Patent ID: 8252476

Claim:
An MEA comprising: a polymer electrolyte membrane; a cathode catalyst layer; and an anode catalyst layer, wherein said cathode catalyst layer has two layers and is arranged on one surface of said polymer electrolyte membrane, wherein said anode catalyst layer has two layers and is arranged on the other surface of said polymer electrolyte membrane, wherein each of said layers of said cathode catalyst layer and said anode catalyst layer contains catalyst loaded particles and a polymer electrolyte, wherein said two layers of said cathode catalyst layer have an identical weight ratio between said catalyst loaded particles and said polymer electrolyte, wherein said two layers of said anode catalyst layer have an identical weight ratio between said catalyst loaded particles and said polymer electrolyte, wherein a unit amount of said catalyst loaded particles contained in the one of said two layers of said cathode catalyst layer which is on a side of the surface are loaded with a greater amount of catalyst than a unit amount of said catalyst loaded particles contained in the other one of said two layers of said cathode catalyst layer which is on a side of the boundary with said polymer electrolyte membrane, and wherein a unit amount of said catalyst loaded particles contained in the one of said two layers of said anode catalyst layer which is on a side of the boundary with said polymer electrolyte membrane are loaded with a greater amount of catalyst than a unit amount of said catalyst loaded particles contained in the other one of said two layers of said anode catalyst layer which is on a side of the surface.