Patent ID: 7597980

Claim:
An electrolyte composition comprising a sulfonic acid group-containing polymer having at least one structure unit selected from the group consisting of a structure unit represented by formula (1), a structure unit represented by formula (2), a structure unit represented by formula (3), and a structure unit represented by formula (4), (in formulae (1)-(4), Y is, independently for each formula, O, S or a direct bond; R is, independently for each formula, a group having at least either one of an unsaturated bond and an epoxy bond; Ar 1 is, independently for each formula, a sulfonic acid group-containing monovalent aromatic ring that may comprise fluorine or a fluorine-containing substituent group; Ar 2 is, independently for each formula and from each other in each formula, a divalent aromatic ring that may comprise fluorine or a fluorine-containing substituent group; A 3 is, independently for each formula, a divalent group comprising an aromatic ring that may comprise fluorine or a fluorine-containing substituent group; Ar 4 is, independently for each formula, a divalent group comprising a sulfonic acid group-containing aromatic ring that may comprise fluorine or a fluorine-containing substituent group; and Ar 5 is a phenylene group that may have 1 to 4 fluorine atoms as substituents).