Abstract: An excellent polymer electrolyte composition has excellent chemical stability of being resistant to strong oxidizing atmosphere during operation of fuel cell, and achieves excellent proton conductivity under low-humidification conditions, excellent mechanical strength and physical durability. A polymer electrolyte membrane, a membrane electrode assembly, and a polymer electrolyte fuel cell each use the same. The polymer electrolyte composition contains an ionic group-containing polymer (A), a phosphorus-containing additive (B), and a nitrogen-containing aromatic additive (C), the phosphorus-containing additive (B) and the nitrogen-containing aromatic additive (C) being a compound represented by specific structural formulae.

Abstract: A method of producing an assembly including a polymer electrolyte membrane includes a step of preliminary pressure application wherein a pressure is continuously applied to a recipient sheet including a polymer electrolyte membrane and an assembling sheet including an assembling layer to be assembled to at least one surface of the recipient sheet, the pressure being applied to the recipient sheet and the assembling layer of the assembling sheet being in contact with each other, and a step of heated pressure application wherein the recipient sheet and the assembling sheet after the preliminary pressure application step are subjected to continuous pressure application with heating.

Abstract: The present invention provides: a polymer electrolyte composition which can achieve excellent proton conductivity under slightly humidified conditions, excellent mechanical strength and excellent physical durability, has excellent practicality, and can be produced using a nitrogen-containing additive, wherein the nitrogen-containing additive can prevent the elution of the additive under a strongly acidic atmosphere during the operation of a fuel cell, has excellent chemical stability so as to tolerate a strongly acidic atmosphere, can be dissolved in various general-purpose organic solvents, has superior processability, can be mixed with an ionic-group-containing polymer, can prevent the occurrence of phase separation during the formation of a film, and can prevent the formation of an island-in-sea-like phase separation structure or the occurrence of bleeding out during the formation of a film; and a polymer electrolyte membrane, a membrane electrode assembly and a polymer electrolyte fuel cell, each of which

Abstract: An excellent polymer electrolyte composition has excellent chemical stability of being resistant to strong oxidizing atmosphere during operation of fuel cell, and achieves excellent proton conductivity under low-humidification conditions, excellent mechanical strength and physical durability. A polymer electrolyte membrane, a membrane electrode assembly, and a polymer electrolyte fuel cell each use the same. The polymer electrolyte composition contains an ionic group-containing polymer (A), a phosphorus-containing additive (B), and a nitrogen-containing aromatic additive (C), the phosphorus-containing additive (B) and the nitrogen-containing aromatic additive (C) being a compound represented by specific structural formulae.

Abstract: The present invention provides: a polymer electrolyte composition which can achieve excellent proton conductivity under slightly humidified conditions, excellent mechanical strength and excellent physical durability, has excellent practicality, and can be produced using a nitrogen-containing additive, wherein the nitrogen-containing additive can prevent the elution of the additive under a strongly acidic atmosphere during the operation of a fuel cell, has excellent chemical stability so as to tolerate a strongly acidic atmosphere, can be dissolved in various general-purpose organic solvents, has superior processability, can be mixed with an ionic-group-containing polymer, can prevent the occurrence of phase separation during the formation of a film, and can prevent the formation of an island-in-sea-like phase separation structure or the occurrence of bleeding out during the formation of a film; and a polymer electrolyte membrane, a membrane electrode assembly and a polymer electrolyte fuel cell, each of which