GAS-DIFFUSION ELECTRODE BASE MATERIAL AND METHOD FOR MANUFACTURING SAME

An object of the present invention is to provide a gas-diffusion electrode substrate which is suppressed in reduction of gas diffusibility due to blockage of pores and is also suppressed in deterioration in power generation performance, and is further excellent in drainability of water to the outside of the system. The present invention provides a gas-diffusion electrode substrate including an electrode substrate and a microporous layer (hereinafter referred to as an MPL) disposed on one surface of the electrode substrate, wherein the gas-diffusion electrode substrate has a thickness of 110 µm or more and 240 µm or less, and where a cross section of the gas-diffusion electrode substrate is divided into a part having the MPL and a part having no MPL, and the part having no MPL is further equally divided into a part in contact with the MPL (hereinafter referred to as a CP1 cross section) and a part not in contact with the MPL (hereinafter referred to as a CP2 cross section), the CP1 cross section has an F/C ratio of 0.03 or more and 0.10 or less and the CP2 cross section has an F/C ratio less than 0.03, wherein "F" is a mass of a fluorine atom, and "C" is a mass of a carbon atom.