Non-aqueous electrolyte and lithium secondary battery comprising the same

Abstract

The present invention relates to a nonaqueous electrolyte comprising a lithium salt, an organic solvent, and an additive, wherein the additive comprises a compound represented by Chemical Formula 1, the additive comprises at least one of the compound represented by Chemical Formula 1, ethylene sulfate, and 1,3-propane sultone, the content of the compound represented by Chemical Formula 1 in the nonaqueous electrolyte is 0.25 to 1.60% by weight based on the total weight of the nonaqueous electrolyte, and the total content of the compound represented by Chemical Formula 1, ethylene sulfate, and 1,3-propane sultone can be 0.25 to 1.60% by weight.[Chemical Formula 1]In Chemical Formula 1, R1 is -O-NO2, L1 is an alkylene oxy group having 1 to 5 carbon atoms, M is a metal cation or an organic cation, a is the valence of M when M is a metal cation, a is 1 when M is an organic cation, and a = b.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2024-0104253, filed on August 5, 2024, the disclosure of which is incorporated herein by reference. Technical Field

[0003] This invention relates to a non-aqueous electrolyte and a lithium secondary battery containing the non-aqueous electrolyte. Background Technology

[0004] As modern society becomes increasingly reliant on electricity, the development of large-capacity energy storage devices capable of providing stable power and increasing output has attracted significant attention. Furthermore, with the performance improvements of electronic products ranging from small devices like mobile phones to medium and large electronic devices such as electric vehicles, the demand for high-capacity portable power supplies is growing. Lithium-ion batteries, with their highest potential, can meet the requirements for high-capacity energy storage performance and are therefore used in various applications, from small electronic devices to electric vehicles (EVs) and energy storage systems (ESS).

[0005] Lithium-ion rechargeable batteries typically consist of a positive electrode containing a positive active material, a negative electrode containing a negative active material, an electrolyte serving as the lithium-ion transport medium, and a separator. In this case, carbon-based active materials, silicon-based active materials, lithium transition metal oxides, and lithium metal can be used as the negative active material. Alternatively, lithium transition metal oxides such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), lithium nickel cobalt manganese composite oxides, or lithium iron phosphate can be used as the positive active material.

[0006] When a lithium-ion battery is charged, lithium ions are generated from the positive electrode. These ions may accumulate at the negative electrode or be converted into an alloy form and stored there. The discharge process proceeds in the opposite direction. Theoretically, the movement of lithium ions towards the positive and negative electrodes during charging and discharging should be reversible. However, the actual movement of lithium within the battery may be partially irreversible. Specifically, the medium through which lithium ions are transported is the electrolyte. During charging, most lithium ions are deposited / alloyed within the negative electrode active material. However, some lithium ions are reduced along with the organic and inorganic materials constituting the electrolyte, forming nanoscale organic-inorganic composites on the surface of the negative electrode material. This represents an irreversible and permanent loss of lithium ions provided by the positive electrode. This organic-inorganic film is called the solid electrolyte interphase (SEI) layer. The SEI layer can also be formed on the surface of the positive electrode active material through oxidation reactions of the electrolyte-forming materials. When the SEI layer is formed, the irreversible loss of lithium ions may be reduced, and the driving potential of the electrolyte can be largely ensured, thus enabling smooth and reversible movement of lithium ions between the positive and negative electrodes. Depending on their composition, these solid electrolyte interface layers can also help lower the energy barrier required for lithium ions to transfer charge to the negative or positive electrode. Therefore, properly designing solid electrolyte interface layers has become a research task for improving the performance of lithium secondary batteries.

[0007] Specifically, the lifespan and durability of lithium-ion batteries depend on the stability of the solid electrolyte interface layer. For example, as a lithium-ion battery is charged and discharged, due to the instability of the initially formed solid electrolyte interface layer, additional lithium-ion reduction may occur on the surface of the negative electrode material, potentially leading to the formation of a film thicker than the initially formed solid electrolyte interface layer. Due to the additional loss of lithium ions, a thicker interface layer than the initially formed solid electrolyte interface layer may also form on the surface of the positive electrode material, or structural degradation of the positive electrode material may occur. This may be one reason for the increased resistance of lithium-ion batteries. When a lithium-ion battery is exposed to high temperatures, the materials constituting the electrolyte may decompose, thus the electrolyte performance may deteriorate due to the generated byproducts, and the resistance of the lithium-ion battery may increase. As a lithium-ion battery is exposed to high temperatures and repeated charge and discharge cycles, due to the increased resistance, the positive and negative electrodes may be driven at voltages higher or lower than their initial lifespan, thereby accelerating the electrolyte oxidation and reduction reactions at both electrodes, leading to performance degradation of the lithium-ion battery. Furthermore, due to the instability of the solid electrolyte interface layer, continuous oxidation and reduction reactions of the electrolyte may occur, generating gas inside the lithium-ion battery. In other words, from the perspective of stabilizing lithium secondary batteries and ensuring battery performance such as long lifespan, high-temperature durability, and reduced gas generation, improving the stability of the solid electrolyte interface layer is an important task.

[0008] [Existing Technical Documents]

[0009] [Patent Literature]

[0010] Korean Patent Publication No. 10-2377944 Summary of the Invention

[0011] Technical issues

[0012] The present invention aims to solve the above problems and provide a non-aqueous electrolyte that can enhance the stability of the solid electrolyte interface layer formed on the negative electrode and the positive electrode, enhance the structural stability of the positive electrode by suppressing lithium loss of the positive electrode, and contain components with low resistance to ensure excellent durability and stability at low temperature, room temperature and high temperature.

[0013] Furthermore, the present invention aims to provide a lithium secondary battery with improved overall performance by including the aforementioned non-aqueous electrolyte, which improves low-temperature life, low-temperature output, high-speed charging, room temperature life, high-temperature storage characteristics, and high-temperature life characteristics.

[0014] Technical solution

[0015] [1] The present invention provides a non-aqueous electrolyte comprising a lithium salt, an organic solvent and an additive, wherein the additive comprises a compound represented by Formula 1, the additive comprising at least one of the following compounds represented by Formula 1, ethylene sulfate and 1,3-propanesulfonyl lactone, wherein the content of the compound represented by Formula 1 in the non-aqueous electrolyte is from 0.25% by weight to 1.60% by weight, and the total content of the compound represented by Formula 1, ethylene sulfate and 1,3-propanesulfonyl lactone is from 0.25% by weight to 1.60% by weight based on the total weight of the non-aqueous electrolyte.

[0016] [Chemical Formula 1]

[0017] In the above chemical formula 1, R1 is -O-NO2, L1 is an alkyleneoxy group having 1 to 5 carbon atoms, and M is a metal cation or an organic cation, wherein when M is a metal cation, a is the valence of M, when M is an organic cation, a is 1, and a = b.

[0018] [2] The present invention provides a non-aqueous electrolyte as described in [1], wherein M is a metal cation and M is selected from the group consisting of Li, K, Ca, Mg and Cs.

[0019] [3] The present invention provides a non-aqueous electrolyte as described in one or more of [1] and [2] above, wherein M is an organic cation and M is any one of the groups selected from compounds represented by the following chemical formulas M-1 to M-6.

[0020] [Chemical Formula M-1]

[0021] In the above chemical formula M-1, X M1 -N(R) M15 )- or -S-, and R M11 R M12 R M13 R M14 and R M15 Each of the following is independently hydrogen, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, a cyanoethyl group having 1 to 12 carbon atoms, an alkoxyalkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. [Chemical formula M-2]

[0022] In the above chemical formula M-2, X M2 -N(R) M25 )- or -S-, and R M21 R M22 R M23 R M24 and R M25 Each of the following is independently hydrogen, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, a cyanoethyl group having 1 to 12 carbon atoms, an alkoxyalkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. [Chemical Formula M-3]

[0023] In the above chemical formula M-3, R M31 R M32 R M33 R M34 R M35 and R M36 Each of the following is independently hydrogen, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, a cyanoethyl group having 1 to 12 carbon atoms, an alkoxyalkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. [Chemical formula M-4]

[0024] In the above chemical formula M-4, R M41 R M42 RM43 and R M44 Each of the following is independently hydrogen, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, a cyanoethyl group having 1 to 12 carbon atoms, an alkoxyalkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms, and R M41 R M42 R M43 and R M44 At least two of them can bond with each other to form an aliphatic hydrocarbon ring. [Chemical Formula M-5]

[0025] In the above chemical formula M-5, R M51 R M52 R M53 and R M54 Each of the following is independently hydrogen, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, a cyanoethyl group having 1 to 12 carbon atoms, an alkoxyalkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms, and R M51 R M52 R M53 and R M54 At least two of them can bond with each other to form an aliphatic hydrocarbon ring. [Chemical Formula M-6]

[0026] In the above chemical formula M-6, R M61 R M62 and R M63 Each of the following is independently hydrogen, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, a cyanoethyl group having 1 to 12 carbon atoms, an alkoxyalkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms, and R M61 R M62 and R M63 At least two of them can bond with each other to form an aliphatic hydrocarbon ring.

[0027] [4] The present invention provides non-aqueous electrolytes as described in one or more of [1] to [3] above, wherein the compounds represented by the above chemical formula 1 comprise the compounds represented by the following chemical formulas 1-A: [Chemical Formula 1-A]

[0028] In the above chemical formula 1-A, M, a, b and R1 are each as defined in the above chemical formula 1.

[0029] [5] The present invention provides non-aqueous electrolytes as described in one or more of [1] to [4] above, wherein the compounds represented by the above chemical formula 1 comprise compounds represented by the following chemical formula 1-A-1: [Chemical Formula 1-A-1]

[0030] In the above chemical formula 1-A-1, M, a, and b are each as defined in the above chemical formula 1.

[0031] [6] The present invention provides non-aqueous electrolytes as described in one or more of [1] to [5] above, wherein the compounds represented by the above chemical formula 1 comprise compounds represented by the following chemical formula 1-a-1: [Chemical Formula 1-a-1]

[0032] [7] The present invention provides a non-aqueous electrolyte as described in one or more of [1] to [6] above, wherein the total content of the compound represented by the above chemical formula 1, ethylene sulfate and 1,3-propanesulfonyl lactone is 0.75% to 1.60% by weight based on the total weight of the non-aqueous electrolyte.

[0033] [8] The present invention provides a non-aqueous electrolyte as described in one or more of [1] to [7] above, wherein the additive further comprises at least one selected from cyclic carbonate compounds, nitrile compounds, benzene compounds, lithium salt compounds, amine compounds and silane compounds.

[0034] [9] The present invention provides a non-aqueous electrolyte as described in one or more of [1] to [8] above, wherein the organic solvent comprises a carbonate organic solvent.

[0035]

[10] The present invention provides a non-aqueous electrolyte as described in one or more of [1] to [9] above, wherein the carbonate organic solvent comprises cyclic carbonate organic solvents and linear carbonate organic solvents.

[0036]

[11] The present invention provides a lithium secondary battery comprising a positive electrode, a negative electrode opposite to the positive electrode, a separator disposed between the negative electrode and the positive electrode, and a non-aqueous electrolyte as described in one or more of [1] to

[10] above.

[0037]

[12] The present invention provides a lithium secondary battery as described in

[11] above, wherein the negative electrode comprises a negative electrode active material, wherein the negative electrode active material comprises at least one selected from carbon-based active materials and silicon-based active materials.

[0038]

[13] The present invention provides a lithium secondary battery as described in one or more of

[11] and

[12] above, wherein the negative electrode comprises a negative electrode active material, wherein the negative electrode active material comprises at least one selected from carbon-based active materials and silicon-based active materials.

[0039] Beneficial effects

[0040] The non-aqueous electrolyte of the present invention comprises an additive, wherein the additive contains a compound (represented by Formula 1) in the form of a salt containing an organic sulfonyl group and nitrogen and oxygen within a specific content range. Furthermore, the additive may optionally contain ethylene sulfate and / or 1,3-propane sulpholactone together with the compound represented by Formula 1, and their content range is adjusted to a specific range. When the content is within the above range, a film capable of reducing resistance while exhibiting strong durability can be formed on the surfaces of the positive and negative electrodes. Therefore, when this non-aqueous electrolyte of the present invention is applied to a lithium secondary battery, it exhibits excellent lifespan and storage performance even under conditions such as high temperature and high voltage, and can improve output performance at low temperatures. Attached Figure Description

[0041] Figure 1 The XIC results for the compound represented by chemical formula 1-a-1 are shown.

[0042] Figure 2 The MS spectrum of the compound represented by chemical formula 1-a-1 is shown.

[0043] Figure 3 The MS / MS analysis results (tandem mass spectrometry, dual mass spectrometry) of the compound represented by chemical formula 1-a-1 are shown.

[0044] Figure 4 The preparation solution of the compound represented by chemical formula 1-a-1 is shown. 1 H-NMR spectrum.

[0045] Figure 5 This is an evaluation graph showing the cycle capacity retention of the lithium secondary batteries in the examples and comparative examples. Detailed Implementation

[0046] It will be understood that the terms or words used in this specification and claims are for illustrative purposes only and should not be construed as having the meanings defined in common dictionaries. Rather, they should be interpreted as having meanings and concepts consistent with the technical ideas of the invention, based on the principle that the inventors may appropriately define the concepts of the terms to best interpret the invention.

[0047] For example, it will be further understood that the terms “comprising,” “including,” or “having” in this specification specify the presence of the stated features, figures, steps, elements, or combinations thereof, but do not exclude the presence or inclusion of one or more other features, figures, steps, elements, or combinations thereof.

[0048] Furthermore, in the description of "a to b carbon atoms" in this specification, "a" and "b" respectively represent the number of carbon atoms contained in a specific functional group. That is, the functional group can contain "a" to "b" carbon atoms. For example, "alkylene with 1 to 5 carbon atoms" refers to an alkylene containing 1 to 5 carbon atoms, namely, -CH2-, -CH2CH2-, -CH2CH2CH2-, -CH2(CH2)CH-, -CH2CH2CH2CH2CH2-, and -CH(CH2)CH2CH2-.

[0049] Furthermore, in this specification, the term "alkylene" refers to a branched or unbranched aliphatic hydrocarbon group or functional group in the form of having a hydrogen atom removed from each of the carbon atoms at both ends of the aliphatic hydrocarbon group. In one embodiment, the alkylene group may be substituented or unsubstituented. Alkylene groups include methylene, ethylene, propylene, isopropylene, butylene, isobutylene, tert-butylene, pentylene, and 3-pentylene, etc., and in other embodiments they may optionally have substituents.

[0050] Unless otherwise defined in the specification, the term "substitution" means that at least one hydrogen atom bonded to carbon is replaced by another element, such as fluorine.

[0051] Furthermore, unless otherwise specified in this invention, the expression " "" indicates the binding site in the chemical formula.

[0052] The invention will be described in more detail below.

[0053] Non-aqueous electrolytes

[0054] This invention relates to non-aqueous electrolytes, and more specifically to non-aqueous electrolytes for lithium secondary batteries.

[0055] Specifically, the non-aqueous electrolyte of the present invention comprises: a lithium salt; an organic solvent; and an additive, wherein the additive comprises a compound represented by Chemical Formula 1, and the additive comprises at least one of the compound represented by Chemical Formula 1, ethylene sulfate, and 1,3-propanesulfonyl lactone; the content of the compound represented by Chemical Formula 1 in the non-aqueous electrolyte is from 0.25% by weight to 1.60% by weight, and the total content of the compound represented by Chemical Formula 1, ethylene sulfate, and 1,3-propanesulfonyl lactone is from 0.25% by weight to 1.60% by weight based on the total weight of the non-aqueous electrolyte.

[0056] [Chemical Formula 1]

[0057] In chemical formula 1, R1 is -O-NO2, L1 is an alkyleneoxy group having 1 to 5 carbon atoms, M is a metal cation or an organic cation, when M is a metal cation, a is the valence of M, when M is an organic cation, a is 1, and a = b.

[0058] The non-aqueous electrolyte of the present invention comprises an additive, wherein the additive contains a compound (represented by Formula 1) in the form of a salt containing an organic sulfonyl group and nitrogen and oxygen within a specific content range. Furthermore, the additive may optionally contain ethylene sulfate and / or 1,3-propane sulpholactone together with the compound represented by Formula 1, and their content range is adjusted to a specific range. When the content is within the above range, a film capable of reducing resistance while exhibiting strong durability can be formed on the surfaces of the positive and negative electrodes. Therefore, when this non-aqueous electrolyte of the present invention is applied to a lithium secondary battery, it exhibits excellent lifespan and storage performance even under conditions such as high temperature and high voltage, and can improve output performance at low temperatures.

[0059] 1) Lithium salts

[0060] As the lithium salt used in this invention, various lithium salts commonly used in non-aqueous electrolytes for lithium secondary batteries can be used without limitation. For example, the lithium salt may contain Li + It is a cation and may contain at least one selected from the group consisting of: F - Cl - ,Br - I - NO3 - N(CN)2 - BF4 - ClO4 - AlO2 - AlO4 - AlCl4 - PF6 -SbF6 - AsF6 - B 10 Cl 10 - BF2C2O4 - BC4O8 - PF4C2O4 - PF2C4O8 - (CF3)2PF4 - (CF3)3PF3 - (CF3)4PF2 - (CF3)5PF - (CF3)6P - CF3SO3 - C4F9SO3 - CF3CF2SO3 - (FSO2)2N - CF3CF2(CF3)2CO - (CF3SO2)2CH - CH3SO3 - CF3(CF2)7SO3 - CF3CO2 - CH3CO2 - SCN - and (CF3CF2SO2)2N - .

[0061] Specifically, the lithium salt includes those selected from LiCl, LiBr, LiI, LiBF4, LiClO4, LiAlO2, LiAlO4, LiAlCl4, LiPF6, LiSbF6, LiAsF6, and LiB. 10 Cl 10 The lithium salt comprises at least one selected from the group consisting of LiBF4, LiClO4, LiPF6, LiBOB (LiB(C2O4)2), LiCF3SO3, LiTFSI (LiN(SO2CF3)2), LiFSI (LiN(SO2F)2), and LiBETI (LiN(SO2CF2CF3)2). Specifically, the lithium salt comprises at least one selected from the group consisting of LiBF4, LiClO4, LiPF6, LiBOB (LiB(C2O4)2), LiCF3SO3, LiTFSI (LiN(SO2CF3)2), LiFSI (LiN(SO2F)2), and LiBETI (LiN(SO2CF2CF3)2).

[0062] The concentration of the lithium salt in the non-aqueous electrolyte can be from 0.5 M to 5.0 M, specifically from 0.8 M to 4.0 M, and more specifically from 0.8 M to 2.5 M. When the lithium salt concentration meets the above range, this can improve the performance of Li... + This improves the battery's output characteristics by increasing the transport number and the degree of lithium-ion dissociation.

[0063] Alternatively, lithium salts may be included in the non-aqueous electrolyte in the remainder, excluding, for example, organic solvents and additives described later.

[0064] 2) Organic solvents

[0065] The organic solvent is a non-aqueous solvent commonly used in lithium secondary batteries. There are no restrictions as long as it can minimize the decomposition caused by oxidation reactions during the charging and discharging process of the battery.

[0066] Organic solvents can be included in non-aqueous electrolytes in the remainder, excluding, for example, lithium salts and additives.

[0067] Specifically, the organic solvent may include carbonate organic solvents. Carbonate organic solvents may specifically include at least one selected from cyclic carbonate organic solvents and linear carbonate organic solvents, and more specifically, may include cyclic carbonate organic solvents and linear carbonate organic solvents.

[0068] More specifically, cyclic carbonate organic solvents are organic solvents with high viscosity and high dielectric constant, and are therefore organic solvents that can readily dissociate lithium salts in electrolytes. Specific examples may include at least one organic solvent selected from ethylene carbonate (EC), fluoroethylene carbonate (FEC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentene carbonate, 2,3-pentene carbonate, and vinylene carbonate. More specifically, they may include at least one selected from the group consisting of ethylene carbonate (EC) and fluoroethylene carbonate (FEC), and even more specifically, they may include ethylene carbonate (EC).

[0069] Furthermore, linear carbonate organic solvents are solvents with low viscosity and low dielectric constant, specifically including at least one selected from dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl ethyl carbonate (EMC), methyl propyl carbonate (MPC), and ethyl propyl carbonate (EPC), more specifically, including at least one selected from methyl ethyl carbonate and dimethyl carbonate. Even more specifically, it may include methyl ethyl carbonate and dimethyl carbonate.

[0070] When the carbonate organic solvent includes cyclic carbonate organic solvents and linear carbonate organic solvents, the weight ratio of cyclic carbonate organic solvents to linear carbonate organic solvents can be 10:90 to 50:50, specifically 15:85 to 45:55, more specifically 15:85 to 40:60, and even more specifically 20:80 to 40:60.

[0071] The organic solvent may also include at least one of the following: ester organic solvents, ether organic solvents, glycol ether solvents, and nitrile organic solvents, together with carbonate organic solvents.

[0072] Ester organic solvents may include at least one selected from linear ester organic solvents and cyclic ester organic solvents. Linear ester organic solvents may include at least one selected from methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, propyl propionate, and butyl propionate. Cyclic ester organic solvents may specifically include at least one selected from the group consisting of γ-butyrolactone, γ-valerolactone, γ-caprolactone, σ-valerolactone, and ε-caprolactone.

[0073] As an ether solvent, any one or a mixture of two or more of dimethyl ether, diethyl ether, dipropyl ether, methyl ethyl ether, methyl propyl ether, ethyl propyl ether, 1,3-dioxolane (DOL) and 2,2-bis(trifluoromethyl)-1,3-dioxolane (TFDOL) can be used, but not limited thereto.

[0074] Glycol ether solvents have a high dielectric constant and low surface tension compared to linear carbonate organic solvents, and may include, but are not limited to, at least one selected from dimethoxyethane (glycol ether, DME), diethoxyethane, diethylene glycol ether, triethylene glycol ether, and tetraethylene glycol ether (TEGDME) as a solvent with low reactivity with metals.

[0075] The nitrile solvent may include at least one selected from the group consisting of acetonitrile, propionitrile, butyronitrile, valerate, octanoic acid, heptanoic acid, cyclopentaneformitrile, cyclohexaneformitrile, 2-fluorobenzyl nitrile, 4-fluorobenzyl nitrile, difluorobenzyl nitrile, trifluorobenzyl nitrile, phenylacetonitrile, 2-fluorophenylacetonitrile, and 4-fluorophenylacetonitrile, but is not limited thereto.

[0076] The organic solvent may consist solely of carbonate-based organic solvents. Even if only carbonate-based organic solvents are used as the organic solvent, this is preferred because non-aqueous electrolyte components such as the additives described below can be readily dissolved, and appropriate lithium salt mobility and non-aqueous electrolyte viscosity can be achieved.

[0077] 3) Additives

[0078] The additive comprises a compound represented by Chemical Formula 1. Furthermore, the content of the compound represented by Chemical Formula 1 in the non-aqueous electrolyte is from 0.25% to 1.60% by weight. Based on the total weight of the non-aqueous electrolyte, the content of the compound represented by Chemical Formula 1 is from 0.25% to 1.60% by weight.

[0079] [Chemical Formula 1]

[0080] In chemical formula 1, R1 is -O-NO2, L1 is an alkyleneoxy group having 1 to 5 carbon atoms, M is a metal cation or an organic cation, when M is a metal cation, a is the valence of M, when M is an organic cation, a is 1, and a = b.

[0081] The compound represented by the above chemical formula 1 contains a salt form compound comprising an organic sulfonyl group, nitrogen, and oxygen, thereby forming a film with strong durability on the positive and negative electrode surfaces and reducing resistance.

[0082] Specifically, the compound represented by Formula 1 contains an organic sulfonyl group in its structure, which is reduced and decomposed before the organic solvent during charging and discharging, thereby uniformly forming a solid electrolyte interface layer containing lithium sulfide and lithium sulfide oxide on the negative electrode surface, exhibiting excellent ion conductivity. Since it can function as an effective ion transporter, it can suppress the degradation of both the negative and positive electrodes. Furthermore, due to the excellent durability of the solid electrolyte interface layer derived from this functional group, it can prevent the deterioration of the solid electrolyte interface layer and the resulting dissolution of transition metals from the positive electrode. In addition, the compound represented by Formula 1 included as an additive can contain nitrogen as an anion terminal group in its structure, thereby forming a solid electrolyte interface layer containing lithium nitride, lithium nitrate, lithium oxide, etc., on the negative electrode surface. This can improve the lithium-ion diffusion within the solid electrolyte interface layer, reduce resistance, exhibit excellent high-temperature durability, minimize reversible lithium-ion loss, and prevent side reactions between the electrolyte and the positive electrode, thereby effectively suppressing the dissolution of transition metals from the positive electrode.

[0083] Furthermore, with existing lithium nitrate additives (such as LiNO3), when introduced into the electrode film composition, the growth of an uneven solid electrolyte interface layer induces a reduction reaction in the organic solvent, leading to increased resistance and deterioration of output performance. In addition, lithium nitrate additives are poorly soluble in carbonate organic solvents. On the other hand, the compound represented by the above-described chemical formula 1 of the present invention is a salt-form compound containing an organic sulfonyl group and nitrogen, which can form a uniform solid electrolyte interface layer, suppress the reduction reaction of organic solvents, and form a low-resistance electrode film, thus improving output performance even under low-temperature conditions where lithium-ion transport characteristics are problematic.

[0084] In particular, when the compound represented by the above chemical formula 1 is used as an electrolyte additive, a uniform solid electrolyte interface layer is achieved by simultaneously containing an organic sulfonyl group and nitrogen in a single compound structure. When substances such as lithium nitrate and cyclic sulfates, which do not simultaneously contain an organic sulfonyl group and nitrogen in the compound, are used as electrolyte additives, the solid electrolyte interface layer is formed in particulate or non-uniform form, making it impossible to achieve the effects of preventing the reductive decomposition of organic solvents, forming a low-resistance film, inhibiting the dissolution of transition metals from the positive electrode, and preventing the reduction reaction of transition metal ions.

[0085] In other words, the compound represented by Chemical Formula 1 can form a robust and highly durable electrode film without degrading the lithium-ion transport characteristics and output performance. Therefore, the non-aqueous electrolyte containing the compound represented by Chemical Formula 1 can effectively protect the electrode in environments where electrolyte side reactions, positive electrode breakdown, or SEI film rupture of the negative electrode may occur, such as at high temperatures and high voltages, thereby significantly improving the lifespan and storage performance of lithium secondary batteries, especially at high temperatures and high voltages. In other words, the compound represented by Chemical Formula 1 is highly preferred in terms of achieving improved output performance, lifespan performance, and storage performance of lithium secondary batteries.

[0086] The content of the compound represented by Formula 1 in the above-mentioned non-aqueous electrolyte is from 0.25% to 1.60% by weight. If the content of the compound represented by Formula 1 in the above-mentioned non-aqueous electrolyte is less than 0.25% by weight, it is difficult to sufficiently form an inorganic film containing lithium-nitrogen bonds, lithium-oxygen bonds, lithium-sulfur bonds, etc., on the positive and negative electrode surfaces. If the content of the compound represented by Formula 1 in the above-mentioned non-aqueous electrolyte exceeds 1.60% by weight, problems such as side reactions, capacity degradation, and increased resistance caused by additives may occur. Therefore, in order to achieve the effect produced by the compound represented by Formula 1, it should be used within the above-mentioned range to uniformly form a robust inorganic film containing lithium-nitrogen bonds, lithium-oxygen bonds, lithium-sulfur bonds, etc., on the positive and negative electrode surfaces, while suppressing as many of the disadvantages as possible, such as side reactions, capacity degradation, and increased resistance caused by additives. This effectively suppresses the dissolution of transition metals from the positive electrode and side reactions between the electrolyte and the electrode while effectively playing the role of an ion transporter. As a result, excellent high-temperature durability and low-temperature output performance can be achieved.

[0087] Specifically, the content of the compound represented by the above chemical formula 1 in the non-aqueous electrolyte may be 0.25% by weight or more, 0.28% by weight or more, 0.30% by weight or more, 0.40% by weight or more, 0.50% by weight or more, 0.60% by weight or more, 0.70% by weight or more, 0.80% by weight or more, 0.90% by weight or more, 1.0% by weight or more, 1.20% by weight or more, 1.30% by weight or more, 1.40% by weight or more, or 1.45% by weight or more. The content of the compound represented by the above chemical formula 1 in the non-aqueous electrolyte may be less than 1.60 wt%, less than 1.50 wt%, less than 1.45 wt%, less than 1.40 wt%, less than 1.30 wt%, less than 1.20 wt%, less than 1.10 wt%, less than 1.0 wt%, less than 0.90 wt%, less than 0.80 wt%, less than 0.70 wt%, less than 0.60 wt%, less than 0.50 wt%, less than 0.40 wt%, or less than 0.35 wt%. The above ranges can be combined with each other without limitation.

[0088] In the above chemical formula 1, M can be a metal cation or an organic cation.

[0089] Specifically, when M is a metal cation, M can be any one selected from Li, K, Ca, Mg and Cs, for example, it can be Li.

[0090] Furthermore, when M is an organic cation (i.e., a cation in the form of an organic compound), M can be any of the compounds represented by chemical formulas M-1 to M-6.

[0091] [Chemical Formula M-1]

[0092] In the above chemical formula M-1, X M1 -N(R) M15 )- or -S-, and R M11 R M12 R M13 R M14 and R M15 Each of these is independently hydrogen, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, a cyanoalkyl group having 2 to 12 carbon atoms, an alkoxyalkyl group having 2 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. Specifically, R M11 R M12 R M13 R M14 and R M15Each of these can be independently hydrogen, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, an aryl group having 6 to 12 carbon atoms, a cyanoalkyl group having 2 to 5 carbon atoms, an alkoxyalkyl group having 2 to 10 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. More specifically, R M11 R M12 R M13 R M14 and R M15 Each of these can be independently hydrogen, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, allyl ( -CH2CH=CH2), phenyl, cyanomethyl, 2-cyanoethyl, 3-cyanopropyl, 4-cyanobutyl, methoxymethyl, 2-methoxyethyl, 3-methoxypropyl, methoxy or ethoxy.

[0093] [Chemical formula M-2]

[0094] In the above chemical formula M-2, X M2 -N(R) M25 )- or -S-. Specifically, R M21 R M22 R M23 R M24 and R M25 Each of these can be independently hydrogen, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, a cyanoalkyl group having 2 to 12 carbon atoms, an alkoxyalkyl group having 2 to 12 carbon atoms, or an alkoxy group having 2 to 12 carbon atoms. Specifically, R M21 R M22 R M23 R M24 and R M25 Each of these can be independently hydrogen, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, an aryl group having 6 to 12 carbon atoms, a cyanoalkyl group having 2 to 5 carbon atoms, an alkoxyalkyl group having 2 to 10 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. More specifically, in the above chemical formula M-2, R M21 R M22 R M23 R M24 and R M25 Each of these can be independently hydrogen, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, allyl ( -CH2CH=CH2), phenyl, cyanomethyl, 2-cyanoethyl, 3-cyanopropyl, 4-cyanobutyl, methoxymethyl, 2-methoxyethyl, 3-methoxypropyl, ethoxymethyl, 2-ethoxyethyl, 3-ethoxypropyl, methoxy or ethoxy.

[0095] [Chemical Formula M-3]

[0096] In the above chemical formula M-3, R M31 R M32 R M33 R M34 R M35 and R M36 Each of these is independently hydrogen, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, a cyanoalkyl group having 2 to 12 carbon atoms, an alkoxyalkyl group having 2 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. Specifically, R M31 R M32 R M33 R M34 R M35 and R M36 Each of these can be independently hydrogen, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, an aryl group having 6 to 12 carbon atoms, a cyanoalkyl group having 2 to 5 carbon atoms, an alkoxyalkyl group having 2 to 10 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. More specifically, R M31 R M32 R M33 R M34 R M35 and R M36 Each of these can be independently hydrogen, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, allyl ( -CH2CH=CH2), phenyl, cyanomethyl, 2-cyanoethyl, 3-cyanopropyl, 4-cyanobutyl, methoxymethyl, 2-methoxyethyl, 3-methoxypropyl, ethoxymethyl, 2-ethoxyethyl, 3-ethoxypropyl, methoxy or ethoxy.

[0097] [Chemical formula M-4]

[0098] In the above chemical formula M-4, R M41 R M42 R M43 and R M44Each of these can be independently hydrogen, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, a cyanoalkyl group having 2 to 12 carbon atoms, an alkoxyalkyl group having 2 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. Specifically, R M41 R M42 R M43 and R M44 Each of these can be independently hydrogen, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, an aryl group having 6 to 12 carbon atoms, a cyanoalkyl group having 2 to 5 carbon atoms, an alkoxyalkyl group having 2 to 10 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. More specifically, R M41 R M42 R M43 and R M44 Each of these can be independently hydrogen, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, allyl ( -CH2CH=CH2), phenyl, cyanomethyl, 2-cyanoethyl, 3-cyanopropyl, 4-cyanobutyl, methoxymethyl, 2-methoxyethyl, 3-methoxypropyl, ethoxymethyl, 2-ethoxyethyl, 3-ethoxypropyl, methoxy or ethoxy. In addition, R M41 R M42 R M43 and R M44 At least two of them can bond with each other to form a fatty ring, specifically, R M41 R M42 R M43 and R M44 At least two of them are alkyl groups having 1 to 5 carbon atoms or alkyl groups having 2 to 3 carbon atoms, and these groups can bond to each other to form an aliphatic hydrocarbon ring.

[0099] [Chemical Formula M-5]

[0100] In the above chemical formula M-5, R M51 R M52 R M53 and R M54 Each of these can be independently hydrogen, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, a cyanoalkyl group having 2 to 12 carbon atoms, an alkoxyalkyl group having 2 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. Specifically, R M51 RM52 R M53 and R M54 Each of these can be independently hydrogen, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, an aryl group having 6 to 12 carbon atoms, a cyanoalkyl group having 2 to 5 carbon atoms, an alkoxyalkyl group having 2 to 10 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. More specifically, R M51 R M52 R M53 and R M54 Each of these can be independently hydrogen, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, allyl ( -CH2CH=CH2), phenyl, cyanomethyl, 2-cyanoethyl, 3-cyanopropyl, 4-cyanobutyl, methoxymethyl, 2-methoxyethyl, 3-methoxypropyl, ethoxymethyl, 2-ethoxyethyl, 3-ethoxypropyl, methoxy or ethoxy. In addition, R M51 R M52 R M53 and R M54 At least two of them can bond with each other to form a fatty ring, specifically, R M51 R M52 R M53 and R M54 At least two of them are alkyl groups having 1 to 5 carbon atoms or alkyl groups having 2 to 3 carbon atoms, and these groups can bond to each other to form an aliphatic hydrocarbon ring.

[0101] [Chemical Formula M-6]

[0102] In the above chemical formula M-6, R M61 R M62 and R M63 Each of these can be independently hydrogen, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, a cyanoalkyl group having 2 to 12 carbon atoms, an alkoxyalkyl group having 2 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. Specifically, R M61 R M62 and R M63 Each of these can be independently hydrogen, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, an aryl group having 6 to 12 carbon atoms, a cyanoalkyl group having 2 to 5 carbon atoms, an alkoxyalkyl group having 2 to 10 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. More specifically, R M61 RM62 and R M63 Each of these can be independently hydrogen, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, allyl ( -CH2CH=CH2), phenyl, cyanomethyl, 2-cyanoethyl, 3-cyanopropyl, 4-cyanobutyl, methoxymethyl, 2-methoxyethyl, 3-methoxypropyl, ethoxymethyl, 2-ethoxyethyl, 3-ethoxypropyl, methoxy or ethoxy. In addition, R M61 R M62 and R M63 At least two of them can bond with each other to form a fatty ring, specifically, R M61 R M62 and R M63 At least two of them are alkyl groups having 1 to 5 carbon atoms or alkyl groups having 2 to 3 carbon atoms, and these groups can bond to each other to form an aliphatic hydrocarbon ring.

[0103] Here, in the above chemical formulas M-1 to M-6, the alkoxyalkyl group having 2 to 10 carbon atoms can be represented, for example, R j2 -OR j1 - (in (This refers to the bonding site). Here, R... j1 and R j2 Each can be an alkyl group having 1 to 5 carbon atoms, specifically methyl, ethyl, propyl, butyl or pentyl.

[0104] For example, the compound represented by the above chemical formula M-1 includes at least one compound selected from the group consisting of compounds represented by the following chemical formulas M-1-1 to M-1-10.

[0105] [Chemical Formula M-1-1]

[0106] [Chemical formula M-1-2]

[0107] [Chemical formula M-1-3]

[0108] [Chemical formula M-1-4]

[0109] [Chemical Formula M-1-5]

[0110] [Chemical formula M-1-6]

[0111] [Chemical Formula M-1-7]

[0112] [Chemical formula M-1-8]

[0113] [Chemical Formula M-1-9]

[0114] [Chemical Formula M-1-10]

[0115] The compound represented by the above chemical formula M-2 can be at least one compound selected from the group consisting of compounds represented by the following chemical formulas M-2-1 to M-2-3.

[0116] [Chemical formula M-2-1]

[0117] [Chemical formula M-2-2]

[0118] [Chemical formula M-2-3]

[0119] The compound represented by the above chemical formula M-3 can be at least one compound selected from the group consisting of compounds represented by the following chemical formulas M-3-1 to M-3-6.

[0120] [Chemical Formula M-3-1]

[0121] [Chemical formula M-3-2]

[0122] [Chemical formula M-3-3]

[0123] [Chemical formula M-3-4]

[0124] [Chemical Formula M-3-5]

[0125] [Chemical formula M-3-6]

[0126] The compound represented by the above chemical formula M-4 can be at least one compound selected from the group consisting of compounds represented by the following chemical formulas M-4-1 to M-4-17.

[0127] [Chemical Formula M-4-1]

[0128] [Chemical formula M-4-2]

[0129] [Chemical formula M-4-3]

[0130] [Chemical formula M-4-4]

[0131] [Chemical formula M-4-5]

[0132] [Chemical formula M-4-6]

[0133] [Chemical Formula M-4-7]

[0134] [Chemical formula M-4-8]

[0135] [Chemical Formula M-4-9]

[0136] [Chemical Formula M-4-10]

[0137] [Chemical formula M-4-11]

[0138] [Chemical formula M-4-12]

[0139] [Chemical formula M-4-13]

[0140] [Chemical formula M-4-14]

[0141] [Chemical Formula M-4-15]

[0142] [Chemical Formula M-4-16]

[0143] [Chemical formula M-4-17]

[0144] The compound represented by the above chemical formula M-5 can be at least one compound selected from the group consisting of compounds represented by the following chemical formulas M-5-1 to M-5-14.

[0145] [Chemical Formula M-5-1]

[0146] [Chemical Formula M-5-2]

[0147] [Chemical Formula M-5-3]

[0148] [Chemical Formula M-5-4]

[0149] [Chemical Formula M-5-5]

[0150] [Chemical Formula M-5-6]

[0151] [Chemical Formula M-5-7]

[0152] [Chemical formula M-5-8]

[0153] [Chemical Formula M-5-9]

[0154] [Chemical Formula M-5-10]

[0155] [Chemical Formula M-5-11]

[0156] [Chemical formula M-5-12]

[0157] [Chemical Formula M-5-13]

[0158] [Chemical Formula M-5-14]

[0159] The compound represented by the above chemical formula M-6 can be at least one compound selected from the group consisting of compounds represented by the following chemical formulas M-6-1 to M-6-11.

[0160] [Chemical Formula M-6-1]

[0161] [Chemical formula M-6-2]

[0162] [Chemical formula M-6-3]

[0163] [Chemical Formula M-6-4]

[0164] [Chemical Formula M-6-5]

[0165] [Chemical formula M-6-6]

[0166] [Chemical formula M-6-7]

[0167] [Chemical formula M-6-8]

[0168] [Chemical Formula M-6-9]

[0169] [Chemical Formula M-6-10]

[0170] [Chemical formula M-6-11]

[0171] In the above chemical formula 1, when M is a metal cation, a is the valence of M. For example, for Li, an alkali metal, a is 1; for Ca, an alkaline earth metal, a is 2. When M is an organic cation, a is 1. In the above chemical formula 1, a = b.

[0172] For example, a compound represented by chemical formula 1 may include compounds represented by chemical formula 1-1 below.

[0173] [Chemical Formula 1-1]

[0174] In the above chemical formula 1-1, M, a, b and L1 are each as defined in the above chemical formula 1.

[0175] In the above chemical formula 1, L1 can be an alkyleneoxy group having 1 to 5 carbon atoms. For example, L1 can be -OR L1 -, and R L1 It can be an alkylene group having 1 to 5 carbon atoms. Here, L1 can be an alkylene oxide (e.g., -OR). L1 When -), oxygen (O) can bond with sulfur (S). L1 can specifically be an alkyleneoxy group with 2 to 3 carbon atoms, more specifically an ethyleneoxy group or a propyleneoxy group, and even more specifically an ethyleneoxy group.

[0176] Specifically, the compounds represented by the above chemical formula 1 may include the compounds represented by the following chemical formulas 1-A.

[0177] [Chemical Formula 1-A]

[0178] In the above chemical formula 1-A, M, a, b and R1 are each as defined in the above chemical formula 1.

[0179] More specifically, the compounds represented by the above chemical formula 1 may include the compounds represented by the following chemical formula 1-A-1.

[0180] [Chemical Formula 1-A-1]

[0181] In the above chemical formula 1-A-1, M, a, and b are each as defined in the above chemical formula 1.

[0182] More specifically, the compounds represented by the above chemical formula 1 may include the compounds represented by the following chemical formula 1-a-1.

[0183] [Chemical Formula 1-a-1]

[0184] For example, compounds represented by Formula 1 can be formed by reacting sulfur oxides (e.g., cyclic sulfur oxides containing sulfate groups (-OS(=O)2-O-)) with metal nitrates (e.g., lithium nitrate, lithium nitrite, etc.), but are not specifically limited thereto. Such reactions can be carried out before the preparation of the non-aqueous electrolyte, or during the preparation of the non-aqueous electrolyte, by adding the aforementioned sulfur oxides and metal nitrates to an organic solvent.

[0185] The presence or absence of the compound represented by chemical formula 1 can be determined by HR-LS / MS (high-resolution liquid chromatography-mass spectrometry) and / or 1 It can be confirmed by 1H-NMR (1H-nuclear magnetic resonance spectroscopy), but is not specifically limited to this.

[0186] In this invention, the additive comprises at least one of the compound represented by Formula 1, ethylene sulfate, and 1,3-propanesulfonyl lactone. That is, the non-aqueous electrolyte of this invention may optionally comprise ethylene sulfate and / or 1,3-propanesulfonyl lactone as additives, together with the compound represented by Formula 1. Alternatively, the non-aqueous electrolyte of this invention may comprise ethylene sulfate and / or 1,3-propanesulfonyl lactone as additives, together with the compound represented by Formula 1, or may comprise only the compound represented by Formula 1. Ethyl sulfate and / or 1,3-propanesulfonyl lactone may be included in the additive to help form a sulfur (S)-containing SEI film.

[0187] Based on the total weight of the non-aqueous electrolyte, the total content of the compound represented by Formula 1, ethylene sulfate, and 1,3-propanesulfonyl lactone is from 0.25% to 1.60% by weight. When the total content of the compound represented by Formula 1, ethylene sulfate, and 1,3-propanesulfonyl lactone based on the total weight of the non-aqueous electrolyte is less than 0.25% by weight, there is a problem that the lifetime performance and / or storage performance may deteriorate due to uneven film formation and the resistance may increase. Furthermore, when the total content of the compound represented by Formula 1, ethylene sulfate, and 1,3-propanesulfonyl lactone based on the total weight of the non-aqueous electrolyte exceeds 1.60% by weight, there is a problem that the electrode film becomes thicker, the battery resistance increases, which may adversely affect charge transfer phenomena, such as output performance degradation, hysteresis, and polarization. Additionally, gaseous byproducts may be generated at positions opposite the positive and negative electrodes, interfering with lithium-ion diffusion and leading to lithium metal electrodeposition, thereby accelerating irreversible capacity loss.

[0188] In this invention, the total content of the compound represented by Chemical Formula 1, ethylene sulfate, and 1,3-propanesulfonyl lactone can refer to, for example: the total content of the compound represented by Chemical Formula 1 and 1,3-propanesulfonyl lactone in the non-aqueous electrolyte when the non-aqueous electrolyte does not contain ethylene sulfate; the total content of the compound represented by Chemical Formula 1 and ethylene sulfate in the non-aqueous electrolyte when the non-aqueous electrolyte does not contain 1,3-propanesulfonyl lactone; and the content of the compound represented by Chemical Formula 1 when the non-aqueous electrolyte does not contain 1,3-propanesulfonyl lactone and ethylene sulfate.

[0189] Specifically, based on the total weight of the non-aqueous electrolyte, the total content of the compound represented by Formula 1, ethylene sulfate, and 1,3-propanesulfonyl lactone can be from 0.75% to 1.60% by weight, from 0.8% to 1.5% by weight, and from 0.9% to 1.5% by weight. When the content is within the above range, not only can the uniformity of the electrode film be improved, but also stable battery performance can be achieved, such as the smooth diffusion of lithium ions.

[0190] If the additive contains ethylene sulfate, the ethylene sulfate content may be less than 1% by weight, less than 0.9% by weight, less than 0.85% by weight, less than 0.81% by weight, less than 0.7% by weight, less than 0.6% by weight, or less than 0.1% by weight, based on the total weight of the non-aqueous electrolytes. When the additive contains ethylene sulfate, the ethylene sulfate content may be greater than 0% by weight, based on the total weight of the non-aqueous electrolytes. The additive may not contain ethylene sulfate.

[0191] If the additive contains 1,3-propanesulfonyl lactone, the content of 1,3-propanesulfonyl lactone may be less than 0.5% by weight, less than 0.3% by weight, less than 0.2% by weight, or less than 0.1% by weight, based on the total weight of the non-aqueous electrolytes. When the additive contains 1,3-propanesulfonyl lactone, the content of 1,3-propanesulfonyl lactone may be greater than 0% by weight, based on the total weight of the non-aqueous electrolytes. The additive may not contain 1,3-propanesulfonyl lactone.

[0192] In addition, to prevent the electrolyte from decomposing under high output conditions and causing the negative electrode to break down, or to further improve the low-temperature high-rate discharge characteristics, high-temperature stability, overcharge protection and battery expansion suppression effect at high temperatures, the additives in the electrolyte may also include auxiliary additives if necessary.

[0193] The auxiliary additives may include at least one selected from the group consisting of cyclic carbonates, nitriles, benzenes, lithium salts, amines, and silanes.

[0194] Cyclic carbonate compounds may be at least one selected from vinylene carbonate (VC) and vinyl ethylene carbonate (VEC).

[0195] Benzene compounds may be fluorobenzene. Amine compounds may be at least one selected from triethanolamine and ethylenediamine. Silane compounds may be at least one selected from tetravinylsilane, tris(trimethylsilyl)phosphate (TMSPa), and tris(trimethylsilyl)phosphite (TMSPi). Lithium salt additives may be at least one selected from lithium dioxolane borate (LiBOB), lithium difluorooxolane borate (LiODFB), and lithium difluorophosphate (LiDFP).

[0196] Nitrile compounds may include at least one compound selected from the group consisting of succinic anionibacterium, adiponitrile, acetonitrile, propionitrile, butyric anionibacterium, valerate, octanoic anionibacterium, heptanoic anionibacterium, cyclopentaneformitrile, cyclohexaneformitrile, 2-fluorobenzyl anionibacterium, 4-fluorobenzyl anionibacterium, difluorobenzyl anionibacterium, trifluorobenzyl anionibacterium, 2-fluorophenylacetonitrile, and 4-fluorophenylacetonitrile.

[0197] Specifically, the auxiliary additive may include at least one selected from vinylene carbonate and fluoroethylene carbonate, specifically vinylene carbonate and fluoroethylene carbonate.

[0198] At the same time, two or more auxiliary additives can be used in combination, and their content can be less than 10% by weight based on the total weight of non-aqueous electrolytes, specifically more than 0.01% by weight and less than 8.0% by weight, more specifically 0.05% by weight to 5.0% by weight, and even more specifically 3% by weight to 5% by weight.

[0199] In this invention, a peak may exist in the V-dQ / dV graph obtained by differentiating the voltage V versus battery capacity Q measured by charging the lithium secondary battery containing the non-aqueous electrolyte, between 1.76 V and 2.25 V.

[0200] In this specification, a "peak" can be defined as the peak point of any peak region present in a V-dQ / dV graph (where the x-axis represents voltage (V) and the y-axis represents dQ / dV), specifically the point within that peak region that has the minimum dQ / dV value. More specifically, any peak region present in the V-dQ / dV graph can refer to the voltage region where a specific component in a non-aqueous electrolyte undergoes a reduction reaction. This can be understood as the reduction reaction of that specific component beginning at the starting point of the peak region (the minimum voltage point of the peak region), maximizing at the peak point of the peak region, and ending at the ending point of the peak region (the maximum voltage point of the peak region). The area of ​​the peak region represents the amount of reduction reaction of the specific component, and the width of the peak region represents the reduction reaction rate of the specific component.

[0201] The peak present at 1.76 V to 2.25 V in the V-dQ / dV plot may originate from the reduction reaction of the compound represented by Formula 1 above. In the V-dQ / dV plot, the peak present at 1.76 V to 2.25 V can be distinguished from the peak present at 1.0 V to 1.75 V originating from the reduction reaction of compounds that do not contain sulfur-containing functional groups in their structure (such as lithium nitrate), and the peak present at 0.7 V to 1.25 V originating from the reduction reaction of cyclic sulfur oxides (such as ethylene sulfate and 1,3-propanesulfonyl lactone).

[0202] When deriving the V-dQ / dV diagram, the lithium secondary battery can be in the form of a half-cell. Specifically, the lithium secondary battery includes a positive electrode (or can be represented as a first electrode), a negative electrode (or can be represented as a second electrode), a separator, and a non-aqueous electrolyte, wherein the positive electrode contains lithium metal, and the negative electrode contains a negative electrode active material.

[0203] Specifically, the positive electrode may contain lithium metal. Specifically, the positive electrode may be composed of lithium metal. The positive electrode may be in sheet form.

[0204] In the aforementioned negative electrode, the V-dQ / dV diagram is used to evaluate the reduction performance of the non-aqueous electrolyte compared to lithium metal, and there are no particular limitations on the type of negative electrode active material. The negative electrode active material is a material capable of reversibly inserting and deintercalating lithium ions, and may include at least one selected from the group consisting of carbon-based active materials, (quasi-)metallic active materials, and lithium metal. Specifically, it may include at least one selected from carbon-based active materials and (quasi-)metallic active materials, and more specifically, it may include carbon-based active materials. Carbon-based active materials may specifically include graphite, which may be artificial or natural graphite. More specifically, this negative electrode is applicable to the description of the negative electrode of a lithium secondary battery described below. Specifically, the descriptions of the negative electrode current collector, negative electrode active material, negative electrode active material layer, negative electrode active material, and other optional components such as binders and conductive agents are all applicable to this negative electrode.

[0205] Except as described above, the configuration of the lithium secondary battery used to derive the V-dQ / dV diagram may be the same as those described for the lithium secondary battery described in this invention.

[0206] When deriving the V-dQ / dV diagram, the charging process of the lithium secondary battery can refer to its activation process (formation). That is, the lithium secondary battery used in deriving the V-dQ / dV diagram can be an uncharged lithium secondary battery.

[0207] There are no particular restrictions on the charging conditions of lithium-ion batteries. For example, lithium-ion batteries can be charged in constant current / constant voltage (CC / CV) mode, such as at 0.05C and 0.05V cutoff. During the charging process, lithium-ion batteries can be charged at rates from 0.05C to 1C, specifically from 0.1C to 0.5C. During the charging process, the state of charge (SOC) of the lithium-ion battery can be charged from 40% to 100%, specifically from 70% to 100%, and more specifically, the SOC can be charged to 100%.

[0208] In the V-dQ / dV graph obtained by differentiating the voltage V versus battery capacity Q measured by charging a lithium secondary battery, there may be peaks between 1.76 V and 2.25 V, specifically between 1.8 V and 2.2 V, and more specifically between 2.0 V and 2.1 V.

[0209] Lithium secondary batteries

[0210] In addition, the present invention provides a lithium secondary battery comprising the above-mentioned non-aqueous electrolyte.

[0211] Specifically, the lithium secondary battery of the present invention includes a positive electrode, a negative electrode opposite to the positive electrode, a separator disposed between the negative electrode and the positive electrode, and the aforementioned non-aqueous electrolyte. The non-aqueous electrolyte may be the aforementioned non-aqueous electrolyte.

[0212] After housing an electrode assembly containing a positive electrode, a negative electrode opposite the positive electrode, and a separator inserted between the positive and negative electrodes in a battery case, a lithium secondary battery can be prepared by injecting the non-aqueous electrolyte therein.

[0213] Since the non-aqueous electrolyte has already been explained above, the negative electrode, positive electrode, and membrane will be explained below.

[0214] (1) Positive electrode

[0215] The positive electrode can contain positive electrode active materials.

[0216] The positive electrode active material is a compound capable of reversible insertion and extraction. It can be any positive electrode active material used in the art and is not particularly limited. Specifically, it can include lithium metal composite oxides. More specifically, the lithium metal composite oxide can be: layered compounds, such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), or compounds substituted with one or more transition metals; lithium iron oxides, such as LiFe3O4; lithium iron phosphate such as LiFePO4; lithium manganese oxides, such as Li... 1+ c1 Mn 2-c1O4 (0≤c1≤0.33), LiMnO3, LiMn2O3 and LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides, such as LiV3O8, V2O5 and Cu2V2O7; LiNi 1-c2 M c2 O2 (where M is at least one selected from the group consisting of Co, Mn, Al, Cu, Fe, Mg, B, and Ga, and satisfies 0.01 ≤ c2 ≤ 0.3) represents a Ni-site type lithium nickel oxide; LiMn 2-c3 M c3 O2 (where M is at least one selected from the group consisting of Co, Ni, Fe, Cr, Zn and Ta, and satisfies 0.01≤c3≤0.1) or Li2Mn3MO8 (where M is at least one selected from the group consisting of Fe, Co, Ni, Cu and Zn) are lithium manganese composite oxides, but not limited to these. The positive electrode can be a lithium metal positive electrode.

[0217] More specifically, the positive electrode active material may include at least one selected from the group consisting of lithium cobalt oxide (LiCoO2), lithium nickel cobalt manganese oxide, lithium-rich manganese oxide, and lithium iron phosphate. More specifically, the positive electrode active material may include lithium iron phosphate.

[0218] Lithium nickel cobalt manganese oxide can be represented by the following chemical formula P-1.

[0219] [Chemical formula P-1]

[0220] Li 1+x (Ni a Co b Mn c M d O2

[0221] In the above chemical formula P-1, M is one or more selected from 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. 1+x, a, b, c, and d are the independent atomic fractions of the elements, where 0 ≤ x ≤ 0.2, 0.50 ≤ a < 1, 0 < b ≤ 0.25, 0 < c ≤ 0.25, 0 ≤ d ≤ 0.1, and a + b + c + d = 1. Preferably, a, b, c, and d can be 0.70 ≤ a ≤ 0.95, 0.025 ≤ b ≤ 0.20, 0.025 ≤ c ≤ 0.20, and 0 ≤ d ≤ 0.05, respectively. Preferably, a, b, c, and d can be 0.80 ≤ a ≤ 0.95, 0.025 ≤ b ≤ 0.15, 0.025 ≤ c ≤ 0.15, and 0 ≤ d ≤ 0.05, respectively. Preferably, a, b, c, and d can be 0.85 ≤ a ≤ 0.90, 0.05 ≤ b ≤ 0.10, 0.05 ≤ c ≤ 0.10, and 0 ≤ d ≤ 0.03, respectively.

[0222] The over-lithiated manganese-rich oxide may include a compound represented by the following chemical formula P-2.

[0223] [Chemical formula P-2]

[0224] Li 1+s [Ni t Co u Mn v M 1 w O 2+z

[0225] In the above chemical formula P-2, M 1 is one or more selected from 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, where 0.05 ≤ s ≤ 1, 0 ≤ t ≤ 0.5, 0 ≤ u ≤ 0.3, 0.5 ≤ v < 1.0, 0 ≤ w ≤ 0.2, and 0 ≤ z ≤ 1. Preferably, in the above chemical formula B, it can be 0.05 ≤ s ≤ 1.0, 0.1 ≤ t ≤ 0.5, 0 ≤ u ≤ 0.1, 0.5 ≤ v < 1.0, 0 ≤ w ≤ 0.2, and 0 ≤ z ≤ 1. More preferably, in the above chemical formula P-2, it can be 0.10 ≤ s ≤ 0.50, 0.1 ≤ t ≤ 0.5, 0 ≤ u ≤ 0.1, 0.6 ≤ v < 1.0, 0 ≤ w ≤ 0.1, and 0 ≤ z ≤ 0.50.

[0226] [[ID=二十九]]Lithium iron phosphate may include a compound represented by the following chemical formula P-3.

[0227] [Chemical formula P-3]

[0228] Li 1+e Fe 1-g M 2 g (PO 4-f )X f

[0229] In the above chemical formula P-3, M 2 The elements are selected from one or more of Co, Ni, Mn, Al, Mg, Ti, and V, and X is F, S, or N, with 0 ≤ g ≤ 0.5; -0.5 ≤ e ≤ +0.5; and 0 ≤ f ≤ 0.1. The above chemical formula P-3 can be specifically represented as LiFePO4 (g=0, e=0, and f=0).

[0230] The positive electrode active material can be in particulate form. Specifically, the average particle size (D) of the positive electrode active material... 50 The diameter can range from 1 μm to 30 μm.

[0231] To improve its capacity, the content of positive electrode active material in the positive electrode active material layer can be from 70% to 99% by weight, specifically from 80% to 98% by weight.

[0232] The positive electrode may include a positive current collector and a layer of positive active material disposed on at least one surface of the positive current collector. Here, the positive active material may include the aforementioned positive active material.

[0233] The thickness of the positive current collector is typically 3 μm to 500 μm.

[0234] Fine irregularities can be formed on the surface of the positive current collector to improve the adhesion of the positive electrode active material. For example, the positive current collector can be used in various shapes, such as films, sheets, foils, meshes, porous bodies, foams, and nonwoven fabrics.

[0235] The positive electrode active material layer can be disposed on at least one surface of the positive electrode current collector. Specifically, the positive electrode active material layer can be disposed on one or both surfaces of the positive electrode current collector.

[0236] Considering the sufficient capacity of the positive electrode active material, the content of the positive electrode active material in the positive electrode active material layer can be from 80% to 99% by weight.

[0237] The positive electrode active material layer may also include an adhesive and / or conductive material together with the aforementioned positive electrode active material.

[0238] Adhesives are components that assist in the adhesion of active materials, conductive materials, etc., and to current collectors. Specifically, they may include at least one selected from polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyvinylidene fluoride-hexafluoropropylene, polyethylene, polypropylene, ethylene propylene diene monomer (EPDM), sulfonated EPDM, styrene-butadiene rubber, and fluororubber. Preferably, they may include polyvinylidene fluoride.

[0239] To ensure sufficient bonding between components such as the positive electrode active material, the content of the binder in the positive electrode active material layer can be from 1% to 20% by weight, preferably from 1.2% to 10% by weight.

[0240] Conductive materials can be used to assist and improve the conductivity of secondary batteries, as long as they are conductive and do not cause chemical changes, there are no particular limitations. Specifically, the positive electrode conductive material may include at least one selected from the following: graphite, such as natural graphite or artificial graphite; acetylene black, Ketjen black, channel black, furnace black, lamp black, and thermally cracked carbon black; conductive fibers, such as carbon fibers and metal fibers; conductive tubes, such as carbon nanotubes; fluorocarbons; metal powders, such as aluminum and nickel powder; conductive whiskers, such as zinc oxide and potassium titanate; conductive metal oxides, such as titanium dioxide; and polyphenylene derivatives. Preferably, the conductive material may include carbon nanotubes for improving conductivity.

[0241] To ensure sufficient conductivity, the content of conductive material in the positive electrode active material layer can be from 1% to 20% by weight, preferably from 1.2% to 10% by weight.

[0242] The thickness of the positive electrode active material layer can be from 5 μm to 500 μm, preferably from 20 μm to 200 μm.

[0243] The positive electrode can be manufactured by coating a positive current collector with a positive electrode slurry containing a positive electrode active material and optional binders, conductive materials, and a positive electrode slurry, followed by drying and calendering. Alternatively, the positive electrode can be manufactured by preparing a film by mixing the positive electrode active material with optional binders, conductive materials, etc., and then laminating the film onto the positive current collector.

[0244] For the purpose of promoting the dispersion of positive electrode active materials, binders and / or conductive materials, the solvent for forming the positive electrode slurry may include, for example, at least one selected from distilled water, N-methylpyrrolidone, ethanol, methanol and isopropanol, preferably N-methylpyrrolidone.

[0245] (2) Negative electrode

[0246] Next, the negative electrode will be described.

[0247] The negative electrode may contain a negative electrode active material.

[0248] The negative electrode active material is a material capable of reversibly inserting and deintercalating lithium ions, and may include at least one selected from the group consisting of carbon-based active materials, (quasi-)metallic active materials, and lithium metal, specifically including at least one selected from carbon-based active materials and (quasi-)metallic active materials. More specifically, the negative electrode active material may include at least one selected from carbon-based active materials and silicon-based active materials.

[0249] Carbon-based active materials may include at least one selected from graphite, hard carbon, soft carbon, carbon black, graphene, and fibrous carbon, and may preferably include graphite. For example, the graphite may be at least one of artificial graphite and natural graphite.

[0250] To ensure structural stability during charging and discharging and to reduce side reactions with the electrolyte, the average particle size (D) of carbon-based active materials is crucial. 50 The diameter can be from 10 μm to 30 μm, preferably from 15 μm to 25 μm.

[0251] Specifically, (quasi)metallic active materials may include: at least one selected from Cu, Ni, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Fe, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, V, Ti, and Sn; alloys of lithium with (quasi)metals selected from Cu, Ni, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Fe, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, V, Ti, and Sn; oxides of at least one (quasi)metal selected from Cu, Ni, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Fe, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, V, Ti, and Sn; lithium titanium oxide (LTO); lithium vanadium oxide, etc.

[0252] More specifically, (quasi)metallic active materials may include silicon-based active materials.

[0253] Silicon-based active materials may include those selected from SiO2. x (0≤x<2) represents at least one of the compounds and silicon-carbon composites. Since SiO2 does not react with lithium ions and therefore cannot store lithium, x is preferably within the above range. More preferably, the silicon-based active material can be SiO.

[0254] To ensure structural stability during charging and discharging and to reduce side reactions with the electrolyte, the average particle size (D) of silicon-based active materials is crucial. 50 The diameter can be from 1 μm to 30 μm, preferably from 2 μm to 15 μm.

[0255] In addition, the negative electrode active material may include at least one selected from carbon-based active materials and silicon-based active materials.

[0256] For example, the negative electrode of the present invention may comprise a carbon-based active material and a silicon-based active material. Here, the weight ratio of the silicon-based active material to the carbon-based active material can be from 1:99 to 30:70, specifically from 3:97 to 15:85. When the mixing ratio of the silicon-based active material to the carbon-based active material meets the above range, excellent cycle performance can be ensured because the volume expansion of the silicon-based active material is suppressed while improving capacity characteristics.

[0257] The negative electrode may include a negative current collector and a negative active material layer disposed on at least one surface of the negative current collector. The negative active material layer may contain a negative active material.

[0258] There are no specific restrictions on the negative electrode current collector, as long as it has high conductivity and does not cause adverse chemical changes in the battery. Specifically, copper, stainless steel, aluminum, nickel, titanium, sintered carbon, copper or stainless steel with a surface treatment of carbon, nickel, titanium and silver, and aluminum-cadmium alloys can be used as negative electrode current collectors.

[0259] The thickness of the negative current collector is typically from 3 μm to 500 μm.

[0260] Fine irregularities can be formed on the surface of the negative electrode current collector to improve the adhesion of the negative electrode active material. For example, the negative electrode current collector can be used in various shapes, such as films, sheets, foils, meshes, porous bodies, foams, and nonwoven fabrics.

[0261] The negative electrode active material layer can be disposed on at least one surface of the negative electrode current collector. Specifically, the negative electrode active material layer can be disposed on one or both surfaces of the negative electrode current collector.

[0262] In order to demonstrate sufficient capacity in a secondary battery, the content of the negative electrode active material in the negative electrode active material layer can be from 60% to 99% by weight.

[0263] The negative electrode active material layer may also include conductive materials and / or adhesives together with the aforementioned negative electrode active material.

[0264] Adhesives are used to improve battery performance by improving the adhesion between the negative electrode active material layer and the negative electrode current collector and enhancing the cohesion between the negative electrode active materials.

[0265] Specifically, in order to further improve electrode adhesion and provide sufficient resistance to volume expansion / contraction of the negative electrode active material, the adhesive may include at least one selected from the group consisting of styrene-butadiene rubber (SBR), nitrile rubber (NBR), acrylonitrile butadiene rubber, acrylic rubber, butyl rubber, fluororubber, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl alcohol (PVA), polyacrylic acid (PAA), polyethylene glycol (PEG), polyacrylonitrile (PAN), polyacrylamide (PAM), polyvinylidene fluoride, polytetrafluoroethylene, and polyvinylidene fluoride-hexafluoropropylene.

[0266] The content of the binder in the negative electrode active material layer can be from 1% to 30% by weight. When it is included in the above range, the negative electrode active material can be better bound, thereby minimizing the volume expansion problem of the active material. At the same time, in the preparation process of the slurry for forming the negative electrode active material layer, it can help the binder to disperse and improve the coatability and phase stability of the slurry.

[0267] Conductive agents can be used to assist and improve the conductivity of secondary batteries, as long as they are conductive and do not cause chemical changes; there are no particular limitations. Specifically, conductive materials may include at least one selected from the group consisting of graphite such as natural or artificial graphite, carbon black such as acetylene black, Ketjen black, channel black, furnace black, lamp black, and thermal cracking carbon black, conductive fibers such as carbon fibers or metal fibers, conductive tubes such as carbon nanotubes, fluorocarbons, metal powders such as aluminum and nickel powder, conductive whiskers such as zinc oxide and potassium titanate, conductive metal oxides such as titanium dioxide, and polyphenylene derivatives.

[0268] The content of conductive material in the negative electrode active material layer can be from 1% to 20% by weight. When the content is within the above range, it is preferred to form an excellent conductive network while mitigating the increase in resistance caused by the adhesive.

[0269] The thickness of the negative electrode active material layer can be from 5 μm to 500 μm, preferably from 5 μm to 200 μm.

[0270] The negative electrode can be manufactured by coating a negative electrode current collector with a solvent-based negative electrode slurry containing a negative electrode active material and optional binders, conductive materials, and a negative electrode slurry, followed by drying and calendering. Alternatively, the negative electrode can be fabricated by preparing a film by mixing the negative electrode active material with optional binders, conductive materials, etc., and then laminating the film onto the negative electrode current collector.

[0271] For the purpose of promoting the dispersion of negative electrode active materials, binders and / or conductive materials, the solvent for forming the negative electrode slurry may include, for example, at least one selected from distilled water, N-methylpyrrolidone, ethanol, methanol and isopropanol, preferably distilled water.

[0272] (3) Diaphragm

[0273] The separator separates the negative and positive electrodes and provides a path for the movement of lithium ions. Any separator can be used without particular limitation, as long as it is generally used in lithium secondary batteries. In particular, a separator with high moisture retention capacity for non-aqueous electrolytes due to low resistance to ion transport is preferred.

[0274] Specifically, porous polymer membranes can be used, such as those made from polyolefin polymers (e.g., ethylene homopolymers, propylene homopolymers, ethylene / butene copolymers, ethylene / hexene copolymers, ethylene / methacrylate copolymers, etc.), or multilayered structures of two or more layers can be used. Alternatively, typical porous nonwoven fabrics can be used, such as nonwoven fabrics formed from high-melting-point glass fibers or polyethylene terephthalate fibers. Furthermore, coated diaphragms containing ceramic components or polymer materials can be used to ensure heat resistance or mechanical strength, and diaphragms with single-layer or multilayer structures can be optionally used.

[0275] The shape of the lithium secondary battery of the present invention is not particularly limited, but cylindrical, prismatic, pouch or coin-shaped batteries can be used.

[0276] Furthermore, the lithium secondary battery of the present invention is suitable for use in portable devices such as mobile phones, laptops and digital cameras, as well as electric vehicles such as hybrid electric vehicles (HEVs) and energy storage devices (ESS).

[0277] The present disclosure will be described in more detail below with reference to embodiments. However, the invention may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these exemplary embodiments are provided to make the description sufficiently complete and to fully convey the scope of the disclosure to those skilled in the art.

[0278] Examples and Comparative Examples

[0279] Example 1

[0280] (1) Preparation of the compound represented by chemical formula 1

[0281] Ethyl sulfate and LiNO3 were dissolved in ethyl acetate (EA) at a ratio of 10% by weight to achieve an equivalence ratio of 1.2:1. The mixture was then stirred at room temperature (15-25°C) to induce the formation of a compound represented by formula 1-a-1. Through this reaction, the compound represented by formula 1, which is insoluble in ethyl acetate (EA), precipitated as a powder. The resulting solution was filtered to obtain a powder. Subsequently, the ethyl acetate solvent remaining in the powder was evaporated to yield the compound represented by formula 1-a-1.

[0282] By HR-LC / MS (high-resolution liquid chromatography-mass spectrometry) and 1 1H NMR (¹H nuclear magnetic resonance spectroscopy) confirmed the presence of the compound represented by the chemical formula 1-a-1.

[0283] First, the compound (powder) represented by the above chemical formula 1-a-1 was added to an organic solvent containing ethylene carbonate, ethyl methyl carbonate, and dimethyl carbonate in a volume ratio of 30:50:20, and the mixture was diluted in acetone D6 to prepare a sample solution. This sample solution was then used to measure HR-LC / MS and... 1 H-NMR.

[0284] For HR-LC / MS, a ThermoFisher Orbitrap IQ-X Tribrid was used. Measurement conditions included a CapcellPak C18 column, acetonitrile and trifluoroacetic acid (100:0.02 v / v) as eluent A, and distilled water and trifluoroacetic acid (100:0.02 v / v) as eluent B; a flow rate of 1 mL / min; a UV detector set to 220 nm; and electrospray ionization (ESI) anionization mode. For 1H-NMR, a Bruker Advance Neo was used.

[0285] pass Figures 1 to 4 The existence of the compound represented by chemical formula 1-a-1 was confirmed. Specifically, according to Figure 1 The XIC (extractable ion chromatogram) with m / z 185.97140 showed a single peak at 1.35 min, confirming the presence of the compound represented by chemical formula 1-a-1 in the sample, which was then separated by LC.

[0286] According to Figure 2 In the mass spectrum, an anion corresponding to 185.97140 was observed, which corresponds to the molecular formula C2H4NO7S of the compound represented by chemical formula 1-a-1. - Consistent.

[0287] according to Figure 3Additional MS / MS analysis (tandem mass spectrometry, dual mass spectrometry) detected fragment ions at m / z 61.98818 (O3N) and 79.95725 (O3S), consistent with the expected structural decomposition pattern. These results support the presence and structural identity of the compound represented by formula 1-a-1.

[0288] according to Figure 4 of 1 The characteristic chemical shifts of 4.76 (t,2) and 4.18 (t,2) observed in the H-NMR spectrum support the presence of a compound represented by the chemical formula 1-a-1.

[0289] (2) Preparation of non-aqueous electrolytes

[0290] A non-aqueous electrolyte was prepared by dissolving LiPF6 in an organic solvent containing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) in a volume ratio of 30:50:20 to achieve a LiPF6 concentration of 1.0 M. Then, the compound represented by formula 1-a-1, vinylene carbonate (VC), fluoroethylene carbonate (FEC), and 1,3-propanesulfonyl lactone (PS) were added as additives. The contents of the compound represented by formula 1-a-1, vinylene carbonate (VC), fluoroethylene carbonate (FEC), and 1,3-propanesulfonyl lactone (PS) in the non-aqueous electrolyte were 0.80 wt%, 3.00 wt%, 1.00 wt%, and 0.10 wt%, respectively.

[0291] (3) Preparation of lithium secondary batteries

[0292] (Cathode preparation)

[0293] A positive electrode active material (LiFePO4), a conductive material (carbon nanotubes, CNTs), and a binder (polytetrafluoroethylene, PTFE) were mixed in a weight ratio of 96.0:0.5:3.5 to prepare a positive electrode active material slurry (100% by weight of solids). A 13 μm thick positive electrode current collector (Al film) was coated with the positive electrode active material slurry, dried, and rolled to prepare the positive electrode.

[0294] (Anode preparation)

[0295] A negative electrode active material (a mixture of artificial graphite and natural graphite in a weight ratio of 80:20), styrene-butadiene rubber and carboxymethyl cellulose as binders, and carbon black as a conductive material were added to distilled water as a solvent in a weight ratio of 96.7:2.8:0.5 to prepare a negative electrode active material slurry (53% by weight of solids). A 6 μm thick negative electrode current collector (Cu film) was coated with the negative electrode active material slurry, dried, and rolled to prepare the negative electrode.

[0296] Example 2

[0297] (1) Preparation of non-aqueous electrolytes

[0298] A non-aqueous electrolyte was prepared by dissolving LiPF6 in an organic solvent containing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) in a volume ratio of 30:50:20 to achieve a LiPF6 concentration of 1.0 M. Then, the compound represented by Formula 1-a-1 (prepared according to the method of Example 1), vinylene carbonate (VC), fluoroethylene carbonate (FEC), ethylene sulfate (Esa), and 1,3-propanesulfonyl lactone (PS) were added as additives. The contents of the compound represented by Formula 1-a-1, vinylene carbonate (VC), fluoroethylene carbonate (FEC), ethylene sulfate (Esa), and 1,3-propanesulfonyl lactone (PS) in the non-aqueous electrolyte were 0.30 wt%, 3.00 wt%, 1.00 wt%, 0.80 wt%, and 0.20 wt%, respectively.

[0299] (2) Preparation of lithium secondary batteries

[0300] The lithium secondary battery was prepared in the same manner as in Example 1, except that the non-aqueous electrolyte described above was used.

[0301] Example 3

[0302] (1) Preparation of non-aqueous electrolytes

[0303] A non-aqueous electrolyte was prepared by dissolving LiPF6 in an organic solvent containing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) in a volume ratio of 30:50:20 to achieve a LiPF6 concentration of 1.0 M. Then, the compound represented by chemical formula 1-a-1 (prepared according to the method of Example 1), vinylene carbonate (VC), and fluoroethylene carbonate (FEC) were added as additives. The contents of the compound represented by chemical formula 1-a-1, vinylene carbonate (VC), and fluoroethylene carbonate (FEC) in the non-aqueous electrolyte were 1.50 wt%, 3.00 wt%, and 1.00 wt%, respectively.

[0304] (2) Preparation of lithium secondary batteries

[0305] The lithium secondary battery was prepared in the same manner as in Example 1, except that the non-aqueous electrolyte described above was used.

[0306] Comparative Example 1

[0307] (1) Preparation of non-aqueous electrolytes

[0308] A non-aqueous electrolyte was prepared by dissolving LiPF6 in an organic solvent containing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) in a volume ratio of 30:50:20 to achieve a LiPF6 concentration of 1.0 M. Then, vinylene carbonate (VC), fluoroethylene carbonate (FEC), and 1,3-propanesulfonyl lactone (PS) were added as additives. The contents of vinylene carbonate (VC), fluoroethylene carbonate (FEC), and 1,3-propanesulfonyl lactone (PS) in the non-aqueous electrolyte were 3.00 wt%, 1.00 wt%, and 0.2 wt%, respectively.

[0309] (2) Preparation of lithium secondary batteries

[0310] The lithium secondary battery was prepared in the same manner as in Example 1, except that the non-aqueous electrolyte described above was used.

[0311] Comparative Example 2

[0312] (1) Preparation of non-aqueous electrolytes

[0313] A non-aqueous electrolyte was prepared by dissolving LiPF6 in an organic solvent containing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) in a volume ratio of 30:50:20 to achieve a LiPF6 concentration of 1.0 M. Then, LiNO3, vinylene carbonate (VC), and fluoroethylene carbonate (FEC) were added. The contents of LiNO3, vinylene carbonate (VC), and fluoroethylene carbonate (FEC) in the non-aqueous electrolyte were 0.25 wt%, 3.00 wt%, and 1.00 wt%, respectively.

[0314] (2) Preparation of lithium secondary batteries

[0315] The lithium secondary battery was prepared in the same manner as in Example 1, except that the non-aqueous electrolyte described above was used.

[0316] Comparative Example 3

[0317] (1) Preparation of non-aqueous electrolytes

[0318] A non-aqueous electrolyte was prepared by dissolving LiPF6 in an organic solvent containing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) in a volume ratio of 30:50:20 to achieve a LiPF6 concentration of 1.0 M. Then, ethylene sulfate (Esa), vinylene carbonate (VC), and fluoroethylene carbonate (FEC) were added. The contents of ethylene sulfate (Esa), vinylene carbonate (VC), and fluoroethylene carbonate (FEC) in the non-aqueous electrolyte were 0.50 wt%, 3.00 wt%, and 1.00 wt%, respectively.

[0319] (2) Preparation of lithium secondary batteries

[0320] The lithium secondary battery was prepared in the same manner as in Example 1, except that the non-aqueous electrolyte described above was used.

[0321] Comparative Example 4

[0322] (1) Preparation of non-aqueous electrolytes

[0323] A non-aqueous electrolyte was prepared by dissolving LiPF6 in an organic solvent containing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) in a volume ratio of 30:50:20 to achieve a LiPF6 concentration of 1.0 M. Then, the compound represented by Formula 1-a-1 (prepared according to the method of Example 1), ethylene sulfate (Esa), vinylene carbonate (VC), fluoroethylene carbonate (FEC), and 1,3-propanesulfonyl lactone (PS) were added as additives. The contents of the compound represented by Formula 1-a-1, ethylene sulfate (Esa), vinylene carbonate (VC), fluoroethylene carbonate (FEC), and 1,3-propanesulfonyl lactone (PS) were 0.20 wt%, 0.40 wt%, 3.00 wt%, 1.00 wt%, and 0.20 wt%, respectively.

[0324] (2) Preparation of lithium secondary batteries

[0325] The lithium secondary battery was prepared in the same manner as in Example 1, except that the non-aqueous electrolyte described above was used.

[0326] Comparative Example 5

[0327] (1) Preparation of non-aqueous electrolytes

[0328] A non-aqueous electrolyte was prepared by dissolving LiPF6 in an organic solvent containing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) in a volume ratio of 30:50:20 to achieve a LiPF6 concentration of 1.0 M. Then, the compound represented by Formula 1-a-1 (prepared according to the method of Example 1), ethylene sulfate (Esa), vinylene carbonate (VC), and fluoroethylene carbonate (FEC) were added as additives. The contents of the compound represented by Formula 1-a-1, ethylene sulfate (Esa), vinylene carbonate (VC), and fluoroethylene carbonate (FEC) were 1.70 wt%, 0.70 wt%, 3.00 wt%, and 1.00 wt%, respectively.

[0329] Comparative Example 6

[0330] (1) Preparation of non-aqueous electrolytes

[0331] A non-aqueous electrolyte was prepared by dissolving LiPF6 in an organic solvent containing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) in a volume ratio of 30:50:20 to achieve a LiPF6 concentration of 1.0 M. Then, the compound represented by Formula 1-a-1 (prepared according to the method of Example 1), ethylene sulfate (Esa), vinylene carbonate (VC), and fluoroethylene carbonate (FEC) were added as additives. The contents of the compound represented by Formula 1-a-1, ethylene sulfate (Esa), vinylene carbonate (VC), and fluoroethylene carbonate (FEC) were 1.40 wt%, 0.30 wt%, 3.00 wt%, and 1.00 wt%, respectively.

[0332] (2) Preparation of lithium secondary batteries

[0333] The lithium secondary battery was prepared in the same manner as in Example 1, except that the non-aqueous electrolyte described above was used.

[0334] Comparative Example 7

[0335] (1) Preparation of non-aqueous electrolytes

[0336] A non-aqueous electrolyte was prepared by dissolving LiPF6 in an organic solvent containing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) in a volume ratio of 30:50:20 to achieve a LiPF6 concentration of 1.0 M. Then, the compound represented by Formula 1-a-1 (prepared according to the method of Example 1), ethylene sulfate (Esa), vinylene carbonate (VC), fluoroethylene carbonate (FEC), and 1,3-propanesulfonyl lactone (PS) were added as additives. The contents of the compound represented by Formula 1-a-1, ethylene sulfate (Esa), vinylene carbonate (VC), fluoroethylene carbonate (FEC), and 1,3-propanesulfonyl lactone (PS) were 1.40 wt%, 0.10 wt%, 3.00 wt%, 1.00 wt%, and 0.20 wt%, respectively.

[0337] (2) Preparation of lithium secondary batteries

[0338] The lithium secondary battery was prepared in the same manner as in Example 1, except that the non-aqueous electrolyte described above was used.

[0339] Comparative Example 8

[0340] (1) Preparation of non-aqueous electrolytes

[0341] A non-aqueous electrolyte was prepared by dissolving LiPF6 in an organic solvent containing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) in a volume ratio of 30:50:20 to achieve a LiPF6 concentration of 1.0 M. Then, the compound represented by Formula 1-a-1 (prepared according to the method of Example 1), vinylene carbonate (VC), fluoroethylene carbonate (FEC), and 1,3-propanesulfonyl lactone (PS) were added as additives. The contents of the compound represented by Formula 1-a-1, vinylene carbonate (VC), fluoroethylene carbonate (FEC), and 1,3-propanesulfonyl lactone (PS) in the non-aqueous electrolyte were 0.30 wt%, 3.00 wt%, 1.00 wt%, and 1.50 wt%, respectively.

[0342] (2) Preparation of lithium secondary batteries

[0343] The lithium secondary battery was prepared in the same manner as in Example 1, except that the non-aqueous electrolyte described above was used.

[0344] Comparative Example 9

[0345] (1) Preparation of non-aqueous electrolytes

[0346] A non-aqueous electrolyte was prepared by dissolving LiPF6 in an organic solvent containing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) in a volume ratio of 30:50:20 to achieve a LiPF6 concentration of 1.0 M. Then, the compound represented by Formula 1-a-1 (prepared according to the method of Example 1), ethylene sulfate (Esa), vinylene carbonate (VC), and fluoroethylene carbonate (FEC) were added as additives. The contents of the compound represented by Formula 1-a-1, ethylene sulfate (Esa), vinylene carbonate (VC), and fluoroethylene carbonate (FEC) were 0.30 wt%, 1.50 wt%, 3.00 wt%, and 1.00 wt%, respectively.

[0347] (2) Preparation of lithium secondary batteries

[0348] The lithium secondary battery was prepared in the same manner as in Example 1, except that the non-aqueous electrolyte described above was used.

[0349] Comparative Example 10

[0350] (1) Preparation of non-aqueous electrolytes

[0351] A non-aqueous electrolyte was prepared by dissolving LiPF6 in an organic solvent containing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) in a volume ratio of 30:50:20 to achieve a LiPF6 concentration of 1.0 M. Then, the compound represented by Formula 1-a-1 (prepared according to the method of Example 1), vinylene carbonate (VC), fluoroethylene carbonate (FEC), and 1,3-propanesulfonyl lactone (PS) were added as additives. The contents of the compound represented by Formula 1-a-1, vinylene carbonate (VC), fluoroethylene carbonate (FEC), and 1,3-propanesulfonyl lactone (PS) were 0.70 wt%, 3.00 wt%, 1.00 wt%, and 1.00 wt%, respectively.

[0352] (2) Preparation of lithium secondary batteries

[0353] The lithium secondary battery was prepared in the same manner as in Example 1, except that the non-aqueous electrolyte described above was used.

[0354] Comparative Example 11

[0355] (1) Preparation of non-aqueous electrolytes

[0356] A non-aqueous electrolyte was prepared by dissolving LiPF6 in an organic solvent containing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) in a volume ratio of 30:50:20 to achieve a LiPF6 concentration of 1.0 M. Then, the compound represented by Formula 1-a-1 (prepared according to the method of Example 1), ethylene sulfate (Esa), vinylene carbonate (VC), and fluoroethylene carbonate (FEC) were added as additives. The contents of the compound represented by Formula 1-a-1, ethylene sulfate (Esa), vinylene carbonate (VC), and fluoroethylene carbonate (FEC) were 0.70 wt%, 1.00 wt%, 3.00 wt%, and 1.00 wt%, respectively.

[0357] (2) Preparation of lithium secondary batteries

[0358] The lithium secondary battery was prepared in the same manner as in Example 1, except that the non-aqueous electrolyte described above was used.

[0359] Table 1

[0360] Experimental Example: High-Temperature Cycling Performance Evaluation

[0361] The high-temperature cycling performance of the lithium secondary batteries prepared in the above-described examples and comparative examples was evaluated.

[0362] Specifically, the lithium secondary batteries of the examples and comparative examples were charged to 3.8V (0.05C cutoff) at 0.33C under CC-CV conditions at 45°C, and then discharged to 2.5V at 0.33C under CC conditions. This was defined as one cycle. The discharge capacity after one cycle was measured.

[0363] Subsequently, after 300 charge-discharge cycles under the above-described charge-discharge conditions, the capacity retention rate (%) was measured. The capacity retention rate (%) was calculated using the following mathematical formula. The results are shown below. Figure 5 And in Table 2 below.

[0364] Capacity retention (%) = (Discharge capacity after 300 cycles / Discharge capacity after 1 cycle) × 100

[0365] Table 2

[0366] Refer to Table 2 and Figure 5 The lithium secondary batteries of the examples that contain compounds represented by Formula 1 within the above-mentioned range and specify the content range of compounds represented by Formula 1, ethylene sulfate, and 1,3-propanesulfonyl lactone exhibit significantly superior cycle performance compared to the comparative examples.

Claims

1. A non-aqueous electrolyte comprising a lithium salt, an organic solvent, and additives. in, The additive contains a compound represented by chemical formula 1. The additive comprises at least one of the compound represented by Formula 1, ethylene sulfate, and 1,3-propanesulfonyl lactone. The compound represented by chemical formula 1 is present in a concentration of 0.25% to 1.60% by weight in the non-aqueous electrolyte, and Based on the total weight of the non-aqueous electrolyte, the total content of the compound represented by Formula 1, ethylene sulfate, and 1,3-propanesulfonyl lactone is from 0.25% to 1.60% by weight. [Chemical Formula 1] In chemical formula 1, R1 is -O-NO2. L1 is an alkyleneoxy group having 1 to 5 carbon atoms. M is a metal cation or an organic cation. When M is a metal cation, a is the valence of M; when M is an organic cation, a is 1. a=b.

2. The non-aqueous electrolyte as described in claim 1, in, M is a metal cation, and M is selected from any one of the group consisting of Li, K, Ca, Mg, and Cs.

3. The non-aqueous electrolyte as described in claim 1, in, M is an organic cation, and M is any one of the groups selected from compounds represented by chemical formulas M-1 to M-6: [Chemical Formula M-1] In chemical formula M-1, X M1 -N(R) M15 )- or -S-, and R M11 R M12 R M13 R M14 and R M15 Each of the following is independently hydrogen, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, a cyanoalkyl group having 2 to 12 carbon atoms, an alkoxyalkyl group having 2 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. [Chemical formula M-2] In chemical formula M-2, X M2 -N(R) M25 )- or -S-, and R M21 R M22 R M23 R M24 and R M25 Each of the following is independently hydrogen, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, a cyanoalkyl group having 2 to 12 carbon atoms, an alkoxyalkyl group having 2 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. [Chemical Formula M-3] In chemical formula M-3, R M31 R M32 R M33 R M34 R M35 and R M36 Each of the following is independently hydrogen, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, a cyanoalkyl group having 2 to 12 carbon atoms, an alkoxyalkyl group having 2 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. [Chemical formula M-4] In chemical formula M-4, R M41 R M42 R M43 and R M44 Each of the following is independently hydrogen, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, a cyanoalkyl group having 2 to 12 carbon atoms, an alkoxyalkyl group having 2 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms, and R M41 R M42 R M43 and R M44 At least two of them are alkyl groups having 1 to 5 carbon atoms, and can bond together to form an aliphatic hydrocarbon ring. [Chemical Formula M-5] In chemical formula M-5, R M51 R M52 R M53 and R M54 Each of the following is independently hydrogen, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, a cyanoalkyl group having 2 to 12 carbon atoms, an alkoxyalkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms, and R M51 R M52 R M53 and R M54 At least two of them can bond with each other to form an aliphatic hydrocarbon ring. [Chemical Formula M-6] In chemical formula M-6, R M61 R M62 and R M63 Each of the following is independently hydrogen, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, a cyanoethyl group having 1 to 12 carbon atoms, an alkoxyalkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms, and R M61 R M62 and R M63 At least two of them can bond with each other to form an aliphatic hydrocarbon ring.

4. The non-aqueous electrolyte as described in claim 1, in, The compound represented by chemical formula 1 includes the compound represented by chemical formula 1-A: [Chemical Formula 1-A] In chemical formula 1-A, M, a, b, and R1 are each as defined in chemical formula 1.

5. The non-aqueous electrolyte as described in claim 1, in, The compound represented by chemical formula 1 includes the compound represented by chemical formula 1-A-1: [Chemical Formula 1-A-1] In chemical formula 1-A-1, M, a, and b are each as defined in chemical formula 1.

6. The non-aqueous electrolyte as described in claim 1, in, The compound represented by chemical formula 1 includes the compound represented by chemical formula 1-a-1: [Chemical Formula 1-a-1] 。 7. The non-aqueous electrolyte as described in claim 1, in, Based on the total weight of the non-aqueous electrolyte, the total content of the compound represented by Formula 1, ethylene sulfate, and 1,3-propanesulfonyl lactone is from 0.75% to 1.60% by weight.

8. The non-aqueous electrolyte as described in claim 1, in, The additive also includes at least one auxiliary additive selected from the group consisting of cyclic carbonates, nitriles, benzenes, lithium salts, amines, and silanes.

9. The non-aqueous electrolyte as described in claim 1, in, The organic solvents include carbonate organic solvents.

10. The non-aqueous electrolyte as described in claim 9, in, The carbonate organic solvents include cyclic carbonate organic solvents and linear carbonate organic solvents.

11. A lithium secondary battery, comprising: positive electrode; The negative electrode opposite to the positive electrode; The membrane sandwiched between the negative electrode and the positive electrode; and The non-aqueous electrolyte according to claim 1.

12. The lithium secondary battery as described in claim 11, in, The negative electrode contains a negative electrode active material, and The negative electrode active material comprises at least one selected from carbon-based active materials and silicon-based active materials.

13. The lithium secondary battery as described in claim 11, in, The positive electrode contains a positive electrode active material, and The positive electrode active material includes lithium iron phosphate.

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