Nonaqueous electrolyte and lithium secondary battery comprising same

Abstract

The present invention provides a nonaqueous electrolyte comprising a lithium salt, an organic solvent, and a compound represented by chemical formula 1. In chemical formula 1, R1 and R2 are each independently any one selected from the group consisting of H, -OC≡CH, F, a nitrile group, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, and an alkynyl group having 2 to 10 carbon atoms.

Description

Non-aqueous electrolyte and lithium secondary battery containing the same [Cross-reference with related applications] This application claims the benefit of priority from Korean Patent Application No. 10-2023-0189042, filed December 21, 2023, the entire contents of which are incorporated herein by reference. [Technical Field] The present invention relates to a non-aqueous electrolyte and a lithium secondary battery including the same. Recently, as the application areas of lithium secondary batteries have rapidly expanded to include not only power supply for electronic devices such as electric, electronic, communication, and computers, but also power storage and supply for large-area devices such as automobiles and power storage devices, the demand for high-capacity, high-output, and high-stability secondary batteries is increasing. In particular, high capacity, high output, and long life characteristics are becoming important in lithium secondary batteries for automotive use. In order to increase the capacity of secondary batteries, nickel-rich cathode active materials with high energy density but low stability can be used, or secondary batteries can be driven at high voltage. However, when the secondary battery is operated under the above conditions, as charge and discharge progress, the film formed on the surface of the positive / negative electrode or the electrode surface structure may deteriorate due to a side reaction caused by deterioration of the electrolyte, and thus transition metal ions may be eluted from the surface of the positive electrode. In this way, the eluted transition metal ions are electro-deposited on the negative electrode and reduce the passivation ability of the SEI, which causes a problem of deterioration of the negative electrode. This deterioration phenomenon of secondary batteries tends to accelerate when the potential of the positive electrode increases or when the battery is exposed to high temperatures. In addition, when lithium-ion batteries are used continuously for a long time or are left at high temperatures, gas is generated, causing the thickness of the battery to increase, which is known as swelling. It is known that the amount of gas generated at this time is determined by the state of the SEI. Therefore, in order to solve these problems, research and development are being attempted on methods to suppress the dissolution of metal ions at the positive electrode, form a stable SEI film at the negative electrode, reduce the swelling phenomenon of the secondary battery, and increase stability at high temperatures. As a result of conducting multifaceted research to solve the above problems, the present invention aims to provide an additive for a non-aqueous electrolyte that can suppress the deterioration of the positive electrode, reduce side reactions between the positive electrode and the electrolyte, and form a stable SEI film on the negative electrode. In addition, the present invention aims to provide a non-aqueous electrolyte having improved stability at high temperatures by including the non-aqueous electrolyte additive. In addition, the present invention aims to provide a lithium secondary battery having improved high-temperature cycle characteristics and high-temperature storage characteristics by including the non-aqueous electrolyte, thereby improving overall performance. [1] The present invention provides a non-aqueous electrolyte comprising a lithium salt; an organic solvent; and a compound represented by the following chemical formula 1: [Chemical Formula 1] In the above chemical formula 1, R1 and R2 are each independently any one selected from the group consisting of H, -OC≡CH, F, a nitrile group, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, and an alkynyl group having 2 to 10 carbon atoms. [2] The present invention can provide a non-aqueous electrolyte in which, in the above [1], the compound of the chemical formula 1 is one selected from the group consisting of additives for non-aqueous electrolytes represented by the following chemical formulas 1-2a to 1-2e. [Chemical Formula 1-2a] [Chemical Formula 1-2b] [Chemical formula 1-2c] [Chemical formula 1-2d] [Chemical Formula 1-2e] [3] The present invention can provide a non-aqueous electrolyte in which the compound of the chemical formula 1 is included in an amount of 0.01 to 10 parts by weight per 100 parts by weight of the non-aqueous electrolyte in [1] or [2]. [4] The present invention can provide a non-aqueous electrolyte in which the lithium salt is included in a concentration of 0.5 M to 2.0 M in any one of the above [1] to [3]. [5] The present invention is one of the above [1] to [4], wherein 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, LiN(SO2CF2CF3)2, and LiN(SO2CF3)2. [6] The present invention can provide a non-aqueous electrolyte comprising at least one organic solvent selected from the group consisting of a cyclic carbonate-based organic solvent, a linear carbonate-based organic solvent, a linear ester-based organic solvent, and a cyclic ester-based organic solvent, in any one of the above [1] to [5]. [7] The present invention can provide a non-aqueous electrolyte further comprising, as an additive, at least one compound selected from the group consisting of cyclic carbonate compounds, halogen-substituted carbonate compounds, sultone compounds, sulfate compounds, phosphate compounds, borate compounds, nitrile compounds, benzene compounds, amine compounds, silane compounds, and lithium salt compounds in any one of the above [1] to [6]. [8] The present invention can provide a lithium secondary battery including a positive electrode; a negative electrode; and a non-aqueous electrolyte of any one of [1] to [7]. [9] The present invention can provide a lithium secondary battery in which, in the above [8], the positive electrode is a lithium nickel-based oxide represented by the following [chemical formula 2] as a positive electrode active material. [Chemical formula 2] Li x Ni a Co b M 1 c M 2 d O2 In the above chemical formula 2, M 1 is Mn, Al or a combination of these, and M 2 is at least one selected from the group consisting of Zr, W, Y, Ba, Ca, Ti, Mg, Ta and Nb, and 0.8≤x≤1.2, 0.6≤a<1, 0 <b<0.4, 0<c<0.4, 0≤d≤0.1이다.

[0010] The present invention, in the above [8] or [9], the negative electrode is SiO as a negative electrode active material. x A lithium secondary battery including (0≤x<2) can be provided. The compound represented by the chemical formula 1 provided as an additive for a non-aqueous electrolyte of the present invention is characterized in that a propargyl group and a sultone ring are connected by an ether group. In the additive of the chemical formula 1, the ether group bond is easily broken during initial charging, and the compound having a sultone ring structure together with the propargyl group forms a polymeric organic film on the negative electrode. In addition, the sultone ring compound remaining after the formation of the polymeric cathode SEI film can be partially decomposed on the cathode surface as the cathode reaches a high potential to form an anode protective film. That is, by using the non-aqueous electrolyte of the present invention including the compound of the above chemical formula 1, an electrode-electrolyte interface that is stable even at high temperatures and has low resistance can be formed, so that high-temperature cycle characteristics and high-temperature storage characteristics are improved, and a lithium secondary battery with improved overall performance can be implemented. The terms or words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as having 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 manner. It should be understood that the terms “comprise,” “include,” or “have,” as used herein, are intended to specify the presence of a feature, number, step, component, or combination thereof, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, components, or combinations thereof. In addition, in the description of "carbon atoms a to b" in the present specification, "a" and "b" mean the number of carbon atoms included in a specific functional group. That is, the functional group may include "a" to "b" carbon atoms. For example, "an alkylene group having 1 to 5 carbon atoms" means an alkylene group including 1 to 5 carbon atoms, i.e., -CH2-, -CH2CH2-, -CH2CH2CH2-, -CH2(CH3)CH-, -CH(CH3)CH2-, and -CH(CH3)CH2CH2-. In addition, in the present specification, the alkyl group, alkenyl group, and alkynyl group may all be substituted or unsubstituted. The term "substitution", unless otherwise defined, means that at least one hydrogen bonded to carbon is substituted with an element other than hydrogen, for example, it means substituted with a halogen atom such as F, Cl, etc. Hereinafter, the present invention will be described in more detail. The non-aqueous electrolyte and / or lithium secondary battery according to the present invention comprises at least one of the configurations disclosed below, and may comprise any combination between technically possible configurations among the configurations below. Electrolyte of the dagger The non-aqueous electrolyte of the present invention is characterized by containing a compound of the following chemical formula 1 as an additive. [Chemical Formula 1] In the above chemical formula 1, R1 and R2 are each independently any one selected from the group consisting of H, -OC≡CH, F, a nitrile group, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, and an alkynyl group having 2 to 10 carbon atoms. Preferably, R1 and R2 can each independently be any one selected from the group consisting of H, -OC≡CH, F, a nitrile group, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, and an alkynyl group having 2 to 5 carbon atoms, and most preferably H, -OC≡CH, F, a nitrile group. The compound represented by the chemical formula 1 provided as an additive for a non-aqueous electrolyte of the present invention is characterized in that a propargyl group and a sultone ring are connected by an ether group. The additive of the chemical formula 1 easily breaks the ether group bond during initial charging, and the compound having a sultone ring structure together with the propargyl group forms a polymeric organic film on the negative electrode. In particular, since the propane sultone group has an appropriate level of reactivity, it does not excessively increase the initial resistance and is not rapidly consumed at the initial stage, so that the long-life performance of a lithium secondary battery including it can be improved. In addition, the sultone ring compound remaining after the formation of the polymeric cathode SEI film can be partially decomposed on the cathode surface as the cathode reaches a high potential to form an anode protective film. That is, when the non-aqueous electrolyte of the present invention including the compound of the above chemical formula 1 is used, a cathode film and anode film with excellent durability are formed, so that high-temperature cycle characteristics and high-temperature storage characteristics are improved, thereby realizing a lithium secondary battery with improved overall performance. Furthermore, in the case of the compounds of chemical formula 1 of the present invention, there is an OC≡CH substituent at the 1st carbon position of propane sultone, which is the site where propane sultone binds to DNA of the human body, so there is an effect of reducing biotoxicity. The additive for a non-aqueous electrolyte according to the present invention may be any one selected from the group consisting of the following chemical formulas 1-2a to 1-2e. [Chemical Formula 1-2a] [Chemical Formula 1-2b] [Chemical formula 1-2c] [Chemical formula 1-2d] [Chemical Formula 1-2e] The additive for a non-aqueous electrolyte according to the present invention may be included in an amount of 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, and more preferably 0.5 to 1 part by weight, based on 100 parts by weight of the non-aqueous electrolyte. When the amount of the compound represented by the chemical formula 1 satisfies the above range, the effect of forming a film on the positive electrode is sufficient, so that the elution of transition metal from the positive electrode active material is suppressed, and the viscosity of the electrolyte is maintained at an appropriate level, so that the rate characteristics and life characteristics are excellent when stored at high temperatures. The non-aqueous electrolyte according to the present invention may include a lithium salt and an organic solvent. The above lithium salt is used as an electrolyte salt in a lithium secondary battery and is used as a medium for transferring ions. Typically, the lithium salt is used as a cation, for example, Li + , 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 may be mentioned. Specifically, the lithium salts are 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(perfluoroethanesulfonyl)imide; LiBETI), and LiN(SO2CF3)2 (lithium bis(trifluoromethanesulfonyl)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 may be appropriately changed within a normally usable range, but in order to obtain an optimal effect of forming a film for preventing corrosion of the electrode surface, it may be included in the electrolyte at a concentration of 0.5 M to 2.0 M, preferably, a concentration of 0.5 M to 1.8 M, and more preferably, a concentration of 0.7 M to 1.6 M. When the concentration of the lithium salt satisfies the above range, the effect of improving the cycle characteristics during high-temperature storage of a lithium secondary battery is sufficient, and the viscosity of the non-aqueous electrolyte is appropriate, so that the electrolyte impregnation property can be improved. The above non-aqueous organic solvent may include at least one organic solvent selected from the group consisting of a cyclic carbonate-based organic solvent, a linear carbonate-based organic solvent, a linear ester-based organic solvent, and a cyclic ester-based organic solvent. Specifically, the 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 having a high dielectric constant and thus capable of dissociating a lithium salt in an electrolyte well. Specific examples thereof include at least one 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, ethylene carbonate may be included. In addition, the linear carbonate-based organic solvent is an organic solvent having low viscosity and low dielectric constant, and representative examples thereof include at least one organic solvent selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, ethyl methyl carbonate (EMC), methyl propyl carbonate, and ethyl propyl carbonate, and specifically, ethyl methyl carbonate (EMC) may be included. In addition, the organic solvent may additionally include at least one ester organic solvent selected from the group consisting of linear ester organic solvents and cyclic ester organic solvents in addition to at least one carbonate organic solvent selected from the group consisting of cyclic carbonate organic solvents and linear carbonate organic solvents, in order to produce an electrolyte having high ionic conductivity. Specific examples of such linear ester organic solvents include at least one 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 organic solvent may include at least one organic solvent selected from the group consisting of γ-butyrolactone, γ-valerolactone, γ-caprolactone, σ-valerolactone, and ε-caprolactone. Meanwhile, the organic solvent may be used without limitation by adding an organic solvent commonly used in a non-aqueous electrolyte as needed. For example, at least one organic solvent from among an ether-based organic solvent, a glyme-based solvent, and a nitrile-based organic solvent may be additionally included. As the above ether solvent, any one selected from the group consisting 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) or a mixture of two or more thereof may be used, but is not limited thereto. The above-mentioned glyme-based solvent has a high dielectric constant and low surface tension compared to linear carbonate-based organic solvents, and is a solvent with low reactivity with metals, and may include at least one selected from the group consisting of dimethoxyethane (glyme, DME), diethoxyethane, diglyme, tri-glyme, and tetra-glyme (TEGDME), but is not limited thereto. The above nitrile solvent may be at least one selected from the group consisting of acetonitrile, propionitrile, butyronitrile, valeronitrile, caprylonitrile, heptanenitrile, cyclopentane carbonitrile, cyclohexane carbonitrile, 2-fluorobenzonitrile, 4-fluorobenzonitrile, difluorobenzonitrile, trifluorobenzonitrile, phenylacetonitrile, 2-fluorophenylacetonitrile, and 4-fluorophenylacetonitrile, but is not limited thereto. In addition, the non-aqueous electrolyte of the present invention may additionally include a known electrolyte additive in the non-aqueous electrolyte, if necessary, in order to prevent the non-aqueous electrolyte from being decomposed and causing cathode collapse in a high-power environment, or to further improve low-temperature high-rate discharge characteristics, high-temperature stability, overcharge prevention, and high-temperature battery expansion suppression effects. These other electrolyte additives may include at least one SEI film forming additive selected from the group consisting of, for example, cyclic carbonate compounds, halogen-substituted carbonate compounds, sultone compounds, sulfate compounds, phosphate compounds, borate compounds, nitrile compounds, benzene compounds, amine compounds, silane compounds, and lithium salt compounds. The above cyclic carbonate compound may include vinylene carbonate (VC) or vinylethylene carbonate. The above halogen-substituted carbonate compound may include fluoroethylene carbonate (FEC). The above sultone compounds may include at least one compound selected from the group consisting of 1,3-propane sultone (PS), 1,4-butane sultone, ethene sultone, 1,3-propene sultone (PRS), 1,4-butene sultone, and 1-methyl-1,3-propene sultone. The above sulfate compounds may include ethylene sulfate (Esa), trimethylene sulfate (TMS), or methyl trimethylene sulfate (MTMS). The above phosphate compound may include at least one compound selected from the group consisting of lithium difluoro(bisoxalato)phosphate, lithium difluorophosphate, tris(trimethylsilyl)phosphate, tris(trimethylsilyl)phosphite, tris(2,2,2-trifluoroethyl)phosphate, and tris(2,2,2-trifluoroethyl)phosphite. The above borate compounds include tetraphenylborate, lithium oxalyldifluoroborate (LiODFB), and lithium bisoxalatoborate (LiB(C2O4)2, LiBOB). The above nitrile compound may include 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 benzene compound may include fluorobenzene, the amine compound may include triethanolamine or ethylene diamine, and the silane compound may include tetravinylsilane. The above lithium salt compound is a compound different from the lithium salt included in the non-aqueous electrolyte, and may include lithium difluorophosphate (LiDFP), LiPO2F2, or LiBF4. Among these other electrolyte additives, when a combination of vinylene carbonate (VC), ethylene sulfate (Esa), and lithium difluorophosphate (LiDFP) is additionally included, a more robust SEI film can be formed on the surface of the negative electrode during the initial activation process of the secondary battery, and gas generation that may be generated due to decomposition of the electrolyte at high temperatures can be suppressed, thereby improving the high-temperature stability of the secondary battery. Meanwhile, two or more of the above other electrolyte additives may be mixed and used, and may be included in an amount of 0.01 to 30 wt%, specifically 0.1 to 25 wt%, and preferably 1 to 20 wt%, based on the total weight of the non-aqueous electrolyte. When the content of the above other electrolyte additives satisfies the above range, the effect of improving ion conductivity and cycle characteristics is more excellent. Lithium secondary battery The present invention also provides a lithium secondary battery comprising the non-aqueous electrolyte. Specifically, the lithium secondary battery includes a cathode including a cathode active material, an anode including a cathode active material, a separator interposed between the cathode and the anode, and the non-aqueous electrolyte described above. At this time, the lithium secondary battery of the present invention can be manufactured according to a conventional method known in the art. For example, the electrode assembly can be formed by sequentially stacking a cathode, an anode, and a separator between the cathode and the anode, and then inserting the electrode assembly into a battery case and injecting a non-aqueous electrolyte according to the present invention. (1) Bipolar The above positive electrode can be manufactured by coating a positive electrode mixture slurry including a positive electrode active material, a binder, a conductive agent, and a solvent on a positive electrode current collector. The above 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. can be used. The above cathode active material is a compound capable of reversible intercalation and deintercalation of lithium, and specifically may include a lithium metal oxide containing lithium and one or more metals such as cobalt, manganese, nickel or aluminum. More specifically, the lithium metal oxide may be 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(here, 0 <Y<1), LiMn 2-Z Ni Z O4 (wherein, 0<Z<2) etc.), lithium-nickel-cobalt oxides (e.g., LiNi 1-Y1 Co Y1 O2(here, 0 <Y1<1) 등), 리튬-망간-코발트계 산화물(예를 들면, LiCo 1-Y2 Mn Y2 O2(here, 0 <Y2<1), LiMn 2-Z1 Co Z1 O4 (wherein, 0<Z1<2) etc.), lithium-nickel-manganese-cobalt oxides (e.g., Li(Ni p Co q Mn r )O2(where, 0<p<1, 0<q<1, 0<r<1, p+q+r=1) or Li(Ni p1 Co q1 Mn r1 )O4 (wherein, 0<p1<2, 0<q1<2, 0<r1<2, p1+q1+r1=2) etc.), or lithium-nickel-cobalt-transition metal (M) oxide (e.g., Li(Ni p2 Co q2 Mn r2 M s2)O2 (wherein, M is selected from the group consisting of Al, Fe, V, Cr, Ti, Ta, Mg, and Mo, and p2, q2, r2, and s2 are atomic fractions of independent elements, respectively, such that 0<p2<1, 0<q2<1, 0<r2<1, 0<s2<1, p2+q2+r2+s2=1), etc.), and one or more compounds of these may be included. Among these, the lithium metal oxides are LiCoO2, LiMnO2, LiNiO2, lithium nickel manganese cobalt oxide (e.g., Li(Ni)) in that they can improve the capacity characteristics and stability of the battery. 1 / 3 Mn 1 / 3 Co 1 / 3 )O2, Li(Ni 0.6 Mn 0.2 Co 0.2 )O2, Li(Ni) 0.5 Mn 0.3 Co 0.2 )O2, Li(Ni 0.7 Mn 0.15 Co 0.15 )O2 and Li(Ni 0.8 Mn 0.1 Co 0.1 )O2, etc.), or lithium nickel cobalt aluminum oxide (e.g., Li(Ni 0.8 Co 0.15 Al 0.05 )O2, etc.), and one or a mixture of two or more of these may be used. Among these, a cathode active material having a nickel content of 80 atm% or more can be used in that it can maximize the capacity characteristics of the battery. For example, the lithium transition metal oxide can include one represented by the following [chemical formula 2]. [Chemical formula 2] Li x Ni a Co b M 1 c M 2 d O2 In the above chemical formula 2, the M 1 is at least one selected from Mn and Al, and preferably may be Mn or a combination of Mn and Al. M 2 may be at least one selected from the group consisting of Zr, B, W, Mg, Ce, Hf, Ta, La, Ti, Sr, Ba, F, P, and S. The above x represents the atomic fraction of lithium in the lithium transition metal oxide, and may be 0.90≤x≤1.1, preferably 0.95≤x≤1.08, and more preferably 1.0≤x≤1.08. The above a represents the atomic fraction of nickel among the metal elements excluding lithium in the lithium transition metal oxide, and may be 0.60≤a<1.0, 0.80≤a<1.0, preferably 0.80≤a≤0.95, and more preferably 0.80≤a≤0.90. When the nickel content satisfies the above range, high-capacity characteristics can be implemented. The above b represents the atomic fraction of cobalt among the metal elements excluding lithium in the lithium transition metal oxide, and is 0. <b<0.4, 0<b<0.2, 0<b≤0.15, 또는 0.01≤b≤0.10일 수 있다. The above c is M among the metal elements excluding lithium in the lithium transition metal oxide. 1 It represents the atomic fraction of , 0 <c<0.4, 0<c<0.2, 0<c≤0.15, 또는 0.01≤c≤0.10일 수 있다. The above d is M among the metal elements excluding lithium in the lithium transition metal oxide. 2 It represents the atomic fraction of , and can be 0≤d≤0.1, or 0≤d≤0.05. The above positive electrode active material may be included in an amount of 60 to 99 wt%, preferably 70 to 99 wt%, and more preferably 80 to 98 wt%, based on the total weight of solids excluding the solvent in the positive electrode mixture slurry. The above binder is a component that assists in the bonding of active materials and conductive materials and bonding to a current collector. Examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl pyrrolidone, polytetrafluoroethylene, polyethylene (PE), polypropylene, ethylene-propylene-diene monomer, sulfonated ethylene-propylene-diene monomer, styrene-butadiene rubber, fluororubber, and various copolymers. Typically, the binder may be included in an amount of 1 to 20 wt%, preferably 1 to 15 wt%, and more preferably 1 to 10 wt%, based on the total weight of solids excluding the solvent in the positive electrode mixture slurry. The conductive agent is a component for further improving the conductivity of the positive electrode active material, and can be added in an amount of 1 to 20 wt% based on the total weight of the solid content in the positive electrode mixture slurry. The conductive agent is not particularly limited as long as it has conductivity without causing a chemical change in the battery, and for example, carbon powder such as carbon black, acetylene 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; fluorinated carbon powder; conductive powder such as aluminum powder or nickel powder; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; conductive materials such as polyphenylene derivatives, etc. can be used. Typically, the above-mentioned conductive agent may be included in an amount of 1 to 20 wt%, preferably 1 to 15 wt%, and more preferably 1 to 10 wt%, based on the total weight of solids in the positive electrode mixture slurry excluding the solvent. The solvent may include an organic solvent such as NMP (N-methyl-2-pyrrolidone), and may be used in an amount that provides a desirable viscosity when including the positive electrode active material, and optionally a binder and a conductive material. For example, the concentration of the solid content including the positive electrode active material, and optionally a binder and a conductive material may be 50 to 95 wt%, preferably 70 to 95 wt%, and more preferably 70 to 90 wt%. (2) Cathode The above negative electrode can be manufactured, for example, by coating a negative electrode composite slurry containing a negative electrode active material, a binder, a conductive agent, and a solvent on a negative electrode current collector, or a graphite electrode made of carbon (C) or the metal itself can be used as the negative electrode. For example, when manufacturing a negative electrode by coating a negative electrode composite slurry on the negative electrode current collector, the negative electrode current collector generally has a thickness of 3 to 500 μm. The negative electrode current collector is not particularly limited as long as it has high conductivity without causing a chemical change in the battery, and for example, copper, stainless steel, aluminum, nickel, titanium, sintered carbon, copper or stainless steel surface-treated with carbon, nickel, titanium, silver, etc., aluminum-cadmium alloy, etc. can be used. In addition, like the positive electrode current collector, the bonding strength of the negative electrode active material can be strengthened by forming fine unevenness on the surface, and 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. In addition, the negative electrode active material may include at least one selected from the group consisting of lithium metal, a carbon material capable of reversibly intercalating / deintercalating lithium ions, a metal or an alloy of these metals and lithium, a metal composite oxide, a material capable of doping and dedoping lithium, and a transition metal oxide. As the carbon material capable of reversibly intercalating / deintercalating the lithium ion, any carbon-based negative electrode active material generally used in lithium ion secondary batteries can be used without particular limitation, and representative examples thereof include crystalline carbon, amorphous carbon, or a combination of these. Examples of the crystalline carbon include graphite such as natural graphite or artificial graphite in an amorphous, plate-like, flake-like, spherical, or fibrous form, and examples of the amorphous carbon include soft carbon (low-temperature calcined carbon) or hard carbon, mesophase pitch carbide, calcined coke, and the like. As the above metal or an alloy of these metals with lithium, a metal selected from the group consisting of Cu, Ni, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al and Sn or an alloy of these metals with lithium can be used. The above metal composite oxides include PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4, Bi2O5, Li. x Fe2O3(0≤x≤1), Li x WO2(0≤x≤1) and Sn x Me 1-x Me' y O z (Me: Mn, Fe, Pb, Ge; Me': Al, B, P, Si, elements of group 1, 2, and 3 of the periodic table, halogens; 0 <x≤1; 1≤y≤3; 1≤z≤8) 로 이루어진 군에서 선택되는 것이 사용될 수 있다. Materials capable of doping and dedoping the above lithium include Si, SiO. x(0 <x≤2), 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), Sn, SnO2, Sn-Y(상기 Y는 알칼리 금속, 알칼리 토금속, 13족 원소, 14족 원소, 전이금속, 희토류 원소 및 이들의 조합으로 이루어진 군에서 선택되는 원소이며, Sn은 아님) 등을 들 수 있고, 또한 이들 중 적어도 하나와 SiO2를 혼합하여 사용할 수도 있다. 상기 원소 Y로는 Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, 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, Ge, P, As, Sb, Bi, S, Se, Te, Po 및 이들의 조합으로 이루어진 군에서 선택될 수 있다. Examples of the above transition metal oxides include lithium-containing titanium composite oxide (LTO), vanadium oxide, and lithium vanadium oxide. The above negative active material may be included in an amount of 60 to 99 wt%, preferably 70 to 99 wt%, and more preferably 80 to 98 wt%, based on the total weight of the solid content in the negative electrode mixture slurry. The above binder is a component that assists in bonding between the conductive material, the active material, and the current collector. Examples of such binders include polyvinylidene fluoride (PVDF), polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl pyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene monomer, sulfonated ethylene-propylene-diene monomer, styrene-butadiene rubber, fluororubber, various copolymers thereof, and the like. Typically, the binder may be included in an amount of 1 to 20 wt%, preferably 1 to 15 wt%, and more preferably 1 to 10 wt%, based on the total weight of solids excluding the solvent in the negative electrode composite slurry. The conductive agent is a component for further improving the conductivity of the negative active material, and can be added in an amount of 1 to 20 wt% based on the total weight of the solid content in the negative electrode mixture slurry. The conductive agent is not particularly limited as long as it has conductivity without causing a chemical change in the battery, and for example, carbon powder such as carbon black, acetylene 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; fluorinated carbon powder; conductive powder such as aluminum powder or nickel powder; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; conductive materials such as polyphenylene derivatives, etc. can be used. The above-mentioned challenging agent may be included in an amount of 1 to 20 wt%, preferably 1 to 15 wt%, and more preferably 1 to 10 wt%, based on the total weight of solids excluding the solvent in the negative electrode composite slurry. The solvent may include water or an organic solvent such as NMP (N-methyl-2-pyrrolidone), and may be used in an amount that provides a desirable viscosity when including the negative active material, and optionally a binder and a conductive material. For example, the concentration of the solid content including the negative active material, and optionally a binder and a conductive material may be included to be 50 wt% to 95 wt%, preferably 70 wt% to 90 wt%. When using the metal itself as the above cathode, it can be manufactured by physically bonding, rolling, or depositing the metal onto the metal thin film itself or on the cathode current collector. The deposition method can use an electrical deposition method or a chemical vapor deposition method. For example, the metal film itself or the metal bonded / rolled / deposited on the negative electrode current collector may include one metal or an alloy of two metals selected from the group consisting of lithium (Li), nickel (Ni), tin (Sn), copper (Cu), and indium (In). (3) Membrane In addition, as a separator, a conventional porous polymer film that has been conventionally used as a separator, for example, a porous polymer film made of a polyolefin polymer such as ethylene homopolymer, propylene homopolymer, ethylene / butene copolymer, ethylene / hexene copolymer, and ethylene / methacrylate copolymer, may be used alone or in a laminated manner, or a conventional porous nonwoven fabric, for example, a nonwoven fabric made of high-melting-point glass fiber, polyethylene terephthalate fiber, etc. may be used, but is not limited thereto. 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. There is no particular limitation on the external shape of the lithium secondary battery of the present invention, but it may be in the shape of a cylinder, a square, a pouch, or a coin using a can. Hereinafter, the present invention will be described in more detail through specific examples. However, the following examples are merely examples to help understand the present invention and do not limit the scope of the present invention. It will be obvious to those skilled in the art that various changes and modifications are possible within the scope and technical idea of ​​the present description, and it is natural that such changes and modifications fall within the scope of the appended patent claims. Example Example 1 (Manufacture of non-aqueous electrolyte) LiPF6 was dissolved in an organic solvent (ethylene carbonate (EC): ethyl methyl carbonate (EMC): = 30:70 volume ratio) to make a non-aqueous solvent at a concentration of 1.3 M and vinylene carbonate (VC) at a concentration of 0.5 wt%, and 0.5 g of a compound of the following chemical formula 1-2a was added to 99.5 g of the non-aqueous solvent to make a non-aqueous electrolyte. [Chemical Formula 1-2a] (Lithium secondary battery manufacturing) Cathode active material (LiNi 0.8 Co 0.1 Mn 0.1 O2), a conductive agent (carbon nanotube), and a binder (polyvinylidene fluoride) were added to a solvent, N-methyl-2-pyrrolidone (NMP), in a weight ratio of 97.74:0.70:1.56 to prepare a cathode slurry (solid content 60 wt%). The cathode slurry was applied to one surface of a cathode current collector (Al thin film) having a thickness of 12 ㎛, and dried and roll pressed to prepare a cathode. A negative electrode slurry (solid content 40 wt%) was prepared by adding a negative electrode active material (graphite), a negative electrode active material (SiO), a conductive agent (carbon black), and a binder (styrene-butadiene rubber) to a solvent, H2O, in a weight ratio of 93.8:5.0:0.3:0.9. The negative electrode slurry was applied to one surface of a negative electrode current collector (Cu thin film) having a thickness of 8 ㎛, and drying and roll pressing were performed to prepare a negative electrode. A polyethylene separator was interposed between the positive and negative electrodes manufactured above in a dry room, and then the non-aqueous electrolyte manufactured above was injected to manufacture a secondary battery. Example 2 A secondary battery was manufactured in the same manner as in Example 1, except that 1.0 g of the compound of Chemical Formula 1-2a was added to 99.0 g of the non-aqueous solvent manufactured in Example 1 to manufacture a non-aqueous electrolyte. Example 3 A secondary battery was manufactured in the same manner as in Example 1, except that 1.0 g of a compound of the following chemical formula 1-2c was added to 99.0 g of the non-aqueous solvent manufactured in Example 1 to manufacture a non-aqueous electrolyte. [Chemical formula 1-2c] Example 4 A secondary battery was manufactured in the same manner as in Example 1, except that 3.0 g of the compound of Chemical Formula 1-2a was added to 97.0 g of the non-aqueous solvent manufactured in Example 1 to manufacture a non-aqueous electrolyte. Example 5 A secondary battery was manufactured in the same manner as in Example 1, except that 5.0 g of the compound of Chemical Formula 1-2a was added to 95.0 g of the non-aqueous solvent manufactured in Example 1 to manufacture a non-aqueous electrolyte. Comparative Example 1 A secondary battery was manufactured in the same manner as in Example 1, except that a non-aqueous electrolyte was manufactured using 100 g of the non-aqueous solvent manufactured in Example 1. Comparative Example 2 A secondary battery was manufactured in the same manner as in Example 1, except that 0.5 g of a compound of the following chemical formula A was added to 99.5 g of the non-aqueous solvent manufactured in Example 1 to manufacture a non-aqueous electrolyte. [Chemical Formula A] Experimental Example 1 - Evaluation of High Temperature Cycle Characteristics For each of the secondary batteries manufactured in Examples 1 to 5 and Comparative Examples 1 and 2, cycle characteristics were evaluated. Specifically, each of the batteries manufactured in Examples 1 to 5 and Comparative Examples 1 and 2 was charged to 4.3 V at 45°C with a 1.0 C constant current, charged to 1 / 20 C with a constant voltage, and then discharged to 2.5 V at a 1.0 C constant current, which was considered one cycle, and then 100 charge / discharge cycles were performed, and the resistance increase rate after 100 cycles compared to the initial resistance was measured. The results are shown in Table 1 below. Resistance Increase Rate (%)Example 113.4%Example 28.3%Example 310.2%Example 411.8%Example 512.9%Comparative Example 116.4%Comparative Example 215.3% As shown in Table 1, Examples 1 to 5 using the non-aqueous electrolyte additive of the present invention had lower resistance increase rates and superior life characteristics than Comparative Example 1 that did not use the additive. In addition, compared to the additive of Chemical Formula 1 of the present invention in which -OC≡CH is substituted at carbon 1 of the propane sultone ring, the film formed on the surface of the anode in the case of the compound of Chemical Formula A of Comparative Example 2 is thought to be less solid. For this reason, the film formed by the compound of Chemical Formula A is thought to have a lower resistance increase rate because it undergoes more oxidative decomposition on the surface of the anode. Experimental Example 2 - Evaluation of High Temperature Storage Characteristics For each of the secondary batteries manufactured in Examples 1 to 5 and Comparative Examples 1 and 2, high-temperature storage characteristics were evaluated. Specifically, the secondary batteries of Examples 1 to 5 and Comparative Examples 1 and 2 were each charged to 4.3 V and then stored at 60°C for 4 weeks. Before preservation, the volume of the fully charged secondary battery was measured and set as the initial volume of the secondary battery. After 4 weeks, the volume of the preserved secondary battery was measured again to calculate the volume increase during the 4-week storage period. The percentage ratio of the increased volume to the initial volume of the secondary battery was calculated to derive the volume increase rate after 4 weeks. The results are shown in Table 2 below. Volume Increase Rate (%)Example 19.2%Example 27.2%Example 36.9%Example 46.3%Example 54.4%Comparative Example 112.8%Comparative Example 210.6% As shown in Table 2 above, the secondary batteries of Examples 1 to 5 had a smaller volume increase rate after 4 weeks and thus generated less gas at high temperatures compared to the secondary battery of Comparative Example 1 that did not use the additive. In addition, compared to the additive of Chemical Formula 1 of the present invention in which -OC≡CH is substituted at the 1st carbon of the propane sultone ring, the film formed on the surface of the positive electrode of the compound of Chemical Formula A of Comparative Example 2 is thought to be less solid. For this reason, it is thought that the film formed by the compound of Chemical Formula A is easily decomposed when stored at high temperatures, which increases side reactions and thus increases the amount of gas generated.

Claims

1. Lithium salt; organic solvent; and A non-aqueous electrolyte comprising a compound represented by the following chemical formula 1: [Chemical Formula 1] In the above chemical formula 1, R1 and R2 are each independently any one selected from the group consisting of H, -OC≡CH, F, a nitrile group, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, and an alkynyl group having 2 to 10 carbon atoms.

2. In claim 1, The compound of the above chemical formula 1 is a non-aqueous electrolyte selected from the group consisting of additives for non-aqueous electrolytes represented by the following chemical formulas 1-2a to 1-2e. [Chemical Formula 1-2a] [Chemical Formula 1-2b] [Chemical formula 1-2c] [Chemical formula 1-2d] [Chemical Formula 1-2e] 3. In claim 1, A non-aqueous electrolyte, wherein the compound of the above chemical formula 1 is contained in an amount of 0.01 to 10 parts by weight per 100 parts by weight of the non-aqueous electrolyte.

4. In claim 1, A non-aqueous electrolyte wherein the lithium salt is included in a concentration of 0.5 M to 2.0 M.

5. In claim 1, The above lithium salts are LiCl, LiBr, LiI, LiBF4, LiClO4, LiB 10 Cl 10 A non-aqueous electrolyte comprising at least one selected from the group consisting of LiAlCl4, LiAlO2, LiPF6, LiCF3SO3, LiCH3CO2, LiCF3CO2, LiAsF6, LiSbF6, LiCH3SO3, LiN(SO2F)2, LiN(SO2CF2CF3)2, and LiN(SO2CF3)2.

6. In claim 1, A non-aqueous electrolyte comprising at least one organic solvent selected from the group consisting of a cyclic carbonate-based organic solvent, a linear carbonate-based organic solvent, a linear ester-based organic solvent, and a cyclic ester-based organic solvent.

7. In claim 1, A non-aqueous electrolyte further comprising at least one compound selected from the group consisting of cyclic carbonate compounds, halogen-substituted carbonate compounds, sultone compounds, sulfate compounds, phosphate compounds, borate compounds, nitrile compounds, benzene compounds, amine compounds, silane compounds, and lithium salt compounds as an additive.

8. Bipolar; cathode; and A lithium secondary battery comprising a non-aqueous electrolyte according to any one of claims 1 to 7.

9. In claim 8, A lithium secondary battery, wherein the positive electrode is a lithium nickel-based oxide represented by the following [chemical formula 2] as a positive electrode active material. [Chemical formula 2] Li x Ni a Co b M 1 c M 2 d O2 In the above chemical formula 2, M 1 is Mn, Al or a combination of these, and M 2 is at least one selected from the group consisting of Zr, W, Y, Ba, Ca, Ti, Mg, Ta and Nb, and 0.8≤x≤1.2, 0.6≤a<1, 0 <b<0.4, 0<c<0.4, 0≤d≤0.1임.

10. In claim 8, The above negative electrode is SiO as a negative electrode active material. x A lithium secondary battery comprising (0≤x<2).

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