Abstract: A non-aqueous electrolyte solution for a lithium secondary battery according to the present technology includes: a lithium salt; an organic solvent; and a first additive, and the first additive includes a compound represented by following Chemical formula 1: Herein, R1 is a substituted or unsubstituted unsaturated hydrocarbon group having 2 to 20 carbon atoms, and R2 is one selected from the group consisting of a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms and a substituted or unsubstituted cyclic alkyl group having 3 to 8 carbon atoms.

Abstract: The present invention relates to a composition for a polymer electrolyte which includes a polymerizable oligomer capable of forming an excellent crosslink during a polymerization reaction. Also, the present invention relates to a polymer electrolyte, which may ensure high oxidation stability and ionic conductivity by using the composition for a polymer electrolyte, and a lithium secondary battery including the same.

Abstract: The present invention relates to a composition for a gel polymer electrolyte, which includes a lithium salt, a non-aqueous organic solvent, a polymerization initiator, and an oligomer containing a polycarbonate-based repeating unit, a gel polymer electrolyte in which mechanical strength and ion transfer capability are improved by polymerization of the composition for a gel polymer electrolyte, and a lithium secondary battery in which external impact and stability during high-temperature storage are improved by including the gel polymer electrolyte.

Abstract: A method of activating a secondary battery includes an operation of deriving a reduction reaction voltage according to an electrolyte additive, a pre-charging operation of pre-charging the secondary battery into which an electrolyte containing the electrolyte additive is injected, and a pre-aging operation of wetting an electrode assembly accommodated in the secondary battery with the injected electrolyte and aging the electrode assembly. A charging termination voltage in the pre-charging operation is less than the reduction reaction voltage.

Abstract: The present invention relates to a compound capable of lowering the flammability of a non-aqueous electrolyte when included in the non-aqueous electrolyte and improving the life properties of a battery by forming an electrode-electrolyte interface which is stable at high temperatures and low in resistance, and relates to a compound represented by Formula I descried herein, a non-aqueous electrolyte solution and a lithium secondary battery both including the compound, n, m, Ak, and X are described herein.

Abstract: A non-aqueous electrolyte solution for a lithium secondary battery and a lithium secondary battery including the same are described herein. Specifically, the non-aqueous electrolyte solution for a lithium secondary battery includes a lithium salt, a first solvent including a non-fluorine-based solvent, a second solvent including a fluorine-based carbonate solvent, and a third solvent including a fluorine-based acetate solvent, wherein the fluorine-based carbonate solvent and the fluorine-based acetate solvent are included in a weight ratio of 1:0.5 to 1:1, and a mixed amount of the fluorine-based carbonate solvent and the fluorine-based acetate solvent may be in a range of 3.0 wt % to 30 wt % based on a total weight of the non-aqueous electrolyte solution for a lithium secondary battery.

Abstract: A lithium secondary battery includes a negative electrode, a positive electrode positioned opposite to the negative electrode, a separator disposed between the negative electrode and the positive electrode, and a non-aqueous electrolyte, wherein the negative electrode includes a silicon-based active material, the silicon-based active material comprises a compound represented by SiOx, wherein 0?x<2, the non-aqueous electrolyte includes a lithium salt, an organic solvent, and an additive, the additive includes a first additive and a second additive, the first additive includes a coumarin-based compound represented by Formula 1, and the second additive includes at least one of lithium fluoromalonato(difluoro)borate (LiFMDFB), lithium difluoro(oxalato)borate (LiDFOB), lithium difluorophosphate (LiDFP), or lithium difluorobis-(oxalate)phosphate (LiDFOP): wherein R and n are described herein.

Abstract: The present invention relates to a hole forming device for pierced earrings which comprises a body of an earring including a pin member which has a tapered end part and penetrates an ear and an ornamental member integrally connected to the other end part of the pin member which is exposed on the front side of the ear; a clip for gripping the end part of the pin member behind the ear; and a guide member having a through hole and a projecting part at one end toward the front side of the ear.The present invention provides a hole forming device for pierced earrings whereby various earrings can be replaced and users' various desires can be satisfied even while a hole is being formed.