| abstract |
A polymer electrolyte prepared by impregnating a nonaqueous electrolyte with a vinylidene-base copolymer comprising 35-99 mole %, particularly 75-95 mole %, of repeating units derived from vinylidene fluoride, 1-50 mole %, particularly 5-25 mole %, of repeating units derived from tetrafluoroethylene, and 0-10 mole % of a monomer copolymerizable therewith and having a melting point of 80 °C or above, particularly 100 °C or above, a crystallinity of 20-80 %, particularly 20-50 %, and a molecular weight of 50,000-500,000 (in terms of polystyrene in NMP as solvent). |