Patent ID: 7288336

Claim:
A membrane electrode assembly of a solid polymer electrolyte fuel cell comprising: an anode electrode; a cathode electrode; and a polymer electrolyte membrane that is sandwiched by these electrodes; wherein both the electrodes are formed from a catalyst layer adjacent the polymer electrolyte membrane, and a gas diffusion layer adjacent the catalyst layer, and the catalyst layer of the cathode electrode contains Pt—Co alloys, an electrical conductive, material supporting the Pt—Co alloys, an ion conductive material, and crystalline carbon fibers, wherein the mean lattice plane spacing of the plane of a crystalline carbon fiber is 0.345 nm or less, the fiber diameter thereof is 0.1 μm to 0.5 μm, the fiber length thereof is 10 μm to 40 μm, the bulk density thereof is 0.02 g/cm 3 to 0.10 g/cm 3 , the specific surface area thereof is 5 m 2 /g to 20 m 2 /g, and the specific resistance thereof is 0.025 Ω·cm or less.