To develop ionic-conductive film-shaped electrolytes with high reliability, we designed and synthesized the following networked polymers with an epoxy/amine curing system using poly(ethylene glycol) as the main skeleton, and examined their fundamental properties such as ionic conductivity, thermal stability, and inflammability. (1) Networked polymers having quaternary ammonium salt structures. (2) Networked polymers having lithium sulfonate salt structures. (3) Networked polymers having lithium sulfonylimide salt structures. (4) Networked polymers swollen with ionic liquid solutions of lithium salts. Consequently, we found that networked polymers swollen with ionic liquid solutions containing lithium salts showed high ionic conductivity and high thermal stability with excellent non-flammability. (C) 2012 Elsevier Ltd. All rights reserved.