Conductive material dispersion, electrode, and lithium secondary battery

Abstract

The present invention relates to: a conductive material dispersion comprising single-walled carbon nanotube (SWCNT) clusters, wherein the number average length of the SWCNT clusters is 0.8 ㎛ to 8.0 ㎛, the number of the SWCNT clusters having a length exceeding 10 ㎛ is no more than 15% of the total number of SWCNT clusters, the number average diameter of the SWCNT clusters is 5 nm to 30 nm, the number of the SWCNT clusters having a diameter exceeding 30 nm is no more than 15% of the total number of the SWCNT clusters, and the length and diameter of the SWCNT clusters are measured using atomic force microscopy (AFM); and an electrode comprising the SWCNT clusters. The present invention has the advantages of forming a conductive network well due to having excellent dispersibility, and thus being able to achieve excellent conductivity even in small amounts, having excellent processability due to the low viscosity of the dispersion, and being able to contribute to improved battery performance when the conductive material dispersion is applied to the electrode.

Description

Conductive dispersion, electrode, and lithium secondary battery The present invention relates to a conductive dispersion comprising SWCNT clusters having limited length and diameter characteristics, and to an electrode and a lithium secondary battery to which the dispersion is applied. Due to the rapid increase in fossil fuel use, the demand for alternative or clean energy is increasing, and as part of this, the most actively researched field is power generation and storage using electrochemical reactions. Secondary batteries are a prime example of electrochemical devices that utilize this electrochemical energy, and their applications are expanding. With the recent technological development and increasing demand for portable devices such as laptops, mobile phones, and cameras, the demand for secondary batteries as an energy source has rapidly increased. Among these secondary batteries, lithium secondary batteries, which boast high energy density and high capacity, have been extensively studied and are now commercialized and widely used. Secondary battery electrodes include electrode active materials, conductive materials, and binders. Carbon nanotubes can be used as conductive materials to improve electrode conductivity. Especially when using materials with a large surface area, even small amounts can significantly improve conductivity. When single-walled carbon nanotubes (SWCNTs) are used as carbon nanotubes, the resistance of the electrode can be further reduced, and since the specific surface area is relatively large, conductivity can be easily secured with only a small amount. In order for the single-walled carbon nanotubes to be uniformly distributed within the electrode, a conductive dispersion liquid in which the single-walled carbon nanotubes are dispersed is first formed during the manufacture of the electrode, and then an electrode slurry is manufactured using the conductive dispersion liquid. However, single-walled carbon nanotubes have a problem in that the improvement in battery performance varies significantly depending on their dispersibility and unique properties, and there is also a problem in that the expected dispersibility from the values ​​measured in the conductive dispersion is not directly related to the degree of distribution within the electrode, resulting in a discrepancy in the evaluation. Accordingly, when applying single-walled carbon nanotubes as a conductive material for electrodes, research is needed on a conductive material dispersion that has excellent characteristics in a dispersion state and whose characteristics are directly reflected in the electrode, allowing for intuitive prediction of electrode performance through dispersion evaluation. One object of the present invention is to provide a conductive dispersion having excellent dispersibility and low viscosity and excellent processability by applying a single-walled carbon nanotube (SWCNT) cluster, which is an aggregate of single-walled carbon nanotubes having a relatively short length and a small diameter, while minimizing the proportion of SWCNT clusters having a long length and a large diameter, and applying SWCNT clusters having the characteristics of a wide distribution of number-average length distribution and number-average diameter distribution among SWCNT clusters having a relatively short length and a small diameter. Another object of the present invention is to provide an electrode having excellent resistance characteristics by forming a conductive network when the conductive dispersion is applied to an electrode. Another object of the present invention is to provide a lithium secondary battery having excellent output and improved lifespan due to low resistance by including an electrode having excellent conductivity and maintenance performance. [1] According to one embodiment of the present invention, a conductive dispersion is provided, which comprises a single-walled carbon nanotube (SWCNT) cluster, wherein the SWCNT cluster has a number average length of 0.8 µm to 8.0 µm, and the number of SWCNT clusters having a length exceeding 10 µm is 15% or less with respect to the total number, the number average diameter is 5 nm to 25 nm, and the number of SWCNT clusters having a diameter exceeding 30 nm is 15% or less with respect to the total number, and the length and diameter of the SWCNT cluster are measured using an atomic force microscope (AFM). [2] In the above [1], the SWCNT cluster may have an average length of 1.0 μm to 6.0 μm. [3] In the above [1] and / or [2], the SWCNT cluster may be a single-walled carbon nanotube having an average length exceeding 10 μm in a number of 10% or less with respect to the total number. [4] In at least one of the above [1] to [3], the SWCNT cluster may have an average diameter of 7 nm to 20 nm. [5] In at least one of the above [1] to [4], the SWCNT cluster may have a diameter exceeding 30 nm in an amount of 10% or less of the total number of SWCNT clusters. [6] In at least one of the above [1] to [5], the conductive dispersion further includes a dispersant, and the dispersant may include at least one selected from the group consisting of polyacrylate, polyvinylidene fluoride (PVDF), polyvinylpyrrolidone (PVP), polyvinyl alcohol, polyacrylamide, polyethyleneoxide, carboxymethyl cellulose (CMC), and diisopropylamine (DIPA). [7] In the above [6], the conductive dispersion may include 0.2 to 3.5 parts by weight of SWCNT clusters and 0.2 to 7.0 parts by weight of dispersant, relative to 100 parts by weight of the conductive dispersion. [8] According to another embodiment of the present invention, an electrode is provided, wherein an electrode active material layer including an electrode active material, a single-walled carbon nanotube (SWCNT) cluster, and a binder is disposed on a current collector, wherein the SWCNT cluster has a number average length of 0.8 µm to 8.0 µm, and SWCNT clusters having a length exceeding 10 µm account for 15% or less of the total number of SWCNT clusters, and a number average diameter of 5 nm to 30 nm, and SWCNT clusters having a diameter exceeding 30 nm account for 15% or less of the total number of SWCNT clusters, and the length and diameter of the SWCNT clusters are measured using an atomic force microscope (AFM). [9] In the above [8], the electrode active material is a positive electrode active material, and the positive electrode active material may include at least one selected from the group consisting of lithium nickel-ternary oxide, lithium manganese oxide, lithium iron phosphate, lithium nickel oxide, lithium cobalt oxide, and lithium manganese oxide.

[0010] In the above [8] and / or [9], the electrode active material is a negative electrode active material, and the negative electrode active material may include at least one selected from the group consisting of carbon particles, silicon particles, and carbon-silicon composite particles.

[0011] In at least one of the above [8] to

[0010] , the electrode may further include a point-shaped conductive material, and the point-shaped conductive material may include carbon black.

[0012] According to another embodiment of the present invention, a lithium secondary battery is provided having a structure in which a positive electrode, a separator, and a negative electrode are sequentially laminated, and at least one of the positive electrode and the negative electrode is the aforementioned electrode. The conductive dispersion according to the present invention includes SWCNT clusters having unique length and diameter characteristics, thereby having excellent dispersibility and low viscosity, and having little change in viscosity over time, thereby having excellent storage stability and improving processability. Accordingly, by applying the SWCNT clusters having the above characteristics to the electrode slurry, they can contribute to the phase stability of the slurry, and since they have excellent dispersibility, they can sufficiently secure conductivity even in small amounts, thereby realizing electrodes with excellent resistance characteristics. In addition, by applying the electrodes with excellent resistance characteristics as described above, the output of lithium secondary batteries can be improved, and not only is the conductive network well formed, but the retention power is also excellent, which can contribute to the extension of the lifespan of lithium secondary batteries. Terms or words used in this specification and the scope of the claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way. In this specification, the terms “comprise,” “include,” or “have” are intended to specify the presence of a feature, number, step, component, or combination thereof, but do not exclude the presence or addition of one or more other features, numbers, steps, components, or combinations thereof. In this specification, the volume cumulative average particle diameter D 50 and D 90 In the particle size distribution curve of silver particles, the particle sizes corresponding to 50% and 90% of the volume accumulation can be defined, respectively. The above D 50 and D 90 For example, it can be measured using the laser diffraction method. The laser diffraction method can generally measure particle diameters from the submicron range to several mm, and can obtain results with high reproducibility and high resolution. In this specification, the number average length and diameter of carbon nanotubes and the ratio of lengths exceeding 10 ㎛ and diameters exceeding 30 nm can be derived by obtaining the length and diameter of 400 or more carbon nanotubes through images measured at a magnification of 20 ㎛ x 20 ㎛, 15 ㎛ x 15 and / or 10 ㎛ x 10 ㎛ using an atomic force microscope (AFM) (Asylum Research, Cypher ES AFM System) in AC Air Topography mode (Tapping mode) under the conditions of a set point of 0.4 V and a scan rate of 1.5 Hz, and obtaining the number cumulative length and diameter distribution. In this specification, a cluster may mean a form in which multiple units are combined to form a single aggregate, and a single-wall carbon nanotube (SWCNT) cluster may mean an aggregate or collection in which multiple SWCNT units are combined to form a single fiber. Hereinafter, the present invention will be described in detail. In this specification, each of the conductive dispersion, electrode, and lithium secondary battery includes at least one of the technical features and / or technical configurations described below, and these technical features and / or technical configurations can be combined in various ways. Dispersion of challenge agent A conductive dispersion according to one embodiment of the present invention comprises a single-walled carbon nanotube (SWCNT) cluster, wherein the SWCNT cluster has a number average length of 0.8 μm to 8.0 μm, and the number of SWCNT clusters having a length exceeding 10 μm is 15% or less with respect to the total number, the number average diameter is 5 nm to 25 nm, and the number of SWCNT clusters having a diameter exceeding 30 nm is 15% or less with respect to the total number, and the length and diameter of the SWCNT cluster are measured using an atomic force microscope (AFM). (1) Single-walled carbon nanotubes Carbon nanotubes are graphite sheets that have a cylindrical shape with a nano-sized diameter and an sp2 bonding structure. Depending on the angle and structure at which the graphite sheets are rolled, they exhibit the properties of conductors or semiconductors. Carbon nanotubes can be classified into single-walled carbon nanotubes (SWCNTs), double-walled carbon nanotubes (DWCNTs), and multi-walled carbon nanotubes (MWCNTs) depending on the number of bonds forming the wall. According to one embodiment of the present invention, the conductive dispersion comprises a SWCNT cluster, which is an aggregate of single-walled carbon nanotubes (SWCNTs). Since single-walled carbon nanotubes have a larger specific surface area than multi-walled carbon nanotubes, even if only a small amount is added, sufficient conductivity can be secured, thereby significantly increasing the reduction in electrode resistance. However, in the case of single-walled carbon nanotubes, in order to maximize the advantage of easily securing conductivity even with a small amount, the length characteristic must be excellent. However, the length characteristic is not easy to accurately measure, and the expected degree of improvement in conductivity is often not directly reflected. Furthermore, even if the length characteristic is good, there is a problem that if it is excessive, it can affect the viscosity of the dispersion and, further, the viscosity of the slurry. Accordingly, the inventors of the present invention seek to provide a conductive dispersion containing SWCNT clusters with limited length and diameter characteristics and unique characteristics, which can intuitively predict the ability to form a conductive path within an electrode through these measurements, while ensuring excellent dispersibility without increasing the viscosity of the dispersion. The SWCNT clusters included in the conductive dispersion according to one embodiment of the present invention are characterized in that they have a number average length of 0.8 µm to 8.0 µm, and SWCNT clusters exceeding 10 µm in length account for 15% or less of the total number, and the number average length of the SWCNT clusters and the number ratio of SWCNT clusters exceeding 10 µm in length can be derived through a number distribution obtained through the aforementioned atomic force microscope measurement. The above SWCNT cluster is characterized in that it has an appropriate length satisfying the number average length of 0.8 ㎛ to 8.0 ㎛, and excludes SWCNT clusters having a long length exceeding 10 ㎛, and additionally, it may be characterized in that the formed conductive network can be well maintained even when the volume of the electrode expands during the charge / discharge cycle process within the range satisfying the number average length. According to one embodiment of the present invention, the SWCNT cluster has a number average length of 0.8 μm to 8.0 μm, preferably 0.9 μm or more, 1.0 μm or more, 1.1 μm or more, 1.2 μm or more, 1.3 μm or more, 1.4 μm or more, or 1.5 μm or more, and may be 7.8 μm or less, 7.5 μm or less, 7.0 μm or less, 6.5 μm or less, 6.0 μm or less, 5.5 μm or less, 5.0 μm or less, 4.5 μm or less, or 4.0 μm or less. When the number average length is less than 0.8 μm, the length is too short, and it may not be easy to maintain a conductive network connection path due to a volume change of the electrode due to charge and discharge. In addition, when the average particle length exceeds 8.0 μm, the number of SWCNT clusters per unit weight decreases, while the viscosity of the dispersion increases and the distribution within the electrode becomes uneven, which may cause problems. In addition, according to one embodiment of the present invention, the SWCNT clusters are characterized in that the SWCNT clusters having a length exceeding 10 μm account for 15% or less of the total number of SWCNT clusters, and preferably 13% or less, 11% or less, 10% or less, or 9% or less. When the number of SWCNT clusters exceeding 10 μm exceeds 15%, the viscosity of the dispersion cannot be controlled, and even if the dispersion conditions are adjusted to achieve uniform dispersion, the possibility that the viscosity will change significantly over time may increase rapidly. In addition, as the number of long SWCNT clusters increases, it becomes more difficult to achieve a uniform distribution within the electrode, and it is highly likely that the expectation for securing conductivity measured on the dispersion will not be intuitively reflected in the electrode state. Therefore, the number of SWCNT clusters exceeding 10 μm needs to be precisely controlled. The SWCNT clusters included in the conductive dispersion according to one embodiment of the present invention are characterized in that they have a number average diameter of 7 nm to 20 nm, and SWCNT clusters having a diameter exceeding 30 nm account for 10% or less of the total number, and the number average diameter of the SWCNT clusters and the number ratio of SWCNT clusters having a diameter exceeding 30 nm can be derived through a number distribution obtained through the aforementioned atomic force microscope measurement. The above SWCNT cluster is characterized in that it has an appropriate diameter satisfying a number average diameter of 7 nm to 20 nm, and that an excessive amount of SWCNT clusters having a thick diameter exceeding 30 nm is excluded, and additionally, it may be characterized in that the formed conductive network can be well maintained even when the volume of the electrode expands during a charge / discharge cycle within the range satisfying the number average diameter. According to one embodiment of the present invention, the SWCNT cluster has a number average diameter of 7 nm to 20 nm, and preferably, 8 nm or more, 9 nm or more, 10 nm or more, 11 nm or more, or 12 μm or more, and 19 nm or less, 18 nm or less, 17 nm or less, 16 nm or less, or 15 nm or less. When the number average diameter is less than 7 nm, the SWCNT cluster may be easily damaged during charge and discharge due to the diameter being too thin, and problems such as disconnection due to volume expansion may occur, making it difficult to maintain a conductive network connection path. In addition, when the number average diameter exceeds 20 nm, the number of SWCNT clusters per unit weight may decrease, while the viscosity of the dispersion may increase, and the dispersion may not be appropriate, resulting in a problem that the distribution within the electrode may not be uniform, and when attached to the surface of the active material, it may act as a factor that hinders the mobility of lithium ions. According to one embodiment of the present invention, the SWCNT cluster is characterized in that the SWCNT clusters having a length exceeding 30 nm account for 10% or less of the total number of SWCNT clusters, and preferably 9% or less, 8% or less, or 7% or less. When the number of SWCNT clusters exceeding 30 nm in diameter exceeds 10%, the viscosity of the dispersion cannot be controlled, and even if the dispersion conditions are adjusted to achieve uniform dispersion, the possibility that the viscosity will change significantly over time may increase rapidly. In addition, as the number of SWCNT clusters having a large diameter increases, it becomes more difficult to achieve a uniform distribution within the electrode, and as described above, it is highly likely that the SWCNT clusters will act as a factor that hinders the mobility of lithium ions. Therefore, the number of SWCNT clusters exceeding 30 nm in diameter needs to be precisely controlled. Typically, in the case of a conductive dispersion containing carbon nanotubes, the volume cumulative average particle diameter (D) of the dispersion is used to predict the formation of a conductive path and uniform distribution at the electrode. 50 and / or D 90 ) is often utilized, but the particle size distribution in the dispersed state does not accurately reflect the length and diameter of actual carbon nanotubes or their aggregates, so that even when the same particle size distribution is applied, there are cases where the performance of the electrode appears differently. However, the length and diameter characteristics obtained from the number cumulative length and diameter distribution through an atomic force microscope image according to one embodiment of the present invention are more effective and intuitive in improving the performance of the electrode because the degree of conductive network formation in the dispersed state and within the electrode appears substantially the same. According to one embodiment of the present invention, the SWCNT cluster may be included in an amount of 0.2 to 3.5 parts by weight, and specifically, 0.2 to 3.0 parts by weight, based on 100 parts by weight of the conductive material dispersion. When the above range is satisfied, high productivity is maintained while the electrode slurry can be easily transported and injected. In addition, since the solid content of the electrode slurry being manufactured is not excessively low, binder migration can be suppressed during electrode drying. Accordingly, electrode adhesion can be improved, and the packing of the electrode active material layer can be effectively performed, so that an electrode with a low thickness can be manufactured. (2) Dispersant The conductive dispersion according to one embodiment of the present invention may further include a dispersant, and the dispersant may include at least one selected from the group consisting of polyacrylate, polyvinylidene fluoride (PVDF), polyvinylpyrrolidone (PVP), polyvinyl alcohol, polyacrylamide, polyethyleneoxide, hydrogenated nitrile copolymers, cellulose compounds, and diisopropylamine (DIPA). Here, the hydrogenated nitrile copolymer may be hydrogenated acrylonitrile-butadiene rubber, and the cellulose compound may be carboxymethyl cellulose (CMC) or hydroxyethyl cellulose (HEC). In addition, the dispersant in the conductive material dispersion may be included in an amount of 0.2 to 7.0 parts by weight, specifically 0.2 to 6.0 parts by weight, and more specifically 0.3 to 5.0 parts by weight, based on 100 parts by weight of the conductive material dispersion. When the above range is satisfied, the carbon-based conductive material can be smoothly dispersed in the conductive material dispersion, and the energy density of the electrode being manufactured can be improved and the resistance can be reduced. (3) Solvent According to one embodiment of the present invention, the conductive dispersion may further include a solvent, and the solvent may include water or an organic solvent, and the organic solvent may include one or more heteroatoms selected from the group consisting of nitrogen atoms (N) and oxygen atoms (O) having unshared electron pairs. Specifically, the organic solvent may be an amide-based polar organic solvent such as dimethylformamide (DMF), diethyl formamide, dimethyl acetamide (DMAc), or N-methyl pyrrolidone (NMP); an alcohol such as methanol, ethanol, 1-propanol, 2-propanol (isopropyl alcohol), 1-butanol (n-butanol), 2-methyl-1-propanol (isobutanol), 2-butanol (sec-butanol), 1-methyl-2-propanol (tert-butanol), pentanol, hexanol, heptanol, or octanol; a glycol such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,5-pentanediol, or hexylene glycol; Examples thereof include polyhydric alcohols such as glycerin, trimethylolpropane, pentaerythritol, or sorbitol; glycol ethers such as ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, tetraethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, triethylene glycol monoethyl ether, tetraethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, or tetraethylene glycol monobutyl ether; ketones such as acetone, methyl ethyl ketone, methyl propyl ketone, or cyclopentanone; and esters such as ethyl acetate, γ-butyl lactone, and ε-propiolactone, and any one of these or a mixture of two or more thereof may be used. Considering compatibility with electrode slurry, N-methyl pyrrolidone (NMP) is particularly preferred. (4) Other According to one embodiment of the present invention, in the conductive dispersion, the solid content of the conductive dispersion may be 0.3 wt% to 7.0 wt%, specifically 0.4 wt% to 5.0 wt%, and more specifically 0.5 wt% to 3.5 wt%. When the above range is satisfied, the viscosity of the conductive dispersion can be maintained at a low level, while the conductive dispersion can be effectively dispersed. Here, the solid content may refer to the SWCNT cluster and dispersant included in the conductive dispersion. The conductive dispersion of the present invention including the above components can be prepared by mixing SWCNT clusters, a dispersant, and a solvent. At this time, the mixing can be performed using a conventional mixing method, specifically, a mixing device such as a homogenizer, a bead mill, a ball mill, a basket mill, an attrition mill, a universal stirrer, a clear mixer, a spike mill, or a TK mixer, and the order of mixing each component is not particularly limited. That is, the conductive dispersion according to the present invention can be prepared by a method of adding single-walled carbon nanotubes (e.g., in the form of micro-sized large bundles) to a solvent and then adding a dispersant and mixing, or by a method of first adding a dispersant to a solvent and then mixing the single-walled carbon nanotube bundles, or by a method of adding single-walled carbon nanotube bundles and a dispersant together to a solvent and then mixing. Meanwhile, cavitation dispersion treatment may be performed during the above mixing process to enhance the dispersibility of single-walled carbon nanotube bundles. The cavitation dispersion treatment is a dispersion treatment method that utilizes shock waves generated by the bursting of vacuum bubbles formed in water when high energy is applied to the liquid. Through the method, single-walled carbon nanotubes can be dispersed into SWCNT clusters without damaging their properties. Specifically, the cavitation dispersion treatment may be performed by ultrasonic waves, a jet mill, or shear dispersion treatment. According to one embodiment of the present invention, the conductive material dispersion may further include a dot-shaped conductive material. The conductive material that may be additionally included has different characteristics from the SWCNT clusters having the aforementioned characteristics, and it may be preferable that the shape characteristics be different. When a conductive material with similar shape characteristics, such as a linear conductive material such as a multi-walled carbon nanotube or carbon nanofiber, is included, it may affect the formation of a conductive network due to the characteristics of the SWCNT clusters described above. For example, the dot-shaped conductive material may include carbon black, and the carbon black may include at least one selected from the group consisting of acetylene black, Ketjen black, channel black, furnace black, lamp black, and thermal black. electrode According to another embodiment of the present invention, an electrode is provided, wherein an electrode active material layer including an electrode active material, a single-walled carbon nanotube (SWCNT) cluster, and a binder is disposed on a current collector, wherein the SWCNT cluster has a number average length of 0.8 µm to 8.0 µm, and SWCNT clusters having a length exceeding 10 µm account for 15% or less of the total number of SWCNT clusters, and a number average diameter of 5 nm to 30 nm, and SWCNT clusters having a diameter exceeding 30 nm account for 15% or less of the total number of SWCNT clusters, and the length and diameter of the SWCNT clusters are measured using an atomic force microscope (AFM). At this time, the SWCNT cluster is a SWCNT cluster included in the conductive dispersion according to the present invention described above, and since the details thereof are the same as those described above, a detailed description thereof will be omitted, and the remaining components will be described below. According to one embodiment of the present invention, the electrode active material may be a positive electrode active material, the electrode may be a positive electrode, and the positive electrode may include a positive electrode current collector and a positive electrode active material layer formed on the positive electrode current collector and including the positive electrode active material. In the above positive electrode, the positive electrode current collector may be any conductive material that does not cause chemical changes in the battery, and is not particularly limited. For example, the positive electrode current collector may be made of stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel surface-treated with carbon, nickel, titanium, silver, or the like. The above-described positive electrode current collector may typically have a thickness of 3 μm to 500 μm, and preferably may have a thickness of 300 μm or less, 200 μm or less, 100 μm or less, or 80 μm or less. Fine unevenness may be formed on the surface of the positive electrode current collector to strengthen the bonding strength with the positive electrode active material. For example, it may be used in various forms such as a film, sheet, foil, net, porous body, foam, or non-woven fabric. The above positive electrode active material may be a commonly used positive electrode active material. Specifically, the positive electrode active material may be a layered compound such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), or a compound substituted with one or more transition metals; lithium iron oxide such as LiFe3O4; or a compound having the chemical formula Li 1+c1 Mn 2-c1 Lithium manganese oxides such as O4(0≤c1≤0.33), LiMnO3, LiMn2O3, LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O8, V2O5, Cu2V2O7; chemical formula LiNi 1-c2 M c2Ni-site type lithium nickel oxide or lithium nickel-ternary oxide expressed as O2 (wherein, M is at least one selected from the group consisting of Co, Mn, Al, Cu, Fe, Mg, B, and Ga, and satisfies 0.01≤c2≤0.3); chemical formula LiMn 2-c3 M c3 Lithium manganese composite oxide represented by O2 (wherein, M is at least one selected from the group consisting of Co, Ni, Fe, Cr, Zn, and Ta, and satisfies 0.01≤c3≤0.1) or Li2Mn3MO8 (wherein, M is at least one selected from the group consisting of Fe, Co, Ni, Cu, and Zn); LiMn2O4, etc., in which a part of Li in the chemical formula is replaced with an alkaline earth metal ion, but is not limited thereto. The positive electrode may be Li-metal. Preferably, the positive electrode active material may include at least one selected from the group consisting of lithium nickel-ternary oxide, lithium manganese oxide, lithium iron phosphate, lithium nickel oxide, lithium cobalt oxide, and lithium manganese oxide. The above-described positive electrode active material layer may include a positive electrode conductive material and a positive electrode binder together with the positive electrode active material described above. At this time, the positive electrode conductive material may be applied with the aforementioned conductive material dispersion, and may be additionally included to provide conductivity to the electrode in addition to the conductive material dispersion, and in the battery to be constructed, any material that does not cause a chemical change and has electronic conductivity may be used without any special restrictions. Specific examples include graphite such as natural graphite or artificial graphite; carbon black such as acetylene black, Ketjen black, channel black, furnace black, lamp black, and summer black; fibrous carbon materials such as carbon nanotubes, carbon nanofibers, and carbon fibers; metal powders or metal fibers such as copper, nickel, aluminum, and silver; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; or conductive polymers such as polyphenylene derivatives, and the like. One of these may be used alone or a mixture of two or more may be used. In addition, the positive electrode binder plays a role of improving the adhesion between positive electrode active material particles and the adhesiveness between the positive electrode active material and the positive electrode current collector. Specific examples include polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol, polyacrylonitrile, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl pyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene butadiene rubber (SBR), fluoroelastomer, or various copolymers thereof, and one of these may be used alone or a mixture of two or more thereof. According to one embodiment of the present invention, the electrode active material may be a negative electrode active material, the electrode may be a negative electrode, and the negative electrode may include a negative electrode current collector and a negative electrode active material layer formed on the negative electrode current collector and including the negative electrode active material. The above negative electrode current collector is not particularly limited as long as it has high conductivity without causing chemical changes in the battery, and for example, copper, stainless steel, aluminum, nickel, titanium, heat-treated carbon, copper or stainless steel surface-treated with carbon, nickel, titanium, silver, etc., aluminum-cadmium alloy, etc. can be used. The negative electrode current collector may typically have a thickness of 3 μm to 500 μm, and preferably 300 μm or less, 200 μm or less, 100 μm or less, or 80 μm or less. Fine unevenness may be formed on the surface of the negative electrode current collector to strengthen the bonding strength with the negative electrode active material. For example, it may be used in various forms such as a film, sheet, foil, net, porous body, foam, or non-woven fabric. As the negative electrode active material, a compound capable of reversible intercalation and deintercalation of lithium can be used. Specific examples include carbonaceous materials such as artificial graphite, natural graphite, graphitized carbon fiber, and amorphous carbon; (semi-)metallic compounds capable of alloying with lithium, such as Si, Al, Sn, Pb, Zn, Bi, In, Mg, Ga, Cd, Si alloy, Sn alloy, or Al alloy; SiOv(0 <v≤2), SnO2, 바나듐 산화물, 리튬 바나듐 산화물과 같이 리튬을 도프 및 탈도프할 수 있는 (준)금속 산화물; 또는 Si-C 복합체 또는 Sn-C 복합체과 같이 상기 금속질 화합물과 탄소질 재료를 포함하는 복합물 등을 들 수 있으며, 이들 중 어느 하나 또는 둘 이상의 혼합물이 사용될 수 있다. 또한, 상기 음극활물질로서 금속 리튬 박막이 사용될 수도 있다. 또, 탄소재료는 저결정성 탄소 및 고결정성 탄소 등이 모두 사용될 수 있다. 저결정성 탄소로는 연화탄소 (soft carbon) 및 경화탄소 (hard carbon)가 대표적이며, 고결정성 탄소로는 무정형, 판상, 인편상, 구형 또는 섬유형의 천연 흑연 또는 인조 흑연, 키시 흑연 (Kish graphite), 열분해 탄소 (pyrolytic carbon), 액정 피치계 탄소섬유 (mesophase pitch based carbon fiber), 탄소 미소구체 (meso-carbon microbeads), 액정피치 (Mesophase pitches) 및 석유와 석탄계 코크스 (petroleum or coal tar pitch derived cokes) 등의 고온 열처리탄소가 대표적이다. For example, the negative electrode active material may include at least one selected from the group consisting of carbon particles, silicon particles, and carbon-silicon composite particles. Also preferably, the negative electrode active material may include a silicon-based active material, for example, Si particles, SiOv(0 <v≤2), 또는 Si-C 복합체를 포함할 수 있다. The above negative active material may be included in an amount of 70 wt% to 99 wt% based on the total solid content in the negative slurry, may be 75 wt% or more, 80 wt% or more, 85 wt% or more, 90 wt% or more, or 95 wt% or more, and may also be included in an amount of 99.0 wt% or less, 98.5 wt% or less, 98.0 wt% or less, or 97.5 wt% or less. When the content of the negative active material satisfies the above range, excellent energy density, electrode adhesion, and electrical conductivity can be realized. The above binder is intended to secure adhesion between electrode active materials or between electrode active materials and a current collector, and general binders used in the relevant technical field can be used, and the type thereof is not particularly limited. Examples of the binder include polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol, polyacrylonitrile, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl pyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene-butadiene rubber (SBR), fluororubber, or various copolymers thereof, and one type alone or a mixture of two or more types thereof may be used. The above binder may be included in an amount of 10.0 wt% or less based on the total solid content in the negative electrode slurry, preferably 0.5 wt% or more, 1.0 wt% or more, 1.5 wt% or more, or 2.0 wt% or more, and further may be included in an amount of 9.0 wt% or less, 8.0 wt% or less, 7.0 wt% or less, or 5.0 wt% or less. When the binder content satisfies the above range, excellent electrode adhesion can be realized while minimizing an increase in electrode resistance. At this time, the negative electrode conductive material may be applied with the aforementioned conductive material dispersion, and may be additionally included to provide conductivity to the electrode in addition to the conductive material dispersion, and in the battery to be constructed, any material that does not cause a chemical change and has electronic conductivity may be used without special restrictions. Specific examples include graphite such as natural graphite or artificial graphite; carbon black such as acetylene black, Ketjen black, channel black, furnace black, lamp black, and summer black; fibrous carbon materials such as carbon nanotubes, carbon nanofibers, and carbon fibers; metal powders or metal fibers such as copper, nickel, aluminum, and silver; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; or conductive polymers such as polyphenylene derivatives, and the like. One of these may be used alone or a mixture of two or more may be used. Meanwhile, the electrode active material layer can be formed by coating an electrode slurry containing an electrode active material, a binder, and a conductive material dispersion solution including the SWCNT cluster in a solvent on a current collector, and then performing a drying and rolling process. Specifically, the electrode active material layer can be formed by applying electrode slurry onto an electrode current collector and then drying it, or by applying electrode slurry onto a separate support and then peeling the support to obtain a film and laminating it onto an electrode current collector. If necessary, a rolling process can be additionally performed after the electrode active material layer is formed using the above method. At this time, drying and rolling can be performed under appropriate conditions taking into account the physical properties of the electrode to be ultimately manufactured, and are not particularly limited. The above electrode slurry may further include a solvent, if necessary, for viscosity control, etc. At this time, the solvent may be water, an organic solvent, or a mixture thereof. Examples of the organic solvent include amide-based polar organic solvents such as dimethylformamide (DMF), diethyl formamide, dimethyl acetamide (DMAc), N-methyl pyrrolidone (NMP); alcohols such as methanol, ethanol, 1-propanol, 2-propanol (isopropyl alcohol), 1-butanol (n-butanol), 2-methyl-1-propanol (isobutanol), 2-butanol (sec-butanol), 1-methyl-2-propanol (tert-butanol), pentanol, hexanol, heptanol, or octanol; Glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,5-pentanediol, or hexylene glycol; polyhydric alcohols such as glycerin, trimethylolpropane, pentaerythritol, or sorbitol; glycol ethers such as ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, tetraethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, triethylene glycol monoethyl ether, tetraethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, or tetraethylene glycol monobutyl ether; Examples thereof include ketones such as acetone, methyl ethyl ketone, methyl propyl ketone, or cyclopentanone; esters such as ethyl acetate, γ-butyl lactone, and ε-propiolactone; and any one or a mixture of two or more of these may be used, but is not limited thereto. The solvent may be included in an amount such that the solid content in the electrode slurry is 40 wt% to 85 wt%, preferably 50 wt% to 80 wt%. When the above range is satisfied, binder migration can be suppressed, thereby improving electrode adhesion, the drying temperature can be lowered, thereby improving coatability, and the coating speed can be increased, thereby improving productivity. lithium secondary battery According to another embodiment of the present invention, a lithium secondary battery has a structure in which a positive electrode, a separator, and an anode are sequentially laminated, and at least one of the positive electrode and the negative electrode is the electrode described above. Specifically, the lithium secondary battery according to the present invention may include a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and an electrolyte, wherein the positive electrode and the negative electrode are as described above. Below, only the remaining components will be described. According to one embodiment of the present invention, the separator separates the negative electrode and the positive electrode and provides a passage for lithium ions, and can be used without any particular limitation as long as it is commonly used as a separator in a secondary battery. Specifically, the separator may be a porous polymer film, for example, a porous polymer film made of a polyolefin polymer such as ethylene homopolymer, propylene homopolymer, ethylene / butene copolymer, ethylene / hexene copolymer, and ethylene / methacrylate copolymer, or a laminated structure of two or more layers thereof. In addition, a conventional porous nonwoven fabric, for example, a nonwoven fabric made of high-melting-point glass fiber, polyethylene terephthalate fiber, etc. may also be used. In addition, a coated separator containing a ceramic component or a polymer material to secure heat resistance or mechanical strength may be used, and may optionally be used in a single-layer or multi-layer structure. According to one embodiment of the present invention, the electrolyte may include, but is not limited to, an organic liquid electrolyte, an inorganic liquid electrolyte, a solid polymer electrolyte, a gel-type polymer electrolyte, a solid inorganic electrolyte, a molten inorganic electrolyte, etc. that can be used in the manufacture of a lithium secondary battery. Specifically, the electrolyte may include a non-aqueous organic solvent and a metal salt. As the above non-aqueous organic solvent, for example, an aprotic organic solvent such as N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma-butyrolactone, 1,2-dimethoxyethane, tetrahydroxyfuran, 2-methyl tetrahydrofuran, dimethylsulfoxide, 1,3-dioxolan, formamide, dimethylformamide, dioxolan, acetonitrile, nitromethane, methyl formate, methyl acetate, triester phosphate, trimethoxy methane, dioxolan derivatives, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate derivatives, tetrahydrofuran derivatives, ethers, methyl pyrropionate, ethyl propionate, etc. can be used. there is. In particular, among the above carbonate-based organic solvents, ethylene carbonate and propylene carbonate, which are cyclic carbonates, are high-viscosity organic solvents with high dielectric constants and thus can be preferably used because they easily dissociate lithium salts. In addition, when low-viscosity, low-dielectric constant linear carbonates such as dimethyl carbonate and diethyl carbonate are mixed and used in an appropriate ratio with these cyclic carbonates, an electrolyte with high electrical conductivity can be produced, so that they can be used even more preferably. The metal salt may be a lithium salt, and the lithium salt is a substance that is easily dissolved in the non-aqueous electrolyte, for example, the anion of the lithium salt is F - , Cl - , I - , NO3 - , N(CN)2 - , BF4 -, ClO4 - , PF6 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , CF3SO3 - , CF3CF2SO3 - , (CF3SO2)2N - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - and (CF3CF2SO2)2N - One or more selected from the group consisting of may be used. In addition to the electrolyte components, the electrolyte may further include one or more additives, such as, for example, a haloalkylene carbonate compound such as difluoroethylene carbonate, pyridine, triethylphosphite, triethanolamine, a cyclic ether, ethylene diamine, n-glyme, hexaphosphoric acid triamide, nitrobenzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N,N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrrole, 2-methoxyethanol, or aluminum trichloride, for the purpose of improving the life characteristics of the battery, suppressing battery capacity decrease, and improving the discharge capacity of the battery. Example Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement them. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein. Examples 1a to 4a and Comparative Examples 1a to 9a: Conductive dispersions 1 part by weight of single-walled carbon nanotube bundles, 1 part by weight of polyvinylpyrrolidone (PVP, K15, Zhangzhou Huafu Co.) as a dispersant, and 200 parts by weight of N-methyl pyrrolidone were mixed, and then the mixture was mixed for 180 minutes using a mixer (BTM-50, disper 1000 rpm / anchor 100 rpm). The resulting conductive dispersion was mixed for a second time at different mixing ratios (weight ratios) as shown in Table 1 below by varying the number of circulations using a high-pressure homogenizer (NG-20K, Genizer Co.), thereby obtaining dispersions containing SWCNT clusters with a solid content of 1 wt%. Pressure Index*10 pass circulating dispersion5 pass circulating dispersion2 pass circulating dispersionExample 1a10073-Example 2a10064-Example 3a1006.530.5Example 4a130-55Comparative Example 1a17073-Comparative Example 2a1708-2Comparative Example 3a100-28Comparative Example 4a130-37Comparative Example 5a100442Comparative Example 6a100226Comparative Example 7a100127Comparative Example 8a100118Comparative Example 9a17091- * For the pressure applied to each, the pressure of Example 1 is considered as 100, and the value is expressed as a relative value based on this. Experimental Example 1: Length and Particle Size Measurement After diluting the conductive dispersions of the above examples and comparative examples in water, 50 μl of the diluted solution was dropped onto the surface of freshly cleaved mica and then vacuum dried to prepare a sample. The prepared sample was photographed using an atomic force microscope (AFM) (Asylum Research, Cypher ES AFM System) under the following conditions. - Measurement mode: AC Air Topography mode (Tapping mode) - Measurement conditions: Set point 0.4 V, Scan rate 1.5 Hz - Measurement image size: Measured at magnifications of 20 ㎛ x 20 ㎛, 15 ㎛ x 15 and 10 ㎛ x 10 ㎛ - Probe: AC160TS (n-type doped Si, reflective Al coating,f0300 kHz,k26 N / m) The length and diameter of more than 100 SWCNT clusters were measured (using an image processing program) through AFM images obtained by measuring under the above conditions, and a length distribution was obtained. Then, the number average length and diameter, the number ratio of SWCNT clusters exceeding 10 ㎛ in length, and the number ratio of SWCNT clusters exceeding 30 nm in diameter were derived. Volume cumulative average particle diameter D 50 (㎛) and D 90 (㎛) was measured by introducing the above-mentioned conductive dispersion into a laser diffraction particle size measuring device (Mastersizer2000, Malvern) and irradiating it with ultrasonic waves of approximately 28 kHz at an output of 60 W, obtaining a volume-cumulative particle size distribution graph, and then calculating the particle size corresponding to 50% of the volume-cumulative amount. Number of average lengths (㎛)Length exceeding 10 ㎛Number of average diameters (nm)Number of diameters exceeding 30 nmD50 (㎛)D90 (㎛)Example 1a1.541.0933.612.1Example 2a1.721.51043.515.8Example 3a2.303.91763.820.1Example 4a4.207.82193.828.1Comparative example 1a0.680433.415.8Comparative example 2a0.710.2653.515.5Comparative example 3a7.1022.0382128.092.0Comparative example 4a3.007.032103.925.0Comparative example 5a2.006.020153.123.0Comparative example 6a3.007.029133.928.0Comparative example 7a9.008.025108.043.0Comparative example 8a2.0030.0251023.085.0Comparative example 9a0.605.0333.519.0 Referring to Table 2 above, the volume cumulative average particle diameter D in the dispersion phase 50 and D 90 Although the values ​​appear similar, it can be confirmed that the lengths of the SWCNT clusters actually included in the electrode are different. Examples 1b to 4b and Comparative Examples 1b to 9b The average particle diameter (D) of the negative active material 50 ) Pure Si particles having a particle size of 5 μm, particle-type conductive agent (SFG6L), dispersions of each conductive agent (based on solid weight) prepared in Examples 1a to 4a and Comparative Examples 1a to 9a, and an aqueous binder were mixed in a weight ratio of 80:9.6:0.8:9.6, and water was used as a solvent to prepare a negative electrode slurry having a solid content of 30%. Here, the aqueous binder is a polymer obtained by polymerizing acrylamide, acrylic acid, and acrylonitrile in a weight ratio of 60:30:10 (ammonium persulfate polymerization initiator, 75°C, 8 hours polymerization reaction). The above negative electrode slurry was coated on one side of a copper foil having a thickness of 18 μm so that the active material layer had a thickness of 50 μm, and then dried to produce a negative electrode. Experimental Example 2: Evaluation of Coating Processability and Lifetime Characteristics An electrode assembly was manufactured by interposing a porous polyethylene separator between the negative electrode and the positive electrode of Examples 1b to 4b and Comparative Examples 1b to 9b, and then positioning this assembly inside a case, and then injecting an electrolyte solution to manufacture a lithium secondary battery. At this time, the electrolyte was prepared by dissolving 1 M LiPF6 in an organic solvent with a volume ratio of ethylene carbonate / ethyl methyl carbonate / diethyl carbonate of 3:4:4, and the positive electrode was prepared as follows. The above anode is LiNi 0.6 Co 0.1 Mn 0.3O2, polyvinylidene fluoride, and carbon black were added in a weight ratio of 95:3:2, and N-methylpyrrolidone (NMP) was additionally added to prepare a positive electrode slurry having a solid content of 70.1 wt%. The positive electrode slurry was then applied onto a 20 ㎛ thick Al thin film current collector, dried at 130°C, and rolled to prepare a positive electrode slurry. The above lithium secondary battery was charged to 4.2 V at a C-rate of 0.1 C and then discharged to 2.5 V to perform an activation process. The capacity retention rate was measured by performing 100 charge-discharge cycles, in which each lithium secondary battery was charged in CCCV mode at 0.2C until 4.25V (end current 1 / 20C), then charged to 4.25V at 0.33C constant current at 45°C, and discharged to 2.5V at 0.33C constant current, as one cycle, and the charge-discharge capacity was measured, and the capacity retention rate was calculated as follows. Capacity retention rate (%) = (discharge capacity after 100 cycles) / (discharge capacity after 1 cycle) Х100 The coating fairness was evaluated by checking whether there were any stains on the electrode surface, pinholes, or clogging of the filter in the slurry circulation pump when coating the cathode slurry on the copper foil. If any of the problems occurred, it was evaluated as X, and if no problems occurred, it was evaluated as O. Cathode capacity retention rate (%) Electrode coating property Example 1b82O Example 2b85O Example 3b86O Example 4b85O Comparative Example 1b62O Comparative Example 2b68O Comparative Example 3b75X Comparative Example 4b72O Comparative Example 5b70O Comparative Example 6b71O Comparative Example 7b77O Comparative Example 8b72X Comparative Example 9b65O Referring to Table 3 above, it can be confirmed that when the cathodes of Examples 1b to 4b were applied, no problems occurred in the coating process and the capacity retention rate was also at an excellent level. However, when the cathodes of Comparative Examples 1b and 2b were applied, the capacity retention rate was approximately 20% worse than that of the Examples. This can be said to be a difference in performance that cannot be distinguished through the particle size distribution of the conductive agent dispersion. Specifically, the results of Comparative Examples 1b and 2b above indicate that even if the particle size of the dispersion phase is determined to be an appropriate size, the actual length of the SWCNT cluster is too short to form a normal conductive path, and thus, it can be said that these results show that performance can be improved when the conductive dispersion according to the present invention has the characteristics. Additionally, when the cathode of Comparative Example 3b is applied, it can be confirmed that there is an excess of long SWCNT clusters and the average number length is also long, which causes problems in the coating process. And, when the negative electrode of Comparative Example 4b was applied, although the length characteristics were satisfactory, the particle size characteristics of the dispersion liquid did not differ significantly from those of the examples in that the SWCNT clusters had a large number average diameter compared to the length, so it can be seen that no problem occurred during dispersion. However, it can be confirmed that the capacity retention rate was low as a result of the overall conductive network not being well formed within the electrode due to the relatively large diameter compared to the length. It was confirmed that Comparative Examples 5b and 6b showed similar results to Comparative Example 4b because SWCNT clusters with thick diameters were relatively abundant. Furthermore, in the case where the cathode of Comparative Example 7b was applied, although the number of long SWCNT clusters was small, it was expected that there would be a higher possibility of dispersion problems compared to the case where the cathode of Example 4b was applied due to the difference in the average length, and it was also found that the capacity retention rate was inferior by about 10%. Comparative Example 8b, similar to the case where the cathode of Comparative Example 3b was applied, showed that problems occurred in the dispersion phase due to the excessive presence of long SWCNT clusters, which caused problems in the coating process. In the case where the cathode of Comparative Example 9b was applied, the capacity retention rate was very poor, suggesting that the short length and thin diameter prevented the formation of a conductive network normally.

Claims

1. Contains single-walled carbon nanotube (SWCNT) clusters, The above SWCNT cluster is The average length of the particles is 0.8 ㎛ to 8.0 ㎛, The number of SWCNT clusters exceeding 10 μm in length is less than 15% of the total number, The average diameter of the particles is 5 nm to 25 nm, SWCNT clusters with a diameter exceeding 30 nm account for less than 15% of the total number, The length and diameter of the SWCNT clusters above were measured using an atomic force microscope, a conductive dispersion.

2. In claim 1, The above SWCNT clusters are a conductive dispersion having an average length of 1.0 μm to 6.0 μm.

3. In claim 1, The above SWCNT cluster is a conductive dispersion in which SWCNT clusters having a length exceeding 10 μm account for 10% or less of the total number of SWCNT clusters.

4. In claim 1, The above SWCNT clusters are a conductive dispersion having an average diameter of 7 nm to 20 nm.

5. In claim 1, The above SWCNT cluster is a conductive dispersion having SWCNT clusters having a diameter exceeding 30 nm in an amount of 10% or less with respect to the total number.

6. In claim 1, The above-mentioned conductive dispersion further contains a dispersant, A conductive dispersion liquid comprising at least one dispersant selected from the group consisting of polyacrylate, polyvinylidene fluoride, polyvinylpyrrolidone, polyvinyl alcohol, polyacrylamide, polyethylene oxide, carboxymethyl cellulose, and diisopropylamine.

7. In claim 6, For 100 parts by weight of the above-mentioned conductive dispersion, 0.2 to 3.5 parts by weight of SWCNT clusters and A conductive dispersion comprising 0.2 to 7.0 parts by weight of a dispersant.

8. An electrode active material layer including an electrode active material, a single-walled carbon nanotube (SWCNT) cluster, and a binder is disposed on a current collector, The above SWCNT cluster is The average length of the particles is 0.8 ㎛ to 8.0 ㎛, The number of SWCNT clusters exceeding 10 μm in length is less than 15% of the total number, The average diameter of the particles is 5 nm to 30 nm, SWCNT clusters with a diameter exceeding 30 nm account for less than 15% of the total number, The length and diameter of the above SWCNT clusters were measured using an atomic force microscope.

9. In claim 8, The above electrode active material is a positive electrode active material, An electrode wherein the positive electrode active material comprises at least one selected from the group consisting of lithium nickel-ternary oxide, lithium manganese oxide, lithium iron phosphate, lithium nickel oxide, lithium cobalt oxide, and lithium manganese oxide.

10. In claim 8, The above electrode active material is a negative electrode active material, An electrode wherein the negative active material comprises at least one selected from the group consisting of carbon particles, silicon particles, and carbon-silicon composite particles.

11. In claim 8, The above electrode further includes a point-shaped conductive material, The above dot-shaped conductive material is an electrode containing carbon black.

12. It has a structure in which the anode, separator, and cathode are sequentially stacked. A lithium secondary battery, wherein at least one of the positive and negative electrodes is an electrode according to claim 8.