This nonaqueous electrolyte secondary battery is provided with: an electrode body that comprises a positive electrode and a negative electrode; and a nonaqueous electrolyte solution that contains a nonaqueous solvent. The ratio of the capacity (Qn) of the negative electrode to the capacity (Qp) of the positive electrode, namely Qn/Qp is 1.4 or more; and the nonaqueous electrolyte solution contains, relative to the total volume of the nonaqueous solvent at 25° C., from 0.5% by volume to 10% by volume of methyl acetate and from 0.01 mole/L to 0.05 mole/L of lithium bisoxalato borate.

A non-aqueous electrolyte according to embodiments of the present invention includes a non-aqueous organic solvents including a monofluoro-based organic solvent and a difluoro-based organic solvent, a lithium salt, and an additive. A weight ratio of the difluoro-based organic solvent relative to the monofluoro-based organic solvent exceeds 3 and is 11 or less.

Disclosed is a rechargeable lithium battery including a positive electrode including a positive active material; a negative electrode including a negative active material; an electrolyte solution including a lithium salt and a non-aqueous organic solvent; and a separator between the positive and the negative electrodes, the separator including a porous substrate and a coating layer positioned on at least one side of the porous substrate. The negative active material includes a Si-based material; the non-aqueous organic solvent includes cyclic carbonate including ethylene carbonate, propylene carbonate, or combinations thereof, the cyclic carbonate being included in an amount of about 20 volume % to about 60 volume % based on the total amount of the non-aqueous organic solvent; and the coating layer includes a fluorine-based polymer, an inorganic compound, or combinations thereof. The rechargeable lithium battery has improved cycle-life and high temperature storage characteristics.

Described herein are solid-state electrolyte materials having high water content. The electrolyte material may include Li, T, X, A, O, and, optionally, Y, wherein T is at least one element selected from the group consisting of P, As, Si, Ge, Al, and B; X and, when present, Y is a halogen, a pseudohalogen, or a superhalogen; and A is at least one element selected from the group consisting of S, Se, and N. The electrolyte material is made generally by exposing the electrolyte precursors to a predetermined amount of water during manufacturing. Also described herein are methods of making the solid-state electrolyte material, processes for making the solid-state electrolyte material, and electrochemical cells comprising the solid-state electrolyte material.

A metal-oxygen battery includes a catholyte with: (i) carbon black; and, (ii) at least one of graphite and graphene, wherein said at least one of graphite and graphene constitutes between 0 wt % and 30 wt % of the total carbon in the catholyte.

The present invention provides an electrochemical cell comprising an anode; an electrolyte having a solubility for sulfur-containing species of less than 15 mM; a cathode comprising greater than 65 wt. % sulfur, wherein the cathode comprises a carbon-sulfur composite material; and wherein the composite material comprises greater than 65 weight % sulfur based on the total weight of the composite material; and wherein the carbon sulfur composite material is formed from an electroconductive carbon material having an average pore volume of 1.5.sup.−3 cm3 g.sup.−1 and an average pore diameter of less than 3 nm.

An electrolyte includes a lithium salt dissolved in a solvent mixture. The solvent mixture may include a first solvent component including an organic solvent having no carbonate groups; a second solvent component configured to improve the electrochemical properties of the first solvent at low temperatures; a third solvent compound configured to promote formation of a passivating SEI layer between the electrolyte and an electrode layer; and a fourth solvent compound configured to stabilize a lithium salt at high temperatures.

An electrolyte for a lithium battery, a lithium battery including the electrolyte, and a method of preparing the electrolyte for a lithium battery. The electrolyte for a lithium battery includes a non-aqueous organic solvent; and about 0.1 wt % to about 1 wt % of lithium nitrate (LiNO.sub.3) based on a total weight of the non-aqueous organic solvent. By using the electrolyte for a lithium battery, lifespan cycle properties of the lithium battery may be improved.

An electrolyte comprising an organic solvent, a lithium salt, and a polymer additive comprised of repeating vinyl units joined to one or more heterocyclic amine moieties is described. The heterocyclic amine contains five to ten ring atoms, inclusive. An electrochemical cell is also disclosed. The preferred cell comprises a negative electrode which intercalates with lithium, a positive electrode comprising an electrode active material which intercalates with lithium, and the electrolyte of the present invention activating the negative and the positive electrodes.

Provided are a nonaqueous electrolytic solution having an electrolyte salt dissolved in a nonaqueous solvent, the electrolyte salt including at least one first lithium salt selected from LiPF.sub.6, LiBF.sub.4, LiN(SO.sub.2F).sub.2, LiN(SO.sub.2CF.sub.3).sub.2, and LiN(SO.sub.2C.sub.2F.sub.5).sub.2, and at least one second lithium salt selected from a lithium salt having an oxalate structure, a lithium salt having a phosphate structure, and a lithium salt having an S═O group, with a sum total of the first lithium salt and the second lithium salt being four or more, and an energy storage device using the same.

This nonaqueous electrolytic solution is not only able to improve electrochemical characteristics at a high temperature and much more improve a discharge capacity retention rate and low-temperature output characteristics after a high-temperature storage test but also able to improve low-temperature input characteristics even for high-density electrodes.