Carbon nanotube dispersion, cathode for secondary battery and secondary battery manufactured by using the same

Abstract

The present invention relates to a dispersion and an anode slurry composition containing the same, and more specifically, to a dispersion capable of efficiently dispersing carbon nanotubes and improving the binding strength of the slurry, an anode slurry composition containing the same, an anode, and a secondary battery.

Description

Technology Field

[0001] The present invention relates to a dispersion containing a copolymer, an anode slurry composition, an anode, and a secondary battery, and more specifically, to an anode slurry composition having excellent dispersibility of carbon nanotubes and a dispersion containing a copolymer capable of producing an electrode with excellent binding strength. Background Technology

[0002] Carbon materials possess unique mechanical, electrical, and thermal properties, so they are used in various fields such as electronics, biotechnology, and medicine. Recently, in addition to conventional carbon materials such as graphite, activated carbon, and carbon black, carbon nanomaterials such as carbon nanotubes, fullerenes, and graphene are gaining attention.

[0003] Meanwhile, to utilize carbon materials efficiently, they must be effectively dispersed within matrices of various materials.

[0004] However, carbon materials, especially carbon nanomaterials, tend to aggregate within the matrix due to strong Van der Waals forces. When carbon materials aggregate within the matrix, they are unable to exhibit their unique properties, and problems such as reduced uniformity may occur.

[0005] Methods for dispersing carbon materials include mechanical dispersion using physical forces such as ultrasound, milling, and high shear force, dispersion using dispersants, and dispersion by surface modification.

[0006] However, there is a problem in that mechanical dispersion and dispersion by surface modification are prone to causing damage to carbon materials, and such damage significantly degrades the inherent properties of the carbon materials (e.g., electrical conductivity, thermal conductivity, etc.).

[0007] Therefore, the dispersion of carbon materials using dispersants is being actively studied, and in particular, research is being intensively conducted on wrapping carbon nanomaterials with polymer dispersants or utilizing the π-π interaction between the p orbitals of the aromatic rings of polymer dispersants and the p orbitals of carbon nanomaterials in order to efficiently disperse carbon nanomaterials such as carbon nanotubes.

[0008] However, there are still not many dispersants capable of efficiently dispersing carbon materials, particularly carbon nanomaterials, while maintaining their inherent properties, so research on this is currently required. Prior art literature

[0009] Republic of Korea Registered Patent No. 10-2465151 The problem to be solved

[0010] The present invention aims to provide a dispersion capable of efficiently dispersing carbon nanotubes and improving the binding strength of a slurry, an anode slurry composition containing the same, an anode, and a secondary battery.

[0011] However, the problems that this invention seeks to solve are not limited to those mentioned above, and other unmentioned problems will be clearly understood by a person skilled in the art from the description below. means of solving the problem

[0012] One aspect of the present invention is,

[0013] Copolymer;

[0014] solvent; and

[0015] Includes carbon nanotubes,

[0016] The copolymer comprises one or more monomer units selected from the group consisting of acrylate-based monomer units comprising one or more substituted or unsubstituted aromatic or aliphatic rings and vinyl-based monomer units comprising one or more substituted or unsubstituted aromatic or aliphatic rings;

[0017] Acrylate-series monomer units comprising linear or branched aliphatic hydrocarbons having 5 to 22 carbon atoms and cyano(CN), pyrrolidone (NC4H6O), carboxylic acid (COOH), amide, alkyl amide, dialkyl amide, alcohol, epoxy group, caprolactam (C5H 10 One or more monomer units selected from the group consisting of polar monomer units comprising one or more selected from the group consisting of CNO), morpholine (C4H8NO), and oxazolidone (C3H4NO2); and

[0018] One or more monomer units selected from the group consisting of acrylate-based monomer units and vinyl acetate-based monomer units comprising linear or branched aliphatic hydrocarbons having 1 to 4 carbon atoms; comprising

[0019] Provides a dispersion.

[0021] Another aspect of the present invention is,

[0022] The above dispersion; and

[0023] Anode active material; comprising,

[0024] Provides an anode slurry composition.

[0026] Another aspect of this institution is,

[0027] The whole house; and

[0028] A positive active material layer formed by applying the positive slurry composition onto the above current collector; comprising

[0029] Provides a positive electrode.

[0031] Another aspect of the present invention is,

[0032] including the above anode,

[0033] Provides a secondary battery. Effects of the invention

[0034] As explained above, the dispersion of the present invention can efficiently disperse carbon nanotubes.

[0035] In addition, the dispersion of the present invention can produce a positive electrode with excellent binding strength between the positive electrode active material and the current collector, thereby preventing the active material from peeling off from the electrode, and thus enabling the production of a secondary battery with excellent lifespan characteristics. Specific details for implementing the invention

[0036] Terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0037] Therefore, it should be understood that the configuration of the embodiments described in this specification is merely one of the most preferred embodiments of the present invention and does not represent all of the technical ideas of the present invention, and that various equivalents and modifications that can replace them may exist at the time of filing this application.

[0038] In this specification, singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as “comprising,” “comprising,” or “having” are intended to specify the existence of the implemented features, numbers, steps, components, or combinations thereof, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, components, or combinations thereof.

[0039] Where various parameters in this specification are given as an enumeration of ranges, preferred ranges, preferred upper limits, and preferred lower limits, it should be understood that any pair of any upper range limit or preferred value and any lower range limit or preferred value specifically discloses all ranges formed by any pair of any upper range limit or preferred value, regardless of whether the range is disclosed separately.

[0040] Where a range of numerical values ​​is mentioned in this specification, unless otherwise stated, the range is intended to include its endpoint and all integers and fractions within that range. The scope of the invention is not intended to be limited to the specific values ​​mentioned when defining the range.

[0041] In the present specification, "a to b" and "a~b" indicating numerical ranges, "to" and "~" are defined as ≥ a and ≤ b.

[0043] A dispersion according to one aspect of the present invention comprises a copolymer, a solvent, and carbon nanotubes, wherein the copolymer comprises one or more monomer units selected from the group consisting of acrylate-based monomer units comprising one or more substituted or unsubstituted aromatic or aliphatic rings and vinyl-based monomer units comprising one or more substituted or unsubstituted aromatic or aliphatic rings; acrylate-based monomer units comprising linear or branched aliphatic hydrocarbons having 5 to 22 carbon atoms and cyano(CN), pyrrolidone (NC4H6O), carboxylic acid (COOH), amide, alkyl amide, dialkyl amide, alcohol, epoxy group, caprolactam (C5H 10It may include one or more monomer units selected from the group consisting of polar monomer units comprising one or more selected from the group consisting of CNO), morpholine (C4H8NO), and oxazolidone (C3H4NO2); one or more monomer units selected from the group consisting of acrylate-based monomer units and vinyl acetate-based monomer units comprising linear or branched aliphatic hydrocarbons having 1 to 4 carbon atoms.

[0045] In one embodiment, any one or more monomer units selected from the group consisting of acrylate-based monomer units comprising one or more substituted or unsubstituted aromatic or aliphatic rings and vinyl-based monomer units comprising one or more substituted or unsubstituted aromatic or aliphatic rings are styrene, cyclopentyl acrylate, cyclohexyl acrylate, benzyl acrylate, 3-phenoxybenzyl acrylate, σ-phenylphenoxyethyl acrylate, σ-phenylphenoxyethyl methacrylate, (1-pyrene) 2-methyl-2-propenoate, and 1-naphthyl Acrylate (1-naphthyl acrylate), 1-naphthyl methacrylate, 2-naphthyl acrylate, 2-naphthyl methacrylate, 9-anthracene methyl acrylate, 9-anthracene methyl methacrylate, or a combination thereof may be polymerized to form.

[0046] Preferably, any one or more monomer units selected from the group consisting of acrylate-based monomer units comprising one or more substituted or unsubstituted aromatic or aliphatic rings and vinyl-based monomer units comprising one or more substituted or unsubstituted aromatic or aliphatic rings may be formed by polymerizing styrene, benzyl acrylate, or a combination thereof.

[0048] In one embodiment, the acrylate-series monomer unit comprising the linear or branched aliphatic hydrocarbon having 5 to 22 carbon atoms is n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-nonyl (meth)acrylate, n-decyl (meth)acrylate, n-undecyl (meth)acrylate, and lauryl (meth)acrylate. (meth)acrylate), n-dodecyl (meth)acrylate, n-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, n-pentadecyl (meth)acrylate, cetyl (meth)acrylate, n-hexadecyl (meth)acrylate, n-heptadecyl (meth)acrylate, stearyl (meth)acrylate, n-nonadecyl (meth)acrylate, n-neicosyl (meth)acrylate, n-heneicosyl (meth)acrylate, n-dococyl (meth)acrylate, iso-pentyl (meth)acrylate,iso-heptyl (meth)acrylate, iso-octyl (meth)acrylate, iso-nonyl (meth)acrylate, iso-decyl (meth)acrylate, iso-undecyl (meth)acrylate, iso-dodecyl (meth)acrylate, iso-tridecyl (meth)acrylate, iso-tetradecyl (meth)acrylate, iso-pentadecyl (meth)acrylate iso-cetyl (meth)acrylate, iso-hexadecyl (meth)acrylate, iso-heptadecyl (meth)acrylate, iso-stearyl (meth)acrylate, iso-nonadecyl (meth)acrylate, iso-eicosyl (meth)acrylate, iso-heneicosyl (meth)acrylate, iso-docosyl (meth)acrylate, or a combination thereof may be formed by polymerization.

[0049] Preferably, the acrylate series monomer unit comprising the linear or branched aliphatic hydrocarbon having 5 to 22 carbon atoms can be formed by polymerizing stearyl acrylate.

[0051] In one embodiment, the cyano(CN), pyrrolidone (NC4H6O), carboxylic acid (COOH), amide, alkyl amide, dialkyl amide, alcohol, epoxy group, caprolactam (C5H 10 Polar monomer units comprising one or more selected from the group consisting of CNO), morpholine (C4H8NO), and oxazolidone (C3H4NO2) may be formed by polymerizing acrylonitrile, vinyl pyrrolidone, acrylic acid, methacrylic acid, itaconic acid, acrylamide, N-methyl acylamide, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate, or a combination thereof.

[0052] Preferably, the cyano(CN), pyrrolidone (NC4H6O), carboxylic acid (COOH), amide, alkyl amide, dialkyl amide, alcohol, epoxy group, caprolactam (C5H 10 Polar monomer units comprising one or more selected from the group consisting of CNO), morpholine (C4H8NO), and oxazolidone (C3H4NO2) can be formed by polymerizing acrylic acid.

[0054] In one embodiment, the acrylate-series monomer unit comprising the linear or branched aliphatic hydrocarbon having 1 to 4 carbon atoms may be formed by polymerizing methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, or a combination thereof, and the vinyl acetate-series monomer unit may be formed by polymerizing vinyl acetate.

[0055] One or more monomer units selected from the group consisting of acrylate-based monomer units and vinyl acetate-based monomer units containing linear or branched aliphatic hydrocarbons having 1 to 4 carbon atoms have a binding strength enhancing effect and, because they have short carbon chains, have high polarity, causing the copolymer to dissolve well in a solvent. That is, when a dispersion solution is used in which a copolymer formed by polymerizing the monomers is used as a dispersant, compared to when the monomers are not included, the dispersibility of the carbon material and the bonding strength between the positive active material and the current collector are excellent, so that the positive active material can be prevented from peeling off from the electrode, thereby enabling the manufacture of a secondary battery with excellent lifespan characteristics.

[0057] In one embodiment, the copolymer is formed by polymerizing styrene, stearyl acrylate, acrylic acid, and methyl acrylate; or by polymerizing styrene, stearyl acrylate, acrylic acid, and methyl methacrylate; or by polymerizing styrene, stearyl acrylate, acrylic acid, and ethyl acrylate; or by polymerizing styrene, stearyl acrylate, acrylic acid, and ethyl methacrylate; or by polymerizing styrene, stearyl acrylate, acrylic acid, and butyl acrylate; or by polymerizing styrene, stearyl acrylate, acrylic acid, and butyl methacrylate; or by polymerizing styrene, stearyl acrylate, It can be formed by polymerizing acrylic acid and vinyl acetate, or by polymerizing benzyl acrylate, styrene, stearyl acrylate, acrylic acid and methyl acrylate.

[0059] In one embodiment, the copolymer comprises, based on 100 mol% of the copolymer, 1 mol% or more and 60 mol% or less of an acrylate-based monomer unit comprising one or more substituted or unsubstituted aromatic or aliphatic rings, one or more monomer units selected from the group consisting of a vinyl-based monomer unit comprising one or more substituted or unsubstituted aromatic or aliphatic rings; 5 mol% or more and 80 mol% or less of an acrylate-based monomer unit comprising a linear or branched aliphatic hydrocarbon having 5 to 22 carbon atoms, and cyano(CN), pyrrolidone (NC4H6O), carboxylic acid (COOH), amide, alkyl amide, dialkyl amide, alcohol, epoxy group, caprolactam (C5H 10 It may include one or more monomer units selected from the group consisting of polar monomer units comprising one or more selected from the group consisting of CNO), morpholine (C4H8NO), and oxazolidone (C3H4NO2); and one or more monomer units selected from the group consisting of acrylate-based monomer units and vinyl acetate-based monomer units comprising linear or branched aliphatic hydrocarbons having 1 to 4 carbon atoms in an amount of 5 mol% or more and 40 mol% or less.

[0061] For example, based on 100 mol% of the copolymer, the copolymer may contain one or more monomer units selected from the group consisting of acrylate-based monomer units containing one or more substituted or unsubstituted aromatic or aliphatic rings and vinyl-based monomer units containing one or more substituted or unsubstituted aromatic or aliphatic rings, in an amount of 1 mol% or more, 60 mol% or less, 5 mol% or more, 50 mol% or less, or 10 mol% or more, 40 mol% or less. However, either the content of the acrylate-based monomer units or the content of the vinyl-based monomer units may be 0 mol%. If the content of one or more monomer units selected from the group consisting of acrylate-based monomer units containing one or more substituted or unsubstituted aromatic or aliphatic rings and vinyl-based monomer units containing one or more substituted or unsubstituted aromatic or aliphatic rings is below the range of the present invention, the interaction between the carbon nanotube and the copolymer chain is weakened, making it difficult to perform the role of dispersion, and if it exceeds the range of the present invention, the viscosity of the dispersion may become excessively high.

[0062] Additionally, for example, the copolymer may contain, based on 100 mol% of the copolymer, acrylate-based monomer units containing linear or branched aliphatic hydrocarbons having 5 to 22 carbon atoms in an amount of 5 mol% or more, 80 mol% or less, 10 mol% or more, 70 mol% or less, 15 mol% or more, 60 mol% or less, or 20 mol% or more, 50 mol% or less. If the content of acrylate-based monomer units containing linear or branched aliphatic hydrocarbons having 5 to 22 carbon atoms is below the range of the present invention, it may be difficult for the copolymer to wrap carbon nanotubes, and if it exceeds the range of the present invention, the copolymer may not dissolve in the solvent and precipitate or phase separation may occur.

[0063] And, for example, based on 100 mol% of the copolymer, the copolymer comprises cyano(CN), pyrrolidone (NC4H6O), carboxylic acid (COOH), amide, alkyl amide, dialkyl amide, alcohol, epoxy group, caprolactam (C5H 10 It may contain one or more polar monomer units selected from the group consisting of CNO), morpholine (C4H8NO), and oxazolidone (C3H4NO2) in an amount of 0 mol% or more, 60 mol% or less, 0 mol% or more, 50 mol% or less, or 0 mol% or more, 40 mol% or less. The above cyano(CN), pyrrolidone (NC4H6O), carboxylic acid (COOH), amide, alkyl amide, dialkyl amide, alcohol, epoxy group, caprolactam (C5H 10 If the content of a polar monomer unit comprising one or more selected from the group consisting of CNO, morpholine (C4H8NO), and oxazolidone (C3H4NO2) is below the range of the present invention, the copolymer may not dissolve in the solvent and may precipitate or undergo phase separation; if it exceeds the range of the present invention, the glass transition temperature becomes excessively high, and when an electrode is manufactured, the electrode may not be flexible and may break.

[0064] For example, based on 100 mol% of the copolymer, the copolymer may contain one or more monomer units selected from the group consisting of acrylate-based monomer units containing linear or branched aliphatic hydrocarbons having 1 to 4 carbon atoms and vinyl acetate-based monomer units in an amount of 5 mol% or more, 40 mol% or less, 15 mol% or more, 40 mol% or less, or 20 mol% or more, 40 mol% or less. If the content of one or more monomer units selected from the group consisting of acrylate-based monomer units containing linear or branched aliphatic hydrocarbons having 1 to 4 carbon atoms and vinyl acetate-based monomer units is below the range of the present invention, the binding strength enhancing effect is reduced, and delamination from the current collector may occur; if it exceeds the range of the present invention, the content of other monomers related to dispersibility is reduced, and the dispersibility of carbon nanotubes may be significantly reduced.

[0066] In one embodiment, the copolymer may be represented by the following chemical formula 1.

[0068] [Chemical Formula 1]

[0069]

[0071] In the above chemical formula 1,

[0072] R1 to R 18 They are the same or different from each other, and each independently is hydrogen, a linear or branched hydrocarbon having 1 to 4 carbon atoms, and

[0073] R1' is a linear or branched aliphatic hydrocarbon having 5 to 22 carbon atoms, and

[0074] R2' comprises one or more substituted or unsubstituted aromatic or aliphatic rings, and

[0075] R3' comprises one or more substituted or unsubstituted aromatic or aliphatic rings, and

[0076] R4' is cyano(CN), pyrrolidone (NC4H6O), carboxylic acid (COOH), amide, alkyl amide, dialkyl amide, alcohol, epoxy group, caprolactam (C5H 10 One or more selected from the group consisting of CNO), morpholine (C4H8NO), and oxazolidone (C3H4NO2), and

[0077] R5' and R6' are each independently linear or branched aliphatic hydrocarbons having 1 to 4 carbon atoms, and

[0078] l+m+n+o+p+q=1, and 0.05≤l+o≤0.80, 0.01≤m+n≤0.60, and 0.05≤p+q≤0.40.

[0079] (However, either m or n can be 0, either p or q can be 0, and o can be 0.)

[0081] In one embodiment, R1 to R in Chemical Formula 1 18 All of them can be hydrogen.

[0083] In one embodiment, R1' in Formula 1 is n-pentyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, n-undecyl, lauryl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, cetyl, n-hexadecyl, n-heptadecyl, stearyl, n-octadecyl, n-nonadecyl, n-icosyl, n-henicosyl, n-docosyl, iso-pentyl, iso-heptyl, iso-octyl, iso-nonyl, iso-decyl, iso-undecyl, iso-dodecyl, iso-tridecyl, iso-tetradecyl, iso-pentadecyl, iso-cetyl, iso-hexadecyl, iso-heptadecyl, iso-stearyl, iso-octadecyl, It may include one or more selected from the group consisting of iso-nonadecil, iso-icocil, iso-henicocil, and iso-docosil.

[0084] Preferably, R1' in the above chemical formula 1 may be n-octadecyl.

[0086] In one embodiment, R2' and R3' in the above formula 1 may be the same or different from each other and may each include one or more selected from the group consisting of cyclopentyl, cyclohexyl, benzyl, phenyl, phenoxy, naphthalene, anthracene, and pyrene, which are independently substituted or unsubstituted.

[0087] Preferably, in the above formula 1, R1' is benzyl, phenyl, naphthalene, or 3-phenoxybenzyl group, and R3' may be a phenyl group.

[0089] In one embodiment, R4' in Chemical Formula 1 may preferably be a carboxylic acid (COOH).

[0091] In one embodiment, R5' and R6' in Formula 1 may be the same or different from each other and may each independently include one or more selected from the group consisting of hydrogen, methyl, ethyl, propyl, iso-propyl, n-butyl, iso-butyl, and sec-butyl.

[0092] Preferably, in the above formula 1, R5' may be a methyl group, an ethyl group, or an n-butyl group, and R6' may be a methyl group.

[0094] In one embodiment, the monomer comprising R1' in Formula 1 is n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-nonyl (meth)acrylate, n-decyl (meth)acrylate, n-undecyl (meth)acrylate, lauryl (meth)acrylate, n-dodecyl (meth)acrylate, n-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, n-pentadecyl (meth)acrylate, cetyl (meth)acrylate, n-hexadecyl (meth)acrylate, n-heptadecyl (meth)acrylate, stearyl (meth)acrylate, n-nonadecyl (meth)acrylate, n-neicosyl (meth)acrylate), n-heneicosyl (meth)acrylate, n-dococyl (meth)acrylate, iso-pentyl (meth)acrylate,iso-heptyl (meth)acrylate, iso-octyl (meth)acrylate, iso-nonyl (meth)acrylate, iso-decyl (meth)acrylate, iso-undecyl (meth)acrylate, iso-dodecyl (meth)acrylate, iso-tridecyl (meth)acrylate, iso-tetradecyl (meth)acrylate, iso-pentadecyl (meth)acrylate It may be iso-cetyl (meth)acrylate, iso-hexadecyl (meth)acrylate, iso-heptadecyl (meth)acrylate, iso-stearyl (meth)acrylate, iso-nonadecyl (meth)acrylate, iso-eicosyl (meth)acrylate, iso-heneicosyl (meth)acrylate, iso-docosyl (meth)acrylate, or copolymers thereof, but is not limited thereto.

[0095] Preferably, the monomer containing R1' in the above formula 1 may be stearyl acrylate.

[0097] In one embodiment, the monomer comprising R2' in Formula 1 is cyclopentyl acrylate, cyclohexyl acrylate, benzyl acrylate, 3-phenoxybenzyl acrylate, σ-phenylphenoxyethyl acrylate, σ-phenylphenoxyethyl methacrylate, (1-pyrene) 2-methyl-2-propenoate, 1-naphthyl acrylate, 1-naphthyl methacrylate, 2-naphthyl acrylate, 2-naphthyl acrylate, 2-naphthyl It may be one or more selected from the group consisting of methacrylate (2-naphthyl methacrylate), 9-anthracene methyl acrylate, and 9-anthracene methyl methacrylate, and the monomer containing R3' may be styrene.

[0098] Preferably, the monomer containing R1' in Formula 1 above may be benzyl acrylate, 1-naphthyl acrylate, 1-naphthyl methacrylate, 2-naphthyl acrylate, 2-naphthyl methacrylate, or 3-phenoxybenzyl acrylate.

[0100] In one embodiment, the monomer comprising R4' in Formula 1 may be one or more selected from the group consisting of acrylonitrile, vinyl pyrrolidone, acrylic acid, methacrylic acid, itaconic acid, acrylamide, N-methyl acylamide, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, and glycidyl methacrylate.

[0101] Preferably, the monomer containing R4' in the above chemical formula 1 may be acrylic acid.

[0103] In one embodiment, the monomer containing R5' in Formula 1 may be one or more selected from the group consisting of methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, and butyl methacrylate, and the monomer containing R6' may be vinyl acetate.

[0105] In one embodiment, the solvent included in the dispersion may be a polar solvent and may be, for example, one or more selected from the group consisting of N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone (NEP), dimethylformamide (DMF), dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), γ-butyrolactone, ethyl acetate, propyl acetate, ethanol, isopropyl alcohol, and deionized water.

[0107] In one embodiment, the copolymer may be a random copolymer or a block copolymer depending on the synthesis process.

[0109] In one embodiment, the number average molecular weight of the copolymer may be 8,000 or more and 40,000 or less.

[0110] For example, the number average molecular weight of the copolymer may be 8,000 or more, 35,000 or less, 8,000 or more, 30,000 or less, 8,000 or more, 25,000 or less, 8,000 or more, 20,000 or less, 9,000 or more, and 20,000 or less.

[0111] If the number average molecular weight of the copolymer falls below the range of the present invention, the fluidity of the copolymer increases, which may reduce the ability to prevent the re-aggregation of carbon materials within the dispersion, and if the number average molecular weight exceeds the range of the present invention, the viscosity becomes excessively high, which may reduce usability.

[0113] In one embodiment, the carbon nanotubes included in the dispersion may be single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes, or a combination thereof.

[0114] In addition, the carbon nanotubes may be included in an amount of 1% or more and 10% or less based on 100% by weight of the total weight of the dispersion.

[0115] If the content of carbon nanotubes in the dispersion is below the range of the present invention, the solid content of the electrode slurry is low, and if it exceeds the range of the present invention, the viscosity is too high and dispersion is poor, making it difficult to produce a high-quality dispersion.

[0117] Meanwhile, the content of the copolymer in the dispersion may be 0.1 to 0.5 times the content of the carbon nanotube.

[0118] If the content of the copolymer relative to the carbon nanotube content falls below the range of the present invention, a sufficient dispersion effect cannot be obtained, and the carbon material cannot be efficiently dispersed. Furthermore, if the content of the copolymer relative to the carbon nanotube content exceeds the range of the present invention, the proportion of the internal battery material increases, which may lead to a decrease in energy density.

[0120] In one embodiment, the dispersion may have a viscosity of 7000 cps or less at a shear rate of 2.5 / s.

[0121] For example, the viscosity of the above dispersion at a shear rate of 2.5 / s may be 1000 cps or more and 7000 cps or less.

[0123] In one embodiment, the particle size (D50) of the carbon nanotubes dispersed in the dispersion may be 18 μm or less.

[0124] That is, the dispersion containing the copolymer of the present invention has a low particle size value (D50) of 10 μm or less, so the dispersibility of carbon nanotubes in the dispersion is excellent.

[0125] For example, the particle size (D50) of the carbon nanotubes dispersed in the dispersion may be 2 μm or more and 18 μm or less.

[0127] That is, the copolymer (dispersant) of the present invention, based on excellent dispersion power, can reduce the particle size of carbon nanotubes in the dispersion to produce a carbon material dispersion with uniform and dense particle size and low viscosity, and accordingly, the dispersion process time can be shortened.

[0129] In another aspect of the present invention, the anode slurry composition may include the dispersion and the anode active material.

[0131] In one embodiment, the content of the carbon nanotubes included in the anode slurry composition may be 0.001 to 0.1 times the content of the anode active material, and preferably 0.003 to 0.02 times.

[0132] If the content of carbon nanotubes included in the anode slurry composition relative to the anode active material content is below the range of the present invention, the conductivity within the electrode active material may be reduced, and the output characteristics may be reduced; if it exceeds the range of the present invention, the content of the anode active material may be lowered, and the battery capacity may be reduced.

[0134] In one embodiment, the positive electrode active material may be any positive electrode active material available in the art. Specific examples of such positive electrode active materials include lithium metal; lithium cobalt-based oxides such as LiCoO2; Li 1+x Mn 2-xLithium manganese oxides such as O4 (where x is 0 to 0.33), LiMnO3, LiMn2O3, LiMnO2, etc.; lithium copper oxides such as Li2CuO2; vanadium oxides such as LiV3O8, V2O5, Cu2V2O7, etc.; LiNi 1-x M x Lithium nickel-based oxide represented by O2 (where M=Co, Mn, Al, Cu, Fe, Mg, B, or Ga, and x=0.01 to 0.3); LiMn 2-x M x Lithium manganese composite oxide represented by O2 (where M=Co, Ni, Fe, Cr, Zn, or Ta, and x=0.01 to 0.1) or Li2Mn3MO8 (where M=Fe, Co, Ni, Cu, or Zn); Li(Ni a Co b Mn c Examples include lithium-nickel-manganese-cobalt oxides represented by )O2 (where 0<a<1, 0<b<1, 0<c<1, a+b+c=1); sulfur or disulfide compounds; phosphates such as LiFePO4, LiMnPO4, LiCoPO4, LiNiPO4; Fe2(MoO4)3, but are not limited to these.

[0135] The above positive active material may be included in an amount of 90 to 99 weight percent based on solid content. If the content of the active material is low, the battery cannot produce a high capacity, and if the content of the active material is excessively high, the content of binder, conductive material, etc. becomes relatively low, so electrode adhesion and conductivity may be reduced.

[0137] In one embodiment, the anode slurry composition may additionally include a conductive material.

[0138] The above conductive material is not particularly limited and can be appropriately selected depending on the type of battery and capacitor. For example, in the case of a lithium-ion secondary battery, carbon such as graphite or activated carbon is used, and in the case of a nickel-hydrogen secondary battery, cobalt oxide is used, and nickel powder, cobalt oxide, titanium oxide, carbon, etc. can be used for the negative electrode.

[0139] Examples of the above carbons include acetylene black, furnace black, graphite, carbon fiber, and fullerenes.

[0140] The amount of the conductive material used is typically 1 to 20 weight%, preferably 2 to 10 weight%, based on 100 weight% of the electrode active material.

[0141] Since reducing the content of conductive material and increasing the content of cathode active material can improve the energy density of a secondary battery, it is important to achieve high efficiency even when using the same amount of conductive material.

[0142] When conductive materials used in electrode slurries for secondary batteries are dispersed in small and uniform sizes, the conductivity efficiency increases, which lowers resistance within the battery, exhibits improved output characteristics, and enhances lifespan characteristics. If they are dispersed in large and non-uniform sizes, even when the same amount is used, the binding characteristics and conductivity decrease, which adversely affects the battery's lifespan and output characteristics. Additionally, if the viscosity of the dispersion is low, the solid content of the slurry can be increased, thereby improving the electrode production speed.

[0144] In one embodiment, the anode slurry composition may additionally include a binder.

[0145] The above binder may be selected from one or more of poly(meth)acrylic acid, poly(meth)acrylamide, carboxymethylcellulose, polyvinylidene fluoride, a copolymer of polyhexafluoropropylene-polyvinylidene fluoride (P(VdF / HFP)), poly(vinyl acetate), polyvinyl alcohol, polyethylene oxide, polyvinylpyrrolidone, alkylated polyethylene oxide, polyvinyl ether, poly(methyl methacrylate), poly(ethyl acrylate), polytetrafluoroethylene, polyvinyl chloride, polyacrylonitrile, polyvinylpyridine, styrene-butadiene rubber, acrylonitrile-butadiene rubber, and copolymers thereof, but is not limited thereto.

[0146] The content of the above binder in the anode slurry composition may be 0.3 weight% or more and 10 weight% or less based on the solid content. Preferably, the content of the above binder in the anode slurry composition may be 0.7 weight% or more and 8 weight% or less.

[0147] If the content of the binder is below the range of the present invention, it may be difficult to expect sufficient binding force between the current collector and the positive active material or between the positive active materials, and if the content of the binder exceeds the range of the present invention, the binder acts as a resistor within the battery, and the relative content of the positive active material decreases, which may lead to a decrease in battery capacity and other degraded battery performance.

[0149] According to another aspect of the present invention, the anode may include a current collector; and an anode active material layer formed by applying the anode slurry composition.

[0150] The above anode can be manufactured through the steps of (a) preparing an anode slurry composition comprising an anode active material and a copolymer of the present invention, and (b) applying the anode slurry composition onto an anode current collector and drying it.

[0151] The above anode slurry composition can be mixed by stirring in a conventional manner using a conventional mixer, such as a high-speed shear mixer, a homo mixer, etc.

[0152] The above step (b) is a step of manufacturing a positive electrode for a lithium secondary battery by applying the positive electrode slurry composition prepared in step (a) onto a positive electrode current collector and then drying it.

[0153] At this time, there are no limitations on the method of applying the anode slurry composition, and it can be manufactured by performing, for example, doctor blade coating, dip coating, gravure coating, slit die coating, spin coating, comma coating, bar coating, reverse roll coating, screen coating, cap coating, etc.

[0154] A positive electrode for a secondary battery can be manufactured by applying and drying the above positive electrode slurry composition to finally form a positive electrode active material layer.

[0155] The above current collector can be used as long as it is conductive and does not chemically react with the electrode forming slurry. Typical examples include aluminum foil and copper foil. A current collector with a thickness between 3 and 50 micrometers can be selected and used.

[0157] In one embodiment, the anode prepared using an anode slurry composition comprising 5 parts by weight or more and 10 parts by weight or less of the dispersion based on 100 parts by weight of the total weight of the anode slurry composition may have a bonding force between the current collector and the anode active material layer of 4.7 gf / mm or more.

[0158] That is, the positive active material layer formed by applying the positive slurry composition containing the copolymer of the present invention has excellent adhesion with the current collector, with an adhesion strength of 4.7 gf / mm or more, which can prevent the phenomenon of electrode detachment, and accordingly, the lifespan of the secondary battery with excellent lifespan characteristics can be improved.

[0160] A secondary battery according to another aspect of the present invention may include the above positive electrode.

[0162] In one embodiment, the secondary battery may further include a separator.

[0163] The separator must be an insulator capable of separating the negative and positive electrodes and must provide a pathway for the movement of only lithium ions. To achieve this, it must have good wettability with respect to the electrolyte, and porous polymer films such as PE / PP or porous nonwoven fabrics are used. To prevent battery short circuits, coated separators coated with materials such as ceramics that enhance heat resistance and mechanical strength may be used, and they can be coated in a single layer or multiple layers.

[0164] The above-mentioned separator may be made of a porous substrate, and any porous substrate typically used in electrochemical devices may be used; for example, a polyolefin-based porous membrane or a nonwoven fabric may be used, but is not specifically limited thereto.

[0165] The above separator may be a porous substrate composed of any one selected from the group consisting of polyethylene, polypropylene, polybutylene, polypentene, polyethylene terephthalate, polybutylene terephthalate, polyester, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenylene oxide, polyphenylene sulfide, and polyethylene naphthalate, or a mixture of two or more of these.

[0166] The electrolyte of the above-mentioned lithium secondary battery is a non-aqueous electrolyte containing a lithium salt, composed of a lithium salt and a solvent, and the solvent used is a non-aqueous organic solvent, an organic solid electrolyte, and an inorganic solid electrolyte.

[0167] The above lithium salt is a substance that dissolves well in the above-mentioned non-aqueous electrolyte, for example, LiCl, LiBr, LiI, LiClO4, LiBF4, LiB 10 Cl 10 LiPF6, LiAsF6, LiSbF6, LiAlCl4, LiSCN, LiC4BO8, LiCF3CO2, LiCH3SO3, LiCF3SO3, LiN(SO2CF3)2, LiN(SO2F)2, LiN(SO2C2F5)2, LiC4F9SO3, LiC(CF3SO2)3, (CF3SO2)·2NLi, lithium chloroborane, lithium lower aliphatic carboxylate, lithium 4-phenylborate imide, etc. may be used.

[0168] The above-mentioned non-aqueous organic solvent is, for example, N-methyl-2-pyrrolidone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, gamma-butyrolactone, 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydroxyfranc, 2-methyl tetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, 4-methyl-1,3-dioxene, diethyl ether, formamide, dimethylformamide, dioxolane, acetonitrile, nitromethane, methyl formate, methyl acetate, phosphate triester, trimethoxymethane, dioxolane derivative, sulfolane, methylsulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate derivative, Aprotic organic solvents such as tetrahydrofuran derivatives, ethers, methyl propionate, and ethyl propionate may be used.

[0169] The above organic solid electrolyte may be, for example, a polyethylene derivative, a polyethylene oxide derivative, a polypropylene oxide derivative, a phosphate ester polymer, agitation lysine, polyester sulfide, polyvinyl alcohol, polyvinylidene fluoride, a polymer containing a secondary dissociating group, etc.

[0170] As the above-mentioned inorganic solid electrolyte, for example, nitrides, halides, sulfates of Li such as Li3N, LiI, Li5NI2, Li3N-LiI-LiOH, LiSiO4, LiSiO4-LiI-LiOH, Li2SiS3, Li4SiO4, Li4SiO4-LiI-LiOH, Li3PO4-Li2S-SiS2, etc., may be used.

[0171] In addition, non-aqueous electrolytes may further include other additives for the purpose of improving charge / discharge characteristics, flame retardancy, etc. Examples of the above additives include pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, n-glyme, hexaphosphate trialamide, nitrobenzene derivative, sulfur, quinone imine dye, N-substituted oxazolidinone, N,N-substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salt, pyrrole, 2-methoxyethanol, aluminum trichloride, fluoroethylene carbonate (FEC), propene sulfone (PRS), vinylene carbonate (VC), etc.

[0173] The lithium secondary battery according to the present invention enables lamination stacking and folding processes of the separator and electrode in addition to the general winding process. Furthermore, the battery case may be cylindrical, prismatic, pouch-type, or coin-type. In addition, such a lithium secondary battery can be used in small to medium-to-large models, such as automobiles and electronic devices.

[0175] The present invention will be explained in more detail below through examples. However, the following examples are intended to explain the invention more specifically, and the scope of the invention is not limited by the following examples.

[0177] Examples and Comparative Examples: Preparation of Copolymers

[0178] [Example 1]

[0179] 70 g of N-methyl pyrrolidone (NMP) was placed in a 5-neck flask reactor as a solvent, and 21 mol% of styrene (SM), 28 mol% of stearyl acrylate (SA), 21 mol% of acrylic acid (AA), and 30 mol% of methyl acrylate (MA) were added based on 100 mol% of the total molar amount of monomers to be copolymerized. Then, a reflux condenser and a thermometer were installed, and the temperature was raised to 75 ℃ while purging with nitrogen to prepare a solution. At this time, the total weight of the monomers to be copolymerized was set to 70 g.

[0180] Then, 0.15 g of 2,2'-azobis-2,4-dimethyl valeronitrile was dissolved in 20 g of N-methylpyrrolidone and added dropwise to the solution over 30 minutes, and the copolymer was prepared by maintaining the temperature at 75°C for 7 hours after the addition was completed.

[0182] [Example 2]

[0183] A copolymer was prepared in the same manner as in Example 1, except that 30 mol% of methyl methacrylate (MMA) was used instead of 30 mol% of methyl acrylate (MA).

[0185] [Example 3]

[0186] A copolymer was prepared in the same manner as in Example 1, except that 30 mol% of ethyl acrylate (EA) was used instead of 30 mol% of methyl acrylate (MA).

[0188] [Example 4]

[0189] A copolymer was prepared in the same manner as in Example 1, except that 30 mol% of ethyl methacrylate (EMA) was used instead of 30 mol% of methyl acrylate (MA).

[0191] [Example 5]

[0192] A copolymer was prepared in the same manner as in Example 1, except that 30 mol% of butyl acrylate (BA) was used instead of 30 mol% of methyl acrylate (MA).

[0194] [Example 6]

[0195] A copolymer was prepared in the same manner as in Example 1, except that 30 mol% of butyl methacrylate (BMA) was used instead of 30 mol% of methyl acrylate (MA).

[0197] [Example 7]

[0198] A copolymer was prepared in the same manner as in Example 1, except that 30 mol% of vinyl acetate (VAc) was used instead of 30 mol% of methyl acrylate (MA).

[0200] [Example 8]

[0201] A copolymer was prepared in the same manner as in Example 1, except that 10.5 mol% of styrene (SM) and 10.5 mol% of benzyl acrylate (BzA) were used instead of 21 mol% of styrene (SM).

[0203] [Comparative Example 1]

[0204] A copolymer was prepared in the same manner as in Example 1, except that methyl acrylate (MA) was not used, styrene (SM) was used at 30 mol% instead of 21 mol%, stearyl acrylate (SA) was used at 40 mol% instead of 28 mol%, and acrylic acid (AA) was used at 30 mol% instead of 21 mol%.

[0206] [Comparative Example 2]

[0207] A copolymer was prepared in the same manner as in Example 1, except that 100 mol% of ethyl acrylate (EA) was used, and styrene (SM), stearyl acrylate (SA), and acrylic acid (AA) were not used.

[0209] Table 1 below shows the content (mol%) of the monomers used to prepare the copolymers of Examples 1 to 8 and Comparative Examples 1 and 2.

[0211] Monomer content (mol%) BzA SM SA AA MA MMA EA EMA BA BMA VAc Example 1 - 21 28 21 30 - - - - - - Example 2 - 21 28 21 - 30 - - - - - Example 3 - 21 28 21 - - 30 - - - - Example 4 - 21 28 21 - - - 30 - - - Example 5 - 21 28 21 - - - - 30 - - Example 6 - 21 28 21 - - - - 30 Example 7 - 21 28 21 - - - - - - 30 Example 8 10.5 10.5 28 21 30 - - - - - - Comparative Example 1 - 30 40 30 - - - - - - - Comparative Example 2 - - - - - - 100 - - - -

[0213] In Table 1 above, BzA represents benzyl acrylate, SM represents styrene, SA represents stearyl acrylate, AA represents acrylic acid, MA represents methyl acrylate, MMA represents methyl methacrylate, EA represents ethyl acrylate, EMA represents ethyl methacrylate, BA represents butyl acrylate, BMA represents butyl methacrylate, and VAc represents vinyl acetate.

[0215] [Preparation Example]

[0216] Preparation Examples 1 to 8, Comparative Preparation Examples 1 and 2: Preparation of dispersions

[0217] 0.75 g of the copolymer prepared in Examples 1 to 8 and Comparative Examples 1 and 2, 3 g of multi-walled carbon nanotubes (MWCNT), 96.25 g of N-methylpyrrolidone, and 400 g of zirconia beads with an average diameter of 0.65 mm were fed into a plantary ball mill and dispersed at 400 rpm for 60 minutes, and the zirconia bead mixture was filtered through a 40 mesh to prepare a dispersion with a solid content of 3.75 wt%.

[0218] Table 2 below shows the types of copolymers included in the dispersions of Preparation Examples 1 to 8 and Comparative Preparation Examples 1 and 2.

[0220] dispersion copolymer containing a dispersion Preparation Example 1 Example 1 Preparation Example 2 Example 2 Preparation Example 3 Example 3 Preparation Example 4 Example 4 Preparation Example 5 Example 5 Preparation Example 6 Example 6 Preparation Example 7 Example 7 Preparation Example 8 Example 8 Comparative Manufacturing Example 1 Comparative Example 1 Comparative Manufacturing Example 2 Comparative Example 2

[0222] [Evaluation Example]

[0223] Evaluation Example 1: Measurement of viscosity and particle size of dispersion

[0224] The viscosity of the dispersions of Preparation Examples 1 to 8 and Comparative Preparation Examples 1 and 2 was measured using a Haake Mars rheometer. The shear rate was measured in the range of 0.01 / s to 200 / s.

[0225] The particle size of the dispersions of Preparation Examples 1 to 8 and Comparative Preparation Examples 1 and 2 was measured using a Mastersizer 3000 with the Fraunhofer diffraction model.

[0226] The viscosity values ​​and D50 (median value) at a shear rate of 2.5 / s are shown in Table 3 below.

[0228] dispersion Viscosity @shear rate 2.5 / s(cPs) Particle size (D50, μm) Preparation Example 1 1084.4 2.91 Preparation Example 2 1138.1 3.07 Preparation Example 3 1387.9 3.96 Preparation Example 4 1402.6 4.52 Preparation Example 5 1391.7 4.33 Preparation Example 6 1533.2 5.52 Preparation Example 7 1243.6 4.79 Preparation Example 8 1149.0 3.14 Comparative Manufacturing Example 1 834.19 2.69 Comparative Manufacturing Example 2 7485.4 19.08

[0230] The viscosity of Comparative Example 2, which contains methyl acrylate alone, was very high at 7485.4 cPs, confirming that a dispersion containing a polymer prepared using a monomer that increases the binding strength of the electrode, such as methyl acrylate alone, significantly increases the viscosity of the dispersion.

[0232] Evaluation Example 2: Measurement of Anode Bonding Strength

[0233] A cathode slurry composition was prepared by mixing 4.6 g of dispersions from Preparation Examples 1 to 8 and Comparative Preparation Examples 1 and 2, 27.3 g of cathode active material (NCM811), 18 g of polyvinylidene fluoride (PVdF) dissolved in N-methylpyrrolidone at 8 wt%, and 7.9 g of N-methylpyrrolidone using a Planetary centrifugal mixer (ARE-210, Thinky). At this time, the solid content of the slurry was 50 wt%.

[0234] The prepared anode slurry composition was applied onto an aluminum foil with a thickness of 20 μm using a doctor blade. The electrode coated with the anode slurry composition was dried in an oven at 130°C for 12 hours and then rolled to achieve a composite density of 2.4 g / cc. Subsequently, vacuum drying was performed at 110°C to produce the anode.

[0235] The manufactured anode was made with a width of 20 mm, and the bonding strength between the aluminum foil and the coating, that is, between the current collector and the coating layer of the anode slurry composition, was measured using a Universal Testing Machine (UTM).

[0236] The measured bonding strength of the anodes is shown in Table 4 below.

[0238] Anode (type of dispersion) Bonding strength (gf / mm) Preparation Example 1 5.36 Preparation Example 2 5.52 Preparation Example 3 5.12 Preparation Example 4 5.41 Preparation Example 5 5.07 Preparation Example 6 4.91 Preparation Example 7 5.49 Preparation Example 8 5.18 Comparative Manufacturing Example 1 4.67 Comparative Manufacturing Example 2 7.39

[0240] It was confirmed that the anode prepared using the dispersion of Comparative Example 1, which had the lowest viscosity, had a very low bonding force between the current collector and the coating layer of the anode slurry composition.

[0242] In Evaluation Examples 1 and 2, when a dispersion (Comparative Preparation Example 2) was used in which the monomer that increases the binding strength of the electrode, such as methyl acrylate, exceeded the content range of the present invention, it was confirmed that the binding strength of the anode was excellent, but the dispersibility was reduced because the viscosity and particle size of the dispersion were excessively high. In addition, when a dispersion (Comparative Preparation Example 1) was used in which the monomer that increases the binding strength of the electrode, such as methyl acrylate, fell below the content range of the present invention, it was confirmed that although the dispersibility was excellent due to the low viscosity and particle size, the binding strength of the anode was reduced.

[0243] That is, only dispersions (Preparation Examples 1 to 4) satisfying the copolymer monomer composition and content of the present invention were able to satisfy the desired level of viscosity and particle size, while also satisfying the desired level of anode bonding strength.

[0245] The scope of the present invention is defined by the claims set forth below rather than by the detailed description above, and all modifications or variations derived from the meaning and scope of the claims and equivalent concepts thereof should be interpreted as being included within the scope of the present invention.

Claims

Claim 1 A copolymer; a solvent; and carbon nanotubes, wherein the copolymer comprises one or more monomer units selected from the group consisting of acrylate-based monomer units comprising one or more substituted or unsubstituted aromatic or aliphatic rings and vinyl-based monomer units comprising one or more substituted or unsubstituted aromatic or aliphatic rings; acrylate-based monomer units comprising linear or branched aliphatic hydrocarbons having 5 to 22 carbon atoms and cyano(CN), pyrrolidone (NC4H6O), carboxylic acid (COOH), amide, alkyl amide, dialkyl amide, alcohol, epoxy group, caprolactam (C5H 10 A dispersion comprising: one or more monomer units selected from the group consisting of polar monomer units comprising at least one selected from the group consisting of CNO), morpholine (C4H8NO), and oxazolidone (C3H4NO2); and one or more monomer units selected from the group consisting of acrylate-based monomer units comprising linear or branched aliphatic hydrocarbons having 1 to 4 carbon atoms and vinyl acetate-based monomer units; wherein, based on 100 mol% of the copolymer, 5 mol% or more and 40 mol% or less of the acrylate-based monomer units comprising linear or branched aliphatic hydrocarbons having 1 to 4 carbon atoms and one or more monomer units selected from the group consisting of vinyl acetate-based monomer units; Claim 2 In claim 1, any one or more monomer units selected from the group consisting of acrylate-series monomer units comprising one or more substituted or unsubstituted aromatic or aliphatic rings and vinyl-series monomer units comprising one or more substituted or unsubstituted aromatic or aliphatic rings are styrene, cyclopentyl acrylate, cyclohexyl acrylate, benzyl acrylate, 3-phenoxybenzyl acrylate, σ-phenylphenoxyethyl acrylate, σ-phenylphenoxyethyl methacrylate, (1-pyrene) 2-methyl-2-propenoate, and 1-naphthyl A dispersion formed by polymerizing acrylate (1-naphthyl acrylate), 1-naphthyl methacrylate, 2-naphthyl acrylate, 2-naphthyl methacrylate, 9-anthracene methyl acrylate, 9-anthracene methyl methacrylate, or a combination thereof. Claim 3 In claim 1, the acrylate-series monomer unit comprising a linear or branched aliphatic hydrocarbon having 5 to 22 carbon atoms is n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-nonyl (meth)acrylate, n-decyl (meth)acrylate, n-undecyl (meth)acrylate, or lauryl (meth)acrylate. (meth)acrylate), n-dodecyl (meth)acrylate, n-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, n-pentadecyl (meth)acrylate, cetyl (meth)acrylate, n-hexadecyl (meth)acrylate, n-heptadecyl (meth)acrylate, stearyl (meth)acrylate, n-nonadecyl (meth)acrylate, n-neicosyl (meth)acrylate, n-heneicosyl (meth)acrylate, n-dococyl (meth)acrylate, iso-pentyl (meth)acrylate,iso-heptyl (meth)acrylate, iso-octyl (meth)acrylate, iso-nonyl (meth)acrylate, iso-decyl (meth)acrylate, iso-undecyl (meth)acrylate, iso-dodecyl (meth)acrylate, iso-tridecyl (meth)acrylate, iso-tetradecyl (meth)acrylate, iso-pentadecyl (meth)acrylate A dispersion formed by polymerizing iso-cetyl (meth)acrylate, iso-hexadecyl (meth)acrylate, iso-heptadecyl (meth)acrylate, iso-stearyl (meth)acrylate, iso-nonadecyl (meth)acrylate, iso-eicosyl (meth)acrylate, iso-heneicosyl (meth)acrylate, iso-docosyl (meth)acrylate, or a combination thereof. Claim 4 In claim 1, the above cyano(CN), pyrrolidone (NC4H6O), carboxylic acid (COOH), amide, alkyl amide, dialkyl amide, alcohol, epoxy group, caprolactam (C5H 10 A dispersion formed by polymerizing a polar monomer unit comprising one or more selected from the group consisting of CNO), morpholine (C4H8NO), and oxazolidone (C3H4NO2), acrylamide, N-methyl acylamide, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate, or a combination thereof. Claim 5 A dispersion according to claim 1, wherein the acrylate series monomer unit comprising a linear or branched aliphatic hydrocarbon having 1 to 4 carbon atoms is formed by polymerizing methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, or a combination thereof, and the vinyl acetate series monomer unit is formed by polymerizing vinyl acetate. Claim 6 In claim 1, based on 100 mol% of the copolymer, one or more monomer units selected from the group consisting of acrylate-based monomer units comprising one or more substituted or unsubstituted aromatic or aliphatic rings in an amount of 1 mol% or more and 60 mol% or less, and vinyl-based monomer units comprising one or more substituted or unsubstituted aromatic or aliphatic rings; and acrylate-based monomer units comprising linear or branched aliphatic hydrocarbons having 5 to 22 carbon atoms in an amount of 5 mol% or more and 80 mol% or less, and cyano(CN), pyrrolidone (NC4H6O), carboxylic acid (COOH), amide, alkyl amide, dialkyl amide, alcohol, epoxy group, caprolactam (C5H 10 A dispersion comprising one or more monomer units selected from the group consisting of polar monomer units including one or more selected from the group consisting of CNO), morpholine (C4H8NO), and oxazolidone (C3H4NO2). Claim 7 In claim 1, the copolymer is a dispersion represented by the following chemical formula 1. [Chemical Formula 1] R1 to R 18 are the same or different from each other and are each independently hydrogen, a linear or branched hydrocarbon having 1 to 4 carbon atoms, R1' is a linear or branched aliphatic hydrocarbon having 5 to 22 carbon atoms, R2' comprises one or more substituted or unsubstituted aromatic or aliphatic rings, R3' comprises one or more substituted or unsubstituted aromatic or aliphatic rings, and R4' is cyano(CN), pyrrolidone (NC4H6O), carboxylic acid (COOH), amide, alkyl amide, dialkyl amide, alcohol, epoxy group, caprolactam (C5H 10 One or more selected from the group consisting of CNO), morpholine (C4H8NO), and oxazolidone (C3H4NO2), R5' and R6' are each independently linear or branched aliphatic hydrocarbons having 1 to 4 carbon atoms, l+m+n+o+p+q=1, and 0.05≤l+o≤0.80, 0.01≤m+n≤0.60, and 0.05≤p+q≤0.

40. (provided that either m or n may be 0, either p or q may be 0, and o may be 0.) Claim 8 In paragraph 7, R1' is n-pentyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, n-undecyl, lauryl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, cetyl, n-hexadecyl, n-heptadecyl, stearyl, n-octadecyl, n-nonadecyl, n-icosyl, n-henicosyl, n-docosyl, iso-pentyl, iso-heptyl, iso-octyl, iso-nonyl, iso-decyl, iso-undecyl, iso-dodecyl, iso-tridecyl, iso-tetradecyl, iso-pentadecyl, iso-cetyl, iso-hexadecyl, iso-heptadecyl, iso-stearyl, iso-octadecyl, A dispersion comprising one or more selected from the group consisting of iso-nonadecil, iso-icosil, iso-henicosil, and iso-docosil. Claim 9 A dispersion in which R2' and R3' are the same or different from each other and each comprises one or more selected from the group consisting of cyclopentyl, cyclohexyl, benzyl, phenyl, phenoxy, naphthalene, anthracene, and pyrene, which are independently substituted or unsubstituted. Claim 10 In claim 7, the monomer comprising R2' is cyclopentyl acrylate, cyclohexyl acrylate, benzyl acrylate, 3-phenoxybenzyl acrylate, σ-phenylphenoxyethyl acrylate, σ-phenylphenoxyethyl methacrylate, (1-pyrene) 2-methyl-2-propenoate, 1-naphthyl acrylate, 1-naphthyl methacrylate, 2-naphthyl acrylate, 2-naphthyl acrylate, 2-naphthyl A dispersion comprising one or more selected from the group consisting of methacrylate (2-naphthyl methacrylate), 9-anthracene methyl acrylate, and 9-anthracene methyl methacrylate, wherein the monomer containing R3' is styrene. Claim 11 A dispersion according to claim 7, wherein the monomer containing R4' is one or more selected from the group consisting of acrylonitrile, vinyl pyrrolidone, acrylic acid, methacrylic acid, itaconic acid, acrylamide, N-methyl acylamide, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, and glycidyl methacrylate. Claim 12 A dispersion according to claim 7, wherein the monomer comprising R5' is one or more selected from the group consisting of methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, and butyl methacrylate, and the monomer comprising R6' is vinyl acetate. Claim 13 The dispersion according to claim 1, wherein the solvent is one or more selected from the group consisting of N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone (NEP), dimethylformamide (DMF), dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), γ-butyrolactone, ethyl acetate, propyl acetate, ethanol, isopropyl alcohol, and deionized water. Claim 14 In claim 1, the copolymer is a dispersion that is a random or block copolymer. Claim 15 In claim 1, a dispersion having a number average molecular weight of the copolymer of 8,000 or more and 40,000 or less. Claim 16 In claim 1, the carbon nanotube is a dispersion in which the carbon nanotube is a single-walled carbon nanotube, a double-walled carbon nanotube, a multi-walled carbon nanotube, or a combination thereof. Claim 17 A dispersion according to claim 1, having a viscosity of 7000 cps or less at a shear rate of 2.5 / s. Claim 18 In claim 1, the dispersion in which the particle size (D50) of the carbon nanotubes dispersed in the dispersion is 18 μm or less. Claim 19 An anode slurry composition comprising: a dispersion of any one of claims 1 to 18; and an anode active material. Claim 20 A positive electrode comprising: a current collector; and a positive electrode active material layer formed by applying the positive electrode slurry composition of claim 19 onto the current collector. Claim 21 In claim 20, the anode slurry composition comprises at least 5 parts by weight and no more than 10 parts by weight of the dispersion based on 100 parts by weight of the total weight of the anode slurry composition, and the anode has a binding force between the current collector and the anode active material layer of 4.7 gf / mm or more. Claim 22 A secondary battery comprising the positive electrode of Article 20.

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