A new type of polymer gel electrolyte: zwitterionic liquid/polar polymer mixture

摘要

An imidazolium cation structure was tethered with an anionic site to form so called "zwitterionic salt". Since the zwitterionic salt dissociates into ions but did not migrate along with the potential gradient, this was used as a non-volatile polar solvent for guest salts. 1-Ethylimidazolium-3-n-propane (or butane)sulfonate was synthesized by one step reaction. This salt was mixed with an equimolar amount of lithium bis(trifluoromethanesulfonyl)imide to provide thermally stable electrolyte solution. This mixture was further mixed with copolymer of vinylidene fluoride and hexafluoropropylene to prepare polymer gel electrolyte with excellent ionic conductivity. Thermal analysis revealed that this polymer gel electrolyte showed no weight loss up to 390 ℃.