TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Composition: The content of ambient-temperature molten salt in the active material layer is 0.1-5 %mass. The ambient-temperature molten salt contained in the active material layer and an electrolyte solution contains tertiary or quaternary ammonium salt containing tertiary or quaternary ammonium cation, and anion having fluorine atom. The active material layer further contains lithium electrolytic salt. Electrolytic salt contains lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, and/or lithium arsenic hexafluoride. A positive electrode active material contains lithium-nickel complex oxide of formula: LiNixCo1-xO2.x=0-1.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: The solvent further contains halogen-containing chain-like carbonate of formula: R12-C(-R13)(-R11)-O-C(=O)-O-C(-R14)(-R16)-R15 (A) and halogen-containing cyclic carbonate of formula (B). The tertiary or quaternary ammonium cation is cation (a) chosen from group of formulae (a-d), and R2-N+-(R1)(-R3)-R4 (e). The cation (a) is alkyl quaternary ammonium cation, N-methyl-N-propyl piperidinium cation, or N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium cation. The anion which has fluorine atom is borontrifluoride anion (BF4-), fluorosulfonyl anion ((F-SO2)2-N-), trifluorosulfonylimide anion ((CF3-SO2)2-N-). The chain-shaped carbonate (A) is fluoromethyl methyl carbonate or bis(fluoromethyl) carbonate. The cyclic carbonate (B) is 4-fluoro-1,3-dioxolan-2-one or 4,5-difluoro-1,3-dioxolan-2-one. The solvent further contains the cyclic carbonate chosen from formulae (C)-(E) having unsaturated bond, sultone and/or acid anhydride. The cyclic carbonate (C) is vinylene carbonate. The cyclic carbonate (D) is vinyl ethylene carbonate. The cyclic carbonate (E) is ethyl methyl carbonate. The sulfone compound (I) is (1,2,5)oxadithiolane-2,2,5,5-tetroxide or (1,2,6)oxadithiane-2,2,6,6-tetroxide. The sulfone compound (II) is 1,2-oxathiolan-5-one-2,2-dioxide. Electrolytic salt contains transition metal-containing compounds chosen from group of formulae (III), (IV) and (V).R1-R4=aliphatic group, aromatic group, heterocyclic group, or group optionally substituted by substituent;p=4-5;R5-R7=1-5C alkyl, alkoxy, amino, or nitro;R=1-5C alkyl or H;q=0-2;q+r'=3-4;R8=1-5C alkyl;R11-R20=H, halo, alkyl, or haloalkyl, where at least one of R11-R20 is halo or haloalkyl;R21,R22=H or alkyl;R23-R26=H, alkyl, vinyl, or allyl, where at least one of R23-R26 is vinyl or allyl;R27=alkylene;X31-X51=aluminum or group I element or group II element in periodic table;M31-M51=transition metal element, or group XIII element, group XIV element or group XV element in periodic table;R31=halo;Y31=-(O=)C-R32-C(=O)-, -(O=)C-C(R33)2- or -(O=)C-C(=O)-;R32=alkylene, haloalkylene, arylene or haloarylene;R33=alkyl, haloalkyl, aryl, or halo aryl;a=1-4;b=0, 2 or 4;c,d,m,n=1-3;Y41=-(O=)C-(C(R41)2)b4-C(=O)-, -(R43)2C-(C(R42)2)c4-C(=O)-, -(R43)2C-(C(R42)2)c4-C(R43)2-(R43)2C-(C(R42)2)c4-S(=O)2-, -(O=)2S-(C(R42)2)d4-S(=O)2- or -(O=)C-(C(R42)2)d4-S(=O)2-;R41,R43=H, alkyl, halo or haloalkyl, where at least one of R41 and R43 is halo or haloalkyl;R42=H, alkyl, halo or haloalkyl;u,w,y,s,h,i=1 or 2;b4,d4,f,e,e5=1-4;c4,d5=0-4;z,v,g,l=1-3;Rf'=fluoro 1-10C alkyl or fluoro 1-10C aryl;Y51=-(O=)C-(C(R51)2)d5-C(=O)-, -(R52)2C-(C(R51)2)d5-C(=O)-, -(R52)2C-(C(R51)2)d5-C(R52)2-(R52)2C-(C(R51)2)d5-S(=O)2-, -(O=)2S-(C(R51)2)e5-S(=O)2- or -(O=)C-(C(R51)2)e5-S(=O)2-;andR51,R52=H, alkyl, halo or haloalkyl, where at least one of R51 and R52 is halo or haloalkyl.    TECHNOLOGY FOCUS - POLYMERS - Preferred Composition: The active material layer contains polymer containing vinylidene fluoride or acrylonitrile as binder. Preferred Property: The polymer has mean molecular weight of 500000-1000000.