COMPOSITION FOR POLYMER GEL ELECTROLYTE, POLYMER GEL ELECTROLYTE, AND SECONDARY BATTERY AND ELECTRIC DOUBLE LAYER CAPACITOR EACH EMPLOYING THE ELECTROLYTE

A polymer gel electrolyte composition is composed primarily of (A) a polymeric compound having an average degree of polymerization of at least 20 which contains polyvinyl alcohol units of the following general formula (1): wherein n is a number of at least 20 and some or all of the hydroxyl groups on the polyvinyl alcohol units are substituted with cyanated monovalent hydrocarbon groups; (B) an ion-conductive salt; (C) a compound having at least two reactive double bonds on the molecule; and (D) an organic electrolyte solution.