Patent ID: 7390595

Claim:
A method for preparing a cross-linked polymer in an electrolyte composition comprising a liquid electrolyte and a cross-linked polymer comprising: reacting a nitrogen-containing polymer compound containing a nitrogen atom to be quaternized with an electrophilic reagent having at least two groups that react with the nitrogen-containing polymer compound so as to obtain the cross-linked polymer and forming the electrolyte composition containing the cross-linked polymer and a liquid electrolyte comprised of a salt and a solvent for the salt having high ion conductivity, wherein the nitrogen-containing polymer compound is a polymer having a repeating unit represented by formula (1-a) wherein R 1 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; Z represents a nitrogen-containing heterocyclic group containing a nitrogen atom to be quaternized; L represents a direct bond or a divalent linking group; A represents a repeating unit formed by 1) esters derived from acrylic acid or α-alkylacrylic acid, or 2) amides derived from acrylic acid or α-alkylacrylic acid, or 3) aromatic vinyl compounds; and x and y each represent a molar ratio of the respective repeating units, x being 10 to 95 mol %, and y being 5 to 90 mol %.