Vinylidene fluoride copolymer-based polymer electrolyte for nonaqueous battery retaining large proportion of electrolytic solution

A non-aqueous battery, comprising:

• a positive electrode comprising a positive electrode material capable of being doped with and liberating lithium, a negative electrode material capable of being doped with and liberating lithium, and a gel polymer film impregnated with a liquid solution of electrolyte produced by a process comprising:
• dissolving a vinylidene fluoride copolymer and a nonaqueous electrolytic solution with a solvent that can be evaporated to form a solution, wherein the vinylidene fluoride copolymer comprises 80 to 97 wt. % of vinylidene fluoride monomer units and 3 to 20 wt. % of units of at least one monomer copolymerizable with vinylidene fluoride monomer, and has an inherent viscosity of 1.7 to 7 dl/g as measured at 30° C. in a solution at a concentration of 4 g of polymer in 1 liter of N,N-dimethylformamide,
• forming a film of the solution, and
• evaporating the solvent from the film of the solution to form a gel polymer electrolyte in the form of a film comprising the vinylidene fluoride copolymer impregnated with 75-85 wt. % of the nonaqueous electrolytic solution.