Polymer-electrolyte fuel cells

Besides, the corresponding reduction process in the cathode is represented as follows  

The PEFC was first developed for the Gemini space vehicle by General Electric, USA. In this fuel cell type, the electrolyte is an ion-exchange membrane, specifically, a fluorinated sulfonic acid polymer or other similar solid polymer. In general, the polymer consists of a polytetrafluoroethylene (Teflon) backbone with a perfluorinated side chain that is terminated with a sulfonic acid group, which is an outstanding proton conductor. Hydration of the membrane yields dissociation and solvation of the proton of the acid group, since the solvated protons are mobile within the polymer. Subsequently, the only liquid necessary for the operation of this fuel cell type is water [7,8], 

Another characteristic of the proton-conducting membrane is that it has low permeability to oxygen and hydrogen in the gas phase so that a high coulombic efficiency exists [7], In addition, in this fuel cell type, the electrodes are normally formed on a thin layer on each side of a protonconducting polymer membrane used as an electrolyte, and platinum catalysts are required for both the anode and the cathode for the proper operation of this fuel cell [9], 

Water running in the membrane is decisive for an efficient performance hence, the fuel cell has to operate under conditions where the byproduct, water, does not evaporate rapidly than it is generated since the membrane must be hydrated for to function properly. Thereafter, the operating temperature is usually less than 120°C. 

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Polymer Electrolyte Fuel Cell. The electrolyte in a PEFC is an ion-exchange (qv) membrane, a fluorinated sulfonic acid polymer, which is a proton conductor (see Membrane technology). The only Hquid present in this fuel cell is the product water thus corrosion problems are minimal. Water management in the membrane is critical for efficient performance. The fuel cell must operate under conditions where the by-product water does not evaporate faster than it is produced because the membrane must be hydrated to maintain acceptable proton conductivity. Because of the limitation on the operating temperature, usually less than 120°C, H2-rich gas having Htde or no (

As can be seen from Eigure 11b, the output voltage of a fuel cell decreases as the electrical load is increased. The theoretical polarization voltage of 1.23 V/cell (at no load) is not actually realized owing to various losses. Typically, soHd polymer electrolyte fuel cells operate at 0.75 V/cell under peak load conditions or at about a 60% efficiency. The efficiency of a fuel cell is a function of such variables as catalyst material, operating temperature, reactant pressure, and current density. At low current densities efficiencies as high as 75% are achievable. 

Polymer electrolyte fuel cells can be obtained from several developers. These fuel cells deliver about 5 kW of power and measure 30 by 30 by 70 cm (12 X 12 X 28 in.). For the large produc tion volume anticipated if the automotive industry were to adopt the PEFC, a system cost of less than 100/kW may be reached eventually. 

Gottesfeld, S., and Zawodzinski, T. A. (1998). Polymer Electrolyte Fuel Cells, Advances m Electrochemical Science and Engineering, ed. R. Alkire et al. NewYork Wiley. 

A membrane ionomer, in particular a polyelectrolyte with an inert backbone such as Nation . They require a plasticizer (typically water) to achieve good conductivity levels and are associated primarily, in their protonconducting form, with solid polymer-electrolyte fuel cells. 

Development of a CO remover employing microchannel reactor for polymer electrolyte fuel cells... 

A miniature methanol steam reformer for polymer electrolyte fuel cell... 

Dodolet JP, Cote R, Faubert G, Denes G, Guay D, Bertrand P (1998) Iron catalysts prepared by high-temperature pyrolysis of tetraphenylporphyrins adsorbed on carbon black for oxygen reduction in polymer electrolyte fuel cells. Electrochim Acta 43 341-353... 

Gubler, L., S. A. Giirsel, and G. G. Scherer, Radiation-grafted membranes for polymer electrolyte fuel cells. Journal Fuel Cells, August 2005. 

Electrocatalysis of Oxygen Reduction in Polymer Electrolyte Fuel Cells A Brief History and a Critical Examination of Present Theory and Diagnostics... 

ELECTROCATALYSIS OF OXYGEN REDUCTION IN POLYMER ELECTROLYTE FUEL CELLS... 

Springer TE, Wilson MS, Gottesfeld S. 1993. Modeling and experimental diagnostics in polymer electrolyte fuel cells. J Electrochem Soc 140 3513-3526. 

Bomp R, Meyers J, KvovarB, Kim YS, Mukundan R, Garland N, Myers D, Wilson M, GarzonF, Wood D, Zelenay P, Mote K, Stroh K, Zawodzinski T, Boncella J, McGrath JE, Inaba M, Miyatake K, Hori M, Ota K, Ogumi Z, Miyata S, Nishikata A, Siroma Z, Uchimoto Y, Yasuda K, Kimijima Ki, Iwashita N. 2007. Scientific aspects of polymer electrolyte fuel cell durability and degradation. Chem Rev 107 3904-3951. 

Igarashi H, Fujino T, Zhu Y, Uchida H, Watanabe M. 2001. CO tolerance of Pt alloy electrocatalysts for polymer electrolyte fuel cells and the detoxification mechanism. Phys Chem Chem Phys 3 306-314. 

Wang XP, Kumar R, Myers DJ. 2006. Effect of voltage on platinum dissolution relevance to polymer electrolyte fuel cells. Electrochem Solid State Lett 9 A225-A227. 

Polymer electrolyte fuel cells (PEFCs) have attracted great interest as a primary power source for electric vehicles or residential co-generation systems. However, both the anode and cathode of PEFCs usually require platinum or its alloys as the catalyst, which have high activity at low operating temperatures (<100 °C). For large-scale commercialization, it is very important to reduce the amount of Pt used in fuel cells for reasons of cost and limited supply. 

Thamizhmani G, Capuano GA. 1994. Improved electrocatal)Tic oxygen reduction performance of platinum ternary alloy-oxide in solid-polymer-electrolyte fuel cells. J Electrochem Soc 141 968-975. 

Watanabe M, Igarashi H, Fujino T. 1999. Design of CO tolerant anode catalysts for polymer electrolyte fuel cell. Electrochemistry 67 1194-1196. 

Lalande G, Faubert G, Cote R, Guay D, Dodelet JP, Weng LT, Bertrand P. 1996. Catalytic activity and stability of heat-treated iron phthalocyanines for the electroreduction of oxygen in polymer electrolyte fuel cells. J Power Sources 61 227-237. 

Arico AS, Creti P, Antonucci PL, Antonucci V. 1998. Comparison of ethanol and methanol oxidation in a liquid-feed solid polymer electrolyte fuel cell at high temperature. Electrochem Sol Lett 1 66-68. 

Behm RJ, Jusys Z. 2006. The potential of model studies for the understanding of catalyst poisoning and temperature effects in polymer electrolyte fuel cell reaction. J Power Sources 154 327-342. 

Diemant T, Hager T, Hosier HE, Rauscher H, Behm RJ. 2003. Hydrogen adsorption and coadsorption with CO on well-defined himetallic PtRu surfaces—A model study on the CO tolerance of himetallic PtRu anode catalysts in low temperature polymer electrolyte fuel cells. Surf Sci 541 137. 

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