TECHNOLOGY FOCUS - POLYMERS - Preferred Properties: A weight average molecular weight of the polyvinylidene fluoride-based polymer is 50000-1000000 and a polymer dispersion degree is 1-4. A viscosity of the electrolytic slurry is 1000-100000 cps. Preferred Composition: The polyvinylidene fluoride-based polymer is a copolymer of polyvinylidene fluoride and hexafluoro propane, and an amount of hexafluoro propane is 2-30 wt.% based on the total amount of the copolymer. An amount of the ethylene carbonate is 20-80 wt.% based on the total amount of electrolytic solvent. An amount of propylene carbonate or the gamma-butyrolactone is 60 wt.% or less based on the amount of the ethylene carbonate. A concentration of the electrolytic salt with respect to the electrolytic solvent is 0.5-2M. Preferred Method: The step of mixing the polyvinylidene fluoride-based polymer with the electrolytic solvent is implemented at room temperature. The electrolytic slurry is prepared by stirring the mixture at 60-150degreesC for 5 minutes to 2 hours. The step of solidifying the electrolytic slurry is implemented by coating the electrolytic slurry on a substrate or a molded film and then drying.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The electrolytic solvent consists of ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), or gamma-butyrolactone (gamma-BL).    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The electrolytic salt is lithium perchlorate (LiClO4), lithium trifluoromethane sulfonate (LiCF3SO3), lithium borofluoride (LiBF4), lithium hexafluorophosphate (LiPF6), or lithium arsenic hexafluoride (LiAsF6). EXAMPLE - 1 g of Kynar 2801 as a polyvinylidene (PVdF)-based copolymer and 8 g of a mixture solution of ethylene carbonate/dimethyl carbonate/ethyl methyl carbonate (1/0.8/0.5 by weight) in which 1M LiPF6 was dissolved, were mixed. The mixture was stirred at 130degreesC for 1 hour. The obtained polymer electrolytic slurry was cast on a substrate. The thickness of the cast film was 60 mum and the toughness was excellent. The ionic conductivity of the polymer electrolyte was 1.8x10-3 S/cm. The cast polymer electrolyte had good mechanical strength and a good adhesiveness to the electrode. A cell was manufactured by integrating a cathode, polymer electrolyte and an anode. The cell was additionally impregnated with a mixture solution of ethylene carbonate/propylene carbonate/ethyl methyl carbonate (0.4/0.3/0.3 by weight) in which 1M LiPF6 was dissolved, and was sealed under a vacuum.