[One][Citation with related applications] [2] This application claims the benefit of priority based on Korean Patent Application No. 10-2019-0057722 filed on May 17, 2019, and all contents disclosed in the Korean Patent Application Document are incorporated as a part of this specification. [3] [4] [Technical field] [5] The present invention relates to a conductive material dispersion, an electrode manufactured using the same, and a lithium secondary battery. More specifically, the present invention uses a copolymer including a specific unit together with a nitrile-based copolymer as the main dispersant as an auxiliary dispersant, thereby providing a conductive material dispersion having low viscosity characteristics, an electrode and a lithium secondary battery prepared using the same. is about [6] background [7] A secondary battery is a battery that can be used repeatedly through a charging process in the opposite direction to a discharge in which chemical energy is converted into electrical energy. A secondary battery is composed of a positive electrode, a negative electrode, an electrolyte, and a separator, and the positive electrode and the negative electrode generally include an electrode current collector and an electrode active material layer formed on the electrode current collector. The electrode active material layer is prepared by applying an electrode slurry composition including an electrode active material, a conductive material, a binder, etc. on an electrode current collector, drying the composition, and then rolling. [8] The conductive material is to improve the conductivity of the electrode active material, and fine carbon materials such as carbon black, ketjen black, fullerene, graphene, carbon nanotube (CNT), etc. are mainly used. [9] However, since the carbon material conductive materials are not uniformly dispersed in the electrode slurry composition and easily aggregated, there is a problem in that the conductive material is not evenly distributed in the electrode active material layer when an electrode is formed using the carbon material conductive materials. In order to improve this problem, recently, a conductive material dispersion is prepared by first mixing the conductive material with a dispersing agent such as polyvinyl pyrrolidone (PVP), acrylonitrile-butadiene rubber, etc. in a solvent. A method of applying the conductive material dispersion to an electrode slurry composition has been developed. [10] However, since the viscosity of the conductive material dispersion using the PVP dispersant increases rapidly when the conductive material content is increased, there is a limit in increasing the conductive material content, thereby limiting the improvement of electrical conductivity. [11] On the other hand, in order to lower the viscosity of the conductive material dispersion, it is preferable to use a dispersant having a low weight average molecular weight. There is this. [12] On the other hand, the solid content of the positive electrode slurry is determined according to the solid content of the conductive material dispersion. When the solid content of the positive electrode slurry is high, there are effects such as increased productivity, electrode drying efficiency, improved binder migration, and improved adhesion. Therefore, it is preferable to increase the solid content of the conductive material dispersion, but as the solid content increases, the viscosity increases, resulting in a problem in fairness. [13] Therefore, there is a demand for the development of a conductive material dispersion having a low viscosity characteristic even when the conductive material content is high. [14] DETAILED DESCRIPTION OF THE INVENTION technical challenge [15] The present invention is to solve the above problems, and by using a copolymer including a specific unit together with a nitrile-based copolymer dispersant in the conductive material dispersion as an auxiliary dispersant, a conductive material dispersion having lower viscosity compared to the prior art. would like to provide [16] Another object of the present invention is to provide an electrode and a secondary battery manufactured using the conductive material dispersion. [17] means of solving the problem [18] In one aspect, the present invention is a conductive material dispersion comprising a carbon-based conductive material, a dispersing agent and a dispersion medium, wherein the dispersant comprises a main dispersant and an auxiliary dispersant, the main dispersant is a nitrile-based copolymer, and the auxiliary dispersant is oxy alkylene units; And it provides a conductive material dispersion which is a copolymer including at least one of a styrene unit and an alkylene unit. [19] [20] In another aspect, the present invention provides an electrode including an electrode active material layer formed of an electrode slurry composition including an electrode active material, the conductive material dispersion, a binder, and a solvent. In this case, the electrode may be an anode. [21] [22] In another aspect, the present invention provides a lithium secondary battery comprising a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and an electrolyte, wherein the positive electrode may be the electrode according to the present invention. [23] Effects of the Invention [24] The conductive material dispersion according to the present invention is a conductive material using a nitrile-based copolymer dispersant alone by using a nitrile-based copolymer, a copolymer including an oxyalkylene unit, and a styrene and/or an alkylene unit as a dispersing agent. It has lower viscosity properties compared to dispersions. Accordingly, it is possible to increase the solid content in the conductive material dispersion compared to the prior art, and as a result, effects such as increased productivity, electrode drying efficiency, binder migration improvement, and adhesion improvement during electrode manufacturing can be obtained. [25] Best mode for carrying out the invention [26] The terms or words used in this specification and claims should not be construed as being limited to their ordinary or dictionary meanings, and the inventor may properly define the concept of the term in order to best describe his invention. Based on the principle that there is, it should be interpreted as meaning and concept consistent with the technical idea of ​​the present invention. [27] In this specification, terms such as "comprises", "comprises" or "have" are intended to designate the existence of an embodied feature, number, step, element, or a combination thereof, and one or more other features or It does not exclude the possibility of the presence or addition of numbers, steps, elements, or combinations thereof. [28] In this specification, "specific surface area" is measured by the BET method, and specifically, it can be calculated from the amount of nitrogen gas adsorbed under liquid nitrogen temperature (77K) using BELSORP-mino II manufactured by BEL Japan. [29] In the present specification, "weight average molecular weight (Mw)" refers to a value converted to standard polystyrene measured by gel permeation chromatography (GPC). Specifically, the weight average molecular weight is a value obtained by converting a value measured under the following conditions using GPC, and standard polystyrene manufactured by Agilent system was used to prepare the calibration curve. [30] [31] Meter: Agilent GPC (Agulent 1200 series, USA) [32] Column: Connect 2 PL Mixed B [33] Column temperature: 40°C [34] Eluent: Tetrohydrofuran [35] Flow rate: 1.0 mL/min [36] Concentration: ~ 1 mg/mL (100 μL injection) [37] [38] Hereinafter, the present invention will be specifically described. [39] [40] Conductive material dispersion [41] First, the conductive material dispersion according to the present invention will be described. [42] The conductive material dispersion according to the present invention includes a carbon-based conductive material, a dispersant, and a dispersion medium, wherein the dispersant includes a main dispersant and an auxiliary dispersant, the main dispersant is a nitrile-based copolymer, and the auxiliary dispersant is an oxyalkyl ren units; and at least one of a styrene unit and an aliphatic hydrocarbon unit. [43] [44] Hereinafter, each component of the conductive material dispersion according to the present invention will be described in detail. [45] [46] (1) Carbon-based conductive material [47] The carbon-based conductive material is for improving the conductivity of the electrode, and a carbon-based conductive material generally used in the art, for example, carbon nanotubes or carbon black, may be used. [48] Carbon nanotubes have a graphite sheet having a nano-sized cylinder shape and an sp2 bonding structure, and exhibit characteristics of a conductor or a semiconductor according to an angle and structure at which the graphite sheet is rolled. Carbon nanotubes are single-walled carbon nanotube (SWCNT), double-walled carbon nanotube (DWCNT), and multi-walled carbon nanotube (MWCNT) depending on the number of bonds in the wall. carbon nanotubes), and these carbon nanotubes may be appropriately selected according to the use of the dispersion. [49] In addition, the carbon nanotubes may have a secondary shape formed by aggregating or arranging a plurality of carbon nanotubes, for example, a bundle ( It may be a bundle type carbon nanotube in the form of a bundle or rope, or an entangled type carbon nanotube in the form of a sphere or potato in which a plurality of carbon nanotubes are entangled without a specific direction. In terms of dispersibility, the carbon nanotubes are more preferably bundled carbon nanotubes. [50] [51] Meanwhile, as the carbon black, commercially available furnace black, channel black, thermal black, acetylene black, Ketjen black or hollow carbon black may be used, and the type thereof is not particularly limited. [52] If necessary, the carbon black may be surface-treated by a method known in the art. For example, the carbon black may have impurities removed by surface treatment with acetylene gas. In addition, the carbon black may be used with a purity of 99.5% or more. [53] Meanwhile, the carbon-based conductive material used in the present invention may have a BET specific surface area of ​​1000 m 2 /g or less, preferably 30 to 1000 m 2 /g. When the BET specific surface area of ​​the carbon-based conductive material exceeds 1000 m 2 /g, dispersion may not be performed smoothly. [54] Specifically, when the carbon-based conductive material is a carbon nanotube, the BET specific surface area of ​​the carbon nanotube is 100 to 1000 m 2 /g, 150 to 800 m 2 /g, 150 to 500 m 2 /g, 150 to 300 m 2 /g or 150 to 200 m 2 /g. [55] When the carbon-based conductive material is carbon black, the BET specific surface area of ​​the carbon black is 30 to 1000 m 2 /g, preferably 30 to 400 m 2 /g, more preferably 30 to 380 m 2 /g, even more Preferably, it may be 30 to 150 m 2 /g. [56] [57] On the other hand, the content of the carbon-based conductive material in the conductive material dispersion may be 0.1 to 30% by weight, preferably 1 to 30% by weight. Specifically, when the carbon-based conductive material is carbon nanotubes, the content of the carbon-based conductive material in the conductive material dispersion may be 0.1 to 10% by weight, preferably 1 to 8% by weight, and when the carbon-based conductive material is carbon black It may be 1 to 30% by weight, preferably 1 to 25% by weight. When the content of the carbon-based conductive material is too small, a loading amount is reduced during electrode manufacturing, which increases process cost, and binder migration occurs during electrode drying, thereby reducing adhesive strength. On the other hand, if the content of the carbon-based conductive material is too high, there is a problem that the viscosity of the conductive material dispersion increases. [58] [59] (2) dispersant [60] The conductive material dispersion according to the present invention includes two kinds of dispersants. Specifically, the conductive material dispersion according to the present invention includes a copolymer including a nitrile-based copolymer as a main dispersant, an oxyalkylene unit as an auxiliary dispersant, and at least one of a styrene unit and an aliphatic hydrocarbon unit. . [61] [62] 2-1) main dispersant [63] The main dispersant is for improving the dispersibility of the conductive material in the conductive material dispersion, and specifically, it may be a copolymer having an α,β-unsaturated nitrile-derived unit and a conjugated diene-derived unit, in this case, the conjugated diene-derived unit may be partially or entirely hydrogenated. The hydrogenation method of the conjugated diene may be carried out through a hydrogenation reaction known in the art, for example, a catalytic hydrogenation reaction using a catalyst system such as Rh, Ru, Pd, Ir, the amount of catalyst, the reaction hydrogen pressure , by controlling the reaction time, etc., it is possible to control the hydrogenation rate. [64] [65] The nitrile-based copolymer may be prepared by copolymerizing an α,β-unsaturated nitrile monomer and a conjugated diene-based monomer, and then hydrogenating a C═C double bond in the copolymer. The polymerization reaction and hydrogenation process of the monomers may be performed according to a conventional method. [66] As the α,β-unsaturated nitrile monomer, for example, acrylonitrile or methacrylonitrile may be used, and one type alone or a mixture of two or more types thereof may be used. [67] As the conjugated diene-based monomer, for example, 1,3-butadiene, isoprene, or 2,3-methyl butadiene, and the like, conjugated diene-based monomers having 4 to 6 carbon atoms may be used, and one or two of them may be used. A mixture of the above may be used. [68] [69] On the other hand, in the nitrile-based copolymer, α,β-unsaturated nitrile-derived unit: conjugated diene-derived unit in a weight ratio of 10-50:50-90, preferably 20-40:60-80, more preferably 25- 40: It can be included so that it becomes 60-75. When the content of each unit in the nitrile-based copolymer satisfies the above range, the dispersibility and high temperature characteristics are excellent. Here, the content of the α,β-unsaturated nitrile-derived unit is measured by measuring the amount of nitrogen generated according to the mill oven method of JIS K 6364 and converting the amount of binding thereof from the molecular weight of the α,β-unsaturated nitrile to be measured as the median value of the quantified value. Also, the content of the conjugated diene-derived unit may be calculated by subtracting the weight of the α,β-unsaturated nitrile-derived unit from the total weight of the copolymer. [70] [71] On the other hand, in the nitrile-based copolymer of the present invention, the hydrogenation rate of the conjugated diene-based unit may be 80% or more, preferably 90%. This is because, when a dispersing agent in which unhydrogenated conjugated diene units remain is used, reactivity with the electrolyte increases due to double bonds in the conjugated diene, and high temperature characteristics may deteriorate. [72] [73] According to one embodiment, the nitrile-based copolymer may include a repeating unit represented by the following [Formula 1] and a repeating unit represented by the following [Formula 2]. [74] [Formula 1] [75] [76] [Formula 2] [77] [78] In this case, the content of the repeating unit represented by the [Formula 1] may be 10 to 50% by weight, preferably 20 to 40% by weight, more preferably 25 to 40% by weight, and as the [Formula 2] The content of the indicated repeating unit may be 50 to 90% by weight, preferably 60 to 80% by weight, more preferably 60 to 75% by weight. [79] [80] On the other hand, the main dispersant has a weight average molecular weight of 10,000 to 500,000 g/mol, preferably 20,000 to 400,000 g/mol, more preferably 20,000 to 300,000 g/mol, even more preferably 20,000 to 100,000 g/mol can When the weight average molecular weight of the main dispersant satisfies the above range, the conductive material can be uniformly dispersed with a small amount of the dispersant, and the solution viscosity can be prevented from becoming excessively high when the conductive material is dispersed, which is advantageous in terms of process. [81] [82] 2-2) Auxiliary Dispersant [83] The auxiliary dispersant assists the main dispersant to improve dispersibility of the conductive material, and is a copolymer including an oxyalkylene unit and a styrene unit and/or an alkylene unit. [84] The oxyalkylene unit may be represented by the following formula (3). [85] [Formula 3] [86] [87] In Formula 3, [88] R 1 is an alkylene group having 1 to 20 carbon atoms, preferably an alkylene group having 2 to 10 carbon atoms, more preferably an alkylene group having 2 to 5 carbon atoms. [89] The oxyalkylene unit may be included in an amount of 5 to 85% by weight, preferably 9 to 85% by weight, based on the total weight of the copolymer. The content of the oxyalkylene unit in the auxiliary dispersant copolymer exceeds 85% by weight. In this case, the effect of improving the viscosity of the conductive material dispersion is insignificant. [90] [91] The styrene unit may be represented by the following formula (4). [92] [Formula 4] [93] [94] In Formula 4, R 2 may be hydrogen, halogen, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or a combination thereof. [95] The styrene unit may be included in an amount of 70% by weight or less, preferably 5 to 50% by weight, and more preferably 10 to 40% by weight based on the total weight of the copolymer. When the content of the styrene-derived unit satisfies the above range, the effect of reducing the viscosity of the conductive material dispersion is more excellent. [96] [97] The alkylene unit may be represented by the following [Formula 5]. [98] [Formula 5] [99] [100] In Formula 5, n may be an integer of 1 to 50, preferably an integer of 3 to 30. [101] The alkylene unit may be included in 90 wt% or less, preferably 0 wt% to 85 wt%, more preferably 15 to 60 wt% based on the total weight of the copolymer. When the content of the alkylene unit satisfies the above range, the effect of reducing the viscosity of the conductive material dispersion is more excellent. [102] Specifically, the auxiliary dispersant copolymer according to the present invention is a copolymer including an oxyalkylene unit and a styrene unit, a copolymer including an oxyalkylene unit and an alkylene unit, or an oxyalkylene unit, a styrene unit and an alkyl It may be a copolymer including a ren unit. [103] [104] According to the research of the present inventors, when a copolymer including a combination of specific units as described above is used together with a nitrile-based copolymer as the main dispersing agent, when the nitrile-based copolymer is used alone or different from the nitrile-based copolymer It was found that the viscosity of the conductive material dispersion was significantly reduced compared to the case of using a type of auxiliary dispersant. [105] [106] On the other hand, the auxiliary dispersant copolymer of the present invention as described above may be prepared using a copolymer preparation method well known in the art. For example, the auxiliary dispersant copolymer may be prepared by polymerization reaction of compounds capable of inducing each unit, or may be prepared by reacting a compound including each unit through an acid-base reaction, etc. there is. . [107] Examples of the compound capable of deriving an oxyalkylene unit include polyalkylene glycol such as polyethylene glycol and polypropylene glycol, and alkylene oxide compounds such as (poly) ethylene oxide and (poly) propylene oxide, etc. may be used, but is not limited thereto. [108] As a compound from which a styrene unit can be derived, for example, styrene, α-methyl styrene, vinyltoluene, chloromethylstyrene, chlorostyrene, bromostyrene, vinylbenzenesulfonate, methoxymethylstyrene, benzyl (meth) An acrylate or the like may be used, but is not limited thereto. [109] As the compound capable of deriving an alkylene unit, for example, an alkyl (meth)acrylate monomer, an alkene monomer, or the like can be used. Examples of the alkyl (meth) acrylate monomer include methyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, n-amyl (meth)acrylate, isoamyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-ethylbutyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate , cyclohexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, tri Decyl (meth) acrylate, tetradecyl (meth) acrylate, octadecyl (meth) acrylate, isobornyl (meth) acrylate and the like may be mentioned, but is not limited thereto. [110] Examples of the alkene monomer include, but are not limited to, propene, butene, pentene, hexene, heptene, octene, nonene, decene, dodecene, tridecene, tetradecene, and octadecene. [111] On the other hand, as a compound containing each unit, for example, polyalkylene glycol, polyalkylene-styrene copolymer, styrene-maleic anhydride copolymer, polyalkylene imine, oxyalkylene and/or alkylene A surfactant including a unit may be used, but is not limited thereto. [112] [113] Meanwhile, the auxiliary dispersant may have a weight average molecular weight of 800 to 50,000 g/mol, preferably 800 to 30,000 g/mol. When the weight average molecular weight of the auxiliary dispersant satisfies the above range, the effect of reducing the viscosity of the conductive material dispersion was excellent. [114] [115] On the other hand, in the conductive material dispersion of the present invention, the main dispersant and the auxiliary dispersant are 30: 70 to 90: 10, preferably 50: 50 to 90: 10, more preferably 60: 40 to 90: 10 by weight may be included as a percentage. When the content of the main dispersant is less than the above range, the conductive material is not smoothly dispersed, and thus the effect of improving the viscosity is insignificant. In addition, when the ratio of the main dispersant in the total dispersant is 50% or more, the effect of improving the viscosity is more excellent. [116] [117] (3) dispersion medium [118] The dispersion medium may be an organic solvent containing any one or two or more heteroatoms selected from the group consisting of a nitrogen atom (N) and an oxygen atom (O) having a lone pair of electrons. [119] Specifically, the dispersion medium is an amide-based polar organic solvent such as dimethylformamide (DMF), diethyl formamide, dimethyl acetamide (DMAc), N-methyl pyrrolidone (NMP); Methanol, ethanol, 1-propanol, 2-propanol (isopropyl alcohol), 1-butanol (n-butanol), 2-methyl-1-propanol (isobutanol), 2-butanol (sec-butanol), 1-methyl alcohols such as -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; 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 glycol ethers such as 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, methylpropyl ketone, or cyclopentanone; and esters such as ethyl acetate, γ-butyl lactone, and ε-propiolactone, and any one or a mixture of two or more thereof may be used. Among these, N-methyl pyrrolidone (NMP) is particularly preferable in consideration of compatibility with the electrode slurry. [120] [121] The conductive material dispersion of the present invention including the above components may be prepared by mixing a carbon-based conductive material, a main dispersant, an auxiliary dispersant, and a dispersion medium. At this time, the mixing may be performed using a conventional mixing method, specifically, a mixing device such as a homogenizer, bead mill, ball mill, basket mill, attrition mill, universal stirrer, clear mixer, spike mill or TK mixer. and the mixing order of each component is not particularly limited. That is, the conductive material dispersion according to the present invention may be prepared by adding a carbon-based conductive material to the dispersion medium, then adding a main dispersing agent and an auxiliary dispersing agent and mixing them. It may be formed by a method of mixing the conductive material, or it may be formed by adding the main dispersant, the auxiliary dispersing agent, and the carbon-based conductive material together to the dispersion medium and then mixing. [122] Meanwhile, in the mixing process, a cavitation dispersion treatment may be performed to increase the dispersibility of the carbon-based conductive material. The cavitation dispersion treatment is a dispersion treatment method using a shock wave generated by the rupture of vacuum bubbles generated in water when high energy is applied to a liquid. By this method, the carbon-based conductive material can be dispersed without impairing the properties. . Specifically, the cavitation dispersion treatment may be performed by ultrasonic wave, jet mill, or shear dispersion treatment. [123] [124] On the other hand, since the dispersibility of the conductive material is affected by the type and specific surface area of ​​the conductive material used, in order to obtain an excellent effect of reducing the viscosity, it is necessary to appropriately control the contents of the conductive material and the dispersant according to the specific surface area value of the conductive material used. . As a result of repeated research, the present inventors have found that a viscosity reduction effect can be obtained when the specific surface area of ​​the conductive material and the content of each component satisfy a specific relationship expressed by the following formula (1). [125] Specifically, the conductive material dispersion according to the present invention is preferably configured such that the conductive material specific surface area and the contents of the conductive material and the dispersant in the conductive material dispersion satisfy the following formula (1). [126] Equation (1): 0.07A ≤ {(W1+W2)/W3}×100 ≤ 0.3A [127] In this case, in Formula (1), W1 is the weight% of the main dispersant in the conductive material dispersion, W2 is the weight% of the auxiliary dispersant in the conductive material dispersion, and W3 is the weight% of the conductive material in the conductive material dispersion. and A means the BET specific surface area (unit: m 2 /g) value of the used conductive material. [128] When the conductive material dispersion satisfies Equation (1), the conductive material can be sufficiently wetted, thereby maximizing the effect of reducing the viscosity of the conductive material dispersion. [129] [130] According to one embodiment, the conductive material dispersion according to the present invention includes a nitrile-based copolymer having a weight average molecular weight of 10,000 to 100,000 g/mol as a main dispersing agent, and an oxyalkylene unit, a styrene unit and an alkylene unit as an auxiliary dispersant. It may include a copolymer comprising a carbon-based conductive material, and a BET specific surface area of ​​150 to 200 m 2 /g carbon nanotubes as a carbon-based conductive material. When the main dispersant, the auxiliary dispersant, and the carbon-based conductive material satisfy the above combination, the effect of reducing the viscosity is very excellent. [131] [132] electrode [133] Next, an electrode according to the present invention will be described. [134] The electrode according to the present invention includes an electrode active material layer formed of an electrode slurry composition including an electrode active material, a conductive material dispersion, and a binder. Specifically, the electrode may include an electrode current collector and an electrode active material layer formed on the electrode current collector, and the electrode active material layer may be formed by an electrode slurry composition including an electrode active material, a conductive material dispersion, and a binder. there is. [135] At this time, the conductive material dispersion liquid is the conductive material dispersion liquid according to the present invention described above. Since the content of the conductive material dispersion is the same as described above, a detailed description will be omitted, and the remaining components will be described below. [136] [137] The electrode current collector is not particularly limited as long as it is a material having conductivity without causing chemical change in the battery, for example, copper, stainless steel, aluminum, nickel, titanium, alloys thereof, carbon, nickel, Those surface-treated with titanium, silver, or the like, or calcined carbon, etc. may be used. [138] The electrode current collector may typically have a thickness of 3 μm to 500 μm, and may form fine irregularities on the surface of the current collector to strengthen the bonding force of the negative electrode active material. In addition, the electrode current collector may be used in various forms such as, for example, a film, a sheet, a foil, a net, a porous body, a foam, a nonwoven body, and the like. [139] Meanwhile, the electrode active material (a) included in the electrode active material layer may be a positive active material or a negative active material generally used in the art, and the type is not particularly limited. [140] For example, a lithium oxide including lithium and one or more metals such as cobalt, manganese, nickel, or aluminum may be used as the positive electrode active material. More specifically, the lithium oxide is a lithium-manganese oxide (eg, LiMnO 2 , LiMn 2 O, etc.), a lithium-cobalt-based oxide (eg, LiCoO 2 etc.), a lithium-nickel-based oxide (eg, For example, LiNiO 2 etc.), lithium-nickel-manganese oxide (for example, LiNi 1-Y1 Mn Y1 O2 (here, 0