Non-aqueous electrolytes and lithium secondary batteries containing them

Abstract

The present invention relates to a non-aqueous electrolyte comprising a lithium salt, an organic solvent, and an additive, wherein the additive comprises a compound represented by the following chemical formula 1. [Chemical formula 1] JPEG2026511709000066.jpg60170 In the above chemical formula 1, R1 is an allyl group or a propagyl group, R2, R3, R4, and R5 are independently selected from hydrogen and C1-C5 alkyl groups, L is selected from a single bond and an alkylene group having C1-C10, and X is selected from -C(=O)-, -S(=O)-, and -S(=O)2-.

Description

[Technical Field]

[0001] This invention relates to a non-aqueous electrolyte and a lithium secondary battery containing the same. [Background technology]

[0002] With the development of the information society, personal IT devices and computer networks have advanced, and consequently, society as a whole has become more dependent on electrical energy. Therefore, there is a need to develop technologies for efficiently storing and utilizing electrical energy.

[0003] Rechargeable batteries are the most suitable technology for a wide range of applications among the technologies currently under development. Among these rechargeable batteries, there is growing interest in lithium-ion batteries, which not only can be miniaturized to a degree suitable for personal IT devices, but also have the highest energy density.

[0004] Typically, lithium-ion batteries are manufactured by injecting or impregnating an electrode assembly, consisting of a positive electrode, a negative electrode, and a porous separator, with a non-aqueous electrolyte.

[0005] For the positive electrode active material of such lithium secondary batteries, the use of lithium-containing cobalt oxide, layered crystalline LiMnO2, spinel crystalline LiMn2O4, lithium-containing nickel oxide (LiNiO2), and lithium nickel-cobalt-manganese transition metal oxide is being considered. On the other hand, for the negative electrode active material, the use of carbon-based active materials and silicon-based active materials is being considered.

[0006] In particular, high capacity, high output, and long lifespan are important characteristics for lithium secondary batteries used in automobiles. To increase the capacity of lithium secondary batteries, methods such as using a positive electrode active material with a high nickel content, which has high energy density but low stability, or driving lithium secondary batteries at high voltages are being considered.

[0007] However, when a lithium secondary battery is powered under the above conditions, as charging and discharging progresses, side reactions caused by electrolyte degradation can degrade the coating or electrode surface structure formed on the positive / negative electrode surfaces, potentially leading to the elution of transition metal ions from the positive electrode surface. These eluted transition metal ions then electro-deposit onto the negative electrode, reducing the passivation capacity of the negative electrode's SEI (Solid Electrolyte Interface) coating, resulting in the degradation of the negative electrode. This degradation phenomenon in secondary batteries tends to accelerate further when the positive electrode potential increases or when the battery is exposed to high temperatures.

[0008] Furthermore, when lithium secondary batteries are used continuously for long periods or left at high temperatures, gas is generated, causing the battery to swell, a phenomenon known as swelling. The amount of gas generated at this time is known to depend on the state of the SEI (Single Energy Intake).

[0009] Therefore, in order to solve these problems, research and development are being attempted on methods that can suppress the elution of metal ions at the positive electrode, form a stable SEI film at the negative electrode, reduce the swelling phenomenon of lithium secondary batteries, and improve stability at high temperatures. [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] One objective of the present invention is to provide a non-aqueous electrolyte that can form a highly durable SEI film on the negative electrode.

[0011] Another objective of the present invention is to provide a lithium secondary battery that includes the aforementioned non-aqueous electrolyte, has improved high-temperature cycling characteristics and high-temperature storage performance, and exhibits enhanced overall performance. [Means for solving the problem]

[0012] [1] The present invention provides a non-aqueous electrolyte comprising a lithium salt, an organic solvent, and an additive, wherein the additive comprises a compound represented by the following chemical formula 1.

[0013] [Chemical formula 1] [ka]

[0014] In the above chemical formula 1, R1 is an allyl group or a propagyl group, R2, R3, R4, and R5 are independently selected from hydrogen and an alkyl group having 1 to 5 carbon atoms, L is selected from a single bond and an alkylene group having 1 to 10 carbon atoms, and X is selected from -C(=O)-, -S(=O)-, and -S(=O)2-.

[0015] [2] The present invention provides the non-aqueous electrolyte described in [1], wherein R1 is an allyl group.

[0016] [3] The present invention provides a non-aqueous electrolyte according to [1] or [2], wherein X is selected from -C(=O)- and -S(=O)-.

[0017] [4] The present invention provides a nonaqueous electrolyte according to any one of [1] to [3] above, wherein R2, R3, R4, and R5 are independently alkyl groups having 1 to 5 carbon atoms.

[0018] [5] The present invention provides a non-aqueous electrolyte according to any one of [1] to [4] above, wherein the compound represented by chemical formula 1 comprises at least one selected from the group consisting of compounds represented by the following chemical formulas: chemical formula 1-A, chemical formula 1-B, chemical formula 1-C, chemical formula 2-A, chemical formula 2-B, and chemical formula 2-C.

[0019] [Chemical formula 1-A] [ka]

[0020] [Chemical formula 1-B] [ka]

[0021] [Chemical formula 1-C] [ka]

[0022] [Chemical formula 2-A] [ka]

[0023] [Chemical formula 2-B] [ka]

[0024] [Chemical formula 2-C] [ka]

[0025] In the aforementioned chemical formulas 1-A, 1-B, 1-C, 2-A, 2-B, and 2-C, R2, R3, R4, and R5 are defined as in the aforementioned chemical formula 1.

[0026] [6] The present invention provides a non-aqueous electrolyte according to any one of [1] to [5] above, wherein the compound represented by chemical formula 1 includes at least one selected from the group consisting of compounds represented by the following chemical formulas: 1-A-1, 1-A-2, 1-B-1, 1-B-2, 1-C-1, 1-C-2, 2-A-1, 2-A-2, 2-B-1, 2-B-2, 2-C-1, and 2-C-2.

[0027] [Chemical formula 1-A-1] [ka]

[0028] [Chemical Formula 1-A-2]

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[0029] [Chemical Formula 1-B-1]

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[0030] [Chemical Formula 1-B-2]

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[0031] [Chemical formula 1-C-1]

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[0032] [Chemical formula 1-C-2]

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[0033] [Chemical Formula 2-A-1]

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[0034] [Chemical formula 2-A-2]

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[0035] [Chemical Formula 2-B-1]

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[0036] [Chemical formula 2-B-2] [ka]

[0037] [Chemical formula 2-C-1] [ka]

[0038] [Chemical formula 2-C-2] [ka]

[0039] [7] The present invention provides a nonaqueous electrolyte according to any one of [1] to [6] above, wherein the compound represented by chemical formula 1 is contained in an amount of 0.01% to 10% by weight based on the weight of the nonaqueous electrolyte.

[0040] [8] The present invention relates to the lithium salt being LiCl, LiBr, LiI, LiBF4, LiClO4, LiAlO4, LiAlCl4, LiPF6, LiSbF6, LiAsF6, LiB 10 Cl 10 The present invention provides a non-aqueous electrolyte according to any one of [1] to [7] above, comprising at least one selected from the group consisting of LiBOB(LiB(C2O4)2), LiCF3SO3, LiFSi(LiN(SO2F)2), LiCH3SO3, LiCF3CO2, LiCH3CO2, and LiBETI(LiN(SO2CF2CF3)2).

[0041] [9] The present invention provides a nonaqueous electrolyte according to any one of [1] to [8], wherein the lithium salt is contained in the nonaqueous electrolyte at a molar concentration of 0.5 M to 5.0 M.

[0042]

[10] The present invention provides a non-aqueous electrolyte according to any one of [1] to [9] above, wherein the organic solvent comprises at least one selected from the group consisting of cyclic carbonate organic solvents, linear carbonate organic solvents, linear ester organic solvents, and cyclic ester organic solvents.

[0043]

[11] The present invention provides a lithium secondary battery comprising a positive electrode, a negative electrode opposite to the positive electrode, a separator interposed between the positive electrode and the negative electrode, and a non-aqueous electrolyte according to at least one of [1] to

[10] . [Effects of the Invention]

[0044] The non-aqueous electrolyte of the present invention is characterized by using a cyclic borate compound containing an allyl group or a propagyl group in its structure as an additive. The cyclic borate compound according to the present invention is dense while promoting lithium transport characteristics when reduced at the negative electrode, thus enabling the formation of a highly durable SEI film. In this case, the allyl group or propagyl group contained in the cyclic borate compound facilitates the approach of the cyclic borate compound to the negative electrode during reduction at the negative electrode, thereby improving reactivity, and thus the SEI film derived from the cyclic borate compound is formed more easily. As a result, lithium secondary batteries containing the non-aqueous electrolyte according to the present invention can have improved lifespan and storage performance, particularly at high temperatures and high voltages. [Modes for carrying out the invention]

[0045] The terms and words used in this specification and in the claims should not be interpreted in a manner limited to their general or dictionary meanings, but rather in a manner consistent with the technical idea of ​​the present invention, in accordance with the principle that inventors may appropriately define the concepts of terms in order to best describe their invention.

[0046] In this specification, terms such as “includes,” “equip,” or “have” are intended to specify the presence of implemented features, figures, steps, components, or combinations thereof, and should be understood not to preemptively exclude the presence or possibility of adding one or more other features, figures, steps, components, or combinations thereof.

[0047] On the other hand, before describing the present invention, unless otherwise specifically mentioned in the present invention, "*" means a connected portion (bonding site) between identical or different atoms or the terminal parts of a chemical formula.

[0048] Furthermore, in this specification, when "a to b carbon atoms" is mentioned, "a" and "b" refer to the number of carbon atoms contained in a specific functional group. That is, the functional group may contain "a" to "b" carbon atoms. For example, "alkyl group with 1 to 5 carbon atoms" means alkyl groups containing 1 to 5 carbon atoms, i.e., CH3-, CH3CH2-, CH3CH2CH2-, (CH3)2CH-, CH3CH2CH2CH2-, (CH3)2CHCH2-, CH3CH2CH2CH2CH2-, (CH3)2CHCH2CH2-, etc.

[0049] Furthermore, in this specification, alkyl groups or aryl groups may or may not be substituted. Unless otherwise defined, "substitution" means that at least one hydrogen bonded to a carbon is replaced by an element other than hydrogen, for example, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkyl group having 3 to 12 carbon atoms, an alkenyl group having 3 to 12 carbon atoms, an alkynyl group having 3 to 12 carbon atoms, an heterocycloalkyl group having 3 to 12 carbon atoms, an heterocycloalkenyl group having 3 to 12 carbon atoms, an heterocycloalkynyl group having 2 to 12 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, a halogen atom, a fluoroalkyl group having 1 to 20 carbon atoms, a nitro group having 6 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, a heteroaryl group having 2 to 20 carbon atoms, or a haloaryl group having 6 to 20 carbon atoms.

[0050] The present invention will be described in more detail below.

[0051] The non-aqueous electrolyte and / or lithium secondary battery according to the present invention includes at least one or more of the configurations disclosed below, and can include any combination among the technically possible configurations of the following configurations.

[0052] Non-aqueous electrolytes The present invention relates to a non-aqueous electrolyte.

[0053] Specifically, the non-aqueous electrolyte according to the present invention provides a non-aqueous electrolyte containing a lithium salt, an organic solvent, and an additive, and the additive contains a compound represented by the following Chemical Formula 1.

[0054] [Chemical Formula 1] [Chemical Structure]

[0055] In Chemical Formula 1, R1 is an allyl group or a propargyl group, R2, R3, R4, and R5 are each independently selected from hydrogen and an alkyl group having 1 to 5 carbon atoms, L is selected from a single bond and an alkylene group having 1 to 10 carbon atoms, and X is selected from -C(=O)-, -S(=O)-, and -S(=O)2-.

[0056] (1) Lithium salt As the lithium salt used in the present invention, various lithium salts commonly used in non-aqueous electrolytes for lithium secondary batteries can be used without limitation. For example, the lithium salt contains Li as a cation + and, as an anion, F - , Cl - , Br - , I - , NO3 - , N(CN)2 - , BF4 - , ClO4 - , AlO4 - , AlCl4 - , PF6 - , SbF6 - , AsF6 - , B 10 Cl10 - BF2C2O4 - BC4O8 - PF4C2O4 - PF2C4O8 - (CF3)2PF4 - (CF3)3PF3 - (CF3)4PF2 - (CF3)5PF - (CF3)6P - CF3SO3 - , C4F9SO3 - CF3CF2SO3 - , (FSO2)2N - CF3CF2(CF3)2CO - (CF3SO2) 2CH - CH3SO3 - CF3(CF2)7SO3 - CF3CO2 - CH3CO2 - SCN - , and (CF3CF2SO2)2N - It may include at least one selected from the group consisting of the following.

[0057] Specifically, the lithium salts are LiCl, LiBr, LiI, LiBF4, LiClO4, LiAlO4, LiAlCl4, LiPF6, LiSbF6, LiAsF6, LiB 10 Cl 10 The lithium salt may include at least one selected from the group consisting of LiBOB(LiB(C2O4)2), LiCF3SO3, LiFSI(LiN(SO2F)2), LiCH3SO3, LiCF3CO2, LiCH3CO2, and LiBETI(LiN(SO2CF2CF3)2). Specifically, the lithium salt may include at least one selected from the group consisting of LiBF4, LiClO4, LiPF6, LiBOB(LiB(C2O4)2), LiCF3SO3, LiTFSI(LiN(SO2CF3)2), LiFSI((LiN(SO2F)2), and LiBETI(LiN(SO2CF2CF3)2).

[0058] The lithium salt may be included in the non-aqueous electrolyte at a concentration of 0.5 M to 5 M, specifically 0.8 M to 4 M, more specifically 0.8 M to 2.0 M. When the concentration of the lithium salt satisfies the above range, the lithium ion transport number (Li + The transference number and the degree of lithium ion dissociation are improved, which can enhance the battery's output characteristics.

[0059] (2) Organic solvents The aforementioned organic solvent is not particularly limited as long as it is a non-aqueous solvent commonly used in lithium secondary batteries, and its decomposition due to oxidation reactions during the charging and discharging process of the secondary battery is minimized.

[0060] Specifically, the organic solvent may include at least one selected from the group consisting of cyclic carbonate organic solvents, linear carbonate organic solvents, linear ester organic solvents, and cyclic ester organic solvents.

[0061] Specifically, the organic solvent may include a cyclic carbonate organic solvent, a linear carbonate organic solvent, or a mixture thereof.

[0062] The cyclic carbonate-based organic solvent is a highly viscous organic solvent with a high dielectric constant that readily dissociates lithium salts in electrolytes. Specifically, it may contain at least one organic solvent selected from the group consisting of ethylene carbonate (EC), fluoroethylene carbonate (FEC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate, and vinylene carbonate. More specifically, it may contain at least one selected from the group consisting of ethylene carbonate (EC) and fluoroethylene carbonate (FEC).

[0063] Furthermore, the linear carbonate-based organic solvent is an organic solvent having low viscosity and low dielectric constant, and may specifically include at least one 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 more specifically, may include at least one selected from the group consisting of ethyl methyl carbonate (EMC) and diethyl carbonate (DEC).

[0064] The organic solvent may be a mixture of a cyclic carbonate organic solvent and a linear carbonate organic solvent. In this case, the cyclic carbonate organic solvent and the linear carbonate organic solvent may be mixed in a volume ratio of 5:95 to 40:60, specifically, in a volume ratio of 7:93 to 25:75. When the mixing ratio of the cyclic carbonate organic solvent and the linear carbonate organic solvent satisfies the above range, both high dielectric constant and low viscosity characteristics can be achieved, resulting in excellent ionic conductivity.

[0065] Furthermore, in order to produce an electrolyte having high ionic conductivity, the organic solvent may further contain at least one ester-based organic solvent selected from the group consisting of linear ester-based organic solvents and cyclic ester-based organic solvents, in addition to at least one carbonate-based organic solvent selected from the group consisting of cyclic carbonate-based organic solvents and linear carbonate-based organic solvents.

[0066] The linear ester organic solvent may specifically include at least one selected from the group consisting of methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, and butyl propionate.

[0067] Furthermore, the cyclic ester organic solvent may specifically include at least one selected from the group consisting of γ-butyrolactone, γ-valerolactone, γ-caprolactone, σ-valerolactone, and ε-caprolactone.

[0068] On the other hand, the organic solvent may be further used with any organic solvent commonly used for non-aqueous electrolytes, without limitation, as needed. For example, it may further contain at least one or more organic solvents such as ether-based organic solvents, glyme-based solvents, and nitrile-based organic solvents.

[0069] The ether-based solvent may be 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 of these, but is not limited to these.

[0070] The aforementioned glyme-based solvent is a solvent that has a higher dielectric constant and lower surface tension than linear carbonate-based organic solvents, and has low reactivity with metals. It may include, but is not limited to, at least one selected from the group consisting of dimethoxyethane (glyme, DME), diethoxyethane, diglyme, triglyme, and tetraglyme (TEGDME).

[0071] The nitrile solvent may be one or more selected from the group consisting of acetonitrile, propionitrile, butyronitrile, valeronitrile, caprylonitrile, heptanenitrile, cyclopentanecarbonile, cyclohexanecarbonile, 2-fluorobenzonitrile, 4-fluorobenzonitrile, difluorobenzonitrile, trifluorobenzonitrile, phenylacetonitrile, 2-fluorophenylacetonitrile, and 4-fluorophenylacetonitrile, but is not limited to these.

[0072] (3) Additives The non-aqueous electrolyte contains additives.

[0073] The aforementioned additive contains a compound represented by the following chemical formula 1.

[0074] [Chemical formula 1] [ka]

[0075] In the above chemical formula 1, R1 is an allyl group or a propagyl group, R2, R3, R4, and R5 are independently selected from hydrogen and an alkyl group having 1 to 5 carbon atoms, L is selected from a single bond and an alkylene group having 1 to 10 carbon atoms, and X is selected from -C(=O)-, -S(=O)-, and -S(=O)2-.

[0076] The compound represented by chemical formula 1 is reduced at the negative electrode, exhibits excellent lithium transfer characteristics, and has high density, allowing for the formation of a highly durable SEI coating on the negative electrode.

[0077] Generally, cyclic borates are substances that can be reduced at the negative electrode to form an SEI film. However, after being solvated with an organic solvent, they become excessively bulky, making it difficult to access the negative electrode. This reduced accessibility makes the reaction during reduction at the negative electrode difficult. In this regard, the compound represented by chemical formula 1 according to the present invention is characterized by having an allyl group (-CH2-CH=CH2) or a propagyl group (-CH2-C≡CH) bonded to the cyclic borate in its structure. Because the allyl group or propagyl group has high reactivity and easily accesses the negative electrode due to its LUMO properties, the cyclic borate bonded to the allyl group or propagyl group can also easily access the negative electrode, thereby promoting the reactivity of the cyclic borate at the negative electrode. This effect cannot be achieved with other substituents (such as alkyl groups) other than the allyl group and propagyl group.

[0078] In the above chemical formula 1, R1 may be an allyl group or a propagyl group, and more specifically, an allyl group.

[0079] In the above chemical formula 1, R2, R3, R4, and R5 may be independently selected from hydrogen and C1-C5 alkyl groups, specifically independently from each other they may be C1-C5 alkyl groups, more specifically independently from each other they may be C1-C3 alkyl groups, and even more specifically independently from each other they may be selected from methyl and ethyl groups, and even more specifically they may be methyl groups. With the above types, R2, R3, R4, and R5 can achieve a stable reactivity and excellent durability SEI film formation effect without inhibiting the effect of the combination of cyclic borate and allyl or propagyl group.

[0080] In the above chemical formula 1, L may be selected from a single bond and an alkylene group having 1 to 10 carbon atoms, and when it is within the above range, Allyl The effects of improving the accessibility of the cyclic borate to the negative electrode and enhancing its reactivity can be easily achieved by using a group or propagyl group. In the above chemical formula 1, L may be specifically selected from a single bond and an alkylene group having 1 to 3 carbon atoms, and more specifically, it may be a single bond.

[0081] In the above chemical formula 1, X is selected from -C(=O)-, -S(=O)-, and -S(=O)2-. The above X is a cyclic borate and Allyl The group or propagyl group can be linked to improve lithium transfer characteristics, film durability, and oxidation resistance during SEI film formation. In the above chemical formula 1, X may be specifically selected from -C(=O)- and -S(=O)-.

[0082] Specifically, the compound represented by chemical formula 1 may include at least one compound selected from the group consisting of compounds represented by the following chemical formulas 1-A, 1-B, 1-C, 2-A, 2-B, and 2-C. More specifically, the compound represented by chemical formula 1 may include at least one compound selected from the group consisting of compounds represented by the following chemical formulas 1-A, 1-B, and 1-C. Even more specifically, the compound represented by chemical formula 1 may include at least one compound selected from the group consisting of compounds represented by the following chemical formulas 1-A and 1-B.

[0083] [Chemical formula 1-A] [ka]

[0084] [Chemical formula 1-B] [ka]

[0085] [Chemical formula 1-C] [ka]

[0086] [Chemical formula 2-A] [ka]

[0087] [Chemical formula 2-B] [ka]

[0088] [Chemical formula 2-C] [ka]

[0089] In the aforementioned chemical formulas 1-A, 1-B, 1-C, 2-A, 2-B, and 2-C, R2, R3, R4, and R5 are defined as in the aforementioned chemical formula 1.

[0090] The compound represented by chemical formula 1 may include at least one selected from the group consisting of compounds represented by the following chemical formulas: 1-A-1, 1-A-2, 1-B-1, 1-B-2, 1-C-1, 1-C-2, 2-A-1, 2-A-2, 2-B-1, 2-B-2, 2-C-1, and 2-C-2. Specifically, the compounds represented by the following chemical formulas: 1-A-1, 1-A-2, 1-B-1, 1- It may include at least one compound selected from the group consisting of compounds represented by chemical formulas B-2, 1-C-1, and 1-C-2, more specifically, it may include at least one compound selected from the group consisting of compounds represented by the following chemical formulas 1-A-1, 1-A-2, 1-B-1, and 1-B-2, and even more specifically, it may include at least one compound selected from the group consisting of compounds represented by the following chemical formulas 1-A-1 and 1-A-2.

[0091] [Chemical formula 1-A-1] [ka]

[0092] [Chemical formula 1-A-2] [ka]

[0093] [Chemical formula 1-B-1] [ka]

[0094] [Chemical formula 1-B-2] [ka]

[0095] [Chemical formula 1-C-1]

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[0096] [Chemical formula 1-C-2]

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[0097] [Chemical Formula 2-A-1]

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[0098] [Chemical formula 2-A-2]

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[0099] [Chemical Formula 2-B-1]

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[0100] [Chemical formula 2-B-2]

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[0101] [Chemical formula 2-C-1]

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[0102] [Chemical formula 2-C-2]

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[0103] The compound represented by chemical formula 1 may be present in an amount of 0.01% to 10% by weight, specifically 0.05% to 5% by weight, or more specifically 2% to 4% by weight, based on the weight of the non-aqueous electrolyte. When the compound represented by chemical formula 1 is used within the above content range, a flexible and highly durable SEI coating can be formed on the negative electrode, and an increase in resistance can be prevented in the event of excessive addition.

[0104] The additive may further include additional additives along with the compound represented by chemical formula 1. These additional additives may be included in the non-aqueous electrolyte to prevent decomposition of the non-aqueous electrolyte and subsequent collapse of the negative electrode in high-power environments, or to provide low-temperature high-rate discharge characteristics, high-temperature stability, overcharge prevention, and suppression of battery swelling at high temperatures.

[0105] Specifically, the additional additives include lithium difluorophosphate (LiDFP), vinylene carbonate, vinyl ethylene carbonate, fluoroethylene carbonate, propane sultone, propene sultone, succinonitrile, adiponitrile, ethylene sulfate, LiBOB (lithium bis-(oxalato)borate), lithium difluorophosphate (LiDFP), TMSPa (tris(trimethylsilyl) phosphate), and TMSPi (tris(trimethylsilyl) phosphite). It may contain at least one selected from the group consisting of phosphates, and specifically may contain lithium difluorophosphate (LiDFP).

[0106] The aforementioned additional additive may be included in the non-aqueous electrolyte in an amount of 0.1% to 15% by weight, more specifically 0.3% to 3% by weight.

[0107] If the non-aqueous electrolyte further contains the additional additive, the weight ratio of the compound represented by chemical formula 1 to the additional additive may be 45:55 to 99:1, specifically 50:50 to 95:5, and more specifically 70:30 to 85:15. When within the above range, the lifespan performance and high-temperature storage performance can be improved to a more favorable level.

[0108] Lithium-ion rechargeable battery Furthermore, the present invention provides a lithium secondary battery containing the aforementioned non-aqueous electrolyte.

[0109] Specifically, the lithium secondary battery according to the present invention includes a positive electrode, a negative electrode facing the positive electrode, a separator interposed between the positive electrode and the negative electrode, and the aforementioned non-aqueous electrolyte.

[0110] The lithium secondary battery can be manufactured by housing an electrode assembly, which includes the positive electrode, a negative electrode facing the positive electrode, and a separator interposed between the positive electrode and the negative electrode, in a battery case, and then injecting the aforementioned non-aqueous electrolyte.

[0111] As explained above, the negative electrode, positive electrode, and separator will be described below.

[0112] (1) Positive electrode The positive electrode may include a positive electrode current collector and a positive electrode active material layer disposed on at least one side of the positive electrode current collector.

[0113] The positive electrode current collector is not particularly limited as long as it does not cause chemical changes in the battery and has high conductivity. Specifically, the positive electrode current collector may contain at least one selected from the group consisting of copper, stainless steel, aluminum, nickel, titanium, calcined carbon, and aluminum-cadmium alloy, preferably aluminum.

[0114] The thickness of the positive electrode current collector is typically between 3 μm and 500 μm.

[0115] The positive electrode current collector is formed by creating fine irregularities on its surface. positive electrode The bonding force of the active material may be strengthened. For example, the positive electrode current collector can be used in various forms such as film, sheet, foil, mesh, porous material, foam, or nonwoven fabric.

[0116] The positive electrode active material layer is disposed on at least one side of the positive electrode current collector. Specifically, the positive electrode active material layer may be disposed on one or both sides of the positive electrode current collector.

[0117] The positive electrode active material layer may contain a positive electrode active material.

[0118] The positive electrode active material is a compound capable of reversible intercalation and deintercalation of lithium. Specifically, it may include a lithium transition metal composite oxide containing at least one transition metal selected from nickel, cobalt, manganese, and aluminum and lithium, preferably a lithium transition metal composite oxide containing a transition metal containing nickel, cobalt, and manganese and lithium.

[0119] For example, as the lithium transition metal composite oxide, there are lithium-manganese-based oxides (e.g., LiMnO2, LiMn2O4, etc.), lithium-cobalt-based oxides (e.g., LiCoO2, etc.), lithium-nickel-based oxides (e.g., LiNiO2, etc.), lithium-nickel-manganese-based oxides (e.g., LiNi 1-Y Mn Y O2 (where 0 < Y < 1), LiMn 2-Z Ni Z O4 (where 0 < Z < 2), etc.), lithium-nickel-cobalt-based oxides (e.g., LiNi 1-Y1 Co Y1 O2 (where 0 < Y1 < 1), etc.), lithium-manganese-cobalt-based oxides (e.g., LiCo 1-Y2 Mn Y2 O2 (where 0 < Y2 < 1), LiMn 2-Z1 Co Z1 O4 (where 0 < Z1 < 2), etc.), lithium-nickel-manganese-cobalt-based oxides (e.g., Li(Ni p Co q Mn r1 )O2 (where 0 < p < 1, 0 < q < 1, 0 < r1 < 1, p + q + r1 = 1) or Li(Ni p1 Co q1 Mn r2 )O4 (where 0 < p1 < 2, 0 < q1 < 2, 0 < r2 < 2, p1 + q1 + r2 = 2), etc.), or lithium-nickel-cobalt-transition metal (M) oxides (e.g., Li(Ni p2 Co q2 Mnr3 M S2 )O₂ (where M is selected from the group consisting of Al, Fe, V, Cr, Ti, Ta, Mg, and Mo, and p₂, q₂, r₃, and s₂ are atomic fractions of independent elements, respectively, where 0 < p₂ < 1, 0 < q₂ < 1, 0 < r₃ < 1, 0 < s₂ < 1, and p₂ + q₂ + r₃ + s₂ = 1), etc.) etc. are included, and one or more of these compounds may be included. Among them, from the viewpoint of enhancing the capacity characteristics and stability of the battery, the lithium transition metal composite oxide is LiCoO₂, LiMnO₂, LiNiO₂, lithium nickel-manganese-cobalt oxide (for example, 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, or Li(Ni 0.8 Mn 0.1 Co 0.1 )O₂, etc.), or lithium nickel cobalt aluminum oxide (for example, Li(Ni 0.8 Co 0.15 Al 0.05 )O₂, etc.), etc. may be, considering the significance of the improvement effect by controlling the types and content ratios of the constituent elements forming the lithium transition metal composite oxide, the lithium transition metal composite oxide is 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, or Li(Ni 0.8 Mn 0.1 Co 0.1 )O₂, etc. may be, and one or more mixtures of these can be used.

[0120] More specifically, the positive electrode active material may be a lithium transition metal composite oxide containing 60 mol% or more nickel based on the total number of moles of transition metal contained in the lithium transition metal composite oxide. Specifically, the positive electrode active material may be a lithium transition metal composite oxide in which the transition metal includes nickel and at least one selected from manganese, cobalt, and aluminum, and the nickel may be contained in an amount of 60 mol% or more, specifically 60 mol% to 90 mol%, based on the total number of moles of transition metal. When such a lithium transition metal composite oxide with a high nickel content is used together with the aforementioned non-aqueous electrolyte, it is preferable because it can reduce by-products in the gas generated by structural collapse.

[0121] Furthermore, the positive electrode active material may contain a lithium composite transition metal oxide represented by the following chemical formula A.

[0122] [Chemical formula A] Li 1+x (Ni a Co b Mn c M d )O2

[0123] In the chemical formula A, M is one or more elements selected from W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo, and 1+x, a, b, c, and d are the atomic fractions of independent elements, where 0≦x≦0.2 and 0.50≦a<1, 0 <b≦0.25、0<c≦0.25、0≦d≦0.1、a+b+c+d=1である。

[0124] Preferably, a, b, c, and d are 0.70 ≤ a ≤ 0.95, 0.025 ≤ b ≤ 0.20, 0.025 ≤ c ≤ 0.20, and 0 ≤ d ≤ 0.05, respectively.

[0125] Furthermore, a, b, c, and d may be 0.80 ≤ a ≤ 0.95, 0.025 ≤ b ≤ 0.15, 0.025 ≤ c ≤ 0.15, and 0 ≤ d ≤ 0.05, respectively.

[0126] Furthermore, a, b, c, and d may be 0.85≦a≦0.90, 0.05≦b≦0.10, 0.05≦c≦0.10, and 0≦d≦0.03, respectively.

[0127] The positive electrode active material may be included in the positive electrode active material layer in an amount of 80% to 99% by weight, preferably 92% to 98.5% by weight, taking into consideration the sufficient capacity of the positive electrode active material.

[0128] The positive electrode active material layer may further include a binder and / or a conductive material along with the positive electrode active material.

[0129] The aforementioned binder is a component that assists in the bonding of the active material to the conductive material and to the current collector, and specifically includes polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, and ethylene-propylene-diene. monomer The material may contain at least one selected from the group consisting of (EPDM), sulfonated EPDM, styrene-butadiene rubber, and fluororubber, preferably polyvinylidene fluoride.

[0130] The binder may be included in the positive electrode active material layer in an amount of 1% to 20% by weight, preferably 1.2% to 10% by weight, from the viewpoint of ensuring sufficient binding force between components such as the positive electrode active material.

[0131] The conductive material is used to assist and improve the conductivity of a secondary battery and is not particularly limited as long as it does not cause chemical changes and is conductive. Specifically, the positive electrode conductive material may contain at least one selected from the group consisting of graphite such as natural graphite or artificial graphite; carbon black such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fibers and metal fibers; conductive tubes such as carbon nanotubes; fluorocarbons; metal powders such as aluminum and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and polyphenylene derivatives, and preferably contains carbon black in order to improve conductivity.

[0132] The conductive material may be included in the positive electrode active material layer in an amount of 1% to 20% by weight, preferably 1.2% to 10% by weight, in order to ensure sufficient electrical conductivity.

[0133] The thickness of the positive electrode active material layer may be 30 μm to 400 μm, preferably 40 μm to 110 μm.

[0134] The positive electrode can be manufactured by coating a positive electrode slurry containing a positive electrode active material and selectively a binder, conductive material, and solvent for forming the positive electrode slurry onto the positive electrode current collector, followed by drying and rolling.

[0135] The solvent for forming the positive electrode slurry may include an organic solvent such as NMP (N-methyl-2-pyrrolidone). The solid content of the positive electrode slurry may be 40% to 90% by weight, specifically 50% to 80% by weight.

[0136] (2) Negative electrode The negative electrode faces the positive electrode.

[0137] The negative electrode may include a negative electrode current collector and a negative electrode active material layer disposed on at least one side of the negative electrode current collector.

[0138] The negative electrode current collector is not particularly limited as long as it does not cause chemical changes in the battery and has high conductivity. Specifically, the negative electrode current collector may be made of copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel with a surface treatment of carbon, nickel, titanium, silver, etc., or aluminum-cadmium alloy.

[0139] The negative electrode current collector typically has a thickness of 3 μm to 500 μm.

[0140] The negative electrode current collector may have its surface textured to enhance the bonding force of the negative electrode active material. For example, the negative electrode current collector can be used in various forms such as film, sheet, foil, mesh, porous material, foam, or nonwoven fabric.

[0141] The negative electrode active material layer is disposed on at least one side of the negative electrode current collector. Specifically, the negative electrode active material layer may be disposed on one or both sides of the negative electrode current collector.

[0142] The aforementioned negative electrode active material layer may contain a negative electrode active material.

[0143] The negative electrode active material is a material capable of reversibly intercalating / deintercalating lithium ions, and may include at least one selected from the group consisting of carbon-based active materials, silicon-based active materials, and lithium metal. More specifically, it may include at least one selected from carbon-based active materials and silicon-based active materials, and more specifically, a silicon-based active material.

[0144] The carbon-based active material may include at least one selected from the group consisting of artificial graphite, natural graphite, hard carbon, soft carbon, carbon black, graphene, and fibrous carbon, and preferably may include at least one selected from the group consisting of artificial graphite and natural graphite.

[0145] The average particle size (D 50 ) of the carbon-based active material may be 10 μm to 30 μm, preferably 15 μm to 25 μm, from the viewpoint of achieving structural stability during charge and discharge and reducing side reactions with the electrolyte.

[0146] The silicon-based active material may include at least one selected from compounds represented by SiO x (0 ≦ x < 2) and silicon-carbon composites. Since SiO2 does not react with lithium ions and thus cannot store lithium, x is preferably within the above range, and more preferably, the silicon-based active material may be SiO.

[0147] When the silicon-based active material is used as the negative electrode active material, the above non-aqueous electrolyte can form a flexible and durable SEI layer on the surface of the negative electrode, thus preventing damage to the SEI layer due to volume expansion of the silicon-based active material and preventing an increase in the thickness of the SEI layer and electrolyte consumption due to surface exposure of the new silicon-based active material caused by volume expansion, which is highly preferable.

[0148] The average particle size (D 50 ) of the silicon-based active material may be 1 μm to 30 μm, preferably 2 μm to 15 μm, from the viewpoint of achieving structural stability during charge and discharge and reducing side reactions with the electrolyte.

[0149] The negative electrode active material may be contained in the negative electrode active material layer at 60% to 99% by weight, preferably 75% to 95% by weight.

[0150] The negative electrode active material layer may further include a binder and / or a conductive material together with the negative electrode active material.

[0151] The binder is used to improve the performance of the battery by improving the adhesion between the negative electrode active material layer and the negative electrode current collector, and may contain, for example, at least one selected from the group consisting of polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinylidene fluoride (PVDF), polyacrylonitrile, polymethyl methacrylate, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, polyacrylic acid, ethylene-propylene-diene monomer (EPDM), sulfonated EPDM, styrene-butadiene rubber (SBR), fluororubber, and substances in which the hydrogen of these substances is substituted with Li, Na, or Ca, or may contain various copolymers thereof.

[0152] The binder may be included in the negative electrode active material layer in an amount of 0.5% to 10% by weight, preferably 1% to 5% by weight.

[0153] The conductive material is not particularly limited as long as it does not cause a chemical change in the battery and is conductive. Examples include graphite such as natural graphite or artificial graphite; carbon black such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fibers and metal fibers; conductive tubes such as carbon nanotubes; fluorocarbons; metal powders such as aluminum and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and conductive materials such as polyphenylene derivatives.

[0154] The conductive material may be included in the negative electrode active material layer in an amount of 0.5% to 10% by weight, preferably 1% to 5% by weight.

[0155] The thickness of the negative electrode active material layer may be 10 μm to 100 μm, preferably 50 μm to 80 μm.

[0156] The negative electrode can be manufactured by coating at least one surface of a negative electrode current collector with a negative electrode slurry containing a negative electrode active material, a binder, a conductive material, and / or a solvent for forming the negative electrode slurry, followed by drying and rolling.

[0157] The solvent for forming the negative electrode slurry may include, for example, at least one selected from the group consisting of distilled water, NMP (N-methyl-2-pyrrolidone), ethanol, methanol, and isopropyl alcohol, preferably distilled water, in order to facilitate the dispersion of the negative electrode active material, binder, and / or conductive material. The solid content of the negative electrode slurry may be 30% to 80% by weight, specifically 40% to 70% by weight.

[0158] (3) Separator Furthermore, the separator may be a conventional porous polymer film, such as a porous polymer film made from polyolefin polymers like ethylene monopolymer, propylene monopolymer, ethylene / butene copolymer, ethylene / hexene copolymer, and ethylene / methacrylate copolymer, used alone or in a laminated configuration. Alternatively, a conventional porous nonwoven fabric, such as a nonwoven fabric made from high-melting-point glass fibers or polyethylene terephthalate fibers, may be used, but is not limited to these. In addition, a coated separator containing ceramic components or polymeric substances may be used to ensure heat resistance or mechanical strength, and may be selectively used as a single-layer or multi-layer structure.

[0159] The external shape of the lithium secondary battery of the present invention is not particularly limited, but may be cylindrical, rectangular, pouch-shaped, or coin-shaped, using a can.

[0160] The present invention will be described in more detail below with reference to specific examples. However, the following examples are merely illustrative for understanding the present invention and are not intended to limit the scope of the invention. It will be obvious to those skilled in the art that various changes and modifications are possible within the scope of the described concept and technical idea, and it goes without saying that such variations and modifications fall within the scope of the appended claims.

[0161] Examples and Comparative Examples Example 1 (Manufacturing of non-aqueous electrolytes) As the organic solvent, a mixture of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) in a volume ratio of 30:70 was used.

[0162] A non-aqueous electrolyte was prepared by adding LiPF6 as a lithium salt and a compound represented by the following chemical formula 1-A-1 as an additive to the aforementioned organic solvent.

[0163] The aforementioned LiPF6 was included in the non-aqueous electrolyte at a molar concentration of 1 M.

[0164] The compound represented by the following chemical formula 1-A-1 was included in the non-aqueous electrolyte at a concentration of 3% by weight.

[0165] [Chemical formula 1-A-1] [ka]

[0166] (Manufacturing of lithium-ion batteries) Cathode active material (Li[Ni 0.85 Co 0.05 Mn 0.07 Al 0.03A cathode mixture slurry (solid content 75.5% by weight) was prepared by adding 2O2, a conductive material (carbon nanotube), and a binder (polyvinylidene fluoride) in a weight ratio of 97.74:0.70:1.56 to the solvent N-methyl-2-pyrrolidone (NMP). The cathode mixture slurry was applied to one surface of a 12 μm thick cathode current collector (Al thin film), and the cathode was manufactured by drying and roll pressing.

[0167] A negative electrode slurry (solid content 26% by weight) was prepared by adding a negative electrode active material (natural graphite), a conductive material (carbon black), and a binder (styrene-butadiene rubber (SBR)-carboxymethylcellulose (CMC)) in a weight ratio of 96.15:1.55:2.30 to distilled water, which was used as a solvent. The negative electrode slurry was applied to one surface of a 15 μm thick negative electrode current collector (Cu thin film), and the negative electrode was manufactured by drying and roll pressing to form a negative electrode active material layer (thickness: 179.8 μm).

[0168] In a dry room, a polyethylene porous film separator was interposed between the positive electrode and negative electrode manufactured as described above, and then the non-aqueous electrolyte manufactured as described above was injected to produce a secondary battery.

[0169] Example 2 A non-aqueous electrolyte and a lithium secondary battery were manufactured in the same manner as in Example 1, except that the compound represented by chemical formula 1-A-1 was added to the non-aqueous electrolyte at a content of 0.05% by weight instead of 3% by weight.

[0170] Example 3 A non-aqueous electrolyte and a lithium secondary battery were manufactured in the same manner as in Example 1, except that the compound represented by chemical formula 1-A-1 was added to the non-aqueous electrolyte at a content of 5% by weight instead of 3% by weight.

[0171] Example 4 A non-aqueous electrolyte and a lithium secondary battery were manufactured in the same manner as in Example 1, except that instead of 3% by weight of the compound represented by chemical formula 1-A-1, a compound represented by the following chemical formula 1-B-1 was added to the non-aqueous electrolyte in a content of 3% by weight.

[0172] [Chemical formula 1-B-1] [ka]

[0173] Example 5 A nonaqueous electrolyte and a lithium secondary battery were manufactured in the same manner as in Example 4, except that the compound represented by chemical formula 1-B-1 was added to the nonaqueous electrolyte at a content of 0.05% by weight instead of 3% by weight.

[0174] Example 6 A non-aqueous electrolyte and a lithium secondary battery were manufactured in the same manner as in Example 4, except that the compound represented by chemical formula 1-B-1 was added to the non-aqueous electrolyte at a content of 5% by weight instead of 3% by weight.

[0175] Comparative Example 1 A non-aqueous electrolyte and a lithium secondary battery were manufactured in the same manner as in Example 1, except that the compound represented by chemical formula 1-A-1 was not added.

[0176] Comparative Example 2 A non-aqueous electrolyte and a lithium secondary battery were manufactured in the same manner as in Example 1, except that instead of 3% by weight of the compound represented by chemical formula 1-A-1, the compound represented by chemical formula 3 below was added to the non-aqueous electrolyte in a content of 3% by weight.

[0177] [Chemical formula 3] [ka]

[0178] Comparative Example 3 A non-aqueous electrolyte and a lithium secondary battery were produced in the same manner as in Example 1, except that the compound represented by the following Chemical Formula 4 was added to the non-aqueous electrolyte at a content of 3% by weight instead of the 3% by weight of the compound represented by Chemical Formula 1-A-1.

[0179] [Chemical Formula 4] [Chem.]

[0180] Comparative Example 4 A non-aqueous electrolyte and a lithium secondary battery were produced in the same manner as in Example 1, except that the compound represented by the following Chemical Formula 5 was added to the non-aqueous electrolyte at a content of 3% by weight instead of the 3% by weight of the compound represented by Chemical Formula 1-A-1.

[0181] [Chemical Formula 5] [Chem.]

[0182] Experimental example Experimental Example 1: Evaluation of High-Temperature Cycle Performance The lithium secondary batteries of Examples 1 to 6 and Comparative Examples 1 to 4 manufactured above were charged to 4.2 V at 0.05 C under CC / CV conditions at 45 °C using an electrochemical charger / discharger, and then discharged to 3.0 V under CC conditions at 0.5 C. One cycle was defined as such a charge-discharge process, and 200 cycles of charge-discharge were performed.

[0183] 1-1: Evaluation of Capacity Retention Rate The capacity retention rate was calculated by the following formula, and the results are shown in Table 1 below.

[0184] Capacity retention rate (%) = {(Discharge capacity after 200 cycles / Discharge capacity after 1 cycle)} × 100

[0185] 1-2: Evaluation of Resistance Increase Rate After one charge-discharge cycle, the discharge capacity after one cycle was measured using an electrochemical charger. After adjusting the SOC to 50%, a 2.5C pulse was applied for 10 seconds, and the initial resistance was calculated from the difference between the voltage before and after pulse application.

[0186] After 200 charge-discharge cycles, calculate the resistance after 200 cycles using the same method as above, calculate the resistance increase rate using the following formula, and show the results in the table below. 1 As shown.

[0187] Resistance increase rate (%) = (Resistance after 200 cycles - Initial resistance) / Initial resistance × 100

[0188] Experimental Example 2: Evaluation of High-Temperature Storage Performance The lithium secondary batteries of Examples 1-6 and Comparative Examples 1-4, manufactured as described above, were charged to 4.2V and 0.05C at 25°C under CC / CV and 0.33C conditions, and then discharged to 2.5V at 0.33C to perform initial charge and discharge. Subsequently, they were charged to 4.2V and 0.05C at 25°C under CC / CV and 0.33C conditions, and then stored at 60°C for 8 weeks.

[0189] 2-1: Evaluation of Capacity Retention Rate After 8 weeks of storage, the lithium secondary battery was charged to 4.2V and 0.05C at 25°C and 0.33C, and then discharged to 3.0V at 0.33C, and its discharge capacity was measured.

[0190] The capacity retention rate was evaluated using the following formula, and the results are shown in Table 1 below.

[0191] Capacity retention rate (%) = (Discharge capacity after 8 weeks of storage / Initial discharge capacity) × 100

[0192] 2-2: Evaluation of Resistance Increase Rate During the initial charge and discharge, the capacity was confirmed at room temperature. The SOC50 was then charged based on the discharge capacity, discharged at a current of 3C for 10 seconds, and the resistance was measured from the voltage drop difference to determine the initial resistance. After storage at 60°C for 8 weeks, the resistance was measured again using the same method to determine the final resistance, and the resistance increase rate was calculated using the following formula. The results are shown in Table 1 below.

[0193] Resistance increase rate (%) = (Final resistance - Initial resistance) / (Initial resistance) × 100

[0194] [Table 1]

[0195] Referring to Table 1 above, the lithium secondary batteries of Examples 1 to 6 using the non-aqueous electrolyte according to the present invention are compared to Comparative Example 1 to 6, which do not use the non-aqueous electrolyte. 4 Compared to the above, it can be confirmed that it exhibits significantly superior capacity retention and a low resistance increase rate during high-temperature cycle charging / discharging and high-temperature storage.

Claims

1. It contains a lithium salt, an organic solvent, and an additive. The aforementioned additive is a non-aqueous electrolyte containing a compound represented by the following chemical formula 1. [Chemical formula 1] 【Chemistry 1】 (In the above chemical formula 1, R １ This is an allyl group or a propagyl group, R ２ , R ３ , R ４ , and R ５ These are independently selected from hydrogen and alkyl groups having 1 to 5 carbon atoms. L is selected from single bonds and alkylene groups having 1 to 10 carbon atoms. X is -C(=O)-, -S(=O)-, and -S(=O) ２ (Selected from the following options.)

2. The aforementioned R １ The non-aqueous electrolyte according to claim 1, wherein the group is an allyl group.

3. The non-aqueous electrolyte according to claim 1, wherein X is selected from -C(=O)- and -S(=O)-.

4. Said R ２ , R ３ , R ４ , and R ５ are each independently an alkyl group having 1 to 5 carbon atoms, the non-aqueous electrolyte according to claim 1.

5. The non-aqueous electrolyte according to claim 1, wherein the compound represented by chemical formula 1 includes at least one selected from the group consisting of compounds represented by the following chemical formulas: 1-A, 1-B, 1-C, 2-A, 2-B, and 2-C. [Chemical formula 1-A] 【Chemistry 2】 [Chemical formula 1-B] 【Transformation 3】 [Chemical formula 1-C] 【Chemistry 4】 [Chemical formula 2-A] 【Transformation 5】 [Chemical formula 2-B] 【Transformation 6】 [Chemical formula 2-C] 【Transformation 7】 (In the above chemical formulas 1-A, 1-B, 1-C, 2-A, 2-B, and 2-C, R ２ , R ３ , R ４ , and R ５ (This is as defined in Chemical Formula 1 above.)

6. The non-aqueous electrolyte according to claim 1, wherein the compound represented by chemical formula 1 includes at least one selected from the group consisting of compounds represented by the following chemical formulas: 1-A-1, 1-A-2, 1-B-1, 1-B-2, 1-C-1, 1-C-2, 2-A-1, 2-A-2, 2-B-1, 2-B-2, 2-C-1, and 2-C-2. [Chemical formula 1-A-1] 【Transformation 8】 [Chemical formula 1-A-2] 【Chemistry 9】 [Chemical formula 1-B-1] 【Chemistry 10】 [Chemical formula 1-B-2] 【Chemistry 11】 [Chemical formula 1-C-1] 【Chemistry 12】 [Chemical formula 1-C-2] 【Chemistry 13】 [Chemical formula 2-A-1] 【Chemistry 14】 [Chemical formula 2-A-2] 【Chemistry 15】 [Chemical formula 2-B-1] 【Chemistry 16】 [Chemical formula 2-B-2] 【Chemistry 17】 [Chemical formula 2-C-1] [Chemistry 18] [Chemical formula 2-C-2] 【Chemistry 19】

7. The nonaqueous electrolyte according to any one of claims 1 to 6, wherein the compound represented by chemical formula 1 is contained in an amount of 0.01% to 10% by weight based on the weight of the nonaqueous electrolyte.

8. The lithium salts mentioned above are LiCl, LiBr, LiI, and LiBF. ４ LiClO ４ LiAlO ４ LiAlCl ４ LiPF ６ LiSbF ６ LiAsF ６ LiB １０ Cl １０ , LiBOB(LiB(C ２ O ４ ) ２ ), LiCF ３ SO ３ , LiFSi(LiN(SO ２ F) ２ ), LiCH ３ SO ３ LiCF ３ CO ２ LiCH ３ CO ２ , and LiBETI(LiN(SO ２ CF ２ CF ３ ) ２ A non-aqueous electrolyte according to any one of claims 1 to 6, comprising at least one selected from the group consisting of ).

9. The nonaqueous electrolyte according to any one of claims 1 to 6, wherein the lithium salt is contained in the nonaqueous electrolyte at a molar concentration of 0.5 M to 5.0 M.

10. The non-aqueous electrolyte according to any one of claims 1 to 6, wherein the organic solvent comprises at least one selected from the group consisting of cyclic carbonate organic solvents, linear carbonate organic solvents, linear ester organic solvents, and cyclic ester organic solvents.

11. Positive electrode and, A negative electrode opposite the positive electrode, A separator interposed between the positive electrode and the negative electrode, A lithium secondary battery comprising a non-aqueous electrolyte according to any one of claims 1 to 6.

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