TECHNOLOGY FOCUS - ELECTRONICS - Preferred Components: The polymer electrolyte or diaphragm has ionic conductivity of higher than 103 S/cm, pore size of 500-2000 nm, film thickness of 5-100 mu m, membrane gas permeability of 1-1000 s/100 cc, longitudinal and transverse tensile strength of 20-200 MPa and shrinkage of less than 2% at 90 degrees C. The single-ion conductive nanoparticles and polymer slurry are mixed in a mass ratio of 0.1:1-5:1. The single-ion conductive nanoparticles include single-ion conductor, which is polymeric lithium borate salt of formula (I), preferably lithium borate salts of formulae (Ia)-(Ik).    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The substrate is polyolefin microporous membrane, polyester non-woven fabric, non-woven nylon fabric, Kevlar (RTM: Para-aramid synthetic fiber) woven fabric, polysulfonamide non-woven fabric, polyurethane non-woven fabric, cellulose non-woven film or polyvinylidene fluoride non-woven fabric. The polymer comprises polyvinyl alcohol, polyvinyl acetate, polyvinylidene fluoride, polyacrylonitrile, poly(methyl methacrylate), polyethylene oxide, polyvinyl butyral, poly(chlorotrifluoroethylene), polystyrene and/or polyvinylidene fluoride-hexafluoropropylene. The preparation method: concentration of the obtained solution is 5-25%; and used solvent is ethyl acetate, methanol, ethanol, glycerol, acetone, formic acid, acetic acid, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, gamma -butyrolactone, dimethyl sulfoxide, sulfolane, dimethyl sulfone, tetrahydrofuran, N-methylpyrrolidone, N,N-dimethylformamide or N,N-dimethylacetamide. Preferred Method: The thickness of scraper blade is 2-150 mu m, drawing tension is 2-50 MPa, coating speed is 500-5000 mm/minute, and the drying temperature is 50-130 degrees C.X1-X4 = -CH2-, -CH2CH2-, -CH(R)-CH2-, -CH2-CH(R)-, -CH(OR)-CH2-, -CH2-CH(OR)-, -C(=O)- or -CH2-C(=O)-;R = 1-5C alkyl or 1-5C fluoroalkyl;Y1 = alkyl group, fluoroalkyl group, aryl group or fluoro-aryl group;G = -(CH2)m-, -(CH2CH2O)m-, -(CH2CH(CH3)O)m- or -(C6H4)m-; andm = not defined.