Methods of applying as-prepared alkaline source materials for a secondary battery. The cathode includes an alkaline source material with or without coating including an alkali metal oxide, an alkali metal sulfide, an alkali metal salt, or a combination of any two or more thereof. An as-prepared spread coating layer for a secondary battery, the coating layer includes an alkaline source material, including an alkali metal oxide, an alkali metal sulfide, and an alkali metal salt, with or without coating, a conductive carbon, a catalyst, or a combination of any two or more thereof. An as-prepared electrolyte for a secondary battery, the electrolyte includes an alkaline source material including an alkali metal oxide, an alkali metal sulfide, an alkali metal salt, or a combination of any two or more thereof.

An electrolyte for a lithium secondary battery, and a lithium secondary battery including the same are disclosed herein. In some embodiments, an electrolyte includes a lithium salt having a concentration of 1.6 M to 5 M, an oligomer including a unit represented by Formula A, and an organic solvent including a cyclic carbonate-based compound and an acetate-based compound, wherein the cyclic carbonate-based compound is present in an amount of 6 vol % to 19 vol % based on the total volume of the organic solvent.

A non-aqueous electrolyte for a lithium secondary battery and a lithium secondary battery including the same are disclosed herein. In some embodiments, the non-aqueous electrolyte includes a lithium salt, an organic solvent, a compound represented by Formula 1 as a first additive, lithium difluorophosphate as a second additive, and a compound represented by Formula 2 as a third additive.

The present disclosure provides a non-aqueous electrolyte including an additive for a non-aqueous electrolyte, which is represented by the following Chemical Formula 1:

##STR00001##

In Chemical Formula 1, R.sub.1 to R.sub.5 are each independently any one selected from the group consisting of H, an alkyl group having 1 to 10 carbon atoms, and an alkoxy group having 1 to 10 carbon atoms, and R may be an aliphatic unsaturated hydrocarbon group having 2 to 10 carbon atoms, or —OR′ (R′ is an aliphatic unsaturated hydrocarbon group having 2 to 10 carbon atoms).

An electrolyte for a rechargeable lithium-ion battery includes a solvent consisting of 10.0 wt. % to 35.0 wt. % carbonate-based solvent and 50.0 wt. % to 80.0 wt. % propionate-based solvent, 1.1M to 1.3M lithium salt, 0.1 wt. % to 12.0 wt. % of a phosphazene-based flame retardant, 1,3,6-hexanetricarbonitrile and succinonitrile together in a range of 0.1 wt. % to 5.0 wt. %, and 1.7 wt. % to 15.0 wt. % additives.

A non-aqueous electrolyte solution for a lithium secondary battery, and a lithium secondary battery including the same are disclosed herein. In some embodiments, the non-aqueous electrolyte solution for a lithium secondary battery includes a lithium salt, an organic solvent, and a compound represented by the following Formula 1, and has an excellent effect of scavenging decomposition products generated from the lithium salt, and thus, may improve overall performance of the battery:

##STR00001## wherein in Formula 1, A is a C1 to C5 alkyl group.

The invention provides an electrolyte solution capable of providing an electrochemical device having low resistance and excellent high-temperature storage characteristics and cycle characteristics. The electrolyte solution contains lithium fluorosulfonate and a solvent containing a compound (1) represented by the following formula (1): CF.sub.2HCOOCH.sub.3.

A purpose of the present invention is to provide a lithium ion secondary battery which has further improved life characteristics. The lithium ion secondary battery of the present invention is characterized by comprising a positive electrode comprising a positive electrode active material that operates at 4.5 V or more with respect to lithium, and an electrolyte solution comprising an electrolyte solvent comprising a fluorinated ether, a cyclic sulfonic acid ester and LiN(FSO.sub.2).sub.2.

According to one embodiment, a method of producing a secondary battery is provided. The method includes preparing a battery architecture including a positive electrode, a negative electrode, and an electrolyte; adjusting a positive electrode potential to a range of 3.4 V to 3.9 V and a negative electrode potential to a range of 1.5 V to 2.0 V based on an oxidation-reduction potential of lithium, thereby providing a potential adjusted state; and holding the battery architecture in the potential adjusted state at a holding temperature of 50° C. to 90° C. The positive electrode includes a lithium-nickel-cobalt-manganese composite oxide. The negative electrode includes a niobium-titanium composite oxide. The electrolyte includes one or more first organic solvent having a viscosity of 1 cP or less.

A battery includes a positive electrode containing sulfur, a negative electrode containing a material for occluding and releasing a lithium ion, and an electrolytic solution. The electrolytic solution contains at least one of a liquid complex and a liquid salt in which a polysulfide is insoluble or almost insoluble, and a solvent in which a polysulfide is soluble. The electrolytic solution has a Li.sub.2S.sub.8 saturation sulfur concentration of 10 mM or more and 400 mM or less.