TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Compounds: The negative electrode contains active material in which occlusion/release of lithium is possible. The active material is chosen from carbonaceous material having a D value of lattice surface (002 face) in X-ray diffraction of 0.34 nm or less, oxide of tin, silicon, lead and/or aluminum, alloy of lithium with tin, silicon, lead and/or aluminum, and lithium-titanium oxide. The positive electrode contains active material comprising oxide and/or polyanion compound. The oxide is lithium cobaltate, lithium-manganese complex oxide having spinel structure, lithium-transition metal composite oxide having layer structure containing manganese, nickel and cobalt, and lithium-containing olivine type phosphate.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Compounds: The nonaqueous electrolyte solution further comprises negative-electrode film-formation agent and/or swelling inhibitor. The content of compound (I) is 0.01-1 wt.%. The nonaqueous solvent contains cyclic carbonate chosen from ethylene carbonate and propylene carbonate. The weight ratio of compound (I) and cyclic carbonate is 0.001-0.05. The lithium salt is lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis(trifluoromethanesulfonimide), lithium bis(pentafluoroethanesulfonyl)imide, lithium bis(oxalato)borate, and/or lithium difluoro(oxalato)borate. The negative-electrode film formation agent is a vinylene carbonate derivative of formula (II), a cyclic carbonate of formula (III), an anhydride of formula: R9-C(=O)-O-C(=O)-R10, a carbonate compound of formula: R'9-C(=O)-O-R'10, and/or a benzofuran-dione derivative of formula (IV).R3,R4=H, halo, or 1-12C (halo)alkyl;R5-R14=H, halo, 1-12C (halo)alkyl, or 2-12C alkenyl, with any one of R9 and R10 and at least one of R11-R14 being halo or 1-12C (halo)alkyl;R9+R10+C=cycloaliphatic acid anhydride;R'9=halo, 1-12C (halo)alkyl, or 2-12C alkenyl;andR'10=1-12C (halo)alkyl or 2-12C alkenyl, with any one being halo or 1-12C (halo)alkyl.The swelling inhibitor is cyclic phosphazene derivative of formula (V), gamma -butyrolactone, gamma -valerolactone, gamma -caprolactone, and/or epsilon -caprolactone.R15-R20=H, halo, 1-10C (halo)alkyl, 1-10C (halo)alkoxy, or 6-12C aryl optionally substituted by halo.The nonaqueous solvent contains at least 1 cyclic carbonate and nonaqueous solvent other than that.    TECHNOLOGY FOCUS - POLYMERS - Preferred Component: The separator contains polyethylene as main component.