POROUS ELECTRODE SUBSTRATE, METHOD FOR MANUFACTURING SAME, AND POLYMER ELECTROLYTE FUEL CELL

摘要

One purpose of this invention is to provide a porous electrode substrate that has a low manufacturing cost, has sufficient conductivity and gas diffusion characteristics, and shows favorable power generation ability with minor structural changes in the porous electrode substrate, as well as a method for manufacturing such a porous electrode substrate. An additional purpose of this invention is to provide a membrane-electrode joint and a solid polymer fuel cell that comprise such a porous electrode substrate. This invention is: a method for manufacturing a porous electrode substrate that comprises a step (1) in which a dispersion fluid comprising a carbon powder (C) and a fluorine-based resin is applied to one or both surfaces of a precursor sheet wherein carbon short fibers (A1) are dispersed in planar orientations with the fiber orientations being substantially within the same plane, and as a result the fluorine-based resin that contains the carbon powder (C) in the vicinity of the surface layer of one side or both sides of the precursor sheet is distributed unevenly to form a precursor sheet with unevenly-distributed fluorine-based resin, and a step (2) in which after the aforementioned step (1) the precursor sheet with unevenly-distributed fluorine-based resin is heat-treated at a temperature 150°C or higher and less than 400°C; a porous electrode substrate manufactured using this manufacturing method; and a solid polymer fuel cell that uses this porous electrode substrate.