Edge-protected catalyst-coated diffusion media and membrane electrode assemblies

An assembly for a fuel cell comprising:

• an ionically conductive member;
• an electrically conductive member disposed at a surface of said ionically conductive member and including an outer peripheral edge, and said electrically conductive member comprises a frame-shaped recess around a periphery of said electrically conductive member;
• an electrochemically active material sandwiched between said ionically conductive member and said electrically conductive member, said electrochemically active material extends across said recess to said outer peripheral edge of said electrically conductive member;
• and
• a frame-shaped sealing member disposed in said recess, said sealing member having an inner peripheral edge smaller than said outer peripheral edge of said electrically conductive member and an outer peripheral edge larger than said outer peripheral edge of said electrically conductive member so as to be overlapping said outer peripheral edge of said electrically conductive member wherein said overlapping sufficient to prevent reactant gas cross-over,
• wherein said sealing member has a permeability that is less than a permeability of said ionically conductive member.