Patent ID: 8178257

Claim:
A polymer electrolyte membrane, comprising: a proton conductive fluoropolymer, comprising repeating units having a group of formula (α): wherein Q 1 is a perfluoroalkylene group optionally comprising an etheric oxygen atom, Q 2 is a single bond or a perfluoroalkylene group optionally comprising an etheric oxygen atom, R fl is a perfluoroalkyl group optionally comprising 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 and 2 when X is a carbon atom, and Y is a fluorine atom or a monovalent perfluoroorganic group wherein an electrical conductivity of the polymer electrolyte membrane is at least 0.07 S/cm at a temperature of 80° C. at a relative humidity of 40% and a water content of the polymer electrolyte membrane is less than 150 mass %.