)

    Eller, Jens; Roth, Jörg; Marone, Federica; Stampanoni, Marco; Wokaun, Alexander; Büchi, Felix N.

    2014-01-01

    Synchrotron radiation (SR) based imaging of polymer electrolyte fuel cells (PEFC), both radiography and tomography, is an attractive tool for the visualization of water in the gas diffusion layer as it provides temporal and spatial resolutions one order of magnitude superior to neutron imaging. Here we report on the degradation of cell performance and changes in GDL water saturation after SR irradiation of about 43% of a cell's active area. Fast X-ray tomographic microscopy (XTM) scans of 11 s duration are used to compare the GDL saturation before and after a 5 min irradiation period of the imaged section. The cell voltage and the water saturation decreased clearly during and after the exposure. Estimates of the current density of the SR exposed and non exposed cell domains underline the effect of irradiation.

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

    International Nuclear Information System (INIS)

    Bernardi, D.M.; Verbrugge, M.W.

    1992-01-01

    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

  10. Investigation of an alkaline direct ethanol fuel cell with non Pt-catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Beyer, M.; Guelzow, E.; Uhm, S. [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Stuttgart (Germany). Inst. fuer Technische Thermodynamik

    2010-07-01

    This paper focuses on the characterisation of an alkaline direct ethanol fuel cell (ADEFC). Ethanol and for comparison also methanol was fed to the anode in a caustic potash solution at different concentrations and temperatures. An anion exchange membrane (Tokuyama) sandwiched between two Hypermec electrodes (Acta SpA.) was investigated in a single cell. Current-voltage-measurements (U(I) characteristics), short term operation under load, electrochemical impedance spectroscopy (EIS) and pH recording were carried out to characterize fuel cell performance. The long term objective is to investigate the mechanism of ethanol electro oxidation reaction (EOR). 18 mW/cm{sup 2} was reached at room temperature with a technically oriented 50 cm{sup 2} cell with ethanol. However, poor long term stability under load of the fuel cell is observed. Furthermore in the U(I) characteristics a negative hysteresis is present in the forward and backward scan at room temperature which indicates poisoning intermediates of electrode reactions. A pH decline appears during operation indicating a development of either acetic acid or acetates or acetaldehyde as main products of the ethanol oxidation, which may be responsible for rate decrease of ethanol oxidation with time. EIS measurement shows an increased membrane resistance. (orig.)

  11. Influence of humidification on deterioration of gas diffusivity in catalyst layer on polymer electrolyte fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Hiramitsu, Y.; Sato, H.; Kobayashi, K.; Hori, M. [Fuel Cell Research Center, Daido University, 10-3 Takiharu-cho, Minami-ku, Nagoya 457-8530 (Japan); Hosomi, H.; Aoki, Y.; Harada, T.; Sakiyama, Y.; Nakagawa, Y. [Toray Research Center Inc., 3-3-7 Sonoyama, Otsu, Shiga 520-8567 (Japan)

    2010-01-15

    The effect of water on polymer electrolyte fuel cell degradation was examined with humidity as a parameter. Polymer electrolyte fuel cells were subjected to long-term operation of 10 000 h to examine the relation between decline in cell voltage and degradation of the catalyst layers or gas diffusion layers. The diffusion overpotential increased during long-term operation at relatively high humidification of 81% RH, but only in the catalyst layer and not in the gas diffusion layer. At low humidification of 52% RH, the increase in diffusion overpotential was small, indicating that the increase was more likely to occur under high humidification. Post-analysis of the catalyst layer revealed that the membrane electrode assembly had increased diffusion overpotential during operation under high humidification, as a result of the sharp decline in porosity. The increase of diffusion overpotential in the catalyst layer was also investigated by the observation of the degradation due to the oxidation of the Pt-carbon supports. However, it was found that the oxidation of carbon support which had increased diffusion overpotential was small. (author)

  12. The effect of cathodic water on performance of a polymer electrolyte fuel cell

    International Nuclear Information System (INIS)

    Kulikovsky, A.A.

    2004-01-01

    A simple analytical model of water transport in the polymer electrolyte fuel cell is developed. Nonlinear membrane resistance and voltage loss due to incomplete membrane humidification are calculated. Both values depend on parameter r, the ratio of mass transport coefficients of water in the membrane and in the backing layer. Simple equation for cell performance curve, which incorporates the effect of cathodic water is constructed. Depending of the value of r, the cell may operate in one of the two regimes. When r ≥ 1, incomplete membrane humidification simply reduces cell voltage; the limiting current density is determined by oxygen transport in the backing layer (oxygen-limiting regime). If r < 1, limiting current density is determined by membrane drying (water-limiting regime). In that case there exists optimal current density, which provides minimal membrane resistance. It is shown that membrane drying may lead to parasitic 'in-plane' proton current

  13. Electrocatalysis in alkaline media: Mechanistic studies of fuel cell reactions on well-defined model catalysts

    Science.gov (United States)

    Spendelow, Jacob S.

    Scanning tunneling microscopy and electrochemical techniques have been used to study several electrocatalytic reactions occurring on Pt(111) and Pt(111)/Ru surfaces in alkaline media. The reactions chosen, CO oxidation, methanol oxidation, and oxygen reduction, are relevant to direct methanol fuel cells (DMFCs). Each is relatively slow, and therefore requires high loading of precious metal catalysts to achieve sufficient fuel cell power density. The focus of these studies has been on determining mechanisms and limiting factors in each reaction. Special attention has been given to the role of adsorbed Ru and the role of Pt defects in enhancing catalytic activity. All defects were found to be more active than terraces for CO oxidation on Pt(111) in alkaline media at DMFC-relevant potentials. Step-typed defects enhance methanol dehydrogenation, but kink-type defects are inactive for this reaction. All defects are inactive for oxygen reduction. These observations can be explained in terms of the local geometric and electronic structure at defects. Adsorbate-adsorbate repulsions, with resultant effects on activation barriers, control the rates of CO oxidation, as well as methanol oxidation. In the case of CO, coverage-dependent CO-CO repulsions and OH-OH repulsions on defects both enhance kinetics. In the case of methanol, repulsive interactions with CO decrease the rate of methanol dehydrogenation, thus giving rise to the CO poisoning effect. Ru was found to promote both methanol dehydrogenation and CO oxidation on adjacent Pt sites. Ru enhances methanol dehydrogenation through two distinct ligand effects: it increases the intrinsic dehydrogenation activity of adjacent Pt sites, and it causes CO to diffuse away from these active sites, decreasing the CO poisoning effect. A Ru ligand effect also enhances CO oxidation by weakening the Pt-CO bond. Ru supplies adsorbed OH for bifunctional CO oxidation, but since Pt defects can also supply OH in alkaline media, the Ru

  14. 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......, with demonstrated lifetimes of only a few days to weeks. In this work the methyl phosphate formation from the acid and methanol is identified and proposed to be a major mechanism for the cell degradation. Proton conductivity and fuel cell durability tests validate the mechanism at high methanol contents....

  15. Bimetallic Ag–Ni/C particles as cathode catalyst in AFCs (alkaline fuel cells)

    International Nuclear Information System (INIS)

    Song, Xingjuan; Zhang, Dongming

    2014-01-01

    AFCs (alkaline fuel cells) is one of the promising fuel cells, due to their low working temperature and less corrosive environment. However, decreasing the catalyst cost and improving its performance are still the challenges in its application. Transition metal as the catalyst for AFCs not only can reduce its cost, but also has great electro-catalytic efficiency. In this paper, Carbon supported Ag–Ni bimetallic catalysts with differential Ag/Ni atomic ratios were prepared by chemically reducing silver and nickel salts. Ag 3 Ni/C shows the relatively higher ORR (oxygen reduction reaction) activity among the differential Ag/Ni bimetallic particles. In order to improve the activity and stability, the catalysts were heat-treated at the temperature of 500 °C. The results indicate that the limiting current density has been improved greatly for Ag 3 Ni/C-500 °C, which is as high as 2.5× that of Ag/C. The microstructure investigation show that the non-equilibrium state of Ag–Ni alloy by heat treatment is confirmed by HRTEM (high-resolution transmission electron microscopy) images, and Ag(111) surfaces are decreased in XRD pattern, which results in the ORR activity improved and overpotential decreased. Heat treatment also has contributed to Ag–Ni/C electrochemistry stability in some degree. - Highlights: • Ag–Ni/C is applied as cathode catalyst for AFCs (alkaline fuel cells). • Ag 3 Ni/C-500 °C shows the best performance. • Non-equilibrium state of Ag–Ni alloy by heat treatment is observed. • The decreased Ag(111) surfaces are favor to improve the catalyst activity

  16. Carbon supported Pd-Ni and Pd-Ru-Ni nanocatalysts for the alkaline direct ethanol fuel cell (DEFC)

    CSIR Research Space (South Africa)

    Modibedi, M

    2011-09-01

    Full Text Available alkaline anion exchange membranes (AAEMs) as the electrolyte which protects the electrodes from carbonate formation. Pd has proved to be a good electrocatalyst for ethanol oxidation in alkaline medium, showing higher activity and better steady...

  17. Solid acid proton conductors: from laboratory curiosities to fuel cell electrolytes.

    Science.gov (United States)

    Haile, Sossina M; Chisholm, Calum R I; Sasaki, Kenji; Boysen, Dane A; Uda, Tetsuya

    2007-01-01

    The compound CsH2PO4 has emerged as a viable electrolyte for intermediate temperature (200-300 degrees C) fuel cells. In order to settle the question of the high temperature behavior of this material, conductivity measurements were performed by two-point AC impedance spectroscopy under humidified conditions (p[H2O] = 0.4 atm). A transition to a stable, high conductivity phase was observed at 230 degrees C, with the conductivity rising to a value of 2.2 x 10(-2) S cm(-1) at 240 degrees C and the activation energy of proton transport dropping to 0.42 eV. In the absence of active humidification, dehydration of CsH2PO4 does indeed occur, but, in contradiction to some suggestions in the literature, the dehydration process is not responsible for the high conductivity at this temperature. Electrochemical characterization by galvanostatic current interrupt (GCI) methods and three-point AC impedance spectroscopy (under uniform, humidified gases) of CsH2PO4 based fuel cells, in which a composite mixture of the electrolyte, Pt supported on carbon, Pt black and carbon black served as the electrodes, showed that the overpotential for hydrogen electrooxidation was virtually immeasurable. The overpotential for oxygen electroreduction, however, was found to be on the order of 100 mV at 100 mA cm(-2). Thus, for fuel cells in which the supported electrolyte membrane was only 25 microm in thickness and in which a peak power density of 415 mW cm(-2) was achieved, the majority of the overpotential was found to be due to the slow rate of oxygen electrocatalysis. While the much faster kinetics at the anode over those at the cathode are not surprising, the result indicates that enhancing power output beyond the present levels will require improving cathode properties rather than further lowering the electrolyte thickness. In addition to the characterization of the transport and electrochemical properties of CsH2PO4, a discussion of the entropy of the superprotonic transition and the

  18. Polymer electrolyte fuel cell performance degradation at different synchrotron beam intensities.

    Science.gov (United States)

    Eller, Jens; Büchi, Felix N

    2014-01-01

    The degradation of cell performance of polymer electrolyte fuel cells under monochromatic X-ray irradiation at 13.5 keV was studied in galvanostatic and potentiostatic operation modes in a through-plane imaging direction over a range of two orders of magnitude beam intensity at the TOMCAT beamline of the Swiss Light Source. The performance degradation was found to be a function of X-ray dose and independent of beam intensity, whereas the degradation rate correlates with beam intensity. The cell performance was more sensitive to X-ray irradiation at higher temperature and gas feed humidity. High-frequency resistance measurements and the analysis of product water allow conclusions to be drawn on the dominating degradation processes, namely change of hydrophobicity of the electrode and sulfate contamination of the electrocatalyst.

  19. Optimization of spin-coated electrodes for electrolyte-supported solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Nobrega, Shayenne Diniz da; Monteiro, Natalia Kondo; Tabuti, Francisco; Fonseca, Fabio Coral, E-mail: shaynnedn@hotmail.com, E-mail: nataliakm@usp.br, E-mail: fntabuti@ipen.br, E-mail: fabiocf@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil); Florio, Daniel Zanetti de, E-mail: daniel.florio@ufabc.edu.br [Universidade Federal do ABC (UFABC), Santo Andre, SP (Brazil)

    2017-01-15

    Electrodes for electrolyte-supported solid oxide fuel cells (SOFC’s) were fabricated by spin coating. Strontium-doped lanthanum manganite (LSM) cathode and nickel yttria-stabilized zirconia cermet anodes were synthesized and processed for enhanced deposition conditions. The influence of electrode microstructural parameters was investigated by a systematic experimental procedure aiming at optimized electrochemical performance of single cells. Polarization curves showed a strong dependence on both electrode thickness and sintering temperature. By a systematic control of such parameters, the performance of single cells was significantly enhanced due to decreasing of polarization resistance from 26 Ω cm² to 0.6 Ω cm² at 800°C. The results showed that spin-coated electrodes can be optimized for fast and cost effective fabrication of SOFCs. (author)

  20. Local impact of humidification on degradation in polymer electrolyte fuel cells

    Science.gov (United States)

    Sanchez, Daniel G.; Ruiu, Tiziana; Biswas, Indro; Schulze, Mathias; Helmly, Stefan; Friedrich, K. Andreas

    2017-06-01

    The water level in a polymer electrolyte membrane fuel cell (PEMFC) affects the durability as is seen from the degradation processes during operation a PEMFC with fully- and nonhumidified gas streams as analyzed using an in-situ segmented cell for local current density measurements during a 300 h test operating under constant conditions and using ex situ SEM/EDX and XPS post-test analysis of specific regions. The impact of the RH on spatial distribution of the degradation process results from different water distribution giving different chemical environments. Under nonhumidified gas streams, the cathode inlet region exhibits increased degradation, whereas with fully humidified gases the bottom of the cell had the higher performance losses. The degradation and the degree of reversibility produced by Pt dissolution, PTFE defluorination, and contaminants such as silicon (Si) and nickel (Ni) were locally evaluated.

  1. 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.

  2. Methods for continuous direct carbon fuel cell operation with a circulating electrolyte slurry

    Energy Technology Data Exchange (ETDEWEB)

    Harjes, Daniel I.; Dineen, Jr., D. Andrew; Guo, Liang; Calo, Joseph M.; Bloomfield, Valerie J.

    2017-02-07

    The present invention relates to methods and systems related to fuel cells, and in particular, to direct carbon fuel cells. The methods and systems relate to cleaning and removal of components utilized and produced during operation of the fuel cell, regeneration of components utilized during operation of the fuel cell, and generating power using the fuel cell.

  3. Electrolyte for phosphoric acid fuel cell. Rinsangata nenryo denchi no denkaieki

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Y.; Uede, M.; Yamaken, H. (Yamaha Motor Co. Ltd., Shizuoka (Japan))

    1991-02-14

    When the phosphoric fuel cell is used in cold districts, the electrolyte used in the cell solidifies and freezes because its freezing point is high, and the cell can not be used any more. The object of this invention is to provide a fuel cell which does not freeze even the cell is shutdown in low temperature environment by adding non-conjugating inorganic salt to strong phosphoric acid to lower the freezing point. The phosphoric acid used in accordance with this invention is desirable generally to be of 80 to 105% if calculated in terms of orthophosphoric acid to maintain the cell performance. As the negative ions constituting the non-conjugating inorganic salt, sulphate ion, carbonate ion, silicate ion, and boric acid ion are desirable. In concrete, ZnSO{sub 4}, NiSO{sub 4}, Na{sub 2}SO{sub 4}, BeSO{sub 4}, CdSO{sub 4}, CoSO{sub 4}, FeSO{sub 4}, K{sub 2}CO{sub 3}, Na{sub 2}CO{sub 3}, CaCO{sub 3}, MgCO{sub 3}, K{sub 2}SiO{sub 3}, Na{sub 2}B{sub 4}O{sub 7}, etc. can be quoted. Excessive addition of inorganic salt results rather in the precipitation of the added inorganic salt to cause freezing, and addition of 20wt% or less is desirable. 1 fig.

  4. Electrodeposited gold nanoparticles on carbon nanotube-textile: Anode material for glucose alkaline fuel cells

    KAUST Repository

    Pasta, Mauro

    2012-06-01

    In the present paper we propose a new anode material for glucose-gluconate direct oxidation fuel cells prepared by electrodepositing gold nanoparticles onto a conductive textile made by conformally coating single walled carbon nanotubes (SWNT) on a polyester textile substrate. The electrodeposition conditions were optimized in order to achieve a uniform distribution of gold nanoparticles in the 3D porous structure of the textile. On the basis of previously reported studies, the reaction conditions (pH, electrolyte composition and glucose concentration) were tuned in order to achieve the highest oxidation rate, selectively oxidizing glucose to gluconate. The electrochemical characterization was carried out by means of cyclic voltammetry. © 2012 Elsevier B.V. All rights reserved.

  5. Investigation of a polymer electrolyte membrane fuel cell catalyst layer with bidirectionally-graded composition

    Science.gov (United States)

    Cetinbas, Firat C.; Advani, Suresh G.; Prasad, Ajay K.

    2014-12-01

    The catalyst layer (CL) of the polymer electrolyte membrane (PEM) fuel cell must be modeled accurately in order to resolve the effects of complex interactions between charge and mass transport on the fuel cell's electrochemical reactions. In previous work, we developed an agglomerate model [1] which correctly accounts for variations in the agglomerate surface area as the CL constituents are varied to provide a better estimate of diffusion losses. Here, this improved agglomerate model is employed to investigate a PEM fuel cell catalyst layer with a functionally-graded composition. We present results for varying catalyst and ionomer loadings in both the through-thickness and in-plane directions. In agreement with experimental observations, we find that a higher catalyst and/or ionomer loading at the membrane/CL interface improves performance especially in the ohmic loss regime. Similarly, improved performance is observed for higher catalyst and/or ionomer loadings under the channel in the mass transport loss regime. In addition, we investigated bidirectionally graded CLs for the first time. It is observed that higher performance can be obtained with bidirectionally graded CLs in both ohmic and mass transport loss regimes.

  6. Operando 3D Visualization of Migration and Degradation of a Platinum Cathode Catalyst in a Polymer Electrolyte Fuel Cell

    OpenAIRE

    Hirosuke, Matsui; Nozomu, Ishiguro; Tomoya, Uruga; Oki, Sekizawa; Kotaro, Higashi; Naoyuki, Maejima; Mizuki, Tada

    2017-01-01

    The three-dimensional (3D) distribution and oxidation state of a Pt cathode catalyst in a practical membrane electrode assembly (MEA) were visualized in a practical polymer electrolyte fuel cell (PEFC) under fuel-cell operating conditions. Operando 3D computed-tomography imaging with X-ray absorption near edge structure (XANES) spectroscopy (CT-XANES) clearly revealed the heterogeneous migration and degradation of Pt cathode catalyst in an MEA during accelerated degradation test (ADT) of PEFC...

  7. Heat and fuel coupled operation of a high temperature polymer electrolyte fuel cell with a heat exchanger methanol steam reformer

    Science.gov (United States)

    Schuller, G.; Vázquez, F. Vidal; Waiblinger, W.; Auvinen, S.; Ribeirinha, P.

    2017-04-01

    In this work a methanol steam reforming (MSR) reactor has been operated thermally coupled to a high temperature polymer electrolyte fuel cell stack (HT-PEMFC) utilizing its waste heat. The operating temperature of the coupled system was 180 °C which is significantly lower than the conventional operating temperature of the MSR process which is around 250 °C. A newly designed heat exchanger reformer has been developed by VTT (Technical Research Center of Finland LTD) and was equipped with commercially available CuO/ZnO/Al2O3 (BASF RP-60) catalyst. The liquid cooled, 165 cm2, 12-cell stack used for the measurements was supplied by Serenergy A/S. The off-heat from the electrochemical fuel cell reaction was transferred to the reforming reactor using triethylene glycol (TEG) as heat transfer fluid. The system was operated up to 0.4 A cm-2 generating an electrical power output of 427 Wel. A total stack waste heat utilization of 86.4% was achieved. It has been shown that it is possible to transfer sufficient heat from the fuel cell stack to the liquid circuit in order to provide the needed amount for vaporizing and reforming of the methanol-water-mixture. Furthermore a set of recommendations is given for future system design considerations.

  8. Durability and degradation analysis of hydrocarbon ionomer membranes in polymer electrolyte fuel cells accelerated stress evaluation

    Science.gov (United States)

    Shimizu, Ryo; Tsuji, Junichi; Sato, Nobuyuki; Takano, Jun; Itami, Shunsuke; Kusakabe, Masato; Miyatake, Kenji; Iiyama, Akihiro; Uchida, Makoto

    2017-11-01

    The chemical durabilities of two proton-conducting hydrocarbon polymer electrolyte membranes, sulfonated benzophenone poly(arylene ether ketone) (SPK) semiblock copolymer and sulfonated phenylene poly(arylene ether ketone) (SPP) semiblock copolymer are evaluated under accelerated open circuit voltage (OCV) conditions in a polymer electrolyte fuel cell (PEFC). Post-test characterization of the membrane electrodes assemblies (MEAs) is carried out via gel permeation chromatography (GPC) and nuclear magnetic resonance (NMR) spectroscopy. These results are compared with those of the initial MEAs. The SPP cell shows the highest OCV at 1000 h, and, in the post-test analysis, the SPP membrane retains up to 80% of the original molecular weight, based on the GPC results, and 90% of the hydrophilic structure, based on the NMR results. The hydrophilic structure of the SPP membrane is more stable after the durability evaluation than that of the SPK. From these results, the SPP membrane, with its simple hydrophilic structure, which does not include ketone groups, is seen to be significantly more resistant to radical attack. This structure leads to high chemical durability and thus impedes the chemical decomposition of the membrane.

  9. A graphite-coated carbon fiber epoxy composite bipolar plate for polymer electrolyte membrane fuel cell

    Science.gov (United States)

    Yu, Ha Na; Lim, Jun Woo; Suh, Jung Do; Lee, Dai Gil

    A PEMFC (polymer electrolyte membrane fuel cell or proton exchange membrane fuel cell) stack is composed of GDLs (gas diffusion layers), MEAs (membrane electrode assemblies), and bipolar plates. One of the important functions of bipolar plates is to collect and conduct the current from cell to cell, which requires low electrical bulk and interfacial resistances. For a carbon fiber epoxy composite bipolar plate, the interfacial resistance is usually much larger than the bulk resistance due to the resin-rich layer on the composite surface. In this study, a thin graphite layer is coated on the carbon/epoxy composite bipolar plate to decrease the interfacial contact resistance between the bipolar plate and the GDL. The total electrical resistance in the through-thickness direction of the bipolar plate is measured with respect to the thickness of the graphite coating layer, and the ratio of the bulk resistance to the interfacial contact resistance is estimated using the measured data. From the experiment, it is found that the graphite coating on the carbon/epoxy composite bipolar plate has 10% and 4% of the total electrical and interfacial contact resistances of the conventional carbon/epoxy composite bipolar plate, respectively, when the graphite coating thickness is 50 μm.

  10. 3-Dimensional Computational Fluid Dynamics Modeling of Solid Oxide Fuel Cell Using Different Fuels

    Science.gov (United States)

    2011-01-01

    major types of fuel cells in practice are listed below: Polymer Electrolyte Membrane Fuel Cell ( PEMFC ) Alkaline Fuel cell (AFC) Phosphoric Acid...Material Operating Temperature (oC) Efficiency (%) PEMFC H2, Methanol, Formic Acid Hydrated Organic Polymer < 90 40-50 AFC Pure H2 Aqueous

  11. Novel fluoropolymer anion exchange membranes for alkaline direct methanol fuel cells.

    Science.gov (United States)

    Zhang, Yanmei; Fang, Jun; Wu, Yongbin; Xu, Hankun; Chi, Xianjun; Li, Wei; Yang, Yixu; Yan, Ge; Zhuang, Yongze

    2012-09-01

    A series of novel fluoropolymer anion exchange membranes based on the copolymer of vinylbenzyl chloride, butyl methacrylate, and hexafluorobutyl methacrylate has been prepared. Fourier transform infrared (FT-IR) spectroscopy and elemental analysis techniques are used to study the chemical structure and chemical composition of the membranes. The water uptake, ion-exchange capacity (IEC), conductivity, methanol permeability, and chemical stability of the membranes are also determined. The membranes exhibit high anionic conductivity in deionized water at 65 °C ranging from 3.86×10(-2) S cm(-1) to 4.36×10(-2) S cm(-1). The methanol permeability coefficients of the membranes are in the range of 4.21-5.80×10(-8) cm(2) s(-1) at 65 °C. The novel membranes also show good chemical and thermal stability. An open-circuit voltage of 0.7 V and a maximum power density of 53.2 mW cm(-2) of alkaline direct methanol fuel cell (ADMFC) with the membrane C, 1 M methanol, 1 M NaOH, and humidified oxygen are achieved at 65 °C. Therefore, these membranes have great potential for applications in fuel cell systems. Copyright © 2012 Elsevier Inc. All rights reserved.

  12. Preparation, characterisation and application of Pd/C nanocatalyst in passive alkaline direct ethanol fuel cells (ADEFC)

    CSIR Research Space (South Africa)

    Modibedi, RM

    2015-10-01

    Full Text Available This work describes the use of Pd nanocatalyst on Vulcan XC-72 (at a very low loading, 8 wt % Pd) in passive alkaline direct ethanol fuel cell (ADEFC). The average Pd particle size obtained with TEM was 3.5 ± 0.5 nm. The XRD results of the prepared...

  13. Nanostructured Gd-CeO2 electrolyte for solid oxide fuel cell by aqueous tape casting

    Science.gov (United States)

    Akbari-Fakhrabadi, A.; Mangalaraja, R. V.; Sanhueza, Felipe A.; Avila, Ricardo E.; Ananthakumar, S.; Chan, S. H.

    2012-11-01

    Gadolinia-doped ceria (Ce0.9Gd0.1O1.95, GDC) electrolyte was fabricated by aqueous-based tape casting method for solid oxide fuel cells (SOFCs). The ceramic powder prepared by combustion synthesis was used with poly acrylic acid (PAA), poly vinyl alcohol (PVA), poly ethylene glycol (PEG), Octanol, 2,4,7,9-tetramethyl-5-decyne-4,7-diol ethoxylate and double distilled water as dispersant, binder, plasticizer, defoamer, surfactant and solvent respectively, to prepare stable GDC slurry. The conditions for preparing stable GDC slurries were studied and optimized by sedimentation, zeta potential and viscosity measurements. Green tapes with smooth surface, flexibility, thickness in the range of 0.35-0.4 mm and 45% relative green density were prepared. Conventional and flash sintering techniques were used and compared for densification which demonstrated the possibility of surpassing sintering at high temperatures and retarding related grain growth.

  14. 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.

  15. Engineered Graphene Materials: Synthesis and Applications for Polymer Electrolyte Membrane Fuel Cells.

    Science.gov (United States)

    He, Daping; Tang, Haolin; Kou, Zongkui; Pan, Mu; Sun, Xueliang; Zhang, Jiujun; Mu, Shichun

    2017-05-01

    Engineered graphene materials (EGMs) with unique structures and properties have been incorporated into various components of polymer electrolyte membrane fuel cells (PEMFCs) such as electrode, membrane, and bipolar plates to achieve enhanced performances in terms of electrical conductivity, mechanical durability, corrosion resistance, and electrochemical surface area. This research news article provides an overview of the recent development in EGMs and EGM-based PEMFCs with a focus on the effects of EGMs on PEMFC performance when they are incorporated into different components of PEMFCs. The challenges of EGMs for practical PEMFC applications in terms of production scale, stability, conductivity, and coupling capability with other materials are also discussed and the corresponding measures and future research trends to overcome such challenges are proposed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Microstructural densification and electrical performance of yttria stabilized zirconia SOCF (Solid Oxide Fuel Cell) electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Furtado, J.G. de M., E-mail: furtado@cepel.b [Centro de Pesquisas de Energia Eletrica (ELETROBRAS/CEPEL), Rio de Janeiro, RJ (Brazil); Silva, C.A. da; Miranda, P.E.V. de [Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Metalurgica e de Materiais

    2010-07-01

    The understanding of the mechanisms associated with densification and sintering of Yttria stabilized zirconia (YSZ), a main solid oxide fuel cell electrolyte, enables the improvement of its microstructure. The present work that has the objective to study the sintering and densification processes of polycrystalline nanostructured 8% mol YSZ (8YSZ), correlating the microstructural development with the electrical performance of the material. The sintering behaviors of nanocrystalline 8YSZ powders obtained by two different chemical synthesis techniques (glycine-nitrate combustion process and Pechini method) were studied based on sintering dilatometer method. X-ray diffraction and scanning electron microscopy were used in the microstructural characterization. Full-densified 8YSZ (98.8%) were obtained and it was found that the samples obtained by the Pechini's method showed a higher densification degree in the final stage of sintering and resulted in ceramics with higher final relative density and better electrical behavior. (author)

  17. Small-angle neutron scattering investigation of Pt-loaded electrodes for polymer electrolyte fuel cells

    International Nuclear Information System (INIS)

    Coppola, R.; Giorgi, L.; Lapp, A.

    1999-01-01

    Complete text of publication follows. Pt-loaded carbon catalysts are being developed for polymer electrolyte fuel cell technology. They are prepared by depositing, with different techniques, an electrocatalytic layer containing dispersed Pt clusters on a composite carbon substrate. The performance and the lifetime of these catalysts are strongly correlated to the deposition technique, to the Pt content and to the size distribution function of the Pt clusters. Small-angle neutron scattering (SANS) measurements have been carried out on catalysts with relatively high Pt deposited content (.5 mg cm -2 ). A Pt-free C-paper support (identical to the one used for the platinized samples) has been used as a reference to obtain the SANS signal arising from the Pt clusters. Their size distribution function has been determined and compared with the results of transmission electron microscopy (TEM) observations. (author)

  18. Influence of Ionomer/Carbon Ratio on the Performance of a Polymer Electrolyte Fuel Cell

    Directory of Open Access Journals (Sweden)

    Toshihiro Ando

    2012-11-01

    Full Text Available We have used fibrous carbon materials as polymer electrolyte fuel cell (PEFC electrodes. We have examined the influence of the ionomer/carbon ratio on the performance of the PEFCs. The Marimo carbon is a kind of carbon with a spherical shape, and consists of carbon nanofilaments. Fibrous carbon materials have large specific surface areas without fine pores. The reactant gases and generated water can easily diffuse among the nanofilaments. The ionomer plays two roles; one is a proton transfer activity, and the other is binding the catalyst electrodes. An excess ionomer interferes with the diffusion of gases. The ionomer/carbon ratio should affect the performance of the PEFC, especially at a high current density.

  19. Niobium phosphates as an intermediate temperature proton conducting electrolyte for fuel cells

    DEFF Research Database (Denmark)

    Huang, Yunjie; Li, Qingfeng; Jensen, Annemette Hindhede

    2012-01-01

    A new proton conductor based on niobium phosphates was synthesized using niobium pentoxide and phosphoric acid as precursors. The existence of hydroxyl groups in the phosphates was confirmed and found to be preserved after heat treatment at 500 °C or higher, contributing to an anhydrous proton co...... are of high interest as potential proton conducting electrolytes for fuel cells operational in an intermediate temperature range....... conductivity of 1.6 × 10−2 S cm−1 at 250 °C. The conductivity increased with water content in the atmosphere and reached 5.8 × 10−2 S cm−1 under pure water vapour at the same temperature. The conductivity showed good stability in the low water partial pressure range of up to 0.05 atm. The metal phosphates...

  20. Carbon nanostructures as catalyst support for polymer electrolyte membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Natarajan, S.K.; Hamelin, J. [Quebec Univ., Trois Rivieres, PQ (Canada). Inst. de recherche sur l' hydrogene

    2008-07-01

    This paper reported on a study that investigated potential alternatives to Vulcan XC-72 as a catalyst supports for polymer electrolyte membrane fuel cells (PEMFCs). These included carbon nanostructures (CNS) prepared by high energy ball milling of graphite and transition metal catalysts, followed by heat treatment. Among the key factors discussed were the graphitic content, high surface area, microporous structure, good electrical conductivity and the ability of the material to attach functional groups. Some graphic results supporting the usage of CNS as catalyst support for PEMFCs were presented. Upon chemical oxidation, surface functional groups such as carbonyl, carboxyl, and hydroxyl were populated on the surface of CNS. Nanosized platinum particles with particle size distribution between 3 nm and 5 nm were reduced on the functionalized sites of CNS in a colloidal medium. The paper also presented cyclic voltammograms, XPS, HRTEM and PSD results. 3 refs.

  1. 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)

  2. Alkaline RFC Space Station prototype - 'Next step Space Station'. [Regenerative Fuel Cells

    Science.gov (United States)

    Hackler, I. M.

    1986-01-01

    The regenerative fuel cell, a candidate technology for the Space Station's energy storage system, is described. An advanced development program was initiated to design, manufacture, and integrate a regenerative fuel cell Space Station prototype (RFC SSP). The RFC SSP incorporates long-life fuel cell technology, increased cell area for the fuel cells, and high voltage cell stacks for both units. The RFC SSP's potential for integration with the Space Station's life support and propulsion systems is discussed.

  3. ELECTROOXIDATION OF COCONUT OIL IN ALKALINE ELECTROLYTE

    Directory of Open Access Journals (Sweden)

    Paweł Piotr Włodarczyk

    2017-09-01

    Full Text Available Providing more and more energy is an essential task of today's energetic industry. In the last few years, addition to traditional methods of energy production, alternative energy sources have been fast developing. One of the devices that can use these sources is fuel cell. The fuel cells can be a power source of future mainly due to their high efficiency, low influence on environment and possibility of powering with different fuels. Most often fuel cells are powered by hydrogen. However, problems with the problems with its cheap production and storage are the reason for the search of new fuels for fuel cells. But it must be a fuel that will provide zero or low emission level. One of these fuels can be vegetable oil. The paper presents measurements of electrooxidation of coconut oil emulsion on a smooth platinum electrode in an aqueous solution of KOH. Electrochemical measurements were performed in a glass cell with AMEL System 5000 potentiostat. The obtained maximum current density is equal 25 mA/cm2. So, a fundamental possibility of using the coconut oil as fuel for fuel cell. But is necessary to keep the temperature of process above 303K.

  4. A polymer electrolyte membrane for high temperature fuel cells to fit vehicle applications

    International Nuclear Information System (INIS)

    Li Mingqiang; Scott, Keith

    2010-01-01

    Poly(tetrafluoroethylene) PTFE/PBI composite membranes doped with H 3 PO 4 were fabricated to improve the performance of high temperature polymer electrolyte membrane fuel cells (HT-PEMFC). The composite membranes were fabricated by immobilising polybenzimidazole (PBI) solution into a hydrophobic porous PTFE membrane. The mechanical strength of the membrane was good exhibiting a maximum load of 35.19 MPa. After doping with the phosphoric acid, the composite membrane had a larger proton conductivity than that of PBI doped with phosphoric acid. The PTFE/PBI membrane conductivity was greater than 0.3 S cm -1 at a relative humidity 8.4% and temperature of 180 deg. C with a 300% H 3 PO 4 doping level. Use of the membrane in a fuel cell with oxygen, at 1 bar overpressure gave a peak power density of 1.2 W cm -2 at cell voltages >0.4 V and current densities of 3.0 A cm -2 . The PTFE/PBI/H 3 PO 4 composite membrane did not exhibit significant degradation after 50 h of intermittent operation at 150 deg. C. These results indicate that the composite membrane is a promising material for vehicles driven by high temperature PEMFCs.

  5. 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).

  6. Water transport in the gas diffusion layer of a polymer electrolyte fuel cell : Dynamic Pore-Network Modeling

    NARCIS (Netherlands)

    Qin, C.

    2015-01-01

    The pore-scale modeling is a powerful tool for increasing our understanding of water transport in the fibrous gas diffusion layer (GDL) of a polymer electrolyte fuel cell (PEFC). In this work, a new dynamic pore-network model for air-water flow in the GDL is developed. It incorporates water vapor

  7. 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

    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...

  8. 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 establ...

  9. First Principles and Genetic Algorithm Studies of Lanthanide Metal Oxides for Optimal Fuel Cell Electrolyte Design

    Science.gov (United States)

    Ismail, Arif

    As the demand for clean and renewable energy sources continues to grow, much attention has been given to solid oxide fuel cells (SOFCs) due to their efficiency and low operating temperature. However, the components of SOFCs must still be improved before commercialization can be reached. Of particular interest is the solid electrolyte, which conducts oxygen ions from the cathode to the anode. Samarium-doped ceria (SDC) is the electrolyte of choice in most SOFCs today, due mostly to its high ionic conductivity at low temperatures. However, the underlying principles that contribute to high ionic conductivity in doped ceria remain unknown, and so it is difficult to improve upon the design of SOFCs. This thesis focuses on identifying the atomistic interactions in SDC which contribute to its favourable performance in the fuel cell. Unfortunately, information as basic as the structure of SDC has not yet been found due to the difficulty in experimentally characterizing and computationally modelling the system. For instance, to evaluate 10.3% SDC, which is close to the 11.1% concentration used in fuel cells, one must investigate 194 trillion configurations, due to the numerous ways of arranging the Sm ions and oxygen vacancies in the simulation cell. As an exhaustive search method is clearly unfeasible, we develop a genetic algorithm (GA) to search the vast potential energy surface for the low-energy configurations, which will be most prevalent in the real material. With the GA, we investigate the structure of SDC for the first time at the DFT+U level of theory. Importantly, we find key differences in our results from prior calculations of this system which used less accurate methods, which demonstrate the importance of accurately modelling the system. Overall, our simulation results of the structure of SDC agree with experimental measurements. We identify the structural significance of defects in the doped ceria lattice which contribute to oxygen ion conductivity. Thus

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

    DEFF Research Database (Denmark)

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

    found that crosslinking by divinylbenzene clear­ly improves the chemical stability of both sulfonated styrene- and methylstyrene/t-butylstyrene-grafted ETFE membranes. How­ever, the crosslinking reduces the proton conductivity due to decreased water uptake, thus downgrading the membranes' elec­tro­ly­tic......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...... that the material consists of hydrophilic and hydrophobic domains. This structure gives hy­drated Nafion® very high proton conductivity as well as great stability.[i]           However, the poly(perfluorosulfonic acid) membranes are very expensive materials, and their high water uptake, significant methanol...

  11. A Rechargeable Li-Air Fuel Cell Battery Based on Garnet Solid Electrolytes

    Science.gov (United States)

    Sun, Jiyang; Zhao, Ning; Li, Yiqiu; Guo, Xiangxin; Feng, Xuefei; Liu, Xiaosong; Liu, Zhi; Cui, Guanglei; Zheng, Hao; Gu, Lin; Li, Hong

    2017-01-01

    Non-aqueous Li-air batteries have been intensively studied in the past few years for their theoretically super-high energy density. However, they cannot operate properly in real air because they contain highly unstable and volatile electrolytes. Here, we report the fabrication of solid-state Li-air batteries using garnet (i.e., Li6.4La3Zr1.4Ta0.6O12, LLZTO) ceramic disks with high density and ionic conductivity as the electrolytes and composite cathodes consisting of garnet powder, Li salts (LiTFSI) and active carbon. These batteries run in real air based on the formation and decomposition at least partially of Li2CO3. Batteries with LiTFSI mixed with polyimide (PI:LiTFSI) as a binder show rechargeability at 200 °C with a specific capacity of 2184 mAh g−1carbon at 20 μA cm−2. Replacement of PI:LiTFSI with LiTFSI dissolved in polypropylene carbonate (PPC:LiTFSI) reduces interfacial resistance, and the resulting batteries show a greatly increased discharge capacity of approximately 20300 mAh g−1carbon and cycle 50 times while maintaining a cutoff capacity of 1000 mAh g−1carbon at 20 μA cm−2 and 80 °C. These results demonstrate that the use of LLZTO ceramic electrolytes enables operation of the Li-air battery in real air at medium temperatures, leading to a novel type of Li-air fuel cell battery for energy storage. PMID:28117359

  12. Novel polybenzimidazole derivatives for high temperature polymer electrolyte membrane fuel cell applications

    Science.gov (United States)

    Xiao, Lixiang

    Recent advances have made polymer electrolyte membrane fuel cells (PEMFCs) a leading alternative to internal combustion engines for both stationary and transportation applications. In particular, high temperature polymer electrolyte membranes operational above 120°C without humidification offer many advantages including fast electrode kinetics, high tolerance to fuel impurities and simple thermal and water management systems. A series of polybenzimidazole (PBI) derivatives including pyridine-based PBI (PPBI) and sulfonated PBI (SPBI) homopolymers and copolymers have been synthesized using polyphosphoric acid (PPA) as both solvent and polycondensation agent. High molecular weight PBI derivative polymers were obtained with well controlled backbone structures in terms of pyridine ring content, polymer backbone rigidity and degree of sulfonation. A novel process, termed the PPA process, has been developed to prepare phosphoric acid (PA) doped PBI membranes by direct-casting of the PPA polymerization solution without isolation or re-dissolution of the polymers. The subsequent hydrolysis of PPA to PA by moisture absorbed from the atmosphere usually induced a transition from the solution-like state to a gel-like state and produced PA doped PBI membranes with a desirable suite of physiochemical properties characterized by the PA doping levels, mechanical properties and proton conductivities. The effects of the polymer backbone structure on the polymer characteristics and membrane properties, i.e., the structure-property relationships of the PBI derivative polymers have been studied. The incorporation of additional basic nitrogen containing pyridine rings and sulfonic acid groups enhanced the polymer solubility in acid and dipolar solvents while retaining the inherently high thermal stability of the PBI heteroaromatic backbone. In particular, the degradation of the SPBI polymers with reasonable high molecular weights commenced above 450°C, notably higher than other

  13. Effect of process parameters on the dynamic behavior of polymer electrolyte membrane fuel cells for electric vehicle applications

    Directory of Open Access Journals (Sweden)

    A.A. Abd El Monem

    2014-03-01

    Full Text Available This paper presents a dynamic mathematical model for Polymer Electrolyte Membrane “PEM” fuel cell systems to be used for electric vehicle applications. The performance of the fuel cell, depending on the developed model and taking the double layer charging effect into account, is investigated with different process parameters to evaluate their effect on the unit behavior. Thus, it will be easy to develop suitable controllers to regulate the unit operation, which encourages the use of fuel cells especially with electric vehicles applications. The steady-state performance of the fuel cell is verified using a comparison with datasheet data and curves provided by the manufacturer. The results and conclusions introduced in this paper provide a base for further investigation of fuel cells-driven dc motors for electric vehicle.

  14. Introduction of functionalizable groups via radiation grafting into polymer electrolyte membranes for fuel cells

    International Nuclear Information System (INIS)

    Buchmueller, Y.; Scherer, G.G.; Wokaun, A.; Gubler, L.

    2011-01-01

    Complete text of publication follows. Our work is focused on the introduction of functionalizable groups, so called linkers, to polymer electrolyte membranes. The aim is to attach antioxidant groups to the linkers to enhance the durability of the proton conducting membrane in a fuel cell. The synthetic route we chose is radiation cografting of functionalizable monomers and precursor monomers of a protogenic group into ETFE base film (thickness 25 μm) with subsequent amination. Typically, we performed cografting of styrene with different linkers, such as acryloyl chloride, vinylbenzyl chloride, and glycidyl methacrylate. Styrene is readily sulfonated to introduce proton conductivity. The cografting behavior of the linkers and styrene was investigated to target the desired molar fraction of the monomers in the grafted polymer. All films were characterized by Fourier transform infrared (FTIR) spectroscopy and elemental analysis. Using these data the graft polymerization kinetics of these systems have been determined. The cografted films were first functionalized with amines, such as thyramine and dopamine, and then sulfonated or vice-versa, depending on the stability of the compounds in acidic environment. The synthesized membranes were characterized for conductivity and ion exchange capacity (IEC). Promising membranes were tested in a fuel cell.

  15. Performance analysis of polymer electrolyte membranes for direct methanol fuel cells

    Science.gov (United States)

    Lufrano, F.; Baglio, V.; Staiti, P.; Antonucci, V.; Arico', A. S.

    2013-12-01

    The status of research and development of polymer electrolyte membranes (PEMs) for direct methanol fuel cells (DMFCs) is described. Perfluorosulfonic acid membranes, e.g. Nafion, are widely used in fuel cell technology; but, despite their success, they show some drawbacks such as high cost, limited operating temperature range and high methanol crossover. These limit their widespread commercial application in DMFCs. Such disadvantages are inspiring worldwide research activities for developing new PEM materials based on non-perfluorinated polymers as alternative to Nafion for DMFCs. A review of membrane properties is carried out on the basis of thermal stability, methanol crossover and proton conductivity. The analysis of DMFC performance covers perfluorosulfonic acid membranes (PFSA), sulfonated aromatic polymers (SAPs) and composite membranes. PFSA membranes are suitable materials in terms of power density, SAPs are more advantageous regarding the low methanol permeability and cost, whereas composite membranes are more appropriate for operation above 100 °C. DMFC power density values reported in literature show that, although there are remarkable research efforts on this subject, the achieved results are not yet satisfying. Further work is especially necessary on non-perfluorinated polymers to improve performance and durability for an effective application in practical DMFC devices.

  16. Polybenzimidazole/Mxene composite membranes for intermediate temperature polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Fei, Mingming; Lin, Ruizhi; Deng, Yuming; Xian, Hongxi; Bian, Renji; Zhang, Xiaole; Cheng, Jigui; Xu, Chenxi; Cai, Dongyu

    2018-01-01

    This report demonstrated the first study on the use of a new 2D nanomaterial (Mxene) for enhancing membrane performance of intermediate temperature (>100 °C) polymer electrolyte membrane fuel cells (ITPEMFCs). In this study, a typical Ti3C2T x -MXene was synthesized and incorporated into polybenzimidazole (PBI)-based membranes by using a solution blending method. The composite membrane with 3 wt% Ti3C2T x -MXene showed the proton conductivity more than 2 times higher than that of pristine PBI membrane at the temperature range of 100 °C-170 °C, and led to substantial increase in maximum power density of fuel cells by ˜30% tested at 150 °C. The addition of Ti3C2T x -MXene also improved the mechanical properties and thermal stability of PBI membranes. At 3 wt% Ti3C2T x -MXene, the elongation at break of phosphoric acid doped PBI remained unaffected at 150 °C, and the tensile strength and Young’s modulus was increased by ˜150% and ˜160%, respectively. This study pointed out promising application of MXene in ITPEMFCs.

  17. 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

  18. 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

    2012-12-18

    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.

  19. 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

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

    Science.gov (United States)

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

    2017-04-01

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

  1. 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

    by sulfonation. The sulfonated hydrocarbons and their inorganic composites are potentially promising for high-temperature operation. High conductivities have been obtained at temperatures up to 180 °C. Acid-base complex membranes constitute another class of electrolyte membranes. A high-temperature PEMFC based......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...

  2. Nafion/silane nanocomposite membranes for high temperature polymer electrolyte membrane fuel cell.

    Science.gov (United States)

    Ghi, Lee Jin; Park, Na Ri; Kim, Moon Sung; Rhee, Hee Woo

    2011-07-01

    The polymer electrolyte membrane fuel cell (PEMFC) has been studied actively for both potable and stationary applications because it can offer high power density and be used only hydrogen and oxygen as environment-friendly fuels. Nafion which is widely used has mechanical and chemical stabilities as well as high conductivity. However, there is a drawback that it can be useless at high temperatures (> or = 90 degrees C) because proton conducting mechanism cannot work above 100 degrees C due to dehydration of membrane. Therefore, PEMFC should be operated for long-term at high temperatures continuously. In this study, we developed nanocomposite membrane using stable properties of Nafion and phosphonic acid groups which made proton conducting mechanism without water. 3-Aminopropyl triethoxysilane (APTES) was used to replace sulfonic acid groups of Nafion and then its aminopropyl group was chemically modified to phosphonic acid groups. The nanocomposite membrane showed very high conductivity (approximately 0.02 S/cm at 110 degrees C, <30% RH).

  3. 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.

  4. Current collector design for closed-plenum polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Daniels, F. A.; Attingre, C.; Kucernak, A. R.; Brett, D. J. L.

    2014-03-01

    This work presents a non-isothermal, single-phase, three-dimensional model of the effects of current collector geometry in a 5 cm2 closed-plenum polymer electrolyte membrane (PEM) fuel cell constructed using printed circuit boards (PCBs). Two geometries were considered in this study: parallel slot and circular hole designs. A computational fluid dynamics (CFD) package was used to account for species, momentum, charge and membrane water distribution within the cell for each design. The model shows that the cell can reach high current densities in the range of 0.8 A cm-2-1.2 A cm-2 at 0.45 V for both designs. The results indicate that the transport phenomena are significantly governed by the flow field plate design. A sensitivity analysis on the channel opening ratio shows that the parallel slot design with a 50% opening ratio shows the most promising performance due to better species, heat and charge distribution. Modelling and experimental analysis confirm that flooding inhibits performance, but the risk can be minimised by reducing the relative humidity of the cathode feed to 50%. Moreover, overheating is a potential problem due to the insulating effect of the PCB base layer and as such strategies should be implemented to combat its adverse effects.

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

    International Nuclear Information System (INIS)

    Garcia, Rafael Henrique Lazzari

    2007-01-01

    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

  6. 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.

  7. Fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Enomoto, Hirofumi.

    1989-05-22

    This invention aims to maintain a long-term operation with stable cell output characteristics by uniformly supplying an electrolyte from the reserver to the matrix layer over the entire matrix layer, and further to prevent the excessive wetting of the catalyst layer by smoothly absorbing the volume change of the electrolyte, caused by the repeated stop/start-up of the fuel cell, within the reserver system. For this purpose, in this invention, an electrolyte transport layer, which connects with an electrolyte reservor formed at the electrode end, is partly formed between the electrode material and the catalyst layer; a catalyst layer, which faces the electrolyte transport layer, has through-holes, which connect to the matrix, dispersely distributed. The electrolyte-transport layer is a thin sheet of a hydrophilic fibers which are non-wovens of such fibers as carbon, silicon carbide, silicon nitride or inorganic oxides. 11 figs.

  8. Evaluation of electricity production from alkaline pretreated sludge using two-chamber microbial fuel cell.

    Science.gov (United States)

    Xiao, Benyi; Yang, Fang; Liu, Junxin

    2013-06-15

    Electricity production from alkaline pretreated sludge was evaluated using a two-chamber microbial fuel cell (MFC). The electricity production was found to be stable over a long period of time (approximately 17 d) with voltage outputs and power densities of 0.47-0.52 V and 46.80-55.88 mW/m(2), respectively. The anode resistance was the main internal resistance (73.2%) of MFC in the stable stage. Most soluble organic matters (proteins and carbohydrates) in the anode chamber were first degraded and converted into volatile fatty acids (0-15 d), which were then degraded and converted into electricity and methane (15-29 d). The insoluble organics were solubilized thereby decreasing the sludge concentration and reducing the sludge mass. Methane was produced in the anode chamber owing to the growth of methanogens, which did not obviously affect the electricity production. The change in humic-like substances displayed a positive correlation with the electricity production of the MFC. Microbial analysis showed that methanogens and electricity-producing bacteria co-existed mostly on the surface as well as inside the anode. Decreasing the anode resistance and increasing the anode utilization could enhance the electricity production. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

  9. Performance enhancement of membrane electrode assemblies with plasma etched polymer electrolyte membrane in PEM fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Yong-Hun; Yoon, Won-Sub [School of Advanced Materials Engineering, Kookmin University, 861-1 Jeongneung-dong, Seongbuk-gu, Seoul 136-702 (Korea); Bae, Jin Woo; Cho, Yoon-Hwan; Lim, Ju Wan; Ahn, Minjeh; Jho, Jae Young; Sung, Yung-Eun [World Class University (WCU) program of Chemical Convergence for Energy and Environment (C2E2), School of Chemical and Biological Engineering, College of Engineering, Seoul National University (SNU), 599 Gwanak-Ro, Gwanak-gu, Seoul 151-744 (Korea); Kwon, Nak-Hyun [Fuel Cell Vehicle Team 3, Advanced Technology Center, Corporate Research and Development Division, Hyundai-Kia Motors, 104 Mabuk-dong, Giheung-gu, Yongin-si, Gyeonggi-do 446-912 (Korea)

    2010-10-15

    In this work, a surface modified Nafion 212 membrane was fabricated by plasma etching in order to enhance the performance of a membrane electrode assembly (MEA) in a polymer electrolyte membrane fuel cell. Single-cell performance of MEA at 0.7 V was increased by about 19% with membrane that was etched for 10 min compared to that with untreated Nafion 212 membrane. The MEA with membrane etched for 20 min exhibited a current density of 1700 mA cm{sup -2} at 0.35 V, which was 8% higher than that of MEA with untreated membrane (1580 mA cm{sup -2}). The performances of MEAs containing etched membranes were affected by complex factors such as the thickness and surface morphology of the membrane related to etching time. The structural changes and electrochemical properties of the MEAs with etched membranes were characterized by field emission scanning electron microscopy, Fourier transform-infrared spectrometry, electrochemical impedance spectroscopy, and cyclic voltammetry. (author)

  10. Transport phenomena in polymer electrolyte membrane fuel cells via voltage loss breakdown

    Science.gov (United States)

    Flick, Sarah; Dhanushkodi, Shankar R.; Mérida, Walter

    2015-04-01

    This study presents a voltage loss breakdown method based on in-situ experimental data to systematically analyze the different overpotentials of a polymer electrolyte membrane fuel cell. This study includes a systematic breakdown of the anodic overpotentials via the use of a reference electrode system. This work demonstrates the de-convolution of the individual overpotentials for both anode and cathode side, including the distinction between mass-transport overpotentials in cathode porous transport layer (PTL) and electrode, based on in-situ polarization tests under different operating conditions. This method is used to study the relationship between mass-transport losses inside the cathode catalyst layer (CL) and the PTL for both a single layer and two-layer PTL configuration. We conclude that the micro-porous layer (MPL) significantly improves the water removal within the cell, especially inside the cathode electrode, and therefore the mass transport within the cathode CL. This study supports the theory that the MPL on the cathode leads to an increase in water permeation from cathode to anode due to its function as a capillary barrier. This is reflected in increased anodic mass-transport overpotential, decreased ohmic losses and decreased cathode mass-transport losses, especially in the cathode electrode.

  11. Materials and characterization techniques for high-temperature polymer electrolyte membrane fuel cells.

    Science.gov (United States)

    Zeis, Roswitha

    2015-01-01

    The performance of high-temperature polymer electrolyte membrane fuel cells (HT-PEMFC) is critically dependent on the selection of materials and optimization of individual components. A conventional high-temperature membrane electrode assembly (HT-MEA) primarily consists of a polybenzimidazole (PBI)-type membrane containing phosphoric acid and two gas diffusion electrodes (GDE), the anode and the cathode, attached to the two surfaces of the membrane. This review article provides a survey on the materials implemented in state-of-the-art HT-MEAs. These materials must meet extremely demanding requirements because of the severe operating conditions of HT-PEMFCs. They need to be electrochemically and thermally stable in highly acidic environment. The polymer membranes should exhibit high proton conductivity in low-hydration and even anhydrous states. Of special concern for phosphoric-acid-doped PBI-type membranes is the acid loss and management during operation. The slow oxygen reduction reaction in HT-PEMFCs remains a challenge. Phosphoric acid tends to adsorb onto the surface of the platinum catalyst and therefore hampers the reaction kinetics. Additionally, the binder material plays a key role in regulating the hydrophobicity and hydrophilicity of the catalyst layer. Subsequently, the binder controls the electrode-membrane interface that establishes the triple phase boundary between proton conductive electrolyte, electron conductive catalyst, and reactant gases. Moreover, the elevated operating temperatures promote carbon corrosion and therefore degrade the integrity of the catalyst support. These are only some examples how materials properties affect the stability and performance of HT-PEMFCs. For this reason, materials characterization techniques for HT-PEMFCs, either in situ or ex situ, are highly beneficial. Significant progress has recently been made in this field, which enables us to gain a better understanding of underlying processes occurring during fuel cell

  12. Static and dynamic modeling of a diesel fuel processing unit for polymer electrolyte fuel cell supply

    Energy Technology Data Exchange (ETDEWEB)

    Chrenko, D.; Pera, M.C.; Hissel, D. [FCLAB, Femto-ST, UMR 6174, University of Franche-Comte, Techn' hom, Rue Thierry Mieg, 90010 Belfort (France); Coulie, J.; Lecoq, S. [N-GHY, Site Industriel Saint Antoine - ZI Montplaisir, 51 rue Isaac Newton, 81000 Albi (France)

    2009-02-15

    This article introduces the energetic macroscopic representation (EMR) as approach for the dynamic modeling of a diesel fuel processing unit. The EMR is the first step toward model-based control structure development. The autothermal fuel processing system containing: heat exchanger, reformer, desulfurization, water gas shift, preferential oxidation and condensation is divided into a multitude simple subblocks. Each subblock describes an elementary step of the fuel conversion, several of these blocks may occur in a single module. Calculations are carried out using two basic principles: mass and energy balances. For model-based control development, it is imperative that the model represents dynamic behavior, therefore temperature and pressure dynamics are taken into account in the model. It is shown that the model is capable to predict the stationary behavior of the entire fuel processing unit correctly by comparison with given data. Predictions regarding reformer heat up, temperature and pressure dynamics are also provided. (author)

  13. Energetics of Intermediate Temperature Solid Oxide Fuel Cell Electrolytes: Singly and Doubly doped Ceria Systems

    Science.gov (United States)

    Buyukkilic, Salih

    Solid oxide fuel cells (SOFCs) have potential to convert chemical energy directly to electrical energy with high efficiency, with only water vapor as a by-product. However, the requirement of extremely high operating temperatures (~1000 °C) limits the use of SOFCs to only in large scale stationary applications. In order to make SOFCs a viable energy solution, enormous effort has been focused on lowering the operating temperatures below 700 °C. A low temperature operation would reduce manufacturing costs by slowing component degradation, lessening thermal mismatch problems, and sharply reducing costs of operation. In order to optimize SOFC applications, it is critical to understand the thermodynamic stabilities of electrolytes since they directly influence device stability, sustainability and performance. Rare-earth doped ceria electrolytes have emerged as promising materials for SOFC applications due to their high ionic conductivity at the intermediate temperatures (500--700 °C). However there is a fundamental lack of understanding regarding their structure, thermodynamic stability and properties. Therefore, the enthalpies of formation from constituent oxides and ionic conductivities were determined to investigate a relationship between the stability, composition, structural defects and ionic conductivity in rare earth doped ceria systems. For singly doped ceria electrolytes, we investigated the solid solution phase of bulk Ce1-xLnxO2-0.5x where Ln = Sm and Nd (0 ≤ x ≤ 0.30) and analyzed their enthalpies of formation, mixing and association, and bulk ionic conductivities while considering cation size mismatch and defect associations. It was shown that for ambient temperatures in the dilute dopant region, the positive heat of formation reaches a maximum as the system becomes increasingly less stable due to size mismatch. In concentrated region, stabilization to a certain solubility limit was observed probably due to the defect association of trivalent cations

  14. A model-based parametric analysis of a direct ethanol polymer electrolyte membrane fuel cell performance

    Energy Technology Data Exchange (ETDEWEB)

    Andreadis, G.M.; Podias, A.K.M.; Tsiakaras, P.E. [Department of Mechanical and Industrial Engineering, School of Engineering, University of Thessaly, Pedion Areos, 383 34, Volos (Greece)

    2009-10-20

    In the present work, a model-based parametric analysis of the performance of a direct ethanol polymer electrolyte membrane fuel cell (DE-PEMFC) is conducted with the purpose to investigate the effect of several parameters on the cell's operation. The analysis is based on a previously validated one-dimensional mathematical model that describes the operation of a DE-PEMFC in steady state. More precisely, the effect of several operational and structural parameters on (i) the ethanol crossover rate from the anode to the cathode side of the cell, (ii) the parasitic current generation (mixed potential formation) and (iii) the total cell performance is investigated. According to the model predictions it was found that the increase of the ethanol feed concentration leads to higher ethanol crossover rates, higher parasitic currents and higher mixed potential values resulting in the decrease of the cell's power density. However there is an optimum ethanol feed concentration (approximately 1.0 mol L{sup -1}) for which the cell power density reaches its highest value. The platinum (Pt) loading of the anode and the cathode catalytic layers affects strongly the cell performance. Higher values of Pt loading of the catalytic layers increase the specific reaction surface area resulting in higher cell power densities. An increase of the anode catalyst loading compared to an equal one of the cathode catalyst loading has greater impact on the cell's power density. Another interesting finding is that increasing the diffusion layers' porosity up to a certain extent, improves the cell power density despite the fact that the parasitic current increases. This is explained by the fact that the reactants' concentrations over the catalysts are increased, leading to lower activation overpotential values, which are the main source of the total cell overpotentials. Moreover, the use of a thicker membrane leads to lower ethanol crossover rate, lower parasitic current and

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

    Science.gov (United States)

    Chen, Yi; Huang, Weina; Peng, Bei

    2014-01-01

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

  16. Thermal conductivity of catalyst layer of polymer electrolyte membrane fuel cells: Part 1 - Experimental study

    Science.gov (United States)

    Ahadi, Mohammad; Tam, Mickey; Saha, Madhu S.; Stumper, Jürgen; Bahrami, Majid

    2017-06-01

    In this work, a new methodology is proposed for measuring the through-plane thermal conductivity of catalyst layers (CLs) in polymer electrolyte membrane fuel cells. The proposed methodology is based on deconvolution of bulk thermal conductivity of a CL from measurements of two thicknesses of the CL, where the CLs are sandwiched in a stack made of two catalyst-coated substrates. Effects of hot-pressing, compression, measurement method, and substrate on the through-plane thermal conductivity of the CL are studied. For this purpose, different thicknesses of catalyst are coated on ethylene tetrafluoroethylene (ETFE) and aluminum (Al) substrates by a conventional Mayer bar coater and measured by scanning electron microscopy (SEM). The through-plane thermal conductivity of the CLs is measured by the well-known guarded heat flow (GHF) method as well as a recently developed transient plane source (TPS) method for thin films which modifies the original TPS thin film method. Measurements show that none of the studied factors has any effect on the through-plane thermal conductivity of the CL. GHF measurements of a non-hot-pressed CL on Al yield thermal conductivity of 0.214 ± 0.005 Wṡm-1ṡK-1, and TPS measurements of a hot-pressed CL on ETFE yield thermal conductivity of 0.218 ± 0.005 Wṡm-1ṡK-1.

  17. A Comprehensive Physical Impedance Model of Polymer Electrolyte Fuel Cell Cathodes in Oxygen-free Atmosphere.

    Science.gov (United States)

    Obermaier, Michael; Bandarenka, Aliaksandr S; Lohri-Tymozhynsky, Cyrill

    2018-03-21

    Electrochemical impedance spectroscopy (EIS) is an indispensable tool for non-destructive operando characterization of Polymer Electrolyte Fuel Cells (PEFCs). However, in order to interpret the PEFC's impedance response and understand the phenomena revealed by EIS, numerous semi-empirical or purely empirical models are used. In this work, a relatively simple model for PEFC cathode catalyst layers in absence of oxygen has been developed, where all the equivalent circuit parameters have an entire physical meaning. It is based on: (i) experimental quantification of the catalyst layer pore radii, (ii) application of De Levie's analytical formula to calculate the response of a single pore, (iii) approximating the ionomer distribution within every pore, (iv) accounting for the specific adsorption of sulfonate groups and (v) accounting for a small H 2 crossover through ~15 μm ionomer membranes. The derived model has effectively only 6 independent fitting parameters and each of them has clear physical meaning. It was used to investigate the cathode catalyst layer and the double layer capacitance at the interface between the ionomer/membrane and Pt-electrocatalyst. The model has demonstrated excellent results in fitting and interpretation of the impedance data under different relative humidities. A simple script enabling fitting of impedance data is provided as supporting information.

  18. Modeling the phenomena of dehydration and flooding of a polymer electrolyte membrane fuel cell

    Science.gov (United States)

    Gerteisen, Dietmar; Heilmann, Timothy; Ziegler, Christoph

    A one-dimensional, two-phase, transient PEM fuel cell model including gas diffusion layer, cathode catalyst layer and membrane is developed. The electrode is assumed to consist of a network of dispersed Pt/C forming spherically shaped agglomerated zones that are filled with electrolyte. Water is modeled in all three phases: vapor, liquid and dissolved in the ionomer to capture the effect of dehydration of the ionomer as well as flooding of the porous media. The anode is modeled as a sophisticated spatially reduced interface. Motivated by environmental scanning electron microscope (ESEM) images of contact angles for microscopic water droplets on fibers of the gas diffusion layer, we introduce the feature of immobile saturation. A step change of the saturation between the catalyst layer and the gas diffusion layer is modeled based on the assumption of a continuous capillary pressure at the interface. The model is validated against voltammetry experiments under various humidification conditions which all show hysteresis effects in the mass transport limited region. The transient saturation profiles clearly show that insufficient liquid water removal causes pore flooding, which is responsible for the oxygen mass transport limitation at high current density values. The simulated and measured current responses from chronoamperometry experiments are compared and analyzed.

  19. NEW POLYMER ELECTROLYTE MEMBRANES FOR FUEL CELLS OPERATING ABOVE 100°C

    DEFF Research Database (Denmark)

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

    2003-01-01

    The state-of-the-art of PEMFC technology is based on perfluorosulfonic acid (PFSA) polymer membranes operating at a typical temperature of 80°C. The newest development in the field is alternative polymer electrolytes for operation above 100°C. This paper is devoted to a review on the development...... and water management and possible integration with the fuel processing unit....

  20. New Polymer Electrolyte Membranes Based on Acid Doped PBI For Fuel Cells Operating above 100°C

    DEFF Research Database (Denmark)

    Li, Qingfeng

    2003-01-01

    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 opera...... 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....

  1. Selective oxidation of ethanol to acetic acid in highly efficient polymer electrolyte membrane-direct ethanol fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Bianchini, Claudio; Bambagioni, Valentina; Filippi, Jonathan; Marchionni, Andrea; Vizza, Francesco [Istituto di Chimica dei Composti Organometallici (ICCOM-CNR), National Research Council CNR, via Madonna del Piano 10, 50019 Sesto Fiorentino, FI (Italy); Bert, Paolo; Tampucci, Alessandro [ACTA SpA, via di lavoria 56/G, 56040 Crespina (PI) (Italy)

    2009-05-15

    The selective conversion of ethanol into potassium acetate with concomitant production of electrical energy has been achieved in both passive and active direct fuel cells containing platinum-free electrodes and an anion-exchange polymer membrane. The power densities supplied by the passive systems at r.t. can be as high as 55 mW cm{sup -2}, while the active systems can deliver up to 170 mW cm{sup -2} at 80 C. Such high values have never been reported for direct ethanol fuel cells with whatsoever electrocatalyst in either alkaline or acidic media. (author)

  2. Metal/ceria water-gas shift catalysts for automotive polymer electrolyte fuel cell system

    International Nuclear Information System (INIS)

    Myers, D. J.; Krebs, J. F.; Carter, J. D.; Kumar, R.; Krumpelt, M.

    2002-01-01

    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

  3. Assembly of a Cost-Effective Anode Using Palladium Nanoparticles for Alkaline Fuel Cell Applications

    Science.gov (United States)

    Feliciano-Ramos, Ileana; Casan~as-Montes, Barbara; García-Maldonado, María M.; Menendez, Christian L.; Mayol, Ana R.; Díaz-Vazquez, Liz M.; Cabrera, Carlos R.

    2015-01-01

    Nanotechnology allows the synthesis of nanoscale catalysts, which offer an efficient alternative for fuel cell applications. In this laboratory experiment, the student selects a cost-effective anode for fuel cells by comparing three different working electrodes. These are commercially available palladium (Pd) and glassy carbon (GC) electrodes, and…

  4. Imidazolium-based Block Copolymers as Solid-State Separators for Alkaline Fuel Cells and Lithium Ion Batteries

    Science.gov (United States)

    Nykaza, Jacob Richard

    In this study, polymerized ionic liquid (PIL) diblock copolymers were explored as solid-state polymer separators as an anion exchange membrane (AEM) for alkaline fuel cells AFCs and as a solid polymer electrolyte (SPE) for lithium-ion batteries. Polymerized ionic liquid (PIL) block copolymers are a distinct set of block copolymers that combine the properties of both ionic liquids (e.g., high conductivity, high electrochemical stability) and block copolymers (e.g., self-assembly into various nanostructures), which provides the opportunity to design highly conductive robust solid-state electrolytes that can be tuned for various applications including AFCs and lithium-ion batteries via simple anion exchange. A series of bromide conducting PIL diblock copolymers with an undecyl alkyl side chain between the polymer backbone and the imidazolium moiety were first synthesized at various compositions comprising of a PIL component and a non-ionic component. Synthesis was achieved by post-functionalization from its non-ionic precursor PIL diblock copolymer, which was synthesized via the reverse addition fragmentation chain transfer (RAFT) technique. This PIL diblock copolymer with long alkyl side chains resulted in flexible, transparent films with high mechanical strength and high bromide ion conductivity. The conductivity of the PIL diblock copolymer was three times higher than its analogous PIL homopolymer and an order of magnitude higher than a similar PIL diblock copolymer with shorter alkyl side chain length, which was due to the microphase separated morphology, more specifically, water/ion clusters within the PIL microdomains in the hydrated state. Due to the high conductivity and mechanical robustness of this novel PIL block copolymer, its application as both the ionomer and AEM in an AFC was investigated via anion exchange to hydroxide (OH-), where a maximum power density of 29.3 mW cm-1 (60 °C with H2/O2 at 25 psig (172 kPa) backpressure) was achieved. Rotating disk

  5. 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

    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....

  6. Electrochemically Promoted Organic Isomerization Reactions at Polymer Electrolyte Fuel Cell Cathodes

    Science.gov (United States)

    2011-01-04

    11 A fuel cell membrane electrode assembly uniquely enables study of the ionomer metal interface without interferences due to mobile anions character...carbon monoxide poisoning of fuel cell catalysts is of interest to our research group. Previous infrared studies of carbon monoxide poisoning in...Durability studies on performance degradation of catalysts and Nafion membrane in direct methanol fuel cells . In Abstracts of Papers, 240th ACS National

  7. In situ diagnostic of two-phase flow phenomena in polymer electrolyte fuel cells by neutron imaging

    International Nuclear Information System (INIS)

    Kramer, Denis; Zhang, Jianbo; Shimoi, Ryoichi; Lehmann, Eberhard; Wokaun, Alexander; Shinohara, Kazuhiko; Scherer, Guenther G.

    2005-01-01

    Neutron radiographical measurements have been performed on operating hydrogen-fueled polymer electrolyte fuel cells (PEFC). With the successful detection of liquid accumulation in flow field and gas diffusion layer (GDL) under various operating conditions a unique experimental approach for the investigation of two-phase flow phenomena in technical PEFC has been realized. The experimental setup will be described in detail. Algorithms for an enhanced quantitative evaluation of the obtained images are presented and successful application to the data demonstrated. Finally, results from PEFC investigations will be given. Different flow field geometries and their implications for liquid accumulation inside flow field and GDL are discussed

  8. Determination of optimum electrolyte composition for molten carbonate fuel cells literature review

    Science.gov (United States)

    Yuh, C. Y.; Pigeaud, A.

    1987-04-01

    Our review of the earlier cell testing data suggests that a more conductive electrolyte may improve total cell performance, primarily as a result of reduction of IR-loss in the electrolyte tile or matrix. This IR loss contributes significantly to cell performance loss. However, electrode performances could not be correlated very well with either potassium content or electrolyte conductivity, primarily due to possible off-setting effects in cathode kinetics, mass transfer, and ohmic resistance inside this porous electrode. The cell data discussed above concerned only short-term results and thus only the effects on performance were studied. The problems affecting endurance, e.g., corrosion, NiO dissolution, and matrix support stability could not be analyzed in these tests. This review therefore indicated that optimization of electrolyte composition is potentially available and could be beneficial to arrive at an optimum combination of performance/endurance and cost factors. Further systematic and careful experimental work will be necessary while emphasizing the need for repeatability and long-term stable and representative conditions.

  9. Effect of the hydrophilic and hydrophobic characteristics of the gas diffusion medium on polymer electrolyte fuel cell performance under non-humidification condition

    International Nuclear Information System (INIS)

    Park, Heesung

    2014-01-01

    Highlights: • GDM played significant role in the PEFC performance under dry condition. • Hydrophobicity of GDM affect the water condensation at the surface. • Optimum water saturation in the porous layer was between 0.1 and 0.3. - Abstract: Water is a significant component of polymer electrolyte fuel cells, affecting the proton conductivity in the membrane electrolyte. Therefore, polymer electrolyte fuel cells are generally operated with a humidifier to maintain a high relative humidity of the supplied gases; however, the humidifier contributes additional weight and cost. Although many studies have attempted to develop polymer electrolyte fuel cells without a humidifier, the studies have been mainly focused on the self-humidified membrane electrolyte and catalyst layer. In this paper, the author investigates the effect of polytetrafluoroethylene coated gas diffusion medium on the water content in the membrane electrolyte. The water condensation on the surfaces of the gas diffusion medium is visualised when the polymer electrolyte fuel cell is operated under non-humidification conditions. Numerical simulation suggests that the optimum water saturation is between 0.1 and 0.3 at the gas diffusion medium to hydrate the membrane electrolyte sufficiently without significantly blocking the diffused species under non-humidification conditions

  10. Phenomenological theory of current-producing processes at the solid oxide electrolyte/gas electrode interface: steady-state polarization of fuel-cell electrodes

    International Nuclear Information System (INIS)

    Murygin, I.V.; Chebotin, V.N.

    1979-01-01

    The polarization of fuel-cell electrodes (mixtures CO + CO 2 and H 2 + H 2 O) in systems with solid oxide electrolytes is discussed. The theory is based upon a process model where the electrode reaction zone can spread along the line of three-phase contact by diffusion of reaction partners and products across the electrolyte/electrode and electrolyte/gas interface

  11. Detonation nanodiamond introduced into samarium doped ceria electrolyte improving performance of solid oxide fuel cell

    Science.gov (United States)

    Pei, Kai; Li, Hongdong; Zou, Guangtian; Yu, Richeng; Zhao, Haofei; Shen, Xi; Wang, Liying; Song, Yanpeng; Qiu, Dongchao

    2017-02-01

    A novel electrolyte materials of introducing detonation nanodiamond (DNDs) into samarium doped ceria (SDC) is reported here. 1%wt. DNDs doping SDC (named SDC/ND) can enlarge the electrotyle grain size and change the valence of partial ceria. DNDs provide the widen channel to accelerate the mobility of oxygen ions in electrolyte. Larger grain size means that oxygen ions move easier in electrolyte, it can also reduce the alternating current (AC) impedance spectra of internal grains. The lower valence of partial Ce provides more oxygen vacancies to enhance mobility rate of oxygen ions. Hence all of them enhance the transportation of oxygen ions in SDC/ND electrolyte and the OCV. Ultimately the power density of SOFC can reach 762 mw cm-2 at 800 °C (twice higher than pure SDC, which is 319 mw cm-2 at 800 °C), and it remains high power density in the intermediate temperature (600-800 °C). It is relatively high for the electrolyte supported (300 μm) cells.

  12. 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; Jensen, Hans-Christian Becker

    This work involves the an experimental characterisation and the development of control strategies for the methanol reformer system used in the Serenergy Serenus H3 E-350 high temperature polymer electrolyte membrane (HTPEM) fuel cell system. The system consists of a fuel evaporator utilizing...... the high temperature waste gas from a cathode air cooled 45 cell HTPEM fuel cell stack. The MEAs used are BASF P2100 which use phosphoric acid doped polybenzimidazole type membranes; an MEA with high CO tolerance and no complex humidity requirements. The methanol reformer used is integrated into a compact......, i.e. cathode and anode gas flows and temperature by using mass flow controllers and controlled heaters. Using this system the methanol reformer is characterized in its different operating points, both steady-state but also dynamically. Methanol steam reforming is a well known process, and provides...

  13. Platinum and palladium nano-structured catalysts for polymer electrolyte fuel cells and direct methanol fuel cells.

    Science.gov (United States)

    Long, Nguyen Viet; Thi, Cao Minh; Yong, Yang; Nogami, Masayuki; Ohtaki, Michitaka

    2013-07-01

    In this review, we present the synthesis and characterization of Pt, Pd, Pt based bimetallic and multi-metallic nanoparticles with mixture, alloy and core-shell structure for nano-catalysis, energy conversion, and fuel cells. Here, Pt and Pd nanoparticles with modified nanostructures can be controllably synthesized via chemistry and physics for their uses as electro-catalysts. The cheap base metal catalysts can be studied in the relationship of crystal structure, size, morphology, shape, and composition for new catalysts with low cost. Thus, Pt based alloy and core-shell catalysts can be prepared with the thin Pt and Pt-Pd shell, which are proposed in low and high temperature proton exchange membrane fuel cells (PEMFCs), and direct methanol fuel cells (DMFCs). We also present the survey of the preparation of Pt and Pd based catalysts for the better catalytic activity, high durability, and stability. The structural transformations, quantum-size effects, and characterization of Pt and Pd based catalysts in the size ranges of 30 nm (1-30 nm) are presented in electro-catalysis. In the size range of 10 nm (1-10 nm), the pure Pt catalyst shows very large surface area for electro-catalysis. To achieve homogeneous size distribution, the shaped synthesis of the polyhedral Pt nanoparticles is presented. The new concept of shaping specific shapes and morphologies in the entire nano-scale from nano to micro, such as polyhedral, cube, octahedra, tetrahedra, bar, rod, and others of the nanoparticles is proposed, especially for noble and cheap metals. The uniform Pt based nanosystems of surface structure, internal structure, shape, and morphology in the nanosized ranges are very crucial to next fuel cells. Finally, the modifications of Pt and Pd based catalysts of alloy, core-shell, and mixture structures lead to find high catalytic activity, durability, and stability for nano-catalysis, energy conversion, fuel cells, especially the next large-scale commercialization of next

  14. High-performance bilayered electrolyte intermediate temperature solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Jin Soo; Camaratta, Matthew A.; Yoon, Heesung; Lee, Byung Wook; Lee, Kang Taek; Jung, Doh Won; Wachsman, Eric D. [Department of Materials Science and Engineering, University for Florida, Gainesville, FL 32611 (United States); Pergolesi, Daniele; Traversa, Enrico [Department of Chemical Science of Technology, University of Rome Tor Vergata, Via della Ricerca Scientifica, 1, Rome 00133 (Italy); International Research Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

    2009-07-15

    The ESB/GDC bilayer electrolyte concept has been proved to improve open circuit voltage and reduce the effective area specific resistance of SOFCs utilizing a conventional single-layer GDC electrolyte. However, high performance from such bilayer cells had not yet been demonstrated. The main obstacles toward this end have been fabrication of anode-supported thin-film electrolytes and the reactivity of ESB with conventional cathodes. Recently, an ESB-compatible low area specific resistance cathode was developed: microstructurally optimized Bi{sub 2}Ru{sub 2}O{sub 7}-ESB composites. In addition, we recently developed a novel anode functional layer which can significantly enhance the performance of SOFC utilizing GDC electrolytes. This study combines these recent achievements in SOFC studies and shows that exceptionally high performance of SOFC is possible using ESB/GDC bilayer electrolytes and Bi{sub 2}Ru{sub 2}O{sub 7}-ESB composite cathodes. The result confirms that the bilayer electrolyte and the Bi{sub 2}Ru{sub 2}O{sub 7}-ESB cathode can increase the open circuit potential and reduce the total area specific resistance. The maximum power density of the bilayered SOFC was improved to 1.95 W cm{sup -2} with 0.079 {omega} cm{sup 2} total cell area specific resistance at 650 C. This is the highest power yet achieved in the IT range and we believe redefines the expectation level for maximum power under IT-SOFC operating conditions. (author)

  15. Local electrochemical characteristics at various operating pressure and temperature values using a segmented polymer electrolyte membrane fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Sang; Kim, Dong Kyu; Kim, Min Soo [Dept. Mechanical and Aerospace Engineering, Seoul National University, Seoul (Korea, Republic of); Kong, Im Mo [Korea Automotive Technology Institute, Gwangju (Korea, Republic of); Kim, Min Sung [School of Energy Systems Engineering, Chung-Ang University, Seoul (Korea, Republic of)

    2016-09-15

    The pressurization of reactant gases is one of the solutions for generating considerable power in a polymer electrolyte membrane fuel cell with a restricted size. Electrochemical phenomena, such as current density distribution and ohmic resistance distribution, were observed to validate the effects of operating pressure and temperature on cell performance. The test was conducted in galvanostatic mode, and an inhomogeneous current distribution was observed under a high-pressure condition, except at a high temperature. High-frequency resistance measurement was also conducted to observe local ohmic resistance. Result showed that high pressure and temperature reduced ohmic loss and improved overall cell performance.

  16. Probing platinum degradation in polymer electrolyte membrane fuel cells by synchrotron X-ray microscopy.

    Science.gov (United States)

    Berejnov, Viatcheslav; Martin, Zulima; West, Marcia; Kundu, Sumit; Bessarabov, Dmitri; Stumper, Jürgen; Susac, Darija; Hitchcock, Adam P

    2012-04-14

    Synchrotron-based scanning transmission X-ray spectromicroscopy (STXM) was used to characterize the local chemical environment at and around the platinum particles in the membrane (PTIM) which form in operationally tested (end-of-life, EOL) catalyst coated membranes (CCMs) of polymer electrolyte membrane fuel cells (PEM-FC). The band of metallic Pt particles in operationally tested CCM membranes was imaged using transmission electron microscopy (TEM). The cathode catalyst layer in the beginning-of-life (BOL) CCMs was fabricated using commercially available catalysts created from Pt precursors with and without nitrogen containing ligands. The surface composition of these catalyst powders was measured by X-ray Photoelectron Spectroscopy (XPS). The local chemical environment of the PTIM in EOL CCMs was found to be directly related to the Pt precursor used in CCM fabrication. STXM chemical mapping at the N 1s edge revealed a characteristic spectrum at and around the dendritic Pt particles in CCMs fabricated with nitrogen containing Pt-precursors. This N 1s spectrum was identical to that of the cathode and different from the membrane. For CCM samples fabricated without nitrogen containing Pt-precursors the N 1s spectrum at the Pt particles was indistinguishable from that of the adjacent membrane. We interpret these observations to indicate that nitrogenous ligands in the nitrogen containing precursors, or decomposition product(s) from that source, are transported together with the dissolved Pt from the cathode into the membrane as a result of the catalyst degradation process. This places constraints on possible mechanisms for the PTIM band formation process.

  17. Chemically durable polymer electrolytes for solid-state alkaline water electrolysis

    Science.gov (United States)

    Park, Eun Joo; Capuano, Christopher B.; Ayers, Katherine E.; Bae, Chulsung

    2018-01-01

    Generation of high purity hydrogen using electrochemical splitting of water is one of the most promising methods for sustainable fuel production. The materials to be used as solid-state electrolytes for alkaline water electrolyzer require high thermochemical stability against hydroxide ion attack in alkaline environment during the operation of electrolysis. In this study, two quaternary ammonium-tethered aromatic polymers were synthesized and investigated for anion exchange membrane (AEM)-based alkaline water electrolyzer. The membranes properties including ion exchange capacity (IEC), water uptake, swelling degree, and anion conductivity were studied. The membranes composed of all C-C bond polymer backbones and flexible side chain terminated by cation head groups exhibited remarkably good chemical stability by maintaining structural integrity in 1 M NaOH solution at 95 °C for 60 days. Initial electrochemical performance and steady-state operation performance were evaluated, and both membranes showed a good stabilization of the cell voltage during the steady-state operation at the constant current density at 200 mA/cm2. Although both membranes in current form require improvement in mechanical stability to afford better durability in electrolysis operation, the next generation AEMs based on this report could lead to potentially viable AEM candidates which can provide high electrolysis performance under alkaline operating condition.

  18. A new modified-serpentine flow field for application in high temperature polymer electrolyte fuel cell

    DEFF Research Database (Denmark)

    Singdeo, Debanand; Dey, Tapobrata; Gaikwad, Shrihari

    2017-01-01

    Flow field design for the distribution of reactants and products on the electrode surface plays an important role in the overall performance of the fuel cell. It acts as a crucial factor when the laboratory scale fuel cell is scaled up for commercial applications. In the present work, a novel flo...

  19. 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

    life time of a fuel cell significantly. On air cooled HTPEMFCs, the blower, which supplies the fuel cell with oxygen for the chemical process, also functions as the cooling system. This makes the blower bi-functional and as a result a higher supply of oxygen is often available, hence changes...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-11-01

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

  1. Enhancement of co-tolerance in polymer electrolyte fuel cells by increased cell temperature

    Energy Technology Data Exchange (ETDEWEB)

    Hajbolouri, F.; Andreaus, B.; Scherer, G.; Wokaun A

    2003-03-01

    AC-impedance spectroscopy has been employed to investigate the temperature dependence of CO-poisoning in a 30 cm{sup 2} fuel cell for commercial Pt E-tek electrodes. An inductive behavior was shown to be characteristic for the CO-poisoning on Pt at higher current densities, above 200 mA/cm{sup 2}, and for CO-contents higher than 50 ppm. At lower current densities where the CO-oxidation is slight or negligible no inductive behavior was observed. The increase of cell temperature from 90 {sup o}C to 100 {sup o}C decreased the charge transfer resistivity by a factor of 4. A simple model was established for a quantitative analysis of CO-poisoning. (author)

  2. 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...

  3. Effect of proton-conduction in electrolyte on electric efficiency of multi-stage solid oxide fuel cells.

    Science.gov (United States)

    Matsuzaki, Yoshio; Tachikawa, Yuya; Somekawa, Takaaki; Hatae, Toru; Matsumoto, Hiroshige; Taniguchi, Shunsuke; Sasaki, Kazunari

    2015-07-28

    Solid oxide fuel cells (SOFCs) are promising electrochemical devices that enable the highest fuel-to-electricity conversion efficiencies under high operating temperatures. The concept of multi-stage electrochemical oxidation using SOFCs has been proposed and studied over the past several decades for further improving the electrical efficiency. However, the improvement is limited by fuel dilution downstream of the fuel flow. Therefore, evolved technologies are required to achieve considerably higher electrical efficiencies. Here we present an innovative concept for a critically-high fuel-to-electricity conversion efficiency of up to 85% based on the lower heating value (LHV), in which a high-temperature multi-stage electrochemical oxidation is combined with a proton-conducting solid electrolyte. Switching a solid electrolyte material from a conventional oxide-ion conducting material to a proton-conducting material under the high-temperature multi-stage electrochemical oxidation mechanism has proven to be highly advantageous for the electrical efficiency. The DC efficiency of 85% (LHV) corresponds to a net AC efficiency of approximately 76% (LHV), where the net AC efficiency refers to the transmission-end AC efficiency. This evolved concept will yield a considerably higher efficiency with a much smaller generation capacity than the state-of-the-art several tens-of-MW-class most advanced combined cycle (MACC).

  4. Effect of proton-conduction in electrolyte on electric efficiency of multi-stage solid oxide fuel cells

    Science.gov (United States)

    Matsuzaki, Yoshio; Tachikawa, Yuya; Somekawa, Takaaki; Hatae, Toru; Matsumoto, Hiroshige; Taniguchi, Shunsuke; Sasaki, Kazunari

    2015-01-01

    Solid oxide fuel cells (SOFCs) are promising electrochemical devices that enable the highest fuel-to-electricity conversion efficiencies under high operating temperatures. The concept of multi-stage electrochemical oxidation using SOFCs has been proposed and studied over the past several decades for further improving the electrical efficiency. However, the improvement is limited by fuel dilution downstream of the fuel flow. Therefore, evolved technologies are required to achieve considerably higher electrical efficiencies. Here we present an innovative concept for a critically-high fuel-to-electricity conversion efficiency of up to 85% based on the lower heating value (LHV), in which a high-temperature multi-stage electrochemical oxidation is combined with a proton-conducting solid electrolyte. Switching a solid electrolyte material from a conventional oxide-ion conducting material to a proton-conducting material under the high-temperature multi-stage electrochemical oxidation mechanism has proven to be highly advantageous for the electrical efficiency. The DC efficiency of 85% (LHV) corresponds to a net AC efficiency of approximately 76% (LHV), where the net AC efficiency refers to the transmission-end AC efficiency. This evolved concept will yield a considerably higher efficiency with a much smaller generation capacity than the state-of-the-art several tens-of-MW-class most advanced combined cycle (MACC). PMID:26218470

  5. Effect of proton-conduction in electrolyte on electric efficiency of multi-stage solid oxide fuel cells

    Science.gov (United States)

    Matsuzaki, Yoshio; Tachikawa, Yuya; Somekawa, Takaaki; Hatae, Toru; Matsumoto, Hiroshige; Taniguchi, Shunsuke; Sasaki, Kazunari

    2015-07-01

    Solid oxide fuel cells (SOFCs) are promising electrochemical devices that enable the highest fuel-to-electricity conversion efficiencies under high operating temperatures. The concept of multi-stage electrochemical oxidation using SOFCs has been proposed and studied over the past several decades for further improving the electrical efficiency. However, the improvement is limited by fuel dilution downstream of the fuel flow. Therefore, evolved technologies are required to achieve considerably higher electrical efficiencies. Here we present an innovative concept for a critically-high fuel-to-electricity conversion efficiency of up to 85% based on the lower heating value (LHV), in which a high-temperature multi-stage electrochemical oxidation is combined with a proton-conducting solid electrolyte. Switching a solid electrolyte material from a conventional oxide-ion conducting material to a proton-conducting material under the high-temperature multi-stage electrochemical oxidation mechanism has proven to be highly advantageous for the electrical efficiency. The DC efficiency of 85% (LHV) corresponds to a net AC efficiency of approximately 76% (LHV), where the net AC efficiency refers to the transmission-end AC efficiency. This evolved concept will yield a considerably higher efficiency with a much smaller generation capacity than the state-of-the-art several tens-of-MW-class most advanced combined cycle (MACC).

  6. Effects of the operational conditions on the membrane and electrode properties of a polymer electrolyte fuel cell

    Directory of Open Access Journals (Sweden)

    Passos Raimundo R.

    2002-01-01

    Full Text Available The effects of the operational conditions on the membrane and electrode properties on a polymer electrolyte fuel cell (PEFC were investigated as a function of the cell and the gas humidifiers temperatures, the thickness of the membrane, the impregnation with phosphotungstic acid (PWA, and the variation of the Nafion and Teflon contents in the gas diffusion electrodes. An increase of the membrane resistance was observed when the PEFC is operated at temperatures equal or higher than those of the gas humidifiers, and this is more apparent for thicker electrolyte films. In the presence of PWA, the physicochemical properties of the membrane do not appreciably change with temperature. However, in this case, a lower humidification temperature affects the electrode performance. Changes on the Nafion loading in the electrodes do not lead to any significant effect in the electrode and membrane properties. For high Teflon contents there is a small lowering of the membrane conductivity.

  7. Performance enhancement of polymer electrolyte membrane fuel cells by dual-layered membrane electrode assembly structures with carbon nanotubes.

    Science.gov (United States)

    Jung, Dong-Won; Kim, Jun-Ho; Kim, Se-Hoon; Kim, Jun-Bom; Oh, Eun-Suok

    2013-05-01

    The effect of dual-layered membrane electrode assemblies (d-MEAs) on the performance of a polymer electrolyte membrane fuel cell (PEMFC) was investigated using the following characterization techniques: single cell performance test, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). It has been shown that the PEMFC with d-MEAs has better cell performance than that with typical mono-layered MEAs (m-MEAs). In particular, the d-MEA whose inner layer is composed of multi-walled carbon nanotubes (MWCNTs) showed the best fuel cell performance. This is due to the fact that the d-MEAs with MWCNTs have the highest electrochemical surface area and the lowest activation polarization, as observed from the CV and EIS test.

  8. 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.

  9. Dynamic NMR studies of polymer electrolyte materials for application to lithium-ion batteries and fuel cells

    Science.gov (United States)

    Khalfan, Amish N.

    This dissertation investigates the structural and dynamical properties of polymer electrolyte materials for applications to lithium-ion batteries and fuel cells. The nuclear magnetic resonance (NMR) technique was used to characterize these materials. NMR aids in understanding the local environments of nuclei and the mobility of a molecular/ionic species. Five research projects were carried out, and they have been outlined in this work. NASA has developed rod-coil block copolymers for use as electrolytes in lithium-ion batteries. The copolymers exhibit a microphase separation within their structure leading to the formation of ionically conducting channels. We studied ion transport properties of the copolymers, and determined the predominant mechanism for transport to occur in the amorphous phase. Seven gel polymer electrolytes, each containing a mixture of LiBETI salt and organic solvents, were studied. Two of them incorporated BMI (1-n-butyl-3-methylimidazolium) ionic liquid. Ionic liquids are room temperature molten salts. BMI had been thought to enhance ion mobility. However, the BMI component was observed to restrict ion mobility. Gel polymer electrolytes containing LiTFSI salt and P13TFSI ionic liquid with or without the inclusion of ethylene carbonate (EC) were studied for application to lithium metal/air batteries, which have high theoretical energy densities. The addition of EC was found to improve lithium ion transport. The gels with EC therefore prove to be favorable for use as electrolytes in lithium metal/air batteries. Highly sulfonated poly(arylenethioethersulfone) (SPTES) membranes were examined for use in direct methanol fuel cells (DMFCs) as an alternative to the Nafion membrane. DMFCs use methanol as a fuel instead of reformed hydrogen as in conventional proton exchange membrane fuel cells. Compared to Nafion, the SPTES membranes were shown to retain water better at high temperatures and yield lower methanol diffusion. SPTES membranes with the

  10. Graphene-cobaltite-Pd hybrid materials for use as efficient bifunctional electrocatalysts in alkaline direct methanol fuel cells.

    Science.gov (United States)

    Sharma, Chandra Shekhar; Awasthi, Rahul; Singh, Ravindra Nath; Sinha, Akhoury Sudhir Kumar

    2013-12-14

    Hybrid materials comprising of Pd, MCo2O4 (where M = Mn, Co or Ni) and graphene have been prepared for use as efficient bifunctional electrocatalysts in alkaline direct methanol fuel cells. Structural and electrochemical characterizations were carried out using X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, chronoamperometry and cyclic, CO stripping, and linear sweep voltammetries. The study revealed that all the three hybrid materials are active for both methanol oxidation (MOR) and oxygen reduction (ORR) reactions in 1 M KOH. However, the Pd-MnCo2O4/GNS hybrid electrode exhibited the greatest MOR and ORR activities. This active hybrid electrode has also outstanding stability under both MOR and ORR conditions, while Pt- and other Pd-based catalysts undergo degradation under similar experimental conditions. The Pd-MnCo2O4/GNS hybrid catalyst exhibited superior ORR activity and stability compared to even Pt in alkaline solutions.

  11. Improved Fuel Transport Selectivity in Polymer Electrolyte Membranes

    OpenAIRE

    Clark, Kyle Tyler

    2014-01-01

    In polymer electrolyte membrane (PEM) fuel cells, fuel crossover through the membrane is a significant problem that contributes to reduction in cell efficiency and accelerated membrane degradation. The need for high water content in the membrane to produce acceptable conductivities leads to excessive fuel crossover while also limiting cell operating temperature to

  12. Hardware/Software Data Acquisition System for Real Time Cell Temperature Monitoring in Air-Cooled Polymer Electrolyte Fuel Cells

    Directory of Open Access Journals (Sweden)

    Francisca Segura

    2017-07-01

    Full Text Available This work presents a hardware/software data acquisition system developed for monitoring the temperature in real time of the cells in Air-Cooled Polymer Electrolyte Fuel Cells (AC-PEFC. These fuel cells are of great interest because they can carry out, in a single operation, the processes of oxidation and refrigeration. This allows reduction of weight, volume, cost and complexity of the control system in the AC-PEFC. In this type of PEFC (and in general in any PEFC, the reliable monitoring of temperature along the entire surface of the stack is fundamental, since a suitable temperature and a regular distribution thereof, are key for a better performance of the stack and a longer lifetime under the best operating conditions. The developed data acquisition (DAQ system can perform non-intrusive temperature measurements of each individual cell of an AC-PEFC stack of any power (from watts to kilowatts. The stack power is related to the temperature gradient; i.e., a higher power corresponds to a higher stack surface, and consequently higher temperature difference between the coldest and the hottest point. The developed DAQ system has been implemented with the low-cost open-source platform Arduino, and it is completed with a modular virtual instrument that has been developed using NI LabVIEW. Temperature vs time evolution of all the cells of an AC-PEFC both together and individually can be registered and supervised. The paper explains comprehensively the developed DAQ system together with experimental results that demonstrate the suitability of the system.

  13. Hardware/Software Data Acquisition System for Real Time Cell Temperature Monitoring in Air-Cooled Polymer Electrolyte Fuel Cells.

    Science.gov (United States)

    Segura, Francisca; Bartolucci, Veronica; Andújar, José Manuel

    2017-07-09

    This work presents a hardware/software data acquisition system developed for monitoring the temperature in real time of the cells in Air-Cooled Polymer Electrolyte Fuel Cells (AC-PEFC). These fuel cells are of great interest because they can carry out, in a single operation, the processes of oxidation and refrigeration. This allows reduction of weight, volume, cost and complexity of the control system in the AC-PEFC. In this type of PEFC (and in general in any PEFC), the reliable monitoring of temperature along the entire surface of the stack is fundamental, since a suitable temperature and a regular distribution thereof, are key for a better performance of the stack and a longer lifetime under the best operating conditions. The developed data acquisition (DAQ) system can perform non-intrusive temperature measurements of each individual cell of an AC-PEFC stack of any power (from watts to kilowatts). The stack power is related to the temperature gradient; i.e., a higher power corresponds to a higher stack surface, and consequently higher temperature difference between the coldest and the hottest point. The developed DAQ system has been implemented with the low-cost open-source platform Arduino, and it is completed with a modular virtual instrument that has been developed using NI LabVIEW. Temperature vs time evolution of all the cells of an AC-PEFC both together and individually can be registered and supervised. The paper explains comprehensively the developed DAQ system together with experimental results that demonstrate the suitability of the system.

  14. Obtaining of ceria - samaria - gadolinia ceramics for application as solid oxide fuel cell (SOFC) electrolyte

    International Nuclear Information System (INIS)

    Arakaki, Alexander Rodrigo

    2010-01-01

    Cerium oxide (CeO 2 ) 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 - Sm 2 O 3 ) and gadolinia (gadolinium oxide - Gd 2 O 3 ), fixing the concentration between 10 and 20 molar%. In this work, Ce 0,8 (SmGd) 0,2 O 1,9 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 CeO 2 and other containing 51% of Sm 2 O 3 and 30% of Gd 2 O 3 , 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 m 2 .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 m 2 .g -1

  15. Fabrication of novel nanomaterials for polymer electrolyte membrane fuel cells and self-cleaning applications

    Science.gov (United States)

    Zhang, Lei

    Materials scientists have embraced nanoscale materials as allowing new degrees of freedom in materials design, as well as producing completely new and enhanced properties compared with conventional materials. However, most nanofabrication methods are tedious and expensive, or require extreme conditions. This thesis presents efficient methods for generating nanostructured materials under relatively mild chemistry and experimental conditions. The basis of most of this work is porous anodic aluminum oxide (p-AAO) membranes, which have hexagonally close-packed pores and were fabricated following a two-step aluminum anodization procedure. Partially removing the barrier layer of a p-AAO membrane enabled the preparation of silver nanorod arrays using a very simple electrodepostition procedure. One dimensional (1-D) alumina nanostructures were also electrochemically synthesized on the surface of a p-AAO membrane by carefully controlling the anodization parameters. Polyacrylonitrile nanofibers containing platinum salt were fabricated by polymerization of acrylonitrile in p-AAO templates. Subsequent pyrolysis resulted in carbon nanofibers wherein the platinum salt is reduced in-situ to elemental Pt. The Pt nanoparticles are dispersed throughout the carbon nanofibers, have a narrow size range, and are single crystals. Rotating disc electrode voltammetry suggests that the dispersion of Pt nanocrystals in the carbon nanofiber matrix should exhibit excellent electrocatalytic activity. The preparation of catalyst ink and the construction of membrane-electrode-assembly need to be optimized to get better performance in polymer electrolyte membrane fuel cells. Platinum nanoparticles embedded in carbon fibers were also prepared using electrospinning. The prepared platinum nanoparticles are narrowly distributed in size and well dispersed in the carbon matrix. This method can provide a large yield of products with a simple setup and procedure. 2-D arrays of nanopillars made from

  16. Polymer electrolyte membranes for fuel cells by radiation induced grafting with electron beam irradiation: state-of-the-art

    International Nuclear Information System (INIS)

    Nasef, M.M.; Nasef, M.M.

    2010-01-01

    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

  17. 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.

  18. 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...... with Ni seed layer coated by a multi-layered graphene thin film (G/Ni/SS). The graphene film, synthesized by chemical vapour deposition (CVD), has a moderate amount of defects according to Raman spectroscopy. Short/medium-term corrosion test shows no significant advantage of using G/Ni/SS rather than Ni...

  19. 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...... 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...

  20. Exploratory fuel-cell research: I. Direct-hydrocarbon polymer-electrolyte fuel cell. II. Mathematical modeling of fuel-cell cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Perry, Michael L. [Univ. of California, Berkeley, CA (United States)

    1996-12-01

    A strong need exists today for more efficient energy-conversion systems. Our reliance on limited fuel resources, such as petroleum for the majority of our energy needs makes it imperative that we utilize these resources as efficiently as possible. Higher-efficiency energy conversion also means less pollution, since less fuel is consumed and less exhaust created for the same energy output. Additionally, for many industrialized nations, such as the United States which must rely on petroleum imports, it is also imperative from a national-security standpoint to reduce the consumption of these precious resources. A substantial reduction of U.S. oil imports would result in a significant reduction of our trade deficit, as well as costly military spending to protect overseas petroleum resources. Therefore, energy-conversion devices which may utilize alternative fuels are also in strong demand. This paper describes research on fuel cells for transportation.

  1. Operando 3D Visualization of Migration and Degradation of a Platinum Cathode Catalyst in a Polymer Electrolyte Fuel Cell.

    Science.gov (United States)

    Matsui, Hirosuke; Ishiguro, Nozomu; Uruga, Tomoya; Sekizawa, Oki; Higashi, Kotaro; Maejima, Naoyuki; Tada, Mizuki

    2017-08-01

    The three-dimensional (3D) distribution and oxidation state of a Pt cathode catalyst in a practical membrane electrode assembly (MEA) were visualized in a practical polymer electrolyte fuel cell (PEFC) under fuel-cell operating conditions. Operando 3D computed-tomography imaging with X-ray absorption near edge structure (XANES) spectroscopy (CT-XANES) clearly revealed the heterogeneous migration and degradation of Pt cathode catalyst in an MEA during accelerated degradation test (ADT) of PEFC. The degradative Pt migration proceeded over the entire cathode catalyst layer and spread to MEA depth direction into the Nafion membrane. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Development of nano-composite membranes to improve alkaline fuel cell performance

    CSIR Research Space (South Africa)

    Nonjola, P

    2011-09-01

    Full Text Available ] A.S. Aricoa, S. Srinivasan, V. Antonuccia, Fuel Cells 1 (2001) p133 [4] X. Ren, P. Zelenay, S. Thomas, J. Davey, S. Gottesfeld, J. Power Sources 86 (2000) p111 [5] Y. Shao, G. Yin, Z. Wang, Y. Gao, J. Power Sources 167 (2007) p235 [6] J. Fang, P...

  3. 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

  4. Performance comparison of protonic and sodium phosphomolybdovanadate polyoxoanion catholytes within a chemically regenerative redox cathode polymer electrolyte fuel cell

    Science.gov (United States)

    Ward, David B.; Gunn, Natasha L. O.; Uwigena, Nadine; Davies, Trevor J.

    2018-01-01

    The direct reduction of oxygen in conventional polymer electrolyte fuel cells (PEFCs) is seen by many researchers as a key challenge in PEFC development. Chemically regenerative redox cathode (CRRC) polymer electrolyte fuel cells offer an alternative approach via the indirect reduction of oxygen, improving durability and reducing cost. These systems substitute gaseous oxygen for a liquid catalyst that is reduced at the cathode then oxidised in a regeneration vessel via air bubbling. A key component of a CRRC system is the liquid catalyst or catholyte. To date, phosphomolybdovanadium polyoxometalates with empirical formula H3+nPVnMo12-nO40 have shown the most promise for CRRC PEFC systems. In this work, four catholyte formulations are studied and compared against each other. The catholytes vary in vanadium content, pH and counter ion, with empirical formulas H6PV3Mo9O40, H7PV4Mo8O40, Na3H3PV3Mo9O40 and Na4H3PV4Mo8O40. Thermodynamic properties, cell performance and regeneration rates are measured, generating new insights into how formulation chemistry affects the components of a CRRC system. The results include the best CRRC PEFC performance reported to date, with noticeable advantages over conventional PEFCs. The optimum catholyte formulation is then determined via steady state tests, the results of which will guide further optimization of the catholyte formulation.

  5. Novel electrospun gas diffusion layers for polymer electrolyte membrane fuel cells: Part I. Fabrication, morphological characterization, and in situ performance

    Science.gov (United States)

    Chevalier, S.; Lavielle, N.; Hatton, B. D.; Bazylak, A.

    2017-06-01

    In this first of a series of two papers, we report an in-depth analysis of the impact of the gas diffusion layer (GDL) structure on the polymer electrolyte membrane (PEM) fuel cell performance through the use of custom GDLs fabricated in-house. Hydrophobic electrospun nanofibrous gas diffusion layers (eGDLs) are fabricated with controlled fibre diameter and alignment. The eGDLs are rendered hydrophobic through direct surface functionalization, and this molecular grafting is achieved in the absence of structural alteration. The fibre diameter, chemical composition, and electrical conductivity of the eGDL are characterized, and the impact of eGDL structure on fuel cell performance is analysed. We observe that the eGDL facilitates higher fuel cell power densities compared to a commercial GDL (Toray TGP-H-60) at highly humidified operating conditions. The ohmic resistance of the fuel cell is found to significantly increase with increasing inter-fiber distance. It is also observed that the addition of a hydrophobic treatment enhances membrane hydration, and fibres perpendicularly aligned to the channel direction may enhance the contact area between the catalyst layer and the GDL.

  6. Electrochemical characterization on SDC/Na2CO3 nanocomposite electrolyte for low temperature solid oxide fuel cells.

    Science.gov (United States)

    Gao, Zhan; Raza, Rizwan; Zhu, Bin; Mao, Zongqiang

    2011-06-01

    Our previous work has demonstrated that novel core-shell SDC/Na2CO3 nanocomposite electrolyte possesses great potential for the development of low temperature (300-600 degrees C) solid oxide fuel cells. This work further characterizes the nanocomposite SDC/Na2CO3 electrochemical properties and conduction mechanism. The microstructure of the nanocomposite sintered at different temperatures was analyzed through scanning electron microscope (SEM) and X-ray diffraction (XRD). The electrical and electrochemical properties were studied. Significant conductivity enhancement was observed in the H2 atmosphere compared with that of air atmosphere. The ratiocination of proton conduction rather than electronic conduction has been proposed consequently based on the observation of fuel cell performance. The fuel cell performance with peak power density of 375 mW cm(-2) at 550 degrees C has been achieved. A.C. impedance for the fuel cell under open circuit voltage (OCV) conditions illustrates the electrode polarization process is predominant in rate determination.

  7. Nonlinear modelling of polymer electrolyte membrane fuel cell stack using nonlinear cancellation technique

    International Nuclear Information System (INIS)

    Barus, R. P. P.; Tjokronegoro, H. A.; Leksono, E.; Ismunandar

    2014-01-01

    Fuel cells are promising new energy conversion devices that are friendly to the environment. A set of control systems are required in order to operate a fuel cell based power plant system optimally. For the purpose of control system design, an accurate fuel cell stack model in describing the dynamics of the real system is needed. Currently, linear model are widely used for fuel cell stack control purposes, but it has limitations in narrow operation range. While nonlinear models lead to nonlinear control implemnetation whos more complex and hard computing. In this research, nonlinear cancellation technique will be used to transform a nonlinear model into a linear form while maintaining the nonlinear characteristics. The transformation is done by replacing the input of the original model by a certain virtual input that has nonlinear relationship with the original input. Then the equality of the two models is tested by running a series of simulation. Input variation of H2, O2 and H2O as well as disturbance input I (current load) are studied by simulation. The error of comparison between the proposed model and the original nonlinear model are less than 1 %. Thus we can conclude that nonlinear cancellation technique can be used to represent fuel cell nonlinear model in a simple linear form while maintaining the nonlinear characteristics and therefore retain the wide operation range

  8. Quaternized poly(styrene ethylene butylene poly styrene)/multiwalled carbon nanotube composites for alkaline fuel cell applications.

    Science.gov (United States)

    Vinodh, Rajangam; Sangeetha, Dharmalingam

    2013-08-01

    The present study is aimed at synthesizing a novel anion exchange composite membrane from quaternized polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene [QPSEBS] and functionalized multi walled carbon nanotubes (f-MWCNT) by solution casting method. The characteristic properties of the QPSEBS/f-MWCNT composite membranes were investigated using Fourier transform infrared (FTIR), UV-Visible spectroscopy, thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD) studies and Raman spectroscopy. The water uptake, ion exchange capacity, ionic conductivity, methanol permeability and selectivity ratio of the membranes were also studied. The prepared composite membranes were tested in an in-house fabricated alkaline membrane fuel cell (AMFC) set up using Pt/C as the common anode catalyst and three different cathode catalysts namely Pt/C, Pd-Ni/C and Ag/C. Among all the three cathode catalysts, Pt/C for QPSEBS/5% f-MWCNT is found to show the maximum power density and open circuit voltage (OCV) of 187 mW cm(-2) and 0.73 V respectively. For direct methanol alkaline membrane fuel cells (DMAMFC), the OCV of QPSEBS/5% f-MWCNT is found to be 0.76 V and the maximum power density of 59.5 mW cm(-2) is achieved at a current density of 175 mA cm(-2).

  9. Nafion and modified-Nafion membranes for polymer electrolyte fuel

    Indian Academy of Sciences (India)

    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 ...

  10. In situ diagnostic of two-phase flow phenomena in polymer electrolyte fuel cells by neutron imaging

    International Nuclear Information System (INIS)

    Zhang Jianbo; Kramer, Denis; Shimoi, Ryoichi; Ono, Yoshitaka; Lehmann, Eberhard; Wokaun, Alexander; Shinohara, Kazuhiko; Scherer, Guenther G.

    2006-01-01

    The formation of liquid water in operating polymer electrolyte fuel cells (PEFC) of industrial and laboratory size has been investigated by in situ neutron imaging. The influence of the materials chosen for the structural components of the cell on droplet formation and transport in flow fields and on liquid formation in gas diffusion layers has been studied. The changing of the cathodic gas diffusion layer material allowed the relationship between materials, liquid accumulation, and electrochemical performance to be examined. It has been shown that material choice has considerable bearing on the presence of liquid inside the porous structures and the electrochemical characteristics. A simplified quasi one-dimensional cell with an active area of 25 cm 2 was used for materials comparison, and the results were related to technically relevant operating conditions - where inhomogeneities have to be considered - by subsequent examination of cells with an active area of 100 cm 2

  11. Temperature dependence of an abiotic glucose/air alkaline fuel cell

    Science.gov (United States)

    Orton, Dane; Scott, Daniel

    2015-11-01

    The temperature dependence of a previously developed glucose fuel cell is explored. This cell uses a small molecule dye mediator to transport oxidizable electrons from glucose to a carbon felt anode. This reaction is driven by an air breathing MnO2 cathode. This research investigates how the temperature of the system affects the power production of the fuel cell. Cell performance is observed using either methyl viologen, indigo carmine, trypan blue, or hydroquinone as a mediator at temperatures of 15, 19, 27, 32, 37, 42, and 49 °C. Cyclic voltammetry of the cell anode at the given temperatures with the individual dyes is also presented. The highest power production amongst all of the cells occurs at 32 °C. This occurs with the mediator indigo carmine or with the mediator methyl viologen. These sustained powers are 2.31 mW cm-2 and 2.39 mW cm-2, respectively. This is approximately a 350% increase for these cells compared to their power produced at room temperature. This dramatic increase is likely due to increased solubility of the mediator dye at higher temperatures.

  12. TiO2-nanowire/MWCNT composite with enhanced performance and durability for polymer electrolyte fuel cells

    Science.gov (United States)

    Selvaganesh, S. Vinod; Dhanasekaran, P.; Bhat, Santoshkumar D.

    2017-12-01

    Durability is a major issue and has been the growing focus of research for the commercialization of polymer electrolyte fuel cells (PEFCs). Corrosion of carbon support is a key parameter as it triggers the Pt catalyst degradation and affects cell performance, which in turn affects the longevity of the cells. Herein, we describe a hybrid composite support of TiO2-nanowires and Multiwalled carbon nanotubes (MWCNTs) that offers resistance to corrosion under stressful operating conditions. Titania nanowireswhich have been shown to be more efficient and catalytically active than spherically shaped TiO2. TiO2-MWCNT composites are prepared through a hydrothermal method, followed by Pt deposition using a polyol method. Crystal structure, morphology, and oxidation state are examined through various characterization techniques. Electrochemical performance of TiO2-nanowire/MWCNT composite-supported Pt at various ratios of TiO2/MWCNT is assessed in PEFCs. Pt on support with optimum composition of TiO2-nanowires to MWCNTs exhibits fuel cell performance superior to Pt onMWCNTs. Accelerated stress testing (AST) between 1 and 1.5 V reveals that the designed catalyst on nanocomposite support possesses superior electrochemical activity and shows only 16% loss in catalytic activity in relation to 35% for Pt/MWCNTs even after 6000 potential cycles. Subsequently, the samples were characterized after AST to correlate the loss in fuel cell performance

  13. Effects of grain boundaries at the electrolyte/cathode interfaces on oxygen reduction reaction kinetics of solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Min Gi; Koo, Ja Yang; Ahn, Min Woo; Lee, Won Young [Dept. of Mechanical Engineering, Sungkyunkwan University, Suwon (Korea, Republic of)

    2017-04-15

    We systematically investigated the effects of grain boundaries (GBs) at the electrolyte/cathode interface of two conventional electrolyte materials, i.e., yttria-stabilized zirconia (YSZ) and gadolinia-doped ceria (GDC). We deposited additional layers by pulsed laser deposition to control the GB density on top of the polycrystalline substrates, obtaining significant improvements in peak power density (two-fold for YSZ and three-fold for GDC). The enhanced performance at high GB density in the additional layer could be ascribed to the accumulation of oxygen vacancies, which are known to be more active sites for oxygen reduction reactions (ORR) than grain cores. GDC exhibited a higher enhancement than YSZ, due to the easier formation, and thus higher concentration, of oxygen vacancies for ORR. The strong relation between the concentration of oxygen vacancies and the surface exchange characteristics substantiated the role of GBs at electrolyte/cathode interfaces on ORR kinetics, providing new design parameters for highly performing solid oxide fuel cells.

  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. New electrolytes for direct methane fuel cells. Annual report, January 10, 1977-January 9, 1978. [Perhalogenated sulfonic acids

    Energy Technology Data Exchange (ETDEWEB)

    Brummer, S.B.; McHardy, J.; Koch, V.; Turner, M.; Toland, D.

    1978-01-01

    The program is aimed at developing a fuel cell electrolyte for the direct oxidation of CH/sub 4/ and/or impure H/sub 2/ fuels. Work in the first year has focused on the di- and tribasic methane sulfonic acids CX/sub 2/(SO/sub 3/H)/sub 2/ and CX(SO/sub 3/H)/sub 3/ where X was H, F, or Cl. Synthesis of the halogenated acids proved to be more difficult than anticipated, and only three acids, viz. CH(SO/sub 3/H)/sub 3/; CH/sub 2/(SO/sub 3/H)/sub 2/; CCl/sub 2/(SO/sub 3/H)/sub 2/ were prepared in sufficient quantity for electrochemical testing. However, promising synthetic routes have been identified for the other acids. Cyclic voltammetry was used to study the adsorption properties of the acids and half cell tests with gas diffusion electrodes were used to determine their suitability as fuel cell electrolytes. Results are presented and discussed. Also a program has been under way to develop low Pt loading (1 mg cm/sup -2/) fuel cell electrodes. The objective was to achieve control over the mass transfer parameters of an electrode so that optimum structures could be designed for use with the new electrolytes. In the interest of reproducibility, the experimental electrodes incorporated only well characterized materials; all forms of carbon were omitted. Optimum performance with H/sub 3/PO/sub 4/ was achieved with electrodes made as follows. One mg cm/sup -2/ Pt black and 1 mg cm/sup -2/ TFE 30 were mixed and filtered onto porous TFE tape. The tape was pressed into Au plated Ta screen sintered for 10 minutes at 340/sup 0/C. Current vs potential curves for both anodic reactions (CH/sub 4/ and H/sub 2/ oxidation) and cathodic reactions (O/sub 2/ and air reduction) were superior to the curves obtained with an American Cyanamid electrode containing 25 mg Pt cm/sup -2/. (WHK)

  16. Nanocarbon/oxide composite catalysts for bifunctional oxygen reduction and evolution in reversible alkaline fuel cells: A mini review

    Science.gov (United States)

    Chen, Mengjie; Wang, Lei; Yang, Haipeng; Zhao, Shuai; Xu, Hui; Wu, Gang

    2018-01-01

    A reversible fuel cell (RFC), which integrates a fuel cell with an electrolyzer, is similar to a rechargeable battery. This technology lies on high-performance bifunctional catalysts for the oxygen reduction reaction (ORR) in the fuel cell mode and the oxygen evolution reaction (OER) in the electrolyzer mode. Current catalysts are platinum group metals (PGM) such as Pt and Ir, which are expensive and scarce. Therefore, it is highly desirable to develop PGM-free catalysts for large-scale application of RFCs. In this mini review, we discussed the most promising nanocarbon/oxide composite catalysts for ORR/OER bifunctional catalysis in alkaline media, which is mainly based on our recent progress. Starting with the effectiveness of selected oxides and nanocarbons in terms of their activity and stability, we outlined synthetic methods and the resulting structures and morphologies of catalysts to provide a correlation between synthesis, structure, and property. A special emphasis is put on understanding of the possible synergistic effect between oxide and nanocarbon for enhanced performance. Finally, a few nanocomposite catalysts are discussed as typical examples to elucidate the rules of designing highly active and durable bifunctional catalysts for RFC applications.

  17. Acid-doped Polybenzimidazole Membranes as Electrolyte for Fuel Cells Operating Above 100°C

    DEFF Research Database (Denmark)

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

    2003-01-01

    humidification and high CO-tolerance up to 10 vol%. This high CO tolerance allows for a direct use of reformed hydrogen without further CO removal, which opens the possibility for an integrated reformer-fuel cell system. The content of this review is to a large extent based on research performed by the authors...

  18. New polymeric electrolyte membranes based on proton donor proton acceptor properties for direct methanol fuel cells

    NARCIS (Netherlands)

    Manea, G.C.; Mulder, M.H.V.

    2002-01-01

    In order to reduce the high methanol permeability of membranes in a direct methanol fuel cell application new and better materials are still required. In this paper membranes made from polybenzimidazole/sulfonated polysulfone are given and compared with homopolymer membranes made from sulfonated

  19. A Quaternary Polybenzimidazole Membrane for Intermediate Temperature Polymer Electrolyte Membrane Fuel Cells

    DEFF Research Database (Denmark)

    Xu, C.; Scott, K.; Li, Qingfeng

    2013-01-01

    A quaternary ammonium polybenzimidazole (QPBI) membrane was synthesized for applications in intermediate temperature (100–200 °C) hydrogen fuel cells. The QPBI membrane was imbibed with phosphoric acid to provide suitable proton conductivity. The proton conductivity of the membrane was 0.051 S cm–1...

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

    DEFF Research Database (Denmark)

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

    2011-01-01

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

  1. Amino-Functional Polybenzimidazole Blends with Enhanced Phosphoric Acid Mediated Proton Conductivity as Fuel Cell Electrolytes

    DEFF Research Database (Denmark)

    Aili, David; Javakhishvili, Irakli; Han, Junyoung

    2016-01-01

    A new amino-functional polybenzimidazole copolymer is synthesized by homogeneous solution condensation polymerization from a novel monomer, N,N′-bis (2,4-diaminophenyl)-1,3-diaminopropane. The copolymer readily dissolves in organic solvents and shows good film forming characteristics. To balance ...... conductivity at temperatures well above 100 °C as also confirmed by the fuel cell polarization data....

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

    DEFF Research Database (Denmark)

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

    2011-01-01

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

  3. 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

    , compared to less than 100 ppm CO for the Nafion-based technology at 80degrees C. The high CO tolerance makes it possible to use the reformed hydrogen directly from a simple methanol reformer without further CO removal. That both the fuel cell and the methanol reformer operate at temperatures around 200...

  4. Alkaline-Acid Zn-H2 O Fuel Cell for the Simultaneous Generation of Hydrogen and Electricity.

    Science.gov (United States)

    Cai, Pingwei; Li, Yan; Wang, Genxiang; Wen, Zhenhai

    2018-04-03

    An alkaline-acid Zn-H 2 O fuel cell is proposed for the simultaneous generation of electricity with an open circuit voltage of about 1.25 V and production of H 2 with almost 100 % Faradic efficiency. We demonstrate that, as a result of harvesting energy from both electrochemical neutralization and electrochemical Zn oxidation, the as-developed hybrid cell can deliver a power density of up to 80 mW cm -2 and an energy density of 934 Wh kg -1 and maintain long-term stability for H 2 production with an output voltage of 1.16 V at a current density of 10 mA cm -2 . © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. FY 1999 Report on research and development of power generation by solid electrolyte fuel cell. Research and development of solid electrolyte fuel cell; 1999 nendo nenryo denchi hatsuden gijutsu kaihatsu kotai denkaishitsugata nenryo denchi no kenkyu kaihatsu kenkyu seika

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-06-01

    This project is aimed at establishment of the module basic technology and commercialization of the solid electrolyte fuel cell in the early stage by designing, construction, operation and performance evaluation of a several kW-class module which incorporates the cylindrical cell fabricated by the wet process. The FY 1999 R and D efforts include (1) cell performance demonstration study: the cylindrical single cell fabricated by the wet process is demonstration-tested to determine the initial performance and durability for continuous operation, thereby comparing the external reforming with internal reforming in output, with the internal reforming rate as the parameter, (2) development of a several kW-class module: the adequate cell arrangement structure within the module is studied by the computer-aided simulation, and the tests for confirming thermal cycle durability of the modified bundle are conducted using the module power generation unit and the several kW-class module is tested, and (3) development of the technology for designing a thermally supported module: the effects of, e.g., air and fuel supply conditions on the module performance are analyzed using the analytical model as the base. Expansion of the module level to the process simulation model has been completed, based on these results. (NEDO)

  6. Development and Application of a Sample Holder for In Situ Gaseous TEM Studies of Membrane Electrode Assemblies for Polymer Electrolyte Fuel Cells.

    Science.gov (United States)

    Kamino, Takeo; Yaguchi, Toshie; Shimizu, Takahiro

    2017-10-01

    Polymer electrolyte fuel cells hold great potential for stationary and mobile applications due to high power density and low operating temperature. However, the structural changes during electrochemical reactions are not well understood. In this article, we detail the development of the sample holder equipped with gas injectors and electric conductors and its application to a membrane electrode assembly of a polymer electrolyte fuel cell. Hydrogen and oxygen gases were simultaneously sprayed on the surfaces of the anode and cathode catalysts of the membrane electrode assembly sample, respectively, and observation of the structural changes in the catalysts were simultaneously carried out along with measurement of the generated voltages.

  7. Record-low sintering-temperature (600 °C) of solid-oxide fuel cell electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Dasari, Hari Prasad, E-mail: energyhari@nitk.edu.in [High-Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Chemical Engineering Department, National Institute of Technology Karnataka, Mangalore 575025, Karnataka (India); Ahn, Kiyong; Park, Sun-Young; Hong, Jongsup; Kim, Hyoungchul; Yoon, Kyung Joong; Son, Ji-Won; Kim, Byung-Kook; Lee, Hae-Weon [High-Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Lee, Jong-Ho, E-mail: jongho@kist.re.kr [High-Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of)

    2016-07-05

    One of the major problems arising with Solid-Oxide Fuel Cell (SOFC) electrolyte is conventional sintering which requires a very high temperature (>1300 °C) to fully density the electrolyte material. In the present study, the sintering temperature of SOFC electrolyte is drastically decreased down to 600 °C. Combinational effects of particle size reduction, liquid-phase sintering mechanism and microwave sintering resulted in achieving full density in such a record-low sintering temperature. Gadolinium doped Ceria (GDC) nano-particles are synthesized by co-precipitation method, Lithium (Li), as an additional dopant, is used as liquid-phase sintering aid. Microwave sintering of this electrolyte material resulted in decreasing the sintering temperature to 600 °C. Micrographs obtained from Scanning/Transmission Electron Microscopy (SEM/TEM) clearly pointed a drastic growth in grain-size of Li-GDC sample (∼150 nm) than compared to GDC sample (<30 nm) showing the significance of Li addition. The sintered Li-GDC samples displayed an ionic conductivity of ∼1.00 × 10{sup −2} S cm{sup −1} at 600 °C in air and from the conductivity plots the activation energy is found to be 0.53 eV. - Highlights: • Sintering temperature is drastically decreased to 600 °C. • Key factors: Particle size reduction, liquid-phase and microwave sintering. • Nano-Li-GDC sample has ionic conductivity of ∼1.00 × 10{sup −2} S cm{sup −1} at 600 °C in air.

  8. Limitations of Commercializing Fuel Cell Technologies

    Science.gov (United States)

    Nordin, Normayati

    2010-06-01

    Fuel cell is the technology that, nowadays, is deemed having a great potential to be used in supplying energy. Basically, fuel cells can be categorized particularly by the kind of employed electrolyte. Several fuel cells types which are currently identified having huge potential to be utilized, namely, Solid Oxide Fuel Cells (SOFC), Molten Carbonate Fuel Cells (MCFC), Alkaline Fuel Cells (AFC), Phosphoric Acid Fuel Cells (PAFC), Polymer Electron Membrane Fuel Cell (PEMFC), Direct Methanol Fuel Cells (DMFC) and Regenerative Fuel Cells (RFC). In general, each of these fuel cells types has their own characteristics and specifications which assign the capability and suitability of them to be utilized for any particular applications. Stationary power generations and transport applications are the two most significant applications currently aimed for the fuel cell market. It is generally accepted that there are lots of advantages if fuel cells can be excessively commercialized primarily in context of environmental concerns and energy security. Nevertheless, this is a demanding task to be accomplished, as there is some gap in fuel cells technology itself which needs a major enhancement. It can be concluded, from the previous study, cost, durability and performance are identified as the main limitations to be firstly overcome in enabling fuel cells technology become viable for the market.

  9. 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.

  10. Effects of heat and water transport on the performance of polymer electrolyte membrane fuel cell under high current density operation

    International Nuclear Information System (INIS)

    Tabuchi, Yuichiro; Shiomi, Takeshi; Aoki, Osamu; Kubo, Norio; Shinohara, Kazuhiko

    2010-01-01

    Key challenges to the acceptance of polymer electrolyte membrane fuel cells (PEMFCs) for automobiles are the cost reduction and improvement in its power density for compactness. In order to get the solution, the further improvement in a fuel cell performance is required. In particular, under higher current density operation, water and heat transport in PEMFCs has considerable effects on the cell performance. In this study, the impact of heat and water transport on the cell performance under high current density was investigated by experimental evaluation of liquid water distribution and numerical validation. Liquid water distribution in MEA between rib and channel area is evaluated by neutron radiography. In order to neglect the effect of liquid water in gas channels and reactant species concentration distribution in the flow direction, the differential cell was used in this study. Experimental results suggested that liquid water under the channel was dramatically changed with rib/channel width. From the numerical study, it is found that the change of liquid water distribution was significantly affected by temperature distribution in MEA between rib and channel area. In addition, not only heat transport but also water transport through the membrane also significantly affected the cell performance under high current density operation.

  11. Novel composite membranes based on PBI and dicationic ionic liquids for high temperature polymer electrolyte membrane fuel cells

    International Nuclear Information System (INIS)

    Hooshyari, Khadijeh; Javanbakht, Mehran; Adibi, Mina

    2016-01-01

    Two types of innovative composite membranes based on polybenzimidazole (PBI) containing dicationic ionic liquid 1,3-di(3-methylimidazolium) propane bis (trifluoromethylsulfonyl) imide (PDC 3 ) and monocationic ionic liquid 1-hexyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide (PMC 6 ) are prepared as electrolyte for high temperature fuel cells applications under anhydrous conditions. The analyses of results display promising characteristics such as high proton conductivity and thermal stability. Moreover the fuel cell performance of PA doped PDC 3 composite membranes is enhanced in comparison with PA doped PMC 6 and PA doped PBI membranes at high temperatures. Dicationic ionic liquid with high number of charge carriers provides well-developed ionic channels which form facile pathways and considerably develop the anhydrous proton conductivity. The highest proton conductivity of 81 mS/cm is achieved for PA doped PDC 3 composite membranes with PBI/IL mole ratio: 4 at 180 °C. A power density of 0.44 W/cm 2 is obtained at 0.5 V and 180 °C for PA doped PDC 3 composite membranes, which proves that these developed composite membranes can be considered as most promising candidates for high temperature fuel cell applications with enhanced proton conductivity.

  12. A mathematical model for predicting the life of polymer electrolyte fuel cell membranes subjected to hydration cycling

    Science.gov (United States)

    Burlatsky, S. F.; Gummalla, M.; O'Neill, J.; Atrazhev, V. V.; Varyukhin, A. N.; Dmitriev, D. V.; Erikhman, N. S.

    2012-10-01

    Under typical Polymer Electrolyte Membrane Fuel Cell (PEMFC) fuel cell operating conditions, part of the membrane electrode assembly is subjected to humidity cycling due to variation of inlet gas RH and/or flow rate. Cyclic membrane hydration/dehydration would cause cyclic swelling/shrinking of the unconstrained membrane. In a constrained membrane, it causes cyclic stress resulting in mechanical failure in the area adjacent to the gas inlet. A mathematical modeling framework for prediction of the lifetime of a PEMFC membrane subjected to hydration cycling is developed in this paper. The model predicts membrane lifetime as a function of RH cycling amplitude and membrane mechanical properties. The modeling framework consists of three model components: a fuel cell RH distribution model, a hydration/dehydration induced stress model that predicts stress distribution in the membrane, and a damage accrual model that predicts membrane lifetime. Short descriptions of the model components along with overall framework are presented in the paper. The model was used for lifetime prediction of a GORE-SELECT membrane.

  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. Nanographene synthesized in triple-phase plasmas as a highly durable support of catalysts for polymer electrolyte fuel cells

    Science.gov (United States)

    Amano, Tomoki; Kondo, Hiroki; Takeda, Keigo; Ishikawa, Kenji; Hiramatsu, Mineo; Sekine, Makoto; Hori, Masaru

    2018-04-01

    Nanographene was synthesized in triple-phase plasmas comprising a gaseous phase, a gas-liquid boundary layer, and an in-liquid phase using a setup in which one electrode was placed in the gaseous phase while the other was immersed in the liquid phase. The triple-phase plasmas were generated using a pure alcohol, such as ethanol, 1-propanol, or 1-butanol, by applying a high voltage to a pair of electrodes made of copper or graphite. The nanographene synthesized using ethanol had high durability and thus could serve as a catalyst support in polymer electrolyte fuel cells (PEFCs). The PEFCs exhibited low degradation rates in the high-potential cycle test of a half-cell, as a result of which, a loss of only 10% was observed in the effective electrochemical surface area of Pt, even after 10,000 cycles.

  15. Mechanistic equivalent circuit modelling of a commercial polymer electrolyte membrane fuel cell

    Science.gov (United States)

    Giner-Sanz, J. J.; Ortega, E. M.; Pérez-Herranz, V.

    2018-03-01

    Electrochemical impedance spectroscopy (EIS) has been widely used in the fuel cell field since it allows deconvolving the different physic-chemical processes that affect the fuel cell performance. Typically, EIS spectra are modelled using electric equivalent circuits. In this work, EIS spectra of an individual cell of a commercial PEM fuel cell stack were obtained experimentally. The goal was to obtain a mechanistic electric equivalent circuit in order to model the experimental EIS spectra. A mechanistic electric equivalent circuit is a semiempirical modelling technique which is based on obtaining an equivalent circuit that does not only correctly fit the experimental spectra, but which elements have a mechanistic physical meaning. In order to obtain the aforementioned electric equivalent circuit, 12 different models with defined physical meanings were proposed. These equivalent circuits were fitted to the obtained EIS spectra. A 2 step selection process was performed. In the first step, a group of 4 circuits were preselected out of the initial list of 12, based on general fitting indicators as the determination coefficient and the fitted parameter uncertainty. In the second step, one of the 4 preselected circuits was selected on account of the consistency of the fitted parameter values with the physical meaning of each parameter.

  16. Elaboration and study of fuel cell according to solid polymer electrolyte technology

    Energy Technology Data Exchange (ETDEWEB)

    Novel-Cattin, F.

    1990-10-23

    A hydrogen-oxygen fuel cell was built in an attempt to develop a pilot scale fuel cell of a few kW. These fuel cells were based on a polymeric ion exchange membrane commercialized by Dupont de Nemours under the trademark NAFION 117. This work consists in part of the development of different test cells, for electrodes of surface area from 1 to 25 cm{sup 2}. Different types of porous electrodes were also used containing platinum as the electro-catalyst, in the synthesis of composite electrode-membrane electrode ensembles. Different methods of electrode manufacture are detailed in this thesis. These electrodes were characterized by their current potential behaviour under stationary conditions. Different analysis technics, such as the microprobe and electronic microscopy were used. The electrode structure was studied using impedance spectroscopy. A full factorial optimization program was developed in order to optimize the performance of some of these electrodes. The use of the thermoplastic form of the membrane was used as a mean of incorporating the electrodes into the membrane. The transport of water coupled to proton migration across the membrane was also measured. (author). 82 refs., 32 figs., 10 tabs., 11 curves., 14 schemes., 2 appends.

  17. Pyrolysis result of polyethylene waste as fuel for solid oxide fuel cell with samarium doped-ceria (SDC)-carbonate as electrolyte

    Science.gov (United States)

    Syahputra, R. J. E.; Rahmawati, F.; Prameswari, A. P.; Saktian, R.

    2017-02-01

    In this research, the result of pyrolysis on polyethylene was used as fuel for a solid oxide fuel cell (SOFC). The pyrolysis result is a liquid which consists of hydrocarbon chains. According to GC-MS analysis, the hydrocarbons mainly consist of C7 to C20 hydrocarbon chain. Then, the liquid was applied to a single cell of NSDC-L | NSDC | NSDC-L. NSDC is a composite SDC (samarium doped-ceria) with sodium carbonate. Meanwhile, NSDC-L is a composite of NSDC with LiNiCuO (LNC). NSDC and LNC were analyzed by X-ray diffraction to understand their crystal structure. The result shows that presence of carbonate did not change the crystal structure of SDC. SEM EDX analysis for fuel cell before and after being loaded with polyethylene oil to get information of element diffusion to the electrolyte. Meanwhile, the conductivity properties were investigated through impedance measurement. The presence of carbonate even increases the electrical conductivity. The single cell test with the pyrolysis result of polyethylene at 300 - 600 °C, found that the highest power density is at 600 °C with the maximum power density of 0.14 mW/cm2 and open circuit voltage of 0.4 Volt. Elemental analysis at three point spots of single cell NDSC-L |NSDC|NSDC-L found that a migration of ions was occurred during fuel operation at 300 - 600 °C.

  18. Binderless electrodes for high-temperature polymer electrolyte membrane fuel cells

    DEFF Research Database (Denmark)

    Fernandez, Santiago Martin; Li, Qingfeng; Steenberg, Thomas

    2014-01-01

    A new electrode concept was proved with no polymeric binder in the catalyst layer for acid-doped polybenzimidazole (PBI) membrane fuel cells. It shows that a stable interface between the membrane and the catalyst layer can be retained when a proton conducting acid phase is established. The absence...... higher than 0.5 mgPt cm−2. For fuel cell operation on H2 and air supplied under ambient pressure, a peak power density as high as 471 mW cm−2 was measured. The tolerance to carbon monoxide (CO) was also studied with Pt loadings of the anode ranging from 0.24 to 1.82 mgPt cm−2. Lifetime test for a MEA...... loaded with 0.96 mgPt cm−2 on both electrodes revealed no voltage decay during 900 h of uninterrupted operation at 200 mA cm−2 and 160 °C....

  19. Polybenzimidazole Membranes Containing Benzimidazole Side Groups for High Temprature Polymer Electrolyte Membrane Fuel Cells

    DEFF Research Database (Denmark)

    Yang, Jingshuai; Li, Xueyuan; Xu, Yizin

    2013-01-01

    temperatures without humidification. At an acid doping level of 13.1 mol H3PO4 per average molar repeat unit, the PBI membranes with a benzimidazole grafting degree of 10.6% demonstrated a conductivity of 0.15 S cm-1 and a H2-air fuel cell peak power density of 378 mW cm-2 at 180 oC at ambient pressure without...

  20. Water Uptake and Acid Doping of Polybenzimidazoles as Electrolyte Membranes for Fuel Cells

    DEFF Research Database (Denmark)

    Qingfeng, Li; He, R.; Berg, Rolf W.

    2004-01-01

    Acid-doped polybenzimidazole (PBI) membranes have been demonstrated for fuel cell applications with advanced features such as high operating temperatures, little humidification, excellent CO tolerance, and promising durability. The water uptake and acid doping of PBI membranes have been studied. ...... of the imidazole rings. The excessive doping acid is "free acid" that contributes to high conductivity but suffers from a fast washing out when adequate liquid is present. (C) 2004 Elsevier B.V. All rights reserved....

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

    DEFF Research Database (Denmark)

    Søndergaard, Stine; Cleemann, Lars Nilausen; Jensen, Jens Oluf

    2017-01-01

    This paper describes the results of adding small amounts of CO gas to the cathode side in a HT-PEM fuel cell with a polybenzimidazole (PBI) membrane running on either oxygen or air. Experimental conditions: Temperature ranges 120–160 °C, constant current either 200 mA/cm2 or 800 mA/cm2 and CO...

  2. Oxygen electrodes for ceramic fuel cells with proton and oxide ion conducting electrolytes

    OpenAIRE

    Strandbakke, Ragnar

    2014-01-01

    The overall aim of this work is to contribute to a better understanding of the reactions taking place at the oxygen electrode in proton ceramic fuel cells (PCFCs) and, moreover, to develop new materials with improved performance for this electrode. PCFCs and their cathode reactions are the main focus of the study, but these reactions are often running in parallel with reactions associated with other charge carriers that also need to be addressed. Most proton conducting ceramics exhibit also t...

  3. Parametric Sensitivity Tests—European Polymer Electrolyte Membrane Fuel Cell Stack Test Procedures

    DEFF Research Database (Denmark)

    Araya, Samuel Simon; Andreasen, Søren Juhl; Kær, Søren Knudsen

    2014-01-01

    performed based on test procedures proposed by a European project, Stack-Test. The sensitivity of a Nafion-based low temperature PEMFC stack’s performance to parametric changes was the main objective of the tests. Four crucial parameters for fuel cell operation were chosen; relative humidity, temperature......, pressure, and stoichiometry at varying current density. Furthermore, procedures for polarization curve recording were also tested both in ascending and descending current directions....

  4. Potential Usage of Thermoelectric Devices in a High-Temperature Polymer Electrolyte Membrane (PEM) Fuel Cell System: Two Case Studies

    Science.gov (United States)

    Gao, Xin; Chen, Min; Andreasen, Søren Juhl; Kær, Søren Knudsen

    2012-06-01

    Methanol-fueled, high-temperature polymer electrolyte membrane fuel cell (HTPEMFC) power systems are promising as the next generation of vehicle engines, efficient and environmentally friendly. Currently, their performance still needs to be improved, and they still rely on a large Li-ion battery for system startup. In this article, to handle these two issues, the potential of thermoelectric (TE) devices applied in a HTPEMFC power system has been preliminarily evaluated. First, right after the fuel cell stack or the methanol reformer, thermoelectric generators (TEGs) are embedded inside a gas-liquid heat exchanger to form a heat recovery subsystem jointly for electricity production. It is calculated that the recovered power can increase the system efficiency and mitigate the dependence on Li-ion battery during system startup. To improve the TEG subsystem performance, a finite-difference model is then employed and two main parameters are identified. Second, TE coolers are integrated into the methanol steam reformer to regulate heat fluxes herein and improve the system dynamic performance. Similar modification is also done on the evaporator to improve its dynamic performance as well as to reduce the heat loss during system startup. The results demonstrate that the TE-assisted heat flux regulation and heat-loss reduction can also effectively help solve the abovementioned two issues. The preliminary analysis in this article shows that a TE device application inside HTPEMFC power systems is of great value and worthy of further study.

  5. Environmental and economic assessment of a cracked ammonia fuelled alkaline fuel cell for off-grid power applications

    Science.gov (United States)

    Cox, Brian; Treyer, Karin

    2015-02-01

    Global mobile telecommunication is possible due to millions of Base Transceiver Stations (BTS). Nearly 1 million of these are operating off-grid, typically powered by diesel generators and therefore leading to significant CO2 emissions and other environmental burdens. A novel type of Alkaline Fuel Cell (AFC) powered by cracked ammonia is being developed for replacement of these generators. This study compares the environmental and economic performance of the two systems by means of Life Cycle Assessment (LCA) and Levelised Cost of Electricity (LCOE), respectively. Results show that the production of ammonia dominates the LCA results, and that renewable ammonia production pathways greatly improve environmental performance. Sensitivity analyses reveal that the fuel cell parameters that most affect system cost and environmental burdens are cell power density and lifetime and system efficiency. Recycling of anode catalyst and electrode substrate materials is found to have large impacts on environmental performance, though without large cost incentives. For a set of target parameter values and fossil sourced ammonia, the AFC is calculated to produce electricity with life cycle CO2 eq emissions of 1.08 kg kWh-1, which is 23% lower than a diesel generator with electricity costs that are 14% higher in the same application.

  6. Production of ceramic layers on aluminum alloys by plasma electrolytic oxidation in alkaline silicate electrolytes

    Science.gov (United States)

    Lugovskoy, Alex; Zinigrad, Michael; Kossenko, Aleksey; Kazanski, Barbara

    2013-01-01

    Plasma electrolytic oxidation (PEO) of aluminum alloy 5052 in alkaline-silicate electrolytes having different SiO2/Na2O ratios (silicate indexes) was studied. For all the electrolytes 20-90 μm thick technological layer was obtained; composition, structure and properties of the oxidized layer were studied. For each sample, the oxidized layer consists of a denser internal and looser external sublayer. While for “n = 1 electrolytes” the oxidized layer is mainly formed by several kinds of alumina, the principal constituent of the oxidized layer for “n = 3 electrolytes” is mullite. Measurements of microhardness evidenced that it is apparently not influenced by the kind of silicate (n = 1 or n = 3) and by its concentration in the electrolyte. Electrolytes with silicate index n = 3 ensure better corrosion protection than those with n = 1. Corrosion protection parameters are significantly better for all PEO oxidized samples than for the untreated Al5052 alloy.

  7. High performance nano-Ni/Graphite electrode for electro-oxidation in direct alkaline ethanol fuel cells

    Science.gov (United States)

    Soliman, Ahmed B.; Abdel-Samad, Hesham S.; Abdel Rehim, Sayed S.; Ahmed, Mohamed A.; Hassan, Hamdy H.

    2016-09-01

    Ni/Graphite electrocatalysts (Ni/G) are successfully prepared through electrodeposition of Ni from acidic (pH = 0.8) and feebly acidic (pH = 5.5) aqueous Ni (II) baths. The efficiencies of such electrodes are investigated as anodes for direct alkaline ethanol fuel cells through their ethanol electrooxidation cyclic voltammetric (CV) response in alkaline medium. A direct proportionality between the amount of the electrodeposited Ni and its CV response is found. The amounts of the deposited Ni from the two baths are recorded using the Electrochemical Quartz Crystal Microbalance (eQCM). The Ni/G electrodes prepared from the feebly acidic bath show a higher electrocatalytic response than those prepared from the acidic bath. Surface morphology of the Ni particles electrodeposited from feebly acidic bath appears in a nano-scale dimension. Various electrochemical experiments are conducted to confirm that the Ni/G ethanol electrooxidation CV response greatly depends on the pH rather than nickel ion concentration of the deposition bath. The eQCM technique is used to detect the crystalline phases of nickel as α-Ni(OH)2/γ-NiOOH and β-Ni(OH)2/β-NiOOH and their in-situ inter-transformations during the potentiodynamic polarization.

  8. Alkaline earth metal and samarium co-doped ceria as efficient electrolytes

    Science.gov (United States)

    Ali, Amjad; Raza, Rizwan; Kaleem Ullah, M.; Rafique, Asia; Wang, Baoyuan; Zhu, Bin

    2018-01-01

    Co-doped ceramic electrolytes M0.1Sm0.1Ce0.8O2-δ (M = Ba, Ca, Mg, and Sr) were synthesized via co-precipitation. The focus of this study was to highlight the effects of alkaline earth metals in doped ceria on the microstructure, densification, conductivity, and performance. The ionic conductivity comparisons of prepared electrolytes in the air atmosphere were studied. It has been observed that Ca0.1Sm0.1Ce0.8O2-δ shows the highest conductivity of 0.124 Scm-1 at 650 °C and a lower activation energy of 0.48 eV. The cell shows a maximum power density of 630 mW cm-2 at 650 °C using hydrogen fuel. The enhancement in conductivity and performance was due to increasing the oxygen vacancies in the ceria lattice with the increasing dopant concentration. The bandgap was calculated from UV-Vis data, which shows a red shift when compared with pure ceria. The average crystallite size is in the range of 37-49 nm. DFT was used to analyze the co-doping structure, and the calculated lattice parameter was compared with the experimental lattice parameter.

  9. Effect of short-term alkaline intervention on the performance of buffer-free single-chamber microbial fuel cell.

    Science.gov (United States)

    Yang, Na; Ren, Yueping; Li, Xiufen; Wang, Xinhua

    2017-06-01

    Anolyte acidification is a drawback restricting the electricity generation performance of the buffer-free microbial fuel cells (MFC). In this paper, a small amount of alkali-treated anion exchange resin (AER) was placed in front of the anode in the KCl mediated single-chamber MFC to slowly release hydroxyl ions (OH - ) and neutralize the H + ions that are generated by the anodic reaction in two running cycles. This short-term alkaline intervention to the KCl anolyte has promoted the proliferation of electroactive Geobacter sp. and enhanced the self-buffering capacity of the KCl-AER-MFC. The pH of the KCl anolyte in the KCl-AER-MFC increased and became more stable in each running cycle compared with that of the KCl-MFC after the short-term alkaline intervention. The maximum power density (P max ) of the KCl-AER-MFC increased from 307.5mW·m -2 to 542.8mW·m -2 , slightly lower than that of the PBS-MFC (640.7mW·m -2 ). The coulombic efficiency (CE) of the KCl-AER-MFC increased from 54.1% to 61.2% which is already very close to that of the PBS-MFC (61.9%). The results in this paper indicate that short-term alkaline intervention to the anolyte is an effective strategy to further promote the performance of buffer-free MFCs. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. 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.

  11. 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.

  12. 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)

  13. Novel synthesis of highly durable and active Pt catalyst encapsulated in nitrogen containing carbon for polymer electrolyte membrane fuel cell

    Science.gov (United States)

    Lee, Hyunjoon; Sung, Yung-Eun; Choi, Insoo; Lim, Taeho; Kwon, Oh Joong

    2017-09-01

    Novel synthesis of a Pt catalyst encapsulated in a N-containing carbon layer for use in a polymer electrolyte membrane fuel cell is described in this study. A Pt-aniline complex, formed by mixing Pt precursor and aniline monomer, was used as the source of Pt, C, and N. Heat treatment of the Pt-aniline complex with carbon black yielded 5 nm Pt nanoparticles encapsulated by a N-containing carbon layer originating from aniline carbonization. The synthesized Pt catalyst exhibited higher mass specific activity to oxygen reduction reaction than that shown by conventional Pt/C catalyst because pyridinic N with graphitic carbon in the carbon layer provided active sites for oxygen reduction reaction in addition to those provided by Pt. In single cell testing, initial performance of the synthesized catalyst was limited because the thick catalyst layer increased resistance related to mass transfer. However, it was observed that the carbon layer successfully prevented Pt nanoparticles from growing via agglomeration and Ostwald ripening under fuel cell operation, thereby improving durability. Furthermore, a mass specific performance of the synthesized catalyst higher than that of a conventional Pt/C catalyst was achieved by modifying the synthesized catalyst's layer thickness.

  14. Comprehensive one-dimensional, semi-analytical, mathematical model for liquid-feed polymer electrolyte membrane direct methanol fuel cells

    Science.gov (United States)

    Kareemulla, D.; Jayanti, S.

    Polymer electrolyte membrane direct methanol fuel cells (PEM-DMFCs) have several advantages over hydrogen-fuelled PEM fuel cells; but sluggish methanol electrochemical oxidation and methanol crossover from the anode to the cathode through the PEM are two major problems with these cells. In the present work, a comprehensive one-dimensional, single phase, isothermal mathematical model is developed for a liquid-feed PEM-DMFC, taking into account all the necessary mass transport and electrochemical phenomena. Diffusion and convective effects are considered for methanol transport on the anode side and in the PEM, whereas only diffusional transport of species is considered on the cathode side. A multi-step reaction mechanism is used to describe the electrochemical oxidation of methanol at the anode. Stefan-Maxwell equations are used to describe multi-component diffusion on the cathode side and Tafel type of kinetics is used to describe the simultaneous methanol oxidation and oxygen reduction reactions at the cathode. The model fully accounts for the mixed potential effect caused by methanol crossover at the cathode. It shows excellent agreement with literature data of the limiting current density for different low methanol feed concentrations at different operating temperatures. At high methanol feed concentrations, oxygen depletion on the cathode side, due to excessive methanol crossover, results in mass-transport limitations. The model can be used to optimize the geometric and physical parameters with a view to extracting the highest current density while still keeping a tolerably low methanol crossover.

  15. 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 contact resistance measurements. Upon anodization the contact resistances remained unchanged....

  16. Pore-Network Modeling of Water and Vapor Transport in the Micro Porous Layer and Gas Diffusion Layer of a Polymer Electrolyte Fuel Cell

    NARCIS (Netherlands)

    Qin, C.; Hassanizadeh, S.M.; van Oosterhout, L.M.

    2016-01-01

    In the cathode side of a polymer electrolyte fuel cell (PEFC), a micro porous layer (MPL) added between the catalyst layer (CL) and the gas diffusion layer (GDL) plays an important role in water management. In this work, by using both quasi-static and dynamic pore-network models, water and vapor

  17. Transpassive electrodissolution of depleted uranium in alkaline electrolytes

    International Nuclear Information System (INIS)

    Weisbrod, K.R.; Schake, A.R.; Morgan, A.N.; Purdy, G.M.; Martinez, H.E.; Nelson, T.O.

    1998-03-01

    To aid in removal of oralloy from the nuclear weapons stockpile, scientists at the Los Alamos National Laboratory Plutonium Facility are decontaminating oralloy parts by electrodissolution in neutral to alkaline electrolytes composed of sodium nitrate and sodium sulfate. To improve the process, electrodissolution experiments were performed with depleted uranium to understand the effects of various operating parameters. Sufficient precipitate was also produced to evaluate the feasibility of using ultrafiltration to separate the uranium oxide precipitates from the electrolyte before it enters the decontamination fixture. In preparation for the experiments, a potential-pH diagram for uranium was constructed from thermodynamic data for fully hydrated species. Electrodissolution in unstirred solutions showed that uranium dissolution forms two layers, an acidic bottom layer rich in uranium and an alkaline upper layer. Under stirred conditions results are consistent with the formation of a yellow precipitate of composition UO 3 ·2H 2 O, a six electron process. Amperometric experiments showed that current efficiency remained near 100% over a wide range of electrolytes, electrolyte concentrations, pH, and stirring conditions

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

    DEFF Research Database (Denmark)

    Jensen, Jens Oluf; Li, Qingfeng

    voltage around 0.6 V. The target durability is more than 5,000 hours. A hydrocarbon reformer and a 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......, and 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...

  19. Lifetime Estimation of Electrolytic Capacitors in Fuel Cell Power Converter at Various Confidence Levels

    DEFF Research Database (Denmark)

    Zhou, Dao; Wang, Huai; Blaabjerg, Frede

    2016-01-01

    based lifetime expectancy of the individual capacitor and the capacitor bank is estimated in a fuel cell backup power converter operating in both standby mode and operation mode. The lifetime prediction of the capacitor banks at different confidence levels is also obtained.......DC capacitors in power electronic converters are a major constraint on improvement of the power density and the reliability. In this paper, according to the degradation data of tested capacitors, the lifetime model of the component is analyzed at various confidence levels. Then, the mission profile...

  20. Scholarly Research Program. Delivery Order 0007: Characterization of Ionic Liquids as Fuel Cell Electrolytes

    National Research Council Canada - National Science Library

    Keitz, Thomas L; Katovic, Vladimir; Davidson, Amanda

    2004-01-01

    The object of this work was to synthesize the room temperature ionic liquids, EMImBF4, BMImBF4 and BMPBETI, and to study the electrochemical behavior of ethanol in these electrolytes on the Pt electrode...

  1. Fuel Cell Handbook, Fifth Edition

    Energy Technology Data Exchange (ETDEWEB)

    Energy and Environmental Solutions

    2000-10-31

    Progress continues in fuel cell technology since the previous edition of the Fuel Cell Handbook was published in November 1998. Uppermost, polymer electrolyte fuel cells, molten carbonate fuel cells, and solid oxide fuel cells have been demonstrated at commercial size in power plants. The previously demonstrated phosphoric acid fuel cells have entered the marketplace with more than 220 power plants delivered. Highlighting this commercial entry, the phosphoric acid power plant fleet has demonstrated 95+% availability and several units have passed 40,000 hours of operation. One unit has operated over 49,000 hours. Early expectations of very low emissions and relatively high efficiencies have been met in power plants with each type of fuel cell. Fuel flexibility has been demonstrated using natural gas, propane, landfill gas, anaerobic digester gas, military logistic fuels, and coal gas, greatly expanding market opportunities. Transportation markets worldwide have shown remarkable interest in fuel cells; nearly every major vehicle manufacturer in the U.S., Europe, and the Far East is supporting development. This Handbook provides a foundation in fuel cells for persons wanting a better understanding of the technology, its benefits, and the systems issues that influence its application. Trends in technology are discussed, including next-generation concepts that promise ultrahigh efficiency and low cost, while providing exceptionally clean power plant systems. Section 1 summarizes fuel cell progress since the last edition and includes existing power plant nameplate data. Section 2 addresses the thermodynamics of fuel cells to provide an understanding of fuel cell operation at two levels (basic and advanced). Sections 3 through 8 describe the six major fuel cell types and their performance based on cell operating conditions. Alkaline and intermediate solid state fuel cells were added to this edition of the Handbook. New information indicates that manufacturers have stayed

  2. Peclet number analysis of cross-flow in porous gas diffusion layer of polymer electrolyte membrane fuel cell (PEMFC).

    Science.gov (United States)

    Suresh, P V; Jayanti, Sreenivas

    2016-10-01

    Adoption of hydrogen economy by means of using hydrogen fuel cells is one possible solution for energy crisis and climate change issues. Polymer electrolyte membrane (PEM) fuel cell, which is an important type of fuel cells, suffers from the problem of water management. Cross-flow is induced in some flow field designs to enhance the water removal. The presence of cross-flow in the serpentine and interdigitated flow fields makes them more effective in proper distribution of the reactants on the reaction layer and evacuation of water from the reaction layer than diffusion-based conventional parallel flow fields. However, too much of cross-flow leads to flow maldistribution in the channels, higher pressure drop, and membrane dehydration. In this study, an attempt has been made to quantify the amount of cross-flow required for effective distribution of reactants and removal of water in the gas diffusion layer. Unit cells containing two adjacent channels with gas diffusion layer (GDL) and catalyst layer at the bottom have been considered for the parallel, interdigitated, and serpentine flow patterns. Computational fluid dynamics-based simulations are carried out to study the reactant transport in under-the-rib area with cross-flow in the GDL. A new criterion based on the Peclet number is presented as a quantitative measure of cross-flow in the GDL. The study shows that a cross-flow Peclet number of the order of 2 is required for effective removal of water from the GDL. Estimates show that this much of cross-flow is not usually produced in the U-bends of Serpentine flow fields, making these areas prone to flooding.

  3. High-performance Platinum-free oxygen reduction reaction and hydrogen oxidation reaction catalyst in polymer electrolyte membrane fuel cell.

    Science.gov (United States)

    Chandran, Priji; Ghosh, Arpita; Ramaprabhu, Sundara

    2018-02-26

    The integration of polymer electrolyte membrane fuel cell (PEMFC) stack into vehicles necessitates the replacement of high-priced platinum (Pt)-based electrocatalyst, which contributes to about 45% of the cost of the stack. The implementation of high-performance and durable Pt metal-free catalyst for both oxygen reduction reaction (ORR) and hydrogen oxidation reaction (HOR) could significantly enable large-scale commercialization of fuel cell-powered vehicles. Towards this goal, a simple, scalable, single-step synthesis method was adopted to develop palladium-cobalt alloy supported on nitrogen-doped reduced graphene oxide (Pd 3 Co/NG) nanocomposite. Rotating ring-disk electrode (RRDE) studies for the electrochemical activity towards ORR indicates that ORR proceeds via nearly four-electron mechanism. Besides, the mass activity of Pd 3 Co/NG shows an enhancement of 1.6 times compared to that of Pd/NG. The full fuel cell measurements were carried out using Pd 3 Co/NG at the anode, cathode in conjunction with Pt/C and simultaneously at both anode and cathode. A maximum power density of 68 mW/cm 2 is accomplished from the simultaneous use of Pd 3 Co/NG as both anode and cathode electrocatalyst with individual loading of 0.5 mg/cm 2 at 60 °C without any backpressure. To the best of our knowledge, the present study is the first of its kind of a fully non-Pt based PEM full cell.

  4. Improved Modeling and Understanding of Diffusion-Media Wettability on Polymer-Electrolyte-Fuel-Cell Performance

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Adam

    2010-03-05

    A macroscopic-modeling methodology to account for the chemical and structural properties of fuel-cell diffusion media is developed. A previous model is updated to include for the first time the use of experimentally measured capillary pressure -- saturation relationships through the introduction of a Gaussian contact-angle distribution into the property equations. The updated model is used to simulate various limiting-case scenarios of water and gas transport in fuel-cell diffusion media. Analysis of these results demonstrate that interfacial conditions are more important than bulk transport in these layers, where the associated mass-transfer resistance is the result of higher capillary pressures at the boundaries and the steepness of the capillary pressure -- saturation relationship. The model is also used to examine the impact of a microporous layer, showing that it dominates the response of the overall diffusion medium. In addition, its primary mass-transfer-related effect is suggested to be limiting the water-injection sites into the more porous gas-diffusion layer.

  5. Solid oxide fuel cells with apatite-type lanthanum silicate-based electrolyte films deposited by radio frequency magnetron sputtering

    Science.gov (United States)

    Liu, Yi-Xin; Wang, Sea-Fue; Hsu, Yung-Fu; Wang, Chi-Hua

    2018-03-01

    In this study, solid oxide fuel cells (SOFCs) containing high-quality apatite-type magnesium doped lanthanum silicate-based electrolyte films (LSMO) deposited by RF magnetron sputtering are successfully fabricated. The LSMO film deposited at an Ar:O2 ratio of 6:4 on an anode supported NiO/Sm0.2Ce0·8O2-δ (SDC) substrate followed by post-annealing at 1000 °C reveals a uniform and dense c-axis oriented polycrystalline structure, which is well adhered to the anode substrate. A composite SDC/La0·6Sr0·4Co0·2Fe0·8O3-δ cathode layer is subsequently screen-printed on the LSMO deposited anode substrate and fired. The SOFC fabricated with the LSMO film exhibits good mechanical integrity. The single cell with the LSMO layer of ≈2.8 μm thickness reports a total cell resistance of 1.156 and 0.163 Ωcm2, open circuit voltage of 1.051 and 0.982 V, and maximum power densities of 0.212 and 1.490 Wcm-2 at measurement temperatures of 700 and 850 °C, respectively, which are comparable or superior to those of previously reported SOFCs with yttria stabilized zirconia electrolyte films. The results of the present study demonstrate the feasibility of deposition of high-quality LSMO films by RF magnetron sputtering on NiO-SDC anode substrates for the fabrication of SOFCs with good cell performance.

  6. Conductivity measurements of molten metal oxide electrolytes and their evaluation in a direct carbon fuel cell (DCFC)

    Science.gov (United States)

    Yarlagadda, Venkata Raviteja

    2011-12-01

    Since Direct Carbon Fuel Cell (DCFC) technology is in a beginning stage, emphasis should be laid on addressing the fundamental aspects. A molten electrolyte is required to facilitate ionic contact between solid carbon fuel and electrolyte in a DCFC Three different metal oxide electrolytes (Bi2O3 , V2O5, and TeO2) have been chosen based on their ability to form stable liquids in air at higher temperatures. Conductivity data beyond their melting points was not readily available for most of the metal oxides. Conductivity studies concerning the above mentioned molten metal oxides have been thoroughly investigated in this study. A four probe measurement method using an AC milliohm-meter at 1 KHz validated by Electrochemical Impedance Spectroscopy (EIS) was used to acquire the conductivity data because of its accuracy when compared to two probe measurement widely used in literature. Also, a DC ohmmeter was used to check whether these metal oxides exhibit electronic conductivity. Experimental results corresponding to the accuracy of DC ohmmeter showed that, it accurately detected the electronic component of the electrolyte. These conductivity studies revealed that the molten oxide electrolytes exhibit high ionic conductivity, in particular, beyond their melting points. Of all the three metal oxides, Bi2O 3 demonstrated high ionic conductivity but with minor stability issues under CO2 environment. Under CO2 environment Bi 2O3 showed a slight decrease in the conductivity. EDX analysis revealed an increase in carbon content by 50 percent per one mole of bismuth which can be attributed to possible carbonate formation. V2O 5 exhibited lower ionic conductivity when compared to Bi2O 3 but had the advantage of lower cost and higher abundance. Also, the higher volumetric expansion of V2O5 upon cooling from its melting point i.e. 690°C caused the alumina crucible containing the metal oxide to break leading to leakage problems. Investigating further, quartz was found to be the best

  7. Unraveling micro- and nanoscale degradation processes during operation of high-temperature polymer-electrolyte-membrane fuel cells

    Science.gov (United States)

    Hengge, K.; Heinzl, C.; Perchthaler, M.; Varley, D.; Lochner, T.; Scheu, C.

    2017-10-01

    The work in hand presents an electron microscopy based in-depth study of micro- and nanoscale degradation processes that take place during the operation of high-temperature polymer-electrolyte-membrane fuel cells (HT-PEMFCs). Carbon supported Pt particles were used as cathodic catalyst material and the bimetallic, carbon supported Pt/Ru system was applied as anode. As membrane, cross-linked polybenzimidazole was used. Scanning electron microscopy analysis of cross-sections of as-prepared and long-term operated membrane-electrode-assemblies revealed insight into micrometer scale degradation processes: operation-caused catalyst redistribution and thinning of the membrane and electrodes. Transmission electron microscopy investigations were performed to unravel the nanometer scale phenomena: a band of Pt and Pt/Ru nanoparticles was detected in the membrane adjacent to the cathode catalyst layer. Quantification of the elemental composition of several individual nanoparticles and the overall band area revealed that they stem from both anode and cathode catalyst layers. The results presented do not demonstrate any catastrophic failure but rather intermediate states during fuel cell operation and indications to proceed with targeted HT-PEMFC optimization.

  8. Amphoteric water as acid and base for protic ionic liquids and their electrochemical activity when used as fuel cell electrolytes.

    Science.gov (United States)

    Miran, Muhammed Shah; Yasuda, Tomohiro; Tatara, Ryoichi; Abu Bin Hasan Susan, Md; Watanabe, Masayoshi

    2017-12-14

    Amphoteric water was mixed with equimolar amounts of a super-strong acid, trifluoromethanesulfonic acid (TfOH), and a super-strong base, 1,8-diazabicyclo[5.4.0]-7-undecene (DBU). Bulk physicochemical and electrochemical properties of the mixtures were compared with those of the best ever reported protic ionic liquid (PIL), diethylmethylammonium trifluoromethanesulfonate ([dema][TfO]), which has excellent physicochemical properties as a fuel cell electrolyte. The acidic mixture ([H 3 O][TfO]) behaved as a protic ionic liquid, while the basic mixture ([DBU]OH) showed incomplete proton transfer. The Walden plot indicated that [H 3 O][TfO] behaves as a good PIL, similar to [dema][TfO], whereas [DBU]OH behaves as a poor PIL. [H 3 O][TfO] showed excellent H 2 /O 2 fuel cell performance at 80 °C; however, the performance deteriorated as the bulk water content increased, because of the retardation of the electrode kinetics due to the oxidation of Pt in the presence of bulk water. On the other hand, [DBU]OH exhibited very poor performance possibly because of the existence of neutral species in the system.

  9. Investigation of concentration overpotential distribution in a polymer electrolyte fuel cell. Paper no. IGEC-1-081

    International Nuclear Information System (INIS)

    Tajiri, K.; Yang, X.-G.; Wang, C.-Y.; Shinohara, K.

    2005-01-01

    Simultaneous measurement of current and high frequency resistance (HFR) distributions has been performed using a segmented polymer electrolyte fuel cell operated with H 2 /air. Each flow plate consisted of twelve segments along a serpentine flow field. Two types of gas diffusion layer (GDL), a treated hydrophobic carbon cloth coated with a microporous layer (MPL) on one side, and an untreated hydrophilic carbon cloth without MPL, were studied and contrasted. The total voltage loss is divided into three overpotentials: the activation, ohmic and concentration; and the concentration overpotential and its distribution are analyzed in detail. While the fuel cell using the GDL with MPL features a nearly uniform concentration overpotential profile, the one without-MPL shows an increase in concentration overpotential along the cathode flow. When the local concentration overpotential is plotted against the local oxygen concentration, the carbon cloth GDL without MPL showed a steeply increasing concentration overpotential with decreasing oxygen concentration, indicating a high sensitivity to the oxygen content. The same trend was observed for the GDL without MPL under lower relative humidity gases. It is thus found that the increase in concentration overpotential with decreasing oxygen concentration is related to the absence of MPL. (author)

  10. A macroscopic model of proton transport through the membrane-ionomer interface of a polymer electrolyte membrane fuel cell

    Science.gov (United States)

    Kumar, Milan; Edwards, Brian J.; Paddison, Stephen J.

    2013-02-01

    The membrane-ionomer interface is the critical interlink of the electrodes and catalyst to the polymer electrolyte membrane (PEM); together forming the membrane electrode assembly in current state-of-the-art PEM fuel cells. In this paper, proton conduction through the interface is investigated to understand its effect on the performance of a PEM fuel cell. The water containing domains at this interface were modeled as cylindrical pores/channels with the anionic groups (i.e., -SO3-) assumed to be fixed on the pore wall. The interactions of each species with all other species and an applied external field were examined. Molecular-based interaction potential energies were computed in a small test element of the pore and were scaled up in terms of macroscopic variables. Evolution equations of the density and momentum of the species (water molecules and hydronium ions) were derived within a framework of nonequilibrium thermodynamics. The resulting evolution equations for the species were solved analytically using an order-of-magnitude analysis to obtain an expression for the proton conductivity. Results show that the conductivity increases with increasing water content and pore radius, and strongly depends on the separation distance between the sulfonate groups and their distribution on the pore wall. It was also determined that the conductivity of two similar pores of different radii in series is limited by the pore with the smaller radius.

  11. Electrochemical determination of activation energies for methanol oxidation on polycrystalline platinum in acidic and alkaline electrolytes.

    Science.gov (United States)

    Cohen, Jamie L; Volpe, David J; Abruña, Héctor D

    2007-01-07

    The oxidation pathways of methanol (MeOH) have been the subject of intense research due to its possible application as a liquid fuel in polyelectrolyte membrane (PEM) fuel cells. The design of improved catalysts for MeOH oxidation requires a deep understanding of these complex oxidation pathways. This paper will provide a discussion of the literature concerning the extensive research carried out in acidic and alkaline electrolytes. It will highlight techniques that have proven useful in the determination of product ratios, analysis of surface poisoning, anion adsorption, and oxide formation processes, in addition to the effects of temperature on the MeOH oxidation pathways at bulk polycrystalline platinum (Pt(poly)) electrodes. This discussion will provide a framework with which to begin the analysis of activation energy (E(a)) values. This kinetic parameter may prove useful in characterizing the rate-limiting step of the MeOH oxidation at an electrode surface. This paper will present a procedure for the determination of E(a) values for MeOH oxidation at a Pt(poly) electrode in acidic and alkaline media. Values from 24-76 kJ mol(-1) in acidic media and from 36-86 kJ mol(-1) in alkaline media were calculated and found to be a function of applied potential and direction of the potential sweep in a voltammetric experiment. Factors that influence the magnitude of the calculated E(a) include surface poisoning from MeOH oxidation intermediates, anion adsorption from the electrolyte, pH effects, and oxide formation processes. These factors are all potential, and temperature, dependent and must clearly be addressed when citing E(a) values in the literature. Comparison of E(a) values must be between systems of comparable electrochemical environment and at the same potential. E(a) values obtained on bulk Pt(poly), compared with other catalysts, may give insight into the superiority of other Pt-based catalysts for MeOH oxidation and lead to the development of new catalysts

  12. A review of high-temperature polymer electrolyte membrane fuel-cell (HT-PEMFC)-based auxiliary power units for diesel-powered road vehicles

    Science.gov (United States)

    Liu, Yongfeng; Lehnert, Werner; Janßen, Holger; Samsun, Remzi Can; Stolten, Detlef

    2016-04-01

    This paper presents an extensive review of research on the development of auxiliary power units with enhanced reformate tolerance for high temperature polymer electrolyte membrane fuel cells (HT-PEMFCs). Developments in diesel reforming for fuel cells as auxiliary power units (APUs), single fuel cells and stacks and systems are outlined in detail and key findings are presented. Summaries of HT-PEMFC APU applications and start-up times for HT-PEMFC systems are then given. A summary of cooling HT-PEMFC stacks using a classic schematic diagram of a 24-cell HT-PEMFC stack, with a cooling plate for every third cell, is also presented as part of a stack analysis. Finally, a summary of CO tolerances for fuel cells is given, along with the effects of different CO volume fractions on polarization curves, the fraction of CO coverage, hydrogen coverage, anode overpotential and cell potential.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, D.

    2007-03-27

    This work deals with selected aspects of mass transport phenomena in PEFCs and DMFCs. Emphasis is placed on the implications originating from the occurrence of two-phase flow within these devices. Optimality of supply, distribution, and removal of the fuel, the oxidant, and the reaction products is of utmost importance for the stability, efficiency, and durability of the devices. Being a prerequisite for high current densities while maintaining sufficient voltage, mass transport optimization contributes to the development of cost effective as well as compact designs and hence competitive fuel cells. [German] Die Visualisierung und Quantifizierung von Fluessigwasseransammlungen in Polymerelektrolytmembran-Brennstoffzellen konnte mittels Neutronenradiographie erreicht werden. Dank dieser neuartigen diagnostischen Methode konnte erstmals die Fluessigwasseransammlung in den poroesen Gasdiffusionsschichten direkt nachgewiesen und quantifiziert werden. Die Kombination von Neutronenradiographie mit ortsaufgeloesten Stromdichtemessungen bzw. lokaler Impedanzspektroskopie erlaubte die Korrelation des inhomogenen Fluessigwasseranfalls mit dem lokalen elektrochemischen Leistungsverhalten. Systematische Untersuchungen an Polymerelektrolyt- und Direkt-Methanol-Brennstoffzellen verdeutlichen sowohl den Einfluss von Betriebsbedingungen als auch die Auswirkung von Materialeigenschaften auf die Ausbildung zweiphasiger Stroemungen.

  14. 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)

  15. Solvent activities of the fluorinated solid polymer electrolyte/water system in fuel cells

    Science.gov (United States)

    Kim, Tae Hwan; Bae, Young Chan

    We modified the lattice fluid equation-of-state by the introducing Debye-Hückel equation. A thermodynamic model taking into account the specific interaction and ionic strength between the polymer and the solvent is proposed. The proposed model successfully predicts the vapor/liquid equilibria (VLE) of solvents and the solid polymer electrolyte (SPE). A generalized lattice fluid model is modified to describe the change of water activity in solid polymer electrolyte (SPE)/water systems. The calculated activity curves using the proposed model agree remarkably well with the experimental data.

  16. A Graphite Oxide Paper Polymer Electrolyte for Direct Methanol Fuel Cells

    Directory of Open Access Journals (Sweden)

    Ravi Kumar

    2011-01-01

    Full Text Available A flow directed assembly of graphite oxide solution was used in the formation of free-standing graphene oxide paper of approximate thickness of 100 μm. The GO papers were characterised by XRD and SEM. Electrochemical characterization of the GO paper membrane electrode assembly revealed proton conductivities of 4.1 × 10−2 S cm−1 to 8.2 × 10−2 S cm−1 at temperatures of 25–90°C. A direct methanol fuel cell, at 60°C, gave a peak power density of 8 mW cm−2 at a current density of 35 mA cm−2.

  17. A Graphite Oxide Paper Polymer Electrolyte for Direct Methanol Fuel Cells

    OpenAIRE

    Kumar, Ravi; Mamlouk, Mohamed; Scott, Keith

    2011-01-01

    A flow directed assembly of graphite oxide solution was used in the formation of free-standing graphene oxide paper of approximate thickness of 100 μm. The GO papers were characterised by XRD and SEM. Electrochemical characterization of the GO paper membrane electrode assembly revealed proton conductivities of 4.1 × 10−2 S cm−1 to 8.2 × 10−2 S cm−1 at temperatures of 25–90°C. A direct methanol fuel cell, at 60°C, gave a peak power density of 8 mW cm−2 at a current density of 35 mA cm−2....

  18. Distribution of the Current Density in Electrolyte of the Pem Fuel Cell

    Directory of Open Access Journals (Sweden)

    Eugeniusz Kurgan

    2004-01-01

    Full Text Available In this paper water management in proton exchange membrane (PEM fuel cell is considered. Firt mass convervation law for water is applied. Next proton transport is described by the Nernst-Planck equation and liqid water convection velocity is eliminated by the Schlogl equation. Electro-osmotic drag coefficient is related to hydrogen index and experimentally determined swelling coefficient. Three partial differential equations for molar water concentration Cw, electric potential ϕ and water pressure Pw are formulated. Current density vector i is derived from proton flux expression. These equations together with adequate boundary conditions were solved using finite element method. The distribution of electric potential and current density in function of geometrical parametres is investigated. At the end some illustrative example is given.

  19. Bacterial nanocellulose/Nafion composite membranes for low temperature polymer electrolyte fuel cells

    Science.gov (United States)

    Jiang, Gao-peng; Zhang, Jing; Qiao, Jin-li; Jiang, Yong-ming; Zarrin, Hadis; Chen, Zhongwei; Hong, Feng

    2015-01-01

    Novel nanocomposite membranes aimed for both proton-exchange membrane fuel cell (PEMFC) and direct methanol fuel cell (DMFC) are presented in this work. The membranes are based on blending bacterial nanocellulose pulp and Nafion (abbreviated as BxNy, where x and y indicates the mass ratio of bacterial cellulose to Nafion). The structure and properties of BxNy membranes are characterized by FTIR, SEM, TG, DMA and EIS, along with water uptake, swelling behavior and methanol permeability tests. It is found that the BxNy composite membranes with reinforced concrete-like structure show excellent mechanical and thermal stability regardless of annealing. The water uptake plus area and volume swelling ratios are all decreased compared to Nafion membranes. The proton conductivities of pristine and annealed B1N9 are 0.071 and 0.056 S cm-1, respectively, at 30 °C and 100% humidity. Specifically, annealed B1N1 exhibited the lowest methanol permeability of 7.21 × 10-7 cm2 s-1. Through the selectivity analysis, pristine and annealed B1N7 are selected to assemble the MEAs. The performances of annealed B1N7 in PEMFC and DMFC show the maximum power densities of 106 and 3.2 mW cm-2, respectively, which are much higher than those of pristine B1N7 at 25 °C. The performances of the pristine and annealed B1N7 reach a level as high as 21.1 and 20.4 mW cm-2 at 80 °C in DMFC, respectively.

  20. Stability and performance improvement of a polymer electrolyte membrane fuel cell stack by laser perforation of gas diffusion layers

    Energy Technology Data Exchange (ETDEWEB)

    Gerteisen, Dietmar; Sadeler, Christian [Fraunhofer Institute for Solar Energy Systems ISE, Department of Energy Technology, Heidenhofstrasse 2, 79110 Freiburg (Germany)

    2010-08-15

    The performance and stability of a hydrogen-driven polymer electrolyte membrane fuel cell stack (6-cell PEFC stack) are investigated with regard to pore flooding within the gas diffusion layers (GDLs). Two short stacks with various GDLs (Toray TGP-H-060 untreated and laser-perforated) were characterized at different operating conditions by several characterization techniques such as constant current load, polarization curve, chronoamperometry and chronovoltammetry. The experimental results reveal that the perforation of the cathode GDLs improves the water transport in the porous media and thus the performance as well as the stability of the operating stack in medium and high current density range. A reduced pore flooding is verified when using the customized laser-perforated GDLs. The GDL perforation has a huge potential to balance the inhomogeneous in-plane saturation conditions between the inlet and outlet area of the cell and to compensate to a certain degree the effects of temperature distribution within a stack regarding the water management. (author)

  1. Stability and performance improvement of a polymer electrolyte membrane fuel cell stack by laser perforation of gas diffusion layers

    Science.gov (United States)

    Gerteisen, Dietmar; Sadeler, Christian

    The performance and stability of a hydrogen-driven polymer electrolyte membrane fuel cell stack (6-cell PEFC stack) are investigated with regard to pore flooding within the gas diffusion layers (GDLs). Two short stacks with various GDLs (Toray TGP-H-060 untreated and laser-perforated) were characterized at different operating conditions by several characterization techniques such as constant current load, polarization curve, chronoamperometry and chronovoltammetry. The experimental results reveal that the perforation of the cathode GDLs improves the water transport in the porous media and thus the performance as well as the stability of the operating stack in medium and high current density range. A reduced pore flooding is verified when using the customized laser-perforated GDLs. The GDL perforation has a huge potential to balance the inhomogeneous in-plane saturation conditions between the inlet and outlet area of the cell and to compensate to a certain degree the effects of temperature distribution within a stack regarding the water management.

  2. Theoretical study of support effect of Au catalyst for glucose oxidation of alkaline fuel cell anode

    Energy Technology Data Exchange (ETDEWEB)

    Ishimoto, Takayoshi, E-mail: ishimoto@ifrc.kyushu-u.ac.jp [Frontier Energy Research Division, INAMORI Frontier Research Center, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Hamatake, Yumi [Frontier Energy Research Division, INAMORI Frontier Research Center, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Kazuno, Hiroki; Kishida, Takayuki [OLYMPUS Corporation, 2-3 Kuboyama-cho, Hachioji-shi, Tokyo 192-8512 (Japan); Koyama, Michihisa, E-mail: koyama@ifrc.kyushu-u.ac.jp [Frontier Energy Research Division, INAMORI Frontier Research Center, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); International Institute for Carbon-Neutral Energy Research, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan)

    2015-01-01

    Highlights: • The catalytic activity of Au in alkaline solution is studied theoretically. • Carbon and oxide materials are used to estimate support effect for glucose oxidation. • The glucose oxidation on SnO{sub 2}(1 1 0) supported Au catalyst shows high activity. • The charge transfer from Au catalyst to support materials is dominant. - Abstract: We theoretically analyzed the glucose oxidation reaction mechanism and reaction activity of Au catalyst supported by carbon (graphite(0 0 0 1), (101{sup ¯}0), and (112{sup ¯}0)) and oxide (ZrO{sub 2}(1 1 1) and SnO{sub 2}(1 1 0)) in alkaline solution environment by using density functional theory method. We observed large stabilization of Au catalyst on support materials due to the electron transfer in the case of graphite(112{sup ¯}0) and SnO{sub 2}(1 1 0) systems. The catalytic activity for glucose oxidation reaction over Au supported by graphite(101{sup ¯}0) and (112{sup ¯}0) is calculated to be low in comparison with those of unsupported system. We found that SnO{sub 2}(1 1 0) supported Au catalyst shows high activity toward the glucose oxidation. One of the main factors for the observed high catalytic activity is charge transfer from Au catalyst to support materials. When the atomic charge of Au catalyst becomes positive by the support effect, the activity of glucose oxidation reaction on Au catalyst is improved.

  3. Molten carbonate fuel cell

    Science.gov (United States)

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

    1986-07-08

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

  4. Influences of Contact Pressure on the Performances of Polymer Electrolyte Fuel Cells

    Directory of Open Access Journals (Sweden)

    Prakash C. Ghosh

    2013-01-01

    Full Text Available Fuel cells face major challenges in sustaining the laboratory-scale performance during the scale up. The contact resistance mainly arises from the dimensional mismatch between gasket and gas diffusion layer during scale up, which may cause diminution in performance. In the present work, experiment as well as modelling is carried out for different combinations of clamping force and gasket thickness. The polarisation behaviours of PEFCs configured under different clamping torques and gasket thicknesses are analysed. The combination of 0.3 mm gasket and 0.3 mm GDL under 3 Nm and 5 Nm clamping forces offers 480 mΩ cm2 and 148 mΩ cm2 contact resistances, respectively. The configurations under 3 Nm and 5 Nm clamping torques with 0.2 mm thick gasket offer contact resistances as low as 23 mΩ cm2 and 11 mΩ cm2, respectively. The polarisation behaviour obtained from the experiment of such configurations is found to be in good agreement with the modelling results.

  5. 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; Antonino S. Aricò

    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 voltammetry ...

  6. Modeling and simulation of high-temperature polymer electrolyte fuel cells; Modellierung und Simulation von Hochtemperatur-Polymerelektrolyt-Brennstoffzellen

    Energy Technology Data Exchange (ETDEWEB)

    Kvesic, Mirko

    2012-07-01

    Fuel cells are electrochemical energy converters that convert chemical energy of constantly fed reactants directly into electricity. The most commonly used fuel gas in this respect is hydrogen, which is either produced in pure form by electrolysis, for example, or as a hydrogen-rich gas mixture (reformate gas), produced by reforming diesel or kerosene e.g. However, a disadvantage of reformate gas is that it contains additional carbon monoxide (CO), which leads to catalyst poisoning in the fuel cell. Since higher operating temperatures also lead to a higher CO tolerance, the use of high-temperature Polymer-Electrolyte-Fuel-Cells (HT-PEFCs) is particularly suitable for reformate operation. The aim of the presented work is the modeling and CFD-simulation of HT-PEFC stacks with the intention of gaining a better understanding of multi-physical processes in the stack operation as well as the optimization and analysis of existing stack designs. The geometric modeling used is based on the Porous Volume Model, which significantly reduces the required number of computing elements. Furthermore, the electrochemical models for hydrogen / air and reformate / air operation, which were taking the CO poisoning effects into account, are developed in this work and implemented in the software ANSYS / Fluent. The resulting simulations indicated the optimal flow configuration for the stack operation in terms of the homogeneous current density distribution, which has a positive effect on the stack aging. Thus, the current densities showed a strong homogeneity regarding the stack configuration anode / cathode in counter-flow and anode / cooling in co-flow. The influence of cooling strategies was examined for the stack performance in a similar way. In the following, the local temperature distribution as well as temperature peaks within the stack could be predicted and validated with experimental measurements. Further on, the model scalability and thus the general validity of the developed

  7. Two 3D structured Co-Ni bimetallic oxides as cathode catalysts for high-performance alkaline direct methanol fuel cells

    Science.gov (United States)

    Liu, Yan; Shu, Chengyong; Fang, Yuan; Chen, Yuanzhen; Liu, Yongning

    2017-09-01

    Two NiCo2O4 bimetallic oxides were synthesized via a facile hydrothermal method. SEM and TEM observations show that these materials have three-dimensional (3D) dandelion-like (DL) and flower-like (FL) morphologies. Their large specific surface areas (90.68 and 19.8 m2·g-1) and porous structures provide many active sites and effective transport pathways for the oxygen reduction reaction (ORR). Electrochemical measurements with a rotating ring-disc electrode (RRDE) indicate that the electron transfer numbers of the NiCo2O4-DL and NiCo2O4-FL catalysts for ORR in an alkaline solution are 3.97 and 3.91, respectively. Fuel cells were assembled with the bimetallic oxides, PtRu/C and a polymer fiber membrane (PFM) as cathode catalysts, anode catalyst and electrolyte film, respectively. For NiCo2O4-DL, the peak power density reaches up to 73.5 mW·cm-2 at 26 °C, which is the highest room-temperature value reported to date. The high catalytic activity of NiCo2O4 is mainly attributed to the presence of many Co3+ cations that directly donate electrons to O2 to reduce it via a more efficient and effective route. Furthermore, the catalytic performance of NiCo2O4-DL is superior to that of NiCo2O4-FL because it has a higher specific surface area and is less crystalline.

  8. Investigation of nanostructured electrocatalysts and mass transport phenomena in polymer electrolyte fuel cells

    Science.gov (United States)

    Goenaga, Gabriel A.

    Proton exchange membrane (PEM) fuel cells (FC) are promising devices in the search of clean and efficient technologies to reduce the use of fossil fuels. However, their poor performance in dynamic applications and high cost of platinum group metal (PGM) catalysts, have prevented them from becoming an affordable solution. This dissertation comprehend three research projects that study the mass transport phenomena in modified PEMs, the reduction of the amount of PGM catalyst used for oxygen reduction reaction (ORR) and the use of non-PGM catalysts as alternative catalyst to Pt for ORR. Nafion is the most used PEM for FC applications. Nafion proton conductivity is proportional to its degree of hydration, what imposes low temperature operation to maintain appropriate water content. In this research, Nafion composite membranes doped with hydrophilic metal inorganic particles have been studied using pulse field gradient (PFG) nuclear magnetic resonance (NMR). The Nafion composite membranes were found to have higher water uptake, higher water retention, higher water diffusion and, in some cases, lower methanol diffusion (crossover) than the filler free Nafion membrane. The amount of Pt and PGM catalysts supported on carbon used in the electrodes, has a great impact in the PEMFC cost. In particular, it is of high relevance to reduce the amount of Pt in the cathode electrode, in which the sluggish ORR demands four to five times more Pt catalyst than in the anode. In this thesis is shown that the use of aligned carbon nanotubes (ACNTs) as Pt support, allows a more uniform distribution of the Pt nanoparticles, what in addition to their high hydrophobicity and high corrosive resistance, lead to improved mass transport and stability of the membrane electrode assembly (MEA), when compared to a benchmark MEA that uses Pt catalyst supported on carbon black. The improvement was accomplished using less Pt than in the benchmark MEA. Replacing Pt with non-PGM catalyst can lead to an

  9. Hybrid Organic - Inorganic Polymer Electrolyte Membranes for Low to Medium Temperature Fuel Cells

    NARCIS (Netherlands)

    Cordova Chavez, M.E.

    2017-01-01

    Crude oil, coal and gas are currently the main resources of energy in the world. The World Energy Outlook claimed in 2007 that the major source of energy (about 84%) would still be generated from fossil fuels in 2030. By these projections, the world's fossil fuel reserves will be consumed within a

  10. Performance comparison of long and short-side chain perfluorosulfonic membranes for high temperature polymer electrolyte membrane fuel cell operation

    Science.gov (United States)

    Stassi, A.; Gatto, I.; Passalacqua, E.; Antonucci, V.; Arico, A. S.; Merlo, L.; Oldani, C.; Pagano, E.

    A new Aquivion™ E79-03S short-side chain perfluorosulfonic membrane with a thickness of 30 μm (dry form) and an equivalent weight (EW) of 790 g/equiv recently developed by Solvay-Solexis for high-temperature operation was tested in a pressurised (3 bar abs.) polymer electrolyte membrane (PEM) single cell at a temperature of 130 °C. For comparison, a standard Nafion™ membrane (EW 1100 g/equiv) of similar thickness (50 μm) was investigated under similar operating conditions. Both membranes were tested for high temperature operation in conjunction with an in-house prepared carbon supported Pt electrocatalyst. The electrocatalyst consisted of nanosized Pt particles (particle size ∼2 nm) dispersed on a high surface area carbon black. The electrochemical tests showed better performance for the Aquivion™ membrane as compared to Nafion™ with promising properties for high temperature PEM fuel cell applications. Beside the higher open circuit voltage and lower ohmic constraints, a higher electrocatalytic activity was observed at high temperature for the electrocatalyst-Aquivion™ ionomer interface indicating a better catalyst utilization.

  11. Solid oxide reversible cells (SORCs) using LaGaO3-based oxide electrolyte and oxide fuel electrode

    Science.gov (United States)

    Ishihara, Tatsumi

    2017-09-01

    Activity of La0.8Sr0.2FeO3 (LSF) to the fuel electrode reaction in Solid Oxide Reversible Cells (SORCs) was investigated by using La0.9Sr0.1Ga0.8Mg0.2O3 (LSGM) and Ba0.6La0.4CoO3 (BLC) as electrolyte and air electrode, respectively. In electrolysis mode (SOEC), LSF electrode exhibited small overpotential under the atmosphere without H2 co-feeding; the current densities reached -1.42, -0.92, -0.36 A/cm2 at 1.4 V at 900, 800, 700 °C, respectively and H2 formation rate is well agreed with that estimated by Faraday's law. On the other hand, in the SOEC-SOFC reversible mode with the gas composition of 20% steam /20%H2/60%Ar, the maximum power densities of 0.42, 0.28, 0.11 W/cm2 were achieved at 900, 800 and 700 °C, respectively. In addition, the cyclic reversible operation was also investigated at 800 °C, and it was found that the cell showed high stability over 30 cycles. DC polarization measurement suggests that the exchange current density of LSF is 14 mA/cm2 at 700 °C, which is almost the same with that of Ni-YSZ reported. XRD measurement and SEM observation after the reversible measurement suggest that LSF is highly stable under SOEC-SOFC cyclic operation condition. Therefore, LSF is promising as the fuel electrode for SORCs, although the conductivity is not sufficiently high as electrode.

  12. Dihydrogenimidazole modified silica-sulfonated poly(ether ether ketone) hybrid materials as electrolyte membranes for direct ethanol fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Roelofs, Kimball S.; Hirth, Thomas [Fraunhofer Institute for Interfacial Engineering and Biotechnology, Nobelstr. 12, 70569 Stuttgart (Germany); Schiestel, Thomas, E-mail: Thomas.Schiestel@igb.fraunhofer.de [Fraunhofer Institute for Interfacial Engineering and Biotechnology, Nobelstr. 12, 70569 Stuttgart (Germany)

    2011-05-25

    The present study reports on dihydrogenimidazole modified inorganic-organic mixed matrix membranes for possible application as a proton exchange membrane in direct ethanol fuel cells. The polymeric phase consisted mainly of sulfonated poly(ether ether ketone) (sPEEK) with a sulfonation degree of 55%. The inorganic phase was built up from hydrophilic fumed silica particles interconnected with partially hydrolyzed and condensed tetraethoxysilane with a total inorganic loading of 27.3%. This inorganic phase was further modified with N-(3-triethoxysilylpropyl)-4,5-dihydroimidazole (DHIM), which consists of an hydrolyzable inorganic part and a functional organic group. The influence of the modifier on the mixed matrix system was studied by means of various modifier concentrations in various aqueous-ethanolic systems (water, 2 M and 4 M ethanol). Modifier concentration and ethanol concentration of the ethanol-water mixture exhibited significant but opposite effects on the liquid uptake of the mixed matrix membranes. The proton conductivity as well as the proton diffusion coefficient as a function of modifier content showed a linear decrease. The proton conductivity as a function of temperature showed Arrhenius behavior and the activation energy of the mixed matrix membranes was 43.9 {+-} 2.6 kJ mol{sup -1}. High selectivity of proton diffusion coefficient to ethanol permeability coefficient was obtained with high modifier concentrations. At low modifier concentrations, this selectivity was dominated by ethanol permeation and at high modifier concentrations by proton diffusion. The main electrolyte properties can be optimized by setting the DHIM content in mixed matrix membrane. With this approach, tailor-made membranes can be prepared for possible application in direct ethanol fuel cells.

  13. 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.)

  14. Electrolyte bi-layering strategy to improve the performance of an intermediate temperature solid oxide fuel cell: A review

    Science.gov (United States)

    Shri Prakash, B.; Pavitra, R.; Senthil Kumar, S.; Aruna, S. T.

    2018-03-01

    Lowering of operation temperature has become one of the primary goals of solid oxide fuel (SOFC) research as reduced temperature improves the prospects for widespread commercialization of this energy system. Reduced operational temperature also mitigates the issues associated with high temperature SOFCs and paves way not only for the large scale stationary power generation but also makes SOFCs viable for portable and transport applications. However, there are issues with electrolyte and cathode materials at low temperatures, individually as well as in association with other components, which makes the performance of the SOFCs less satisfactory than expected at lowered temperatures. Bi-layering of electrolytes and impregnation of cathodes have emerged as two important strategies to overcome these issues and achieve higher performance at low temperatures. This review article provides the perspective on the strategy of bi-layering of electrolyte to achieve the desired high performance from SOFC at low to intermediate temperatures.

  15. 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.)

  16. Poly(imide benzimidazole)s for high temperature polymer electrolyte membrane fuel cells

    DEFF Research Database (Denmark)

    Yuan, Sen; Guo, Xiaoxia; Aili, David

    2014-01-01

    % orthophosphoric acid under pressure at 180°C to give acid uptakes as high as 780wt% and anhydrous proton conductivity of up to 0.26Scm-1 at elevated temperatures. The PIBI membrane with a 1:1molar ratio of APABI:ODA (PIBI-1/1) and with an acid uptake of 300wt% showed an elastic modulus of 0.1GPa at 160°C, which......, demonstrating the technical feasibility of the novel electrolyte materials. © 2013 Elsevier B.V....

  17. Cross-linked aromatic cationic polymer electrolytes with enhanced stability for high temperature fuel cell applications

    DEFF Research Database (Denmark)

    Ma, Wenjia; Zhao, Chengji; Yang, Jingshuai

    2012-01-01

    Diamine-cross-linked membranes were prepared from cross-linkable poly(arylene ether ketone) containing pendant cationic quaternary ammonium group (QPAEK) solution by a facile and general thermal curing method using 4,4′-diaminodiphenylmethane with rigid framework and 1,6-diaminohexane with flexible...... framework as cross-linker, respectively. Self-cross-linked cationic polymer electrolytes membranes were also prepared for comparison. The diamines were advantageously distributed within the polymeric matrix and its amine function groups interacted with the benzyl bromide of QPAEK, resulting in a double...

  18. Recyclable cross-linked anion exchange membrane for alkaline fuel cell application

    Science.gov (United States)

    Hou, Jianqiu; Liu, Yazhi; Ge, Qianqian; Yang, Zhengjin; Wu, Liang; Xu, Tongwen

    2018-01-01

    Cross-linking can effectively solve the conductivity-swelling dilemma in anion exchange membranes (AEMs) but will generate solid wastes. To address this, we developed an AEM cross-linked via disulfide bonds, bearing quaternary ammonium groups, which can be easily recycled. The membrane (RC-QPPO) with IEC of 1.78 mmol g-1, when cross-linked, showed enhanced mechanical properties and good hydroxide conductivity (24.6 mS cm-1 at 30 °C). Even at higher IEC value (2.13 mmol g-1), it still has low water uptake, low swelling ratio and delivers a peak power density of 150 mW cm-2 at 65 °C. Exploiting the formation of disulfide bonds from -SH groups, the membrane can be readily cross-linked in alkaline condition and recycled by reversibly breaking disulfide bonds with dithiothreitol (DTT). The recycled membrane solution can be directly utilized to cast a brand-new AEM. By washing away the residual DTT with water and exposure to air, it can be cross-linked again and this process is repeatable. During the recycling and cross-linking processes, the membrane showed a slight IEC decrease of 5% due to functional group degradation. The strategy presented here is promising in enhancing AEM properties and reducing the impact of artificial polymers on the environment.

  19. Effects of carbon pretreatment for oxygen reduction in alkaline electrolyte

    Science.gov (United States)

    Pirjamali, Massoud; Kiros, Yohannes

    The effects of different media on carbon pretreatments for oxygen reduction in alkaline electrolyte without application of active electrocatalysts were examined. Low surface area Vulcan XC-72 and high surface area Ketjenblack EC-300 were subjected to aqueous acid (flouric or formic), gaseous (H 2, N 2 or CO 2) and thermal treatments at 600 or 900 °C. Though non-scrubbed air was used, as a result of which carbonate build-up was high and peroxide concentration increased due to the electrode reaction, some of the electrodes resulted in life-tests of more than 2000 h at 65 °C, 6 M KOH with a constant load of 50 mA cm -2 and intermittent polarisations at higher current densities. BET-surface areas and pH changes of more than 60% and weight losses of up to 15% of the carbon blacks were observed after the pretreatment steps. Electrochemical characterisation of the carbons showed that pretreatment steps of the carbon blacks have a significant effect on the long-term stability and activity of the gas diffusion electrodes in alkaline electrolyte.

  20. Fuel cells - An option for the future

    International Nuclear Information System (INIS)

    Vielstich, W.

    1984-01-01

    The direct conversion of the energy of a fuel into electrical energy in fuel cells avoids the losses inseparable from the indirect conversion via heat and mechanical energy. The idea to use this concept of energy conversion for the application in power stations would offer the following advantages: a slightly better total energy efficiency; no environmental problems; and flexibility in size according to the construction in the battery stacks. The use of acid and alkaline H 2 /O 2 fuel cells in the U.S. space program has demonstrated the high energy per weight data possible with a fuel cell device including tankage. Therefore, the application of fuel cells in electric vehicles seems to be suitable at least from the technical point of view. Kordesch has converted an Austin A-40 to electric propulsion by replacing the gasoline engine by an 8-kW truck motor powered by a 6-kW alkaline hydrogen-air fuel cell/4-kW lead-acid hybrid system. Two severe handicaps that occurred were the use of gas cylinders for the storage of the hydrogen and the voluminous CO 2 scrubber to prevent carbonization of the alkaline electrolyte. The direct conversion of a liquid fuel like methanol would be advantageous

  1. Investigation of liquid water in gas diffusion layers of polymer electrolyte fuel cells using X-ray tomographic microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Flueckiger, Reto [Electrochemistry Laboratory, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Marone, Federica [Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Stampanoni, Marco [Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Institute for Biomedical Engineering, University and ETH Zurich, Gloriastrasse 35, CH-8092 Zurich (Switzerland); Wokaun, Alexander [Electrochemistry Laboratory, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Buechi, Felix N., E-mail: felix.buechi@psi.c [Electrochemistry Laboratory, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland)

    2011-02-01

    In polymer electrolyte fuel cells (PEFCs), condensation of water within the pore network of the gas diffusion layers (GDL) can influence the gas transport properties and thus reduce the electrochemical conversion rates. The use of X-ray tomographic microscopy (XTM), which allows for a resolution in the order of one micrometer is investigated for studying ex situ the local saturation in GDL's. The strength of XTM is the high spatial resolution with simultaneous contrast for water and carbon, allowing for non-destructive 3D-imaging of the solid and the contained water. The application of this method for imaging the ex situ water intrusion into the porous network of GDLs is explored using absorption and phase contrast methods. It is shown that the inhomogeneous filling behavior of GDL materials can indeed be visualized with sufficient resolution. For Toray paper TGP-H-060 the local saturation was measured as function of the water pressure. The results, evaluated in 1D, 2D and 3D show a liquid water retention effect at the denser layers near the surface. A comparison with established capillary pressure functions is presented. Altogether, the results show the potential of the XTM-method as a tool for studying the liquid water behavior in PEFC on a microscopic scale.

  2. Investigation of liquid water in gas diffusion layers of polymer electrolyte fuel cells using X-ray tomographic microscopy

    International Nuclear Information System (INIS)

    Flueckiger, Reto; Marone, Federica; Stampanoni, Marco; Wokaun, Alexander; Buechi, Felix N.

    2011-01-01

    In polymer electrolyte fuel cells (PEFCs), condensation of water within the pore network of the gas diffusion layers (GDL) can influence the gas transport properties and thus reduce the electrochemical conversion rates. The use of X-ray tomographic microscopy (XTM), which allows for a resolution in the order of one micrometer is investigated for studying ex situ the local saturation in GDL's. The strength of XTM is the high spatial resolution with simultaneous contrast for water and carbon, allowing for non-destructive 3D-imaging of the solid and the contained water. The application of this method for imaging the ex situ water intrusion into the porous network of GDLs is explored using absorption and phase contrast methods. It is shown that the inhomogeneous filling behavior of GDL materials can indeed be visualized with sufficient resolution. For Toray paper TGP-H-060 the local saturation was measured as function of the water pressure. The results, evaluated in 1D, 2D and 3D show a liquid water retention effect at the denser layers near the surface. A comparison with established capillary pressure functions is presented. Altogether, the results show the potential of the XTM-method as a tool for studying the liquid water behavior in PEFC on a microscopic scale.

  3. Voltage Oscillations in a Polymer Electrolyte Membrane Fuel Cell with Pd-Pt/C and Pd/C Anodes.

    Science.gov (United States)

    Nogueira, Jéssica Alves; Varela, Hamilton

    2017-10-01

    Polymer electrolyte membrane fuel cells (PEMFC) fed with H 2 contaminated with CO may exhibit oscillatory behavior when operated galvanostatically. The self-organization of the anodic overpotential is interesting because it can be accompanied by an increase in the average performance. Herein we report experimental studies of voltage oscillations that emerge in a PEMFC equipped with a Pd/C or PdPt/C anode and fed with H 2 contaminated with CO (100 ppm). We used on-line mass spectrometry to investigate how the mass fragments associated with CO 2 and CO ( m / z 44 and 28, respectively) varied with the voltage oscillations. Overall, we observed that oscillations in the anodic overpotential are in phase with that of the CO and CO 2 signals. This fact is consistent with an autonomous adsorption-oxidation cyclic process. For both anodes, it has been observed that, in general, an increase in current density implies an increase in oscillatory frequency. By using CO stripping, we also discuss how the onset of CO oxidation is related to the maximum overpotential reached during a cycle, whereas the minimum overpotential can be associated with the catalytic activity of the electrode for H 2 oxidation.

  4. An electrochemical impedance spectroscopy study of polymer electrolyte membrane fuel cells electrocatalyst single wall carbon nanohorns-supported.

    Science.gov (United States)

    Brandão, Lúcia; Boaventura, Marta; Passeira, Carolina; Gattia, Daniele Mirabile; Marazzi, Renzo; Antisari, Marco Vittori; Mendes, Adélio

    2011-10-01

    Electrochemical impedance spectroscopy (EIS) was used to study the polymer electrolyte membrane fuel cells (PEMFC) performance when using single wall carbon nanohorns (SWNH) to support Pt nanoparticles. Additionally, as-prepared and oxidized SWNH Pt-supports were compared with conventional carbon black. Two different oxidizing treatments were considered: oxygen flow at 500 degrees C and reflux in an acid solution at 85 degrees C. Both oxidizing treatments increased SWNH surface area; oxygen treatment increased surface area 4 times while acid treatment increased 2.6 times. The increase in surface area should be related to the opening access to the inner tube of SWNH. Acid treatment of SWNH increased chemical fragility and decreased electrocatalyst load in comparison with as-prepared SWNH. On the other hand, the oxygen treated SWNH sample allowed to obtain the highest electrocatalyst load. The use of as-prepared and oxygen treated SWNH showed in both cases catalytic activities 60% higher than using conventional carbon black as electrocatalyst support in PEMFC. Moreover, EIS analysis indicated that the major improvement in performance is related to the cathode kinetics in the as-prepared SWNH sample, while concerning the oxidized SWNH sample, the improvements are related to the electrokinetics in both anode and cathode electrodes. These improvements should be related with differences in the hydrophobic character between SWNH and carbon black.

  5. Model-based diagnosis through Structural Analysis and Causal Computation for automotive Polymer Electrolyte Membrane Fuel Cell systems

    Science.gov (United States)

    Polverino, Pierpaolo; Frisk, Erik; Jung, Daniel; Krysander, Mattias; Pianese, Cesare

    2017-07-01

    The present paper proposes an advanced approach for Polymer Electrolyte Membrane Fuel Cell (PEMFC) systems fault detection and isolation through a model-based diagnostic algorithm. The considered algorithm is developed upon a lumped parameter model simulating a whole PEMFC system oriented towards automotive applications. This model is inspired by other models available in the literature, with further attention to stack thermal dynamics and water management. The developed model is analysed by means of Structural Analysis, to identify the correlations among involved physical variables, defined equations and a set of faults which may occur in the system (related to both auxiliary components malfunctions and stack degradation phenomena). Residual generators are designed by means of Causal Computation analysis and the maximum theoretical fault isolability, achievable with a minimal number of installed sensors, is investigated. The achieved results proved the capability of the algorithm to theoretically detect and isolate almost all faults with the only use of stack voltage and temperature sensors, with significant advantages from an industrial point of view. The effective fault isolability is proved through fault simulations at a specific fault magnitude with an advanced residual evaluation technique, to consider quantitative residual deviations from normal conditions and achieve univocal fault isolation.

  6. High-performance anode for Polymer Electrolyte Membrane Fuel Cells by multiple-layer Pt sputter deposition

    Science.gov (United States)

    Natarajan, Sadesh Kumar; Hamelin, Jean

    We investigate the sputtering deposition as a tool for preparing Polymer Electrolyte Membrane Fuel Cell (PEMFC) electrodes with improved performance and catalyst utilization. Anodes of PEMFC with ultra-low loading of Pt (0.05 mg cm -2) are developed by alternate sputtering of Pt and painting layers of carbon nanotube ink with Nafion directly on the gas diffusion layer. Sputter depositing alternate layers of Pt on carbon-Nafion layer (CNL) has increased the anode activity over single-layer Pt deposited anode due to improved porosity and the presence of Pt nanoparticles in the inner CNL. Also, we investigated the influence of Nafion content in the CNL. The optimal Nafion content giving less resistance and better performance in an anode is 29 wt.%. This is significantly lower than for standard MEA anodes, indicating sufficient interfacial contact between each CNL. We studied the anodes prepared with 50 wt.% Nafion, which revealed larger ohmic resistance and also, blocks the CNL pores reducing gas permeability. Excellent mass transfer and performance is obtained with three-layer Pt sputter deposited anode with CNL containing 29 wt.% of Nafion.

  7. X-ray photoemission spectroscopy analysis of N-containing carbon-based cathode catalysts for polymer electrolyte fuel cells

    Science.gov (United States)

    Niwa, Hideharu; Kobayashi, Masaki; Horiba, Koji; Harada, Yoshihisa; Oshima, Masaharu; Terakura, Kiyoyuki; Ikeda, Takashi; Koshigoe, Yuka; Ozaki, Jun-ichi; Miyata, Seizo; Ueda, Shigenori; Yamashita, Yoshiyuki; Yoshikawa, Hideki; Kobayashi, Keisuke

    We report on the electronic structure of three different types of N-containing carbon-based cathode catalysts for polymer electrolyte fuel cells observed by hard X-ray photoemission spectroscopy. Prepared samples are derived from: (1) melamine and poly(furfuryl alcohol), (2) nitrogen-doped carbon black and (3) cobalt phthalocyanine and phenolic resin. C 1 s spectra show the importance of sp 2 carbon network formation for the oxygen reduction reaction (ORR) activity. N 1 s spectra of the carbon-based cathode catalysts are decomposed into four components identified as pyridine-like, pyrrole- or cyanide-like, graphite-like, and oxide nitrogen. Samples having high oxygen reduction reaction activity in terms of oxygen reduction potential contain high concentration of graphite-like nitrogen. O 1 s spectra are similar among carbon-based cathode catalysts of different oxygen reduction reaction activity. There is no correlation between the ORR activity and oxygen content. Based on a quantitative analysis of our results, the oxygen reduction reaction activity of the carbon-based cathode catalysts will be improved by increasing concentration of graphite-like nitrogen in a developed sp 2 carbon network.

  8. 4D imaging of polymer electrolyte membrane fuel cell catalyst layers by soft X-ray spectro-tomography

    Science.gov (United States)

    Wu, Juan; Melo, Lis G. A.; Zhu, Xiaohui; West, Marcia M.; Berejnov, Viatcheslav; Susac, Darija; Stumper, Juergen; Hitchcock, Adam P.

    2018-03-01

    4D imaging - the three-dimensional distributions of chemical species determined using multi-energy X-ray tomography - of cathode catalyst layers of polymer electrolyte membrane fuel cells (PEM-FC) has been measured by scanning transmission x-ray microscopy (STXM) spectro-tomography at the C 1s and F 1s edges. In order to monitor the effects of radiation damage on the composition and 3D structure of the perfluorosulfonic acid (PFSA) ionomer, the same volume was measured 3 times sequentially, with spectral characterization of that same volume at several time points during the measurements. The changes in the average F 1s spectrum of the ionomer in the cathode as the measurements progressed gave insights into the degree of chemical modification, fluorine mass loss, and changes in the 3D distributions of ionomer that accompanied the spectro-tomographic measurement. The PFSA ionomer-in-cathode is modified both chemically and physically by radiation damage. The 3D volume decreases anisotropically. By reducing the incident flux, partial defocusing (50 nm spot size), limiting the number of tilt angles to 14, and using compressed sensing reconstruction, we show it is possible to reproducibly measure the 3D structure of ionomer in PEM-FC cathodes at ambient temperature while causing minimal radiation damage.

  9. Effects of Pt and ionomer ratios on the structure of catalyst layer: A theoretical model for polymer electrolyte fuel cells

    Science.gov (United States)

    Ishikawa, H.; Sugawara, Y.; Inoue, G.; Kawase, M.

    2018-01-01

    The 3D structure of the catalyst layer (CL) in the polymer electrolyte fuel cell (PEFC) is modeled with a Pt/carbon (Pt/C) ratio of 0.4-2.3 and ionomer/carbon (i/C) ratio of 0.5-1.5, and the structural properties are evaluated by numerical simulation. The models are constructed by mimicking the actual shapes of Pt particles and carbon aggregates, as well as the ionomer adhesion in real CLs. CLs with different compositions are characterized by structural properties such as Pt inter-particle distance, ionomer coating thickness, pore size distribution, tortuosity, and ionomer coverage on Pt. The results for Pt/C = 1.0, i/C = 1.0 with Pt loading of 0.3 mg cm-2 and 50% porosity are validated against measured data for CLs with the same composition. With increasing i/C ratio, the smaller pores disappear and the number of isolated pores increases; while the ionomer connection and its coverage on Pt are significantly enhanced at i/C ∼1.0. With increasing Pt/C ratio, the Pt inter-particle distance decreases as the particles connect with each other. The tortuosity of the pores and the ionomer exhibits a trade-off relation depending on the ionomer volume. Further CL design concepts to optimize both O2 diffusion and H+ conduction are discussed.

  10. Fe-doped 8YSZ at different composition for solid electrolyte in solid oxide fuel cell

    Directory of Open Access Journals (Sweden)

    Johar B.

    2016-01-01

    Full Text Available Pure 8 mol% yttria stabilized zirconia (YSZ and Fe-doped (1 mol%, 2 mol% and 3 mol% YSZ electrolyte were prepared and sintered at 1550°C. Transition metal oxide is added into YSZ as sintering aided has a function to reduce the sintering temperature. The microstructure, crystal structure and ionic conductivity of pure YSZ and Fe-doped YSZ at different composition were investigated. The amount of cubic phase decreased as the amount of Fe increased. Fe-doped 8YSZ had higher conductivity than pure 8YSZ. The ionic conductivity of 3FeYSZ is 9.35×10−8 S/cm higher than 1FeYSZ which is 4.72×10−9 S/cm when operated at 300°C.

  11. Commercialization scenarios of polymer electrolyte membrane fuel cell applications for stationary power generation in the United States by the year 2015

    Science.gov (United States)

    Millett, Stephen; Mahadevan, Kathya

    Battelle is identifying the most likely markets and economic impacts of stationary polymer electrolyte membrane (PEM) fuel cells in the range of 1-250 kW in the U.S. by the year 2015. For this task, Battelle is using the Interactive Future Simulations (IFS™), an analytical modeling and forecasting tool that uses expert judgment, trend analysis, and cross-impact analysis methods to generate most likely future conditions for PEM fuel cell applications, market acceptance, commercial viability, and economic impacts. The cross-impact model contains 28 descriptors including commercial and technological advances in both polymer electrolyte membrane (PEM) fuel cells and fossil fuel technologies, sources of hydrogen, investments, public policy, environmental regulation, value to consumers, commercialization leadership, modes of generation, and the reliability and prices of grid electricity. One likely scenario to the year 2015 is that the PEM fuel cells will be limited to commercial and industrial customers in the range of 50-200 kW with a market size less than US$ 5 billion a year.

  12. Investigating the effects of gas diffusion layer substrate thickness on polymer electrolyte membrane fuel cell performance via synchrotron X-ray radiography

    International Nuclear Information System (INIS)

    Lee, J.; Chevalier, S.; Banerjee, R.; Antonacci, P.; Ge, N.; Yip, R.; Kotaka, T.; Tabuchi, Y.; Bazylak, A.

    2017-01-01

    Synchrotron X-ray radiography was used to visualize the liquid water accumulation in polymer electrolyte membrane (PEM) fuel cells to compare the impact of carbon substrate thickness on water management. A differential fuel cell with an active area of 0.68 cm 2 and rib/channel width of 0.2 mm was custom-made to provide 1-dimensional (1D) conditions over the active area. The fuel cell with the thin substrate (TGP-H-030) outperformed the fuel cell with the thick substrate (TGP-H-060). The fuel cell with the thinner substrate exhibited a higher limiting current density, less liquid water in the microporous layer (MPL)-substrate transition region, and reduced oxygen transport resistance measured through electrochemical impedance spectroscopy (EIS). The compression behaviour of each GDL was also investigated through two consecutive fuel cell assemblies. The pressure in the second assembly was lower than that for the initial assemblies for both GDLs, and this significant change in assembly pressure was more pronounced for the thinner GDL (TGP-H-030). The resulting interfacial contact between the catalyst layer and the GDL was degraded, which manifested in the microscale displacement of fuel cell materials during operation (detected as a negative liquid water thickness). While the thinner GDL provided superior performance, the long term effects of material deformation may exacerbate a heterogeneous distribution of liquid water that could also impact the performance.

  13. Towards Highly Performing and Stable PtNi Catalysts in Polymer Electrolyte Fuel Cells for Automotive Application

    Directory of Open Access Journals (Sweden)

    Sabrina C. Zignani

    2017-03-01

    Full Text Available In order to help the introduction on the automotive market of polymer electrolyte fuel cells (PEFCs, it is mandatory to develop highly performing and stable catalysts. The main objective of this work is to investigate PtNi/C catalysts in a PEFC under low relative humidity and pressure conditions, more representative of automotive applications. Carbon supported PtNi nanoparticles were prepared by reduction of metal precursors with formic acid and successive thermal and leaching treatments. The effect of the chemical composition, structure and surface characteristics of the synthesized samples on their electrochemical behavior was investigated. The catalyst characterized by a larger Pt content (Pt3Ni2/C presented the highest catalytic activity (lower potential losses in the activation region among the synthesized bimetallic PtNi catalysts and the commercial Pt/C, used as the reference material, after testing at high temperature (95 °C and low humidification (50% conditions for automotive applications, showing a cell potential (ohmic drop-free of 0.82 V at 500 mA·cm−2. In order to assess the electro-catalysts stability, accelerated degradation tests were carried out by cycling the cell potential between 0.6 V and 1.2 V. By comparing the electrochemical and physico-chemical parameters at the beginning of life (BoL and end of life (EoL, it was demonstrated that the Pt1Ni1/C catalyst was the most stable among the catalyst series, with only a 2% loss of voltage at 200 mA·cm−2 and 12.5% at 950 mA·cm−2. However, further improvements are needed to produce durable catalysts.

  14. 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

  15. Performance Degradation Tests of Phosphoric Acid Doped Polybenzimidazole Membrane Based High Temperature Polymer Electrolyte Membrane Fuel Cells

    DEFF Research Database (Denmark)

    Zhou, Fan; Araya, Samuel Simon; Grigoras, Ionela

    2015-01-01

    Degradation tests of two phosphoric acid (PA) doped PBI membrane based HT-PEM fuel cells were reported in this paper to investigate the effects of start/stop and the presence of methanol in the fuel to the performance degradation of the HT-PEM fuel cell. Continuous tests with pure dry H2 and meth......Degradation tests of two phosphoric acid (PA) doped PBI membrane based HT-PEM fuel cells were reported in this paper to investigate the effects of start/stop and the presence of methanol in the fuel to the performance degradation of the HT-PEM fuel cell. Continuous tests with pure dry H2...... to the corrosion of carbon support in the catalyst layer and degradation of the PBI membrane. During the continuous test with methanol containing H2 as the fuel the reaction kinetic resistance and mass transfer resistance of both single cells increased, which may be caused by the adsorption of methanol...

  16. Fuel Cell Testing - Degradation of Fuel Cells and its Impact on Fuel Cell Applications

    OpenAIRE

    PFRANG Andreas

    2008-01-01

    Fuel cells are expected to play a major role in the future energy supply, especially polymer electrolyte membrane fuel cells could become an integral part in future cars. Reduction of degradation of fuel cell performance while keeping fuel cell cost under control is the key for an introduction into mass markets.

  17. Development of Integrated TiO2 on Carburized Si Nanowires as a Catalyst/Support Structure for Alkaline Fuel Cells

    Science.gov (United States)

    Lemke, Adam J.

    Due to a combination of environmental and economic motivations, there is a strong impetus to transition away from fossil fuels towards renewable sources of energy. Critical to achieving this goal will be technologies that allow for the storage and transmission of energy derived from renewable sources. Hydrogen fuel cells may play a significant role in making this a reality, allowing for the use of hydrogen as a non-carbon based fuel, in particular for vehicle applications. Hydrogen fuel cells directly convert chemical energy into electrical energy, with only water vapor and heat as waste products. There are challenges facing fuel cell technology that inhibit its wider implementation. One of the most significant of these is the cost of the platinum that is typically used in fuel cells to catalyze the oxygen reduction reaction (ORR), which is the bottleneck reaction in hydrogen fuel cells. The rarity and expense of platinum significantly add to the cost of fuel cells, thus reducing their economic viability. Therefore there is much interest in developing catalysts from alternative materials with a lower cost. A second, and related issue facing fuel cells is the degradation over time of the support structure that puts the catalyst into electrical connection with the external load. The carbon structure that currently serves as the standard catalyst support degrades over time under the harsh operating conditions of the cell, leading to catalyst agglomeration and reducing the lifetime of the cell. It is therefore desirable to develop support structures that will be more stable, while still providing electrical conductivity. The following presents original research pertaining to the development of catalyst/support materials making use of non-noble metal oxides synthesized by means of wet chemical methods. Metal oxides such as manganese oxide and titanium oxide are capable of serving as support materials and (in the case of alkaline fuel cells) even as catalysts. Wet

  18. Lignin-derived electrospun carbon nanofiber mats with supercritically deposited Ag nanoparticles for oxygen reduction reaction in alkaline fuel cells

    International Nuclear Information System (INIS)

    Lai, Chuilin; Kolla, Praveen; Zhao, Yong; Fong, Hao; Smirnova, Alevtina L.

    2014-01-01

    Highlights: • Electrospun carbon nanofiber mats were prepared from a natural product of lignin. • The freestanding mats were flexible with BET specific surface area of ∼583 m 2 /g. • The mats were surface-deposited with Ag nanoparticles via the scCO 2 method. • Novel electrocatalytic systems of Ag/ECNFs exhibited high activities towards ORR. - Abstract: Ag nanoparticles (AgNPs) (11, 15, and 25 wt.%) were deposited on the surface of the freestanding and mechanically flexible mats consisting of lignin-derived electrospun carbon nanofibers (ECNFs) by the supercritical CO 2 method followed by the thermal treated at 180 °C. The electrochemical activity of Ag/ECNFs electrocatalyst systems towards oxygen reduction reaction (ORR) was studied in 0.1 M KOH aqueous solution using the rotating disk/rotating ring disk electrode (RDE/RRDE) technique. The SEM, TEM, and XRD results indicated that, the spherical AgNPs were uniformly distributed on the ECNF surface with sizes in the range of 2-10 nm. The electrocatalytic results revealed that, all of the Ag/ECNFs systems exhibited high activity in ORR and demonstrated close-to-theoretical four-electron pathway. In particular, the mass activity of 15 wt.% Ag/ECNFs system was the highest (119 mA mg −1 ), exceeding that of HiSPEC 4100™ commercial Pt/C catalyst (98 mA mg −1 ). This study suggested that the lignin-derived ECNF mats surface-deposited with AgNPs would be promising as cost-effective and highly efficient electrocatalyst for ORR in alkaline fuel cells

  19. Experimental study of cell reversal of a high temperature polymer electrolyte membrane fuel cell caused by H2 starvation

    DEFF Research Database (Denmark)

    Zhou, Fan; Andreasen, Søren Juhl; Kær, Søren Knudsen

    2015-01-01

    under different H2 stoichiometries below 1.0 and at different current loads. The experimental results show that the cell voltage decreases promptly when the H2 stoichiometry decreases to below 1.0. Negative cell voltage can be observed which indicates cell reversal. The local current density starts...... regions, decreasing along the flow channel direction, becoming the lowest in the downstream regions. In addition, the CO2 and even the O2 can be detected in the anode exhaust under fuel starvation conditions, confirming the occurring of carbon corrosion and water electrolysis reactions. With lower H2...... stoichiometry and higher current load, the cell voltage decrease rate is higher and the cell reversal is more severe. Higher CO2 concentration in anode exhaust is measured under these conditions, suggesting the degradation is more severe....

  20. Novel materials for fuel cells operating on liquid fuels

    Directory of Open Access Journals (Sweden)

    César A. C. Sequeira

    2017-05-01

    Full Text Available Towards commercialization of fuel cell products in the coming years, the fuel cell systems are being redefined by means of lowering costs of basic elements, such as electrolytes and membranes, electrode and catalyst materials, as well as of increasing power density and long-term stability. Among different kinds of fuel cells, low-temperature polymer electrolyte membrane fuel cells (PEMFCs are of major importance, but their problems related to hydrogen storage and distribution are forcing the development of liquid fuels such as methanol, ethanol, sodium borohydride and ammonia. In respect to hydrogen, methanol is cheaper, easier to handle, transport and store, and has a high theoretical energy density. The second most studied liquid fuel is ethanol, but it is necessary to note that the highest theoretically energy conversion efficiency should be reached in a cell operating on sodium borohydride alkaline solution. It is clear that proper solutions need to be developed, by using novel catalysts, namely nanostructured single phase and composite materials, oxidant enrichment technologies and catalytic activity increasing. In this paper these main directions will be considered.

  1. Determination of membrane degradation products in the product water of polymer electrolyte membrane fuel cells using liquid chromatography mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Zedda, Marco

    2011-05-12

    The predominant long term failure of polymer electrolyte membranes (PEM) is caused by hydroxyl radicals generated during fuel cell operation. These radicals attack the polymer, leading to chain scission, unzipping and consequently to membrane decomposition products. The present work has investigated decomposition products of novel sulfonated aromatic hydrocarbon membranes on the basis of a product water analysis. Degradation products from the investigated membrane type and the possibility to detect these compounds in the product water for diagnostic purposes have not been discovered yet. This thesis demonstrates the potential of solid phase extraction and liquid chromatography tandem mass spectrometry (SPE-LC-MS/MS) for the extraction, separation, characterization, identification and quantification of membrane degradation products in the product water of fuel cells. For this purpose, several polar aromatic hydrocarbons with different functional groups were selected as model compounds for the development of reliable extraction, separation and detection methods. The results of this thesis have shown that mixed mode sorbent materials with both weak anion exchange and reversed phase retention properties are well suited for reproducible extraction of both molecules and ions from the product water. The chromatographic separation of various polar aromatic hydrocarbons was achieved by means of phase optimized liquid chromatography using a solvent gradient and on a C18 stationary phase. Sensitive and selective detection of model compounds could be successfully demonstrated by the analysis of the product water using tandem mass spectrometry. The application of a hybrid mass spectrometer (Q Trap) for the characterization of unknown polar aromatic hydrocarbons has led to the identification and confirmation of 4-hydroxybenzoic acid in the product water. In addition, 4-HBA could be verified as a degradation product resulting from PEM decomposition by hydroxyl radicals using an

  2. An improved bifunctional oxygen (air) electrode for reversible alkaline fuel cell systems and for rechargeable metal-air batteries

    Science.gov (United States)

    Kordesch, K.; Steininger, K.-H.; Tomantschger, K.

    1988-10-01

    Electrodes with a nickel layer of dual pore structure on the electrolyte side and a PTFE-bonded carbon layer on the oxygen (air) side are discussed, with application to space energy storage. During the electrolyis stage, the oxygen fills the large pores of the porous Ni structure with gas. During the discharge cycle, the iron/air or zinc/air cell of the carbon layer operates as a regular oxygen electrode.

  3. Surface composition effect of nitriding Ni-free stainless steel as bipolar plate of polymer electrolyte fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Yang; Shironita, Sayoko [Nagaoka University of Technology, 1603-1, Kamitomioka, Nagaoka, Niigata 940-2188 (Japan); Nakatsuyama, Kunio [Nakatsuyama Heat Treatment Co., Ltd., 1-1089-10, Nanyou, Nagaoka, Niigata 940-1164 (Japan); Souma, Kenichi [Nagaoka University of Technology, 1603-1, Kamitomioka, Nagaoka, Niigata 940-2188 (Japan); Hitachi Industrial Equipment Systems Co., Ltd., 3 Kanda Neribei, Chiyoda, Tokyo 101-0022 (Japan); Umeda, Minoru, E-mail: mumeda@vos.nagaokaut.ac.jp [Nagaoka University of Technology, 1603-1, Kamitomioka, Nagaoka, Niigata 940-2188 (Japan)

    2016-12-01

    Graphical abstract: The anodic current densities in the passive region of nitrided SUS445-N stainless steel are lower than those of a non heat-treated SUS445 stainless steel and heat-treated SUS445-Ar stainless steel under an Ar atmosphere. It shows a better corrosion resistance for the SUS445 stainless steel after the nitriding heat treatment. - Highlights: • The nitriding heat treatment was carried out using Ni-free SUS445 stainless steel. • The corrosion resistance of the nitrided SUS445-N stainless steel was improved. • The structure of the nitrided SUS445-N stainless steel changed from α-Fe to γ-Fe. • The surface elemental components present in the steels affect the corrosion resistance. - Abstract: In order to increase the corrosion resistance of low cost Ni-free SUS445 stainless steel as the bipolar plate of a polymer electrolyte fuel cell, a nitriding surface treatment experiment was carried out in a nitrogen atmosphere under vacuum conditions, while an Ar atmosphere was used for comparison. The electrochemical performance, microstructure, surface chemical composition and morphology of the sample before and after the electrochemical measurements were investigated using linear sweep voltammetry (LSV), X-ray diffraction (XRD), glow discharge optical emission spectroscopy (GDS) and laser scanning microscopy (LSM) measurements. The results confirmed that the nitriding heat treatment not only increased the corrosion resistance, but also improved the surface conductivity of the Ni-free SUS445 stainless steel. In contrast, the corrosion resistance of the SUS445 stainless steel decreased after heat treatment in an Ar atmosphere. These results could be explained by the different surface compositions between these samples.

  4. Electrical Properties Of Indium And Yttrium-Doped Barium Cerate-Based Compounds For Use As Ceramic Fuel Cell Electrolytes

    Directory of Open Access Journals (Sweden)

    Gawel R.

    2015-06-01

    Full Text Available The aim of this work is to compare the electrical properties of BaCe0.85Y0.15O3−δ (BCY15, BaCe0.70In0.30O3−δ (BCI30 and a composite material consisting of 30%vol. BCY15 and 70%vol. Ce0.85Y0.15O2−δ (YDC15. BCY15 and YDC15 were synthesized by co-precipitation, whereas BCI30 was obtained using the solid-state reaction method. Pellets were initially formed from powders at 5 MPa, after which they were isostatically pressed at 250 MPa and sintered at 1500°C. Electrochemical impedance spectroscopy (EIS was used to determine the electrical properties of the samples in both air (pO2 = 0.021 MPa and Ar-5%H2 atmospheres. In the temperature range 200-400°C in air atmosphere the highest conductivity values were determined for BCY15 (5,22·10−5 − 2.74·10−3 S/cm. On the other hand, the electrical conductivity values obtained for Y70B30 in both atmospheres between 200 and 550°C are in the order of magnitude of 10−7 − 10−3 S/cm. Consequently, it can be concluded that the compounds exhibit significant H+ and O2− electrical conductivity at temperatures above 500°C, which indicates the possibility for their potential use as ceramic fuel cell electrolytes.

  5. Investigation of electrolyte leaching in the performance degradation of phosphoric acid-doped polybenzimidazole membrane-based high temperature fuel cells

    Science.gov (United States)

    Jeong, Yeon Hun; Oh, Kyeongmin; Ahn, Sungha; Kim, Na Young; Byeon, Ayeong; Park, Hee-Young; Lee, So Young; Park, Hyun S.; Yoo, Sung Jong; Jang, Jong Hyun; Kim, Hyoung-Juhn; Ju, Hyunchul; Kim, Jin Young

    2017-09-01

    Precise monitoring of electrolyte leaching in high-temperature polymer electrolyte membrane fuel cell (HT-PEMFC) devices during lifetime tests is helpful in making a diagnosis of their quality changes and analyzing their electrochemical performance degradation. Here, we investigate electrolyte leaching in the performance degradation of phosphoric acid (PA)-doped polybenzimidazole (PBI) membrane-based HT-PEMFCs. We first perform quantitative analyses to measure PA leakage during cell operation by spectrophotometric means, and a higher PA leakage rate is detected when the current density is elevated in the cell. Second, long-term degradation tests under various current densities of the cells and electrochemical impedance spectroscopy (EIS) analysis are performed to examine the influence of PA loss on the membrane and electrodes during cell performance degradation. The combined results indicate that PA leakage affect cell performance durability, mostly due to an increase in charge transfer resistance and a decrease in the electrochemical surface area (ECSA) of the electrodes. Additionally, a three-dimensional (3-D) HT-PEMFC model is applied to a real-scale experimental cell, and is successfully validated against the polarization curves measured during various long-term experiments. The simulation results highlight that the PA loss from the cathode catalyst layer (CL) is a significant contributor to overall performance degradation.

  6. FY 1998 annual report on the development of fuel cell power generation techniques. Research and development of solid electrolyte fuel cells (research results); 1998 nendo nenryo denchi gijutsu kaihatsu. Kotai denkaishitsugata nenryo denchi no kenkyu kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    Described herein are the FY 1998 research and development results of solid electrolyte fuel cells. For R and D of the tubular type cell by the wet processing technique, the tests are conducted to evaluate the initial performance and long-term durability for continuous operation of the single tubular cell. For development of the several-kW class modules, computer-aided simulations are conducted. For R and D of material and substrate techniques, the thermal cycle characteristics, cell characteristics and stress of the cell modules are evaluated, in order to evaluate their reliability. The thermal cycle test results indicate that performance of the single-stage cell is unaffected by the thermal cycles. It is found by the stress evaluation that use of the separator plate having a higher thermal expansion coefficient than the electrolyte plate and use of the sealant having a thermal expansion coefficient close to that of the electrolyte plate are effective means to reduce stresses. For the research to reduce costs of the cell materials, their chemical, mechanical and thermal characteristics are evaluated. For the system research, the areas for which the compact systems are suitable and their optimization are studied. (NEDO)

  7. Fuel Cell Electrodes for Hydrogen-Air Fuel Cell Assemblies.

    Science.gov (United States)

    The report describes the design and evaluation of a hydrogen-air fuel cell module for use in a portable hydrid fuel cell -battery system. The fuel ... cell module consists of a stack of 20 single assemblies. Each assembly contains 2 electrically independent cells with a common electrolyte compartment

  8. Fabrication of Thin Electrolytes for Second-Generation Solid Oxide Fuel Cells

    Science.gov (United States)

    1999-05-05

    temperatures 10-6 K-1) and CeO2 (a = 12.5 X 10-6 K-’). As the around 750’C. Three-layer cells consisting of 1-pLm substrate is much thicker than the film, it is...the slurry for this tech- bly formed due to the high organic content in the nique is similar to that of the paste for the screen green tape. printing...method, and is achieved by conventional methods. By casting the slurry directly onto the 2.3.1.4. Slurry coating technique joining substrate

  9. Application of a Coated Film Catalyst Layer Model to a High Temperature Polymer Electrolyte Membrane Fuel Cell with Low Catalyst Loading Produced by Reactive Spray Deposition Technology

    Directory of Open Access Journals (Sweden)

    Timothy D. Myles

    2015-10-01

    Full Text Available In this study, a semi-empirical model is presented that correlates to previously obtained experimental overpotential data for a high temperature polymer electrolyte membrane fuel cell (HT-PEMFC. The goal is to reinforce the understanding of the performance of the cell from a modeling perspective. The HT-PEMFC membrane electrode assemblies (MEAs were constructed utilizing an 85 wt. % phosphoric acid doped Advent TPS® membranes for the electrolyte and gas diffusion electrodes (GDEs manufactured by Reactive Spray Deposition Technology (RSDT. MEAs with varying ratios of PTFE binder to carbon support material (I/C ratio were manufactured and their performance at various operating temperatures was recorded. The semi-empirical model derivation was based on the coated film catalyst layer approach and was calibrated to the experimental data by a least squares method. The behavior of important physical parameters as a function of I/C ratio and operating temperature were explored.

  10. In-situ observation of dynamic water behavior in polymer electrolyte fuel cell by combined method of Small-Angle Neutron Scattering and Neutron Radiography

    International Nuclear Information System (INIS)

    Putra, A; Yamaguchi, D; Koizumi, S; Hashimoto, T; Iwase, H; Maekawa, Y; Matsubayashi, M

    2010-01-01

    In-situ observation was conducted on an operating polymer electrolyte fuel cell with a combined method of small-angle neutron scattering (SANS) and neutron radiography (NR). The combined measurement system has been recently developed to visualize water in a wide length scale from nano- to millimeter and successfully detected a spatial distribution of the water generated in individual cell elements; NR macroscopically detected the water in a gas diffusion layer and a flow-field, whereas SANS microscopically did in a membrane electrode assembly. In particular SANS was found to be a strong tool to make a rather precise analysis on the water content inside of ion conducting channels of polymer electrolyte membrane.

  11. Fuel cells

    Science.gov (United States)

    Hooie, D. T.; Harrington, B. C., III; Mayfield, M. J.; Parsons, E. L.

    1992-07-01

    The primary objective of DOE's Fossil Energy Fuel Cell program is to fund the development of key fuel cell technologies in a manner that maximizes private sector participation and in a way that will give contractors the opportunity for a competitive posture, early market entry, and long-term market growth. This summary includes an overview of the Fuel Cell program, an elementary explanation of how fuel cells operate, and a synopsis of the three major fuel cell technologies sponsored by the DOE/Fossil Energy Phosphoric Acid Fuel Cell program, the Molten Carbonate Fuel Cell program, and the Solid Oxide Fuel Cell program.

  12. Localised corrosion processes of austenitic stainless steel bipolar plates for polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Mele, Claudio; Bozzini, Benedetto

    This research addresses the problem of localised corrosion of stainless steel PEMFC bipolar plates. The susceptibility to pitting and crevice corrosion of austenitic AISI 304 stainless steel has been investigated both by post-mortem microscopic analysis of the end-plates of a laboratory single-cell and by studies of electrochemically corroded stainless steels, in the presence of specially-designed crevice-formers simulating the operating conditions of a PEMFC. This work is based on optical and scanning-electron microscopies as well as potentiostatic and potentiodynamic measurements. The crevice-formers we considered were: Teflon, graphite and AISI 304. The samples, coupled to the crevice-formers have been tested in aqueous solutions containing Cl -, SO 4 2- and F -. From the E-log i plot, the values of corrosion, pitting, crevice and protection potential have been obtained and perfect and imperfect passivity conditions have been identified.

  13. All-solid-state Al-air batteries with polymer alkaline gel electrolyte

    Science.gov (United States)

    Zhang, Zhao; Zuo, Chuncheng; Liu, Zihui; Yu, Ying; Zuo, Yuxin; Song, Yu

    2014-04-01

    Aluminum-air (Al-air) battery is one of the most promising candidates for next-generation energy storage systems because of its high capacity and energy density, and abundance. The polyacrylic acid (PAA)-based alkaline gel electrolyte is used in all-solid-state Al-air batteries instead of aqueous electrolytes to prevent leakage. The optimal gel electrolyte exhibits an ionic conductivity of 460 mS cm-1, which is close to that of aqueous electrolytes. The Al-air battery peak capacity and energy density considering only Al can reach 1166 mAh g-1-Al and 1230 mWh g-1-Al, respectively, during constant current discharge. The battery prototype also exhibits a high power density of 91.13 mW cm-2. For the battery is a laminated structure, area densities of 29.2 mAh cm-2 and 30.8 mWh cm-2 are presented to appraise the performance of the whole cell. A novel design to inhibit anodic corrosion is proposed by separating the Al anode from the gel electrolyte when not in use, thereby effectively maintaining the available capacity of the battery.

  14. Analysis of the water balance of polymer electrolyte membrane fuel cells; Untersuchung zum Wasserhaushalt von Polymerelektrolytmembran-Brennstoffzellen

    Energy Technology Data Exchange (ETDEWEB)

    Hakenjos, A.

    2006-09-14

    Within this thesis, instruments for the localised characterisation of fuel cells and fuel cell stacks have been created. The simultaneous multi-channel impedance spectroscopy was implemented and applied to fuel cells for the first time. A measurement device has been developed that can be used to simultaneously apply various localised measurement methods to fuel cells during operation. Within this work, mainly current density and localized impedance measurements were used. Additionally, the temperature distribution of the active fuel cell area was determined and the water condensation was visualised. Several fuel cells have been developed, constructed and assembled to carry out localised characterisation. An algorithm has been developed to evaluate impedance spectra that separate the processes in the fuel cell according to their different time constants. This algorithm is based on a system of physical model equations that provide time- and location-dependent descriptions of the different processes in the cell. This allows the quantitive extraction of physical parameters from the impedance spectroscopy results. To perform localised simulation, a three-dimensional, two-phase, stationary model was adopted cell. A simple one-dimensional fuel cell geometry was used to demonstrate that the three-dimensional model reliably describes the processes under various operation conditions. The model validation was also successfully carried out for various complex fuel cell geometries. With the localised characterisation methods, air flow field geometries of fuel cells were successfully analysed. It could be explained how the microporous coating of the diffusion layer influences the current density distribution. The water balance of a number of different gas flow geometries was successfully characterised. As a result, an optimised flow field design with a double meander has been developed. The water content has been improved so that the efficiency is increased, and the current

  15. Study of poly(vinyl alcohol)/titanium oxide composite polymer membranes and their application on alkaline direct alcohol fuel cell

    Science.gov (United States)

    Yang, Chun-Chen; Chiu, Shwu-Jer; Lee, Kuo-Tong; Chien, Wen-Chen; Lin, Che-Tseng; Huang, Ching-An

    The novel poly(vinyl alcohol)/titanium oxide (PVA/TiO 2) composite polymer membrane was prepared using a solution casting method. The characteristic properties of the PVA/TiO 2 composite polymer membrane were investigated by thermal gravimetric analysis (TGA), a scanning electron microscopy (SEM), a micro-Raman spectroscopy, a methanol permeability measurement and the AC impedance method. An alkaline direct alcohol (methanol, ethanol and isopropanol) fuel cell (DAFC), consisting of an air cathode based on MnO 2/C inks, an anode based on PtRu (1:1) black and a PVA/TiO 2 composite polymer membrane, was assembled and examined for the first time. The results indicate that the alkaline DAFC comprised of a cheap, non-perfluorinated PVA/TiO 2 composite polymer membrane shows an improved electrochemical performances. The maximum power densities of alkaline DAFCs with 4 M KOH + 2 M CH 3OH, 2 M C 2H 5OH and 2 M isopropanol (IPA) solutions at room temperature and ambient air are 9.25, 8.00, and 5.45 mW cm -2, respectively. As a result, methanol shows the highest maximum power density among three alcohols. The PVA/TiO 2 composite polymer membrane with the permeability values in the order of 10 -7 to 10 -8 cm 2 s -1 is a potential candidate for use on alkaline DAFCs.

  16. High-performance oxygen reduction catalysts in both alkaline and acidic fuel cells based on pre-treating carbon material and iron precursor

    Energy Technology Data Exchange (ETDEWEB)

    Song, Ping; Barkholtz, Heather M.; Wang, Ying; Xu, Weilin; Liu, Dijia; Zhuang, Lin

    2017-12-01

    We demonstrate a new and simple method for pre-treating the carbon material and iron precursor to prepare oxygen reduction reaction (ORR) catalysts, which can produce super-high performance and stability in alkaline solution, with high performance in acid solution. This strategy using cheap materials is simply controllable. Moreover, it has achieved smaller uniform nanoparticles to exhibit high stability, and the synergetic effect of Fe and N offered much higher performance in ORR than commercial Pt/C, with high maximum power density in alkaline and acid fuel cell test. So it can make this kind of catalysts be the most promising alternatives of Pt-based catalysts with best performance/price.

  17. Electrolytic hydrogen fuel production with solid polymer electrolyte technology.

    Science.gov (United States)

    Titterington, W. A.; Fickett, A. P.

    1973-01-01

    A water electrolysis technology based on a solid polymer electrolyte (SPE) concept is presented for applicability to large-scale hydrogen production in a future energy system. High cell current density operation is selected for the application, and supporting cell test performance data are presented. Demonstrated cell life data are included to support the adaptability of the SPE system to large-size hydrogen generation utility plants as needed for bulk energy storage or transmission. The inherent system advantages of the acid SPE electrolysis technology are explained. System performance predictions are made through the year 2000, along with plant capital and operating cost projections.

  18. Poly-electrolytes for fuel cells: tools and methods for characterization; Polyelectrolytes pour piles a combustible: outils et methodes de caracterisation

    Energy Technology Data Exchange (ETDEWEB)

    Marechal, M.

    2004-12-15

    The research works reported in the manuscript are a contribution to the study of poly-electrolytes for Proton Exchange Membrane Fuel Cells (PEMFC). They are supported by two investigation tools, i.e. the study of model molecules and accurate conductivity measurements. With regard to the material science domain, the optimization of poly-sulfone sulfonation procedure allows chain breaking to be reduced and even eliminated while obtaining reproducible sulfonation degrees. It is thus possible to improve the mechanical properties of the dense membrane elaborated with these poly-electrolytes before performing the tests on the MEA (Membrane Electrode Assembly). In parallel, the functionalization of microporous silicon made it possible to prepare poly-electrolytes reinforced by the mechanical strength of the silicon separator. With regard to the physicochemical and electrochemical characterizations, the model molecules, with the same functions and groups than for associated polymers, make it possible to amplify the electrochemical or thermal phenomena vs. the corresponding polymers. Thus, they simulate an accelerated ageing of the poly-electrolytes. The development of a new conductivity measurement set allows conductivity to be obtained with a great accuracy, in a wide range of temperature and relative humidity. (author)

  19. Synthesis, characterization and electrical properties of solid electrolyte for solid oxide fuel cell; Preparacao, caracterizacao e propriedades eletricas de eletrolito solido para celula a combustivel de oxido solido

    Energy Technology Data Exchange (ETDEWEB)

    Berton, Marco Antonio Coelho; Garcia, Carlos Mario; Matos, Jeferson Hrenechen [Instituto de Tecnologia para o Desenvolvimento (LACTEC), Curitiba, PR (Brazil)], Emails: felsky@latec.org.br, garcia@latec.org.br, jeferson.h@latec.org.br

    2010-04-15

    Solid electrolytes of BaCe{sub 08}Gd{sub O29} were prepared by the polymeric precursor method. X-ray diffraction data shows a single phase with orthorhombic crystalline structure. The densification process was followed by scanning electronic microscopy and apparent density measurements. The apparent density was developed for different temperatures of sintering, reaching > 96% for sintered temperature of 1550 {sup 0}C deg . The electrochemical impedance analysis was development in the temperature of 400-700 deg C, in air atmosphere at 700 deg C a value of 30,6 mS.cm{sup -1} was obtained. The results of conductivity have confirmed the gadolinium doped barium cerate has a great potential for use as solid electrolyte for intermediate temperature solid oxide fuel cell, at experimental controlled conditions. (author)

  20. Enhancement of Oxygen Reduction and Mitigation of Ionomer Dry-Out Using Insoluble Heteropoly Acids in Intermediate Temperature Polymer-Electrolyte Membrane Fuel Cells

    Directory of Open Access Journals (Sweden)

    Alessandro Stassi

    2015-07-01

    Full Text Available The use of Cs0.5H0.5PW12O40 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 voltammetry analysis. These effects are also corroborated by a significant decrease of polarization resistance at intermediate temperatures. Such characteristics have been demonstrated for a conventional membrane-electrode assembly based on a Pt-Co alloy and a Nafion 115 membrane.

  1. Crosslinked wholly aromatic polyether membranes based on quinoline derivatives and their application in high temperature polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Kallitsis, K. J.; Nannou, R.; Andreopoulou, A. K.; Daletou, M. K.; Papaioannou, D.; Neophytides, S. G.; Kallitsis, J. K.

    2018-03-01

    An AB type difunctional quinoline based monomer bearing a pentafluorophenyl unit combined with a phenol functionality is being synthesized and homopolymerized to create linear aromatic polyethers as polymer electrolytes for HT-PEM FCs applications. Several conditions are tested for the optimized synthesis of the monomer and homopolymer. Additionally, covalent crosslinking through aromatic polyether bond formation enables the creation of wholly aromatic crosslinked polymeric electrolyte membranes. More specifically, the perfluorophenyl units are crosslinked with other hydroxyl end functionalized moieties, providing membranes with enhanced chemical and mechanical properties that are moreover easily doped with phosphoric acid even at ambient temperatures. All membranes are evaluated for their structural and thermal characteristics and their doping ability with phosphoric acid. Selected crosslinked membranes are further tested in terms of their single cell performance at the temperature range 160 °C-200 °C showing promising performance and high conductivity values even up to 0.2 S cm-1 in some cases.

  2. Preparation of anode-electrolyte structures using graphite, sodium bicarbonate or citric acid as pore forming agents for application in solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Paz Fiuza, Raigenis da; Silva, Marcos Aurelio da; Guedes, Bruna C.; Pontes, Luiz A.; Boaventura, Jaime Soares [UFBA, Salvador, Bahia (Brazil). Energy and Materials Science Group

    2010-07-01

    Cermets based on Ni supported on YSZ or GDC were prepared for use as anode in direct reform SOFCs. NaHCO3 (Na-Ni-YSZ and Na-Ni-GDC) or citric acid (Ac-Ni-YSZ and Ac-Ni-GDC) were used as pore forming agents (PFAs). The SOFC anode was also prepared using graphite (G-Ni-YSZ and G-Ni-GDC) as PFA for the purposes of comparison. The testing unitary SOFC, planar type, was made by pressing the anode-electrolyte assembly, followed by sintering at 1500 C. After this, LSM (lanthanum and strontium manganite) paint was used for the cathode deposition. The powdered cermets were evaluated in ethanol steam reforming at 650 C. The ethanol conversion was 84% and 32% for cermets Na-Ni-YSZ and G-Ni-YSZ, respectively and the selectivity to H{sub 2} was 32 and 20% for the two cermets, respectively. The Na-Ni-YSZ cermet was ten times more resistant to carbon deposition than the G-Ni-YSZ cermet. SEM micrographs of the anode-electrolyte assembly showed that the use of NaHCO{sub 3} as PFA created a well formed interface between layers with homogeneously distributed pores. In contrast, graphite as PFA formed a loose interface between anode and electrolyte. The performance of the unitary SOFC was evaluated using ethanol, hydrogen or methane as fuel. The cell operated well using any of these fuels; however, they exhibited different electrochemical behavior. (orig.)

  3. Development of anionic membranes produced by radiation-grafting for alkaline fuel cell applications; Desenvolvimento de membranas aniônicas obtidas por enxertia via irradiação para aplicação em células a combustível alcalinas

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Clotilde Coppini

    2017-07-01

    Anion Exchange Membranes (AEMs) are a promising alternative to the development of more efficient electrolytes for alkaline fuel cells. In general, the AEMs are ionomeric membranes able to conduct hydroxide ions (OH{sup -}) due to the quaternary ammonium groups, which confer high pH equivalent to the AEM. In order to develop alkaline membranes with high chemical and thermal stability, besides satisfactory ionic conductivity for alkaline fuel cells, membranes based on low density polyethylene (LDPE), ultrahigh weight molecular weight polyethylene (UHWHPE), poly(ethylene-co-tetrafluoroethylene) (PETFE) and poly(hexafluoropropylene-co-tetrafluoroethylene) (PFEP) previously irradiated by using {sup 60}Co gamma and electron beam sources, have been synthesized by styrene-grafting, and functionalized with trimethylamine to introduced quaternary ammonium groups. The resulting membranes were characterized by electron paramagnetic resonance (EPR), Raman spectroscopy, thermogravimetry (TG) and electrochemical impedance spectroscopy (EIS). The determination of the grafting degree and water uptake were conducted by gravimetry and ion exchange capacity, by titration. The membranes synthesized with PELD and PEUHMW polymers pre-irradiated at 70 kGy and stored at low temperature (-70 deg C), up to 10 months, showed ionic conductivity results, in hydroxide form (OH{sup -}), of 29 mS.cm{sup -1} and 14 mS.cm{sup -1} at 65 deg C, respectively. The PFEP polymers irradiated by the simultaneous process showed insufficient grating levels for the membrane synthesis, requiring more studies to improve the irradiation and grafting process. The styrene-grafted PETFE membranes, pre-irradiated at 70 kGy and stored at low temperature (-70 deg C), up to 10 months, showed ionic conductivity results, in hydroxide form (OH{sup -}), of 90 mS.cm{sup -1} to 165 mS.cm{sup -1}, in the temperature range 30 to 60 deg C. Such results have demonstrated that LDPE, UHMWPE and PETFE based AEMs are promising

  4. Highly dispersed TaOx nanoparticles prepared by electrodeposition as oxygen reduction electrocatalysts for polymer electrolyte fuel cells

    KAUST Repository

    Seo, Jeongsuk

    2013-06-06

    Based on the chemical stability of group IV and V elements in acidic solutions, TaOx nanoparticles prepared by electrodeposition in an ethanol-based Ta plating bath at room temperature were investigated as novel nonplatinum electrocatalysts for the oxygen reduction reaction (ORR) in polymer electrolyte fuel cells (PEFCs). Electrodeposition conditions of Ta complexes and subsequent various heat treatments for the deposited TaOx were examined for the best performance of the ORR. TaOx particles on carbon black (CB), electrodeposited at a constant potential of -0.5 V Ag/AgCl for 10 s and then heat-treated by pure H2 flow at 523 K for 1 h, showed excellent catalytic activity with an onset potential of 0.93 VRHE (for 2 μA cm-2) for the ORR. Surface characterizations of the catalysts were performed by scanning transmission electron microscopy (STEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDS). The loading amounts of the electrodeposited material on the CB were determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES). All the physical results suggested that high dispersion of TaOx particles on the CB surface with 2-3 nm size was critical and key for high activity. The chemical identity and modified surface structure for the deposited TaOx catalysts before and after H 2 heat treatment were analyzed by X-ray photoelectron spectroscopy (XPS). The formation of more exposed active sites on the electrode surface and enhanced electroconductivity of the tantalum oxide promoted from the H 2 treatment greatly improved the ORR performance of the electrodeposited TaOx nanoparticles on CB. Finally, the highly retained ORR activity after an accelerated durability test in an acidic solution confirmed and proved the chemical stability of the oxide nanoparticles. The high utilization of the electrodeposited TaOx nanoparticles uniformly dispersed on CB for the ORR was comparable to that of commercial Pt/CB catalysts

  5. Commercialization of fuel-cells

    Energy Technology Data Exchange (ETDEWEB)

    Penner, S.S.; Appleby, A.J.; Baker, B.S.; Bates, J.L.; Buss, L.B.; Dollard, W.J.; Farris, P.J.; Gillis, E.A.; Gunsher, J.A.; Khandkar, A.; Krumpelt, M.; O' Sullivan, J.B.; Runte, G.; Savinell, R.F.; Selman, J.R.; Shores, D.A.; Tarman, P.

    1995-03-01

    This report is an abbreviated version of the ''Report of the DOE Advanced Fuel Cell Commercialization Working Group (AFC2WG),'' released January 1995. We describe fuel-cell commercialization for stationary power applications of phosphoric acid, molten carbonate, solid oxide, and polymer electrolyte membrane fuel cells.

  6. A direct ascorbate fuel cell with an anion exchange membrane

    Science.gov (United States)

    Muneeb, Omar; Do, Emily; Tran, Timothy; Boyd, Desiree; Huynh, Michelle; Ghosn, Gregory; Haan, John L.

    2017-05-01

    Ascorbic Acid (Vitamin C) is investigated as a renewable alternative fuel for alkaline direct liquid fuel cells (DLFCs). The environmentally- and biologically-friendly compound, L-ascorbic acid (AA) has been modeled and studied experimentally under acidic fuel cell conditions. In this work, we demonstrate that ascorbic acid is a more efficient fuel in alkaline media than in acidic media. An operating direct ascorbate fuel cell is constructed with the combination of L-ascorbic acid and KOH as the anode fuel, air or oxygen as the oxidant, a polymer anion exchange membrane, metal or carbon black anode materials and metal cathode catalyst. Operation of the fuel cell at 60 °C using 1 M AA and 1 M KOH as the anode fuel and electrolyte, respectively, and oxygen gas at the cathode, produces a maximum power density of 73 mW cm-2, maximum current density of 497 mA cm-2 and an open circuit voltage of 0.90 V. This performance is significantly greater than that of an ascorbic acid fuel cell with a cation exchange membrane, and it is competitive with alkaline DLFCs fueled by alcohols.

  7. Intermediate Temperature Fuel Cell Using CsH2PO4/ZrO2-Based Composite Electrolytes

    DEFF Research Database (Denmark)

    Jensen, Annemette Hindhede; Li, Qingfeng; Christensen, Erik

    2014-01-01

    Proton conductors operating at intermediate temperatures are receiving significant attention due to their advantages over conventionally used materials in proton exchange membrane fuel cells. CsH2PO4 has proven to be proton conducting above 230°C, however within a narrow temperature range of the ...... to 280°C under low atmospheric humidification. Higher open circuit voltage and stability in the extended temperature range were achieved with composite electrolytes with a CsH2PO4 to ZrO2 molar ratio of 2....

  8. Determining the platinum loading and distribution of industrial scale polymer electrolyte membrane fuel cell electrodes using low energy X-ray imaging

    DEFF Research Database (Denmark)

    Holst, T.; Vassiliev, Anton; Kerr, R.

    2014-01-01

    Low energy X-ray imaging (E <25 keV) is herein demonstrated to be a rapid, effective and non-destructive tool for the quantitative determination of the platinum loading and distribution over the entire geometric area of gas diffusion electrodes for polymer electrolyte membrane fuel cells. A linea...... of electrodes fabricated using an industrial spraying process. This technique proves to be an attractive option for the electrode performance study, the process optimization and quality control of electrode fabrication on an industrial scale....

  9. Achievement report for fiscal 1997 on research and development of solid electrolyte fuel cells; Kotai denkaishitsugata nenryo denchi no kenkyu kaihatsu 1997 nendo seika hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-07-01

    This paper describes the achievements in fiscal 1997 on research and development of solid electrolyte fuel cells. Fuji Electric has demonstrated possibilities of film type cells of predominantly metallic flat plate supporting type of a large-area cell lamination system, and seal-less stack structure. Sanyo Electric has discussed making thinner the composite cell lamination type anode, optimization in sintering temperature, and sealing materials. The Fine Ceramic Center has performed a 1,000-hour test on an La(Sr) MnO{sub 3}-YSZ electrode, in which A-site defect amount was decreased to 0.1-0.02 to stabilize micro-structure air electrodes for an extended period of time. Fujikura has discussed functional materials for high dispersion and slanting in a fuel electrode Ni/YSZ. Mitsubishi Heavy Industries has fabricated MgO-based fuel electrodes on a trial basis, and performed internal reformation and power generation tests by using full-size stacks. Murata Manufacturing Company has verified long-term power generation properties and stability of a three-layered co-sintered film of flat plate type. Mitsui Shipbuilding has reached a near final conclusion on the basic structure of gas separator cells. The Central Electric Power Research Institute has completed a conceptual design on a 300-MW class composite power generation system in which SOFC and gas turbines are combined. The Electric Power Development Company has discussed problems in SOFC composite power generation development using coal gasified fuel. (NEDO)

  10. Development of a Novel Home Cogeneration System using a Polymer Electrolyte Fuel Cell which Enabled Air Conditioning by Its Low-TemperatureWaste Heat

    Science.gov (United States)

    Nishimura, Nobuya; Honda, Kuniaki; Kawakami, Ryuichiro; Nishikawa, Toshimichi; Iyota, Hiroyuki; Nomura, Tomohiro

    Micro-scale distributed power generation system, which means a micro-cogeneration system in almost cases, has been paid a great attention from a standpoint of saving fossil fuels' consumption and preventing global warming. Especially, polymer electrolyte fuel cell (PEFC) is considered the most promising power generation system for small scale commercial use and residential use. In the PEFC cogeneration system, small amount of waste heat at low temperature from a cell stack is almost used to produce hot water. Therefore, in the paper, we proposed a new heat utilization method of the waste heat for air conditioning. In the proposed home cogeneration system, absorption refrigerator is introduced in order to produce chilled water. Thermal performances of the proposed system have been analyzed by a computer simulation which was developed for the prediction both of power generation characteristics of PEFC and absorption refrigerator's behavior.

  11. Alkaline galvanic cells

    Energy Technology Data Exchange (ETDEWEB)

    Eisenberg, M.

    1993-06-01

    A battery is described having an anode, a cathode and an electrolyte with the anode having zinc or a zinc alloy as an active anodic material, the cathode having a metal oxide or hydroxide as an active cathodic material, and the electrolyte comprising a solution of a first salt formed by the reaction of one or more acids selected from the group consisting of boric acid, phosphoric acid and arsenic acid with an alkali or earth alkali hydroxide present in an amount to produce a stoichiometric, excess of said hydroxide to said acid in the range of 2.5 to 11.0 equivalents per liter, and a solution of a second salt which is a soluble alkali or earth alkali fluoride in an amount corresponding to a concentration range of 0.01 to 1.0 equivalents per liter of total solution.

  12. Stable proton-conducting Ca-doped LaNbO4 thin electrolyte-based protonic ceramic membrane fuel cells by in situ screen printing

    International Nuclear Information System (INIS)

    Lin Bin; Wang Songlin; Liu Xingqin; Meng Guangyao

    2009-01-01

    In order to develop a simple and cost-effective route to fabricate protonic ceramic membrane fuel cells (PCMFCs), a stable proton-conducting La 0.99 Ca 0.01 NbO 4 (LCN) thin electrolyte was fabricated on a porous NiO-La 0.5 Ce 0.5 O 1.75 (NiO-LDC) anode by in situ screen printing. The key part of this process is to directly print well-mixed ink of La 2 O 3 , CaCO 3 and Nb 2 O 5 instead of pre-synthesized LCN ceramic powder on the anode substrate. After sintering at 1400 deg. C for 5 h, the full dense electrolyte membrane in the thickness of 20 μm was obtained. A single cell was assembled with (La 0.8 Sr 0.2 ) 0.9 MnO 3-δ -La 0.5 Ce 0.5 O 1.75 (LSM-LDC) as cathode and tested with humidified hydrogen as fuel and static air as oxidant. The open circuit voltage (OCV) and maximum power density respectively reached 0.98 V and 65 mW cm -2 at 800 deg. C. Interface resistance of cell under open circuit condition was also investigated.

  13. Effects of clamping force on the water transport and performance of a PEM (proton electrolyte membrane) fuel cell with relative humidity and current density

    International Nuclear Information System (INIS)

    Cha, Dowon; Ahn, Jae Hwan; Kim, Hyung Soon; Kim, Yongchan

    2015-01-01

    The clamping force should be applied to a proton electrolyte membrane (PEM) fuel cell due to its structural characteristics. The clamping force affects the ohmic and mass transport resistances in the PEM fuel cell. In this study, the effects of the clamping force on the water transport and performance characteristics of a PEM fuel cell are experimentally investigated with variations in the relative humidity and current density. The water transport characteristics were analyzed by calculating the net drag coefficient. The ohmic resistance decreased with the increase in the clamping force due to the reduced contact resistance and more even membrane hydration. However, the mass transport resistance increased with the increase in the clamping force due to the gas diffusion layer compression. The net drag coefficient decreased with the increase in the clamping force due to high water back-diffusion. Additionally, the relationship between the total resistance and the net drag coefficient was investigated. - Highlights: • Effects of clamping force on the performance of a PEM fuel cell are investigated. • Water transport characteristics are analyzed using net drag coefficient. • Ohmic resistance decreased with clamping force, but mass transport resistance increased. • Net drag coefficient decreased with the increase in clamping force. • Total resistance was significantly degraded for a net drag coefficient below 0.2.

  14. Fuel cell system with interconnect

    Energy Technology Data Exchange (ETDEWEB)

    Goettler, Richard; Liu, Zhien

    2017-12-12

    The present invention includes a fuel cell system having a plurality of adjacent electrochemical cells formed of an anode layer, a cathode layer spaced apart from the anode layer, and an electrolyte layer disposed between the anode layer and the cathode layer. The fuel cell system also includes at least one interconnect, the interconnect being structured to conduct free electrons between adjacent electrochemical cells. Each interconnect includes a primary conductor embedded within the electrolyte layer and structured to conduct the free electrons.

  15. Fuel cell systems

    International Nuclear Information System (INIS)

    Kotevski, Darko

    2003-01-01

    Fuel cell systems are an entirely different approach to the production of electricity than traditional technologies. They are similar to the batteries in that both produce direct current through electrochemical process. There are six types of fuel cells each with a different type of electrolyte, but they all share certain important characteristics: high electrical efficiency, low environmental impact and fuel flexibility. Fuel cells serve a variety of applications: stationary power plants, transport vehicles and portable power. That is why world wide efforts are addressed to improvement of this technology. (Original)

  16. Hydrocarbon-based fuel cell membranes: Sulfonated crosslinked poly(1,3-cyclohexadiene) membranes for high temperature polymer electrolyte fuel cells

    OpenAIRE

    Deng, Suxiang; Hassan, Mohammad K.; Mauritz, Kenneth A.; Mays, Jimmy W.

    2015-01-01

    High temperature fuel cell membranes based on poly(1,3-cyclohexadiene) were prepared by a Polymerization-Crosslinking-Sulfonation (PCS) approach, and a broad range of membrane compositions were achieved using various sulfonating reagents and reaction conditions. Membranes were characterized for their proton conductivity and thermal degradation behavior. Some of the membranes showed up to a 68% increase in proton conductivity as compared to Nafion under the same conditions (100% relative humid...

  17. Phenolphthalein-based Poly(arylene ether sulfone nitrile)s Multiblock Copolymers As Anion Exchange Membranes for Alkaline Fuel Cells.

    Science.gov (United States)

    Lai, Ao Nan; Wang, Li Sha; Lin, Chen Xiao; Zhuo, Yi Zhi; Zhang, Qiu Gen; Zhu, Ai Mei; Liu, Qing Lin

    2015-04-22

    A series of phenolphthalein-based poly(arylene ether sulfone nitrile)s (PESN) multiblock copolymers containing 1-methylimidazole groups (ImPESN) were synthesized to prepare anion exchange membranes (AEMs) for alkaline fuel cells. The ion groups were introduced selectively and densely on the unit of phenolphthalein as the hydrophilic segments, allowing for the formation of ion clusters. Strong polar nitrile groups were introduced into the hydrophobic segments with the intention of improving the dimensional stability of the AEMs. A well-controlled multiblock structure was responsible for the well-defined hydrophobic/hydrophilic phase separation and interconnected ion-transport channels, as confirmed by atomic force microscopy and small angle X-ray scattering. The ImPESN membranes with low swelling showed a relatively high water uptake, high hydroxide ion conductivity together with good mechanical, thermal and alkaline stability. The ionic conductivity of the membranes was in the range of 3.85-14.67×10(-2) S·cm(-1) from 30 to 80 °C. Moreover, a single H2/O2 fuel cell with the ImPESN membrane showed an open circuit voltage of 0.92 V and a maximum power density of 66.4 mW cm(-2) at 60 °C.

  18. Synthesis and characterization of high performing Fe-N-C catalyst for oxygen reduction reaction (ORR) in Alkaline Exchange Membrane Fuel Cells

    Science.gov (United States)

    Hossen, Md Mosaddek; Artyushkova, Kateryna; Atanassov, Plamen; Serov, Alexey

    2018-01-01

    In this article, three different Fe-N-C oxygen reduction reaction (ORR) catalysts derived from different organic molecules i.e. Fe-NMG, Fe-NMP, Fe-MBZ have been synthesized, characterized by physical-chemical methods and studied in the reaction of oxygen reduction (ORR). It is found that Fe-NMG shows higher ORR performance than Fe-NMP and Fe-MBZ, by both rotating ring disk electrode (RRDE) and fuel cell tests. From characterization and surface analysis, it can be explained that the presence of higher amount of surface oxides and pyridinic nitrogen is the main reason for better performance towards ORR in alkaline media. To achieve the highest performance in alkaline exchange membrane fuel cell (AEMFC), the optimization of catalyst layer composition using various concentrations of ionomer (Tokuyama, AS4) was performed. At the optimum cathode layer configuration utilizing Fe-NMG produces the peak power density of 218 mWcm-2, which is one of the highest values presented in the open literature.

  19. Electrocatalytic oxidation of meso-erythritol in anion-exchange membrane alkaline fuel cell on PdAg/CNT catalyst

    Science.gov (United States)

    Benipal, Neeva; Qi, Ji; McSweeney, Ryan F.; Liang, Changhai; Li, Wenzhen

    2018-01-01

    C-C bond cleavage during electrocatalytic oxidation of glycerol and C3+ polyols often occurs and can significantly affect the Faradaic efficiency, fuel utilization, and output power density of a direct polyol fuel cell, although this has not been deeply investigated. With the goal of acquiring new knowledge of C-C bond breaking of polyols, this study examines the electrocatalytic oxidation of a C4 polyol meso-erythritol on carbon nanotube supported Pd-based catalysts (Pd/CNT, PdAg/CNT, and PdAg3/CNT) in an anion-exchange membrane fuel cell (AEMFC). Our results show that PdAg/CNT improves the fuel efficiency of meso-erythritol oxidation by contributing to the C-C bond cleavage of meso-erythritol in C3 and C2 chemicals. Based on the analysis of electro-oxidation products and half-cell cyclic voltammetry (CV) of intermediates, a meso-erythritol electro-oxidation pathway has been proposed to demonstrate that Ag is likely to assist Pd to promote the cleavage of C-C bonds of meso-erythritol.

  20. A review on polymer electrolyte membrane fuel cell catalyst degradation and starvation issues: Causes, consequences and diagnostic for mitigation

    Science.gov (United States)

    Yousfi-Steiner, N.; Moçotéguy, Ph.; Candusso, D.; Hissel, D.

    In proton exchange membrane fuel cells, cost, reliability and durability are important issues that need to be solved before their commercialization. Their performance decrease during operation is attributed, amongst others, to the loss of electrochemical surface area occurring during long-term ageing, after transients or after an incident (faulty operation). These losses are mainly due to catalyst metal degradation and carbon-support corrosion, which are continuous irreversible processes that can dramatically reduce the fuel cell lifetime. In this paper, the phenomena linked to catalyst and carbon-support degradation are reviewed, focusing on those caused by fuel and oxidant starvation, since these faulty conditions are amongst the most critical for fuel cell durability. A description of reactions potentially involved in the catalyst degradation, associated with thermodynamic and kinetic considerations related to fuel cell operation are reviewed. This information is used to interpret the experimental results presented in the literature and reviewed in this paper. Based on these reviews, an analysis of the "reverse decay current mechanism" is performed and an alternative mechanism is suggested together with an experiment that would identify the most likely between them. Finally, some characterization methods or mitigation strategies are listed and an illustrative fault tree is built, pointing out the relationship between causes and symptoms in catalyst degradation.

  1. A review on polymer electrolyte membrane fuel cell catalyst degradation and starvation issues: Causes, consequences and diagnostic for mitigation

    Energy Technology Data Exchange (ETDEWEB)

    Yousfi-Steiner, N. [EIFER, European Institute For Energy Research, Emmy-Noether Strasse 11, 76131 Karlsruhe (Germany); FEMTO-ST/ENISYS FCLAB, UMR CNRS 6174, University of Franche-Comte, rue Mieg, 90010 Belfort cedex (France); Mocoteguy, Ph. [EIFER, European Institute For Energy Research, Emmy-Noether Strasse 11, 76131 Karlsruhe (Germany); Candusso, D. [INRETS/FCLAB, The French National Institute for Transport and Safety Research, rue Mieg, 90010 Belfort cedex (France); FEMTO-ST/ENISYS FCLAB, UMR CNRS 6174, University of Franche-Comte, rue Mieg, 90010 Belfort cedex (France); Hissel, D. [FEMTO-ST/ENISYS FCLAB, UMR CNRS 6174, University of Franche-Comte, rue Mieg, 90010 Belfort cedex (France)

    2009-10-20

    In proton exchange membrane fuel cells, cost, reliability and durability are important issues that need to be solved before their commercialization. Their performance decrease during operation is attributed, amongst others, to the loss of electrochemical surface area occurring during long-term ageing, after transients or after an incident (faulty operation). These losses are mainly due to catalyst metal degradation and carbon-support corrosion, which are continuous irreversible processes that can dramatically reduce the fuel cell lifetime. In this paper, the phenomena linked to catalyst and carbon-support degradation are reviewed, focusing on those caused by fuel and oxidant starvation, since these faulty conditions are amongst the most critical for fuel cell durability. A description of reactions potentially involved in the catalyst degradation, associated with thermodynamic and kinetic considerations related to fuel cell operation are reviewed. This information is used to interpret the experimental results presented in the literature and reviewed in this paper. Based on these reviews, an analysis of the ''reverse decay current mechanism'' is performed and an alternative mechanism is suggested together with an experiment that would identify the most likely between them. Finally, some characterization methods or mitigation strategies are listed and an illustrative fault tree is built, pointing out the relationship between causes and symptoms in catalyst degradation. (author)

  2. Simple electrolytic cell for production of elemental fluorine

    International Nuclear Information System (INIS)

    Dides F, M.; Padilla S, U.

    1990-01-01

    It was constructed and tested a simple electrolytic cell for the production of elemental fluorine. The fluorine production is essential in the obtainment of uranium hexafluoride, a compound for the nuclear fuel cycle. (A.C.A.S.)

  3. Synthesis and electrochemical characterization of hybrid membrane Nafion-SiO2 for application as polymer electrolyte in PEM fuel cell

    International Nuclear Information System (INIS)

    Dresch, Mauro Andre

    2009-01-01

    In this work, the effect of sol-gel synthesis parameters on the preparation and polarization response of Nafion-SiO 2 hybrids as electrolytes for proton exchange membrane fuel cells (PEMFC) operating at high temperatures (130 degree C) was evaluated. The inorganic phase was incorporated in a Nafion matrix with the following purposes: to improve the Nafion water uptake at high temperatures (> 100 degree C); to increase the mechanical strength of Nafion and; to accelerate the electrode reactions. The hybrids were prepared by an in-situ incorporation of silica into commercial Nafion membranes using an acid-catalyzed sol-gel route. The effects of synthesis parameters, such as catalyst concentration, sol-gel solvent, temperature and time of both hydrolysis and condensation reactions, and silicon precursor concentration (Tetraethyl orthosilicate - TEOS), were evaluated as a function on the incorporation degree and polarization response. Nafion-SiO 2 hybrids were characterized by gravimetry, thermogravimetric analysis (TGA), scanning electron microscopy and X-ray dispersive energy (SEM-EDS), electrochemical impedance spectroscopy (EIS), and X-ray small angle scattering (SAXS). The hybrids were tested as electrolyte in single H 2 /O 2 fuel cells in the temperature range of 80 - 130 degree C and at 130 degree C and reduced relative humidity (75% and 50%). Summarily, the hybrid performance showed to be strongly dependent on the synthesis parameters, mainly, the type of alcohol and the TEOS concentration. (author)

  4. Proton conductivity and fuel cell property of composite electrolyte consisting of Cs-substituted heteropoly acids and sulfonated poly(ether-ether ketone)

    Energy Technology Data Exchange (ETDEWEB)

    Oh, S.Y.; Yoshida, T.; Kawamura, G.; Sakai, M.; Matsuda, A. [Department of Materials Science, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan); Muto, H. [Department of Materials Science and Engineering, Kurume National College of Technology, 1-1-1 Komorino, Kurume, Fukuoka 830-8555 (Japan)

    2010-09-15

    Inorganic-organic composite electrolytes were fabricated from partially Cs{sup +}-substituted heteropoly acids (Cs-HPAs) and sulfonated poly(ether-ether ketone) (SPEEK) for application in fuel cells. Heteropoly acids, such as phosphotungstic acid (H{sub 3}PW{sub 12}O{sub 40}:WPA), and silicotungstic acid (H{sub 4}SiW{sub 12}O{sub 40}:WSiA), were mechanochemically treated with cesium hydrogen sulfate (CsHSO{sub 4}) to obtain the form of Cs-HPAs. SPEEK was prepared from PEEK by sulfonation using concentrated sulfuric acid. Water durability and surface structure of HPAs were modified by introducing Cs{sup +} into HPAs. Flexible and hot water stable composite electrolytes were obtained, and their electrochemical properties were markedly improved with the addition of Cs-HPAs into the SPEEK matrix. Maximum power densities of 245 and 247 mW cm{sup -2} were obtained for 50WPA.50CsHSO{sub 4} and 50WSiA.50CsHSO{sub 4} in SPEEK (1/5 by weight) composite electrolytes, respectively, from single cell tests at 80 C and 80 RH%. These results suggest that a three-dimensional proton-conductive path was formed among homogeneously distributed Cs-HPAs particles in the SPEEK matrix. The Cs-HPAs incorporated into the SPEEK matrix increased the number of protonate sites in the electrolyte. These observations imply that the mechanochemically synthesized Cs-HPAs, which consist of hydrogen bondings between Cs-HPAs and -HSO{sub 4}{sup -}, dissociated from CsHSO{sub 4}, are promising materials as inorganic fillers in inorganic-organic composite. (author)

  5. Constant strength fuel-fuel cell

    International Nuclear Information System (INIS)

    Vaseen, V.A.

    1980-01-01

    A fuel cell is an electrochemical apparatus composed of both a nonconsumable anode and cathode; and electrolyte, fuel oxidant and controls. This invention guarantees the constant transfer of hydrogen atoms and their respective electrons, thus a constant flow of power by submergence of the negative electrode in a constant strength hydrogen furnishing fuel; when said fuel is an aqueous absorbed hydrocarbon, such as and similar to ethanol or methnol. The objective is accomplished by recirculation of the liquid fuel, as depleted in the cell through specific type membranes which pass water molecules and reject the fuel molecules; thus concentrating them for recycle use

  6. Influence of Silica/Sulfonated Polyether-Ether Ketone as Polymer Electrolyte Membrane for Hydrogen Fueled Proton Exchange Membrane Fuel Cells

    Directory of Open Access Journals (Sweden)

    Sri Handayani

    2011-12-01

    Full Text Available The operation of non-humidified condition of proton exchange membrane fuel cell (PEMFC using composite sPEEK-silica membrane is reported. Sulfonated membrane of PEEK is known as hydrocarbon polyelectrolyte membrane for PEMFC and direct methanol fuel cell (DMFC. The state of the art of fuel cells is based on the perluorosulfonic acid membrane (Nafion. Nafion has been the most used in both PEMFC and DMFC due to good performance although in low humidified condition showed poor current density. Here we reported the effect of silica in hydrocarbon sPEEK membrane that contributes for a better water management system inside the cell, and showed 0.16 W/cm2 of power density which is 78% higher than that of non-silica modified [Keywords: composite membrane, polyether-ether ketone, silica, proton exchange membrane fuel cell].

  7. A review of cell-scale multiphase flow modeling, including water management, in polymer electrolyte fuel cells

    International Nuclear Information System (INIS)

    Andersson, M.; Beale, S.B.; Espinoza, M.; Wu, Z.; Lehnert, W.

    2016-01-01

    Highlights: • The transport expressions inside PEFC GDLs are developed to describe significantly different systems. • Insight into the fundamental processes of liquid water evolution and transport in the GDL and GC is still lacking. • One important feature is the possibility to track the front between the liquid and the gas phases. • The two phase micro channels pressure drop correlations may not be applicable for GCs since one wall being porous. - Abstract: The PEFC has emerged as the most viable fuel cell type for automotive and some portable applications, and also has potential back-up power unit applications due to its low operating temperature, comparative simplicity of construction, high power density, and ease of operation. In spite of tremendous scientific advances, as well as engineering progress over the last few decades, the commercialization of PEFCs remains unrealized, owing primarily to economic viability associated with the high prices of materials and components and technical problems relating primarily to water management. The difficulty in addressing the water management issues lies mostly in the two-phase multi-component flow involving phase-change in porous media, coupled heat and mass transfer, interactions between the porous layers and gas channel (GC) and the complex relationship between water content and cell performance. Due to the low temperature of operation, water generated by the electrochemical reactions often condenses into liquid form, potentially flooding the gas diffusion layer (GDL), GC or other components. Insight into the fundamental processes of liquid water evolution and transport is still lacking, preventing further enhanced PEFC development. The aim of this paper is to give a comprehensive introduction to PEFC modeling inside GCs and GDLs, with a focus on two-phase flow and related phase-change and transport processes. Relevant momentum, mass and heat transport processes are introduced and the microstructural effects

  8. The Synthesis and Characterization of Ionic Liquids for Alkali-Metal Batteries and a Novel Electrolyte for Non-Humidified Fuel Cells

    Science.gov (United States)

    Tucker, Telpriore G.

    This thesis focused on physicochemical and electrochemical projects directed towards two electrolyte types: 1) class of ionic liquids serving as electrolytes in the catholyte for alkali-metal ion conduction in batteries and 2) gel membrane for proton conduction in fuel cells; where overall aims were encouraged by the U.S. Department of Energy. Large-scale, sodium-ion batteries are seen as global solutions to providing undisrupted electricity from sustainable, but power-fluctuating, energy production in the near future. Foreseen ideal advantages are lower cost without sacrifice of desired high-energy densities relative to present lithium-ion and lead-acid battery systems. Na/NiCl2 (ZEBRA) and Na/S battery chemistries, suffer from high operation temperature (>300ºC) and safety concerns following major fires consequent of fuel mixing after cell-separator rupturing. Initial interest was utilizing low-melting organic ionic liquid, [EMI+][AlCl 4-], with well-known molten salt, NaAlCl4, to create a low-to-moderate operating temperature version of ZEBRA batteries; which have been subject of prior sodium battery research spanning decades. Isothermal conductivities of these electrolytes revealed a fundamental kinetic problem arisen from "alkali cation-trapping effect" yet relived by heat-ramping >140ºC. Battery testing based on [EMI+][FeCl4 -] with NaAlCl4 functioned exceptional (range 150-180ºC) at an impressive energy efficiency >96%. Newly prepared inorganic ionic liquid, [PBr4+][Al2Br7-]:NaAl2Br 7, melted at 94ºC. NaAl2Br7 exhibited super-ionic conductivity 10-1.75 Scm-1 at 62ºC ensued by solid-state rotator phase transition. Also improved thermal stability when tested to 265ºC and less expensive chemical synthesis. [PBr4 +][Al2Br7-] demonstrated remarkable, ionic decoupling in the liquid-state due to incomplete bromide-ion transfer depicted in NMR measurements. Fuel cells are electrochemical devices generating electrical energy reacting hydrogen/oxygen gases

  9. In Operando Quantification of Three-Dimensional Water Distribution in Nanoporous Carbon-Based Layers in Polymer Electrolyte Membrane Fuel Cells.

    Science.gov (United States)

    Alrwashdeh, Saad S; Manke, Ingo; Markötter, Henning; Klages, Merle; Göbel, Martin; Haußmann, Jan; Scholta, Joachim; Banhart, John

    2017-06-27

    Understanding the function of nanoporous materials employed in polymer electrolyte membrane fuel cells (PEMFCs) is crucial to improve their performance, durability, and cost efficiency. Up to now, the water distribution in the nm-sized pore structures was hardly accessible during operation of the cells. Here we demonstrate that phase contrast synchrotron X-ray tomography allows for an in operando quantification of the three-dimensional water distribution within the nm-sized pores of carbon-based microporous layers (MPLs). For this purpose, a fuel cell design optimized for tomographic phase contrast measurements was realized. Water in the pores of the entire MPL was detected and quantified. We found an inhomogeneous distribution of the local water saturation and a sharp boundary between mostly filled MPL and almost empty areas. We attribute the latter observation to the two-phase boundary created because condensation takes place predominantly on one side of the boundary. Furthermore, high water saturation in large areas hints at gas diffusion or transport along preferred three-dimensional paths through the material, therefore bypassing most of the MPL volume. Our approach may contribute significantly to future investigations of nanoporous fuel cell materials under realistic operating conditions.

  10. Comparison of Numerical and Experimental Studies for Flow-Field Optimization Based on Under-Rib Convection in Polymer Electrolyte Membrane Fuel Cells

    Directory of Open Access Journals (Sweden)

    Nguyen Duy Vinh

    2016-10-01

    Full Text Available The flow-field design based on under-rib convection plays an important role in enhancing the performance of polymer electrolyte membrane fuel cells (PEMFCs because it ensures the uniform distribution of the reacting gas and the facilitation of water. This research focused on developing suitable configurations of the anode and cathode bipolar plates to enhance the fuel cell performance based on under-rib convection. The work here evaluated the effects of flow-field designs, including a serpentine flow field with sub channel and by pass and a conventional serpentine flow-field on single-cell performance. Both the experiment and computer simulation indicated that the serpentine flow field with sub channel and by pass (SFFSB configuration enables more effective utilization of the electrocatalysts since it improves reactant transformation rate from the channel to the catalyst layer, thereby dramatically improving the fuel cell performance. The simulation and experimental results indicated that the power densities are increased by up to 16.74% and 18.21%, respectively, when applying suitable flow-field configurations to the anode and cathode bipolar plates. The findings in this are the foundation for enhancing efficient PEMFCs based on flow field design.

  11. Three-dimensional dynamic modelling of Polymer-Electrolyte-Membrane-Fuel-Cell-Systems; Dreidimensionale dynamische Modellierung und Berechnung von Polymer-Elektrolyt-Membran-Brennstoffzellen

    Energy Technology Data Exchange (ETDEWEB)

    Vath, Andreas

    2008-12-15

    This thesis deals with dynamic and multi-dimensional modelling of Polymer- Electrolyte-Membrane-Fuel-Cells (PEMFC). The developed models include all the different layers of the fuel cell e.g. flow field, gas diffusion layer, catalyst layer and membrane with their particular physical, chemical and electrical characteristics. The simulation results have been verified by detailed measurements performed at the research centre for hydrogen and solar energy in Ulm (ZSW Ulm). The developed three dimensional model describes the time- and spatial-dependent charge and mass transport in a fuel cell. Additionally, this model allows the analysis of critical operating conditions. For example, the current density distribution for different membranes is shown during insufficient humidification which results in local overstraining and degradation. The model also allows to analyse extreme critical operating conditions, e.g. short time breakdown of the humidification. Furthermore, the model shows the available potential of improvement opportunities in power density and efficiency of PEMFC due to optimisation of the gas diffusion layer, the catalyst and membrane. In the second part of the work the application of PEMFC systems for combined heat and power units is described by one-dimensional models for an electrical power range between 1 kW and 5 kW. This model contains the necessary components, e.g. gas processing, humidification, gas supply, fuel cell stack, heat storage, pumps, auxiliary burner, power inverter und additional aggregates. As a main result, it is possible to distinctly reduce the energy demand and the carbon dioxide exhaust for different load profiles. Today the costs for fuel cell systems are considerably higher than that of the conventional electrical energy supply. (orig.)

  12. Cross-linked poly (vinyl alcohol)/sulfosuccinic acid polymer as an electrolyte/electrode material for H2-O2 proton exchange membrane fuel cells

    Science.gov (United States)

    Ebenezer, D.; Deshpande, Abhijit P.; Haridoss, Prathap

    2016-02-01

    Proton exchange membrane fuel cell (PEMFC) performance with a cross-linked poly (vinyl alcohol)/sulfosuccinic acid (PVA/SSA) polymer is compared with Nafion® N-115 polymer. In this study, PVA/SSA (≈5 wt. % SSA) polymer membranes are synthesized by a solution casting technique. These cross-linked PVA/SSA polymers and Nafion are used as electrolytes and ionomers in catalyst layers, to fabricate different membrane electrode assemblies (MEAs) for PEMFCs. Properties of each MEA are evaluated using scanning electron microscopy, contact angle measurements, impedance spectroscopy and hydrogen pumping technique. I-V characteristics of each cell are evaluated in a H2-O2 fuel cell testing fixture under different operating conditions. PVA/SSA ionomer causes only an additional ≈4% loss in the anode performance compared to Nafion ionomer. The maximum power density obtained from PVA/SSA based cells range from 99 to 117.4 mW cm-2 with current density range of 247 to 293.4 mA cm-2. Ionic conductivity of PVA/SSA based cells is more sensitive to state of hydration of MEA, while maximum power density obtained is less sensitive to state of hydration of MEA. Maximum power density of cross-linked PVA/SSA membrane based cell is about 35% that of Nafion® N-115 based cell. From these results, cross-linked PVA/SSA polymer is identified as potential candidate for PEMFCs.

  13. Fuel Exhaling Fuel Cell.

    Science.gov (United States)

    Manzoor Bhat, Zahid; Thimmappa, Ravikumar; Devendrachari, Mruthyunjayachari Chattanahalli; Kottaichamy, Alagar Raja; Shafi, Shahid Pottachola; Varhade, Swapnil; Gautam, Manu; Thotiyl, Musthafa Ottakam

    2018-01-18

    State-of-the-art proton exchange membrane fuel cells (PEMFCs) anodically inhale H 2 fuel and cathodically expel water molecules. We show an unprecedented fuel cell concept exhibiting cathodic fuel exhalation capability of anodically inhaled fuel, driven by the neutralization energy on decoupling the direct acid-base chemistry. The fuel exhaling fuel cell delivered a peak power density of 70 mW/cm 2 at a peak current density of 160 mA/cm 2 with a cathodic H 2 output of ∼80 mL in 1 h. We illustrate that the energy benefits from the same fuel stream can at least be doubled by directing it through proposed neutralization electrochemical cell prior to PEMFC in a tandem configuration.

  14. Electro-oxidation of ethylene glycol and glycerol at palladium-decorated FeCo@Fe core–shell nanocatalysts for alkaline direct alcohol fuel cells: functionalized MWCNT supports and impact on product selectivity

    CSIR Research Space (South Africa)

    Fashedemi, OO

    2015-04-01

    Full Text Available Half-cell reactions and alkaline direct ethylene glycol and glycerol fuel cells (DEGFC and DGFC) have been studied on Pd-based ternary core–shell (FeCo@Fe@Pd) nanocatalyst using multi-walled carbon nanotubes bearing carboxylic (MWCNT...

  15. Multi-Hybrid Power Vehicles with Cost Effective and Durable Polymer Electrolyte Membrane Fuel Cell and Li-ion Battery

    Energy Technology Data Exchange (ETDEWEB)

    Bose, Anima [Univ. of Houston, Houston, TX (United States)

    2014-02-28

    Anima Bose, the principal investigator of the project, originally proposed to develop composite membranes to operate PEMFCs at much higher temperatures than 80°C and to alleviate the flooding problems often encountered in Nafion menmbrane containing fuel cells. The PI has successfully created composite membranes by blending small quantities of octasilane-poss (OSP) with Nafion. The composite membranes exhibited temperature tolerance up to 110°C without scarifying cell performance as determined by polarization curves and proton conductivity measurements. These membranes also exhibited superior water management performance as evident from the lack of flooding. Furthermore, these fuel cells performed well under reduced humidities. Structural and thermal analyses revealed that these Nafion-octasilane composite membranes are homogenous at concentrations up to 3 wt% of the OSP and that the siloxane offers additional thermal stability.

  16. Compact Intermediate-Temperature Fuel Cells

    National Research Council Canada - National Science Library

    Sun, Yipeng

    2003-01-01

    In Phase I, we demonstrate the feasibility of making supported electronically insulating, proton conducting inorganic thin films on metal hydride foils for intermediate temperature fuel cell electrolytes...

  17. Localised electrochemical impedance measurements of a polymer electrolyte fuel cell using a reference electrode array to give cathode-specific measurements and examine membrane hydration dynamics

    Science.gov (United States)

    Engebretsen, Erik; Hinds, Gareth; Meyer, Quentin; Mason, Tom; Brightman, Edward; Castanheira, Luis; Shearing, Paul R.; Brett, Daniel J. L.

    2018-04-01

    Advances in bespoke diagnostic techniques for polymer electrolyte fuel cells continue to provide unique insight into the internal operation of these devices and lead to improved performance and durability. Localised measurements of current density have proven to be extremely useful in designing better fuel cells and identifying optimal operating strategies, with electrochemical impedance spectroscopy (EIS) now routinely used to deconvolute the various losses in fuel cells. Combining the two techniques provides another dimension of understanding, but until now each localised EIS has been based on 2-electrode measurements, composed of both the anode and cathode responses. This work shows that a reference electrode array can be used to give individual electrode-specific EIS responses, in this case the cathode is focused on to demonstrate the approach. In addition, membrane hydration dynamics are studied under current load steps from open circuit voltage. A three-stage process is identified associated with an initial rapid reduction in membrane resistance after 10 s of applying a current step, followed by a slower ramp to approximately steady state, which was achieved after ∼250 s. These results support previously published work that has looked at membrane swelling dynamics and reveal that membrane hydration/membrane resistance is highly heterogeneous.

  18. Impacts of Electrode Coating Irregularities on Polymer Electrolyte Membrane Fuel Cell Lifetime Using Quasi In-Situ Infrared Thermography and Accelerated Stress Testing

    Energy Technology Data Exchange (ETDEWEB)

    Bender, Guido [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Phillips, Adam [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Ulsh, Michael J [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Neyerlin, Kenneth C [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Porter, Jason [Colorado School of Mines

    2018-03-02

    In-line quality control diagnostics for roll-to-roll (R2R) manufacturing techniques will play a key role in the future commercialization of the polymer electrolyte membrane fuel cell (PEMFC) used in automotive applications. These diagnostics monitor the fabrication of the membrane electrode assembly (MEA), which detect and flag any non-uniformity that may potentially harm PEMFC performance and/or lifetime. This will require quantitative thresholds and a clear distinction between harmful defects and harmless coating irregularities. Thus, novel fuel cell hardware with quasi in-situ infrared (IR) thermography capabilities is utilized to understand how bare spots in the cathode electrode impact MEA lifetime. An accelerated stress test (AST) simulates chemical and mechanical degradation modes seen in vehicular operation. The actual open circuit voltage and rate of change of this voltage are used as in-situ indicators for MEA failure, enabling capture of the progression of failure point development. Bare spot coating irregularities located at the center of the electrode were found to have no impact on MEA lifetime when compared to a pristine MEA. However, MEA lifetime was found to be considerably shortened when these same irregularities are located at the cathode inlet and, especially, the anode inlet regions of the fuel cell.

  19. Solid Acid Based Fuel Cells

    National Research Council Canada - National Science Library

    Haile, Sossina M

    2005-01-01

    ...) without pressurization. In this configuration, the thin-film fuel cell is supported on a porous stainless steel gas diffusion layer and the electrocatalyst and electrolyte layers are spray-deposited...

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

    DEFF Research Database (Denmark)

    Thomas, Sobi; Bates, Alex; Park, Sam

    2016-01-01

    without pins and another with pins. A five-cell stack was fabricated in the lab based on the new design. Performance and flow distribution studies revealed better performance, uniform flow distribution, and a reduced temperature gradient across the stack; improving overall system efficiency.......A minimum balance of plant (BOP) is desired for an open-cathode high temperature polymer electrolyte membrane (HTPEM) fuel cell to ensure low parasitic losses and a compact design. The advantage of an open-cathode system is the elimination of the coolant plate and incorporation of a blower...... for oxidant and coolant supply, which reduces the overall size of the stack, power losses, and results in a lower system volume. In the present study, we present unique designs for an open-cathode system which offers uniform temperature distribution with a minimum temperature gradient and a uniform flow...

  1. Measurement and modelling of local phenomena in polymer electrolyte fuel cells; Messung und Modellierung lokaler Phaenomene in Polymer-Elektrolyt-Brennstoffzellen

    Energy Technology Data Exchange (ETDEWEB)

    Eckl, R.

    2007-05-15

    Within the scope of this thesis, a new method for in situ current distribution measurement based on printed circuit board technology is developed and applied to polymer electrolyte fuel cells. Using the finite element method, the accuracy of this new approach is compared to conventional techniques and an estimate of the maximum uncertainty of measurement due to lateral currents is given. The effects of variable operating parameters on local electrochemical performance are studied by stationary and dynamic testing of laboratory cells with 100 cm{sup 2} active area. Based on experimental results, load conditions on the anode side are modelled and characteristic water management issues are analysed with the aid of computational fluid dynamics (CFD) simulations. (orig.)

  2. Solid Oxide Fuel Cell

    DEFF Research Database (Denmark)

    2010-01-01

    The solid oxide fuel cell comprising a metallic support material, an active anode layer consisting of a good hydrocarbon cracking catalyst, an electrolyte layer, an active cathode layer, and a transition layer consisting of preferably a mixture of LSM and a ferrite to the cathode current collector...

  3. Analysis of alkaline exchange membrane fuel cells performance at different operating conditions using DC and AC methods

    Science.gov (United States)

    Reshetenko, Tatyana; Odgaard, Madeleine; Schlueter, Debbie; Serov, Alexey

    2018-01-01

    Membrane electrode assemblies (MEAs) for anion exchange membrane fuel cells (AEMFCs) were manufactured from commercial materials: Pt/C catalyst, A201 AEM and AS4 ionomer by using an industrial mass-production digital printing method. The MEA designs selected are close to those recommended by US Department of Energy, including low loading of platinum on the cathode side (0.2 mg cm-2). Polarization curves and electrochemical impedance spectroscopy (EIS) were applied for MEA evaluation in fuel cell conditions with variation of gas humidification and oxygen partial pressure (air vs oxygen). The typical impedance curves recorded at H2/O2 gas configuration consist of high- and medium-frequency arcs responsible for hydrogen oxidation and oxygen reduction, respectively. Operation with air as a cathode feed gas resulted in a decrease in AEMFC performance due to possible CO2 poisoning and mass transfer losses. At the same time, EIS demonstrated formation of a low frequency loop due to diffusion limitations. Despite the low loading of platinum on the cathode (0.2 mg cm-2), a peak power density of ∼330 mW cm-2 was achieved (at 50/50% of RH on anode and cathode), which is substantially higher performance than for AEMFC MEAs tested at similar conditions.

  4. Effect of surface treatment on the interfacial contact resistance and corrosion resistance of Fe–Ni–Cr alloy as a bipolar plate for polymer electrolyte membrane fuel cells

    International Nuclear Information System (INIS)

    Yang, Meijun; Zhang, Dongming

    2014-01-01

    The bipolar plate is an important component of the PEMFC (polymer electrolyte membrane fuel cell) because it supplies the pathway of electron flow between each unit cell. Fe–Ni–Cr alloy is considered as a good candidate material for bipolar plate, but it is limited to use as a bipolar plate due to its high ICR (interfacial contact resistance) and corrosion problem. In order to explore a cost-effective method on surface modification, various chemical and electrochemical treatments are performed on Fe–Ni–Cr alloy to acquire the effect of the surface modification on the ICR and corrosion behavior. The ICR and corrosion resistance of Fe–Ni–Cr alloy can be effectively controlled by the chemical treatment of immersion in the mixed acid solution with 10 vol% HNO 3 , 2 vol% HCl and 1 vol% HF for 10 min at 65 °C and then was placed in 30 vol% HNO 3 solution for 5 min. The chemical treatment is more effective on reducing ICR and improving corrosion resistance than that of electrochemical methods (be carried out in the 2 mol/L H 2 SO 4 solution with the electrical potential from −0.4 V to 0.6 V) for Fe–Ni–Cr alloy as a bipolar plate for polymer electrolyte membrane fuel cells. - Highlights: • The procedure of the surface treatments on Fe–Ni–Cr alloy as bipolar plate was described in detail. • Effects of various surface treatments on the interfacial contact resistivity and corrosion behavior were discussed. • The mechanism of the surface modification was particularly analyzed

  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

    humidification conditions. It was found that the specific surface area of the electrolyte in the catalyst layers close to the membrane is of critical importance for the overall water balance. Applying a high specific electrolyte surface area close to the membrane (a water-uptake layer) can prevent drying out...

  6. Modeling coupled transport and electrochemical reaction phenomena in polymer electrolyte fuel cell electrode by Lattice Boltzmann method

    Science.gov (United States)

    Tarokh, Atefeh; Tarokh, Ali; Hejazi, Hossein; Karan, Kunal

    2015-11-01

    Fuel cells convert chemical energy of a fuel directly into electricity. The overall process is a result of coupled reaction-transport processes. The electrochemical reactions occur in porous composite catalysts layers with intermingled material phases, often made up of nano-sized particles and nano/micrometers pores. In a polymer electrolye fuel cell (PEFC) catalyst layer, the focus of this work, transport of electrons through carbon, transport of protons through ion-conducting polymer (ionomer), diffusion of gases through pores must be considered. The three different reacting species, viz. protons, electrons and reactive molecule (H2 or O2) must co-exist at the reactive interface formed by Pt catalyst surface covered by an ionomer film. We use Lattice Boltzmann Method to capture the interactions between chemistry, transport and porous medium geometries in a PEFC catalyst layer. We report the simulation results for a model but novel catalyst architecture made of a continuous carbon phase with organized pore structure. The Pt catalyst is dispersed on the internal surface of the carbon. This Pt-catalyst decorated surface is covered by a thin ionomer film. In particular, we are interested in explicitly capturing the complexity of the pore geometry and Knudsen diffusion effects.

  7. Electrolytes for magnesium electrochemical cells

    Science.gov (United States)

    Burrell, Anthony K.; Sa, Niya; Proffit, Danielle Lee; Lipson, Albert; Liao, Chen; Vaughey, John T.; Ingram, Brian J.

    2017-07-04

    An electrochemical cell includes a high voltage cathode configured to operate at 1.5 volts or greater; an anode including Mg.sup.0; and an electrolyte including an ether solvent and a magnesium salt; wherein: a concentration of the magnesium salt in the ether is 1 M or greater.

  8. Gas-Phase Mass-Transfer Resistances at Polymeric Electrolyte Membrane Fuel Cells Electrodes: Theoretical Analysis on the Effectiveness of Interdigitated and Serpentine Flow Arrangements

    Directory of Open Access Journals (Sweden)

    Elisabetta Arato

    2016-03-01

    Full Text Available Mass transfer phenomena in polymeric electrolyte membrane fuel cells (PEMFC electrodes has already been analyzed in terms of the interactions between diffusive and forced flows. It was demonstrated that the whole phenomenon could be summarized by expressing the Sherwood number as a function of the Peclet number. The dependence of Sherwood number on Peclet one Sh(Pe function, which was initially deduced by determining three different flow regimes, has now been given a more accurate description. A comparison between the approximate and the accurate results for a reference condition of diluted reactant and limit current has shown that the former are useful for rapid, preliminary calculations. However, a more precise and reliable estimation of the Sherwood number is worth attention, as it provides a detailed description of the electrochemical kinetics and allows a reliable comparison of the various geometrical arrangements used for the distribution of the reactants.

  9. The platinum catalyst layer in polymer-electrolyte fuel cells[Dissertation 17127]; Die Platinkatalysatorschicht in Polymerelektrolyt-Brennstoffzellen. Beitraege zum Verstaendnis und zur Optimierung

    Energy Technology Data Exchange (ETDEWEB)

    Reiner, A.

    2007-07-01

    This illustrated, comprehensive dissertation by Dr. Andreas Reiner presents an in-depth analysis of polymer electrolyte fuel cells (PEFC) and in particular, their platinum catalyst layer. First of all, the thermodynamics and kinetics involved are reviewed, along with components, their efficiencies and the catalyst layer. The methods used, including scanning electron microscope, x-ray and Rutherford spectroscopy are discussed. The structure and composition of co-sputtered catalyst layers and their production are described. Electro-chemical activation and the electro-chemical properties of the layers are discussed. The second part of the dissertation deals with the principle of hydrogen under-potential deposition. This method provides information about the electrochemically active platinum surface fraction. The results of investigations made are presented and discussed.

  10. Pore network modeling to explore the effects of compression on multiphase transport in polymer electrolyte membrane fuel cell gas diffusion layers

    Science.gov (United States)

    Fazeli, Mohammadreza; Hinebaugh, James; Fishman, Zachary; Tötzke, Christian; Lehnert, Werner; Manke, Ingo; Bazylak, Aimy

    2016-12-01

    Understanding how compression affects the distribution of liquid water and gaseous oxygen in the polymer electrolyte membrane fuel cell gas diffusion layer (GDL) is vital for informing the design of improved porous materials for effective water management strategies. Pore networks extracted from synchrotron-based micro-computed tomography images of compressed GDLs were employed to simulate liquid water transport in GDL materials over a range of compression pressures. The oxygen transport resistance was predicted for each sample under dry and partially saturated conditions. A favorable GDL compression value for a preferred liquid water distribution and oxygen diffusion was found for Toray TGP-H-090 (10%), yet an optimum compression value was not recognized for SGL Sigracet 25BC. SGL Sigracet 25BC exhibited lower transport resistance values compared to Toray TGP-H-090, and this is attributed to the additional diffusion pathways provided by the microporous layer (MPL), an effect that is particularly significant under partially saturated conditions.

  11. CERDEC Fuel Cell Team: Military Transitions for Soldier Fuel Cells

    Science.gov (United States)

    2008-10-27

    Continued Ardica: 20W Wearable PEMFC operating on Chemical Hydrides Spectrum Brands w/ Rayovac: Hydrogen Generators and Alkaline Fuel Cells for AA...running on JP-8 / diesel fuel & 250W RMFC Aspen : 5kWe integrated desulfurizer and JP-8 / diesel fuel processor Altex: 2-kWe integrated desulfurizer...and JP-8 / diesel fuel processor Precision Combustion : 5-kWt integrated desulfurizer and JP-8 and diesel fuel processor Customers Partners Army

  12. Investigation of the effect of a hydrophilic layer in the gas diffusion layer of a polymer electrolyte membrane fuel cell on the cell performance and cold start behaviour

    International Nuclear Information System (INIS)

    Hirakata, Satoki; Hara, Masanori; Kakinuma, Katsuyosi; Uchida, Makoto; Tryk, Donald A.; Uchida, Hiroyuki; Watanabe, Masahiro

    2014-01-01

    Highlights: • Gas diffusion layer (GDL) characterization was carried out by Raman spectroscopy. • A fuel cell using a GDL with a hydrophilic layer showed superior performance. • This cell also showed favorable cold start performance from -10 °C. • The hydrophilic layer improves water retention under low humidity conditions. • The hydrophilic layer enhances water removal for high humidity and cold startup. - Abstract: The effect on PEFC performance of a gas diffusion layer (GDL) with a hydrophilic layer (HL) between the microporous layer (MPL) and the carbon paper (CP) was investigated at high and low humidity at normal operating temperatures and at subfreezing temperatures. Scanning electron microscopic examination and micro-Raman spectroscopic examination were carried out on the three-layer structure (MPL, HL and CP). In addition, high magnification SEM images of the samples showed that the HL had smaller pores than the MPL of the HL-GDL. Thus, we consider that the capillary pressure in the pores of the HL was higher than that in the MPL of the HL-GDL, which suggests that the HL can absorb more water. The performances of cells using the GDL with or without a HL were compared. The cell using a GDL with a HL showed a higher performance than a cell with a conventional GDL in the high current density region at both high and low humidity. At high humidity, the HL can absorb generated water, improving water removal from the catalyst layer (CL) to the GDL, and inhibiting the stoppage of gas diffusion by condensed water in the CL. At low humidity, the HL enhanced the water retention in the MEA, inhibiting the decrease of proton conductivity of the electrolyte by dehydration. A cell using a GDL with a HL also showed superior performance during cold startup from -10 °C, due to water removal by the HL, inhibiting the blockage of gas diffusion by condensed or frozen water in the CL. These results indicate that an HL placed between the MPL and the carbon paper of

  13. Non-contact electric potential measurements of electrode components in an operating polymer electrolyte fuel cell by near ambient pressure XPS.

    Science.gov (United States)

    Yu, Liwei; Takagi, Yasumasa; Nakamura, Takahiro; Sekizawa, Oki; Sakata, Tomohiro; Uruga, Tomoya; Tada, Mizuki; Iwasawa, Yasuhiro; Samjeské, Gabor; Yokoyama, Toshihiko

    2017-11-22

    Photoelectron spectroscopy has the advantage of providing electric potentials by non-contact measurements based on the kinetic energy shift in component potential. We performed operando hard X-ray photoelectron spectroscopy (HAXPES) measurements with an 8 keV excitation source to measure the shift in electron kinetic energies as a function of the voltages of all the components at the anode and cathode electrodes of a polymer electrolyte fuel cell (PEFC). At the cathode electrode, when we increase the voltage between the cathode and anode from 0.2 to 1.2 V, the O 1s and F 1s peaks shift to a lower binding energy and the magnitude of the energy shift is equal to the voltage. The Pt 3d and C 1s peaks do not shift with the voltage since platinum nanoparticles and carbon supports at the cathode electrode have ground contact. In contrast to the cathode electrode, the peak shifts of all the components at the anode electrode show the same amount of shift as the voltages. It is clear that the change in the potential difference occurs only in an electrical double layer at the interface between the cathode electrode (Pt/C) and the electrolyte (Nafion and water), and that the anode electrode is in equilibrium as a pseudo-hydrogen electrode. Moreover, the electric potential variation of the cathode electrode in a PEFC under a power generation condition was also directly detected by operando HAXPES.

  14. RE/H2 Production Micro-System Based on Standard Alkaline Electrolytic Technology

    International Nuclear Information System (INIS)

    Moschetto, A.; Tina, G.M.; Ferraro, M.; Briguglio, N.; Antonucci, V.

    2006-01-01

    This paper presents the first task of a more comprehensive research project focused on the development of micro-scale (1-20 kW) Renewable Hydrogen (RE/H 2 ) production systems oriented to carry on a wide campaign of educational and demonstration projects. The paper proposes to rely on low-cost and rugged 'standard' alkaline electrolytic technology, well suited for decentralized hydrogen production, but requiring a certain R and D effort to get technical competitiveness. An electrolyser test facility has been designed and carried out. Then performance assessment of a commercial electrolyser and its sub-systems has been accomplished. First experimental results stated that the unit under test gets an average production efficiency of 51%, versus a stack (cell) efficiency of about 62%, while the aged AC/DC power converter, to be removed or replaced to adapt the unit to DC link with renewables, requires more than 16% of the incoming power. (authors)

  15. Composite Solid Electrolyte For Lithium Cells

    Science.gov (United States)

    Peled, Emmanuel; Nagasubramanian, Ganesan; Halpert, Gerald; Attia, Alan I.

    1994-01-01

    Composite solid electrolyte material consists of very small particles, each coated with thin layer of Lil, bonded together with polymer electrolyte or other organic binder. Material offers significant advantages over other solid electrolytes in lithium cells and batteries. Features include high ionic conductivity and strength. Composite solid electrolyte expected to exhibit flexibility of polymeric electrolytes. Polymer in composite solid electrolyte serves two purposes: used as binder alone, conduction taking place only in AI2O3 particles coated with solid Lil; or used as both binder and polymeric electrolyte, providing ionic conductivity between solid particles that it binds together.

  16. An experimental study on the cathode humidification and evaporative cooling of polymer electrolyte membrane fuel cells using direct water injection method at high current densities

    International Nuclear Information System (INIS)

    Hwang, Seong Hoon; Kim, Min Soo

    2016-01-01

    Highlights: • Proposal of a cathode humidification and evaporative cooling system for PEM fuel cells. • An external-mixing air-assist atomizer is used to produce a very fine water spray. • The system is effective in both cathode humidification and stack cooling. • Increased water flow rate improves stack performance and evaporative cooling capacity. • At a given water flow rate, lower stack temperatures cause greater humidification effect. - Abstract: Humidification and cooling are critical issues in enhancing the efficiency and durability of polymer electrolyte membrane fuel cells (PEMFCs). However, existing humidifiers and cooling systems have the disadvantage that they must be quite large to achieve adequate PEMFC performance. In this study, to eliminate the need for a bulky humidifier and to lighten the cooling load of PEMFCs, a cathode humidification and evaporative cooling system using an external-mixing air-assist atomizer was developed and its performance was investigated. The atomization performance of the nozzle was analyzed experimentally under various operating conditions with minimal changes in the system design. Experiments with a five-cell PEMFC stack with an active area of 250 cm 2 were carried out to analyze the effects of various parameters (such as the operating temperature, current density, and water injection flow rate) on the evaporation of injected water for humidification and cooling performances. The experimental results demonstrate that the direct water injection method proposed in this study is quite effective in cathode humidification and stack cooling in PEM fuel cells at high current densities. The stack performance was improved by humidification effect and the coolant temperature at the stack outlet decreased by evaporative cooling effect.

  17. Enhanced Performance of Membraneless Sodium Percarbonate Fuel Cells

    Directory of Open Access Journals (Sweden)

    M. Gowdhamamoorthi

    2013-01-01

    Full Text Available This paper presents the continuous flow operation of membraneless sodium percarbonate fuel cell (MLSPCFC using acid/alkaline bipolar electrolyte. In the acid/alkaline bipolar electrolyte, percarbonate works both as an oxidant as well as reductant. Sodium percarbonate affords hydrogen peroxide in aqueous medium. The cell converts the energy released by H2O2 decomposition with H+ and OH− ions into electricity and produces water and oxygen. At room temperature, the laminar flow based microfluidic membraneless fuel cell can reach a maximum power density of 28 mW/cm2 with the molar ratio of [Percarbonate]/[NaOH] = 1 as fuel and [Percarbonate]/[H2SO4] = 2 as oxidant. The paper reports for the first time the use of sodium percarbonate as the oxidant and reductant. The developed fuel cell emits no CO2 and features no proton exchange membrane, inexpensive catalysts, and simple planar structure, which enables high design flexibility and easy integration of the microscale fuel cell into actual microfluidic systems and portable power applications.

  18. Effect of Light/Dark Regimens on Hydrogen Production by Tetraselmis subcordiformis Coupled with an Alkaline Fuel Cell System.

    Science.gov (United States)

    Guo, Zhen; Li, Ying; Guo, Haiyan

    2017-12-01

    To improve the photoproduction of hydrogen (H 2 ) by a green algae-based system, the effect of light/dark regimens on H 2 photoproduction regulated by carbonyl cyanide m-chlorophenylhydrazone (CCCP) was investigated. A fuel cell was integrated into a photobioreactor to allow online monitoring of the H 2 evolution rate and decrease potential H 2 feedback inhibition by consuming the generated H 2 in situ. During the first 15 h of H 2 evolution, the system was subjected to dark treatment after initial light illumination (L/D = 6/9 h, 9/6 h, and 12/3 h). After the dark period, all systems were again exposed to light illumination until H 2 evolution stopped. Two peaks were observed in the H 2 evolution rate under all three light/dark regimens. Additionally, a high H 2 yield of 126 ± 10 mL L -1 was achieved using a light/dark regimen of L 9 h/D 6 h/L until H 2 production ceased, which was 1.6 times higher than that obtained under continuous illumination. H 2 production was accompanied by some physiological and morphological changes in the cells. The results indicated that light/dark regimens improved the duration and yield of H 2 photoproduction by the CCCP-regulated process of Tetraselmis subcordiformis.

  19. 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.

  20. Zirconium phosphate as the proton conducting material in direct hydrocarbon polymer electrolyte membrane fuel cells operating above the boiling point of water

    Energy Technology Data Exchange (ETDEWEB)

    Al-Othman, Amani [Chemical and Biological Engineering, University of Ottawa, 161 Louis Pasteur, Ottawa, ON K1N 6N5 (Canada); Catalysis Centre for Research and Innovation, University of Ottawa, 161 Louis Pasteur, Ottawa, ON K1N 6N5 (Canada); Tremblay, Andre Y. [Chemical and Biological Engineering, University of Ottawa, 161 Louis Pasteur, Ottawa, ON K1N 6N5 (Canada); Pell, Wendy; Letaief, Sadok [Catalysis Centre for Research and Innovation, University of Ottawa, 161 Louis Pasteur, Ottawa, ON K1N 6N5 (Canada); Burchell, Tara J. [Department of Physics, University of Ottawa, 161 Louis Pasteur, Ottawa, ON K1N 6N5 (Canada); Peppley, Brant A. [Chemical Engineering, Queens University, Dupuis Hall, Kingston, ON K7L 3N6 (Canada); Ternan, Marten [EnPross Inc., 147 Banning Road, Ottawa, ON K2L 1C5 (Canada)

    2010-05-01

    Zirconium phosphate (ZrP) was investigated as a possible proton conductor material in direct hydrocarbon polymer electrolyte membrane (PEM) fuel cells that operate at greater temperatures than conventional PEM fuel cells. Amorphous zirconium phosphate was synthesized in this work by precipitation at room temperature via reaction of ZrOCl{sub 2} with H{sub 3}PO{sub 4} aqueous solutions. The conductivity of the synthesized ZrP materials were 7.04 x 10{sup -5} S cm{sup -1} for ZrP oven dried in laboratory air at 70 C and 3.57 x 10{sup -4} S cm{sup -1} for ZrP powder dried first at 70 C in laboratory air and then processed at 200 C with continuous H{sub 2}O injection at an H{sub 2}O/N{sub 2} molar ratio of 6. This work showed that by maintaining appropriate water content in the vapour phase at processing conditions, it was possible to alter the composition of zirconium phosphate to a sufficiently hydrated state, and thereby avoid the normal decrease in conductivity with increasing temperature. (author)

  1. Influence of thermal post-curing on the degradation of a cross-linked polybenzimidazole-based membrane for high temperature polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Ossiander, T.; Perchthaler, M.; Heinzl, C.; Scheu, C.

    2014-12-01

    The lifetime stability of membranes is one of the main requirements regarding reliability of high temperature polymer electrolyte membrane fuel cells. The present work has improved durability under cycled operation by thermal post-curing of cross-linked polybenzimidazole (PBI)-based membranes. The membranes were dried over 1, 2 and 3 h at 250 °C under air. Ex-situ experiments proved an increase in stability by post-curing. The liquid uptake and swelling in phosphoric acid increased with longer curing periods. The effect of thermal treatments on cycle stability, lifetime and begin-of-life performance of the membrane electrode assemblies (MEAs) was investigated. Longer post-curing periods of the membranes had no influence on the MEAs' begin-of-life performance and constant current behavior over 2300 h. However, the 3 h post-cured MEAs showed enhanced cycle stability. Post-mortem analysis was carried out to identify the occurring degradation mechanisms. While a significant loss of phosphoric acid and a reduction of electrochemical surface activity on the cathode were observed for both post-cured MEAs, the 3 h dried membrane sample had a significantly higher resistance against pinhole formation during the long term test. Altogether, this work presents thermal post-curing as a promising method for the reduction of degradation determining effects in fuel cell membranes.

  2. Carbon supported Pd-Ni and Pd-Ru-Ni nanocatalysts for the alkaline direct ethanol fuel cell (DEFC)

    CSIR Research Space (South Africa)

    Mathe, MK

    2011-08-01

    Full Text Available Carbon supported Pd-Ni and Pd-Ru-Ni nanocatalysts were prepared by the chemical reduction method, using sodium borohydride and ethylene glycol mixture as the reducing agent. The catalytic activity towards ethanol electro-oxidation in alkaline medium...

  3. Fuel Cells

    DEFF Research Database (Denmark)

    Smith, Anders; Pedersen, Allan Schrøder

    2014-01-01

    Fuel cells have been the subject of intense research and development efforts for the past decades. Even so, the technology has not had its commercial breakthrough yet. This entry gives an overview of the technological challenges and status of fuel cells and discusses the most promising applications...

  4. Task 1: Modeling Study of CO Effects on Polymer Electrolyte Fuel Cell Anodes Task 2: Study of Ac Impedance as Membrane/Electrode Manufacturing Diagnostic Tool

    Energy Technology Data Exchange (ETDEWEB)

    Thomas E. Springer

    1998-01-30

    Carbon monoxide poisoning of polymer electrolyte fuel cell anodes is a key problem to be overcome when operating a polymer electrolyte fuel cell (PEFC) on reformed fuels. CO adsorbs preferentially on the precious metal surface leading to substantial performance losses. Some recent work has explored this problem, primarily using various Pt alloys in attempts to lower the degree of surface deactivation. In their studies of hydrogen oxidation on Pt and Pt alloy (Pt/Sn, Pt/Ru) rotating disk electrodes exposed to H{sub 2}/CO mixtures, Gasteiger et al. showed that a small hydrogen oxidation current is observed well before the onset of major CO oxidative stripping (ca. 0.4 V) on Pt/Ru. However, these workers concluded that such current observed at low anode overpotentials was too low to be of practical value. Nonetheless, MST-11 researchers and others have found experimentally that it is possible to run a PEFC, e.g., with a Pt/Ru anode, in the presence of CO levels in the range 10--100 ppm with little voltage loss. Such experimental results suggest that, in fact, PEFC operation at significant current densities under low anode overpotentials is possible in the presence of such levels of CO, even before resorting to air bleeding into the anode feed stream. The latter approach has been shown to be effective in elimination of Pt anode catalyst poisoning effects at CO levels of 20--50 ppm for cells operating at 80 C with low Pt catalyst loading. The effect of oxygen bleeding is basically to lower P{sub CO} down to extremely low levels in the anode plenum thanks to the catalytic (chemical) oxidation of CO by dioxygen at the anode catalyst. In this modeling work the authors do not include specific description of oxygen bleeding effects and concentrate on the behavior of the anode with feed streams of H{sub 2} or reformate containing low levels of CO. The anode loss is treated in this work as a hydrogen and carbon monoxide electrode kinetics problem, but includes the effects of

  5. Evaluation of electricity generation from ultrasonic and heat/alkaline pretreatment of different sludge types using microbial fuel cells.

    Science.gov (United States)

    Oh, Sang-Eun; Yoon, Joung Yee; Gurung, Anup; Kim, Dong-Jin

    2014-08-01

    This study investigated the effects of different sludge pretreatment methods (ultrasonic vs. combined heat/alkali) with varied sources of municipal sewage sludge (primary sludge (PS), secondary excess sludge (ES), anaerobic digestion sludge (ADS)) on electricity generation in microbial fuel cells (MFCs). Introduction of ultrasonically pretreated sludge (PS, ES, ADS) to MFCs generated maximum power densities of 13.59, 9.78 and 12.67mW/m(2) and soluble COD (SCOD) removal efficiencies of 87%, 90% and 57%, respectively. The sludge pretreated by combined heat/alkali (0.04N NaOH at 120°C for 1h) produced maximum power densities of 10.03, 5.21 and 12.53mW/m(2) and SCOD removal efficiencies of 83%, 75% and 74% with PS, ES and ADS samples, respectively. Higher SCOD by sludge pretreatment enhanced performance of the MFCs and the electricity generation was linearly proportional to the SCOD removal, especially for ES. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Structural and morphological changes in supramolecular-structured polymer electrolyte membrane fuel cell on addition of phosphoric acid

    Science.gov (United States)

    Hendrana, S.; Pryliana, R. F.; Natanael, C. L.; Rahayu, I.

    2018-03-01

    Phosphoric acid is one agents used in membrane fuel cell to modify ionic conductivity. Therefore, its distribution in membrane is a key parameter to gain expected conductivity. Efforts have been made to distribute phosphoric acid in a supramolecular-structured membrane prepared with a matrix. To achieve even distribution across bulk of the membrane, the inclusion of the polyacid is carried out under pressurized chamber. Image of scanning electron microscopy (SEM) shows better phosphoric acid distribution for one prepared in pressurized state. It also leads in better performing in ionic conductivity. Moreover, data from differential scanning calorimetry (DSC) indicate that the addition of phosphoric acid is prominent in the change of membrane structure, while morphological changes are captured in SEM images.

  7. Synthesis and properties of poly(aryl sulfone benzimidazole) and its copolymers for high temperature membrane electrolytes for fuel cells

    DEFF Research Database (Denmark)

    Yang, Jingshuai; Li, Qingfeng; Cleemann, Lars Nilausen

    2012-01-01

    Poly(aryl sulfone benzimidazole) (SO2PBI) and its copolymers with poly[2,2′-p-(phenylene)-5,5′-bibenzimidazole] (pPBI), termed as Co-SO2PBI, were synthesized with varied feeding ratios of 4,4′-sulfonyldibenzoic acid (SDBA) to terephthalic acid (TPA). Incorporation of the stiff para......, the membrane swelling was reduced and the mechanical strength was improved, as compared with their meta structured analogues. At an acid doping level of 11 mol H3PO4 per average molar repeat unit, the Co-20%SO2PBI membrane exhibited a tensile strength of 16 MPa at room temperature and an H2-air fuel cell peak...

  8. Fuel cell research: Towards efficient energy

    CSIR Research Space (South Africa)

    Rohwer, MB

    2008-11-01

    Full Text Available fuel cells by optimising the loading of catalyst (being expensive noble metals) and ionomer; 2) Improving conventional acidic direct alcohol fuel cells by developing more efficient catalysts and by investigating other fuels than methanol; 3...) Investigating anionic membranes for use in alkaline direct alcohol fuel cells, as cheaper and more efficient alternatives to conventional acidic direct alcohol fuel cells. The aim of the authors’ research activities is to develop fuel cell...

  9. Superprotonic KH(PO3H)-SiO2 composite electrolyte for intermediate temperature fuel cells

    NARCIS (Netherlands)

    Bandarenka, A.; Bondarenko, Alexander S.; Zhou, W.; Bouwmeester, Henricus J.M.

    2009-01-01

    Novel thin film composite electrolyte membranes, prepared by dispersion of nano-sized SiO2 particles in the solid acid compound KH(PO3H), can be operated under both oxidizing and reducing conditions. Long-term stable proton conductivity is observed at not, vert, similar140 °C, i.e., slightly above

  10. Fuel cell cassette with compliant seal

    Science.gov (United States)

    Karl, Haltiner, Jr. J.; Anthony, Derose J.; Klotzbach, Darasack C.; Schneider, Jonathan R.

    2017-11-07

    A fuel cell cassette for forming a fuel cell stack along a fuel cell axis includes a cell retainer, a plate positioned axially to the cell retainer and defining a space axially with the cell retainer, and a fuel cell having an anode layer and a cathode layer separated by an electrolyte layer. The outer perimeter of the fuel cell is positioned in the space between the plate and the cell retainer, thereby retaining the fuel cell and defining a cavity between the cell retainer, the fuel cell, and the plate. The fuel cell cassette also includes a seal disposed within the cavity for sealing the edge of the fuel cell. The seal is compliant at operational temperatures of the fuel cell, thereby allowing lateral expansion and contraction of the fuel cell within the cavity while maintaining sealing at the edge of the fuel cell.

  11. Determination of hydroxide and carbonate contents of alkaline electrolytes containing zinc

    Science.gov (United States)

    Otterson, D. A.

    1975-01-01

    A method to prevent zinc interference with the titration of OH- and CO3-2 ions in alkaline electrolytes with standard acid is presented. The Ba-EDTA complex was tested and shown to prevent zinc interference with acid-base titrations without introducing other types of interference. Theoretical considerations indicate that this method can be used to prevent interference by other metals.

  12. Validity of two-phase polymer electrolyte membrane fuel cell models with respect to the gas diffusion layer

    Science.gov (United States)

    Ziegler, C.; Gerteisen, D.

    A dynamic two-phase model of a proton exchange membrane fuel cell with respect to the gas diffusion layer (GDL) is presented and compared with chronoamperometric experiments. Very good agreement between experiment and simulation is achieved for potential step voltammetry (PSV) and sine wave testing (SWT). Homogenized two-phase models can be categorized in unsaturated flow theory (UFT) and multiphase mixture (M 2) models. Both model approaches use the continuum hypothesis as fundamental assumption. Cyclic voltammetry experiments show that there is a deterministic and a stochastic liquid transport mode depending on the fraction of hydrophilic pores of the GDL. ESEM imaging is used to investigate the morphology of the liquid water accumulation in the pores of two different media (unteflonated Toray-TGP-H-090 and hydrophobic Freudenberg H2315 I3). The morphology of the liquid water accumulation are related with the cell behavior. The results show that UFT and M 2 two-phase models are a valid approach for diffusion media with large fraction of hydrophilic pores such as unteflonated Toray-TGP-H paper. However, the use of the homgenized UFT and M 2 models appears to be invalid for GDLs with large fraction of hydrophobic pores that corresponds to a high average contact angle of the GDL.

  13. Alternative Sources of Energy - An Introduction to Fuel Cells

    Science.gov (United States)

    Merewether, E.A.

    2003-01-01

    Fuel cells are important future sources of electrical power and could contribute to a reduction in the amount of petroleum imported by the United States. They are electrochemical devices similar to a battery and consist of a container, an anode, a cathode, catalysts, an intervening electrolyte, and an attached electrical circuit. In most fuel cell systems, hydrogen is supplied to the anode and oxygen to the cathode which results in the production of electricity, water, and heat. Fuel cells are comparatively efficient and reliable, have no moving parts, operate without combustion, and are modular and scale-able. Their size and shape are flexible and adaptable. In operation, they are nearly silent, are relatively safe, and generally do not pollute the environment. During recent years, scientists and engineers have developed and refined technologies relevant to a variety of fuel cells. Types of fuel cells are commonly identified by the composition of their electrolyte, which could be either phosphoric acid, an alkaline solution, a molten carbonate, a solid metal oxide, or a solid polymer membrane. The electrolyte in stationary power plants could be phosphoric acid, molten carbonates, or solid metal oxides. For vehicles and smaller devices, the electrolyte could be an alkaline solution or a solid polymer membrane. For most fuel cell systems, the fuel is hydrogen, which can be extracted by several procedures from many hydrogen-bearing substances, including alcohols, natural gas (mainly methane), gasoline, and water. There are important and perhaps unresolved technical problems associated with using fuel cells to power vehicles. The catalysts required in several systems are expensive metals of the platinum group. Moreover, fuel cells can freeze and not work in cold weather and can be damaged by impacts. Storage tanks for the fuels, particularly hydrogen, must be safe, inexpensive, of a reasonable size, and contain a supply sufficient for a trip of several hundred miles

  14. Poly (vinyl alcohol) hydrogel membrane as electrolyte for direct ...

    Indian Academy of Sciences (India)

    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 ...

  15. Poly (vinyl alcohol) hydrogel membrane as electrolyte for direct ...

    Indian Academy of Sciences (India)

    Administrator

    Abstract. 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 gold- plated stainless steel mesh as cathode in conjunction with aqueous alkaline solution of sodium boro- hydride as fuel and ...

  16. Fuel cells:

    DEFF Research Database (Denmark)

    Sørensen, Bent

    2013-01-01

    A brief overview of the progress in fuel cell applications and basic technology development is presented, as a backdrop for discussing readiness for penetration into the marketplace as a solution to problems of depletion, safety, climate or environmental impact from currently used fossil...... and nuclear fuel-based energy technologies....

  17. Preparation of poly(ether ether ketone)-based polymer electrolytes for fuel cell membranes using grafting technique

    International Nuclear Information System (INIS)

    Hasegawa, Shin; Suzuki, Yasuyuki; Maekawa, Yasunari

    2008-01-01

    Poly(ether ether ketone) (PEEK)-based polymer electrolyte membranes (PEMs) was successfully prepared by radiation grafting of a styrene monomer into PEEK films and the consequent selective sulfonation of the grafting chains in the film state. Using milder sulfonation, the sulfonation reactions proceeded at the grafted chains in preference to the phenylene rings of PEEK main chains; as a result, the grafted films could successfully transform to a PEM with conductivity of more than 0.1 S/cm. The ion exchange capacity (IEC) and conductivity of the grafted PEEK electrolyte membranes were controlled to the ranges of 1.2-2.9 mmol/g and 0.03-0.18 S/cm by changing the grafting degree. It should be noted that this is the first example of directly transforming super-engineering plastic films into a PEM using radiation grafting

  18. Nanotechnology convergence and modeling paradigm of sustainable energy system using polymer electrolyte membrane fuel cell as a benchmark example

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Pil Seung; So, Dae Sup; Biegler, Lorenz T.; Jhon, Myung S., E-mail: mj3a@andrew.cmu.edu [Carnegie Mellon University, Department of Chemical Engineering (United States)

    2012-08-15

    Developments in nanotechnology have led to innovative progress and converging technologies in engineering and science. These demand novel methodologies that enable efficient communications from the nanoscale all the way to decision-making criteria for actual production systems. In this paper, we discuss the convergence of nanotechnology and novel multi-scale modeling paradigms by using the fuel cell system as a benchmark example. This approach includes complex multi-phenomena at different time and length scales along with the introduction of an optimization framework for application-driven nanotechnology research trends. The modeling paradigm introduced here covers the novel holistic integration from atomistic/molecular phenomena to meso/continuum scales. System optimization is also discussed with respect to the reduced order parameters for a coarse-graining procedure in multi-scale model integration as well as system design. The development of a hierarchical multi-scale paradigm consolidates the theoretical analysis and enables large-scale decision-making of process level design, based on first-principles, and therefore promotes the convergence of nanotechnology to sustainable energy technologies.

  19. Nanotechnology convergence and modeling paradigm of sustainable energy system using polymer electrolyte membrane fuel cell as a benchmark example

    Science.gov (United States)

    Chung, Pil Seung; So, Dae Sup; Biegler, Lorenz T.; Jhon, Myung S.

    2012-08-01

    Developments in nanotechnology have led to innovative progress and converging technologies in engineering and science. These demand novel methodologies that enable efficient communications from the nanoscale all the way to decision-making criteria for actual production systems. In this paper, we discuss the convergence of nanotechnology and novel multi-scale modeling paradigms by using the fuel cell system as a benchmark example. This approach includes complex multi-phenomena at different time and length scales along with the introduction of an optimization framework for application-driven nanotechnology research trends. The modeling paradigm introduced here covers the novel holistic integration from atomistic/molecular phenomena to meso/continuum scales. System optimization is also discussed with respect to the reduced order parameters for a coarse-graining procedure in multi-scale model integration as well as system design. The development of a hierarchical multi-scale paradigm consolidates the theoretical analysis and enables large-scale decision-making of process level design, based on first-principles, and therefore promotes the convergence of nanotechnology to sustainable energy technologies.

  20. Nanotechnology convergence and modeling paradigm of sustainable energy system using polymer electrolyte membrane fuel cell as a benchmark example

    International Nuclear Information System (INIS)

    Chung, Pil Seung; So, Dae Sup; Biegler, Lorenz T.; Jhon, Myung S.

    2012-01-01

    Developments in nanotechnology have led to innovative progress and converging technologies in engineering and science. These demand novel methodologies that enable efficient communications from the nanoscale all the way to decision-making criteria for actual production systems. In this paper, we discuss the convergence of nanotechnology and novel multi-scale modeling paradigms by using the fuel cell system as a benchmark example. This approach includes complex multi-phenomena at different time and length scales along with the introduction of an optimization framework for application-driven nanotechnology research trends. The modeling paradigm introduced here covers the novel holistic integration from atomistic/molecular phenomena to meso/continuum scales. System optimization is also discussed with respect to the reduced order parameters for a coarse-graining procedure in multi-scale model integration as well as system design. The development of a hierarchical multi-scale paradigm consolidates the theoretical analysis and enables large-scale decision-making of process level design, based on first-principles, and therefore promotes the convergence of nanotechnology to sustainable energy technologies.