Polymer electrolyte composition

The polymer electrolyte composition comprising a molten salt and an aromatic polymer having a carbonyl bond and/or a sulfonyl bond in the main chain thereof and containing a cation exchange group, wherein the aromatic polymer is an aromatic polyether sulfone block copolymer and/or an aromatic polyether ketone block copolymer, the aromatic polyether sulfone block copolymer and the aromatic polyether ketone block copolymer comprising a hydrophilic segment containing a cation exchange group and a hydrophobic segment containing no cation exchange group in which the hydrophobic segment has a structural unit represented by chemical formula (6):

• wherein Z3 represents C═O or O═S═O;
• and p represents an integer of 3 to 1500, and the hydrophilic segment has a structural unit represented by chemical formula (7):
• wherein Z4 represents C═O or O═S═O;
• q represents an integer of 3 to 1500;
• Ar4 represents a divalent aromatic group composed of an aromatic ring, the aromatic ring, is not bonded to an electron drawing group other than a cation exchange group and that which forms the molecular chain of the prepolymer hydrophilic segment or the main chain of the copolymer;
• and a part or all of the aromatic group residues are substituted with a cation exchange group, the molten salt has an ammonium ion as a cation component, the molten salt is present in an amount of 3 to 90% by weight, and the cation exchange group is a sulfonic acid group or a carboxyl group, and the cation exchange group-containing block copolymer has an ion exchange capacity of 0.1 to 3 meq/g.

A polymer electrolyte composition comprising a molten salt and a polystyrene polymer wherein the polystyrene polymer has a structural unit represented by chemical formula (12):

• wherein X represents a cation exchange group, and/or a structural unit represented by chemical formula (13):
• wherein Y represents a cation exchange group,
• the molten salt has an ammonium ion as a cation component,
• the molten salt is present in an amount of 3 to 90% by weight, and the polystyrene polymer has an ion exchange capacity of 0.3 to 3 meq/g.