POLYMER ELECTROLYTE COMPOSITION, AND POLYMER ELECTROLYTE MEMBRANE, MEMBRANE-ELECTRODE ASSEMBLY, AND POLYMER ELECTROLYTE FUEL CELL EACH USING SAME

摘要

Provided are: a practically excellent polymer electrolyte composition which has excellent chemical stability capable of withstanding a strong oxidizing atmosphere during the operation of a fuel cell, while achieving excellent proton conductivity under low humidification conditions, excellent mechanical strength and excellent physical durability; and a polymer electrolyte membrane, a membrane electrode assembly and a solid polymer fuel cell, each of which uses the polymer electrolyte composition. A polymer electrolyte composition of the present invention contains at least (A) an ionic group-containing polymer and (B) a phosphorus-containing additive. This polymer electrolyte composition is characterized in that the phosphorus-containing additive (B) is composed of at least one compound that is selected from among phosphine compounds and phosphinite compounds. A polymer electrolyte membrane, a membrane electrode assembly and a solid polymer fuel cell of the present invention are characterized by being configured using the polymer electrolyte composition.