Composite polymer electrolyte membrane, and catalyst-coated membrane, membrane electrode assembly, and polymer electrolyte fuel cell using the composite polymer electrolyte membrane

Abstract

A composite polymer electrolyte membrane includes a composite layer of an aromatic hydrocarbon-based polymer electrolyte and a fluorine-containing polymer porous membrane, wherein a ratio (O/F ratio) of an atomic composition percentage of oxygen O (at %) to an atomic composition percentage of fluorine F (at %) on an outermost surface of the fluorine-containing polymer porous membrane as measured by X-ray photoelectron spectroscopy (XPS) is 0.20 or more to 2.0 or less, and the aromatic hydrocarbon-based polymer electrolyte in the composite layer forms a phase separation structure.

Dependencies are inferred from the claim text.