ELECTRODE DESIGN WITH OPTIMAL IONOMER CONTENT FOR POLYMER ELECTROLYTE MEMBRANE FUEL CELL

摘要

A method of making a membrane electrode assembly for a fuel cell, a membrane electrode assembly, a fuel cell and a fuel cell system. The method includes preferentially adsorbing an ionomer and electrocatalyst mixture onto the surface of a porous fuel cell substrate by appropriate treatment of the mixture prior to or contemporaneous with placement of the mixture onto the substrate. This promotes retention of the ionomer-coated electrocatalyst at or near the surface of the substrate where catalytic activity between it and a proton exchange membrane is designed to take place. Retention of the ionomer-coated electrocatalyst near these interfacial regions by the present invention is preferable to having the ionomer and electrocatalyst be significantly absorbed into the substrate.

主权项

1. A method of making a membrane electrode assembly for a fuel cell, said method comprising:
combining an ionomer and an electrocatalyst together with a first solvent to create a first catalyst ink and then removing said first solvent from said first catalyst ink to create a dried ionomer-coated electrocatalyst; treating said ionomer-coated electrocatalyst such that upon subsequent placement thereof onto a porous substrate, said ionomer-coated electrocatalyst is preferentially adsorbed thereon rather than absorbed therein; applying at least one layer of said treated ionomer-coated electrocatalyst to said porous substrate; and placing said porous substrate with said treated ionomer-coated electrocatalyst onto opposing sides of a proton-conductive membrane such that said membrane electrode assembly is defined thereby.