Liquid or solid electrolyte compositions are described that comprise a homogeneous solvent system and an alkali metal salt dissolved in said solvent system. The solvent system may comprise a fluoropolymer, having one or two terminal carbonate groups covalently coupled thereto. Batteries containing such electrolyte compositions are also described.
 This invention was made with government support under Grant No. DE-SC0001011 and Contract No. DE-AC02-05CH11231 awarded by the Department of Energy, and Grant No. N00014-10550 awarded by the Office of Naval Research. The US Government has certain rights to this invention.