Electrolyte for rechargeable lithium battery and rechargeable lithium battery including the same

Abstract

To provide an electrolyte for a rechargeable lithium battery capable of improving high-temperature characteristics of the rechargeable lithium battery, and a rechargeable lithium battery having excellent high-temperature characteristics in a high-voltage environment.SOLUTION: An electrolyte for a rechargeable lithium battery includes a lithium salt, a non-aqueous organic solvent, and an additive. The non-aqueous organic solvent includes a first compound represented by the upper chemical formula. The additive includes a compound represented by the lower chemical formula.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an electrolyte solution for a lithium secondary battery and a lithium secondary battery containing the same. [Background technology]

[0002] In recent years, the rapid spread of battery-powered electronic devices such as mobile phones, laptops, and electric vehicles has led to a rapid increase in demand for high-energy-density, high-capacity secondary batteries, which has led to active research and development efforts to improve the performance of lithium secondary batteries.

[0003] A lithium secondary battery is a battery that includes a cathode and an anode, each containing an active material capable of intercalating and deintercalating lithium ions, and an electrolyte. Electrical energy is generated through oxidation and reduction reactions that occur when lithium ions are intercalated and deintercalated at the cathode and anode. Summary of the Invention [Problem to be solved by the invention]

[0004] One aspect is to provide an electrolyte for a lithium secondary battery that improves the high-temperature characteristics of the lithium secondary battery.

[0005] Another aspect is to provide a lithium secondary battery that contains the above-mentioned electrolyte solution and has excellent high-temperature characteristics in a high-voltage environment. [Means for solving the problem]

[0006] An electrolyte solution for a lithium secondary battery according to one embodiment of the present invention includes a lithium salt, a non-aqueous organic solvent, and an additive.

[0007] The non-aqueous organic solvent contains a compound represented by the following Chemical Formula 1:

[0008] [C1] [ka]

[0009] In Chemical Formula 1, R 1A and R 1B are each independently hydrogen, halogen, a substituted or unsubstituted C1 to C10 alkyl group, or a substituted or unsubstituted C3 to C10 cycloalkyl group.

[0010] The additive includes a compound represented by the following chemical formula 2:

[0011] [C2] [ka]

[0012] In Chemical Formula 2, L 2A and L 2B are each independently a single bond, a substituted or unsubstituted C1 to C5 alkylene group, a substituted or unsubstituted C2 to C5 alkenylene group, a substituted or unsubstituted C2 to C5 alkynylene group, or a substituted or unsubstituted C6 to C20 arylene group.

[0013] A and B are each independently a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C6 to C20 aryl group, or a substituted or unsubstituted C2 to C20 heteroaryl group.

[0014] At least one of A and B is a group represented by the following chemical formula A.

[0015] [Chemical A] [ka]

[0016] In chemical formula A, R 2A and R 2Bare each independently hydrogen, halogen, a substituted or unsubstituted C1 to C10 alkyl group, or a substituted or unsubstituted C3 to C10 cycloalkyl group.

[0017] Another aspect provides a lithium secondary battery including a positive electrode containing a positive electrode active material, a negative electrode containing a negative electrode active material, and the above-described electrolyte solution for lithium secondary batteries. [Effects of the Invention]

[0018] A lithium secondary battery including an electrolyte solution according to one embodiment provides a lithium secondary battery with excellent high-temperature characteristics in a high-voltage environment. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a simplified conceptual diagram of a lithium secondary battery according to an embodiment of the present invention; [Figure 2] 1 is a cross-sectional view schematically illustrating a lithium secondary battery according to one embodiment. [Figure 3] 1 is a cross-sectional view schematically illustrating a lithium secondary battery according to one embodiment. [Figure 4] 1 is a cross-sectional view schematically illustrating a lithium secondary battery according to one embodiment. [Figure 5] 1 is a cross-sectional view schematically illustrating a lithium secondary battery according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0020] In order to fully understand the configuration and effects of the present invention, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, and can be embodied in various forms and can be modified in various ways. However, the description of the present embodiments is provided to ensure complete disclosure of the present invention and to fully convey the scope of the invention to those skilled in the art.

[0021] In this specification, when a component is referred to as being on top of another component, it means that it may be formed directly on the other component, or that a third component may be interposed between them. Also, in the drawings, the thickness of the components may be exaggerated for the purpose of effectively explaining the technical content. Throughout the specification, parts designated with the same reference numerals refer to the same components.

[0022] Unless otherwise stated herein, the singular can also include the plural. Additionally, unless otherwise stated, "A or B" can mean "including A but not B," "including B but not A," and "including A and B." As used herein, "comprises" and / or "comprising" do not exclude the presence or addition of one or more other elements to the recited element.

[0023] As used herein, "combinations thereof" can mean mixtures, laminates, composites, copolymers, alloys, blends, reaction products, and the like of compositions.

[0024] Unless otherwise defined herein, particle size may refer to the average particle size. Furthermore, particle size refers to the average particle size (D50), which refers to the diameter of particles with a cumulative volume of 50 vol% in a particle size distribution. The average particle size (D50) may be measured using a method well known to those skilled in the art, such as a particle size analyzer, or a transmission electron microscope or scanning electron microscope. Alternatively, the average particle size (D50) may be measured using a measuring device using dynamic light scattering, and data analysis may be performed to count the number of particles in each particle size range, followed by calculation. Alternatively, the average particle size (D50) may be measured using a laser diffraction method. When measuring by the laser diffraction method, more specifically, the particles to be measured may be dispersed in a dispersion medium, then introduced into a commercially available laser diffraction particle size measuring device (e.g., MT 3000 manufactured by Microtrac), and irradiated with ultrasonic waves of approximately 28 kHz at an output of 60 W, after which the average particle size (D50) based on 50% of the particle size distribution in the measuring device may be calculated.

[0025] As used herein, unless otherwise defined, the term "substituted" means that at least one hydrogen atom in a substituent or compound is replaced with deuterium, a halogen group, a hydroxyl group, an amino group, a C1 to C30 amine group, a nitro group, a C1 to C40 silyl group, a C1 to C30 alkyl group, a C1 to C10 alkylsilyl group, a C6 to C30 arylsilyl group, a C3 to C30 cycloalkyl group, a C3 to C30 heterocycloalkyl group, a C6 to C30 aryl group, a C2 to C30 heteroaryl group, a C1 to C20 alkoxy group, a C1 to C10 fluoroalkyl group, a cyano group, or a combination thereof.

[0026] Specifically, "substituted" may mean that at least one hydrogen atom in a substituent or compound is replaced with deuterium, a halogen group, a C1 to C30 alkyl group, a C1 to C10 alkylsilyl group, a C6 to C30 arylsilyl group, a C3 to C30 cycloalkyl group, a C3 to C30 heterocycloalkyl group, a C6 to C30 aryl group, a C2 to C30 heteroaryl group, a C1 to C10 fluoroalkyl group, or a cyano group. For example, "substituted" may mean that at least one hydrogen atom in a substituent or compound is replaced with deuterium, a halogen group, a C1 to C20 alkyl group, a C6 to C30 aryl group, a C1 to C10 fluoroalkyl group, or a cyano group. Alternatively, "substituted" may mean that at least one hydrogen atom in a substituent or compound is replaced with deuterium, a halogen group, a C1 to C5 alkyl group, a C6 to C18 aryl group, a C1 to C5 fluoroalkyl group, or a cyano group. As an example, "substituted" may mean that at least one hydrogen in a substituent or compound is replaced with deuterium, a cyano group, a halogen group, a methyl group, an ethyl group, a propyl group, a butyl group, a phenyl group, a biphenyl group, a terphenyl group, a trifluoromethyl group, or a naphthyl group.

[0027] 1 is a schematic diagram illustrating a lithium secondary battery according to an embodiment of the present invention. Referring to FIG. 1, the lithium secondary battery may include a positive electrode 10, a negative electrode 20, a separator 30, and an electrolyte solution ELL.

[0028] The positive electrode 10 and the negative electrode 20 may be separated from each other by a separator 30. The separator 30 may be disposed between the positive electrode 10 and the negative electrode 20. The positive electrode 10, the negative electrode 20, and the separator 30 may be in contact with an electrolyte solution ELL. The positive electrode 10, the negative electrode 20, and the separator 30 may be impregnated in the electrolyte solution ELL.

[0029] The electrolyte ELL may be a medium for transferring lithium ions between the positive electrode 10 and the negative electrode 20. In the electrolyte ELL, the lithium ions may pass through the separator 30 and move toward the positive electrode 10 or the negative electrode 20.

[0030] positive electrode 10 The lithium secondary battery positive electrode 10 may include a current collector COL1 and a positive electrode active material layer AML1 formed on the current collector COL1. The positive electrode active material layer AML1 includes a positive electrode active material and may further include a binder and / or a conductive material.

[0031] As an example, cathode 10 may further include an additive that can act as a sacrificial cathode.

[0032] The content of the positive electrode active material in the positive electrode active material layer AML1 may be 90 wt% to 99.5 wt% relative to 100 wt% of the positive electrode active material layer AML1, and the contents of the binder and conductive material may be 0.5 wt% to 5 wt% each relative to 100 wt% of the positive electrode active material layer AML1.

[0033] The binder serves to firmly bind the positive electrode active material particles to each other and to firmly attach the positive electrode active material to the current collector COL1. Representative examples of binders include, but are not limited to, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, (meth)acrylic styrene-butadiene rubber, epoxy resin, (meth)acrylic resin, polyester resin, nylon, etc.

[0034] The conductive material is used to impart conductivity to the electrode, and may be any material that does not cause a chemical change in the constructed battery and is electronically conductive. Examples of the conductive material include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, carbon fiber, carbon nanofiber, and carbon nanotube; metal-based materials in the form of metal powder or metal fiber containing copper, nickel, aluminum, silver, etc.; conductive polymers such as polyphenylene derivatives; and mixtures thereof.

[0035] The current collector COL1 may be made of Al, but is not limited to this.

[0036] positive electrode active material The positive electrode active material in the positive electrode active material layer AML1 may be a compound capable of reversibly inserting and extracting lithium (lithiated intercalation compound). Specifically, one or more composite oxides of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof may be used.

[0037] The composite oxide may be a lithium transition metal composite oxide, but specific examples include lithium nickel-based oxide, lithium cobalt-based oxide, lithium manganese-based oxide, lithium iron phosphate-based oxide, cobalt-free nickel-manganese-based oxide, or a combination thereof.

[0038] For example, a compound represented by any one of the following chemical formulas may be used: Li a A 1-b X b O 2-c D c (0.90≦a≦1.8, 0≦b≦0.5, 0≦c≦0.05), Li a Mn 2-b X b O 4-c D c (0.90≦a≦1.8, 0≦b≦0.5, 0≦c≦0.05), Li a Ni 1-b-c Cob X c O 2-α D α (0.90≦a≦1.8, 0≦b≦0.5, 0≦c≦0.5, 0<α<2), Li a Ni 1-b-c Mn b X c O 2-α D α (0.90≦a≦1.8, 0≦b≦0.5, 0≦c≦0.5,0<α<2), Li a Ni b Co c L 1 d G e O2 (0.90≦a≦1.8, 0≦b≦0.9, 0≦c≦0.5, 0≦d≦0.5, 0≦e≦0.1), Li a NiG b O2 (0.90≦a≦1.8, 0.001≦b≦0.1), Li a CoG b O2 (0.90≦a≦1.8, 0.001≦b≦0.1), Li a Mn 1-b G b O2 (0.90≦a≦1.8, 0.001≦b≦0.1), Li a Mn2G b O4 (0.90≦a≦1.8, 0.001≦b≦0.1), Li a Mn 1-g G g PO4(0.90≦a≦1.8, 0≦g≦0.5), Li (3-f) Fe2(PO4)3(0≦f≦2), Li a FePO4(0.90≦a≦1.8).

[0039] In the chemical formula, A is Ni, Co, Mn, or a combination thereof; X is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; D is O, F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; and L 1 is Mn, Al, or a combination thereof.

[0040] For example, the positive electrode active material may be a high-nickel positive electrode active material having a nickel content of 80 mol% or more, 85 mol% or more, 90 mol% or more, 91 mol% or more, or 94 mol% or more and 99 mol% or less relative to 100 mol% of metals excluding lithium from the lithium transition metal composite oxide. Because the high-nickel positive electrode active material can achieve high capacity, it may be applied to high-capacity, high-density lithium secondary batteries.

[0041] negative electrode 20 The lithium secondary battery negative electrode 20 may include a current collector COL2 and a negative electrode active material layer AML2 formed on the current collector COL2. The negative electrode active material layer AML2 includes a negative electrode active material (e.g., particulate) and may further include a binder and / or a conductive material (e.g., an electron conductor).

[0042] For example, the negative electrode active material layer AML2 may contain 90 wt% to 99 wt% of negative electrode active material, 0.5 wt% to 5 wt% of binder, and 0 wt% to 5 wt% of conductive material, where the total weight of the negative electrode active material layer is 100 wt%.

[0043] The binder serves to firmly bind the negative electrode active material particles to each other and to firmly bind the negative electrode active material to the current collector COL2. The binder may be a non-aqueous (e.g., non-water-soluble) binder, an aqueous (e.g., water-soluble) binder, a dry binder, or any suitable combination thereof.

[0044] Non-aqueous binders include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamideimide, polyimide, or (e.g., any suitable) combination thereof.

[0045] The water-based binder may be selected from styrene-butadiene rubber, (meth)acrylate styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluororubber, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyether resin, (meth)acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, and combinations thereof (e.g., any suitable).

[0046] When an aqueous binder is used as the negative electrode binder, it may further contain a cellulose-based compound to impart viscosity. The cellulose-based compound may be a mixture of one or more of carboxymethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, or alkali metal salts thereof. The alkali metal may be Na, K, or Li.

[0047] The dry binder may be a fiberizable polymeric material such as polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, ethylene oxide, or combinations thereof.

[0048] The conductive material (e.g., an electrically conductive or electronically conductive material) is used to provide electrical conductivity to the electrode. Any material may be used as long as it does not cause a chemical change in the constructed battery and is electronically conductive. Specific examples include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, carbon fiber, carbon nanofiber, and carbon nanotube; metal-based materials in the form of metal powder or metal fiber, including copper, nickel, aluminum, and silver; conductive polymers such as polyphenylene derivatives; and mixtures thereof.

[0049] The current collector COL2 may be selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and combinations thereof.

[0050] negative electrode active material The negative electrode active material in the negative electrode active material layer AML2 includes a material capable of reversibly inserting / extracting lithium ions, lithium metal, a lithium metal alloy, a material capable of being doped with or de-doped from lithium, or a transition metal oxide.

[0051] The material capable of reversibly inserting / extracting lithium ions may be a carbon-based negative electrode active material, such as crystalline carbon, amorphous carbon, or a combination thereof. Examples of crystalline carbon include graphite, such as amorphous, plate-like, flake-like, spherical, or fibrous natural or artificial graphite. Examples of amorphous carbon include soft or hard carbon, mesophase pitch carbide, and calcined coke.

[0052] As the alloy of lithium metal, an alloy of lithium and a metal selected from sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), francium (Fr), beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), silicon (Si), antimony (Sb), lead (Pb), indium (In), zinc (Zn), barium (Ba), radium (Ra), germanium (Ge), aluminum (Al), and tin (Sn) may be used.

[0053] As the substance capable of being doped or undoped with lithium, a Si-based negative electrode active material or a Sn-based negative electrode active material may be used. The Si-based negative electrode active material may be silicon, a silicon-carbon composite, SiOx (0 < x ≦ 2), a Si-Q alloy (Q is selected from alkali metals, alkaline earth metals, group 13 elements, group 14 elements (excluding Si), group 15 elements, group 16 elements, transition metals, rare earth elements, and combinations thereof), or a combination of these. The Sn-based negative electrode active material may be Sn, SnO k (0 < k ≦ 2)SnO2, a Sn-based alloy, or a combination of these.

[0054] The silicon-carbon composite may be a composite of silicon and amorphous carbon (for example, particulate). According to one aspect, the silicon-carbon composite may be in a form in which silicon particles and the surface of the silicon particles are coated with amorphous carbon. For example, it may include secondary particles (cores) formed by combining primary silicon particles and an amorphous carbon coating layer (shell) located on the surface of the secondary particles. Amorphous carbon may also be located between the primary silicon particles, and for example, the primary silicon particles may be coated with amorphous carbon. The secondary particles may be dispersed and present in an amorphous carbon matrix.

[0055] The silicon-carbon composite may further include crystalline carbon. For example, the silicon-carbon composite may include a core containing crystalline carbon and silicon particles and an amorphous carbon coating layer located on the surface of the core.

[0056] The Si-based negative electrode active material or the Sn-based negative electrode active material may be used in mixture with a carbon-based negative electrode active material.

[0057] Separator 30 Depending on the type of lithium secondary battery, a separator 30 may be present between the positive electrode 10 and the negative electrode 20. Such separator 30 may be made of polyethylene, polypropylene, polyvinylidene fluoride, or a multilayer film of two or more layers thereof, but it goes without saying that a mixed multilayer film such as a polyethylene / polypropylene two-layer separator, a polyethylene / polypropylene / polyethylene three-layer separator, or a polypropylene / polyethylene / polypropylene three-layer separator may also be used.

[0058] Separator 30 may include a porous substrate and a coating layer comprising an organic material, an inorganic material, or a combination thereof located on one or both sides of the porous substrate.

[0059] The porous substrate may be a polymer membrane made of any one polymer selected from polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyacetal, polyamide, polyimide, polycarbonate, polyether ketone, polyaryl ether ketone, polyetherimide, polyamide imide, polybenzimidazole, polyethersulfone, polyphenylene oxide, cyclic olefin copolymers, polyphenylene sulfide, polyethylene naphthalate, glass fiber, Teflon, and polytetrafluoroethylene, or a copolymer or mixture of two or more of these.

[0060] The organic material may include a polyvinylidene fluoride polymer or a (meth)acrylic polymer.

[0061] The inorganic material may include, but is not limited to, inorganic particles selected from Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, boehmite, and combinations thereof.

[0062] The organic material and the inorganic material may be mixed in one coating layer, or may be stacked in a form in which a coating layer containing an organic material and a coating layer containing an inorganic material are laminated.

[0063] Electrolyte ELL The electrolyte ELL for lithium secondary batteries contains a non-aqueous organic solvent, a lithium salt, and an electrolyte additive.

[0064] The non-aqueous organic solvent according to one embodiment will be described below.

[0065] The non-aqueous organic solvent serves as a medium through which ions involved in the electrochemical reaction of the battery can move.

[0066] The non-aqueous organic solvent may be an ester-based, carbonate-based, ether-based, ketone-based, or alcohol-based solvent, a non-quantum solvent, or a combination thereof.

[0067] The non-aqueous organic solvent may include an ester-based solvent and a carbonate-based solvent.

[0068] The ester-based solvent and the carbonate-based solvent may be mixed in a volume ratio of 1:1 to 9:1. Specifically, the ester-based solvent and the carbonate-based solvent may be mixed in a volume ratio of 1:1 to 6:1, 1:1 to 4:1, or 2:1 to 4:1.

[0069] The ester-based solvent according to one embodiment of the present invention may include a compound represented by the following Chemical Formula 1:

[0070] [C1] [ka]

[0071] In Chemical Formula 1, R 1A and R 1Bmay each independently be hydrogen, halogen, a substituted or unsubstituted C1 to C10 alkyl group, or a substituted or unsubstituted C3 to C10 cycloalkyl group.

[0072] In one embodiment, R 1A may be a substituted or unsubstituted C3 to C10 alkyl group.

[0073] In one embodiment, R 1A may be a substituted or unsubstituted C3 alkyl group.

[0074] In one embodiment, R 1A may be an unsubstituted C3 alkyl group.

[0075] In one embodiment, R 1B may be a substituted or unsubstituted C1 to C2 alkyl group.

[0076] In one embodiment, R 1B may be a substituted or unsubstituted C2 alkyl group.

[0077] In one embodiment, R 1B may be an unsubstituted C2 alkyl group.

[0078] The compound represented by Chemical Formula 1 may be included in an amount of 50 vol% to 95 vol% based on a total 100 vol% of the electrolyte solution for a lithium secondary battery. Specifically, the compound may be included in an amount of 60 vol% to 90 vol% or 70 vol% to 80 vol% based on a total 100 vol% of the electrolyte solution for a lithium secondary battery. When the content range is within the above range, a stable coating can be formed on the surface of the electrode even in high temperature and high voltage environments, and the coating formed on the surface of the electrode with an appropriate thickness prevents an increase in resistance in high temperature and high voltage environments, thereby realizing a lithium secondary battery with improved life and output characteristics.

[0079] As the ester-based solvent according to one embodiment of the present invention, methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate, ethyl butyrate (EB), propyl butyrate, decanolide, mevalonolactone, valerolactone, caprolactone, and the like may be used.

[0080] According to an embodiment of the present invention, the carbonate-based solvent may be dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl pyrrolyl carbonate (MPC), ethyl propyl carbonate (EPC), methyl ethyl carbonate (MEC), ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), or the like.

[0081] The carbonate-based solvent according to one embodiment of the present invention may include ethylene carbonate (EC) and propylene carbonate (PC).

[0082] The ethylene carbonate (EC) and propylene carbonate (PC) may be mixed in a volume ratio of 1:1 to 1:9. Specifically, the ethylene carbonate (EC) and propylene carbonate (PC) may be mixed in a volume ratio of 1:1 to 1:5, 1:1 to 1:3, or 1:1 to 1:1.5.

[0083] Examples of ether solvents that can be used include dibutyl ether, tetraglyme, diglyme, dimethoxyethane, 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, and tetrahydrofuran. Examples of ketone solvents that can be used include cyclohexanone. Examples of alcohol solvents that can be used include ethyl alcohol and isopropyl alcohol. Examples of non-quantum solvents that can be used include nitriles such as R-CN (where R is a linear, branched, or cyclic hydrocarbon group having 2 to 20 carbon atoms, which may contain a double bond, an aromatic ring, or an ether group), amides such as dimethylformamide, dioxolanes such as 1,3-dioxolane and 1,4-dioxolane, and sulfolanes.

[0084] The non-aqueous organic solvents may be used alone or in combination of two or more.

[0085] When a carbonate-based solvent is used, a cyclic carbonate and a chain carbonate may be mixed and used, and the cyclic carbonate and the chain cyclic carbonate may be mixed in a volume ratio of 1:1 to 1:9.

[0086] Lithium salts are substances dissolved in organic solvents and act as a source of lithium ions in the battery, enabling basic lithium secondary battery operation and facilitating the movement of lithium ions between the positive and negative electrodes. Representative examples of lithium salts include LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiAlO2, LiAlCl4, LiPO2F2, LiCl, LiI, LiN(SO3C2F5)2, Li(FSO2)2N (lithium bis(fluorosulfonyl)imide (LiFSI), LiC4F9SO3, LiN(C x F 2x+1 SO2)(C y F 2y+1 SO2) (x and y are positive numbers from 1 to 20), lithium trifluoromethanesulfonate, lithium tetrafluoroethanesulfonate, lithium difluorobis(oxalato)phosphate (LiDFOB), and lithium bis(oxalato)borate (LiBOB).

[0087] An electrolyte additive according to one embodiment will be described below.

[0088] The additive according to one embodiment of the present invention may include a compound represented by the following Chemical Formula 2:

[0089] [C2] [ka]

[0090] In Chemical Formula 2, L 2A and L 2BEach of L may independently be a single bond, a substituted or unsubstituted C1 to C5 alkylene group, a substituted or unsubstituted C2 to C5 alkenylene group, a substituted or unsubstituted C2 to C5 alkynylene group, or a substituted or unsubstituted C6 to C20 arylene group. 2A is a single bond, A may be directly bonded to S via a single bond. 2B is a single bond, then B may be directly bonded to S by a single bond.

[0091] In Chemical Formula 2, A and B may each independently be a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C6 to C20 aryl group, or a substituted or unsubstituted C2 to C20 heteroaryl group.

[0092] In Chemical Formula 2, at least one of A and B may be a group represented by the following Chemical Formula A. For example, at least one of A and B may be a group represented by the following Chemical Formula A, and the other of A and B may be a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C6 to C20 aryl group, or a substituted or unsubstituted C2 to C20 heteroaryl group. In another embodiment, both A and B may be groups represented by the following Chemical Formula A.

[0093] [Chemical A] [ka]

[0094] In chemical formula A, R 2A and R 2B may each independently be hydrogen, halogen, a substituted or unsubstituted C1 to C10 alkyl group, or a substituted or unsubstituted C3 to C10 cycloalkyl group. * represents L shown in Chemical Formula 2. 2A or L 2B It may be at the bonding position with

[0095] In lithium secondary batteries, the non-aqueous electrolyte is decomposed during initial charging and discharging, forming a film with passivation ability on the surfaces of the positive and negative electrodes, improving high-temperature storage characteristics. However, the film is formed by HF generated by the thermal decomposition of lithium salts (such as LiPF6) widely used in lithium-ion batteries. - and PF5 - The positive electrode may be deteriorated by acids such as PF5. Such acid attack causes the elution of transition metal elements at the positive electrode, which changes the surface structure, increasing the surface resistance of the electrode. The theoretical capacity decreases due to the loss of the metal elements that play a central role in redox, which can lead to a decrease in the actual capacity. Furthermore, the eluted transition metal ions are not only electrodeposited on the negative electrode, which reacts in a strong reduction potential range, consuming the battery, but also destroying the coating during electrodeposition, exposing the negative electrode surface, which triggers further decomposition of the electrolyte. As a result, the resistance of the negative electrode increases, increasing the irreversible capacity and resulting in a continuous decrease in the cell capacity. In the present invention, the triazole group and sulfone group of the additive represented by the above-mentioned chemical formula 2 provide unshared electron pairs, thereby forming PF5. - By capturing the ions and stabilizing the LiPF6 salt, the acid caused by the decomposition of the lithium salt can be removed. For example, the compound represented by formula 2 contains both a triazole group and a sulfone group. These groups are also found in PF5 ― This can act to capture and stabilize the LiPF salt, thereby helping to remove the acid produced during the decomposition of the lithium salt.

[0096] The sulfonic acid group contained in Chemical Formula 2 forms a coating on the surface of the positive electrode to inhibit decomposition of the positive electrode active material, thereby inhibiting gas generation and elution of transition metals due to decomposition of the positive electrode active material.

[0097] In addition, the additive represented by Chemical Formula 2 can strengthen the solid electrolyte interfase (SEI) film on the surface of the negative electrode while preventing deterioration of the SEI film and elution of transition metals at the positive electrode during high-temperature storage.

[0098] As an example, L1 and L 2 At least one of may be a substituted or unsubstituted C1 to C5 alkylene group.

[0099] As an example, L 1 and L 2 may each independently be a substituted or unsubstituted C1 to C5 alkylene group.

[0100] As an example, L 1 and L 2 At least one of may be a substituted or unsubstituted C2 to C5 alkylene group.

[0101] As an example, L 1 and L 2 may each independently be a substituted or unsubstituted C2 to C5 alkylene group.

[0102] As an example, Chemical Formula 2 may be represented by Chemical Formula 2-1 below.

[0103] [ka]

[0104] In Chemical Formula 2-1, L 1 and L 2 may each independently be a substituted or unsubstituted C2 to C5 alkylene group.

[0105] In Chemical Formula 2-1, R 21A , R 21B , R 21C , and R 21D may each independently be hydrogen, halogen, a substituted or unsubstituted C1 to C10 alkyl group, or a substituted or unsubstituted C3 to C10 cycloalkyl group.

[0106] In one embodiment, the compound represented by Chemical Formula 2 may be selected from the compounds described in Group 1 below.

[0107] [Group 1] [ka] [ka]

[0108] The compound represented by Chemical Formula 2 may be included in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the total electrolyte solution for lithium secondary batteries.

[0109] As a specific example, the compound represented by Chemical Formula 2 may be included in an amount of 0.5 to 10 parts by weight, 1 to 10 parts by weight, or 1 to 5 parts by weight, based on 100 parts by weight of the total electrolyte solution for a lithium secondary battery. When the content range is as described above, an increase in resistance at high temperatures can be prevented, and a lithium secondary battery with improved life and output characteristics can be realized.

[0110] The electrolyte for lithium secondary batteries may further contain at least one other additive selected from the group consisting of vinylene carbonate (VC), fluoroethylene carbonate (FEC), difluoroethylene carbonate, chloroethylene carbonate, dichloroethylene carbonate, bromoethylene carbonate, dibromoethylene carbonate, nitroethylene carbonate, cyanoethylene carbonate, vinylethylene carbonate (VEC), adiponitrile (AN), succinic acid nitrile (SN), 1,3,6-hexanetricyanide (HTCN), propene sultone (PST), propane sultone (PS), lithium tetrafluoroborate (LiBF), lithium difluorophosphate (LiPOF), and 2-fluorobiphenyl (2-FBP).

[0111] By further including the other additives mentioned above, the life span can be further improved or gas generated at the positive and negative electrodes during high temperature storage can be effectively controlled.

[0112] The other additives may be contained in an amount of 0.2 to 20 parts by weight, more specifically 0.2 to 15 parts by weight, for example 0.2 to 10 parts by weight, based on 100 parts by weight of the total electrolyte solution for lithium secondary batteries.

[0113] If the content of other additives is as described above, it can minimize the increase in film resistance and contribute to improving battery performance.

[0114] The electrolyte for a lithium secondary battery according to the present invention contains both the compound represented by Chemical Formula 1 and the compound represented by Chemical Formula 2, thereby preventing damage to the SEI film in a high-voltage environment and improving high-temperature storage characteristics.

[0115] Lithium secondary battery Lithium secondary batteries may be classified into cylindrical, prismatic, pouch, and coin types depending on their shape. FIGS. 2 to 5 are schematic diagrams showing lithium secondary batteries according to one embodiment, with FIG. 2 illustrating a cylindrical battery, FIG. 3 illustrating a prismatic battery, and FIGS. 4 and 5 illustrating pouch battery types. Referring to FIGS. 2 and 4, a lithium secondary battery 100 may include an electrode assembly 40 having a separator 30 interposed between a positive electrode 10 and a negative electrode 20, and a housing 50 in which the electrode assembly 40 is embedded. The positive electrode 10, the negative electrode 20, and the separator 30 may be impregnated with an electrolyte (not shown). The lithium secondary battery 100 may include a sealing member 60 that seals the housing 50, as shown in FIG. 2. Also, in FIG. 3, the lithium secondary battery 100 may include a positive electrode lead tab 11, a positive electrode terminal 12, a negative electrode lead tab 21, and a negative electrode terminal 22. As shown in FIGS. 4 and 5, the lithium secondary battery 100 may include electrode tabs 70, i.e., a positive electrode tab 71 and a negative electrode tab 72, which serve as electrical paths for conducting the current generated in the positive electrode assembly 40 to the outside.

[0116] The lithium secondary battery according to an embodiment of the present invention may be applied to automobiles, mobile phones, and / or various types of electrical devices, but the present invention is not limited thereto.

[0117] Examples and comparative examples of the present invention will be described below, but the following examples are merely examples of the present invention and are not intended to limit the scope of the present invention. [Example]

[0118] Examples and Comparative Examples An electrolyte and a lithium secondary battery were manufactured as follows.

[0119] Example 1 (1) Electrolyte production An electrolyte solution was prepared by dissolving 1.3 M LiPF6 in a non-aqueous organic solvent containing ethylene carbonate (EC), propylene carbonate (PC), and ethyl butyrate (EB) in a volume ratio of 10:15:75, and adding additives.

[0120] As the additive, a compound (first compound) represented by the following chemical formula 2-1-1 was mixed in an amount of 1 wt % based on 100 wt % of the total electrolyte solution.

[0121] [Case 2-1-1] [ka]

[0122] 2) Manufacture of lithium secondary batteries LiCoO2 as a positive electrode active material, polyvinylidene fluoride as a binder, and acetylene black as a conductive material were mixed in a weight ratio of 96:3:1, and dispersed in N-methylpyrrolidone to prepare a positive electrode active material slurry.

[0123] The positive electrode active material slurry was coated on an Al foil having a thickness of 15 μm, dried at 100° C., and then pressed to prepare a positive electrode.

[0124] Artificial graphite was used as the negative electrode active material, and the negative electrode active material was mixed with styrene-butadiene rubber binder and carboxymethyl cellulose in a weight ratio of 98:1:1, respectively, and dispersed in distilled water to prepare a negative electrode active material slurry.

[0125] The negative electrode active material slurry was coated on a Cu foil with a thickness of 10 μm, dried at 100° C., and then rolled to prepare a negative electrode.

[0126] The positive and negative electrodes were assembled with a 10 μm thick polyethylene separator to prepare an electrode assembly, and an electrolyte was injected to prepare a lithium secondary battery.

[0127] Example 2 An electrolyte solution and a lithium secondary battery were manufactured in the same manner as in Example 1, except that an additive was added in an amount of 3 wt % based on 100 wt % of the first compound electrolyte solution when the electrolyte solution was manufactured.

[0128] Example 3 An electrolyte solution and a lithium secondary battery were manufactured in the same manner as in Example 1, except that an additive was added in an amount of 5 wt% based on 100 wt% of the first compound electrolyte solution when the electrolyte solution was manufactured.

[0129] Example 4 An electrolyte solution and a lithium secondary battery were manufactured in the same manner as in Example 2, except that a non-aqueous organic solvent in which ethylene carbonate (EC), propylene carbonate (PC), and ethyl butyrate (EB) were mixed in a volume ratio of 10:20:70 was used to prepare the electrolyte solution.

[0130] Example 5 An electrolyte solution and a lithium secondary battery were manufactured in the same manner as in Example 2, except that a non-aqueous organic solvent in which ethylene carbonate (EC), propylene carbonate (PC), and ethyl butyrate (EB) were mixed in a volume ratio of 10:10:80 was used to prepare the electrolyte solution.

[0131] Example 6 An electrolyte solution and a lithium secondary battery were manufactured in the same manner as in Example 1, except that a non-aqueous organic solvent in which ethylene carbonate (EC), propylene carbonate (PC), and propyl propionate (PP) were mixed in a volume ratio of 10:15:75 was used to prepare the electrolyte solution.

[0132] Example 7 An electrolyte solution and a lithium secondary battery were manufactured in the same manner as in Example 1, except that a non-aqueous organic solvent in which ethylene carbonate (EC), propylene carbonate (PC), and methyl propionate (MP) were mixed in a volume ratio of 10:15:75 was used to prepare the electrolyte solution.

[0133] Example 8 An electrolyte solution and a lithium secondary battery were manufactured in the same manner as in Example 1, except that a non-aqueous organic solvent in which ethylene carbonate (EC), propylene carbonate (PC), and ethyl propionate (EP) were mixed in a volume ratio of 10:15:75 was used to prepare the electrolyte solution.

[0134] Comparative Example 1 An electrolyte solution and a lithium secondary battery were prepared in the same manner as in Example 1, except that no additives were added when preparing the electrolyte solution.

[0135] Comparative Example 2 An electrolyte and a lithium secondary battery were prepared in the same manner as in Example 1, except that a compound (second compound) represented by the following Chemical Formula 3 was added as an additive in an amount of 1 wt% based on 100 wt% of the total electrolyte.

[0136] [C3] [ka]

[0137] Evaluation example: Evaluation of high-temperature storage characteristics (capacity retention rate / DC-IR change rate) The lithium secondary batteries fabricated in Examples 1 to 8 and Comparative Examples 1 and 2 were charged and discharged once at 0.2 C, and the charge and discharge capacities were measured (before high-temperature storage).

[0138] In addition, the lithium secondary batteries fabricated in Examples 1 to 8 and Comparative Examples 1 and 2 were charged to 100% SOC (a state in which the battery was charged to 100% charge capacity when the total charge capacity of the battery was 100%), stored at 60°C for 28 days, and then discharged at 0.2 C to 3.0 V under static current conditions to measure the initial discharge capacity. The ratio of the initial discharge capacity to the initial discharge capacity was expressed as the capacity retention capacity.

[0139] For the lithium secondary batteries fabricated in Examples 1 to 8 and Comparative Examples 1 and 2, the ΔV / ΔI (change in voltage / change in current) values ​​for DC-IR were measured, and then the maximum energy state inside the battery was set to a fully charged state (SOC 100%). In this state, the batteries were stored at a high temperature (60°C) for 28 days, and then DC-IR was measured. The DC-IR increase rate (%) was calculated according to the following Equation 1, and the results are shown in Table 1 below.

[0140] [Formula 1] DC-IR increase rate = (DC-IR after 28 days / initial DC-IR) * 100

[0141] [Table 1]

[0142] Referring to Table 1, when EB was used as a solvent and the first compound was used as an additive (Examples 1 to 5), the resistance increase rate was not high compared to when an electrolyte solution without any additives was used (Comparative Example 1), and the capacity retention rate was improved.

[0143] When the content (e.g., concentration) of the additive is the same (Example 1 and Comparative Example 2), even if the same sulfone-based additive is used, the resistance increase rate is not higher when the first compound is used as the additive (Example 1) than when the second compound is used as the additive (Comparative Example 2), and the capacity retention rate is improved.

[0144] When the content of the first compound was the same (Example 2 and Examples 4 to 5), the resistance retention rate was the lowest and the capacity retention rate was the highest when the content of the EB solvent was 75 vol %.

[0145] As used herein, phrases such as "at least one of," "one of," and "selected from," when preceding a list of elements, modify the entire list of elements, not individual elements of the list. For example, "at least one of a, b, or c," "at least one selected from a, b, and c," "at least one selected from a through c," etc., can refer to a only, b only, c only, both a and b (e.g., simultaneously), both a and c (e.g., simultaneously), both b and c (e.g., simultaneously), all of a, b, and c, or variations thereof. As used herein, " / " can be interpreted as either "and" or "or," depending on the context.

[0146] In the context of this disclosure, unless otherwise defined, the terms "use," "uses," and "used" are considered synonymous with the terms "utilize," "utilize," and "utilized," respectively.

[0147] In this disclosure, the term "Group" as used herein refers to a Group of the Periodic Table of the Elements according to the International Union of Pure and Applied Chemistry ("IUPAC") Group 1-18 classification system.

[0148] The term "substantially" and similar terms are used as terms of approximation, not as terms of degree, and are intended to take into account inherent variations in measurements or calculations that would be recognized by one of ordinary skill in the art. Additionally, the term "about" and similar terms, when used herein in connection with a numerical value or numerical range, includes the stated value and values ​​within an acceptable range of deviation from the particular value that would be determined by one of ordinary skill in the art, taking into account the error associated with the measurement in question and the measurement of the particular quantity (e.g., limitations of the measurement system). For example, "about" can refer to within one or more standard deviations, or within ±30%, 20%, 10%, or 5% of the stated value.

[0149] Additionally, numerical ranges recited herein are intended to include all subranges of the same numerical precision subsumed within the recited range. For example, a range of "1.0 to 10.0" is intended to include all subranges between (and including) the recited minimum value of 1.0 and the recited maximum value of 10.0, i.e., having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as 2.4 to 7.6. Each maximum numerical limitation recited herein is intended to include all lower numerical limitations subsumed therein, and each minimum numerical limitation recited herein is intended to include all higher numerical limitations subsumed therein. Accordingly, applicants reserve the right to amend this specification (including the claims) to expressly recite any subranges subsumed within the ranges expressly recited herein.

[0150] A battery management system (BMS) device according to embodiments of the present invention described herein, and / or any other related devices or components, may be implemented using any suitable hardware, firmware (e.g., application-specific integrated circuits), software, or a combination of software, firmware, and hardware. For example, various components of a device may be formed on a single integrated circuit (IC) chip or on separate IC chips. Furthermore, various components of a device may be implemented on a flexible printed circuit film, a tape carrier package (TCP), a printed circuit board (PCB), or a single substrate. Furthermore, various components of a device may be processes or threads running on one or more processors within one or more computing devices, executing computer program instructions and interacting with other system components to perform various functionality described herein. The computer program instructions are stored in memory implemented in the computing device using standard memory devices, such as random access memory (RAM). The computer program instructions may also be stored on other non-transitory computer-readable media, such as a CD-ROM, a flash drive, etc. Additionally, those skilled in the art should recognize that the functionality of various computing devices may be combined or integrated into a single computing device, or the functionality of a particular computing device may be distributed across one or more other computing devices, without departing from the scope of the present disclosure.

[0151] Those skilled in the art will understand that, in view of this disclosure as a whole, each suitable feature of the various embodiments of the disclosure may be combined or combined with one another, either in part or in whole, and may operate technically in conjunction with one another in various suitable ways, and that each embodiment may be implemented independently of one another or in conjunction with one another in any suitable way, unless otherwise stated or suggested.

[0152] Although the preferred embodiment of the present invention has been described above, the present invention is not limited thereto and can be embodied in various modifications within the scope of the claims, the embodiments for implementing the invention, and the accompanying drawings, and it is of course understood that these also fall within the scope of the present invention. [Explanation of symbols]

[0153] 100: Lithium secondary battery 10: Positive electrode 11: Positive electrode lead tab 12: Positive electrode terminal 20: Negative electrode 21: Negative electrode lead tab 22: Negative terminal 30: Separator 40: Electrode assembly 50: Housing 60: Sealing member 70: Electrode tab 71: Positive electrode tab 72: Negative electrode tab

Claims

1. A lithium salt, a non-aqueous organic solvent; an additive, The non-aqueous organic solvent includes a compound represented by the following Chemical Formula 1: The additive comprises a compound represented by the following Chemical Formula 2: [Chemical formula 1] 【Chemical 1】 In the above Chemical Formula 1, R １Ａ and R １Ｂ are each independently hydrogen, halogen, a substituted or unsubstituted C1 to C10 alkyl group, or a substituted or unsubstituted C3 to C10 cycloalkyl group; [Chemical 2] 【Chemistry 2】 In the above Chemical Formula 2, L ２Ａ and L ２Ｂ each independently represents a single bond, a substituted or unsubstituted C1 to C5 alkylene group, a substituted or unsubstituted C2 to C5 alkenylene group, a substituted or unsubstituted C2 to C5 alkynylene group, or a substituted or unsubstituted C6 to C20 arylene group; A and B are each independently a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C6 to C20 aryl group, or a substituted or unsubstituted C2 to C20 heteroaryl group; At least one of A and B is a group represented by the following chemical formula A: [Chemical A] 【Chemistry 3】 In the above chemical formula A, R ２Ａ and R ２Ｂ are each independently hydrogen, halogen, a substituted or unsubstituted C1 to C10 alkyl group, or a substituted or unsubstituted C3 to C10 cycloalkyl group.

2. The R １Ａ 2. The electrolyte solution for a lithium secondary battery according to claim 1, wherein is a substituted or unsubstituted C3 to C10 alkyl group.

3. The R １Ａ The electrolyte solution for a lithium secondary battery according to claim 1 , wherein is a substituted or unsubstituted C3 alkyl group.

4. The R １Ａ The electrolyte solution for a lithium secondary battery according to claim 1 , wherein is an unsubstituted C3 alkyl group.

5. 2. The electrolyte for a lithium secondary battery according to claim 1, wherein the compound represented by Chemical Formula 1 includes at least one of methyl butyrate, ethyl butyrate, and propyl butyrate.

6. 2. The electrolyte solution for a lithium secondary battery according to claim 1, wherein the compound represented by Chemical Formula 1 is contained in an amount of 50 vol % to 95 vol % based on 100 vol % of the total electrolyte solution for a lithium secondary battery.

7. The electrolyte solution for a lithium secondary battery according to claim 1 , wherein the non-aqueous organic solvent further comprises a carbonate-based solvent.

8. Said L １ and L ２ 2. The electrolyte solution for a lithium secondary battery according to claim 1, wherein at least one of the groups is a substituted or unsubstituted C1 to C5 alkylene group.

9. Said L １ and L ２ 2. The electrolyte for a lithium secondary battery according to claim 1, wherein at least one of the groups is a substituted or unsubstituted C2 to C5 alkylene group.

10. The electrolyte for a lithium secondary battery according to claim 1, wherein the chemical formula 2 is represented by the following chemical formula 2-1: [Chemical formula 2-1] 【Chemistry 4】 In the above chemical formula 2-1, L １ and L ２ are each independently a substituted or unsubstituted C2 to C5 alkylene group; R ２１Ａ , R ２１Ｂ , R ２１Ｃ , and R ２１Ｄ are each independently hydrogen, halogen, a substituted or unsubstituted C1 to C10 alkyl group, or a substituted or unsubstituted C3 to C10 cycloalkyl group.

11. The electrolyte for a lithium secondary battery according to claim 1 , wherein the compound represented by the second chemical formula includes at least one of compounds listed in the following first group: [Group 1] 【Chemistry 5】 【Chemistry 6】

12. 2. The electrolyte solution for a lithium secondary battery according to claim 1, wherein the compound represented by the second chemical formula is contained in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the total electrolyte solution for a lithium secondary battery.

13. The additives include vinylene carbonate (VC), fluoroethylene carbonate (FEC), difluoroethylene carbonate, chloroethylene carbonate, dichloroethylene carbonate, bromoethylene carbonate, dibromoethylene carbonate, nitroethylene carbonate, cyanoethylene carbonate, vinylethylene carbonate (VEC), adiponitrile (AN), succinonitrile (SN), 1,3,6-hexanetricyanide (HTCN), propene sultone (PST), propane sultone (PS), lithium tetrafluoroborate (LiBF ４ ), lithium difluorophosphate (LiPO ２ F ２ 2. The electrolyte solution for a lithium secondary battery according to claim 1, further comprising at least one of 2-fluorobiphenyl (2-FBP) and 2-fluorobiphenyl (2-FBP).

14. 2. The electrolyte for a lithium secondary battery according to claim 1, wherein the additive is contained in an amount of 0.1 to 30 parts by weight based on 100 parts by weight of the total electrolyte for a lithium secondary battery.

15. The lithium salt is LiPF ６ 2. The electrolyte solution for a lithium secondary battery according to claim 1, wherein

16. a positive electrode including a positive electrode active material; a negative electrode including a negative electrode active material; A lithium secondary battery comprising the electrolyte solution for lithium secondary batteries according to claim 1 .

17. 17. The lithium secondary battery according to claim 16, wherein the positive electrode active material comprises a lithium nickel-based oxide, a lithium cobalt-based oxide, a lithium manganese-based oxide, a lithium iron phosphate-based oxide, a cobalt-free nickel-manganese-based oxide, or a combination thereof.

18. 17. The lithium secondary battery of claim 16, wherein the negative electrode active material comprises a carbon-based negative electrode active material, a Si-based negative electrode active material, or a combination thereof.

19. The lithium secondary battery according to claim 16, wherein the lithium secondary battery is a pouch-type battery.

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