Novel evaluation method for degradation rate of polymer electrolytes in fuel cells

A simple and new method has been developed to evaluate the degradation rate of polymer electrolytes caused by the cross-leakage of H-2 or O-2 in PEFCs. Mixed gas of H-2 and air with a constant composition was supplied to a sample powder suspended in water, e.g., consisting of Pt supporting carbon black coated with a perfluorosulfonated acid electrolyte. Fluoride ion released from the electrolyte into the water wits quantitatively analyzed as a function of time. The electrolyte was decomposed only when H-2, O-2, and Pt coexisted. The present method enables to compare the durability of different electrolyte polymers directly under the same controlled environment within a short period. (c) 2005 Elsevier B.V. All rights reserved.