POROUS GAS DIFFUSION ELECTRODE AND METHOD OF PRODUCING THE SAME

摘要

A porous gas diffusion electrode for use in an air-metal cell or a hydrogen-air (oxygen) cell comprising an electroconductive porous substrate, which has itself on one surface thereof reaction gas feed channels or is to be used with one surface in contact with reaction gas feed channels during use, and which comprises gas impermeable and electrically insulating seals formed of a tetrafluoroethylene-perfluoroalkyl vinyl ether compolymer provided on the substrate at least at both end portions parallel to said reaction gas feed channels, is capable of positively shielding the gas streams at the end portions parallel to the reaction gas feed channels and maintaining electrical insulation. Such a porous gas diffusion electrode can be prepared by a method comprising applying a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer on the substrate at least at the end portions parallel to the reaction gas feed channels and then subjecting the substrate coated with the copolymer to hot pressure bonding by means of a pressure bonding tool made of a metal previously coated with a fluoride oil to form gas impermeable and electrically insulating seals comprising said copolymer.