EP-4293782-B1 - NON-AQUEOUS ELECTROLYTE SOLUTION AND LITHIUM SECONDARY BATTERY INCLUDING THE SAME

Inventors

• OH, JEONG WOO
• CHO, YOON GYO
• LEE, CHUL HAENG

Dates

Publication Date

20260506

Application Date

20220825

Claims (10)

1. A non-aqueous electrolyte solution comprising: a lithium salt; a non-aqueous organic solvent; and a compound represented by Formula 1: wherein, in Formula 1, R 1 is an alkyl group having 1 to 5 carbon atoms which is unsubstituted or substituted with at least one fluorine element or -OR 3 , where R 3 is an alkyl group having 1 to 5 carbon atoms which is unsubstituted or substituted with at least one fluorine element, and R 2 is a heterocycloalkenyl group having 2 to 8 carbon atoms which includes at least one nitrogen atom or -C(O)-R 4 , where R 4 is a heterocycloalkenyl group having 2 to 8 carbon atoms which includes at least one nitrogen atom.
2. The non-aqueous electrolyte solution of claim 1, wherein, in Formula 1, R 1 is an alkyl group having 1 to 3 carbon atoms which is unsubstituted or substituted with at least one fluorine element or -OR 3 , where R 3 is an alkyl group having 1 to 3 carbon atoms which is unsubstituted or substituted with at least one fluorine element, and R 2 is a heterocycloalkenyl group having 2 to 6 carbon atoms which includes at least one nitrogen atom or -C(O)-R 4 , where R 4 is a heterocycloalkenyl group having 2 to 6 carbon atoms which includes at least one nitrogen atom.
3. The non-aqueous electrolyte solution of claim 1, wherein, in Formula 1, R 1 is at least one selected from -CH 3 , -CF 3 , -OCH 3 , and -OCF 3 , and R 2 is at least one selected from
4. The non-aqueous electrolyte solution of claim 1, wherein the compound represented by Formula 1 is at least one of compounds represented by Formulae 1-1 to 1-4:
5. The non-aqueous electrolyte solution of claim 1, wherein the compound represented by Formula 1 is included in an amount of 0.1 wt% to 7.0 wt% based on a total weight of the non-aqueous electrolyte solution.
6. The non-aqueous electrolyte solution of claim 1, wherein the compound represented by Formula 1 is included in an amount of 0.5 wt% to 5.0 wt% based on a total weight of the non-aqueous electrolyte solution.
7. A lithium secondary battery comprising a positive electrode; a negative electrode; a separator disposed between the positive electrode and the negative electrode; and the non-aqueous electrolyte solution of claim 1.
8. The lithium secondary battery of claim 7, wherein the negative electrode comprises a silicon-based active material.
9. The lithium secondary battery of claim 8, wherein the silicon-based active material comprises at least one selected from the group consisting of metallic silicon (Si), silicon oxide SiO x , where 0<x<2, silicon carbide (SiC), and a Si-Y alloy where Y is an element selected from the group consisting of alkali metal, alkaline earth metal, a Group 13 element, a Group 14 element, transition metal, a rare earth element, and a combination thereof, and is not Si.
10. The lithium secondary battery of claim 7, wherein the negative electrode further comprises a carbon-based active material.

Description

TECHNICAL FIELD Cross-reference to Related Applications This application claims priority from Korean Patent Application No. 10-2021-0113470, filed on August 26, 2021. Technical Field The present invention relates to a non-aqueous electrolyte solution having improved high-temperature stability and high-temperature durability and a lithium secondary battery including the same. BACKGROUND ART Demand for high-stability lithium ion secondary batteries is gradually increasing as personal IT devices and computer networks are recently developed with the development of information society and the accompanying dependency of society as a whole on the electrical energy is increased. A lithium ion secondary battery is a battery system with the highest theoretical energy density among secondary battery technologies, wherein it is advantageous in that it may be applied to various devices and may be miniaturized to be applicable to the personal IT devices. The lithium ion secondary battery is composed of a positive electrode that includes a positive electrode active material formed of a transition metal oxide containing lithium, a negative electrode formed of a negative electrode active material, such as a carbon-based material, capable of storing lithium, a non-aqueous electrolyte solution that becomes a medium for transferring lithium ions, and a separator. In the lithium secondary battery, lithium ions from the positive electrode active material, such as a lithium metal oxide, move to the negative electrode active material during initial charge to be intercalated between layers of the negative electrode active material. In this case, since the lithium ion has strong reactivity, an electrolyte solution composition and a material constituting the negative electrode active material react on a surface of the negative electrode active material to form an SEI (Solid Electrolyte Interface) film, a kind of protective film, on the surface of the negative electrode active material. The SEI film prevents destruction of a negative electrode structure due to intercalation of organic solvent molecules having a large molecular weight, which move together with the lithium ions in the electrolyte solution composition, between the layers of the negative electrode active material. Thus, decomposition of the electrolyte solution composition does not occur by preventing a contact between the electrolyte solution composition and the negative electrode active material, and an amount of the lithium ions in the electrolyte solution composition is reversibly maintained to maintain stable charge and discharge. Accordingly, an interest in an additive for forming a stable SEI film on a surface of the negative electrode is increasing. Recently, a silicon-based negative electrode active material, which may achieve high energy density because of its higher theoretical capacity than graphite, has emerged as a component of the negative electrode active material. However, with respect to the silicon-based negative electrode active material, a serious volume change of active material particles occurs due to repeated charge and discharge and, as a result, cracks in the SEI film formed on the surface of the negative electrode occur. Since a new negative electrode surface is continuously exposed to the electrolyte solution due to these cracks, a thick and unstable film may be formed and the film with an unstable structure may reduce stability, particularly, high-temperature stability. Therefore, there is a need to develop a non-aqueous electrolyte solution capable of forming a stable SEI film having high-temperature durability instead of an SEI film formed from a conventional carbonate-based organic solvent. KR 2019 0062158 describes a functional electrolyte for a lithium ion battery and a lithium ion battery including the same. US 2021/234199 describes a non-aqueous liquid electrolyte composition suitable for secondary battery cells, especially lithium-ion secondary battery cells. Such electrolyte composition comprises a) at least one non-fluorinated cyclic carbonate and at least one fluorinated cyclic carbonate, b) at least one fluorinated acyclic carboxylic acid ester, c) at least one electrolyte salt, d) at least one lithium borate compound, e) at least one cyclic sulfur compound, and f) optionally at least one cyclic carboxylic acid anhydride, all components being present in specific proportions. KR 102 283 805 describes an electrolyte additive that can be added to an electrolyte for a lithium secondary battery, a method for preparing the same, an electrolyte and a secondary battery including the same. JP 2006 164860 describes a lithium secondary battery suitable for an electric hybrid vehicle or the like. KR 2020 0105227 describes an electrolyte for a lithium secondary battery with high-temperature characteristics and a lithium secondary battery including the same. DISCLOSURE OF THE INVENTION TECHNICAL PROBLEM An aspect of the present invention provide