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EP-4535493-B1 - NON-AQUEOUS ELECTROLYTE SOLUTION FOR LITHIUM SECONDARY BATTERY AND LITHIUM SECONDARY BATTERY INCLUDING THE SAME

EP4535493B1EP 4535493 B1EP4535493 B1EP 4535493B1EP-4535493-B1

Inventors

  • JI, SU HYEON
  • LEE, CHUL HAENG
  • LEE, KYUNG MI
  • LEE, JUNG MIN
  • YEOM, Chul Eun
  • HAN, JUNG GU
  • CHO, YOON GYO

Dates

Publication Date
20260513
Application Date
20230705

Claims (11)

  1. A non-aqueous electrolyte solution for a lithium secondary battery, comprising a lithium salt; an organic solvent; and a compound represented by Formula 1: in Formula 1, L1 is a direct bond or an alkylene group having 1 to 10 carbon atoms, R1 is an alkyl group having 1 to 10 carbon atoms or a nitrile group, L2 is a direct bond, an alkylene group having 1 to 10 carbon atoms, an alkyleneoxy group having 1 to 10 carbon atoms, or a sulfonyl group, R2 is a fluorine-substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a nitrile group, or an isocyanate group, R3 is a fluorine-substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, n is an integer of any one of 0 to 2, and when n is 2, the two R3s are same or different from each other.
  2. The non-aqueous electrolyte solution for a lithium secondary battery of claim 1, wherein R2 in Formula 1 is an alkyl group having 1 to 5 carbon atoms, a fluoroalkyl group having 1 to 5 carbon atoms, or an isocyanate group.
  3. The non-aqueous electrolyte solution for a lithium secondary battery of claim 1, wherein R3 in Formula 1 is a fluorine-substituted alkyl group having 1 to 10 carbon atoms.
  4. The non-aqueous electrolyte solution for a lithium secondary battery of claim 1, wherein the compound represented by Formula 1 is represented by Formula 1-1 or Formula 1-2: in Formulae 1-1 and 1-2, R1 to R3 are as defined in Formula 1.
  5. The non-aqueous electrolyte solution for a lithium secondary battery of claim 1, wherein an amount of the compound represented by Formula 1 is in a range of 0.01 wt% to 15 wt% based on a total weight of the non-aqueous electrolyte solution.
  6. The non-aqueous electrolyte solution for a lithium secondary battery of claim 1, wherein an amount of the compound represented by Formula 1 is in a range of 0.05 wt% to 10 wt% based on a total weight of the non-aqueous electrolyte solution.
  7. The non-aqueous electrolyte solution for a lithium secondary battery of claim 1, further comprising at least one additive selected from the group consisting of vinylene carbonate, vinyl ethylene carbonate, 1,3-propane sultone, ethylene sulfate, lithium tetrafluoroborate, lithium difluoro(oxalato)borate, and lithium difluorophosphate.
  8. The non-aqueous electrolyte solution for a lithium secondary battery of claim 1, wherein the organic solvent comprises a mixture of at least two selected from the group consisting of a cyclic carbonate-based solvent, a linear carbonate-based solvent, and a linear ester-based solvent.
  9. A lithium secondary battery comprising: a positive electrode including a positive electrode active material; a negative electrode including a negative electrode active material; a separator disposed between the positive electrode and the negative electrode; and the non-aqueous electrolyte solution of claim 1.
  10. The lithium secondary battery of claim 9, wherein the positive electrode active material comprises a lithium composite transition metal oxide represented by Formula 2: [Formula 2] Li 1+x (Ni a Co b Mn c M d )O 2 in Formula 2, M is at least one selected from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo, and 1+x, a, b, c, and d are atomic fractions of each independent element, wherein -0.2≤x≤0.2, 0.6≤a<1, 0<b≤0.3, 0<c≤0.3, 0≤d≤0.1, and a+b+c+d=1.
  11. The lithium secondary battery of claim 10, wherein a, b, c, and d in Formula 2 satisfy 0.70≤a<1, 0<b≤0.2, 0<c≤0.2, and 0≤d≤0.1, respectively.

Description

TECHNICAL FIELD This application claims priority from Korean Patent Application Nos. 10-2022-0085281, filed on July 11, 2022, and 10-2023-0086887, filed on July 5, 2023. The present invention relates to a non-aqueous electrolyte solution for a lithium secondary battery and a lithium secondary battery including the same. BACKGROUND ART A lithium secondary battery is generally prepared by a method in which, after an electrode assembly is formed by disposing a separator between a positive electrode, which includes a positive electrode active material formed of a transition metal oxide containing lithium, and a negative electrode including a negative electrode active material capable of storing lithium ions and the electrode assembly is inserted into a battery case, a non-aqueous electrolyte solution that becomes a medium for transferring the lithium ions is injected thereinto and the battery case is then sealed. Since the lithium secondary battery may be miniaturized and has high energy density and working voltage, it is being used in various fields such as mobile devices, electronic products, and electric vehicles. As the field of application of the lithium secondary battery is diversified, physical property conditions required are also gradually increasing, and, particularly, development of a lithium secondary battery, which may be stably operated even under high-temperature conditions and has long life characteristics, is required. In a case in which the lithium secondary battery is operated under high-temperature conditions, PF6- anions may be thermally decomposed from a lithium salt, such as LiPF6, contained in the electrolyte solution to generate a Lewis acid such as PF5, and this reacts with moisture to generate HF. Decomposition products, such as PF5 and HF, may not only destroy a film formed on a surface of the electrode, but also may cause a decomposition reaction of an organic solvent and may react with a decomposition product of the positive electrode active material to dissolve transition metal ions, and the dissolved transition metal ions may be electrodeposited on the negative electrode to destroy a film formed on a surface of the negative electrode. Since performance of the battery is further degraded if the electrolyte decomposition reaction continues on the destroyed film as described above, there is a need to develop a secondary battery capable of maintaining excellent performance even under high-temperature conditions. WO 2011/043403 discloses electrolyte solutions comprising substituted pyrazole additives. DISCLOSURE OF THE INVENTION TECHNICAL PROBLEM An aspect of the present invention provides a non-aqueous electrolyte solution, which may form a stable film on an electrode and may control metal dissolution by including a R2-substituted pyrazolecarboxylic acid-derived compound and accordingly may contribute to improve performance of a lithium secondary battery, and a lithium secondary battery including the same. TECHNICAL SOLUTION According to an aspect of the present invention, there is provided a non-aqueous electrolyte solution for a lithium secondary battery which includes: a lithium salt; an organic solvent; and a compound represented by Formula 1. In Formula 1, L1 is a direct bond or an alkylene group having 1 to 10 carbon atoms,R1 is an alkyl group having 1 to 10 carbon atoms or a nitrile group,L2 is a direct bond, an alkylene group having 1 to 10 carbon atoms, an alkyleneoxy group having 1 to 10 carbon atoms, or a sulfonyl group,R2 is a fluorine-substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a nitrile group, or an isocyanate group,R3 is a fluorine-substituted or unsubstituted alkyl group having 1 to 10 carbon atoms,n is an integer of any one of 0 to 2, and when n is 2, the two R3s are the same or different from each other. According to another aspect of the present invention, there is provided a lithium secondary battery including: a positive electrode including a positive electrode active material; a negative electrode including a negative electrode active material; a separator disposed between the positive electrode and the negative electrode; and the non-aqueous electrolyte solution for a lithium secondary battery. The invention is defined in the appended claims. ADVANTAGEOUS EFFECTS A non-aqueous electrolyte solution according to the present invention may contribute to improve high-temperature performance of a lithium secondary battery by including a compound represented by Formula 1 which has a function of strengthening a positive electrode/negative electrode film and controlling dissolved metal. Particularly, since the compound includes a functional group based on fluorine, sulfur, and nitrogen in its structure, it may contribute to improve stability and safety of the battery through formation of an organic/inorganic composite film. Also, since an interaction with transition metal is possible through nitrogen (N) and COO functional groups which are incl