NOVELTY - Nanofiber polymeric electrolyte film, prepared by static spinning method, comprises (in wt.%): electrolyte, polyvinylidene fluoride (50-90) and polyvinylidene fluoride-hexafluoropropylene copolymer (10-50). The porosity of polyvinylidene fluoride and polyvinylidene fluoride-hexafluoropropylene copolymer nanofiber is 45-80%. The electrolyte (1 mol) comprises ethylene carbonate, dimethyl carbonate and diethyl carbonate in the ratio of 1:1:1.    USE - Used as a nanofiber polymeric electrolyte film of polyvinylidene fluoride and polyvinylidene fluoride-hexafluoropropylene copolymer.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for the production of nanofiber polymeric electrolyte film of polyvinylidene fluoride and polyvinylidene fluoride-hexafluoropropylene copolymer comprising: (i) preparing a spinning solution by dissolving polyvinylidene fluoride and polyvinylidene fluoride-hexafluoropropylene copolymer in a mixed solution of N,N-dimethylformamide and acetone, agitating the solution at 45-50 degrees C to obtain the spinning solution of polyvinylidene fluoride and polyvinylidene fluoride-hexafluoropropylene copolymer (8-14 wt%), where the mass ratio of polyvinylidene fluoride to polyvinylidene fluoride-hexafluoropropylene copolymer is 1:1-9:1; (ii) carrying out static spinning method comprising: adding the spinning solution into an injector of the static spinning equipment, fixing the spacing between a spinning jet connected with the injector and a cylindrical receiver, introducing the spinning solution into the spinning jet at a constant speed by an injecting pump, applying high pressure between the spinning jet and the earthed cylindrical receiver, collecting nanofiber film from the cylindrical receiver and drying, maintaining the water content less than 1 ppm and oxygen content less than 1 ppm in a glove case with argon, soaking the copolymer nanofiber film in electrolyte (1 mol) at room temperature, taking out the nanofiber film to obtain nanofiber polymeric electrolyte film, where the electrolyte (1 mol) comprises ethylene carbonate, dimethyl carbonate and diethyl carbonate in the ratio of 1:1:1.