A non-aqueous electrolyte secondary battery includes a positive electrode, a negative electrode, and an electrolyte solution, wherein the positive electrode includes a composite oxide including lithium as a first metal, and a second metal X other than lithium; in the composite oxide, the second metal X includes Ni, Al, and Mn; the second metal X does not contain Co or the atomic ratio Co/X of Co to the second metal X is 0.02 or less; and the electrolyte solution contains a chain carboxylic acid ester having 2 to 4 carbon atoms, and a cyclic compound having a ring structure composed of 2 oxygen atoms and 3 to 5 carbon atoms.

A purpose of the present invention is to provide a lithium ion secondary battery having improved battery characteristics. The lithium ion secondary battery according to the present invention comprises a negative electrode comprising a negative electrode active material comprising a silicon material and an electrolyte solution comprising an electrolyte solvent comprising an open chain sulfone compound, a fluorinated cyclic carbonate and an open chain carbonate and a supporting salt comprising LiN(FSO.sub.2).sub.2.

A lithium ion battery according to the present invention comprises a positive electrode, a negative electrode, a positive electrode lead that is connected to the positive electrode, an insulation tape that covers the positive electrode lead, and an electrolyte solution. The insulation tape comprises a base material layer that is mainly composed of an organic material, and a filler layer that is provided on the base material layer; the filler layer contains an oxide compound of an alkaline earth metal; and the electrolyte solution contains fluorine.

A nonaqueous electrolyte battery includes: a positive electrode, a negative electrode, and a nonaqueous electrolyte, wherein the positive electrode contains, as a positive electrode active material, a positive electrode material having a surface composition represented by the following formula (I); the nonaqueous electrolyte contains a halogenated carbonate represented by any of the following formulae (1) to (2) and an alkylbenzene represented by the following formula (3); a content of the halogenated carbonate is 0.1% by mass or more and not more than 50% by mass relative to the nonaqueous electrolyte; and a content of the alkylbenzene is 0.1% by mass or more and not more than 5% by mass relative to the nonaqueous electrolyte

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Disclosed is an electrolyte composition comprising: a) a solvent comprising: i) either a mixture of 1,1,1,3,3,3-hexaflu-oro-2-methoxypropane (HFMP) or of 1,1,1,3,3,3-hexafluoro-2-(fluoromethoxy)propane (HFMFP), of monofluoroethylene carbonate (F1EC) and of 2,2,2-trifluoroethyl methyl carbonate (F3EMC), ii) or a mixture of 1,1,1,3,3,3-hexafluoro-2-methoxypropane (HFMP) or of 1,1,1,3,3,3-hexafluoro-2-(fluoromethoxy)propane (HFMFP), of monofluoroethylene carbonate (F1EC) and of 2,2,2-trifluoroethyl acetate (F3EA), b) at least one lithium salt, the cation of which is the cation of an alkali metal.

Provided is a non-aqueous electrolyte secondary battery capable of achieving both load characteristics and cycle characteristics. The non-aqueous electrolyte secondary battery includes a positive electrode, a negative electrode, and a non-aqueous electrolytic solution. The negative electrode includes a negative electrode active material layer including acrylonitrile-styrene-butadiene rubber. The non-aqueous electrolytic solution includes a propionic acid ester, a halogenated cyclic carbonic acid ester, and at least one of predetermined cyclic sulfuric acid anhydrides. A content of the acrylonitrile-styrene-butadiene rubber in the negative electrode active material layer is 0.5 mass% or more and 2.0 mass% or less.

A non-aqueous electrolyte secondary battery according to an aspect of the present disclosure is provided with a negative electrode having: a negative electrode collector: a first negative electrode mixture layer provided on the surface of the negative electrode collector; and a second negative electrode mixture layer provided on the surface of the first negative electrode mixture layer. Each of the first negative electrode mixture layer and the second negative electrode mixture layer contains graphite particles. The ratio (S2/S1) of the inter-particle porosity (S2) of the graphite particles in the second negative electrode mixture layer to the inter-particle porosity (S1) of the graphite particles in the first negative electrode mixture layer is 1.1-2.0. The ratio (D2/D1) of the filling density (D2) of the second negative electrode mixture layer to the filling density (D1) of the first negative electrode mixture layer is 0.9-1.1.

An electrolyte for a lithium-ion battery includes a primary lithium salt and an organic compound composition. In some designs, the organic compound composition includes (1) fluoroethylene carbonate (FEC), (2) vinylene carbonate (VC), (3) at least one ester (ES), and (4) a nitrile additive composition (NAC) which includes at least one nitrile compound. In some designs, a mole fraction of the NAC in the electrolyte is in a range of approximately 0.1 mol. % to approximately 2.0 mol. %. In some designs, a mole fraction of the at least one ES in the electrolyte is at least approximately 35 mol. %.

Disclosed is a secondary battery, comprising a positive electrode, a negative electrode, and an electrolyte, wherein the electrolyte comprises a lithium salt, an organic solvent, and an additive, wherein the additive comprises a fluorinated compound that accounts for 5-20% of the total mass of the electrolyte, and a polynitrile compound that accounts for 0.2-4% of the total mass of the electrolyte and a sulfate compound that accounts for 0.3-5% of the total mass of the electrolyte; and the negative electrode has a compacted density of not less than 1.55 g/cm3. When the secondary battery is used, the battery can still have both a high temperature characteristic and a low temperature charging ability under the conditions of a higher negative electrode density, thereby having market application prospects, and overcoming the problem of the performance of existing secondary batteries deteriorating when the compacted density of a negative electrode is improved.

A battery includes a positive electrode including a positive electrode active material, a negative electrode, and an electrolytic solution including a nonaqueous solvent. The positive electrode active material includes a compound having a crystal structure belonging to a space group FM3-M and represented by Compositional Formula (1): Li.sub.xMe.sub.yO.sub.αF.sub.β, where, Me is one or more elements selected from the group consisting of Mn, Co, Ni, Fe, Al, B, Ce, Si, Zr, Nb, Pr, Ti, W, Ge, Mo, Sn, Bi, Cu, Mg, Ca, Ba, Sr, Y, Zn, Ga, Er, La, Sm, Yb, V, and Cr; and subscripts x, y, α, and β satisfy the following requirements: 1.7≤x≤2.2, 0.8≤y≤1.3, 1≤α≤2.5, and 0.5≤β≤2. The nonaqueous solvent includes a solvent having at least one fluoro group.