| 摘要 |
PROBLEM TO BE SOLVED: To retain a large quantity of an organic electrolytic solution and to reduce the degree of deterioration of a resin by including a vinylidene fluoride-tetrafluoroethylene copolymer obtained by copolymerizing tetrafluoroethylene in a specified ratio and an organic solvent capable of dissolving a lithium salt. SOLUTION: A vinylidene fluoride-tetrafluoroethylene copolymer, that is one component of a gel composition is obtained by copolymerizing 1-15 wt.% of tetrafluoroethylene, and preferably it has the number average molecular weight of about 200,000-700,000. The organic solvent for dissolving a lithium salt compound preferably consists of a carbonate, and this is obtained by adding a low viscosity solvent to a high dielectric constant solvent and regulating the electrolytic viscosity. For example, ethylene carbonate or propylene carbonate is used as the high dielectric constant solvent, and dimethylcarbonate or diethylcarbonate is used as the low viscosity solvent. |
