Patent ID: 7709116

Claim:
In a PEM fuel cell having at least one cell comprising (a) a pair of opposite polarity electrodes each having a first face exposed to a fuel cell reactant and a second face engaging a membrane-electrolyte interjacent said electrodes, (b) a porous, electrically-conductive media engaging said first face for distributing said reactant over, and conducting electrical current from, said first face, and (c) a current collector engaging said media for conducting electrical current from said media, said current collector comprising a composite having a first conductivity and comprising corrosion-proof, electrically conductive filler dispersed throughout an oxidation-resistant and acid-resistant, water-insoluble polymeric matrix, said current collector, including a face providing a flow field including a plurality of lands and grooves to flow reactant gas through a tortuous path from one side of the current collector to another side, the improvement comprising said current collector comprising a metal substrate supporting said composite and an oxidation-resistant and acid-resistant hyperconductive surface layer on said composite and engaging said media, said hyperconductive surface layer having a second conductivity greater than said first conductivity for shunting electrical current passing through said media into said surface layer to such of said filler as resides at the interface between said surface layer and said composite, and thereby reduce the contact resistance that would otherwise exist between said composite and said media absent said surface layer.