Secondary battery electrolyte additive, lithium secondary battery non-aqueous electrolyte comprising same, and lithium secondary battery

Abstract

The present invention relates to a lithium secondary battery electrolyte additive, a lithium secondary battery non-aqueous electrolyte comprising same, and a lithium secondary battery. The lithium secondary battery electrolyte additive may comprise a compound represented by chemical formula 1.

Description

Electrolyte additive for secondary batteries, non-aqueous electrolyte for lithium secondary batteries containing the same, and lithium secondary batteries Cross-citation with related application(s) This application claims the benefit of priority to Korean Patent Application No. 10-2023-0115746, filed August 31, 2023, the entire contents of which are incorporated herein by reference. Technology field The present invention relates to an electrolyte additive for a secondary battery, a non-aqueous electrolyte for a lithium secondary battery containing the same, and a lithium secondary battery, and more particularly, to an electrolyte additive for a secondary battery having an excellent effect of removing decomposition products generated from a lithium salt, and a non-aqueous electrolyte for a lithium secondary battery containing the same and a lithium secondary battery. As dependence on electric energy in modern society increases, renewable energy generation that can increase production without causing environmental problems is emerging as a next-generation power generation system. Because these renewable energies exhibit intermittent power generation characteristics, large-capacity power storage devices are essential to ensure a stable power supply. Among these power storage devices, lithium-ion batteries are gaining attention as the commercially available devices with the highest energy density. The above lithium ion battery is composed of a positive electrode made of a transition metal oxide containing lithium, a negative electrode capable of storing lithium, an electrolyte including a non-aqueous organic solvent containing a lithium salt, and a separator, and the lithium salt is mainly LiPF6. However, since the LiPF6 is very vulnerable to heat, when the battery is exposed to high temperatures, it thermally decomposes and generates Lewis acids such as PF5. These Lewis acids not only cause decomposition reactions of non-aqueous organic solvents such as ethylene carbonate, but also deteriorate passivation films such as the solid electrolyte interphase (SEI) formed on the electrode surface, resulting in additional electrolyte decomposition, increased resistance, and the elution of transition metals from the positive electrode. In addition, the eluted transition metal ions can increase the resistance of the positive electrode as they are redeposited on the positive electrode, and conversely, they can move to the negative electrode through the electrolyte and be deposited on the negative electrode, causing self-discharge of the negative electrode, or cause destruction and regeneration of the solid electrolyte interphase, which additionally consumes lithium ions, causing increased resistance and a deterioration of the lifespan. Therefore, in order to suppress the deterioration behavior of the battery when the battery is exposed to high temperatures, a method is required that can suppress additional electrolyte decomposition reactions by reducing SEI deterioration caused by byproducts such as HF and PF5 generated by thermal decomposition of lithium salts. The present invention is intended to solve the above problems, and to provide an electrolyte additive for a secondary battery that can remove decomposition products generated from lithium salts and at the same time form a strong passive film on the surfaces of positive and negative electrodes. In addition, the present invention aims to provide a non-aqueous electrolyte for a lithium secondary battery capable of realizing excellent high-temperature stability and high-temperature cycle characteristics by including the electrolyte additive for a secondary battery, and a lithium secondary battery including the same. [1] The present invention provides an electrolyte additive for a secondary battery comprising a compound represented by the following chemical formula 1: [Chemical Formula 1] In the above chemical formula 1, Ra is an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, -(R)n-R0 (R is oxygen or an alkylene group having 1 to 3 carbon atoms, R0 is an aryl group having 6 to 10 carbon atoms, and n is at least one integer from 0 to 5), or -R1-O-R2 (R1 is an alkylene group having 1 to 3 carbon atoms, and R2 is an aryl group having 6 to 10 carbon atoms), Rb, Rc and Rd are each independently hydrogen or an alkyl group having 1 to 10 carbon atoms. [2] The present invention provides an electrolyte additive for a secondary battery, wherein in the above [1], the alkyl group or alkoxy group is substituted with an alkyl group having 1 to 3 carbon atoms or at least one fluorine. [3] The present invention provides an electrolyte additive for a secondary battery, wherein in the chemical formula 1 of [1] or [2], Ra is an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, -(R)n-R0 (R is oxygen or an alkylene group having 1 to 3 carbon atoms, R0 is an aryl group having 6 to 8 carbon atoms, and n is at least one integer from 0 to 3), or -R1-O-R2 (R1 is an alkylene group having 1 to 3 carbon atoms, and R2 is an aryl group having 6 to 8 carbon atoms), and Rb, Rc, and Rd are each independently hydrogen or an alkyl group having 1 to 8 carbon atoms. [4] The present invention provides an electrolyte additive for a secondary battery, wherein in at least one of the above [1] to [3], in the chemical formula 1, Ra is an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, -(R)n-R0 (R is oxygen or an alkylene group having 1 to 3 carbon atoms, R0 is an aryl group having 6 to 8 carbon atoms, and n is an integer of 0 or 1), and Rb, Rc, and Rd are each independently hydrogen or an alkyl group having 1 to 5 carbon atoms. [5] The present invention provides an electrolyte additive for a secondary battery, wherein in at least one of the above [1] to [4], in the chemical formula 1, Ra is an alkyl group having 1 to 3 carbon atoms or -(R)n-R0 (R is oxygen or an alkylene group having 1 to 3 carbon atoms, R0 is an aryl group having 6 to 8 carbon atoms, and n is an integer of 0 or 1), and Rb, Rc, and Rd are each independently an alkyl group having 1 to 3 carbon atoms. [6] The present invention provides an electrolyte additive for a secondary battery, wherein in at least one of the above [1] to [5], the compound represented by the chemical formula 1 is at least one selected from the group consisting of compounds represented by the following chemical formulas 1A to 1D. [Chemical Formula 1A] [Chemical Formula 1B] [Chemical Formula 1C] [Chemical Formula 1D] [7] The present invention provides a non-aqueous electrolyte for a lithium secondary battery comprising the electrolyte additive for a secondary battery of the above [1]. [8] The present invention provides a non-aqueous electrolyte for a lithium secondary battery, wherein the electrolyte additive for a secondary battery is included in an amount of 0.1 wt% to 10.0 wt% based on the total weight of the non-aqueous electrolyte for a lithium secondary battery in the above [7]. [9] The present invention provides a non-aqueous electrolyte for a lithium secondary battery, wherein the non-aqueous electrolyte for a lithium secondary battery in the above [7] or [8] further includes a lithium salt and a non-aqueous organic solvent.

[0010] The present invention provides a non-aqueous electrolyte for a lithium secondary battery, wherein in at least one of the above [7] to [9], the non-aqueous electrolyte for a lithium secondary battery further comprises at least one other additive selected from the group consisting of a carbonate compound, a sultone compound, a sulfate compound, a phosphate or phosphite compound, a borate compound, a nitrile compound, an amine compound, a silane compound, and a lithium salt compound, which are substituted or unsubstituted with a halogen.

[0011] The present invention provides a lithium secondary battery comprising: a positive electrode including a positive electrode active material; a negative electrode including a negative electrode active material; a separator interposed between the negative electrode and the positive electrode; and a non-aqueous electrolyte for a lithium secondary battery of the above [7]. The non-aqueous electrolyte for a lithium secondary battery of the present invention comprises a compound represented by chemical formula 1, which includes an isocyanate unit in its molecular structure and a nitrogen atom in the cationic portion that can act as a Lewis base, as an electrolyte additive, thereby effectively removing (scavenging) Lewis acid generated as a decomposition product of a lithium salt and forming a more stable SEI film on the surface of an anode. Therefore, by applying the non-aqueous electrolyte for a lithium secondary battery of the present invention, a stable film is formed on the surfaces of the positive and negative electrodes, effectively suppressing the elution of transition metals from the positive electrode, and at the same time, by removing by-products generated due to thermal decomposition of lithium salt, it is possible to reduce SEI film deterioration, thereby realizing a lithium secondary battery with improved high-temperature durability, such as high-temperature storage characteristics and high-temperature cycle characteristics. The following drawings attached to this specification illustrate preferred embodiments of the present invention, and serve to further understand the technical idea of ​​the present invention together with the contents of the invention described above, and therefore the present invention should not be interpreted as being limited to matters described in such drawings. Figure 1 is an NMR graph of the compound prepared in Example 1. Figure 2 is an NMR graph of the compound prepared in Example 2. First, before describing the present invention, the terms and words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, and should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention based on the principle that the inventor can appropriately define the concept of the term in order to explain his or her own invention in the best way. Meanwhile, the terms used in this specification are used merely to describe exemplary embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, it should be understood that the terms “include,” “comprising,” or “having” are intended to specify the presence of a feature, number, step, component, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, components, or combinations thereof. In this specification, “%” means weight percent unless explicitly indicated otherwise. Before explaining the present invention, in the description of "carbon number a to b" in the specification, "a" and "b" refer to the number of carbon atoms included in a specific functional group. That is, the functional group may include "a" to "b" carbon atoms. In addition, in this specification, unless otherwise defined, "substitution" means that at least one hydrogen bonded to carbon is replaced with an element other than hydrogen, for example, it means that it is replaced with an alkyl group having 1 to 5 carbon atoms or a fluorine element. In general, lithium secondary batteries can secure high-temperature storage characteristics by forming a passive film on the surfaces of the positive and negative electrodes as the non-aqueous electrolyte decomposes during the initial charge and discharge. However, the film can be degraded by Lewis acids such as HF and PF5, which are generated by the thermal decomposition of lithium salts (such as LiPF6) widely used in lithium-ion batteries. That is, when transition metal ions are eluted from the positive electrode due to attack by Lewis acids, the surface structure changes, increasing the surface resistance of the electrode. As the metal ions serving as redox centers are lost, the theoretical capacity decreases, and the expressed capacity may decrease. In addition, the eluted transition metal ions are deposited on the negative electrode where they react in a strong reduction potential band, consuming electrons. In addition, they can destroy the film during deposition, exposing the negative electrode surface, which can cause additional non-aqueous electrolyte decomposition reactions. As a result, there is a problem in which the negative electrode resistance and irreversible capacity increase, and the capacity of the cell continuously decreases. Accordingly, the present invention aims to provide an electrolyte additive for a lithium secondary battery capable of removing decomposition products generated from a lithium salt and forming a strong passive film on the surfaces of a positive and negative electrodes, a non-aqueous electrolyte for a lithium secondary battery containing the additive, and a lithium secondary battery. Hereinafter, the present invention will be described in detail. The electrolyte additive for a secondary battery according to the present invention, the non-aqueous electrolyte for a lithium secondary battery including the same, and the lithium secondary battery comprise at least one of the following disclosed configurations, and may comprise any combination between technically possible configurations among the following configurations. Electrolyte additives for secondary batteries The present invention provides an electrolyte additive for a secondary battery comprising a compound represented by the following chemical formula 1. [Chemical Formula 1] In the above chemical formula 1, Ra is an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, -(R)n-R0 (R is oxygen or an alkylene group having 1 to 3 carbon atoms, R0 is an aryl group having 6 to 10 carbon atoms, and n is at least one integer from 0 to 5), or -R1-O-R2 (R1 is an alkylene group having 1 to 3 carbon atoms, and R2 is an aryl group having 6 to 10 carbon atoms), Rb, Rc and Rd are each independently hydrogen or an alkyl group having 1 to 10 carbon atoms. At this time, the alkyl group or alkoxy group may be substituted with an alkyl group having 1 to 3 carbon atoms or at least one fluorine. Meanwhile, in the above chemical formula 1, Ra is an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, -(R)n-R0 (R is oxygen or an alkylene group having 1 to 3 carbon atoms, R0 is an aryl group having 6 to 8 carbon atoms, and n is at least one integer from 0 to 3), or -R1-O-R2 (R1 is an alkylene group having 1 to 3 carbon atoms, and R2 is an aryl group having 6 to 8 carbon atoms), and Rb, Rc, and Rd may each independently be hydrogen or an alkyl group having 1 to 8 carbon atoms. In addition, in the above chemical formula 1, Ra is an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, -(R)n-R0 (R is oxygen or an alkylene group having 1 to 3 carbon atoms, R0 is an aryl group having 6 to 8 carbon atoms, and n is an integer of 0 or 1), and Rb, Rc, and Rd may each independently be hydrogen or an alkyl group having 1 to 5 carbon atoms. Alternatively, in the above chemical formula 1, Ra is an alkyl group having 1 to 3 carbon atoms or -(R)n-R0 (R is oxygen or an alkylene group having 1 to 3 carbon atoms, R0 is an aryl group having 6 to 8 carbon atoms, and n is an integer of 0 or 1), and Rb, Rc, and Rd may each independently be an alkyl group having 1 to 3 carbon atoms. Specifically, the compound represented by the above chemical formula 1 may be at least one selected from the group consisting of compounds represented by the following chemical formulas A to 1D. [Chemical Formula 1A] [Chemical Formula 1B] [Chemical Formula 1C] [Chemical Formula 1D] . The compound represented by the above chemical formula 1 is an organic salt-type compound, and can be easily dissolved in major non-aqueous electrolyte solvents such as ethylene carbonate, propylene carbonate, dimethyl carbonate, or diethyl carbonate, which will be described later, and thus a uniform non-aqueous electrolyte can be prepared. In particular, according to the following reaction scheme 1, the compound represented by the above chemical formula 1 can be decomposed into a compound including an isocyanate unit and a compound including an amino alcohol unit by Curtius rearrangement when a specific temperature of 50°C or higher and pressure are applied. At this time, the nitrogen atom having an unshared electron pair included in the molecular structure of the decomposed compound acts as a Lewis base, forming high bonding energy with a Lewis acid substance generated as a decomposition product of the lithium salt, thereby easily scavenging the decomposition product of the lithium salt, etc. In addition, the compound including the isocyanate unit can form a durable film (SEI) based on nitrogen (N) atoms that is not easily decomposed and can be maintained when the battery is exposed to high temperatures through a reaction site where a phenol group or a carbonyl group is formed when the negative electrode surface is partially oxidized. In addition, the compound including the amino alcohol unit can in-situ trap HF generated by an acid-base reaction with a decomposition product of a lithium salt such as HF, and suppresses the generation of HF thereby preventing damage to the film, thereby suppressing metal elution from the positive or negative electrode. [Reaction Formula 1] Non-aqueous electrolyte for lithium secondary batteries In addition, according to the present invention, a non-aqueous electrolyte for a lithium secondary battery is provided, which includes the electrolyte additive for a secondary battery. (1) Electrolyte additive for secondary batteries The non-aqueous electrolyte for a lithium secondary battery of the present invention may include an electrolyte additive for a secondary battery including a compound represented by the above chemical formula 1. In this case, since the description of the compound overlaps with the above-described content, the description thereof is omitted. Meanwhile, the content of the secondary battery electrolyte additive may be included in an amount of 10.0 wt% or less, specifically 0.1 wt% to 8.0 wt%, based on the total weight of the non-aqueous electrolyte, taking into account the effect of forming a stable film on the electrode surface and the effect of removing thermal decomposition products of lithium salts. When the above secondary battery electrolyte additive is included within the above content range, it is possible to form a strong film on the surface of the positive electrode while suppressing as much as possible the side effects of the additive, such as side reactions, capacity reduction, and increased resistance, and effectively suppressing the elution of transition metals from the positive electrode active material at high temperatures, and effectively removing thermal decomposition products of lithium salts, thereby realizing excellent high-temperature durability. That is, when the content of the secondary battery electrolyte additive is 0.1 wt% or more, the effect of removing thermal decomposition products of lithium salts can be maintained even when the operating time increases, and a stable film can be formed on the electrode surface to further improve the effect of inhibiting transition metal dissolution, etc. In addition, when the content of the secondary battery electrolyte additive is 8.0 wt% or less, side reactions caused by additives included in a relatively large amount can be inhibited. Specifically, the secondary battery electrolyte additive may be included in an amount of 0.1 wt% to 5.0 wt%, specifically 0.1 wt% to 4.0 wt%, and preferably 0.3 wt% to 3.0 wt%, based on the total weight of the non-aqueous electrolyte. As described above, the non-aqueous electrolyte of the present invention includes an electrolyte additive for a secondary battery including a compound represented by the above chemical formula 1, thereby forming a more robust passive film at the interface between the electrode and the electrolyte, thereby controlling the cathode reduction reaction of additional transition metals due to SEI decomposition, and preventing transition metals eluted during high-temperature storage from being deposited on the cathode. Therefore, when using a high-content nickel positive electrode active material, side reactions can be suppressed, thereby manufacturing a lithium secondary battery having improved initial performance as well as high-temperature durability and long-term lifespan. In addition, the non-aqueous electrolyte for a lithium secondary battery of the present invention may further include a lithium salt and a non-aqueous organic solvent. (2) Lithium salt The above lithium salt can be used without limitation as an electrolyte for lithium secondary batteries, for example, Li as a cation. + , and the anion is F - , Cl - , Br - , I - , NO3 - , N(CN)2 - , BF4 - , ClO4 - , B 10 Cl 10 - , AlCl4 - , AlO2 - , PF6 - , CF3SO3 - , CH3CO2 - , CF3CO2 - , AsF6 - , SbF6 - , CH3SO3 - , (CF3CF2SO2)2N - , (CF3SO2)2N - , (FSO2)2N - , BF2C2O4 - , BC4O8 - , PF4C2O4 - , PF2C4O8 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , C4F9SO3 - , CF3CF2SO3 - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , CF3(CF2)7SO3 - and SCN -At least one selected from the group consisting of Specifically, the lithium salt is LiCl, LiBr, LiI, LiBF4, LiClO4, LiB 10 Cl 10 , LiAlCl4, LiAlO2, LiPF6, LiCF3SO3, LiCH3CO2, LiCF3CO2, LiAsF6, LiSbF6, LiCH3SO3, LiN(SO2F)2(lithium bis(fluorosulfonyl)imide, LiFSI), LiN(SO2CF2CF3)2(lithium bis(pentafluoroethane sulfonyl) imide, LiBETI), and LiN(SO2CF3)2(lithium bis(trifluoromethane sulfonyl) imide, LiTFSI). In addition to these, lithium salts commonly used in electrolytes of lithium secondary batteries can be used without limitation. The above lithium salt can be appropriately changed within a commonly usable range, but in order to obtain an optimal effect of forming a film for preventing corrosion on the electrode surface, it can be included in the electrolyte at a concentration of 0.8 M to 4.0 M, specifically, at a concentration of 1.0 M to 3.0 M. When the lithium salt satisfies the above concentration range, the mobility of lithium ions can be improved, thereby improving low-temperature output characteristics and cycle characteristics during high-temperature storage, and the viscosity of the non-aqueous electrolyte can be controlled to implement optimal impregnation properties. (3) Non-aqueous organic solvent Additionally, the description of non-aqueous organic solvents is as follows. As the above non-aqueous organic solvent, various organic solvents commonly used in non-aqueous electrolytes can be used without limitation. There is no limitation on the type of the solvent as long as it can minimize decomposition due to oxidation reactions, etc. during the charge / discharge process of the secondary battery and can exhibit the desired characteristics together with additives. Specifically, the non-aqueous organic solvent may include a cyclic carbonate-based organic solvent, a linear carbonate-based organic solvent, or a mixed organic solvent thereof. The above cyclic carbonate-based organic solvent is a high-viscosity organic solvent that has a high dielectric constant and thus easily dissociates a lithium salt in a non-aqueous electrolyte. As a specific example, the organic solvent may include at least one non-aqueous organic solvent selected from the group consisting of ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate, and vinylene carbonate, and among these, the organic solvent may include ethylene carbonate. The linear carbonate-based organic solvent is an organic solvent having low viscosity and low dielectric constant, and may include at least one non-aqueous organic solvent selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, ethylmethyl carbonate (EMC), methylpropyl carbonate, and ethylpropyl carbonate, and may specifically include dimethyl carbonate (DMC) or ethylmethyl carbonate (EMC). The non-aqueous organic solvent of the present invention can be used by mixing the cyclic carbonate non-aqueous organic solvent and the linear carbonate non-aqueous organic solvent. In this case, the cyclic carbonate non-aqueous organic solvent and the linear carbonate non-aqueous organic solvent can be used by mixing them in a volume ratio of 10:90 to 50:50, specifically, a volume ratio of 20:80 to 30:70. In addition, the non-aqueous organic solvent may additionally include a linear ester-based non-aqueous organic solvent and / or a cyclic ester-based non-aqueous organic solvent having a low melting point and high stability at high temperatures, in order to produce an electrolyte having high ionic conductivity. Representative examples of the linear ester-based non-aqueous organic solvent include at least one non-aqueous organic solvent selected from the group consisting of methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, and butyl propionate. In addition, the cyclic ester-based non-aqueous organic solvent may include at least one non-aqueous organic solvent selected from the group consisting of γ-butyrolactone, γ-valerolactone, γ-caprolactone, σ-valerolactone, and ε-caprolactone. Meanwhile, the remainder of the non-aqueous electrolyte of the present invention, excluding the non-aqueous organic solvent, such as the electrolyte additive for the secondary battery of the present invention and the lithium salt, may all be non-aqueous organic solvents unless otherwise stated. Meanwhile, the non-aqueous electrolyte for a lithium secondary battery of the present invention may further include other additives described below as needed to prevent the non-aqueous electrolyte from being decomposed in a high-power environment and causing cathode collapse, or to further improve battery characteristics such as low-temperature high-rate discharge characteristics, high-temperature stability, overcharge prevention, and high-temperature battery expansion suppression effect. (4) Other additives The above-mentioned other additives may include at least one selected from the group consisting of carbonate compounds, sultone compounds, sulfate compounds, phosphate or phosphite compounds, borate compounds, nitrile compounds, amine compounds, silane compounds, and lithium salt compounds substituted or unsubstituted with halogen, and more specifically, carbonate compounds substituted or unsubstituted with halogen may be included. Representative examples of the above halogen-substituted or unsubstituted carbonate compounds include vinylene carbonate (VC), vinylethylene carbonate, or fluoroethylene carbonate (FEC). The above sultone compound may be at least one compound selected from the group consisting of 1,3-propane sultone (PS), 1,4-butane sultone, ethene sultone, and 1,3-propene sultone (PRS). The above sulfate compound may be, for example, ethylene sulfate (Esa), trimethylene sulfate (TMS), or methyl trimethylene sulfate (MTMS). The above phosphate or phosphite compound may be at least one compound selected from the group consisting of lithium difluoro(bisoxalato)phosphate, lithium difluorophosphate, tris(trimethylsilyl) phosphite, and tris(2,2,2-trifluoroethyl) phosphate. The above borate compound may be tetraphenylborate, lithium oxalyldifluoroborate (LiODFB), or lithium bisoxalatoborate (LiB(C2O4)2; LiBOB). The nitrile compound may be, for example, at least one compound selected from the group consisting of succinonitrile, adiponitrile, acetonitrile, propionitrile, butyronitrile, valeronitrile, caprylonitrile, heptanenitrile, cyclopentane carbonitrile, cyclohexane carbonitrile, 2-fluorobenzonitrile, 4-fluorobenzonitrile, difluorobenzonitrile, trifluorobenzonitrile, phenylacetonitrile, 2-fluorophenylacetonitrile, and 4-fluorophenylacetonitrile. The above lithium salt compound is a compound different from the lithium salt included in the non-aqueous electrolyte, and may include LiPO2F2 or LiBF4. The above-mentioned other additives may be used by mixing two or more compounds, and may be included in an amount of 0.01 to 10 wt%, specifically 0.05 to 7 wt%, and preferably 0.1 to 5 wt%, based on the total weight of the non-aqueous electrolyte. When the above-mentioned other additives are included within the above content range, the effects of improving the low-temperature output characteristics, high-temperature storage characteristics, and high-temperature lifespan characteristics of the secondary battery can be obtained, and side reactions of the battery due to excessive additives can be prevented. In addition, the above-mentioned other additives can be prevented from being sufficiently decomposed at high temperatures, thereby preventing unreacted substances from being generated or precipitated in the electrolyte at room temperature. lithium secondary battery Next, a lithium secondary battery according to the present invention will be described. A lithium secondary battery according to the present invention comprises a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and a non-aqueous electrolyte. The non-aqueous electrolyte may comprise the non-aqueous electrolyte according to the present invention. Since the non-aqueous electrolyte has been described above, its description will be omitted, and other components will be described below. (1) Bipolar The positive electrode according to the present invention may include a positive electrode active material layer including a positive electrode active material. The above positive electrode active material is a compound capable of reversible intercalation and deintercalation of lithium, and specifically, may include a lithium composite metal oxide represented by the following chemical formula 2, which includes lithium and at least one metal selected from the group consisting of nickel (Ni), cobalt (Co), manganese (Mn), and aluminum (Al). [Chemical Formula 2] Li 1+a Ni x Co y M 1 z M 2 w O2 In the above chemical formula 2, M 1 is Mn, Al or a combination thereof, M 2 is at least one selected from the group consisting of Al, Zr, W, Ti, Mg, Ca and Sr, and 0≤a≤0.5, 0.55 <x<1.0, 0<y≤0.4, 0<z≤0.4, 0≤w≤0.1 이다. The above 1+a represents the atomic fraction of lithium in the lithium composite metal oxide, and may be 0≤a≤0.5, preferably 0≤a≤0.2, and more preferably 0≤a≤0.1. When the molar ratio of lithium satisfies the above range, the crystal structure of the lithium-nickel-cobalt-transition metal (M) oxide can be stably formed. The above x represents the molar ratio of nickel among all metals excluding lithium in the lithium composite metal oxide, and is specifically 0.55. <x<1.0, 더욱 구체적으로는 0.6≤x≤0.98, 보다 더 구체적으로는 0.6≤x≤0.95일 수 있다. 니켈의 몰비가 상기 범위를 만족할 때, 높은 에너지 밀도를 나타내어 고용량 구현이 가능하다. The above y represents the atomic fraction of cobalt among all metals excluding lithium in the oxide of lithium composite metal, and is 0. <y≤0.4, 구체적으로 0<y≤0.3, 더욱 구체적으로는 0.05≤y≤0.3일 수 있다. 코발트의 몰비가 상기 범위를 만족할 때, 양호한 저항 특성 및 출력 특성을 구현할 수 있다. The above z is M of all metals except lithium in the oxide of lithium composite metal. 1 It represents the molar ratio of elements, 0 <z≤0.4, 바람직하게는 0<z≤0.3, 더 바람직하게는 0.01≤z≤0.3일 수 있다. M 1 When the molar ratio of the elements satisfies the above range, the structural stability of the positive electrode active material is excellent. The above w is M of all metals except lithium in the oxide of lithium composite metal.2 It represents the molar ratio of elements, 0 <w≤0.1, 바람직하게는 0<w≤0.05, 더 바람직하게는 0<w≤0.02이다. Specifically, the positive electrode active material is Li(Ni) having a Ni content of 0.55 atm% or more in order to realize a high-capacity battery. 0.6 Mn 0.2 Co 0.2 )O2, Li(Ni) 0.7 Mn 0.2 Co 0.1 )O2, Li(Ni 0.8 Mn 0.1 Co 0.1 )O2, Li(Ni 0.8 Co 0.15 Al 0.05 )O2, Li(Ni 0.86 Mn 0.07 Co 0.05 Al 0.02 )O2 or Li(Ni 0.90 Mn 0.05 Co 0.05 ) It is preferable to include a lithium composite transition metal oxide such as O2. Meanwhile, in the case of the high-content Ni-lithium composite metal oxide, when exposed to high temperatures or the like after charge / discharge, the structural collapse of the positive electrode causes transition metal ions to be eluted, which causes side reactions. For example, nickel ions (Ni) contained in high-content Ni lithium composite metal oxide 2+ ) exists in a stable nickel ion form before charge and discharge, and as the oxidation number increases after charge and discharge, Ni 3+ ion or Ni 4+ It changes into an ion. Stable Ni 2+ Unlike ions, Ni 3+ ions or Ni 4+ The ion undergoes rapid oxygen desorption due to its instability, resulting in Ni 2+can be reduced to . At this time, the desorbed oxygen reacts with the electrolyte to change the surface properties of the electrode or increase the charge transfer impedance of the surface, which causes a decrease in capacity or high-rate characteristics, thereby lowering the energy density. This phenomenon is more severe on the surface of the anode containing a high Ni content. In addition, if the structure of the anode collapses due to high temperature exposure, etc., Ni is released from the anode. 2+ Cations are dissolved into the electrolyte, and the dissolved Ni 2+ Cations react with the negative electrode's passive film (SEI), decomposing it. As a result, some of the negative electrode active material is exposed to the electrolyte, which can lead to side reactions that can lead to decreased capacity and cycle life, as well as increased resistance. These problems can be exacerbated by the presence of large amounts of HF or other substances in the electrolyte. Therefore, in order to solve these various problems, it is very important to form a strong film on the surface of a high-Ni content anode that can prevent side reactions with the electrolyte and bring about surface stabilization. In the present invention, by employing a non-aqueous electrolyte containing a compound represented by the above chemical formula 1 as an additive, a film stabilization is realized on the surface of the positive electrode containing a high content Ni lithium composite metal oxide, thereby removing desorbed oxygen or Ni. 4+ By preventing ions from coming into contact with the electrolyte, side reactions can be reduced, and the elution of transition metals from the anode can be effectively suppressed. Meanwhile, in the present invention, the cathode active material may be, in addition to the high-content Ni-lithium composite metal oxide as described above, a lithium-manganese oxide (e.g., LiMnO2, LiMn2O4, etc.), a lithium-cobalt oxide (e.g., LiCoO2, etc.), a lithium-nickel oxide (e.g., LiNiO2, etc.), a lithium-nickel-manganese oxide (e.g., LiNi 1-Y Mn Y O2(0 <Y<1), LiMn 2-z Niz O4(0<Z<2), lithium-nickel-cobalt oxide (e.g., LiNi 1-Y1 Co Y1 O2(0 <Y1<1), 리튬-망간-코발트계 산화물(예를 들면, LiCo 1-Y2 Mn Y2 O2(0 <Y2<1), LiMn 2-z1 Co z1 O4(0<Z1<2), or Li(Ni p1 Co q1 Mn r2 )O4(0<p1<2, 0<q1<2, 0<r2<2, p1+q1+r2=2), etc. can be additionally included. The above positive electrode active material may be included in an amount of 80 to 98 wt%, more specifically 85 to 98 wt%, based on the total weight of the positive electrode active material layer. When the positive electrode active material is included in the above range, excellent capacity characteristics can be exhibited. In addition, the positive electrode active material layer of the present invention may further include a conductive material and / or a binder as needed. The conductive material is used to provide conductivity to the electrode, and in the battery to be formed, as long as it does not cause a chemical change and has electronic conductivity, it can be used without any special restrictions. Specific examples include carbon black such as carbon black, acetylene black (or Denka black), Ketjen black, channel black, furnace black, lamp black, or thermal black; graphite powder such as natural graphite, artificial graphite, or graphite with a highly developed crystal structure; conductive fibers such as carbon fibers or metal fibers; conductive powders such as fluorocarbon powder, aluminum powder, or nickel powder; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; and polyphenylene derivatives, and the like. One of these may be used alone or a mixture of two or more may be used. The above-mentioned conductive material may be included in an amount of 0.1 to 10 wt%, preferably 0.1 to 5 wt%, based on the total weight of the positive electrode active material layer. Next, the binder serves to improve the adhesion between positive electrode active material particles and the adhesion between the positive electrode active material and the current collector. Examples of such binders include a fluororesin binder including polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE); a rubber binder including styrene butadiene rubber (SBR), acrylonitrile-butadiene rubber, and styrene-isoprene rubber; a cellulose binder including carboxyl methyl cellulose (CMC), starch, hydroxy propyl cellulose, and regenerated cellulose; a polyalcohol binder including polyvinyl alcohol; a polyolefin binder including polyethylene and polypropylene; a polyimide binder; a polyester binder; and a silane binder, of which one alone or a mixture of two or more may be used. The above binder may be included in an amount of 0.1 to 15 wt%, preferably 0.1 to 10 wt%, based on the total weight of the positive electrode active material layer. The positive electrode of the present invention can be manufactured according to a positive electrode manufacturing method known in the art. For example, the positive electrode can be manufactured by a method in which a positive electrode slurry prepared by dissolving or dispersing a positive electrode active material, a binder, and / or a conductive agent in a solvent is applied onto a positive electrode current collector, followed by drying and rolling to form a positive electrode active material layer, or a method in which the positive electrode active material layer is cast onto a separate support, and then the support is peeled off to form a film, which is then laminated onto a positive electrode current collector. The positive electrode current collector is not particularly limited as long as it is conductive and does not cause a chemical change in the battery, and for example, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel surface-treated with carbon, nickel, titanium, silver, etc. may be used. In addition, the positive electrode current collector may typically have a thickness of 3 to 500 μm, and fine unevenness may be formed on the surface of the positive electrode current collector to increase the adhesive strength of the positive electrode material. For example, the positive electrode current collector may be used in various forms such as a film, sheet, foil, net, porous body, foam, or non-woven fabric. The solvent may be a solvent generally used in the relevant technical field, and may include dimethyl sulfoxide (DMSO), isopropyl alcohol, N-methylpyrrolidone (NMP), acetone, or water, and one of these may be used alone or as a mixture of two or more. The amount of the solvent used may be adjusted to an extent that the positive electrode composite has an appropriate viscosity, taking into consideration the coating thickness of the positive electrode composite, manufacturing yield, workability, etc., and is not particularly limited. (2) Cathode Next, let's explain the cathode. The negative electrode according to the present invention includes a negative electrode active material layer including a negative electrode active material, and the negative electrode active material layer may further include a conductive material and / or a binder, if necessary. As the above negative electrode active material, various negative electrode active materials used in the art can be used, for example, carbon-based negative electrode active materials, silicon-based negative electrode active materials, or mixtures thereof. According to one embodiment, the negative electrode active material may include a carbon-based negative electrode active material, and as the carbon-based negative electrode active material, various carbon-based negative electrode active materials used in the art, for example, graphite-based materials such as natural graphite, artificial graphite, and Kish graphite; high-temperature calcined carbon such as pyrolytic carbon, mesophase pitch-based carbon fiber, meso-carbon microbeads, mesophase pitches, and petroleum or coal tar pitch derived cokes, soft carbon, hard carbon, etc. may be used. The shape of the carbon-based negative electrode active material is not particularly limited, and materials of various shapes such as amorphous, plate-like, flaky, spherical, or fibrous may be used. Preferably, the carbon-based negative electrode active material may include at least one of natural graphite and artificial graphite. More preferably, the carbon-based negative electrode active material may include natural graphite and artificial graphite. When natural graphite and artificial graphite are used together, the adhesive strength with the current collector is enhanced, thereby suppressing the delamination of the active material. According to another embodiment, the negative electrode active material may include a silicon-based negative electrode active material together with the carbon-based negative electrode active material. The above silicon-based negative electrode active material is, for example, metallic silicon (Si), silicon oxide (SiO x, here 0 <x<2) 실리콘 탄화물(SiC) 및 Si-Y 합금(상기 Y는 알칼리 금속, 알칼리 토금속, 13족 원소, 14족 원소, 전이금속, 희토류 원소 및 이들의 조합으로 이루어진 군에서 선택되는 원소이며, Si은 아님)로 이루어진 군으로부터 선택된 1종 이상을 포함할 수 있다. 상기 원소 Y로는 Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db (dubnium), Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ti, Ge, P, As, Sb, Bi, S, Se, Te, Po, 및 이들의 조합으로 이루어진 군에서 선택될 수 있다. Since the silicon-based negative electrode active material exhibits higher capacity characteristics than the carbon-based negative electrode active material, when the silicon-based negative electrode active material is additionally included, even better capacity characteristics can be obtained. However, in the case of the negative electrode containing the silicon-based negative electrode active material, compared to the graphite negative electrode, the SEI film contains more oxygen (O)-rich components, and the SEI film containing O-rich components tends to be more easily decomposed when a Lewis acid such as HF or PF5 is present in the electrolyte. Therefore, in the case of the negative electrode containing the silicon-based negative electrode active material, in order to maintain a stable SEI film, it is necessary to suppress the generation of Lewis acids such as HF and PF5 in the electrolyte, or to remove (or scavenge) the generated Lewis acid. Since the non-aqueous electrolyte according to the present invention includes an electrolyte additive capable of forming a stable film on the positive and negative electrodes, it can effectively suppress the decomposition of the SEI film when using the negative electrode containing the silicon-based active material. Meanwhile, the carbon-based negative electrode active material and the silicon-based negative electrode active material may be in a ratio of 1:99 to 97:3, preferably 85:15 to 95:5, and more preferably 90:10 to 97:3. When the mixing ratio of the silicon-based negative electrode active material and the carbon-based negative electrode active material satisfies the above range, the capacity characteristics are improved while the volume expansion of the silicon-based negative electrode active material is suppressed, thereby ensuring excellent cycle performance. The above negative electrode active material may be included in an amount of 80 wt% to 99 wt% based on the total weight of the negative electrode active material layer. When the content of the negative electrode active material satisfies the above range, excellent capacity characteristics and electrochemical characteristics can be obtained. Next, the conductive agent is a component for further improving the conductivity of the negative electrode active material, and may be added in an amount of 10 wt% or less, preferably 5 wt% or less, based on the total weight of the negative electrode active material layer. The conductive agent is not particularly limited as long as it has conductivity without causing a chemical change in the battery, and examples thereof include carbon black such as carbon black, acetylene black (or Denka black), Ketjen black, channel black, furnace black, lamp black, or thermal black; graphite powder such as natural graphite, artificial graphite, or graphite with a highly developed crystal structure; conductive fibers such as carbon fibers or metal fibers; conductive powders such as fluorocarbon powder, aluminum powder, or nickel powder; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; and polyphenylene derivatives. The binder is a component that assists in bonding between the conductive material, the active material, and the current collector, and is typically added in an amount of 0.1 wt% to 10 wt% based on the total weight of the negative electrode active material layer. Examples of the binder include a fluororesin binder including polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE); a rubber binder including styrene butadiene rubber (SBR), acrylonitrile-butadiene rubber, and styrene-isoprene rubber; a cellulose binder including carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, and regenerated cellulose; a polyalcohol binder including polyvinyl alcohol; a polyolefin binder including polyethylene and polypropylene; and a polyimide binder. Polyester binders; and silane binders, etc. The above binder may be included in an amount of 0.1 to 15 wt%, preferably 0.1 to 10 wt%, based on the total weight of the negative electrode active material layer. The above negative electrode can be manufactured according to a negative electrode manufacturing method known in the art. For example, the negative electrode can be manufactured by applying a negative electrode slurry prepared by dissolving or dispersing a negative electrode active material and optionally a binder and a conductive material in a solvent on a negative electrode current collector, rolling, and drying to form an active material layer, or by casting the negative electrode active material layer on a separate support, then peeling off the support, and laminating the resulting film on a negative electrode current collector. The negative electrode current collector is not particularly limited as long as it has high conductivity without causing chemical changes in the battery. For example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel surface-treated with carbon, nickel, titanium, silver, etc., aluminum-cadmium alloy, etc. can be used. In addition, the negative electrode current collector can typically have a thickness of 3 ㎛ to 500 ㎛, and like the positive electrode current collector, fine unevenness can be formed on the surface of the current collector to strengthen the bonding strength of the negative electrode active material. For example, it can be used in various forms such as a film, a sheet, a foil, a net, a porous body, a foam, a non-woven fabric, etc. The solvent may be a solvent generally used in the relevant technical field, and may include dimethyl sulfoxide (DMSO), isopropyl alcohol, N-methylpyrrolidone (NMP), acetone, or water, and one of these may be used alone or a mixture of two or more thereof. The amount of the solvent used may be adjusted to an extent that the negative electrode slurry has an appropriate viscosity, taking into consideration the coating thickness of the negative electrode composite, manufacturing yield, workability, etc., and is not particularly limited. (3) Membrane A lithium secondary battery according to the present invention includes a separator between the positive electrode and the negative electrode. The above separator separates the negative electrode and the positive electrode and provides a passage for lithium ions to move. If it is a separator commonly used in lithium secondary batteries, it can be used without any special restrictions. In particular, it is preferable that it have low resistance to ion movement of lithium salt and excellent electrolyte absorption capacity. Specifically, a porous polymer film, for example, a porous polymer film made of a polyolefin polymer such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, and an ethylene / methacrylate copolymer, or a laminated structure of two or more layers thereof, may be used as the separator. In addition, a conventional porous nonwoven fabric, for example, a nonwoven fabric made of high-melting-point glass fiber, polyethylene terephthalate fiber, etc. may be used. In addition, a coated separator containing a ceramic component or a polymer material to secure heat resistance or mechanical strength may be used, and may optionally be used in a single-layer or multi-layer structure. The lithium secondary battery according to the present invention as described above can be usefully used in portable devices such as mobile phones, laptop computers, and digital cameras, and electric vehicles such as hybrid electric vehicles (HEVs). Accordingly, according to another embodiment of the present invention, a battery module including the lithium secondary battery as a unit cell and a battery pack including the same are provided. The above battery module or battery pack can be used as a power source for one or more medium- to large-sized devices, such as power tools; electric vehicles including electric vehicles (EVs), hybrid electric vehicles, and plug-in hybrid electric vehicles (PHEVs); or power storage systems. There is no particular limitation on the external shape of the lithium secondary battery of the present invention, but it may be a cylindrical shape using a can, a square shape, a pouch shape, or a coin shape. The lithium secondary battery according to the present invention can be used not only as a battery cell used as a power source for a small device, but can also be preferably used as a unit battery in a medium- to large-sized battery module including a plurality of battery cells. Hereinafter, the present invention will be described in detail through specific examples. Example I. Manufacturing of electrolyte additives for secondary batteries Example 1. Ethyl formate (manufacturer: Merck), propylene oxide (manufacturer: Merck), and dimethyl hydrazine (manufacturer: Merck) were dissolved in isopropyl alcohol (manufacturer: Merck), and then stirred at 55°C for 72 hours (see Reaction Scheme 2 below). Subsequently, the solvent was removed using a solvent condenser (manufacturer: heidloph), and then recrystallized using ethyl acetate to obtain a white solid. The obtained white solid was dried in a vacuum oven to obtain a compound of chemical formula 1A (see Figure 1) (yield: 71%). [Reaction Formula 2] Example 2. Methyl formate (manufacturer: Merck), propylene oxide, and dimethyl hydrazine were dissolved in isopropyl alcohol, and then stirred at 55°C for 72 hours (see Reaction Scheme 3 below). Subsequently, the solvent was removed using a solvent condenser, and then recrystallized using ethyl acetate to obtain a white solid. The obtained white solid was dried in a vacuum oven to obtain a compound of chemical formula 1B (see Figure 2) (yield: 83%). [Reaction Formula 3] II. Lithium secondary battery manufacturing Example 3. (Manufacture of non-aqueous electrolyte for lithium secondary batteries) LiPF6 was dissolved to 1.2 M in a non-aqueous organic solvent containing ethylene carbonate (EC) and dimethyl carbonate (DMC) in a volume ratio of 30:70, and then 0.5 wt% of a compound represented by the chemical formula 1A and 2.0 wt% of vinylene carbonate and 1.0 wt% of 1,3-propane sultone as other additives were added to prepare a non-aqueous electrolyte for a lithium secondary battery. (Polar electrode manufacturing) Positive electrode active material particles (Li(Ni) 0.8 Co 0.1 Mn 0.1 )O2), carbon black as a conductive agent, and polyvinylidene fluoride (PVDF) as a binder were added to N-methyl-2-pyrrolidone (NMP) as a solvent in a weight ratio of 97.5:1:1.5 to prepare a positive electrode active material slurry (solid content 48 wt%). The positive electrode active material slurry was applied to a positive electrode current collector (Al thin film) having a thickness of 15 μm, dried, and then roll pressed to prepare a positive electrode. (Cathode manufacturing) A negative electrode active material slurry (solid content: 70 wt%) was prepared by adding a negative electrode active material (natural graphite:SiO = 96:4 weight ratio), PVDF as a binder, and carbon black as a conductive material in a weight ratio of 95:3.5:1.5 to a solvent, NMP. The negative electrode active material slurry was applied to a negative electrode current collector (Cu thin film) having a thickness of 6 μm, dried, and then roll pressed to prepare a negative electrode. (Secondary battery manufacturing) An electrode assembly was manufactured by a conventional method of sequentially laminating the positive and negative electrodes manufactured by the above-described method together with a polyethylene porous film, and then this was placed in a cylindrical secondary battery case, and the non-aqueous electrolyte for a lithium secondary battery manufactured as described above was injected to manufacture a lithium secondary battery. Example 4. (Manufacture of non-aqueous electrolyte for lithium secondary batteries) A non-aqueous electrolyte for a lithium secondary battery was prepared in the same manner as in Example 3, except that 1.0 wt% of a compound represented by Chemical Formula 1A and 2.0 wt% of vinylene carbonate and 1.0 wt% of 1,3-propane sultone were added to a non-aqueous organic solvent. (Secondary battery manufacturing) A lithium secondary battery was manufactured in the same manner as Example 3, except that the non-aqueous electrolyte for the lithium secondary battery manufactured above was injected. Example 5. (Manufacture of non-aqueous electrolyte for lithium secondary batteries) A non-aqueous electrolyte for a lithium secondary battery was prepared in the same manner as in Example 3, except that 3.0 wt% of a compound represented by Chemical Formula 1A and 2.0 wt% of vinylene carbonate and 1.0 wt% of 1,3-propane sultone were added to a non-aqueous organic solvent. (Secondary battery manufacturing) A lithium secondary battery was manufactured in the same manner as Example 3, except that the non-aqueous electrolyte for the lithium secondary battery manufactured above was injected. Example 6. (Manufacture of non-aqueous electrolyte for lithium secondary batteries) A non-aqueous electrolyte for a lithium secondary battery was prepared in the same manner as in Example 3, except that the compound represented by Chemical Formula 1B was added instead of the compound represented by Chemical Formula 1A to the non-aqueous organic solvent. (Secondary battery manufacturing) A lithium secondary battery was manufactured in the same manner as Example 3, except that the non-aqueous electrolyte for the lithium secondary battery manufactured above was injected. Example 7. (Manufacture of non-aqueous electrolyte for lithium secondary batteries) A non-aqueous electrolyte for a lithium secondary battery was prepared in the same manner as in Example 4, except that the compound represented by Chemical Formula 1B was added instead of the compound represented by Chemical Formula 1A to the non-aqueous organic solvent. (Secondary battery manufacturing) A lithium secondary battery was manufactured in the same manner as Example 4, except that the non-aqueous electrolyte for the lithium secondary battery manufactured above was injected. Example 8. (Manufacture of non-aqueous electrolyte for lithium secondary batteries) A non-aqueous electrolyte for a lithium secondary battery was prepared in the same manner as in Example 5, except that the compound represented by Chemical Formula 1B was added to the non-aqueous organic solvent instead of the compound represented by Chemical Formula 1A. (Secondary battery manufacturing) A lithium secondary battery was manufactured in the same manner as Example 5, except that the non-aqueous electrolyte for the lithium secondary battery manufactured above was injected. Example 9. (Manufacture of non-aqueous electrolyte for lithium secondary batteries) A non-aqueous electrolyte for a lithium secondary battery was prepared in the same manner as in Example 4, except that the compound represented by Chemical Formula 1C was added instead of the compound represented by Chemical Formula 1A to the non-aqueous organic solvent. (Secondary battery manufacturing) A lithium secondary battery was manufactured in the same manner as Example 4, except that the non-aqueous electrolyte for the lithium secondary battery manufactured above was injected. Example 10. (Manufacture of non-aqueous electrolyte for lithium secondary batteries) A non-aqueous electrolyte for a lithium secondary battery was prepared in the same manner as in Example 4, except that the compound represented by Chemical Formula 1D was added instead of the compound represented by Chemical Formula 1A to the non-aqueous organic solvent. (Secondary battery manufacturing) A lithium secondary battery was manufactured in the same manner as Example 4, except that the non-aqueous electrolyte for the lithium secondary battery manufactured above was injected. Example 11. (Manufacture of non-aqueous electrolyte for lithium secondary batteries) A non-aqueous electrolyte for a lithium secondary battery was prepared in the same manner as in Example 3, except that 10.0 wt% of a compound represented by Chemical Formula 1A and 2.0 wt% of vinylene carbonate and 1.0 wt% of 1,3-propane sultone were added to a non-aqueous organic solvent as other additives. (Secondary battery manufacturing) A lithium secondary battery was manufactured in the same manner as Example 3, except that the non-aqueous electrolyte for the lithium secondary battery manufactured above was injected. Example 12. (Manufacture of non-aqueous electrolyte for lithium secondary batteries) A non-aqueous electrolyte for a lithium secondary battery was prepared in the same manner as in Example 3, except that 0.1 wt% of a compound represented by Chemical Formula 1A and 2.0 wt% of vinylene carbonate and 1.0 wt% of 1,3-propane sultone were added to a non-aqueous organic solvent as other additives. (Secondary battery manufacturing) A lithium secondary battery was manufactured in the same manner as Example 3, except that the non-aqueous electrolyte for the lithium secondary battery manufactured above was injected. Comparative Example 1. (Manufacture of non-aqueous electrolyte for lithium secondary batteries) LiPF6 was dissolved to 1.2 M in a non-aqueous organic solvent containing ethylene carbonate (EC) and dimethyl carbonate (DMC) in a volume ratio of 30:70, and then 2.0 wt% of vinylene carbonate and 1.0 wt% of 1,3-propane sultone were added to prepare a non-aqueous electrolyte for a lithium secondary battery. (Secondary battery manufacturing) A lithium secondary battery was manufactured in the same manner as in Example 3, except that the non-aqueous electrolyte for a lithium secondary battery manufactured above was injected instead of the non-aqueous electrolyte for a lithium secondary battery of Example 3. Comparative Example 2. (Manufacture of non-aqueous electrolyte for lithium secondary batteries) A non-aqueous electrolyte for a lithium secondary battery was prepared in the same manner as in Example 3, except that a compound represented by the following chemical formula 3 was added instead of the compound represented by the chemical formula 1A. [Chemical Formula 3] (Secondary battery manufacturing) A lithium secondary battery was manufactured in the same manner as Example 3, except that the non-aqueous electrolyte for the lithium secondary battery manufactured above was injected. Comparative Example 3. (Manufacture of non-aqueous electrolyte for lithium secondary batteries) A non-aqueous electrolyte for a lithium secondary battery was prepared in the same manner as in Example 3, except that a compound represented by the following chemical formula 4 was added instead of the compound represented by the chemical formula 1A. [Chemical Formula 4] (Secondary battery manufacturing) A lithium secondary battery was manufactured in the same manner as Example 3, except that the non-aqueous electrolyte for the lithium secondary battery manufactured above was injected. Lithium salt, non-aqueous organic solvent, additive, other additives (wt%), chemical formula, content (wt%), Example 31.2M LiPF6, EC:DMC = 30:70, volume ratio 1A0.5, VC 2.0 / PS 1.0, Example 41A1.0, Example 51A3.0, Example 61B0.5, Example 71B1.0, Example 81B3.0, Example 91C1.0, Example 101D1.0, Example 111A10.0, Example 121A0.1, Comparative Example 1--Comparative Example 230.5, Comparative Example 340.5 Meanwhile, the abbreviations of the compounds in Table 1 above mean the following. EC: Ethylene carbonate EMC: Ethyl methyl carbonate VC: Vinylene Carbonate PS: 1,3-propanesultone Experimental example Experimental Example 1: Evaluation of Capacity Retention Rate after High-Temperature Storage The lithium secondary batteries manufactured in Examples 3 to 12 and the lithium secondary batteries manufactured in Comparative Examples 1 to 3 were fully charged (SOC 100%) to 4.25 V, 0.05 C cut off, under constant current / constant voltage conditions at 0.5 C rate at room temperature (25°C), discharged to 2.5 V under constant current conditions at 0.5 C rate, and then the discharge capacity before high-temperature storage was measured using a PNE-0506 charger / discharger (manufacturer: PNE solution). Then, after storing at 55°C for two months, the post-high-temperature storage capacity of each lithium secondary battery was measured, and the high-temperature capacity retention rate (%) was calculated using the following [Equation 1]. The results are shown in Table 2 below. [Formula 1] Capacity retention rate (%) = (Discharge capacity after 2 months of high-temperature storage / Discharge capacity before high-temperature storage) × 100 Experimental Example 2. Evaluation of resistance increase rate after high-temperature storage The lithium secondary batteries manufactured in Examples 3 to 12 and the lithium secondary batteries manufactured in Comparative Examples 1 to 3 were each charged to 4.25 V at a 0.5 C rate under constant current / constant voltage conditions at room temperature (25°C), then discharged to a DOD (depth of discharge) of 50% to achieve a SOC of 50%, and then discharged for 10 seconds under a 0.5 C rate condition, and the initial resistance was measured using a PNE-0506 charger / discharger (manufacturer: PNE solution). Then, after storing at 55℃ for two months, the resistance value of each lithium secondary battery was measured, and the resistance increase rate (%) was calculated using the following [Equation 2]. The results are shown in Table 2 below. [Formula 2] Resistance increase rate (%) = {(Resistance value after 2 months of high-temperature storage - Resistance value before high-temperature storage) / Resistance value before high-temperature storage} × 100 Experimental Example 3. Evaluation of Gas Emission After High-Temperature Storage The lithium secondary batteries manufactured in Examples 3 to 12 and the lithium secondary batteries manufactured in Comparative Examples 1 to 3 were each fully charged to 4.25 V SOC 100% at room temperature (25°C) at a 0.5 C rate under constant current / constant voltage conditions. Then, after storing at 72℃ for 2 months, the amount of gas evolution (%) after high-temperature storage for each lithium secondary battery was measured, and the results are shown in Table 2 below. Capacity retention rate after high temperature storage (%) Resistance increase rate after high temperature storage (%) Gas generation amount after high temperature storage (%) Example 395.77.411.4 Example 495.66.912.5 Example 595.18.114.1 Example 695.57.013.2 Example 795.57.412.6 Example 895.08.115.7 Example 994.88.113.9 Example 1093.98.514.7 Example 1193.110.120.4 Example 1294.87.212.2 Comparative example 192.115.830.3 Comparative example 293.318.335.1 Comparative example 392.721.137.2 Looking at Table 2 above, it can be seen that the secondary batteries of Examples 3 to 12 of the present invention have improved capacity retention rate (%) after high-temperature storage, resistance increase rate (%) after high-temperature storage, and gas generation amount (%) compared to the secondary batteries of Comparative Examples 1 to 3.

Claims

1. An electrolyte additive for a secondary battery comprising a compound represented by the following chemical formula 1: [Chemical Formula 1] In the above chemical formula 1, Ra is an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, -(R)n-R0 (R is oxygen or an alkylene group having 1 to 3 carbon atoms, R0 is an aryl group having 6 to 10 carbon atoms, and n is at least one integer from 0 to 5), or -R1-O-R2 (R1 is an alkylene group having 1 to 3 carbon atoms, and R2 is an aryl group having 6 to 10 carbon atoms), Rb, Rc and Rd are each independently hydrogen or an alkyl group having 1 to 10 carbon atoms.

2. In claim 1, An electrolyte additive for a secondary battery, wherein the alkyl group or alkoxy group is substituted with an alkyl group having 1 to 3 carbon atoms or at least one fluorine.

3. In claim 1, In the above chemical formula 1, Ra is an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, -(R)n-R0 (R is oxygen or an alkylene group having 1 to 3 carbon atoms, R0 is an aryl group having 6 to 8 carbon atoms, and n is at least one integer from 0 to 3), or -R1-O-R2 (R1 is an alkylene group having 1 to 3 carbon atoms, and R2 is an aryl group having 6 to 8 carbon atoms), An electrolyte additive for a secondary battery, wherein Rb, Rc and Rd are each independently hydrogen or an alkyl group having 1 to 8 carbon atoms.

4. In claim 1, In the above chemical formula 1, Ra is an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, -(R)n-R0 (R is oxygen or an alkylene group having 1 to 3 carbon atoms, R0 is an aryl group having 6 to 8 carbon atoms, and n is an integer of 0 or 1), An electrolyte additive for a secondary battery, wherein Rb, Rc and Rd are each independently hydrogen or an alkyl group having 1 to 5 carbon atoms.

5. In claim 1, In the above chemical formula 1, Ra is an alkyl group having 1 to 3 carbon atoms or -(R)n-R0 (R is oxygen or an alkylene group having 1 to 3 carbon atoms, R0 is an aryl group having 6 to 8 carbon atoms, and n is an integer of 0 or 1), An electrolyte additive for a secondary battery, wherein Rb, Rc and Rd are each independently an alkyl group having 1 to 3 carbon atoms.

6. In claim 1, An electrolyte additive for a secondary battery, wherein the compound represented by the above chemical formula 1 is at least one selected from the group consisting of compounds represented by the following chemical formulas 1A to 1D: [Chemical Formula 1A] [Chemical Formula 1B] [Chemical Formula 1C] [Chemical Formula 1D] .

7. A non-aqueous electrolyte for a lithium secondary battery comprising the electrolyte additive for a secondary battery of claim 1.

8. In claim 7, A non-aqueous electrolyte for a lithium secondary battery, wherein the electrolyte additive for the secondary battery is included in an amount of 0.1 wt% to 10.0 wt% based on the total weight of the non-aqueous electrolyte for a lithium secondary battery.

9. In claim 7, A non-aqueous electrolyte for a lithium secondary battery, wherein the non-aqueous electrolyte further comprises a lithium salt and a non-aqueous organic solvent.

10. In claim 7, The non-aqueous electrolyte for a lithium secondary battery further comprises at least one other additive selected from the group consisting of a carbonate compound, a sultone compound, a sulfate compound, a phosphate or phosphite compound, a borate compound, a nitrile compound, an amine compound, a silane compound, and a lithium salt compound, which are substituted or unsubstituted with a halogen.

11. A cathode containing a cathode active material; A negative electrode comprising a negative active material; A separator interposed between the cathode and the anode; and A lithium secondary battery comprising a non-aqueous electrolyte for a lithium secondary battery according to claim 7.

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