TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The electrolyte solution further comprises difluoro lithium phosphate and monofluoro lithium phosphate. The positive electrode active material comprises lithium-manganese-oxide component (LiMn2-xMaxO4) and (LiMn1-uMeuO2), and complex oxide (zLi2McO3-(1-z)LiMdO2), lithium-iron-phosphate (LiMb1-yFeyPO4), lithium-phosphate-fluoride (Li2MfPO4F), where Ma, Mc, Md and Mf are respectively transition metals, x is 0.2-0.7, Me is transition metal except manganese, u is 0-0.9, z is 0.1-0.9, Mb is manganese and cobalt, and y is 0-0.9, and is transition metals.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The electrolyte solution further comprises silicon-containing compounds of formulae (II) and/or (III). The sulfur-containing organic compound comprises structures of formulae (IV) and/or (V). The electrolyte solution further comprises sulfonic acid ester derivatives of formulae (VI)-(IX), and sulfite derivative. The electrolyte solution comprises sulfonic acid ester derivatives (VI) and/or (VII), and a sulfite derivative as the sulfur-containing organic compound. The sulfonic acid ester derivatives (VI) and/or (VII) are selected from 1, 3- propane sultone, 1, 3- propene sultone, and 1,4-butane sultone. The sulfonic acid ester derivatives (VIII) and/or (IX) are selected from ethylene glycol sulfuric ester, 1,2-propanediol sulfuric ester, and 1,3-propanediol sulfuric ester. The sulfite derivative is selected from ethylene sulfite, propylene sulfite and butylene sulfite.M = phosphorus atom or boron atom;w = 0 or 1, when M is a phosphorus atom;w = 0 when M is a boron atom;R4, R5 = 1-10C alkyl, 1-10C alkoxy (both optionally substituted), OH, OLi, 3-10C siloxy, 6-15C aryl or 6-15C aryloxy;R6 = 1-20C organic group (optionally substituted);R7-R12 = 1-4C hydrocarbon having hydrogen or fluorinated substituent;R10+R11 = double bond;x = 1-3, where R8 may be the same as R7 respectively, or may mutually differ from each other, when x is 2 or 3;Ra, Rb = 1-20C organic group;R13-R16 = H or 1-4 alkyl having fluorinated substituent;y, z = 0 or 1; andR17-R20 = H or 1-4C alkyl having fluorinated substituent.Preferred Composition: The concentration of the sulfur-containing organic compound is 0.1-10 mass%. The concentration of the silicon-containing compound (I) is 0.01-10 mass%. EXAMPLE - No suitable example given.