TECHNOLOGY FOCUS - ELECTRONICS - Preferred Composition: The lithium ion battery further contains cathode containing lithium transition metal oxide of formula: LiMnxMyNzO2, where element (M) is cobalt or nickel, element (N) is chosen from cobalt, nickel, aluminum, boron, iron, magnesium and chromium, sum of x, y and z is 1, x is 0.2-0.6, y is 0.2-0.6 and z is 0.05-0.4.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Composition: The electrolyte contains lithium tetrafluoroborate or lithium hexafluoroborate, preferably lithium hexafluoroborate.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: The content of cyclic carbonate and linear carbonate in the solvent is 18-30 volume% and 70-82 volume%, respectively. The content of additive with respect to total content of solvent and electrolyte is 0-20 wt.%. The content of electrolyte with respect to total content of additive and solvent is 0.5-2 mol/L. The cyclic carbonate is ethylene carbonate or propylene carbonate, preferably ethylene carbonate. The linear carbonate is dimethyl carbonate or ethyl methyl carbonate, preferably ethyl methyl carbonate. The volume ratio of ethylene carbonate to ethyl methyl carbonate is 1-1.4. The weight ratio of additive with respect to carbon material is 1-3. The additive is chosen from phosphate trialkyl derivative of formula (III) (preferably, trimethyl phosphate), phosphorus compound of formula (IV), cyclic sulfone derivative of formula (V) (preferably, sulfolane), cyclic sultone derivative of formula (VI) (preferably, propane sultone) and chain-shaped ester derivative of formula: R20-CH2-C(=O)-O-CH3 (preferably, methyl fluoroacetate). The phosphorus compound is chosen from tris(2,2,2-trifluoroethyl)phosphite, tris(2,2,2-difluoroethyl)phosphite, tris(2,2,2-fluoroethyl)phosphite, tris(2-fluoroethyl-2-difluoroethyl-trifluoroethyl)phosphite and ethyl phosphite.R7-R19=R1;andR20=1-3C alkyl, haloalkyl, vinyl, or halo.Preferred Property: The direct current resistance of electrolyte solution excluding additive is 0.5-1 ohm.