TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Composition: The positive electrode contains active material including composite metal oxide of cobalt, manganese, nickel, iron, cobalt, nickel, and lithium-containing olivine-type phosphate containing manganese. The negative electrode contains carbon material and active material containing lithium, tin, tin compound, silicon, silicon compound and/or lithium-titanate compound.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: The content of sulfate group-containing compound (I)-(IV) is 0.001-5 %mass. The compound (I) is preferably lithium methyl sulfate, lithium ethyl sulfate, lithium propyl sulfate, lithium butyl sulfate, lithium pentyl sulfate, lithium hexyl sulfate, lithium heptyl sulfate, lithium octyl sulfate, lithium isopropyl sulfate, lithium sec-butyl sulfate, lithium trifluoromethyl sulfate, lithium 2,2,2-trifluoroethyl sulfate, lithium 2,2,3,3-tetrafluoropropyl sulfate, lithium 1,1,1,3,3,3-hexafluoro-2-propyl sulfate, lithium methoxyethyl sulfate, lithium ethoxyethyl sulfate, lithium methoxypropyl sulfate, lithium phenyl sulfate, lithium 4-methylphenyl sulfate, lithium 4-fluorophenylsulfate or lithium perfluorophenyl sulfate, lithium vinyl sulfate, lithium allyl sulfate, lithium propargyl sulfate, lithium-1-oxo-1-ethoxy-1-oxo-propan-2-yl sulfate, lithium 1-oxo-1-(2-propynyloxy)propan-2-yl sulfate, lithium 2-(acryloyloxy)ethyl sulfate, lithium 2-(methacryloyloxy)ethyl sulfate, lithium 2-(methoxycarbonyl)(oxy)ethyl sulfate, lithium (2-oxo-1,3-dioxolan-4-yl)methyl sulfate, lithium 2-(methanesulfonyl)ethyl sulfate, lithium methanesulfonyl sulfate, lithium trifluoromethanesulfonyl sulfate, lithium 2-(trimethylsilyl)ethyl sulfate, lithium 2-cyanoethyl sulfate, lithium 1,3-dicyanopropynyl 2-sulfate, lithium (diethoxyphosphoryl)methyl sulfate, lithium diethoxyphosphoryl sulfate, lithium dibutoxyphosphoryl sulfate or lithium difluoro phosphoryl sulfate. The nonaqueous solvent contains cyclic carbonate or linear carbonate, preferably ethylene carbonate, propylene carbonate, 1,2-butylene carbonate, 2,3-butylene carbonate, vinylene carbonate, vinyl ethylene carbonate, 4-ethynyl-1,3-ioxolane-2-one, 4-fluoro-1,3-dioxolan-2-one, trans or cis-4,5-difluoro-1,3-dioxolan-2-one, methyl ethyl carbonate, methylpropyl carbonate, methyl isopropyl carbonate, methylbutyl carbonate, ethylpropyl carbonate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate or dibutyl carbonate. The nonaqueous electrolyte further contains fluorine-containing compound of formula: F-S(=O)2-O-Si(R51)(R52)-R53 (V). The electrolytic salt is chosen from lithium hexafluorophosphate, lithium tetrafluoroborate, lithium fluorosulfate, lithium trifluoro(methanesulfonyl)(oxy) borate, lithium difluorophosphate, lithium bis(trifluoromethylsulfonyl)imide, lithium bis(fluorosulfuryl)imide, lithium bis(oxalate-O,O')borate or lithium difluorobis(oxalate-O,O')phosphate.R51-R53=1-12C alkyl, 2-3C alkenyl, 6-C8 aryl or S(=O)2F.