Title

Membrane degradation mechanisms in PEMFCs

Authors

Authors

V. O. Mittal; H. R. Kunz;J. M. Fenton

Comments

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Abbreviated Journal Title

J. Electrochem. Soc.

Keywords

OXYGEN REDUCTION; FUEL-CELLS; RESONANCE; ELECTRODE; CATALYST; NAFION; H2O2; H-2; Electrochemistry; Materials Science, Coatings & Films

Abstract

Nafion membrane degradation was studied in a polymer electrolyte membrane fuel cell (PEMFC) under accelerated decay conditions. Fuel cell effluent water was analyzed to determine the fluoride emission rate. Experimental findings show that formation of active oxygen species from H2O2 decomposition or the direct formation of active oxygen species in the oxygen reduction reaction are not the dominating membrane degradation mechanisms in PEMFCs. Instead, membrane degradation occurs because molecular H-2 and O-2 react on the surface of the Pt catalyst to form the membrane-degrading species. The source of H-2 or O-2 is from reactant crossover through the membrane. The reaction mechanism is chemical in nature and depends upon the catalyst surface properties and the relative concentrations of H-2 and O-2 at the catalyst. The membrane degradation rate also depends on the residence time of active oxygen species in the membrane and volume of the membrane. The sulfonic acid groups in the Nafion side chain are key to the mechanism by which radical species attack the polymer. (C) 2007 The Electrochemical Society.

Journal Title

Journal of the Electrochemical Society

Volume

154

Issue/Number

7

Publication Date

1-1-2007

Document Type

Article

Language

English

First Page

B652

Last Page

B656

WOS Identifier

WOS:000246892000024

ISSN

0013-4651

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