Electrolyte membrane, catalyst-coated electrolyte membrane and transfer sheet used for production thereof, membrane electrode assembly, water electrolysis device, and method of producing catalyst-coated electrolyte membrane

Abstract

An object of the present invention is to provide an electrolyte membrane having an excellent joining property between an electrolyte membrane and a catalyst layer. The present invention mainly relates to an electrolyte membrane including a layer (A) containing a polymer electrolyte, and a layer (B) on at least one of the faces of the layer (A), wherein porosity (X1) in an interface region of the layer (B), on the layer (A) side, is higher than porosity (X2) in another interface region of the layer (B), on the opposite side to the layer (A).

Dependencies are inferred from the claim text.