Patent ID: 7208242

Claim:
A polymer electrolyte fuel cell comprising a pair of electrodes consisting of an oxygen electrode and a fuel electrode both having a catalyst layer containing a catalyst and an ion conductive material, and a polymer electrolyte membrane sandwiched between the catalyst layers of the both electrodes, characterized in that said polymer electrolyte membrane or said ion conductive material contained in the catalyst layer of at least one of said electrodes comprises a sulfonated polyarylene that is a copolymer consisting of 30 to 95 mol % of an aromatic compound unit represented by the following formula (1) and 70 to 5 mol % of an aromatic compound unit represented by the following formula (2) and having sulfonic acid side-chain groups: wherein Ar represents an aryl group, and X represents a divalent electron-attracting group selected from a group consisting of —CO—, —CONH—, —(CF 2 ) p — (wherein p is an integer of 1 to 10, —C(CF 3 )—, —COO—, —SO— and —SO 2 —; and wherein X has the same meaning as that in formula (1), each of X may be identical or different, and a is an integer of 0 to 3.