CARBON SHEET, GAS DIFFUSION ELECTRODE BASE MATERIAL, AND FUEL CELL

摘要

One purpose of the present invention is to provide a carbon sheet suitable for use in gas diffusion electrode base materials such that, in a gas diffusion electrode base material, anti-flooding properties are superior because of large improvements in gas diffusibility and drainage properties, high electricity generating performance can be expressed even when operated at comparatively low temperatures and in a high current density region, and further, mechanical properties, conductivity, and heat conductivity are superior. One embodiment of this carbon sheet for achieving the purpose above is a porous carbon sheet containing carbon fiber and a binder, wherein the carbon sheet is characterized in that when measuring the depth distribution of the surfaces and letting surface layer area ratio X be the proportion of the surface area for parts with a depth of 20 µm or less in a measured surface area on one surface and surface layer area ratio Y be the proportion of the surface area for parts with a depth of 20 µm or less in a measured surface area on the other surface, the surface layer area ratio X is larger than the surface layer area ratio Y and that difference is 3 - 12%.