Patent ID: 6733915
Filing Date: 2004-05-11
Classification: H01M,Y02E,Y02P

Abstract:
A gas diffusion backing adapted for use in fuel cells consisting essentially of a porous first layer and a microporous second layer in electrically conductive contact therewith, said first layer consisting essentially of a porous carbonaceous paper or fabric comprising carbon fibers, wherein the carbon fibers comprise at least 50% by volume of the layer, said fibers being at least partially coated by a first fluorinated polymer disposed thereupon, and said second layer consisting essentially of a second fluorinated polymer having carbon particles intermixed therewith, the first and second fluorinated polymers (i) being the same or different, (ii) each being a melt processable polymer selected from the group consisting of:(a) amorphous polymers having a glass transition temperature (Tg) of less than about 250Â° C.; (b) crystalline or semi-crystalline polymers having a melting point of less than about 315Â° C.; and (c) mixtures thereof.