A lithium ion secondary battery includes: a positive electrode, a negative electrode, a separate located between the positive electrode and the negative electrode, and an electrolytic solution. The negative electrode includes a negative electrode active material which contains a material containing silicon and carbon, and a compound containing a first element. The electrolytic solution contains an imide salt which contains the first element and an imide anion. The first element is any one or more elements selected from the group consisting of K, Na, Mg, Ca, Cs, Al, and Zn.

A lithium ion secondary battery includes: a positive electrode, a negative electrode, a separator located between the positive electrode and the negative electrode, and an electrolytic solution. The negative electrode includes a negative electrode active material which contains silicon or a silicon alloy and a compound containing a first element, the electrolytic solution contains an imide salt which contains the first element and an imide anion, and the first element is any one or more elements selected from the group consisting of K, Na, Mg, Ca, Cs, Al, and Zn.

To provide a non-aqueous electrolyte solution, a non-aqueous secondary battery, a cell pack, and a hybrid power system, capable of improving desired battery performance using acetonitrile, the non-aqueous electrolyte solution contains acetonitrile, lithium salt, and cyclic acid anhydride.

A method for manufacturing a lithium secondary battery, including the steps: (S1) forming a preliminary negative electrode by coating a negative electrode slurry including a negative electrode active material, conductive material, binder and a solvent onto at least one surface of a current collector, followed by drying and pressing the negative electrode slurry coated current collector, to form a negative electrode active material layer surface on the current collector; (S2) coating lithium metal foil onto the negative electrode active material layer surface of the preliminary negative electrode in the shape of a pattern in which pattern units are arranged; (S3) cutting the preliminary negative electrode on which the lithium metal foil is pattern-coated to obtain negative electrode units; (S4) impregnating the negative electrode units with an electrolyte to obtain a pre-lithiated negative electrode; and (S5) assembling the negative electrode obtained from step (S4) with a positive electrode and a separator.

A graphene foam-protected selenium cathode layer for an alkali metal-selenium cell, comprising: (a) a sheet or a roll of solid graphene foam composed of multiple pores and pore walls containing graphene sheets, wherein the graphene sheets contain a pristine graphene material having less than 0.01% by weight of non-carbon elements or a non-pristine graphene material having 0.01% to 20% by weight of non-carbon elements, wherein said non-pristine graphene is selected from graphene oxide, reduced graphene oxide, graphene fluoride, graphene chloride, graphene bromide, graphene iodide, hydrogenated graphene, nitrogenated graphene, boron-doped graphene, nitrogen-doped graphene, chemically functionalized graphene, or a combination thereof, wherein the graphene sheets are interconnected or chemically merged together without an adhesive resin; and (b) selenium coating or particles residing in the pores or bonded to the pore walls of the solid graphene foam.

A rechargeable metal halide battery with an optimized active cathode electrolyte solution has high energy density and does not require charging following fabrication. The optimized active cathode electrolyte solution includes (i) a mixture of a metal halide and its corresponding halogen dissolved in an organic solvent at a concentration ratio greater than 0.5 and (ii) an oxidizing gas. The organic solvent is a nitrile-based compound and/or a heterocyclic compound. Glyme may be added to the organic solvent to improve battery performance.

The present invention relates to an electrolyte additive, a battery electrolyte including the electrolyte additive, and a secondary battery, and more particularly, to an electrolyte additive including a compound represented by Chemical Formula 1, an electrolyte including the electrolyte additive, and a secondary battery including the electrolyte. According to the present invention, due to low charging resistance, charging efficiency and output may be improved. In addition, the present invention has an effect of providing a secondary battery having a long lifespan and excellent capacity retention at high temperature.

Disclosed is an electrolyte for a lithium-sulfur battery and a lithium-sulfur battery including the same, more specifically an electrolyte for a lithium-sulfur battery including a lithium salt, a non-aqueous organic solvent, and an additive, wherein the additive includes a sulfide compound. The electrolyte for the lithium-sulfur battery improves the efficiency and stability of the negative electrode, thereby improving the capacity and lifetime characteristics of the lithium-sulfur battery.

Disclosed is a calcium salt, Ca(HMDS).sub.2, where HMDS is the hexamethyldisilazide anion (also known as bis(trimethylsilyl)amide), enables high current densities and high coulombic efficiency for calcium metal deposition and dissolution. These properties facilitate the use of this salt in batteries based on calcium metal. In addition, the salt is significant for batteries based on metal anodes, which have higher specific energies than batteries based on intercalation anodes, such as LiC.sub.6. In particular, a calcium based rechargeable battery includes Ca(HMDS).sub.2 salt and at least one solvent, the solvent suitable for calcium battery cycling. The at least one solvent can be diethyl ether, diisopropylether, methyl t-butyl ether (MTBE), 1,3-dioxane, 1,4-dioxane, tetrahydrofuran (THF), tetrahydropyran, glyme, diglyme, triglyme or tetraglyme, or any mixture thereof.

According to one embodiment, provided is a secondary battery including a positive electrode, a negative electrode, and an electrolyte. The negative electrode includes a niobium-titanium composite oxide having fluorine atoms on at least part of a surface the niobium-titanium composite oxide. An abundance ratio A.sub.F of fluorine atoms, an abundance ratio A.sub.Ti of titanium atoms, and an abundance ratio A.sub.Nb of niobium atoms on a surface of the negative electrode according to X-ray photoelectron spectroscopy satisfy a relationship of 3.5≤A.sub.F/(A.sub.Ti+A.sub.Nb)≤50.