Patent ID: 7727654

Claim:
A membrane-electrode assembly, utilized for solid polymer electrolyte fuel cells, comprising: an anode electrode; a cathode electrode; and a solid polymer electrolyte membrane, the anode electrode and the cathode electrode disposed on opposite sides of the solid polymer electrolyte membrane, wherein the solid polymer electrolyte membrane contains an aromatic polymer which includes a constitutional unit expressed by formula (1) below, a constitutional unit expressed by formula (2-1) or (2-2) below and a constitutional unit expressed by formula (3) below, in the formula (1), Y represents at least a group selected from the group consisting of —CO—, —SO 2 —, —SO—, —CONH—, —COO—, —(CF 2 ) i — (i is an integer of 1 to 10) and —C(CF 3 ) 2 —; Z represents independently a single bond, or at least a group selected from the group consisting of —O—, —S—, —(CH 2 ) j — (j is an integer of 1 to 10) and —C(CH 3 ) 2 —; Ar represents an aromatic group having a substituent expressed by —SO 3 H, —O—(CR 2 ) e SO 3 H or —S—(CR 2 ) e SO 3 H, in which R is an atom or a group selected independently from the group consisting of a hydrogen atom, fluorine atom, alkyl group and partly or fully halogenated alkyl group; e is an integer of 1 to 20; m is an integer of 0 to 10; m′ is an integer of 0 to 10; m″ is an integer of 1 to 100; and k is an integer of 1 to 4; in the formulas (2-1) and (2-2), X represents a divalent group or a single bond; R 11 to R 13 represent independently of each other a hydrogen atom or alkyl group; p is an integer of 1 to 4; and q is an integer of 1 to 4; in the formula (3), R 21 to R 23 represent independently of each other at least an atom or a group selected from the group consisting of a hydrogen atom, fluorine atom, alkyl group, partly or fully halogenated alkyl group, allyl group, aryl group and nitrile group.