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.

An object is to provide a nonaqueous solvent, a secondary battery, or a vehicle having a wide usable temperature range and high heat resistance. The nonaqueous solvent of the present invention contains an ionic liquid at greater than or equal to 50 vol % and less than or equal to 95 vol % and a fluorinated cyclic carbonate, and the ionic liquid contains an imidazolium cation. The nonaqueous solvent of the present invention has low viscosity at low temperatures and high heat resistance, thereby having a wide usable temperature range.

A negative electrode material that is used for a negative electrode of a lithium secondary battery containing a non-aqueous electrolyte solution, includes: a first layer that contains lithium metal as a negative electrode active material; and a second layer that is arranged on at least one surface of the first layer. The second layer consists of a compound represented by a general formula M.sub.xA.sub.y (M is an element selected from a group consisting of Al, In, Mg, Ag, Si, and Sn, and A is an element selected from a group consisting of O, N, P, and F, and 0.3<x/y<3). The second layer has a thickness of 100 nm or less.

The present invention provides for an electrolyte composition comprising an ether solvent, an amphiphilic molecule, an electrolyte solvent, and a lithium salt.

The present disclosure relates to prelithiated Si electrodes, methods of prelithiating Si electrodes, and use of prelithiated electrodes in electrochemical devices are described. There are several characteristics of electrode prelithiation that enable the superior battery performance. First, a prelithiated silicon anode is already in its expanded state during SEI formation, and therefore less of the SEI layer breaks down and reforms during cycling. Second, the prelithiated anode has a lower anode potential, which may also help the cycle performance of an electrochemical device. A silicon-based electrode, for use in energy storage devices, may have prelithiated silicon active material with a prelithiation level of above 0% to about 30%, with a lithium source within the energy storage devices providing excess lithium for contributing at least a portion of the prelithiation of the silicon active material.

An electrochemical cell comprises an anode, a cathode and an electrolyte composition, wherein the anode comprises as anode active material a combination of at least a carbon material and a silicon material; and the electrolyte composition comprises a solvent, from 0.5 wt. % to 70 wt. %, based on the total weight of the electrolyte, of a fluorinated acyclic carbonate compound, from 0.5 wt. % to 10 wt. %, based on the total weight of the electrolyte, of a fluorinated cyclic carbonate compound; and an electrolyte salt.

The present invention relates to a sulfolane-based electrolyte composition suitable for Lithium secondary batteries, comprising lithium bis(trifluoromethansolfonyl)imide (LiTFSI) in an amount (x) of 39.0 vol %≤x≤47.5 vol %, fluoroethylene carbonate (FEC) in an amount (y) of 0<y≤15 vol %, equivalent to an amount of 0<y≤14.0 wt. %, relative to the total volume, respectively weight, of the electrolyte composition, and sulfolane, wherein SL/LiTFSI is comprised in a molar ratio (z) of 2≤z≤3.5 as well as its application in a Lithium secondary battery cell.

A lithium secondary battery includes a cathode including a cathode current collector and a cathode active material layer disposed on at least one surface of the cathode current collector, the cathode active material layer including a cathode active material including first cathode active material particles, each of which has a single particle shape; an anode facing the cathode; and a non-aqueous electrolyte including a non-aqueous organic solvent that contains a fluorine-based organic solvent, a lithium salt and an additive.

The present disclosure provides a non-aqueous electrolyte including a lithium salt, an organic solvent, a compound represented by Formula 1 as a first additive, and a polymer including a repeating unit represented by Formula 2-1, Formula 2-2, and Formula 2-3 as a second additive:

##STR00001##

all the variables are described herein.

Provided is a lithium sulfur secondary battery excellent in durability. An electrolytic solution to be used for a lithium sulfur secondary battery having a positive electrode containing a sulfur-containing electrode active material containing at least one selected from the group consisting of simple sulfur, lithium polysulfides (Li.sub.2S.sub.n: 1<n<8) and organosulfur compounds, and a negative electrode containing a material that occludes and releases lithium ions, the electrolytic solution containing a nonaqueous electrolyte and a solvent, wherein the solvent contains vinylene carbonate in a proportion of 10 to 100% by weight.