Preparation and characterization of gel polymer electrolytes based on methyl methacrylate–styrene copolymers

Gel polymer electrolytes (GPEs) are prepared with methyl methacrylate (MMA)–styrene (ST) copolymers and LiPF6 or LiBF4 in ethylene carbonate/dimethyl carbonate. Depending on the molar composition of the copolymer, these gel polymer electrolytes exhibit a different range of mechanical and electrical properties. On the aspect of ionic conductivity and mechanical property, the copolymer comprising about 33 mol% MMA is found to be most desirable. Lithium-ion polymer cells employing GPE containing different electrolyte solution are assembled and their cycling performances are evaluated.