Patent ID: 7473486

Claim:
A catalyst-coated membrane comprising a hydrogen ion conductive polymer electrolyte membrane, a cathode catalyst layer and an anode catalyst layer sandwiching said polymer electrolyte membrane, said cathode catalyst layer and said anode catalyst layer each comprising: a catalyst-carrying carbon comprising a carbon powder and an electrode catalyst carried on said carbon powder; and a hydrogen ion conductive polymer electrolyte attached to said catalyst-carrying carbon, wherein at least said cathode catalyst layer comprises at least two layers, the ratio (WP/W Cat-C ) of the weight of said polymer electrolyte (W P ) to the weight of said catalyst-carrying carbon (W Cat-C ) is decreased from an innermost layer positioned closest to said polymer electrolyte membrane toward an outermost layer positioned farthest from said polymer electrolyte membrane in said cathode catalyst layer, and said ratio (W P /W Cat-C ) in said innermost layer is 0.8 to 3.0 and said ratio (W P /W Cat-C ) in said outermost layer is 0.2 to 0.6, the ratio (W Cat-innermost /W Cat-total ) of the weight of said electrode catalyst contained in said innermost layer (W Cat-innermost ) to the weight of said electrode catalyst contained in said entire cathode catalyst layer (W Cat-total ) is 1/10 to ⅓.