Patent ID: 7297433

Claim:
A fuel cell comprising: a laminated, plate shaped membrane electrode assembly including: an electrolyte, first and second electrode layers sandwiching the electrolyte therebetween, and first and second gas-diffusion layers disposed on an outer side of, respectively, the first and second electrode layers, remote from the electrolyte; a first separator plate; and a second separator plate, wherein the first and second separator plates sandwich the membrane electrode assembly therebetween, wherein the first and second gas-diffusion layers are made of an air-permeable metallic material, wherein an arithmetic average roughness Ra of a surface of the air-permeable metallic material contacting one of the first and second electrode layers is in a range of 0.1 μm≦Ra≦1.0 μm, and wherein the air-permeable metallic material comprises a main body defined by a plurality of metal fibers, and wherein a coating made of a noble metal and defining the arithmetic average roughness Ra is formed on each metal fiber on a surface of the main body contacting one of the first and second electrode layers.