| 摘要 |
PROBLEM TO BE SOLVED: To maintain a wide service temperature range, high mechanical strength and a practical level of conductivity by adding a copolymer of ethylene and tetrafluoroethylene as a third constituent other than a lithium salt electrolyte to a solid electrolyte using a fluorine polymer to be used for a lithium battery and a lithium ion battery. SOLUTION: Vinylidene polyfluoride or a fluorine resin relative to it, fluorine rubber or the like is used as a gel-type fluorine high polymer constituting a solid electrolyte. A copolymer wherein the ratio of ethylene to tetrafluoroethylene is around 40-60:60-40 mol.% is added as a third constituent other than a nonaqueous electrolyte wherein LiPF6 or the like is dissolved in ethylene carbonate or the like. Thereby, a uniform film is so formed without phase separation as to have self-sustention and to be thermally stable at temperatures above 60 deg.C. In addition, the degradation of the conductivity retention property of the electrolyte due to the crystallization of the vinylidene polyfluoride is prevented and sufficient electrolyte concentration can be provided. |
