Positive electrode slurry for lithium secondary battery, positive electrode for lithium secondary battery, and lithium secondary battery comprising same

Abstract

Provided are a positive electrode slurry for a lithium secondary battery, a positive electrode for a lithium secondary battery, and a lithium secondary battery, wherein the positive electrode slurry comprises a positive electrode active material, a binder, and a positive electrode additive, and the positive electrode additive comprises a compound of chemical formula 1.

Description

Anode slurry for a lithium secondary battery, anode for a lithium secondary battery, and a lithium secondary battery including the same

[0001] The invention relates to a positive electrode slurry for a lithium secondary battery, a positive electrode for a lithium secondary battery, and a lithium secondary battery containing the same.

[0002] Recently, accompanied by the rapid proliferation of battery-powered electronic devices such as mobile phones, laptop computers, and electric vehicles, the demand for high-energy-density, high-capacity rechargeable batteries is rapidly increasing. Accordingly, research and development to improve the performance of lithium-ion batteries is actively underway.

[0003] A lithium secondary battery is a battery comprising a positive electrode and a negative electrode containing an active material capable of lithium ion intercalation and deintercalation, and an electrolyte, which produces electrical energy through oxidation and reduction reactions when lithium ions are intercalated or deintercalated from the positive and negative electrodes.

[0004] For lithium secondary batteries, it may be desirable to have high energy density, longevity, and high-temperature storage performance.

[0005] One embodiment provides a positive electrode slurry for a lithium secondary battery that can realize a positive electrode for a lithium secondary battery that provides a high capacity retention rate, a low resistance increase rate and a low gas generation rate after storage at high temperature, and has excellent lifespan at high temperature.

[0006] One embodiment provides a positive electrode slurry for a lithium secondary battery.

[0007] 1. A positive electrode slurry for a lithium secondary battery comprises a positive electrode active material, a binder, and a positive electrode additive, and the positive electrode additive comprises a compound of the following chemical formula 1:

[0008] [Chemical Formula 1]

[0009]

[0010] In the above chemical formula 1,

[0011] L 1 , L 2 , L 3 , R 1 and R 2 Each is as defined in the description of the invention below.

[0012] In 2.1, the above chemical formula 1 is a positive electrode slurry for a lithium secondary battery represented by chemical formula 1-1:

[0013] [Chemical Formula 1-1]

[0014]

[0015] In the above chemical formula 1-1,

[0016] L 4 is a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C1 to C20 alkoxylene group, a substituted or unsubstituted C2 to C20 alkenylene group, a substituted or unsubstituted C2 to C20 alkynylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, or a substituted or unsubstituted C2 to C20 heteroarylene group, and

[0017] L 5 and L 6 Each is an independently substituted or unsubstituted C1 to C20 alkylene group,

[0018] R 3 , R 4 , R 5 and R 6 Each is independently hydrogen, a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C1 to C20 alkoxy group, a substituted or unsubstituted C2 to C20 alkenyl group, a substituted or unsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C6 to C20 aryl group, or a substituted or unsubstituted C2 to C20 heteroaryl group.

[0019] 3.1 to 2, wherein the additive of Formula 1 comprises one or more of the following Formulas 1-4 to 1-8, a positive electrode slurry for a lithium secondary battery:

[0020] [Chemical Formula 1-4]

[0021]

[0022] [Chemical Formula 1-5]

[0023]

[0024] [Chemical Formula 1-6]

[0025]

[0026] [Chemical Formula 1-7]

[0027]

[0028] [Chemical Formula 1-8]

[0029]

[0030] 4. A positive electrode slurry for a lithium secondary battery, wherein, in 1 to 3, the compound of Formula 1 is included in an amount of 0.01 to 10 parts by weight per 100 parts by weight of the positive electrode active material.

[0031] 5. A positive electrode slurry for a lithium secondary battery, wherein the positive electrode active material comprises a lithium transition metal composite oxide in accordance with 1 to 4.

[0032] 6. A positive electrode slurry for a lithium secondary battery, wherein the lithium nickel-based oxide in 1 to 5 is represented by the following chemical formula 2:

[0033] [Chemical Formula 2]

[0034] Li a1 Ni x1 M 1 y1 M 2 z1 O 2-b1 X b1

[0035] In the above chemical formula 2,

[0036] 0.9≤a1≤1.8, 0.3≤x1≤1, 0≤y1≤0.7, 0≤z1≤0.7, 0.9≤x1+y1+z1≤1.1, and 0≤b1≤0.1, and M 1 and M 2 Each is independently one or more elements selected from the group consisting of Al, B, Ba, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W, and Zr, and X is one or more elements selected from the group consisting of F, P, and S.

[0037] 7. A positive electrode slurry for a lithium secondary battery, wherein in Formula 2 of 1 to 6, 0 0.8≤x1≤1, 0≤y1≤0.2, and 0≤z1≤0.2.

[0038] 8. In 1 to 7, the slurry further comprises a conductive material, and

[0039] A positive electrode slurry for a lithium secondary battery, comprising, based on a total of 100 parts by weight, 90 to 99 parts by weight of the positive electrode active material, 0.5 to 5 parts by weight of the conductive material, and 0.5 to 5 parts by weight of the binder.

[0040] 9. A positive electrode for a lithium secondary battery comprising a dried product of a positive electrode slurry for a lithium secondary battery according to any one of 1 to 8.

[0041] 10. A lithium secondary battery comprising a positive electrode; and a negative electrode, wherein the positive electrode comprises a dried product of the positive electrode slurry of any one of claims 1 to 8.

[0042] 11. A lithium secondary battery according to 10, wherein the cathode comprises a Si composite and graphite as a cathode active material.

[0043] 12. A lithium secondary battery according to 10 to 11, wherein the Si composite:graphite is included in a weight ratio of 3:97 to 20:80.

[0044] 13. The lithium secondary battery according to 10 to 12 further comprises an electrolyte, and

[0045] A lithium secondary battery, wherein the electrolyte comprises a non-aqueous organic solvent and a lithium salt, and the non-aqueous organic solvent is a mixture comprising ethylene carbonate (EC): ethylmethyl carbonate (EMC): dimethyl carbonate (DMC) in a volume ratio of 10 to 30: 10 to 40: 40 to 80.

[0046] 14. The lithium secondary battery in 10 to 13 is a prismatic lithium secondary battery.

[0047] 15. A lithium secondary battery according to 10 to 14, wherein the operating driving voltage of the lithium secondary battery is 4.25V or higher.

[0048] A positive electrode slurry for a lithium secondary battery according to one embodiment can have the effect of improving the lifespan characteristics and stability of the battery by improving the high-temperature lifespan and high-temperature storage performance in the battery.

[0049] FIG. 1 is a conceptual diagram briefly illustrating a lithium secondary battery according to one embodiment of the present invention.

[0050] FIGS. 2 to 5 are cross-sectional views schematically illustrating a lithium secondary battery according to one embodiment.

[0051] In order to fully understand the structure and effects of the present invention, preferred embodiments of the present invention are described with reference to the attached drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various forms and various modifications can be made. The description of these embodiments is provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention.

[0052] In this specification, when a component is described as being on another component, it means that it may be formed directly on the other component or that a third component may be interposed between them. Additionally, in the drawings, the thicknesses of the components are exaggerated for the effective description of the technical content. Throughout the specification, parts indicated by the same reference numeral represent the same components.

[0053] Unless otherwise specified in this specification, the singular form may also include the plural. Additionally, unless otherwise specified, "A or B" may mean "comprising A, comprising B, or comprising A and B." As used herein, "comprises" and / or "comprising" do not exclude the presence or addition of one or more other components to the mentioned components.

[0054] In this specification, "combination of these" may mean a mixture of components, a laminate, a composite, a copolymer, an alloy, a blend, and a reaction product, etc.

[0055] In this specification, "substitution" means that, unless otherwise defined, at least one hydrogen of a substituent or compound is substituted with a deuterium, a halogen group, a hydroxyl group, an amino group, a C1 to C30 amine group, a nitro group, a C1 to C40 silyl group, a C1 to C30 alkyl group, a C1 to C10 alkylsilyl group, a C6 to C30 arylsilyl group, a C3 to C30 cycloalkyl group, a C3 to C30 heterocycloalkyl group, a C6 to C30 aryl group, a C2 to C30 heteroaryl group, a C1 to C20 alkoxy group, a C1 to C10 fluoroalkyl group, a cyano group, or a combination thereof.

[0056] Specifically, "substitution" may mean that at least one hydrogen in the substituent or compound is substituted with deuterium, a halogen group, a C1 to C30 alkyl group, a C1 to C10 alkylsilyl group, a C6 to C30 arylsilyl group, a C3 to C30 cycloalkyl group, a C3 to C30 heterocycloalkyl group, a C6 to C30 aryl group, a C2 to C30 heteroaryl group, a C1 to C10 fluoroalkyl group, or a cyano group. For example, "substitution" may mean that at least one hydrogen in the substituent or compound is substituted with deuterium, a halogen group, a C1 to C20 alkyl group, a C6 to C30 aryl group, a C1 to C10 fluoroalkyl group, or a cyano group. Alternatively, "substitution" may mean that at least one hydrogen in the substituent or compound is substituted with a deuterium, a halogen group, a C1 to C5 alkyl group, a C6 to C18 aryl group, a C1 to C5 fluoroalkyl group, or a cyano group. For example, "substitution" may mean that at least one hydrogen in the substituent or compound is substituted with a deuterium, a cyano group, a halogen group, a methyl group, an ethyl group, a propyl group, a butyl group, a phenyl group, a biphenyl group, a terphenyl group, a trifluoromethyl group, or a naphthyl group.

[0057] Unless otherwise defined in this specification, "*" means a part connected to the same or different atoms or chemical formulas.

[0058] Unless otherwise specifically mentioned in the chemical formulas described in this specification, hydrogen may be considered to be bonded in the structure of the chemical formula.

[0059] FIG. 1 is a conceptual diagram briefly illustrating a lithium secondary battery according to embodiments of the present invention. Referring to FIG. 1, the lithium secondary battery may include a positive electrode (10), a negative electrode (20), a separator (30), and an electrolyte (ELL).

[0060] The positive electrode (10) and the negative electrode (20) may be spaced apart from each other with a separator (30) in between. The separator (30) may be placed between the positive electrode (10) and the negative electrode (20). The positive electrode (10), the negative electrode (20), and the separator (30) may come into contact with an electrolyte (ELL). The positive electrode (10), the negative electrode (20), and the separator (30) may be impregnated within the electrolyte (ELL).

[0061] The electrolyte (ELL) may be a medium for transferring lithium ions between the positive electrode (10) and the negative electrode (20). Within the electrolyte (ELL), the lithium ions may pass through a separator (30) and move toward the positive electrode (10) or the negative electrode (20).

[0062] positive electrode (10)

[0063] A positive electrode (10) for a lithium secondary battery may include a current collector (COL1) and a positive electrode active material layer (AML1) formed on the current collector (COL1). The positive electrode active material layer (AML1) may include a positive electrode active material and may further include a binder and / or a conductive material.

[0064] For example, the anode (10) may further include an additive that can serve as a sacrificial anode.

[0065] The content of the positive active material in the positive active material layer (AML1) may be 90% to 99.5% by weight with respect to 100% by weight of the positive active material layer (AML1). The content of the binder and the conductive material may each be 0.5% to 5% by weight with respect to 100% by weight of the positive active material layer (AML1).

[0066] The above binder serves to adhere the positive active material particles well to each other and also to adhere the positive active material well to the current collector (COL1). Representative examples of binders include, but are not limited to, polyvinyl alcohol, carboxymethylcellulose, hydroxypropylcellulose, diacetylcellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, epoxy resin, (meth)acrylic resin, polyester resin, nylon, etc.

[0067] The above conductive material is used to impart conductivity to the electrode, and any electronically conductive material that does not cause chemical changes can be used in the battery being constructed. Examples of conductive materials include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, carbon nanotube; metal-based materials in the form of metal powder or metal fibers containing copper, nickel, aluminum, silver, etc.; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0068] Al can be used as the current collector (COL1), but is not limited thereto.

[0069] positive electrode active material

[0070] As the positive active material in the positive active material layer (AML1), a compound capable of reversible intercalation and deintercalation of lithium (a lithated intercalation compound) may be used. Specifically, one or more composite oxides of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof may be used.

[0071] The above composite oxide may be a lithium transition metal composite oxide, and specific examples include a lithium nickel-based oxide, a lithium cobalt-based oxide, a lithium manganese-based oxide, a lithium iron phosphate-based compound, a cobalt-free lithium nickel-manganese-based oxide, or a combination thereof.

[0072] As an example, a compound represented by any one of the following chemical formulas may be used. Li a A 1-b X b O 2-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Mn 2-b X b O 4-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Ni 1-b-c Co b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b-c Mn b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni b Co c L 1 d G e O2(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0≤e≤0.1); Li a NiG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a CoG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-b G b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Lia Mn2G b O4(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-g G g PO4(0.90≤a≤1.8, 0≤g≤0.5); Li (3-f) Fe2(PO4)3(0≤f≤2); Li a FePO4(0.90≤a≤1.8).

[0073] In the above chemical formula, A is Ni, Co, Mn, or a combination thereof; X 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; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; L 1 is Mn, Al, or a combination thereof.

[0074] For example, the above-mentioned positive electrode active material may be a high-nickel positive electrode active material in which the nickel content relative to 100 mol% of the metal excluding lithium in the lithium transition metal composite oxide is 80 mol% or more, 85 mol% or more, 90 mol% or more, 91 mol% or more, or 94 mol% or more and 99 mol% or less. The high-nickel positive electrode active material can achieve high capacity and can be applied to high-capacity, high-density lithium secondary batteries.

[0075] Negative electrode (20)

[0076] A negative electrode (20) for a lithium secondary battery comprises a current collector (COL2) and a negative electrode active material layer (AML2) located on the current collector (COL2). The negative electrode active material layer (AML2) comprises a negative electrode active material and may further comprise a binder and / or a conductive material.

[0077] For example, the negative electrode active material layer (AML2) may contain 90% to 99% by weight of negative electrode active material, 0.5% to 5% by weight of binder, and 0% to 5% by weight of conductive material.

[0078] The above binder serves to effectively bond the negative electrode active material particles to each other and also to effectively bond the negative electrode active material to the current collector (COL2). As the binder, a non-aqueous binder, an aqueous binder, a dry binder, or a combination thereof may be used.

[0079] Examples of the above-mentioned non-aqueous binders include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamide imide, polyimide, or combinations thereof.

[0080] The above-mentioned water-based binder may be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluororubber, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylenepropylenediene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0081] When a water-based binder is used as the above-mentioned cathode binder, a cellulose-based compound capable of imparting viscosity may be further included. As this cellulose-based compound, one or more types such as carboxymethyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, or alkali metal salts thereof may be mixed and used. Na, K, or Li may be used as the alkali metal.

[0082] The above dry binder is a polymer material capable of fiberization, and may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or a combination thereof.

[0083] The above conductive material is used to impart conductivity to the electrode, and any electronically conductive material that does not cause chemical changes can be used in the battery being constructed. Specific examples include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjenblack, carbon fiber, carbon nanofiber, carbon nanotube; metal-based materials in the form of metal powder or metal fibers including copper, nickel, aluminum, silver, etc.; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0084] As the current collector (COL2), copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and combinations thereof may be used.

[0085] cathode active material

[0086] The negative electrode active material in the negative electrode active material layer (AML2) comprises a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material capable of doping and dedoping lithium, or a transition metal oxide.

[0087] A material capable of reversibly intercalating / deintercalating the above lithium ions may be a carbon-based negative electrode active material, such as crystalline carbon, amorphous carbon, or a combination thereof. Examples of the crystalline carbon include graphite such as amorphous, plate-like, flake-like, spherical, or fibrous natural graphite or artificial graphite, and examples of the amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, calcined coke, etc.

[0088] As the above lithium metal alloy, an alloy of lithium and a metal selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn may be used.

[0089] As a material capable of doping and undoping the above lithium, a Si-based negative electrode active material or a Sn-based negative electrode active material may be used. The Si-based negative electrode active material may be silicon, a silicon-carbon composite, SiOx (0 < x < 2), a Si-Q alloy (wherein Q is selected from alkali metals, alkaline earth metals, group 13 elements, group 14 elements (excluding Si), group 15 elements, group 16 elements, transition metals, rare earth elements, and combinations thereof), or a combination thereof. The Sn-based negative electrode active material may be Sn, SnO2, a Sn-based alloy, or a combination thereof.

[0090] The silicon-carbon composite may be a composite of silicon and amorphous carbon. According to one embodiment, the silicon-carbon composite may be in the form of silicon particles and amorphous carbon coated on the surface of the silicon particles. For example, it may include a secondary particle (core) assembled from silicon primary particles and an amorphous carbon coating layer (shell) located on the surface of the secondary particle. The amorphous carbon may also be located between the silicon primary particles, so that, for example, the silicon primary particles may be coated with amorphous carbon. The secondary particles may be dispersed in an amorphous carbon matrix.

[0091] The silicon-carbon composite may further include crystalline carbon. For example, the silicon-carbon composite may include a core comprising crystalline carbon and silicon particles and an amorphous carbon coating layer located on the surface of the core.

[0092] The above Si-based or Sn-based negative electrode active material can be used in combination with a carbon-based negative electrode active material.

[0093] Separator (30)

[0094] Depending on the type of lithium secondary battery, a separator (30) may be present between the positive electrode (10) and the negative electrode (20). As such a separator (30), polyethylene, polypropylene, polyvinylidene fluoride, or a multilayer film of two or more layers thereof may be used, and of course, a mixed multilayer film such as a polyethylene / polypropylene two-layer separator, a polyethylene / polypropylene / polyethylene three-layer separator, or a polypropylene / polyethylene / polypropylene three-layer separator may be used.

[0095] The separator (30) may include a porous substrate and a coating layer comprising an organic material, an inorganic material, or a combination thereof located on one or both sides of the porous substrate.

[0096] The porous substrate may be a polymer membrane formed from any one of the following: polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate and polybutylene terephthalate; polyacetal; polyamide; polyimide; polycarbonate; polyetherketone; polyaryletherketone; polyetherimide; polyamideimide; polybenzimidazole; polyethersulfone; polyphenylene oxide; cyclic olefin copolymer; polyphenylene sulfide; polyethylene naphthalate; glass fiber; Teflon; and polytetrafluoroethylene, or a copolymer or mixture of two or more of these.

[0097] The above organic material may include a polyvinylidene fluoride-based polymer or a (meth)acrylic-based polymer.

[0098] The above inorganic materials are Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, It may include, but is not limited to, inorganic particles selected from SrTiO3, BaTiO3, Mg(OH)2, boehmite, and combinations thereof.

[0099] The above organic and inorganic materials may exist mixed in a single coating layer, or may exist in a stacked form with a coating layer containing organic materials and a coating layer containing inorganic materials.

[0100] Electrolyte (ELL)

[0101] The electrolyte (ELL) for lithium secondary batteries contains a non-aqueous organic solvent and a lithium salt.

[0102] The above-mentioned non-aqueous organic solvent serves as a medium through which ions involved in the electrochemical reaction of the battery can move.

[0103] The above-mentioned non-aqueous organic solvent may be a carbonate-based, ester-based, ether-based, ketone-based, or alcohol-based solvent, an aprotic solvent, or a combination thereof.

[0104] The above carbonate-based solvents may include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), ethylmethyl carbonate (EMC), ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), etc.

[0105] Ester-based solvents such as methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methylpropionate, ethylpropionate, decanolide, mevalonolactone, valerolactone, and caprolactone may be used.

[0106] As ether-based solvents, dibutyl ether, tetraglame, diglame, dimethoxyethane, 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, tetrahydrofuran, etc. may be used. Additionally, as ketone-based solvents, cyclohexanone, etc. may be used. As alcohol-based solvents, ethyl alcohol, isopropyl alcohol, etc. may be used, and as aprotic solvents, nitriles such as R-CN (where R is a straight-chain, branched, or cyclic hydrocarbon group having 2 to 20 carbon atoms and may include a double bond, an aromatic ring, or an ether group); amides such as dimethylformamide; dioxolanes such as 1,3-dioxolane, 1,4-dioxolane; sulfolanes, etc. may be used.

[0107] The above-mentioned non-aqueous organic solvent can be used alone or in a mixture of two or more types.

[0108] In addition, when using a carbonate-based solvent, a mixture of cyclic carbonates and chain carbonates can be used, and the cyclic carbonates and chain carbonates can be mixed in a volume ratio of 1:1 to 1:9.

[0109] The above lithium salt is a substance that dissolves in an organic solvent and acts as a source of lithium ions within the battery, enabling the basic operation of a lithium secondary battery and facilitating the movement of lithium ions between the anode and cathode. Representative examples of lithium salts include LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiAlO2, LiAlCl4, LiPO2F2, LiCl, LiI, LiN(SO3C2F5)2, Li(FSO2)2N (lithium bis(fluorosulfonyl)imide (LiFSI), LiC4F9SO3, LiN(C x F 2x+1 SO2)(C y F 2y+1It may include one or more selected from SO2)(x and y are integers from 1 to 20), lithium trifluoromethane sulfonate, lithium tetrafluoroethane sulfonate, lithium difluorobis(oxalate)borate (LiDFOB), lithium difluorobis(oxalate)phosphate (LiDFOP), and lithium bis(oxalate)borate (LiBOB).

[0110] lithium secondary battery

[0111] Lithium secondary batteries can be classified into cylindrical, prismatic, pouch, coin, etc., depending on their shape. FIGS. 2 to 5 are schematic diagrams illustrating lithium secondary batteries according to one embodiment, where FIG. 2 is a cylindrical battery, FIG. 3 is a prismatic battery, and FIGS. 4 and 5 are pouch-type batteries. Referring to FIGS. 2 to 4, the lithium secondary battery (100) may include an electrode assembly (40) having a separator (30) interposed between a positive electrode (10) and a negative electrode (20), and a case (50) in which the electrode assembly (40) is housed. The positive electrode (10), the negative electrode (20), and the separator (30) may be impregnated with an electrolyte (not shown). The lithium secondary battery (100) may include a sealing member (60) that seals the case (50) as in FIG. 2. In addition, in FIG. 3, the lithium secondary battery (100) may include a positive lead tab (11) and a positive terminal (12), a negative lead tab (21) and a negative terminal (22). As shown in FIG. 4 and FIG. 5, the lithium secondary battery (100) may include electrode tabs (70), namely a positive tab (71) and a negative tab (72), which serve as electrical passages for inducing current formed in the electrode assembly (40) to the outside.

[0112] Hereinafter, a positive electrode slurry for a lithium secondary battery according to one embodiment of the present invention will be described in more detail.

[0113] The above-mentioned positive electrode slurry for a lithium secondary battery comprises a positive electrode active material, a binder, and a positive electrode additive, and the positive electrode additive comprises a compound of Chemical Formula 1 below:

[0114] [Chemical Formula 1]

[0115]

[0116] In the above chemical formula 1

[0117] L 1 ... is a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C1 to C20 alkoxylene group, a substituted or unsubstituted C2 to C20 alkenylene group, a substituted or unsubstituted C2 to C20 alkynylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, or a substituted or unsubstituted C2 to C20 heteroarylene group, and

[0118] L 2 and L 3 Each is independently a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C1 to C20 alkoxylene group, a substituted or unsubstituted C2 to C20 alkenylene group, a substituted or unsubstituted C2 to C20 alkynylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, or a substituted or unsubstituted C2 to C20 heteroarylene group, and

[0119] R 1 and R 2 Each is an independently substituted or unsubstituted triazole group.

[0120] In one embodiment, L in Formula 1 above 1 , L 2 and L 3Each may be an independently substituted or unsubstituted C1 to C20 alkylene group, for example, a substituted or unsubstituted C1 to C10 alkylene group, or a substituted or unsubstituted C1 to C5 alkylene group, for example, methylene, ethylene, straight-chain or branched-chain propylene, straight-chain or branched-chain butylene, or straight-chain or branched-chain pentylene group. In this case, when the additive of Formula 1 is applied to a slurry containing a positive electrode active material with a high nickel content, it may have an excellent effect in improving the lifespan of the battery at high voltage and high temperature.

[0121] When the additive of Chemical Formula 1 above is applied to a slurry containing a positive electrode active material with a high nickel content, it may have an excellent effect in improving the lifespan of the battery at high voltage and high temperature. The additive of Chemical Formula 1 above has the L described above between the SO2 group and the triazole group. 2 and L 3 This exists. This is because SO2 attracts electrons, so L 2 and L 3 The hydrogen portion acquires a relative positive charge, and this positive charge is transferred to the anions of the lithium salt in the electrolyte, particularly PF6 - It is thought that this is because it can further stabilize the anions, but the present invention is not limited thereto.

[0122] In one embodiment, R in Chemical Formula 1 1 and R 2 Each can be independently a substituted or unsubstituted 1,2,3-triazole or a substituted or unsubstituted 1,2,4-triazole.

[0123] The additive of Formula 1 according to another embodiment of the present invention may be one or more of the additives of Formula 1-1 and Formula 1-2 below:

[0124] [Chemical Formula 1-1]

[0125]

[0126] [Chemical Formula 1-2]

[0127]

[0128] In the above chemical formulas 1-1 and 1-2,

[0129] L 4 is a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C1 to C20 alkoxylene group, a substituted or unsubstituted C2 to C20 alkenylene group, a substituted or unsubstituted C2 to C20 alkynylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, or a substituted or unsubstituted C2 to C20 heteroarylene group, and

[0130] L 5 and L 6 Each is an independently substituted or unsubstituted C1 to C20 alkylene group,

[0131] R 3 , R 4 , R 5 and R 6 Each is independently hydrogen, a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C1 to C20 alkoxy group, a substituted or unsubstituted C2 to C20 alkenyl group, a substituted or unsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C6 to C20 aryl group, or a substituted or unsubstituted C2 to C20 heteroaryl group.

[0132] Preferably, the additive of Formula 1 can be the additive of Formula 1-1.

[0133] In one specific example, L 4The alkylene group may be a substituted or unsubstituted C1 to C20 alkylene group, for example, a substituted or unsubstituted C1 to C10 alkylene group, or a substituted or unsubstituted C1 to C5 alkylene group, for example, methylene, ethylene, straight-chain or branched-chain propylene, straight-chain or branched-chain butylene, or straight-chain or branched-chain pentylene group. In such cases, when the additive of Formulas 1-1 and 1-2 is applied to a slurry containing a positive electrode active material with a high nickel content, it may have an excellent effect in improving the lifespan of the battery at high voltage and high temperature.

[0134] In one specific example, L 5 and L 6 The group may be, for example, a substituted or unsubstituted C1 to C10 alkylene group, or a substituted or unsubstituted C1 to C5 alkylene group, for example, methylene, ethylene, straight-chain or branched-chain propylene, straight-chain or branched-chain butylene, or straight-chain or branched-chain pentylene group. In such cases, when the additive of Formulas 1-1 and 1-2 is applied to a slurry containing a positive electrode active material with a high nickel content, it may have an excellent effect in improving the lifespan of the battery at high voltage and high temperature.

[0135] In one embodiment, the above R 3 , R 4 , R 5 and R 6 Each may independently be a hydrogen or a substituted or unsubstituted C1 to C20 alkyl group, or a hydrogen or a substituted or unsubstituted C1 to C5 alkyl group.

[0136] In one embodiment, the additive of Formula 1 may include one or more of the following Formulas 1-4 to 1-8.

[0137] [Chemical Formula 1-4]

[0138]

[0139] [Chemical Formula 1-5]

[0140]

[0141] [Chemical Formula 1-6]

[0142]

[0143] [Chemical Formula 1-7]

[0144]

[0145] [Chemical Formula 1-8]

[0146]

[0147] Each of the additives of Formula 1 above can be synthesized through conventional synthesis methods known to those skilled in the art. For example, the additives can be prepared using 4H-1,2,4-triazole or 1H-1,2,3-triazole and a compound providing an SO2 functional group.

[0148] For example, at least a portion of the compound of Formula 1 above can be coated on the surface of the positive active material.

[0149] The compound of Formula 1 may be included in an amount of 0.01 to 10 parts by weight per 100 parts by weight of the positive electrode active material. The content of the compound of Formula 1 may refer to the content of the compound of Formula 1 in the positive electrode slurry relative to the total weight of the positive electrode active material in the positive electrode slurry, which is 100 parts by weight. Within the above content range, a positive electrode that provides a high capacity retention rate and a low resistance increase rate at high temperatures may be provided. For example, the compound of Formula 1 may be included in an amount of 0.01 to 5 parts by weight, 0.05 to 5 parts by weight, 0.1 to 5 parts by weight, or 2 to 5 parts by weight per 100 parts by weight of the positive electrode active material.

[0150] The above-described anode slurry may include the above-described lithium transition metal composite oxide as an anode active material. That is, the above-described anode slurry may include a lithium nickel-based oxide, a lithium cobalt-based oxide, a lithium manganese-based oxide, a lithium iron phosphate-based oxide, a cobalt-free nickel manganese-based oxide, or a combination thereof.

[0151] In one embodiment, the anode slurry may include a lithium nickel-based oxide as an anode active material. Specifically, the lithium nickel-based oxide may be represented by the following chemical formula 2:

[0152] [Chemical Formula 2]

[0153] Li a1 Ni x1 M 1 y1 M 2 z1 O 2-b1 X b1

[0154] In the above chemical formula 2,

[0155] 0.9≤a1≤1.8, 0.3≤x1≤1, 0≤y1≤0.7, 0≤z1≤0.7, 0.9≤x1+y1+z1≤1.1, and 0≤b1≤0.1, and M 1 and M 2 Each is independently one or more elements selected from the group consisting of Al, B, Ba, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W, and Zr, and X is one or more elements selected from the group consisting of F, P, and S.

[0156] In the above chemical formula 2, 0.6≤x1≤1, 0≤y1≤0.4, and 0≤z1≤0.4, or 0.8≤x1≤1, 0≤y1≤0.2, and 0≤z1≤0.2.

[0157] For example, the above-mentioned positive electrode active material may be a high-nickel positive electrode active material in which the nickel content relative to 100 mol% of the metal excluding lithium in the lithium-nickel-based oxide is 80 mol% or more, 85 mol% or more, 90 mol% or more, 91 mol% or more, or 94 mol% or more and 99 mol% or less. The high-nickel positive electrode active material can achieve high capacity and can be applied to high-capacity, high-density lithium secondary batteries.

[0158] In one embodiment, the lithium nickel-based oxide may be included in an amount of 95% or more by weight of the positive electrode active material, for example, 95 to 100% by weight, 99 to 100% by weight, or 100% by weight.

[0159] The above binder may include one or more of the binders described in the anode above.

[0160] In one embodiment, the binder may include a fluorine-based binder. For example, the fluorine-based binder may include a fluorine-substituted hydrocarbon resin. For example, the fluorine-substituted hydrocarbon resin may include polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), etc.

[0161] The above anode slurry may further include a conductive material.

[0162] The above conductive material may include one or more types of the conductive materials described in the anode above.

[0163] In one embodiment, the conductive material may include one or more of artificial graphite and carbon black.

[0164] The positive active material, conductive material, and binder included in the above positive slurry may comprise 90 to 99 parts by weight of the positive active material, 0.5 to 5 parts by weight of the conductive material, and 0.5 to 5 parts by weight of the binder, based on a total of 100 parts by weight.

[0165] The above anode slurry may further include a dispersion medium.

[0166] The above dispersion medium may include a polar organic solvent, for example, N-methyl-2-pyrrolidone.

[0167] The above dispersion medium may be included in the anode slurry in an amount of 15 to 30 weight percent.

[0168] The solid content of the above anode slurry can be 70 to 85 weight percent.

[0169] The viscosity of the anode slurry may be 1,000 cP to 10,000 cP. Specifically, the viscosity of the anode slurry may be 1,000 cP to 5,000 cP, or 2,000 cP to 4,000 cP. By controlling the amount of dispersion medium added during the preparation of the anode slurry, the slurry can be prepared to satisfy the viscosity range. When the anode slurry satisfies the viscosity range, the anode stabilization effect of the anode additive can be maximized.

[0170] When the viscosity of the anode slurry is within the above range, when the slurry is applied onto the anode current collector, the problem of the slurry being lost does not occur, and the problem of the anode active material layer becoming thick due to an excess amount of slurry being applied does not occur.

[0171] The viscosity of the anode slurry can be measured at room temperature (25°C) using a Type B viscometer. However, the viscometer measuring device is not limited to those described, and any device capable of measuring the viscosity of a liquid can be applied without limitation.

[0172] The method for preparing the above anode slurry can be prepared by the step of mixing the anode active material, binder, conductive material, dispersant, and the compound of Formula 1 as an anode additive.

[0173] Hereinafter, a positive electrode for a lithium secondary battery according to one embodiment of the present invention will be described in more detail.

[0174] The above anode may include an anode active material layer comprising a dried product of the above anode slurry.

[0175] In one embodiment, the anode may include the anode active material and the compound of Formula 1.

[0176] The above anode can be manufactured by the steps of preparing the above anode slurry and coating the above anode slurry onto a current collector to form an anode active material layer.

[0177] In another embodiment of the present invention, a positive electrode comprising a positive active material; and a negative electrode comprising a negative active material, wherein the positive electrode may comprise a positive electrode comprising a dried product of the positive electrode slurry.

[0178] The above-mentioned lithium secondary battery may be applied to automobiles, mobile phones, and / or various types of electric devices, etc., but the present invention is not limited thereto.

[0179] Since the anode above has been described above, a detailed description of the anode slurry and the anode above is omitted.

[0180] In a specific embodiment, the negative electrode active material may include at least one of graphite and a Si composite.

[0181] When the above-mentioned cathode active material includes a Si composite and graphite together, the Si composite and graphite may be included in the form of a mixture, in which case the Si composite:graphite may be included in a weight ratio of 1:99 to 50:50 based on a total of 100 parts by weight. More specifically, the Si composite:graphite may be included in a weight ratio of 3:97 to 20:80, 4:96 to 20:80, or 5:95 to 20:80.

[0182] The above Si composite comprises a core containing Si-based particles and an amorphous carbon coating layer, for example, the Si-based particles are a Si-C composite, SiO x It may include one or more of (0 < x ≤ 2) and Si alloys. For example, the Si-C composite may include a core containing Si particles and crystalline carbon and an amorphous carbon coating layer located on the surface of the core. The crystalline carbon may include, for example, graphite, and more specifically, natural graphite, artificial graphite, or a mixture thereof.

[0183] The above lithium secondary battery may further include an electrolyte.

[0184] The above electrolyte comprises the above-described non-aqueous organic solvent; and a lithium salt.

[0185] The above-mentioned non-aqueous organic solvent may include one or more of the non-aqueous organic solvents described above.

[0186] In one embodiment, the non-aqueous organic solvent may be a mixture containing ethylene carbonate (EC): ethyl methyl carbonate (EMC): dimethyl carbonate (DMC) in a volume ratio of 10 to 30: 10 to 40: 40 to 80. Here, the volume ratio is a value based on 100 volume% of the total of ethylene carbonate (EC): ethyl methyl carbonate (EMC): dimethyl carbonate (DMC). Within the above range, the effect of the additive described below is easily realized, and the battery life can be further improved under high voltage and high temperature conditions in a lithium secondary battery containing a positive electrode active material with a high nickel content described below.

[0187] A lithium salt according to one embodiment of the present invention may include one or more selected from the group consisting of LiPF6, LiClO4, LiBF4, lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), LiSO3CF3, LiBOB, LiFOB, LiDFBP, LiTFOP, LiPO2F2, LiSbF6, LiAsF6, LiAlO2, LiAlCl4, LiCl, LiI, LiN(SO3C2F5)2, Li(FSO2)2N, and LiC4F9SO3. According to one embodiment, LiPF6 may be used as the lithium salt.

[0188] The concentration of the lithium salt may be 0.1M to 3.0M. Specifically, the concentration of the lithium salt may be 0.5M or higher and 1.0M or higher. The concentration of the lithium salt may be 3.0M or lower, 2.5M or lower, and 2.0M or lower. In the present invention, when the concentration of the lithium salt is 0.1M to 2.0M, the conductivity and viscosity of the electrolyte can be appropriately maintained.

[0189] In one embodiment, when the positive electrode comprises a lithium nickel-based oxide and a compound of Formula 1, the effect of improving the high-temperature stability of the lithium secondary battery can be maximized. The operating driving voltage of the lithium secondary battery of the above combination is 4.25V or higher, and it may operate even at high voltage.

[0190] In one embodiment, the lithium secondary battery may be prismatic.

[0191] Examples and comparative examples of the present invention are described below. However, the following examples are merely one example of the present invention, and the present invention is not limited to the following examples.

[0192] Synthesis Example 1

[0193] 142 mmol of 1,2,4-triazole and 214 mmol of sodium bicarbonate were placed in a 1000 ml round-bottom flask with 500 ml of acetonitrile and stirred for 5 minutes, then 71 mmol of bis(vinylsulfonyl)ethane was added and stirred at room temperature (25°C) for 20 hours. After the reaction was complete, the crude was filtered, the filtrate was concentrated and filtered, and then washed with methylene chloride. The obtained solid was vacuum dried to obtain the compound represented by the chemical formula 1-4 below.

[0194] [Chemical Formula 1-4]

[0195]

[0196] Synthesis Example 2

[0197] 50 mmol of methanedisulfonyl dichloride, 200 ml of THF, and 250 mmol of 1,2,4-Triazole are added to an ice bath, and 250 mmol of triethylamine is slowly added dropwise while stirring, followed by stirring at room temperature for 20 hours. After the reaction is complete, the obtained crude is washed with MC (methylene chloride) and water, the MC layer is treated with magnesium sulfate, and then filtered. The filtrate is concentrated and vacuum dried to obtain the compound represented by Chemical Formula 3.

[0198] [Chemical Formula 3]

[0199]

[0200] Examples and Comparative Examples

[0201] Example 1

[0202] (1) Preparation of anode slurry

[0203] LiNi as a positive electrode active material 0.9 Co 0.08 Al 0.02 O298.3 wt%, 0.3 wt% artificial graphite powder and 0.3 wt% carbon black (Ketjenblack) as conductive materials, and 1.1 wt% polyvinylidene fluoride (PVdF) as a binder were mixed, and 0.5 wt% of the compound of Formula 1-4 was mixed with 100 wt% of the cathode active material, and then added to N-methyl-2-pyrrolidone (NMP) and stirred for 30 minutes using a mechanical stirrer to prepare a cathode slurry.

[0204] (2) Manufacturing of lithium secondary batteries

[0205] The above slurry was applied to a thickness of about 60 μm on a 20 μm thick aluminum foil using a doctor blade, dried in a hot air dryer at 100 ℃ for 0.5 hours, dried once more under vacuum conditions at 120 ℃ for 4 hours, and then rolled to produce an anode.

[0206] A cathode slurry was prepared by mixing 98 wt% of a cathode active material, in which a graphite and Si composite was mixed in a weight ratio of 95.8:4.2, 1 wt% of styrene-butadiene rubber (SBR), and 1 wt% of carboxymethylcellulose (CMC), adding the mixture to distilled water, and stirring for 60 minutes using a mechanical stirrer. The slurry was applied to a thickness of about 60 μm on a 10 μm thick copper foil using a doctor blade, dried in a hot air dryer at 100 ℃ for 0.5 hours, dried once more under vacuum conditions at 120 ℃ for 4 hours, and then rolled to produce a cathode.

[0207] An electrode assembly was manufactured by assembling the above positive electrode and the above negative electrode with a separator made of polyethylene material with a thickness of 16 μm, and a prismatic (7Ah class) lithium secondary battery was manufactured by injecting the above electrolyte. The above electrolyte was prepared by dissolving and mixing 1.25 M LiPF6 in a carbonate-based solvent in which ethylene carbonate (EC) : ethyl methyl carbonate (EMC) : dimethyl carbonate (DMC) were mixed in a volume ratio of 20 : 30 : 50 (volume ratio).

[0208] Example 2

[0209] A positive electrode slurry and a battery were prepared in the same manner as in Example 1, except that 1 part by weight of the additive of Formula 1-4 was included with 100 parts by weight of the positive electrode active material in Example 1.

[0210] Example 3

[0211] A positive electrode slurry and a battery were prepared in the same manner as in Example 1, except that 2 parts by weight of the additive of Formula 1-4 were included with respect to 100 parts by weight of the positive electrode active material in Example 1.

[0212] Example 4

[0213] A positive electrode slurry and a battery were prepared in the same manner as in Example 1, except that 5 parts by weight of the additive of Formula 1-4 were included with respect to 100 parts by weight of the positive electrode active material in Example 1.

[0214] Comparative Example 1

[0215] A positive electrode slurry and a battery were prepared in the same manner as in Example 1, except that the compound of Chemical Formula 1-4 above was not included.

[0216] Comparative Example 2

[0217] A positive electrode slurry and a battery were prepared in the same manner as in Example 1, except that 1 part by weight of the additive of Formula 3 was included with 100 parts by weight of the positive electrode active material in Example 1.

[0218]

[0219] Evaluation example

[0220] The lithium secondary battery was evaluated in the following manner.

[0221] Evaluation Example 1 Capacity retention rate after high-temperature storage

[0222] The lithium secondary batteries of the examples and comparative examples were charged at 25°C at 0.33C CC / CV (4.25V, 0.05C CUT-OFF) and discharged at 0.33C CC (2.8V CUT-OFF) twice, and the second discharge capacity C1 was measured. After storing the charged lithium secondary batteries at 60°C for 30 days, they were left at room temperature for an additional 30 minutes, and discharged at 0.33C CC (2.8V CUT-OFF) to measure the discharge capacity C2. The capacity retention rate was calculated using the following formula.

[0223] Capacity retention rate (%) = C2 / C1 × 100.

[0224] Evaluation Example 2: Increase rate of DCIR (direct current internal resistance) after high-temperature storage

[0225] For the lithium secondary batteries according to the examples and comparative examples, the initial DC resistance (DCIR) was measured using the △V / △I (change in voltage / change in current) value, the maximum energy state inside the battery was made to a fully charged state (SOC 100%), and after storing it at 60°C for 30 days in this state, the DC resistance was measured, and the DCIR increase rate (%) was calculated according to the following formula.

[0226] DCIR growth rate (%) = (DCIR after 30 days / Initial DCIR) × 100.

[0227] Evaluation Example 3: Gas generation rate after high-temperature storage

[0228] High-temperature gas generation characteristics were evaluated for lithium secondary batteries according to the examples and comparative examples by measuring the cell thickness increase rate. The initial cell thickness and the cell thickness after storage at 60°C for 14 days were measured, respectively, and the thickness increase rate was calculated according to the following formula.

[0229] [ceremony]

[0230] Thickness increase rate (%) = [(Thickness of cell after storage at 60℃ for 14 days) / (Initial thickness of cell)] × 100.

[0231] Specifically, the thickness of the cell was measured using a Mitutoyo compression-type thickness gauge, with the prismatic cell positioned between compression plates and compressed with a weight of 300g.

[0232] The results of evaluations 1 to 3 are shown in Table 1.

[0233] Additive Capacity Retention Rate (%) DCIR Increase Rate (%) Cell Storage Thickness (cm) Cell Thickness Increase Rate (%) Type Content (parts by weight) * 0 Day 14 Days Example 1 Chemical Formula 1-4 0.5 9 4.6 114.2 10.2 214.18 138.7 Example 2 Chemical Formula 1-4 19 4.8 113.6 10.2 414.05 137.2 Example 3 Chemical Formula 1-4 29 4.9 111.5 10.2 013.58 133.1 Example 4 Chemical Formula 1-4 59 5.1 112.7 10.2 213.47 131.8 Comparative Example 1-- 9 3.1 116.6 10.2 114.6 4143.4 Comparative Example 2 Chemical Formula 3193.8115.710.2514.38140.3

[0234]

[0235] In Table 1, the content of the additive is the content of the additive relative to 100 parts by weight of the content of the cathode active material in the cathode slurry.

[0236]

[0237] synthesis

[0238] Referring to Table 1 above, the positive electrode slurry for a lithium secondary battery of the example can have the effect of improving the lifespan characteristics and stability of the battery by improving the high-temperature life and high-temperature storage performance in the battery.

[0239] However, referring to Table 1 above, the slurry of Comparative Example 1, which does not contain the compound of the present invention, and the slurry of Comparative Example 2, which contains a compound having a heterogeneous structure compared to the compound of the present invention, showed lower effects compared to the example in terms of high-temperature life, high-temperature storage performance, and life characteristics.

[0240]

[0241] Although preferred embodiments of the present invention have been described above, the present invention is not limited thereto and can be implemented with various modifications within the scope of the claims, the detailed description of the invention, and the attached drawings, and it is obvious that such modifications also fall within the scope of the present invention.

Claims

1. Includes a positive electrode active material, a binder, and a positive electrode additive, and The above-mentioned anode additive is an anode slurry for a lithium secondary battery comprising a compound of the following chemical formula 1: [Chemical Formula 1] In the above chemical formula 1 L 1 ... is a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C1 to C20 alkoxylene group, a substituted or unsubstituted C2 to C20 alkenylene group, a substituted or unsubstituted C2 to C20 alkynylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, or a substituted or unsubstituted C2 to C20 heteroarylene group, and L 2 and L 3 Each is independently a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C1 to C20 alkoxylene group, a substituted or unsubstituted C2 to C20 alkenylene group, a substituted or unsubstituted C2 to C20 alkynylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, or a substituted or unsubstituted C2 to C20 heteroarylene group, and R 1 and R 2 Each is an independently substituted or unsubstituted triazole group).

2. The positive electrode slurry for a lithium secondary battery according to claim 1, wherein the above chemical formula 1 is represented by chemical formula 1-1: [Chemical Formula 1-1] In the above chemical formula 1-1, L 4 is a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C1 to C20 alkoxylene group, a substituted or unsubstituted C2 to C20 alkenylene group, a substituted or unsubstituted C2 to C20 alkynylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, or a substituted or unsubstituted C2 to C20 heteroarylene group, and L 5 and L 6 Each is an independently substituted or unsubstituted C1 to C20 alkylene group, R 3 , R 4 , R 5 and R 6 Each is independently hydrogen, a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C1 to C20 alkoxy group, a substituted or unsubstituted C2 to C20 alkenyl group, a substituted or unsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C6 to C20 aryl group, or a substituted or unsubstituted C2 to C20 heteroaryl group.

3. A positive electrode slurry for a lithium secondary battery according to claim 1, wherein the additive of Formula 1 comprises one or more of the following Formulas 1-4 to 1-8: [Chemical Formula 1-4] [Chemical Formula 1-5] [Chemical Formula 1-6] [Chemical Formula 1-7] [Chemical Formula 1-8] .

4. A positive electrode slurry for a lithium secondary battery according to claim 1, wherein the compound of Formula 1 is included in an amount of 0.01 to 10 parts by weight per 100 parts by weight of the positive electrode active material.

5. The positive electrode slurry for a lithium secondary battery according to claim 1, wherein the positive electrode active material comprises a lithium transition metal composite oxide.

6. In claim 5, the lithium nickel-based oxide is a positive electrode slurry for a lithium secondary battery represented by the following chemical formula 2: [Chemical Formula 2] Li a1 Ni x1 M 1 y1 M 2 z1 O 2-b1 X b1 In the above chemical formula 2, 0.9≤a1≤1.8, 0.3≤x1≤1, 0≤y1≤0.7, 0≤z1≤0.7, 0.9≤x1+y1+z1≤1.1, and 0≤b1≤0.1, and M 1 and M 2 Each is independently one or more elements selected from the group consisting of Al, B, Ba, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W, and Zr, and X is one or more elements selected from the group consisting of F, P, and S.

7. A positive electrode slurry for a lithium secondary battery according to claim 6, wherein in the above chemical formula 2, 0 0.8≤x1≤1, 0≤y1≤0.2, and 0≤z1≤0.

2.

8. In paragraph 1, the slurry further comprises a conductive material, and A positive electrode slurry for a lithium secondary battery, comprising, based on a total of 100 parts by weight, 90 to 99 parts by weight of the positive electrode active material, 0.5 to 5 parts by weight of the conductive material, and 0.5 to 5 parts by weight of the binder.

9. A positive electrode for a lithium secondary battery comprising a dried product of a positive electrode slurry for a lithium secondary battery according to any one of claims 1 to 8.

10. A positive electrode; and a negative electrode, comprising The above-mentioned anode is a lithium secondary battery comprising a dried anode slurry of any one of claims 1 to 8.

11. A lithium secondary battery according to claim 10, wherein the cathode comprises a Si composite and graphite as the cathode active material.

12. A lithium secondary battery according to claim 11, wherein the Si composite : graphite is included in a weight ratio of 3 : 97 to 20 :

80.

13. In paragraph 10, the lithium secondary battery further comprises an electrolyte, and The above electrolyte comprises a non-aqueous organic solvent; and a lithium salt, and A lithium secondary battery in which the above-mentioned non-aqueous organic solvent is a mixture containing ethylene carbonate (EC): ethylmethyl carbonate (EMC): dimethyl carbonate (DMC) in a volume ratio of 10 to 30: 10 to 40: 40 to 80.

14. In paragraph 10, the above lithium secondary battery is a prismatic lithium secondary battery.

15. A lithium secondary battery according to claim 10, wherein the operating driving voltage of the lithium secondary battery is 4.25V or higher.

Images