COMPOSITE POLYMER ELECTROLYTE MEMBRANE, AS WELL AS ELECTROLYTE MEMBRANE HAVING CATALYST LAYER, MEMBRANE ELECTRODE ASSEMBLY, AND SOLID POLYMER FUEL CELL IN WHICH SAID COMPOSITE POLYMER ELECTROLYTE MEMBRANE IS USED

摘要

An object of the present invention is to provide a polymer electrolyte membrane, which has excellent proton conductivity even under a low humidity condition and a low temperature condition, further is excellent in the mechanical strength and the physical durability, and is capable of achieving the high power, the high energy density, and the long-term durability when being used as a polymer electrolyte fuel cell; and a membrane electrode assembly and a polymer electrolyte fuel cell, using the polymer electrolyte membrane, the present invention being a composite polymer electrolyte membrane including a composite layer of an aromatic hydrocarbon-based polymer electrolyte and a fluorine-containing polymer porous membrane, in which a ratio (O/F ratio) of an atomic composition percentage of oxygen O (at%) to an atomic composition percentage of fluorine F (at%) on the outermost surface of the fluorine-containing polymer porous membrane as measured by X-ray photoelectron spectroscopy (XPS) is 0.2 or more to 2.0 or less, and further the aromatic hydrocarbon-based polymer electrolyte in the composite layer forms a phase separation structure.