TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Composition: The positive electrode contains composite metal oxide containing lithium and cobalt, manganese or nickel, or lithium-containing olivine-type phosphate containing cobalt, manganese, iron or nickel as active material. The negative electrode contains carbon material to occlude and discharge lithium metal, lithium alloy or lithium, tin, tin compound, silicon, silicon compound and/or lithium-titanate compound as active material.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: The acyclic lithium salt (I) or (II) is preferably of formula: ((R1-S(=O)(=O))r-M1-(F)s)Li (III), (R1-S(=O)(=O)-O(Y1t))Li (IV) or (O-S(=O)(=O)-R2-S(=O)(=O)-O(Y1)u)2Li (V). The lithium salt (III) is chosen from lithium bis(methanesulfonate)difluoro borate, lithium tris(methanesulfonate)fluoroborate, lithium tetrakis(methanesulfonate)borate, lithium methanesulfonate trifluoroborate, lithium ethane sulfonate trifluoroborate, lithium propane-2-sulfonate trifluoroborate, lithium trifluoromethanesulfonate trifluoroborate, lithium vinyl sulfonate trifluoroborate, lithium 2-propene-1-yl sulfonate trifluoroborate, lithium benzene sulfonate trifluoroborate, lithium 4-ethylbenzene sulfonate trifluoroborate, lithium fluorosulfonate trifluoroborate, lithium methanesulfonate pentafluorophenyl phosphate, lithium ethanesulfonate pentafluorophenyl phosphate, lithium vinyl sulfonate pentafluorophenyl phosphate, lithium 4-methylbenzene sulfonate pentafluorophenyl phosphate, lithium methanesulfonate pentafluorophenyl arsenate, lithium ethanesulfonate pentafluorophenyl arsenate, lithium vinyl sulfonate pentafluorophenyl arsenate and lithium 4-methylbenzene sulfonate pentafluorophenyl arsenate. The lithium salt (IV) is preferably of formula: (H3C-SO3(BF3)t)Li, (CH3-CH2-SO3(BF3)t)Li, (CH(-CH3)(-CH3)-SO3(BF3)t)Li, (CF3-SO3(BF3)t)Li, (CH2=CH-SO3(BF3)t)Li, (F-SO3(BF3)t)Li, (IVa), or (IVb). The lithium salt (V) is chosen from dilithium methane disulfonate bis(trifluoroborate), dilithium ethane-1,2-diyl disulfonate bis(trifluoroborate), dilithium methane disulfonate bis(pentafluorophenyl phosphate), dilithium ethane-1,2-diyl disulfonate bis(pentafluorophenyl phosphate), dilithium methane disulfonate bis(pentafluorophenyl arsenate) and dilithium ethane-1, 2-diyl disulfonate bis(pentafluorophenyl arsenate). The nonaqueous solvent contains cyclic carbonate chosen from ethylene carbonate, propylene carbonate, 1,2-butylene carbonate, 2,3-butylene carbonate, 4-fluoro-1,3- dioxolan-2-one, trans or cis-4,5-difluoro-1,3-dioxolan-2-one, vinylene carbonate, vinyl ethylene carbonate, and 4-ethynyl-1,3-dioxolan-2-one, and linear ester. The linear ester is asymmetrical linear carbonate chosen from methyl ethyl carbonate, methylpropyl carbonate, methyl isopropyl carbonate, methylbutyl carbonate, and ethylpropyl carbonate, or symmetrical linear carbonate chosen from dimethyl carbonate, diethyl carbonate, dipropyl carbonate, and dibutyl carbonate. The nonaqueous electrolyte further comprises nitrile, aromatic compound, isocyanate compound, triple bond-containing compound, sulfinyl group-containing compound, cyclic acetal compound, phosphorus-containing compound, cyclic anhydride and/or cyclic phosphazene compound. The electrolyte salt is chosen from 11 lithium salts e.g. lithium difluorophosphate, lithium hexafluorophosphate, lithium monofiuorophosphate, lithium tetrafluoroborate and lithium fluorosulfonate. The lithium salt further includes lithium hexafluorophosphate, lithium difluorophosphate, lithium tetrafluoroborate, bis(oxalate-O,O')lithium borate, difluoro bis(oxalate-O,O')lithium phosphate and/or lithium sulfonate (FSO3Li and LiN(SO2F)2). The concentration of lithium salt is 0.3-2.5 M with respect to nonaqueous solvent.R1=R;M1=Y;r=1-6;s=0-5;Y1=BF3, PF5 or AsF5;t=1-3;R2=1-6C alkylene in which H is optionally substituted by halo;andu=2-6.(i) When M1 is boron atom, sum of r and s is 4; (ii) When M1 is phosphorus atom or arsenic atom, sum of r and s is 6; (iii) When Y1 is BF3, t is 1-3 and u is 2-6; and (iv) When Y1 is PF5 or AsF5, t is 1 and u is 2.