Patent ID: 8263710

Claim:
A solid polymer electrolyte material made of a copolymer comprising a repeating unit based on a fluoromonomer A which gives a polymer having an alicyclic structure in its main chain by radical polymerization, and a repeating unit based on a fluoromonomer B of the following formula (1), wherein the repeating unit based on a fluoromonomer A is represented by the following formula (4): wherein s is 0 or 1, each of R f4 , R f5 , R f6 and R f7 , which may be the same or different, is a fluorine atom or to a C 1-5 perfluoroalkyl group (provided that R f4 and R f5 may be connected to form a spiro ring when s is 0), and R f8 is a fluorine atom, a C 1-5 perfluoroalkyl group or a C 1-5 perfluoroalkoxy group; CF 2 ═CF(R f ) j SO 2 X (1) wherein j is 0 or 1, X is a fluorine atom, a chlorine atom or OM {wherein M is a hydrogen atom, an alkali metal atom or a group of NR 1 R 2 R 3 R 4 (wherein each of R 1 , R 2 , R 3 and R 4 which may be the same or different, is a hydrogen atom or a monovalent organic group)}, and R f is a C 1-20 polyfluoroalkylene group having a straight chain or branched structure which optionally contains at least one ether oxygen atom.