Lithium battery electrolyte and lithium battery containing the same

Abstract

A lithium battery electrolyte and a lithium battery including the same are disclosed. The lithium battery electrolyte includes a lithium salt, a non-aqueous organic solvent, and an additive including a compound represented by Chemical Formula 1 disclosed herein and one or more compounds represented by Chemical Formula 2-1 and Chemical Formula 2-2 disclosed herein.

Description

[Technical field]

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

[0002] Lithium batteries, for example lithium secondary batteries, have an energy density per unit weight that is three times higher than that of existing lead-acid batteries, nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, etc., and are capable of high-speed charging.

[0003] Lithium secondary batteries operate at high drive voltages, and therefore cannot use aqueous electrolytes that are highly reactive with lithium. Organic electrolytes are generally used in lithium secondary batteries. The organic electrolyte is prepared by dissolving lithium salt in a non-aqueous organic solvent. It is preferable that the non-aqueous organic solvent is stable at high voltages, has high ionic conductivity and dielectric constant, and has low viscosity.

[0004] However, if an organic electrolyte solution is used as an electrolyte for a lithium secondary battery, side reactions between the anode / cathode and the electrolyte may cause deterioration in the life characteristics and high temperature stability of the lithium secondary battery.

[0005] To address this issue, additives have been used in electrolytes for lithium secondary batteries, but additives used to date have not provided sufficient battery life characteristics and safety over a wide range of temperatures, from room temperature to high temperature.

[0006] Therefore, there remains a demand for a lithium battery electrolyte that can provide battery life characteristics and safety over a wide temperature range from room temperature to high temperature, and a lithium battery including the same. Summary of the Invention [Problem to be solved by the invention]

[0007] One aspect of the present invention is to provide an electrolyte for a lithium battery that includes a novel electrolyte additive.

[0008] Another aspect of the present invention is to provide a lithium battery containing the electrolyte. [Means for solving the problem]

[0009] According to one aspect, A lithium salt; A non-aqueous organic solvent; There is provided an electrolyte for a lithium battery, comprising a compound represented by the following Chemical Formula 1 and an additive comprising one or more compounds selected from the compounds represented by the following Chemical Formulas 2-1 and 2-2: [ka] In the above formula 1, A1, A2, A3, and A4 are each independently a single bond, a substituted or unsubstituted C1-C5 alkylene group, a carbonyl group, or a sulfinyl group. [ka] In the above Chemical Formula 2-1, R1 is a hydrogen atom, a halogen atom, or a substituted or unsubstituted C1-C 20 Alkyl group, or -(CH2) n -X group, where n is an integer from 1 to 10 and X is a halogen atom; R2 is -(CH2) n’ -N=C=O group or -(CH2) m' It is a -N=C=S group, where n' and m' are each 0 to 10. [ka] In the above Chemical Formula 2-2, R'1 and R'3 are each independently -(CH2) n’ -N=C=O group or -(CH2) m’ -N=C=S group, where n', m' are each 0 to 10; R'2 is a substituted or unsubstituted C1-C 20It is also an alkylene group.

[0010] In the formula 1, A1, A2, A3, and A4 are each independently a single bond, a substituted or unsubstituted C1-C5 alkylene group, a carbonyl group, or a sulfinyl group; The substituted C1-C5 alkylene group is a halogen atom, a C1-C5 alkyl group, a C1-C5 alkyl group substituted with a halogen atom, a C6-C 20 Aryl groups, C6-C substituted with halogen atoms 20 Aryl groups, C6-C 20 Heteroaryl groups or C6-C substituted with halogen atoms 20 It is also a C1-C5 alkylene group substituted with one or more functional groups selected from heteroaryl groups.

[0011] In the above formula 2-1, R1 is a halogen atom, a substituted or unsubstituted C1-C 20 It may also be an alkyl group or a C1-C5 alkyl group substituted with a halogen atom.

[0012] In the formula 2-1 and the formula 2-2, R2, R'1, and R'3 are -(CH2) n’ It is also a -N=C=O group, where n' is 0-10.

[0013] The compounds represented by Formula 2-1 and Formula 2-2 include at least one of the compounds represented by Formulas 3 to 7 below: [ka]

[0014] In the electrolyte, the content of the compound represented by Formula 1 is equal to or greater than the content of at least one of the compounds represented by Formula 2-1 and Formula 2-2.

[0015] In the electrolyte, the content of the compound represented by Chemical Formula 1 is 0.01 to 5 wt % based on the total weight of the electrolyte.

[0016] In the electrolyte, the content of at least one of the compounds represented by Formula 2-1 and Formula 2-2 is 0.01 to 3 wt % based on the total weight of the electrolyte.

[0017] According to another aspect, a positive electrode including a positive electrode active material; a negative electrode including a negative electrode active material; A lithium battery is provided, comprising: an electrolyte as described above disposed between the positive electrode and the negative electrode.

[0018] The positive electrode active material includes a compound represented by the following Formula 9: [Chemical formula 9] LiNi x Co y M 1-x-y O 2-z A z In the above Chemical Formula 9, M is also one or more selected from aluminum (Al), manganese (Mn), vanadium (V), magnesium (Mg), gallium (Ga), tungsten (W), molybdenum (Mo), iron (Fe), chromium (Cr), copper (Cu), zinc (Zn), or titanium (Ti); A is also one or more selected from F, S, Cl, or Br; Also 0≦x≦1, 0≦y≦1, 0≦z≦0.3, and x+y≦1.

[0019] In Chemical Formula 9, 0.8≦x<1, and M is at least one selected from aluminum (Al), manganese (Mn), vanadium (V), magnesium (Mg), molybdenum (Mo), iron (Fe), chromium (Cr), copper (Cu), zinc (Zn), and titanium (Ti).

[0020] The negative electrode active material may include a carbon-based material, a silicon-based material, or a silicon-carbon composite.

[0021] The negative active material is a silicon-carbon composite, and the silicon content is 1 wt % or more based on the total weight of the silicon-carbon composite. Effect of the Invention

[0022] According to one aspect, an electrolyte for a lithium battery includes an additive including a compound represented by Formula 1 and one or more of the compounds represented by Formulas 2-1 and 2-2. A lithium battery including the electrolyte may have improved life characteristics and storage characteristics at room temperature and high temperature, as well as improved stability at room temperature, high temperature, and during fast charging. [Brief description of the drawings]

[0023] [Figure 1] 1 is a schematic diagram of a lithium battery according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, a lithium battery electrolyte and a lithium battery including the same will be described in detail with reference to the following examples and drawings. It will be obvious to those skilled in the art that these examples are merely illustrative examples for explaining the present invention in more detail, and the scope of the present invention is not limited by these examples.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present specification, including definitions, will control.

[0026] Although methods and materials similar or the same as those described herein may be used in the practice or testing of the present invention, suitable methods and materials are described herein. The singular term includes the plural term unless the context clearly indicates otherwise. In this specification, the terms "comprise" and "have" are intended to indicate the presence of a feature, number, step, operation, component, part, ingredient, material, or combination thereof described in the specification, and should not be understood to preclude the presence or additional possibility of one or more other features, numbers, steps, operations, components, parts, ingredients, materials, or combinations thereof.

[0027] As used herein, the term "combinations thereof" means a mixture or combination of one or more of the listed components.

[0028] As used herein, the term "and / or" is meant to include any and all combinations of one or more of the associated listed items. As used herein, the term "or" means "and / or." As used herein, the phrases "at least one," "one or more," or "one or more" preceding an element are meant to supplement the entire list of elements and not to supplement the individual elements listed.

[0029] In the drawings, thicknesses are exaggerated or reduced to clearly depict multiple layers and regions. Similar parts throughout the specification are given the same drawing reference numbers. Throughout the specification, when a part such as a layer, film, region, plate, etc. is described as being "on" or "above" another part, this includes not only when it is directly on top of the other part, but also when there is another part in between. Throughout the specification, terms such as first, second, etc. are used to describe various components, but the components should not be limited by the terms. Terms are used only to distinguish one component from another.

[0030] According to an embodiment, the electrolyte for a lithium battery includes a lithium salt; a non-aqueous organic solvent; and an additive including a compound represented by the following Formula 1 and one or more compounds represented by the following Formulas 2-1 and 2-2: [ka] In the above formula 1, A1, A2, A3, and A4 are each independently a single bond, a substituted or unsubstituted C1-C5 alkylene group, a carbonyl group, or a sulfinyl group. [ka] In the above Chemical Formula 2-1, R1 is a hydrogen atom, a halogen atom, or a substituted or unsubstituted C1-C 20 Alkyl group, or -(CH2) n -X group, where n is an integer from 1 to 10 and X is a halogen atom; R2 is -(CH2) n’ -N=C=O group or -(CH2) m’ It can also be a -N=C=S group, where n' and m' are each an integer from 0 to 10. For example, n' and m' are each an integer from 0 to 5. [ka] In the above Chemical Formula 2-2, R'1 and R'3 are each independently -(CH2) n’ -N=C=O group or -(CH2) m’ -N=C=S group, where n', m' are each 0 to 10, 1 to 5, or even 1; R'2 is a substituted or unsubstituted C1-C 20 It is also an alkylene group.

[0031] For example, in the above formula 1, A1, A2, A3, and A4 are each independently a substituted or unsubstituted C1-C5 alkylene group, a carbonyl group, or a sulfinyl group; The substituted C1-C5 alkylene group is a halogen atom, a C1-C5 alkyl group, a C1-C5 alkyl group substituted with a halogen atom, a C6-C 20 Aryl groups, C6-C substituted with halogen atoms 20 Aryl groups, C6-C 20 C6-C substituted with heteroaryl or halogen atoms 20 It is also a C1-C5 alkylene group substituted with one or more functional groups selected from heteroaryl groups.

[0032] For example, in the formula 2-1, R1 is a halogen atom, a substituted or unsubstituted C1-C 20 It may also be an alkyl group or a C1-C5 alkyl group substituted with a halogen atom.

[0033] For example, in the formula 2-1 and the formula 2-2, R2, R'1, and R'3 are -(CH2) n’ It can also be a -N=C=O group, where n' can be from 0 to 10. For example, n' can be from 0 to 5.

[0034] According to an embodiment, the electrolyte for lithium batteries includes a bicyclic sulfate-based compound represented by the formula 1, and an isocyanate-based compound or / and an isothiocyanate-based compound represented by the formula 2-1 or / and the formula 2-2 as additives. The electrolyte includes the compound represented by the formula 1 as an additive, and thus provides a lithium battery having improved storage characteristics and life characteristics at a high temperature of 60°C. The electrolyte includes the compounds represented by the formula 2-1 and the formula 2-2, and thus provides a lithium battery having improved life characteristics at room temperature (25°C) and during fast charging. The electrolyte includes the compound represented by the formula 1 and at least one of the compounds represented by the formulas 2-1 and 2-2, and thus provides a lithium battery having low DC resistance increase rate at room temperature (25°C), high temperature (60°C), and during fast charging, thereby ensuring stability.

[0035] The reason why the electrolyte for a lithium battery contains one or more of the compounds represented by Chemical Formula 1 and the compounds represented by Chemical Formula 2-1 and Chemical Formula 2-2 as additives to improve the life characteristics and stability of the lithium battery will be described in more detail below. However, this is for the purpose of aiding in the understanding of the present invention, and the scope of the present invention is not limited to the scope of the following description.

[0036] The electrolyte for a lithium battery includes the compound represented by Chemical Formula 1 as an additive. The compound includes a sulfate ester group therein, and is easily reduced and / or decomposed into radicals and / or ions during charging, forming a strong and stable SEI layer on the negative electrode, and / or is coordinated to the surface of the positive electrode to form a strong and stable protective layer on the surface of the positive electrode. In addition, unlike typical sulfate-based compounds, the compound has a plurality of rings bonded in a spiro shape and has a relatively large molecular weight, and is therefore thermally stable. As a result, the compound represented by Chemical Formula 1 can provide a lithium battery with improved storage characteristics and life characteristics at a high temperature of 60°C.

[0037] In addition, the electrolyte for lithium batteries contains one or more of the compounds represented by Formula 2-1 and Formula 2-2 as additives. The compounds contain isocyanate groups and / or isothiocyanate groups, and can form a strong and dense inactive protective film by adsorption reaction with metal or metal oxide present on the electrode surface. As a result, the compounds represented by Formula 2-1 and / or Formula 2-2 can provide a lithium battery with high output characteristics at room temperature (25°C) and improved life characteristics at high temperatures.

[0038] The electrolyte for lithium batteries includes one or more of the compounds represented by Formula 1 and Formulas 2-1 and 2-2 as additives, and does not interfere with each other, and can continuously form a stronger and more stable protective film on the electrode surface. As a result, the lithium battery including the electrolyte for lithium batteries not only has improved life characteristics and storage characteristics at room temperature and high temperature, but also has a very low DC resistance increase rate at room temperature (25° C.), high temperature (60° C.), and during fast charging, ensuring stability.

[0039] For example, the compound represented by Formula 1 may include compounds represented by the following Formulas 1-1 to 1-9: [ka] [ka]

[0040] For example, the compounds represented by Formula 2-1 and Formula 2-2 may include one or more of the compounds represented by Formulas 3 to 7 below: [ka]

[0041] In the electrolyte, the content of the compound represented by Chemical Formula 1 is equal to or greater than the content of one or more of the compounds represented by Chemical Formula 2-1 and Chemical Formula 2-2. In the electrolyte, the content of one or more of the compounds represented by Chemical Formula 2-1 and Chemical Formula 2-2 is less than the content of the compound represented by Chemical Formula 1. As a result, a lithium battery including the electrolyte can exhibit improved stability at room temperature, high temperature, and during fast charging, as well as improved life and storage characteristics at room temperature and high temperature, while maintaining the battery performance effect when the compound represented by Chemical Formula 1 is used as an additive.

[0042] In the electrolyte, the content of the compound represented by Chemical Formula 1 is 0.01 to 5 wt % based on the total weight of the electrolyte. For example, the content of the compound represented by Chemical Formula 1 is 0.01 to 4 wt %, 0.01 to 3 wt %, 0.01 to 2 wt %, or 0.01 to 1 wt % based on the total weight of the electrolyte. Within this content range, the battery performance can be further improved.

[0043] In the electrolyte, the content of one or more of the compounds represented by Formula 2-1 and Formula 2-2 is 0.01 to 3 wt % based on the total weight of the electrolyte. For example, in the electrolyte, the content of one or more of the compounds represented by Formula 2-1 and Formula 2-2 is 0.01 to 2 wt % or 0.01 to 1 wt % based on the total weight of the electrolyte. Within this content range, the battery performance can be further improved.

[0044] The lithium salt is LiPF6, LiBF4, LiSbF6, LiAsF 6、 LiClO4, LiCF3SO3, Li(CF3SO2)2N, LiC4F9SO3, LiAlO2, LiAlCl4, LiN(C x F 2x+1 SO2)(C y F 2y+1 The electrolyte may contain one or more selected from the group consisting of lithium salt, lithium difluoro bis(oxalato) phosphate (LiDFOP), lithium difluoro bis(oxalato) borate (LiDFOB), lithium bis oxalato borate (LiBOB), LiPO2F2, and LiI. The concentration of the lithium salt in the electrolyte is, but is not necessarily limited to, 0.01 to 2.0 M, and an appropriate concentration may be used as necessary. Battery performance may be further improved within the above concentration range.

[0045] The non-aqueous organic solvent may include at least one selected from ethylene carbonate (EC), ethyl methyl carbonate (EMC), methyl propyl carbonate, ethyl propyl carbonate, dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, propylene carbonate (PC), fluoroethylene carbonate (FEC), vinylene carbonate (VC), vinyl ethylene carbonate (VEC), butylene carbonate, ethyl propionate, ethyl butyrate, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, γ-valerolactone, γ-butyrolactone, or tetrahydrofuran. However, the non-aqueous organic solvent is not limited thereto, and any non-aqueous organic solvent available in the art may be used.

[0046] The electrolyte may be in a liquid or gel state.

[0047] According to another embodiment, a lithium battery may include a positive electrode including a positive electrode active material; a negative electrode including a negative electrode active material; and the above-described electrolyte disposed between the positive electrode and the negative electrode.

[0048] The lithium battery is not particularly limited in its form, and includes lithium secondary batteries such as lithium ion batteries, lithium ion polymer batteries, and lithium sulfur batteries as well as lithium primary batteries. The lithium battery includes the above-mentioned electrolyte, and can have improved life characteristics and storage characteristics at room temperature and high temperature, as well as improved stability at room temperature, high temperature, and during fast charging.

[0049] For example, the positive electrode active material includes a compound represented by the following Formula 9: [Chemical formula 9] LiNi x Co y M 1-x-y O 2-z A z In the above Chemical Formula 9, M is also one or more selected from aluminum (Al), manganese (Mn), vanadium (V), magnesium (Mg), gallium (Ga), tungsten (W), molybdenum (Mo), iron (Fe), chromium (Cr), copper (Cu), zinc (Zn), or titanium (Ti); A is also one or more selected from F, S, Cl, or Br; It is also the case that 0 ≦ x ≦ 1, 0 ≦ y < 1, 0 ≦ z ≦ 0.3, and x + y ≦ 1.

[0050] In the chemical formula 9, it is also the case that 0.8 ≦ x < 1, and M is also one or more selected from aluminum (Al), manganese (Mn), vanadium (V), magnesium (Mg), molybdenum (Mo), iron (Fe), chromium (Cr), copper (Cu), zinc (Zn), or titanium (Ti).

[0051] For example, the positive electrode active material may contain a compound represented by the following chemical formula 10 or chemical formula 11: [Chemical formula 10] LiNi x' Co y' Al z' O2 In the chemical formula 10, it is also the case that 0.6 ≦ x’ < 1, 0 < y’ < 1, 0 ≦ z’ ≦ 0.2, and x’ + y’ + z’ ≦ 1. For example, it is also the case that 0.8 ≦ x’ < 1, 0 < y’ ≦ 0.2, 0 ≦ z’ ≦ 0.2, and x’ + y’ + z’ ≦ 1. [Chemical formula 11] LiNi x" Co y" Al z" M (1-x-y-z)" O2 In the chemical formula 11, it is also the case that 0.6 ≦ x” < 1, 0 < y” < 1, 0 ≦ z” ≦ 0.2, and x” + y” + z” ≦ 1. For example, it is also the case that 0.8 ≦ x’ < 1, 0 < y’ ≦ 0.2, 0 ≦ z’ ≦ 0.2, and x” + y” + z” ≦ 1.

[0052] The negative electrode active material may contain a carbon-based material, a silicon-based material, or a silicon-carbon composite.

[0053] The carbon-based material may be crystalline carbon, amorphous carbon, or a mixture thereof. The crystalline carbon may be graphite such as amorphous, plate-like, flake-like, spherical, or fibrous natural graphite or artificial graphite, and the amorphous carbon may be soft carbon (low-temperature calcined carbon), hard carbon, mesophase pitch carbide, or calcined coke.

[0054] The silicon-based material may include silicon particles, silicon alloy particles, and / or silicon nanowires, etc. For example, the silicon-based material may also be silicon particles, and may have an average particle size of 50 nm to 150 nm.

[0055] The silicon-carbon composite may be a composite having a structure in which silicon nanoparticles are disposed on a carbon-based compound, a composite in which silicon particles are contained on the surface and inside of a carbon-based compound, or a composite in which silicon particles are coated on a carbon-based compound and contained inside the carbon-based compound. In the composite of a silicon-based compound and a carbon-based compound, the carbon-based compound may be graphite, graphene, graphene oxide, or a combination thereof.

[0056] For example, the negative active material may be a silicon-carbon composite, and the silicon content may be 1 wt% or more based on the total weight of the silicon-carbon composite. For example, the negative active material may be a silicon-carbon composite, and the silicon content may be 2 wt% or more, 3 wt% or more, 4 wt% or more, or 5 wt% or more based on the total weight of the silicon-carbon composite. For example, the negative active material may be an active material obtained by dispersing silicon nanoparticles having an average particle size of about 200 nm or less on carbon-based compound particles and then carbon coating the particles, or an active material in which silicon (Si) particles are present on and inside graphite. The silicon nanoparticles may have an average particle size of 50 nm to 150 nm. The silicon-carbon composite may have an average particle size of, for example, 1 μm to 20 μm. The initial efficiency, capacity, and life characteristics of a lithium battery including the negative active material may be further improved.

[0057] The lithium battery may be manufactured by the following method.

[0058] First, the positive electrode is prepared.

[0059] The positive electrode can be produced, for example, by the following exemplary method, but is not necessarily limited to such a method, and can be adjusted according to required conditions.

[0060] First, the positive electrode active material, conductive material, binder, and solvent are mixed to prepare a positive electrode active material composition. The prepared positive electrode active material composition is directly coated on an aluminum current collector and dried to manufacture a positive electrode plate having a positive electrode active material layer. Alternatively, the positive electrode active material composition is cast on a separate support, and then peeled off from the support to obtain a film, which is then laminated on the aluminum current collector to manufacture a positive electrode plate having a positive electrode active material layer.

[0061] Examples of the conductive material include carbon black, graphite particles, natural graphite, artificial graphite, acetylene black, ketjen black, carbon fibers, carbon nanotubes, metal powders or metal fibers or metal tubes of copper, nickel, aluminum, silver, etc., and conductive polymers such as polyphenylene derivatives. However, the conductive material is not limited to these, and any material used as a conductive material in the relevant technical field can be used.

[0062] Examples of binders that can be used include vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride, polyacrylonitrile, polymethyl methacrylate, polytetrafluoroethylene (PTFE), mixtures of the above-mentioned polymers, and styrene-butadiene rubber-based polymers. Examples of solvents that can be used include, but are not limited to, N-methylpyrrolidone (NMP), acetone, and water, and any solvent that is used in the relevant technical field can be used.

[0063] It is also possible to further add a plasticizer or pore-forming agent to the positive electrode active material composition to form pores inside the electrode plate.

[0064] The contents of the positive electrode active material, conductive material, binder, and solvent used in the positive electrode are those typically used in lithium batteries. Depending on the use and configuration of the lithium battery, one or more of the conductive material, binder, and solvent may be omitted. In addition to the above-mentioned positive electrode active materials, the positive electrode active material may further include the following positive electrode active materials.

[0065] The positive electrode active material is a lithium-containing metal oxide and can be any of those commonly used in the art. For example, one or more of composite oxides of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof can be used. Specific examples of the composite oxides include Li a A 1-b B' b D'2 (wherein 0.90≦a≦1 and 0≦b≦0.5); Li a E 1-b B' b O2-c D' c (wherein, 0.90≦a≦1, 0≦b≦0.5, and 0≦c≦0.05); LiE 2-b B' b O 4-c D' c (wherein, 0≦b≦0.5 and 0≦c≦0.05); Li a Ni 1-b-c Co b B' c D' α (wherein, 0.90≦a≦1, 0≦b≦0.5, 0≦c≦0.05, and 0<α≦2); Li a Ni 1-b-c Co b B' c O 2-α F' α (wherein, 0.90≦a≦1, 0≦b≦0.5, 0≦c≦0.05, and 0<α<2); Li a Ni 1-b-c Co b B' c O 2-α F'2 (wherein, 0.90≦a≦1, 0≦b≦0.5, 0≦c≦0.05, and 0<α<2); Li a Ni 1-b-c Mn b B' c D' α (wherein, 0.90≦a≦1, 0≦b≦0.5, 0≦c≦0.05, and 0<α≦2); Li a Ni 1-b-c Mn b B' c O 2-α F' α (wherein, 0.90≦a≦1, 0≦b≦0.5, 0≦c≦0.05, and 0<α<2); Li a Ni 1-b-c Mn b B' c O 2-α F'2 (wherein, 0.90≦a≦1, 0≦b≦0.5, 0≦c≦0.05, and 0<α<2); Li a Ni b E c G dO2 (wherein, 0.90≦a≦1, 0≦b≦0.9, 0≦c≦0.5, and 0.001≦d≦0.1); Li a Ni b Co c Mn d G e O2 (wherein, 0.90≦a≦1, 0≦b≦0.9, 0≦c≦0.5, 0≦d≦0.5, and 0.001≦e≦0.1); Li a NiG b O2 (wherein, 0.90≦a≦1, 0.001≦b≦0.1); Li a CoG b O2 (wherein, 0.90≦a≦1, 0.001≦b≦0.1); Li a MnG b O2 (wherein, 0.90≦a≦1, 0.001≦b≦0.1); Li a Mn2G b O4 (wherein 0.90≦a≦1, 0.001≦b≦0.1); QO2; QS2; LiQS2; V2O5; LiV2O5; LiI'O2; LiNiVO4; Li (3-f) J2(PO4)3(0≦f≦2);Li (3-f) Any compound represented by one of the following chemical formulas can be used: Fe2(PO4)3(0≦f≦2);LiFePO4: In the chemical formula representing the above-mentioned compound, A is Ni, Co, Mn, or a combination thereof; B' is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; D' is O, F, S, P, or a combination thereof; E is Co, Mn, or a combination thereof; F' is F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; Q is Ti, Mo, Mn, or a combination thereof; I' is Cr, V, Fe, Sc, Y, or a combination thereof; and J is V, Cr, Mn, Co, Ni, Cu, or a combination thereof.

[0066] It is also possible to use a compound in which a coating layer is added to the surface of the above-mentioned compound, and it is also possible to use a mixture of the above-mentioned compound and a compound to which a coating layer is added. The coating layer added to the surface of the above-mentioned compound includes, for example, a coating element compound such as an oxide, hydroxide, oxyhydroxide, oxycarbonate, or hydroxycarbonate of a coating element of a coating element. The compound forming such a coating layer is amorphous or crystalline. The coating element contained in the coating layer is Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, or a mixture thereof. The method of forming the coating layer is selected within a range that does not adversely affect the physical properties of the positive electrode active material. The coating method is, for example, spray coating, immersion, etc. The specific coating method is well understood by those engaged in the field, so a detailed description will be omitted.

[0067] Next, the negative electrode is prepared as follows. The negative electrode is prepared in substantially the same manner as the positive electrode, except that the negative electrode active material described above is used instead of the positive electrode active material. In addition, the conductive material, binder, and solvent in the negative electrode active material composition may be substantially the same as those in the positive electrode.

[0068] For example, a negative active material, a conductive material, a binder, and a solvent are mixed to prepare a negative active material composition, which is then directly coated onto a copper current collector to prepare a negative electrode plate, or the prepared negative active material composition is cast onto a separate support, and the negative active material film peeled off from the support is laminated onto a copper current collector to prepare a negative electrode plate.

[0069] The negative electrode active material may be any material that is used as a negative electrode active material for lithium batteries in the art other than the above-mentioned negative electrode active materials, for example, at least one material selected from lithium metal, metals that can be alloyed with lithium, transition metal oxides, non-transition metal oxides, and carbonaceous materials.

[0070] Examples of the metal capable of alloying with lithium include Si, Sn, Al, Ge, Pb, Bi, Sb, Si-Y' alloy (wherein Y' is an alkali metal, an alkaline earth metal, a Group 13 element, a Group 14 element, a transition metal, a rare earth element, or a combination thereof, and is not Si), and Sn-Y' alloy (wherein Y' is an alkali metal, an alkaline earth metal, a Group 13 element, a Group 14 element, a transition metal, a rare earth element, or a combination thereof, and is not Sn). The element Y' is, for example, 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, Ti, Ge, P, As, Sb, Bi, S, Se, Te, Po, or a combination thereof.

[0071] The transition metal oxide is, for example, lithium titanium oxide, vanadium oxide, lithium vanadium oxide, or the like.

[0072] The non-transition metal oxide is, for example, SnO2, SiO x (0 <x<2)などである。

[0073] The carbon-based material is, for example, crystalline carbon, amorphous carbon, or a mixture thereof. The crystalline carbon is, for example, graphite such as amorphous, plate-like, flake-like, spherical, or fibrous natural graphite or artificial graphite. The amorphous carbon is, for example, soft carbon (low-temperature calcined carbon), hard carbon, mesophase pitch carbide, calcined coke, etc.

[0074] The contents of the negative active material, conductive material, binder, and solvent are those typically used in lithium batteries, and one or more of the conductive material, binder, and solvent may be omitted depending on the use and configuration of the lithium battery.

[0075] Next, a separator is provided that is interposed between the positive electrode and the negative electrode.

[0076] The separator may be any separator that is generally used in lithium secondary batteries. A separator that has low resistance to ion movement of the electrolyte and has excellent electrolyte moisture-absorbing ability may be used. For example, the separator may be selected from glass fiber, polyester, Teflon, polyethylene, polypropylene, polytetrafluoroethylene (PTFE), or a combination thereof, and may be in the form of a nonwoven fabric or a woven fabric. For example, a rollable separator such as polyethylene or polypropylene may be used for a lithium ion battery, and a separator with excellent electrolyte impregnation ability may be used for a lithium ion polymer battery. For example, the separator may be manufactured by the following method.

[0077] A separator composition is prepared by mixing a polymer resin, a filler, and a solvent. The separator composition may be directly coated on the top of an electrode and dried to form a separator. Alternatively, the separator composition may be cast on a support and dried, and the separator film may be peeled off from the support and laminated on the top of an electrode to form a separator.

[0078] The polymer resin used to manufacture the separator is not particularly limited, and any material used as a binder for an electrode plate may be used, such as vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride (PVDF), polyacrylonitrile, polymethyl methacrylate, or a mixture thereof.

[0079] The electrolyte as previously described is then applied.

[0080] The electrolyte may further include an organic solid electrolyte and / or an inorganic solid electrolyte in addition to the above-mentioned electrolytes.

[0081] For example, the organic solid electrolyte may be a polyethylene derivative, a polyethylene oxide derivative, a polypropylene oxide derivative, a phosphate ester polymer, a polyester sulfide, a polyvinyl alcohol, or a polyvinylidene fluoride.

[0082] For example, the inorganic solid electrolyte may be boron oxide, lithium oxynitride, etc., but is not limited thereto, and any material used as a solid electrolyte in the art may be used. The inorganic solid electrolyte may be formed on the negative electrode by a method such as sputtering, or a separate solid electrolyte sheet may be laminated on the negative electrode.

[0083] As shown in Fig. 1, the lithium battery 1 includes a positive electrode 3, a negative electrode 2, and a composite separator 4. The positive electrode 3, the negative electrode 2, and the composite separator 4 are wound or folded and housed in a battery case 5. An electrolyte is injected into the battery case 5, and the battery case 5 is sealed with a cap assembly 6 to complete the lithium battery 1. The battery case 5 is cylindrical, but is not necessarily limited to such a shape, and may be, for example, rectangular or thin.

[0084] For example, a pouch-type lithium battery includes one or more battery structures. A separator is disposed between a positive electrode and a negative electrode to form a battery structure. The battery structures are stacked in a bi-cell structure, impregnated with an organic electrolyte, and then housed and sealed in a pouch to complete the pouch-type lithium battery. A plurality of battery structures are stacked to form a battery pack, which is used in all devices that require high capacity and high power output, such as notebook computers, smartphones, and electric vehicles.

[0085] Lithium batteries have excellent life characteristics and high rate characteristics, and are therefore used, for example, in electric vehicles (EVs), hybrid vehicles such as plug-in hybrid electric vehicles (PHEVs), and fields requiring large amounts of power storage, such as electric bicycles and power tools.

[0086] In the present specification, a and b in "carbon number a to b" refer to the carbon number of a specific functional group. That is, the functional group may contain from a to b carbon atoms. For example, "an alkyl group having 1 to 4 carbon atoms" refers to an alkyl group having 1 to 4 carbons, i.e., CH3-, CH3CH2-, CH3CH2CH2-, (CH3)2CH-, CH3CH2CH2CH2-, CH3CH2CH(CH3)-, and (CH3)3C-.

[0087] Nomenclature for a particular radical may include mono-radical or di-radical depending on the context. For example, if a substituent requires two points of attachment to the rest of the molecule, the substituent should be understood to be a diradical. For example, substituents specified for alkyl groups requiring two points of attachment include diradicals such as -CH2-, -CH2CH2-, -CH2CH(CH3)CH2-. Other radical nomenclature, such as "alkylene," clearly indicates that the radical is a diradical.

[0088] As used herein, the term "alkyl group" or "alkylene group" refers to a branched or unbranched aliphatic hydrocarbon group. In one embodiment, the alkyl group can be substituted or unsubstituted. The alkyl group includes, but is not limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl, cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl, and the like, each of which can be optionally substituted or unsubstituted. In one embodiment, the alkyl group can have 1 to 6 carbon atoms. For example, the alkyl group having 1 to 6 carbon atoms can be, but is not limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, pentyl, 3-pentyl, hexyl, and the like.

[0089] As used herein, the term "cycloalkyl group" means a fully saturated carbocyclic ring or ring system, e.g., cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl.

[0090] As used herein, the term "alkenyl group" refers to a hydrocarbon group containing at least one carbon-carbon double bond and having 2 to 20 carbon atoms, including, but not limited to, ethenyl, 1-propenyl, 2-propenyl, 2-methyl-1-propenyl, 1-butenyl, 2-butenyl, cyclopropenyl, cyclopentenyl, cyclohexenyl, cycloheptenyl, and the like. In one embodiment, the alkenyl group may be substituted or unsubstituted. In one embodiment, the alkenyl group may have 2 to 40 carbon atoms.

[0091] As used herein, the term "alkynyl group" refers to a hydrocarbon group containing at least one carbon-carbon triple bond and having 2 to 20 carbon atoms, including, but not limited to, ethynyl, 1-propynyl, 1-butynyl, 2-butynyl, and the like. In one embodiment, the alkynyl group may be substituted or unsubstituted. In one embodiment, the alkynyl group may have 2 to 40 carbon atoms.

[0092] As used herein, the term "aromatic" refers to a ring or ring system having a conjugated pi-electron system, and includes carbocyclic aromatic (e.g., phenyl) and heterocyclic aromatic (e.g., pyridine) groups. The term includes monocyclic or fused polycyclic rings (i.e., rings which share adjacent pairs of atoms), provided that the entire ring system is aromatic.

[0093] As used herein, the term "aryl group" refers to an aromatic ring or ring system whose ring backbone contains only carbon (i.e., two or more fused rings sharing two adjacent carbon atoms). If the aryl group is a ring system, each ring in the system is aromatic. For example, aryl groups include, but are not limited to, phenyl, biphenyl, naphthyl, phenanthrenyl, naphthacenyl, and the like. The aryl group may be substituted or unsubstituted.

[0094] As used herein, the term "heteroaryl group" refers to an aromatic ring system having one ring or multiple fused rings, in which one or more ring atoms are not carbon, i.e., heteroatoms. In a fused ring system, one or more heteroatoms can be present in only one ring. For example, heteroatoms include, but are not limited to, oxygen, sulfur, and nitrogen. For example, heteroaryl groups can also be, but are not limited to, furanyl, thienyl, imidazolyl, quinazolinyl, quinolinyl, isoquinolinyl, quinoxalinyl, pyridinyl, pyrrolyl, oxazolyl, indolyl, and the like.

[0095] As used herein, the terms "aralkyl group" and "alkylaryl group" refer to an aryl group linked as a substituent via an alkylene group, such as an aralkyl group having 7 to 14 carbon atoms, including, but not limited to, a benzyl group, a 2-phenylethyl group, a 3-phenylpropyl group, and a naphthylalkyl group. In one embodiment, the alkylene group is a lower alkylene group (i.e., an alkylene group having 1 to 4 carbon atoms).

[0096] As used herein, a "cycloalkenyl group" is a carbocyclic ring or ring system having one or more double bonds, but no aromatic rings, such as a cyclohexenyl group.

[0097] As used herein, a "heterogroup" is a non-aromatic ring or ring system that contains one or more heteroatoms in the ring backbone.

[0098] As used herein, "halogen" refers to a stable element belonging to group 17 of the periodic table of the elements, such as fluorine, chlorine, bromine or iodine, in particular fluorine and / or chlorine.

[0099] As used herein, a substituent is derived from an unsubstituted parent group by replacing one or more hydrogen atoms with another atom or functional group. Unless otherwise stated, when a functional group is described as being "substituted," it means that the functional group is substituted with one or more substituents selected from an alkyl group having 1 to 40 carbon atoms, an alkenyl group having 2 to 40 carbon atoms, a cycloalkyl group having 3 to 40 carbon atoms, a cycloalkenyl group having 3 to 40 carbon atoms, an alkyl group having 1 to 40 carbon atoms, and an aryl group having 7 to 40 carbon atoms. When a functional group is described as being "optionally substituted," it means that the functional group is substituted with the substituents described above.

[0100] The present invention will be described in more detail below with reference to examples and comparative examples. However, the examples are for illustrating the present invention and are not intended to limit the scope of the present invention. EXAMPLES

[0101] (Electrolyte Production) Example 1: 1% by weight of Chemical Formula 1-1 + 0.5% by weight of Chemical Formula 3 1.15M LiPF6 and vinylene carbonate were added to a mixed solvent of ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) in a volume ratio of 2:4:4. 1 wt % of a compound represented by the following Formula 1-1 and 0.5 wt % of a compound represented by the following Formula 3 were added to the mixed solvent to prepare an electrolyte. [ka]

[0102] Example 2: 1% by weight of Chemical Formula 1-1 + 0.5% by weight of Chemical Formula 6 An electrolyte was prepared in the same manner as in Example 1, except that 1 wt % of the compound represented by Formula 1-1 and 0.5 wt % of the compound represented by Formula 6 were added to the mixed solvent. [ka]

[0103] Example 3: Chemical Formula 1-1 1% by weight + Chemical Formula 3 1% by weight An electrolyte was prepared in the same manner as in Example 1, except that 1 wt % of the compound represented by Formula 1-1 and 1 wt % of the compound represented by Formula 3 were added to the mixed solvent.

[0104] Comparative Example 1 The electrolyte was prepared by adding 1.15M LiPF6 and vinylene carbonate to a mixed solvent of ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) in a volume ratio of 2:4:4.

[0105] Comparative example 2: Chemical formula 1-1 1% by weight An electrolyte was prepared in the same manner as in Example 1, except that 1 wt % of the compound represented by Formula 1-1 was added to the mixed solvent.

[0106] Comparative example 3: Chemical formula 3 0.5% by weight An electrolyte was prepared in the same manner as in Example 1, except that 0.5 wt % of the compound represented by Formula 3 was added to the mixed solvent.

[0107] Comparative example 4: Chemical formula 6 0.5% by weight An electrolyte was prepared in the same manner as in Example 1, except that 0.5 wt % of the compound represented by Formula 6 was added to the mixed solvent.

[0108] Comparative example 5: Chemical formula 1-1 1% by weight + Chemical formula 8 0.5% by weight An electrolyte was prepared in the same manner as in Example 1, except that 1 wt % of the compound represented by Formula 1-1 and 0.5 wt % of divinylsulfone represented by Formula 8 were added to the mixed solvent. [ka]

[0109] Comparative example 6: Chemical formula 1-1 1% by weight + Chemical formula 3 5% by weight An electrolyte was prepared in the same manner as in Example 1, except that 1 wt % of the compound represented by Formula 1-1 and 5 wt % of the compound represented by Formula 3 were added to the mixed solvent.

[0110] (manufacturing lithium secondary batteries) Example 4 87% by weight of graphite, 10.5% by weight of silicon-carbon compound composite, 1.5% by weight of styrene-butadiene rubber (SBR), and 1% by weight of carboxymethyl cellulose (CMC) were mixed and added to distilled water and stirred for 60 minutes using a mechanical stirrer to prepare a negative electrode active material slurry. The slurry was applied to a copper current collector having a thickness of 10 μm using a doctor blade to a thickness of about 60 μm, dried in a hot air dryer at 100°C for 0.5 hours, and then dried again in a vacuum at 120°C for 4 hours and roll pressed to prepare a negative electrode. A carbon-silicon composite containing carbon-coated silicon particles was used as the silicon-carbon compound composite.

[0111] LiNi 0.8 Co 0.1 Al 0.1 97% by weight of O2 (NCA), 0.5% by weight of artificial graphite powder as a conductive material, 0.8% by weight of carbon black (Ketjen black), 0.2% by weight of modified acrylonitrile rubber (BM-720H, Zeon Corporation), and 1.5% by weight of polyvinylidene fluoride (PVdF) were mixed and poured into N-methyl-2-pyrrolidone, and then stirred for 30 minutes using a mechanical stirrer to prepare a cathode active material slurry. The slurry was applied to a thickness of about 60 μm on a 20 μm thick aluminum current collector using a doctor blade, dried for 0.5 hours in a hot air dryer at 100°C, and then dried again for 4 hours under vacuum at 120°C, and roll pressed to prepare a cathode.

[0112] A cylindrical lithium secondary battery was manufactured using a 14 μm thick polyethylene separator with a ceramic coating on the positive electrode as a separator and the electrolyte prepared in Example 1 as an electrolyte.

[0113] Examples 5 to 6 A lithium secondary battery was manufactured in the same manner as in Example 4, except that the electrolyte prepared in Examples 2 and 3 was used instead of the electrolyte prepared in Example 1.

[0114] Comparative Examples 7 to 12 Lithium secondary batteries were manufactured in the same manner as in Example 4, except that the electrolytes prepared in Comparative Examples 1 to 6 were used instead of the electrolyte prepared in Example 1.

[0115] Evaluation example 1: Initial DC resistance (DC-IR) at room temperature (25°C) and increase in DC resistance after high temperature storage The lithium secondary batteries manufactured in Examples 4 to 6 and Comparative Examples 7 to 12 were tested under conditions of 1C / 10 sec discharge (SOC 100) at 25°C, and the initial direct current resistance (DCIR) was measured as a ΔV / ΔI (change in voltage / change in current) value for the lithium secondary batteries before they were stored at high temperature in an oven at 60°C. Then, after storing at high temperature (60°C) for 30 days, the resistance was measured and the DCIR increase rate (%) was calculated according to the following formula 1. The results are shown in Table 1 below. [Formula 1] DCIR increase rate = [DCIR(30 d.)-DCIR(0 d.)] / DCIR(0 d.) X 100% In formula 1, DCIR(30 d.) indicates the DCIR after 30 days, and DCIR(30 d.) indicates the DCIR immediately before storage.

[0116] [Table 1]

[0117] As shown in Table 1, the lithium secondary batteries manufactured according to Examples 4 to 6 had a lower DCIR increase rate after storage at high temperature (60°C) for 30 days than the lithium secondary batteries manufactured according to Comparative Examples 7 to 11 (using no additive in the electrolyte, using the compound represented by Formula 1-1 alone, the compound represented by Formula 3 alone, the compound represented by Formula 6 alone, and using the compound represented by Formula 1-1 + the compound represented by Formula 8 as an additive in the electrolyte). The lithium secondary batteries manufactured according to Examples 4 to 6 used a small amount of an isocyanate-based compound represented by Formula 3 or Formula 6 as an electrolyte additive in addition to a bicyclic sulfate-based compound. The additives contained in the electrolyte do not interfere with each other and are present in the electrolyte bulk or can form a stable coating on the electrode surface, so that it is considered that the side reaction between the electrode and the electrolyte is continuously suppressed.

[0118] Evaluation example 2: Charge / discharge characteristics at room temperature (25°C) and DC resistance increase rate at room temperature The room temperature (25° C.) charge / discharge characteristics and room temperature DC resistance increase rate of the lithium secondary batteries manufactured in Examples 4 to 6 and Comparative Examples 7 to 12 were measured and evaluated in the following manner. The results are shown in Table 2 below.

[0119] 2-1: Normal temperature (25℃) charge / discharge characteristics The lithium secondary batteries manufactured in Examples 4 to 6 and Comparative Examples 7 to 12 were charged at a constant current of 0.5 C rate at 25° C. until the voltage reached 4.2 V, and then cut off at a current of 0.2 C rate while maintaining 4.2 V in constant voltage mode. Then, discharged at a constant current of 0.5 C rate until the voltage reached 2.8 V during discharge. Such charge / discharge cycles were repeated 60 times. In all the charge / discharge cycles, a 10-minute rest period was allowed to pass after each charge / discharge cycle. The capacity retention rate at the 60th cycle is defined by the following formula 2. [Formula 2] Capacity retention rate (%) = [discharge capacity at 60th cycle / discharge capacity at first cycle] x 100

[0120] 2-2: DC resistance increase rate at room temperature (25°C) The lithium secondary batteries manufactured in Examples 4 to 6 and Comparative Examples 7 to 12 were tested under the condition of 1C / 10 seconds discharge (SOC100) at 25°C, and were subjected to 60 charge-discharge cycles at 25°C as described in "2-1: Room temperature (25°C) charge-discharge characteristics" above. After 60 charge-discharge cycles, the resistance was measured, and the DCIR increase rate (%) was calculated according to the following formula 3. [Formula 3] DCIR increase rate = DCIR (60 charge / discharge cycles) / DCIR (0 d.) x 100% In formula 3, DCIR (60 charge / discharge cycles) indicates the DCIR after 60 charge / discharge cycles at 25° C., and DCIR (0 d.) indicates the DCIR immediately before the 60 charge / discharge cycles.

[0121] [Table 2]

[0122] As shown in Table 2, the lithium secondary batteries manufactured according to Examples 4 to 6 had a higher capacity retention rate at 25° C. than the lithium secondary batteries manufactured according to Comparative Example 8 (using the compound represented by Formula 1-1 alone as an additive in the electrolyte) and Comparative Examples 11 to 12 (using the compound represented by Formula 1-1 + the compound represented by Formula 8 as an additive in the electrolyte, using the compound represented by Formula 1-1 + 5 wt % of the compound represented by Formula 3 as an additive in the electrolyte). The lithium secondary batteries manufactured according to Examples 4 to 6 had a lower DC resistance increase rate at 25° C. than the lithium secondary batteries manufactured according to Comparative Examples 7 to 9 (using no additive in the electrolyte, using the compound represented by Formula 1-1 alone, using the compound represented by Formula 3 alone as an additive) and Comparative Examples 11 to 12 (using the compound represented by Formula 1-1 + the compound represented by Formula 8 as an additive in the electrolyte, using the compound represented by Formula 1-1 + 5 wt % of the compound represented by Formula 3 as an additive in the electrolyte).

[0123] Evaluation example 3: Rapid charge / discharge characteristics and rapid charge DC resistance increase rate The rapid charge / discharge characteristics and rapid charge DC resistance increase rate of the lithium secondary batteries prepared in Examples 4 to 6 and Comparative Examples 7 to 12 were measured and evaluated in the following manner. The results are shown in Table 3 below.

[0124] 3-1: Rapid charge charge / discharge characteristics The lithium secondary battery was charged at a constant current of 2.0C to 3.0C at 25°C until the voltage reached 4.2V. Then, the battery was discharged at a constant current of 0.5C until the voltage reached 2.8V, and this cycle was repeated 60 times (60th cycle). In all of the charge / discharge cycles, a 10-minute rest period was allowed to elapse after each charge / discharge cycle. The capacity retention rate during rapid charging in the 60th cycle is defined by the following formula 4. [Formula 4] Capacity retention during fast charging (%) = [discharge capacity at 60th cycle / discharge capacity at first cycle] x 100

[0125] 3-2: DC resistance increase rate during fast charging The lithium secondary batteries manufactured in Examples 4 to 6 and Comparative Examples 7 to 12 were tested under the condition of 1C / 10 seconds discharge (SOC 100) at 25°C, and were subjected to 60 charge / discharge cycles by rapid charging at a current of 2.0C to 3.0C rate at 25°C as described in "3-1: Rapid charge / discharge characteristics" above. After rapid charging and performing 60 charge / discharge cycles, the resistance was measured, and the DCIR increase rate (%) was calculated according to the following formula 5. [Formula 5] DCIR increase rate during fast charging = DCIR (60 charge / discharge cycles) / DCIR (0 d.) x 100% In formula 3, DCIR (60 charge / discharge cycles) indicates the DCIR after 60 charge / discharge cycles at 25° C., and DCIR (0 d.) indicates the DCIR immediately before the 60 charge / discharge cycles.

[0126] [Table 3]

[0127] As shown in Table 3, the lithium secondary batteries manufactured according to Examples 4 to 6 had a higher capacity retention rate during fast charging than the lithium secondary batteries manufactured according to Comparative Example 8 (using a single additive of the compound represented by Chemical Formula 1-1 in the electrolyte) and Comparative Examples 11 to 12 (using an additive of the compound represented by Chemical Formula 1-1 + a compound represented by Chemical Formula 8 in the electrolyte, and using 5 wt % of the compound represented by Chemical Formula 1-1 + a compound represented by Chemical Formula 3 in the electrolyte). The lithium secondary batteries manufactured according to Examples 4 to 6 had a lower DC resistance increase rate during fast charging than the lithium secondary batteries manufactured according to Comparative Examples 7 to 8 (using no additive in the electrolyte, using a single additive of the compound represented by Chemical Formula 1-1 in the electrolyte) and Comparative Examples 11 to 12 (using an additive of the compound represented by Chemical Formula 1-1 + a compound represented by Chemical Formula 8 in the electrolyte, and using 5 wt % of the compound represented by Chemical Formula 1-1 + a compound represented by Chemical Formula 3 in the electrolyte). [Explanation of symbols]

[0128] 1 Lithium battery 2...Negative electrode 3...Positive electrode 4. Separator 5 Battery case 6 Assembly

Claims

1. 0.01 to 2.0 M of a lithium salt; A non-aqueous organic solvent; An additive comprising a compound represented by the following formula 1 and at least one compound selected from the compounds represented by the following formulas 2-1 and 2-2, wherein the content of the compound represented by the formula 1 is equal to or greater than the content of at least one compound selected from the compounds represented by the formulas 2-1 and 2-2, and the content of the compound represented by the formula 1 is 0.01 to 5 wt % based on the total weight of an electrolyte; Lithium battery electrolytes, including: 【Chemistry 1】 In the above formula 1, A １ , A ２ , A ３ , A ４ are each independently a single bond, a substituted or unsubstituted C １ -C ５ It is an alkylene group, a carbonyl group, or a sulfinyl group. 【Chemistry 2】 In the above Chemical Formula 2-1, R １ is a substituted or unsubstituted C １ -C ２０ Alkyl group, or -(CH ２ ) ｎ -X group, where n is an integer from 1 to 10 and X is a halogen atom; R ２ Ha-(CH ２ ) ｎ’ -N=C=O group or -(CH ２ ) ｍ' It is an --N.dbd.C.dbd.S group, where n', m' are each 0-10. 【Chemistry 3】 In the above formula 2-2, R' １ , R' ３ are each independently -(CH ２ ) ｎ’ -N=C=O group or -(CH ２ ) ｍ’ -N=C=S group, where n', m' are each 0 to 10; R' ２ is a substituted or unsubstituted C １ -C ２０ It is an alkylene group.

2. In the above Chemical Formula 1, A １ , A ２ , A ３ , A ４ are each independently substituted or unsubstituted C １ -C ５ an alkylene group, a carbonyl group, or a sulfinyl group, １ -C ５ The alkylene group is a halogen atom, １ -C ５ C substituted with alkyl or halogen atoms １ -C ５ Alkyl group, C ６ -C ２０ Aryl group, halogen-substituted C ６ -C ２０ Aryl group, C ６ -C ２０ C substituted with a heteroaryl group or a halogen atom ６ -C ２０ C substituted with one or more functional groups selected from heteroaryl groups １ -C ５ The electrolyte for a lithium battery according to claim 1 , wherein the alkylene group is an alkylene group.

3. In the above Chemical Formula 2-1, R １ is a substituted or unsubstituted C １ -C ２０ The electrolyte for a lithium battery according to claim 1 , wherein the alkyl group is an alkyl group.

4. In the formula 2-1 and the formula 2-2, R ２ , R' １ , R' ３ Ha-(CH ２ ) ｎ’ 2. The lithium battery electrolyte of claim 1, which is a -N=C=O group, where n' is 0-10.

5. 2. The electrolyte for a lithium battery according to claim 1, wherein the compounds represented by Formula 2-1 and Formula 2-2 include at least one of the compounds represented by Formulas 4 to 7: 【Chemistry 4】 。

6. 2. The electrolyte for a lithium battery according to claim 1, wherein the content of one or more of the compounds represented by Formula 2-1 and Formula 2-2 in the electrolyte is 0.01 to 3 wt % based on the total weight of the electrolyte.

7. a positive electrode including a positive electrode active material; a negative electrode including a negative electrode active material; and an electrolyte according to any one of claims 1 to 6 disposed between the positive electrode and the negative electrode.

8. 8. The lithium battery of claim 7, wherein the positive electrode active material comprises a compound represented by the following formula 9: [Chemical formula 9] L)) ｘ Co ｙ M １－ｘ－ｙ O ２－ｚ A ｚ In the above Chemical Formula 9, M is at least one selected from aluminum (Al), manganese (Mn), vanadium (V), magnesium (Mg), gallium (Ga), tungsten (W), molybdenum (Mo), iron (Fe), chromium (Cr), copper (Cu), zinc (Zn), and titanium (Ti); A is one or more selected from F, S, Cl, or Br; 0≦x≦1, 0≦y≦1, 0≦z≦0.3, and x+y≦1.

9. 9. The lithium battery of claim 8, wherein, in Chemical Formula 9, 0.8≦x<1, and M is at least one selected from the group consisting of aluminum (Al), manganese (Mn), vanadium (V), magnesium (Mg), molybdenum (Mo), iron (Fe), chromium (Cr), copper (Cu), zinc (Zn), and titanium (Ti).

10. 8. The lithium battery of claim 7, wherein the negative electrode active material comprises a carbon-based material, a silicon-based material, or a silicon-carbon-based composite.

11. 8. The lithium battery of claim 7, wherein the negative active material is a silicon-carbon composite, and the silicon content is 1 wt % or more based on the total weight of the silicon-carbon composite.

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