Patent ID: 7396610

Claim:
A membrane electrode assembly comprising a proton-conducting membrane, two electrocatalyst layers and two gas diffusion substrates such that the membrane is interposed between the electrocatalyst layers and one gas diffusion substrate is adjacent to each electrocatalyst layer; wherein each gas diffusion substrate comprises a porous electrically conductive sheet material and a gasket member, the sheet material having a central portion and a peripheral portion, the peripheral portion having first and second planar faces; wherein each gasket member is located on the first and second planar faces of the peripheral portion and extends beyond the edge of the peripheral portion in a direction away from the central portion, such that the edge of the peripheral portion is enveloped by the gasket member; wherein each electrocatalyst layer does not extend beyond the central portion of the porous electrically conductive sheet material; and wherein the membrane extends beyond the electrocatalyst layers, such that the membrane contacts the gasket members.