Fuel-cell gas diffusion layer and method of forming the same

摘要

This fuel-cell gas diffusion layer includes a conductive porous layer constituted by: porous carbon formed so as to have a porosity distribution substantially uniform in a stacking direction with respect to a membrane electrode assembly; and a PTFE resin arranged dispersedly across the inside of the carbon. When a ratio of a surface of the carbon to a surface that is exposed without being covered with the PTFE resin is defined as an exposure ratio, the exposure ratio of a surface, on a cathode electrode side, of the conductive porous layer, is higher than the exposure ratio, on a diffusion-layer base material side, of the conductive porous layer.

主权项

1. A fuel-cell gas diffusion layer that is obtained by forming a conductive porous layer on one surface of a sheet-shaped diffusion-layer base material and that is stacked on a membrane electrode assembly in a state in which the conductive porous layer is in contact with a catalyst layer of the membrane electrode assembly,
wherein the conductive porous layer comprises: a porous conductive member formed so as to have a porosity distribution substantially uniform in a stacking direction with respect to the membrane electrode assembly and formed so as to have a density of carbon substantially uniform in a stacking direction with respect to the membrane electrode assembly; and a water-repellent member that is arranged dispersedly across an inside of the porous conductive member, and wherein, when a ratio of a surface of the conductive member to a surface that is exposed without being covered with the water-repellent member is defined as an exposure ratio, the exposure ratio of a surface, on a catalyst layer side, of the conductive porous layer, is higher than the exposure ratio, on the diffusion-layer base material side, of the conductive porous layer.