TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The lithium salt is at least one of LiPF6, LiBF4, LiClO4, LiCF3SO3, LiC4F9SO3, LiN(CF3SO2)2, LiAsF or LiN(SO2C2F5)2. The porous film and/or the electrolyte additionally comprise an inorganic filler. The inorganic filler is at least one of titanium dioxide (TiO), silicon dioxide (SiO2), alumina (Al2O3), lithium aluminate (gamma -LiAlO2) or zeolite. The compound enabling intercalation and deintercalation of lithium is at least one of LiCoO2, LiMnO2, LiNiO2, LiCrO2 or LiMn2O4.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The lithium salt is at least one of LiPF6, LiBF4, LiClO4, LiCF3SO3, LiC4F9SO3, LiN(CF3SO2)2, LiAsF or LiN(SO2C2F5)2. The porous film and/or the electrolyte additionally comprise an inorganic filler. The inorganic filler is at least one of titanium dioxide (TiO), silicon dioxide (SiO2), alumina (Al2O3), lithium aluminate (gamma -LiAlO2) or zeolite. The compound enabling intercalation and deintercalation of lithium is at least one of LiCoO2, LiMnO2, LiNiO2, LiCrO2 or LiMn2O4.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The weight ratio of the first polymer to the second oligomer is 95:5 - 35:65. The poly (ethylene oxide-co-ethylene carbonate) copolymer, the molar ratio of ethylene oxide unit to ethylene carbonate unit is 9:1 - 1:9. EXAMPLE - A poly(vinylidene fluoride-co-hexafluoropropylene) (P(VdF-HFP)) copolymer (M: 455000, Tg: 155 - 160degreesC), Poly(ethylene oxide-ethylene carbonate) (P(EO-EC)) copolymer with at least one terminal groups substituted by chlorine atom, and an acetone solvent were placed in a beaker and sufficiently dissolved with heating at 50degreesC. Then, ethyleneglycol non-solvent was added to the reaction mixture, heated and stirred at 50degreesC for 5 hours, to obtain a uniform mixed solution. At this time, the volume ratio of acetone to ethyleneglycol was set to 90:10 and the total polymer concentration of the mixed solution was set to 10 wt.%. The wt. ratio of the P (VdF-HFP) copolymer to the P(EO-EC) copolymer was: 10:0, 9:1, 8:2, 7:3, 6:4, and 5:5. The mixed solution was left stand at 50degreesC for 2 hours to accomplish air bubble removal and thermal equilibration and then cast on a glass plate. The resultant structure was subjected to sufficient evaporation of a solvent and then repeated cleaning with methanol to remove a residual non-solvent. Porous films (p1) thus produced were dried in a 50degreesC vacuum oven for 24 hours. P(EO-EC) copolymer (1 g) with at least one terminal groups substituted by chlorine atom and LiCF3SO3 lithium salt (0.23 g) were added to acetone (20 g) and stirred. In the case of using an inorganic filler, TiO2 powders (0.015 g) were further added to a mixture (0.985 g) of the P(EO-EC) copolymer with at least one terminal groups substituted by chlorine atom, and the lithium salt. The mixture was dried to remove substantially completely acetone to obtain a viscous electrolyte composition. The viscous electrolyte composition with flowability was spread on upper surfaces of (p1). At this time, the viscous electrolyte composition was heated at 80degreesC to decrease viscosity and thus increase flowability. Then, strong vacuum was applied to lower surfaces of the porous films using a vacuum pump so that the P(EO-EC) and lithium salt-containing oligomer electrolyte composition was infiltrated into pores of the porous films, to obtain solvent-free polymer electrolytes