Patent ID: 7883807

Claim:
A method for operating a polymer electrolyte fuel cell having a membrane/electrode assembly for polymer electrolyte fuel cells, comprising operating the polymer electrolyte fuel cell; wherein the membrane/electrode assembly for polymer electrolyte fuel cells comprises an anode and a cathode, each comprising a catalyst layer comprising a proton-conductive fluoropolymer (A) and a catalyst, and a polymer electrolyte membrane comprising a proton-conductive fluoropolymer (B), disposed between the anode and the cathode; wherein each of the above proton-conductive fluoropolymer (A) and the above proton-conductive fluoropolymer (B) has an ion exchange capacity of from 1.4 to 1.8 meq/g dry resin, and each of the above proton-conductive fluoropolymer (A) and the above proton-conductive fluoropolymer (B) has a water content of at most 150 mass %; wherein power generation may be initiated in such an environment that the temperature of the membrane/electrode assembly for polymer electrolyte fuel cells may be below 0° C., and wherein the fluoropolymer (A) comprises repeating units having the group (α): wherein Q 1 is a perfluoroalkylene group which, optionally, may comprise an etheric oxygen atom, Q 2 is a single bond or a perfluoroalkylene group which, optionally, may comprise an etheric oxygen atom, R f1 is a perfluoroalkylene group which, optionally, may comprise an etheric oxygen atom, X is an oxygen atom, a nitrogen atom or a carbon atom, “a” is 0 when X is an oxygen atom, 1 when X is a nitrogen atom, or 2 when X is a carbon atom, and Y is a fluorine atom or a monovalent perfluoro organic group.