Carbon nanotube dispersion composition and preparation method thereof

Abstract

The present invention relates to a carbon nanotube dispersion composition and a preparation method thereof. More specifically, the present invention relates to a carbon nanotube dispersion composition and a preparation method thereof, the carbon nanotube dispersion composition comprising: carbon nanotubes; a hydrated nitrile butadiene rubber as a first dispersant; 4-[4-[1,1-bis(4-hydroxyphenyl)ethyl]]-a,a-dimethylbenzylphenol as a second dispersant; a basic additive; and a solvent. The carbon nanotube dispersion composition according to the present invention can significantly reduce the viscosity of a dispersion and thereby improve dispersibility, and can improve conductivity when used as a conductive material.

Description

Carbon nanotube dispersion composition and method for producing the same

[0001] The present invention relates to a carbon nanotube dispersion composition and a method for producing the same. More specifically, the present invention relates to a carbon nanotube dispersion composition comprising carbon nanotubes, hydrated nitrile butadiene rubber as a first dispersing agent, 4-[4-[1,1-bis(4-hydroxyphenyl)ethyl]]-a,a-dimethylbenzylphenol as a second dispersing agent, a basic additive, and a solvent, and a method for producing the same.

[0002]

[0003] Secondary batteries consist of a cathode, anode, an electrolyte, and a separator. The anode and cathode are composed of a conductive material, a binder, and an electrode active material. The conductive material facilitates electron movement between the electrode active materials and enhances the electrode's conductivity. The most commonly used conductive material is carbon-based, which offers the advantages of low cost and light weight.

[0004] Carbon-based conductive materials include carbon black, Ketjen black, fullerene, graphene, and carbon nanotubes (CNTs). Often, two or more conductive materials are used in combination to enhance conductivity and other properties. Among these, carbon nanotubes can achieve high conductivity with small amounts, allowing for the addition of more electrode active materials to compensate for the reduced amount of conductive material used. The addition of electrode active materials increases the capacity of the secondary battery, resulting in improved battery performance. Despite these excellent properties, carbon nanotubes have a strong tendency to clump together, making them difficult to disperse in solvents.

[0005] To improve this, various dispersants are used to prepare dispersions, and physical methods such as ball milling or high-pressure dispersion are used to disperse carbon nanotubes in the dispersions. However, if the dispersant is used excessively, the electrical conductivity of the conductive material decreases, which causes the problem of deterioration in the conductive material quality. Furthermore, due to the large specific surface area of ​​carbon nanotubes and the compatibility issue of the dispersant, the dispersion efficiency decreases, causing a rapid increase in viscosity, making it difficult to increase the carbon nanotube solid content. There is a need for a carbon nanotube dispersion composition that can solve these conventional problems, effectively disperse carbon nanotubes, and increase the carbon nanotube solid content.

[0006]

[0007] Prior art literature

[0008] Patent Document 1. Republic of Korea Patent Publication No. 2015-0016852

[0009]

[0010] The present inventors have made extensive efforts to prepare a carbon nanotube dispersion composition having excellent dispersibility and conductivity when used as a conductive material, and as a result, have confirmed that when hydrated nitrile butadiene rubber and 4-[4-[1,1-bis(4-hydroxyphenyl)ethyl]]-a,a-dimethylbenzylphenol are used together as a dispersant, the carbon nanotube dispersion not only has a low viscosity of less than 3,000 cps but also exhibits a low electrode resistance of less than 10 Ωcm when used as a conductive material (see Table 2), and thus have completed the present invention.

[0011]

[0012] Accordingly, the present invention aims to provide a carbon nanotube dispersion composition comprising hydrated nitrile butadiene rubber and 4-[4-[1,1-bis(4-hydroxyphenyl)ethyl]]-a,a-dimethylbenzylphenol as a dispersant.

[0013] The present invention also aims to provide a method for producing a carbon nanotube dispersion composition comprising hydrated nitrile butadiene rubber and 4-[4-[1,1-bis(4-hydroxyphenyl)ethyl]]-a,a-dimethylbenzylphenol as dispersants.

[0014] The objectives of the present invention are not limited to those mentioned above. Other objectives and advantages of the present invention not mentioned above can be understood through the following description and will be more clearly understood through the embodiments of the present invention. Furthermore, it will be readily apparent that the objectives and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims.

[0015]

[0016] The present invention discloses a carbon nanotube dispersion composition and a method for producing the same.

[0017]

[0018] According to the first implementation example,

[0019] carbon nanotubes;

[0020] Hydrogenated nitrile butadiene rubber as a first dispersant;

[0021] 4-[4-[1,1-bis(4-hydroxyphenyl)ethyl]]-a,a-dimethylbenzylphenol as a second dispersant;

[0022] alkaline additives; and

[0023] menstruum

[0024] A carbon nanotube dispersion composition including is disclosed.

[0025] In the present invention, the carbon nanotubes may be included in an amount of 2 to 20 wt% based on the total weight of the carbon nanotube dispersion composition.

[0026] In the present invention, the hydrogenated nitrile butadiene rubber may be included in an amount of 0.3 to 3.5 wt% based on the total weight of the carbon nanotube dispersion composition.

[0027] In the present invention, the hydrogenated nitrile butadiene rubber may be included in an amount of 15 to 25 wt% based on 100 wt% of carbon nanotubes.

[0028] In the present invention, the 4-[4-[1,1-bis(4-hydroxyphenyl)ethyl]]-a,a-dimethylbenzylphenol may be included in an amount of 0.5 to 5 wt% based on 100 wt% of carbon nanotubes.

[0029] In the present invention, the second dispersing agent may further include polyphenol.

[0030] In the present invention, the second dispersant may be included in an amount of 1 to 5 wt% based on 100 wt% of carbon nanotubes.

[0031] In the present invention, the basic additive may include N-methylethanolamine, ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, 2-amino-1-propanol, 3-amino-1-propanol, isopropanolamine, diisopropanolamine, triisopropanolamine, N-methylisopropanolamine, N-ethylisopropanolamine, N-propylisopropanolamine, or a combination thereof.

[0032] In the present invention, the basic additive may be included in an amount of 2 to 5.5 wt% based on 100 wt% of carbon nanotubes.

[0033] In the present invention, the pH of the dispersion may be 8 to 11.

[0034] In the present invention, the carbon nanotube dispersion composition may include 2 to 20 wt% of carbon nanotubes, 0.3 to 3.5 wt% of hydrogenated nitrile butadiene rubber, 0.5 to 5 wt% of 4-[4-[1,1-bis(4-hydroxyphenyl)ethyl]]-a,a-dimethylbenzylphenol, 2 to 5.5 wt% of an amine compound, and the remainder of a solvent.

[0035] In the present invention, the average particle diameter (D50) of the carbon nanotube dispersion may be 0.1 μm to 10 μm.

[0036] In the present invention, the viscosity of the carbon nanotube dispersion liquid under 25°C conditions may be less than 3,000 cPs.

[0037]

[0038] According to the second implementation example,

[0039] A step of mixing a carbon nanotube dispersion composition comprising carbon nanotubes, hydrated nitrile butadiene rubber, 4-[4-[1,1-bis(4-hydroxyphenyl)ethyl]]-a,a-dimethylbenzylphenol, a basic additive, and a solvent; and

[0040] A method for producing a carbon nanotube dispersion composition is disclosed, which comprises a step of dispersing the carbon nanotube dispersion composition.

[0041] In the present invention, the step of mixing the carbon nanotube dispersion composition can be performed at 1,000 to 3,000 rpm for 30 minutes to 2 hours.

[0042]

[0043] The carbon nanotube dispersion composition according to the present invention can significantly reduce the viscosity of the dispersion and improve dispersibility by using 4-[4-[1,1-bis(4-hydroxyphenyl)ethyl]]-a,a-dimethylbenzylphenol as a dispersant together with hydrated nitrile butadiene rubber, and can improve conductivity when used as a conductive material.

[0044]

[0045] Therefore, when the carbon nanotube dispersion composition according to the present invention is used as a conductive material in the manufacture of a secondary battery electrode, its performance as a conductive material can be maximized, and accordingly, it is expected that the conductivity of the electrode of the secondary battery can be improved and the performance of the secondary battery can be enhanced.

[0046]

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In general, the nomenclature used herein is well known and commonly used in the art.

[0048] Additionally, throughout this specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless specifically stated otherwise.

[0049] The term "carbon nanotube dispersion" as used herein refers to a dispersion containing carbon nanotubes. Specifically, it refers to a dispersion in which carbon nanotubes are dispersed and do not aggregate with each other.

[0050]

[0051] 1. Carbon nanotube dispersion composition

[0052] The present invention

[0053] carbon nanotubes;

[0054] Hydrogenated nitrile butadiene rubber as a first dispersant;

[0055] 4-[4-[1,1-bis(4-hydroxyphenyl)ethyl]]-a,a-dimethylbenzylphenol as a second dispersant;

[0056] alkaline additives; and

[0057] menstruum

[0058] It is intended to provide a carbon nanotube dispersion composition including .

[0059] In the carbon nanotube dispersion composition according to the present invention, the carbon nanotubes may be included in an amount of 2 to 20 wt% based on the total weight of the carbon nanotube dispersion composition. If the content of the carbon nanotubes is less than 2 wt%, the slurry solids content is low during the preparation of the electrode slurry, which is disadvantageous for electrode coating, and if the content of the carbon nanotubes exceeds 20 wt%, problems may occur in the process due to an increase in the viscosity of the dispersion.

[0060] In the carbon nanotube dispersion composition according to the present invention, the carbon nanotubes may include single-walled carbon nanotubes, multi-walled carbon nanotubes, or a combination thereof.

[0061] In the carbon nanotube dispersion composition according to the present invention, the hydrogenated nitrile butadiene rubber may be included in an amount of 0.3 to 3.5 wt% based on the total weight of the carbon nanotube dispersion composition. If the content of the hydrogenated nitrile butadiene rubber is less than 0.3 wt%, the dispersibility of the carbon nanotubes may be reduced, and if the content of the hydrogenated nitrile butadiene rubber exceeds 3.5 wt%, the viscosity of the entire dispersion may be increased.

[0062] In the carbon nanotube dispersion composition according to the present invention, the weight average molecular weight (Mw) of the hydrogenated nitrile butadiene rubber may be 120,000 to 300,000. If the weight average molecular weight of the hydrogenated nitrile butadiene rubber is outside the above range, viscosity control is difficult, carbon nanotube dispersion performance is reduced, carbon nanotubes re-agglomerate, and an overall quality deterioration problem occurs.

[0063] In the carbon nanotube dispersion composition according to the present invention, the polydispersity index (PDI) of the hydrogenated nitrile butadiene rubber may be 1.1 to 1.3.

[0064] In the carbon nanotube dispersion composition according to the present invention, the hydrogenated nitrile butadiene rubber may be included in an amount of 15 to 25 wt% based on 100 wt% of carbon nanotubes. If the content of the hydrogenated nitrile butadiene rubber is less than 15 wt% based on 100 wt% of carbon nanotubes, the dispersibility of the carbon nanotubes may be reduced, and if the content of the hydrogenated nitrile butadiene rubber exceeds 25 wt% based on 100 wt% of carbon nanotubes, the viscosity of the entire dispersion may be increased.

[0065] In the carbon nanotube dispersion composition according to the present invention, the 4-[4-[1,1-bis(4-hydroxyphenyl)ethyl]]-a,a-dimethylbenzylphenol may be included in an amount of 0.5 to 5 wt% based on 100 wt% of carbon nanotubes. If the content of the 4-[4-[1,1-bis(4-hydroxyphenyl)ethyl]]-a,a-dimethylbenzylphenol is less than 0.5 wt% based on 100 wt% of carbon nanotubes, the dispersibility of the carbon nanotubes may be reduced, and if the content of the 4-[4-[1,1-bis(4-hydroxyphenyl)ethyl]]-a,a-dimethylbenzylphenol exceeds 5 wt% based on 100 wt% of carbon nanotubes, the viscosity of the entire dispersion may be increased. The chemical formula of 4-[4-[1,1-bis(4-hydroxyphenyl)ethyl]]-a,a-dimethylbenzylphenol is as shown in Chemical Formula 1 below.

[0066] [Chemical Formula 1]

[0067]

[0068] In the carbon nanotube dispersion composition according to the present invention, the second dispersant may further include polyphenol. In this case, the second dispersant may be included in an amount of 1 to 5 wt% based on 100 wt% of carbon nanotubes. If the content of the second dispersant is less than 1 wt% based on 100 wt% of carbon nanotubes, the dispersibility of the carbon nanotubes may be reduced, and if the content of the second dispersant exceeds 5 wt% based on 100 wt% of carbon nanotubes, the viscosity of the entire dispersion may be increased.

[0069] In the carbon nanotube dispersion composition according to the present invention, the polyphenol may include tannic acid of the following chemical formula 2.

[0070] [Chemical Formula 2]

[0071]

[0072] In the carbon nanotube dispersion composition according to the present invention, the second dispersant may be included in an amount of 5 to 25 wt% based on 100 wt% of the first dispersant. If the content of the second dispersant is less than 5 wt% based on 100 wt% of the first dispersant, viscosity may increase and electrical conductivity may decrease, and if the content of the second dispersant exceeds 25 wt% based on 100 wt% of the first dispersant, viscosity of the entire dispersion may increase, electrical conductivity may decrease, and a gelation phenomenon may occur.

[0073] In the carbon nanotube dispersion composition according to the present invention, the basic additive may include an amine compound including N-methylethanolamine, ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, 2-amino-1-propanol, 3-amino-1-propanol, isopropanolamine, diisopropanolamine, triisopropanolamine, N-methylisopropanolamine, N-ethylisopropanolamine, N-propylisopropanolamine, or a combination thereof, but is not limited thereto.

[0074] In the carbon nanotube dispersion composition according to the present invention, the basic additive may be included in an amount of 2 to 5.5 wt% based on 100 wt% of carbon nanotubes. If the content of the basic additive is less than 2 wt% based on 100 wt% of carbon nanotubes, the dispersibility of the carbon nanotubes may be reduced, and if the content of the basic additive exceeds 5.5 wt% based on 100 wt% of carbon nanotubes, the pH of the dispersion may rapidly increase, causing a large number of defects in the carbon nanotubes.

[0075] In the carbon nanotube dispersion composition according to the present invention, the solvent may include, but is not limited to, NMP, pyridine, morpholine, dimethylaminobenzene, diethylaminobenzene, n-butylamine, methanol, ethanol, propanol, butanol, or a combination thereof. The content of the solvent is used as the remainder of the carbon nanotube dispersion composition, and may be included in an amount of, for example, 75 to 99 wt% based on the total weight of the carbon nanotube dispersion composition.

[0076] In the carbon nanotube dispersion composition according to the present invention, the pH of the dispersion may be 8 to 11, preferably 8.5 to 10.5. If the pH of the dispersion is less than 8 or greater than 11, the dispersibility of the carbon nanotubes may be reduced.

[0077] In one exemplary embodiment of the present invention, the carbon nanotube dispersion composition may include 2 to 20 wt% of carbon nanotubes, 0.3 to 3.5 wt% of hydrogenated nitrile butadiene rubber, 0.5 to 5 wt% of 4-[4-[1,1-bis(4-hydroxyphenyl)ethyl]]-a,a-dimethylbenzylphenol, 2 to 5.5 wt% of an amine compound, and the remainder of a solvent.

[0078] In one exemplary embodiment of the present invention, the carbon nanotube dispersion composition may include 2 to 20 wt% of carbon nanotubes, 0.3 to 3.5 wt% of hydrogenated nitrile butadiene rubber, 1 to 5 wt% of tannic acid and 4-[4-[1,1-bis(4-hydroxyphenyl)ethyl]]-a,a-dimethylbenzylphenol, 2 to 5.5 wt% of an amine compound, and the remainder of a solvent.

[0079] In one exemplary embodiment of the present invention, the average particle diameter (D50) of the carbon nanotubes may be 0.1 μm to 10 μm, preferably 0.4 μm to 6 μm. The average particle diameter (D50) refers to a particle diameter corresponding to 50% of the accumulated number of carbon nanotubes in a particle diameter distribution curve. The average particle diameter (D50) can be measured using, for example, a laser diffraction method. Within the above range, carbon nanotubes do not aggregate with each other, and dispersibility can be improved.

[0080] In one exemplary embodiment of the present invention, the viscosity of the carbon nanotubes may be less than 5,000 cPs, preferably less than 4,000 cPs, and most preferably less than 3,000 cPs under 25°C conditions. Considering the purpose of the present invention, the lower the viscosity, the better, so the lower limit is not particularly limited, but may be 10 cPs or more, 30 cPs or more, or 50 cPs or more. When the viscosity range is satisfied, the carbon nanotubes of the carbon nanotube dispersion do not aggregate with each other, and the processability may be improved when used in electrode manufacturing.

[0081]

[0082] 2. Method for producing a carbon nanotube dispersion composition

[0083] The present invention

[0084] A step of mixing a carbon nanotube dispersion composition comprising carbon nanotubes, hydrated nitrile butadiene rubber, 4-[4-[1,1-bis(4-hydroxyphenyl)ethyl]]-a,a-dimethylbenzylphenol, a basic additive, and a solvent; and

[0085] A step of dispersing the above carbon nanotube dispersion composition;

[0086] The present invention provides a method for producing a carbon nanotube dispersion composition including:

[0087] In the method for producing a carbon nanotube dispersion composition according to the present invention, the step of mixing the carbon nanotube dispersion composition may be performed at 1,000 to 3,000 rpm for 30 minutes to 2 hours. The mixing may be performed using a shaker, an orbital shaker, a homomixer, or a rotation-rotation mixer.

[0088] In the method for producing a carbon nanotube dispersion composition according to the present invention, the step of dispersing the carbon nanotube dispersion composition can be performed using a homogenizer or a high-pressure homogenizer.

[0089] In the method for producing a carbon nanotube dispersion composition according to the present invention, the carbon nanotube dispersion produced by the method has an average particle diameter (D50) of 0.1 μm to 10 μm, a viscosity of less than 3,000 cPs under 25°C conditions, and an electrode resistance of less than 10 Ωcm.

[0090]

[0091] 3. Electrode slurry composition

[0092] The present invention

[0093] Carbon nanotube dispersion composition;

[0094] electrode active material; and

[0095] An electrode slurry composition for a lithium secondary battery comprising a binder is provided. The carbon nanotube dispersion composition is as described in 1. Carbon nanotube dispersion composition.

[0096] In the electrode slurry composition according to the present invention, the electrode slurry composition may be a positive electrode slurry composition or a negative electrode slurry composition. When the electrode slurry composition is a composition of a positive electrode slurry for forming a positive electrode, the positive electrode can be manufactured by applying the composition of the positive electrode slurry onto a positive electrode current collector, followed by drying and rolling. Alternatively, the positive electrode can be manufactured by casting the positive electrode slurry onto a separate support, and then peeling the film obtained by laminating it onto the positive electrode current collector. When the electrode slurry composition is a composition of a negative electrode slurry for forming a negative electrode, the negative electrode can be manufactured by applying the composition of the negative electrode slurry onto a negative electrode current collector, followed by drying and rolling. Alternatively, the negative electrode can be manufactured by casting the negative electrode slurry onto a separate support, and then peeling the film obtained by laminating it onto the negative electrode current collector.

[0097]

[0098] 4. Lithium secondary battery

[0099] The present invention

[0100] An electrode comprising an electrode active material layer formed by the above electrode slurry composition;

[0101] membrane, and

[0102] A lithium secondary battery including an electrolyte is provided.

[0103] In the lithium secondary battery according to the present invention, the lithium secondary battery may further include a separator that prevents short circuits between the positive and negative electrodes and provides a passage for lithium ions. The separator may be a polyolefin-based polymer film such as polypropylene, polyethylene, polyethylene / polypropylene, polyethylene / polypropylene / polyethylene, polypropylene / polyethylene / polypropylene, or a multi-film thereof, a microporous film, a woven fabric, or a non-woven fabric. In addition, a film coated with a resin having excellent stability on a porous polyolefin film may be used, but is not limited thereto.

[0104] In the lithium secondary battery according to the present invention, the shape of the lithium secondary battery may include a square shape, a cylindrical shape, or a pouch shape.

[0105]

[0106] Hereinafter, the present invention will be described in detail through examples. However, the following examples and experimental examples are merely illustrative of one form of the present invention, and the scope of the present invention is not limited by the following examples and experimental examples.

[0107]

[0108] Preparation of carbon nanotube dispersion

[0109] [Example 1-84]

[0110] Carbon nanotubes, dispersants, basic additives, and solvents were added to a planetary mixer (Thinky ARE-310) according to the compositions shown in Table 1 (unit: g) below, and stirred at 1,700 rpm for 30 minutes to prepare a mixture. The mixture was dispersed 20 times at 1,500 bar using a high-pressure homogenizer (Micronox MN400BF).

[0111]

[0112] [Comparative Example 1-6]

[0113] A carbon nanotube dispersion was prepared using the same method as in the above example according to the composition shown in Table 1 below.

[0114]

[0115] Carbon nanotube 1st dispersant 2nd dispersant base additive solvent type weight type weight type weight type weight type weight Example 1 10B5HNBR 0.85 TA 0.08 TP 0.08 EA 0.20 NMP 9 3.79 Example 2 10B5HNBR 1.00 TA 0.09 TP 0.09 EA 0.20 NMP 9 3.62 Example 3 10B5HNBR 1.10 TA 0.10 TP 0.10 EA 0.20 NMP 9 3.50 Example 4 10B5HNBR 1.00 TA 0.04 TP 0.04 EA 0.20 NMP 9 3.72 Example 5 10B5HNBR 1.00 TA 0.06 TP 0.06 EA 0.20 NMP 9 3.68 Example 610B5HNBR1.00TA0.10TP0.10EA0.20NMP93.60Example 710B5HNBR0.85TA0.08TP0.08EA0.15NMP93.84Example 810B5HNBR0.85TA0.08TP0.08EA0.25NMP93.74Example 910B2.5HNBR0.43TA0.05TP0.05EA0.13NMP96.84Example 1010B9HNBR1.53TA0.18TP0.18EA0.45NMP88.66Example 1110B18HNBR3.06TA0.35TP0.35EA0.90NMP77.34Example 1210B5HNBR0.85TP0.15EA0.20NMP93.80 Example 1310B5HNBR1.00TP0.18EA0.20NMP93.62 Example 1410B5HNBR1.10TP0.20EA0.20NMP93.50 Example 1510B5HNBR1.00TP0.07EA0.20NMP93.73 Example 1610B5HNBR1.00TP0.12EA0.20NMP93.68 Example 1710B5HNBR1.00TP0.20EA0.20NMP93.60 Example 1810B5HNBR0.85TP0.15EA0.15NMP93.85 Example 1910B5HNBR0.85TP0.15EA0.25NMP93.75Example 2010B2.5HNBR0.43TP0.10EA0.13NMP96.84Example 2110B9HNBR1.53TP0.35EA0.45NMP88.67Example 2210B18HNBR3.06TP0.70EA0.90NMP77.34Example 2310B5HNBR0.85TA0.08TP0.08AP0.20NMP93.79 Example 2410B5HNBR1.00TA0.09TP0.09AP0.20NMP93.62 Example 2510B5HNBR1.10TA0.10TP0.10AP0.20NMP93.50 Example 2610B5HNBR1.00TA0.04TP0.04AP0.20NMP93.72 Example 2710B5HNBR1.00TA0.06TP0.06AP0.20NMP93.68 Example 2810B5HNBR1.00TA0.10TP0.10AP0.20NMP93.60 Example 2910B5HNBR0.85TA0.08TP0.08AP0.15NMP93.84 Example 3010B5HNBR0.85TA0.08TP0.08AP0.25NMP93.74Example 3110B2.5HNBR0.43TA0.05TP0.05AP0.13NMP96.84Example 3210B9HNBR1.53TA0.18TP0.18AP0.45NMP88.66Example 3310B18HNBR3.06TA0.35TP0.35AP0.90NMP77.34Example 3410B5HNBR0.85TP0.15AP0.20NMP93.80Example 3510B5HNBR1.00TP0.18AP0.20NMP93.62Example 3610B5HNBR1.10TP0.20AP0.20NMP93.50Example 3710B5HNBR1.00TP0.07AP0.20NMP93.73Example 3810B5HNBR1.00TP0.12AP0.20NMP93.68Example 3910B5HNBR1.00TP0.20AP0.20NMP93.60Example 4010B5HNBR0.85TP0.15AP0.15NMP93.85Example 4110B5HNBR0.85TP0.15AP0.25NMP93.75Example 4210B2.5HNBR0.43TP0.10AP0.13NMP96.84Example 4310B9HNBR1.53TP0.35AP0.45NMP88.67Example 4410B18HNBR3.06TP0.70AP0.90NMP77.34Example 456A2.2HNBR0.37TA0.03TP0.03EA0.09NMP97.28Example 466A2.2HNBR0.44TA0.04TP0.04EA0.09NMP97.19Example 476A2.2HNBR0.48TA0.04TP0.04EA0.09NMP97.15 Example 486A2.2HNBR0.44TA0.02TP0.02EA0.09NMP97.23 Example 496A2.2HNBR0.44TA0.03TP0.03EA0.09NMP97.21 Example 506A2.2HNBR0.44TA0.04TP0.04EA0.09NMP97.19 Example 516A2.2HNBR0.37TA0.03TP0.03EA0.07NMP97.30 Example 526A2.2HNBR0.37TA0.03TP0.03EA0.11NMP97.26 Example 536A3HNBR0.51TA0.06TP0.06EA0.15NMP96.22 Example 546A5HNBR0.85TA0.10TP0.10EA0.25NMP93.70 Example 556A2.2HNBR0.37TP0.07EA0.09NMP97.27 Example 566A2.2HNBR0.44TP0.08EA0.09NMP97.19 Example 576A2.2HNBR0.48TP0.09EA0.09NMP97.14 Example 586A2.2HNBR0.44TP0.03EA0.09NMP97.24 Example 596A2.2HNBR0.44TP0.05EA0.09NMP97.22 Example 606A2.2HNBR0.44TP0.09EA0.09NMP97.18 Example 616A2.2HNBR0.37TP0.07EA0.07NMP97.29 Example 626A2.2HNBR0.37TP0.07EA0.11NMP97.25 Example 636A3HNBR0.51TP0.12EA0.15NMP96.22 Example 646A5HNBR0.85TP0.20EA0.25NMP93.70 Example 656A2.2HNBR0.37TA0.03TP0.03AP0.09NMP97.28 Example 666A2.2HNBR0.44TA0.04TP0.04AP0.09NMP97.19 Example 676A2.2HNBR0.48TA0.04TP0.04AP0.09NMP97.15 Example 686A2.2HNBR0.44TA0.02TP0.02AP0.09NMP97.23 Example 696A2.2HNBR0.44TA0.03TP0.03AP0.09NMP97.21 Example 706A2.2HNBR0.44TA0.04TP0.04AP0.09NMP97.19 Example 716A2.2HNBR0.37TA0.03TP0.03AP0.07NMP97.30 Example 726A2.2HNBR0.37TA0.03TP0.03AP0.11NMP97.26 Example 736A3HNBR0.51TA0.06TP0.06AP0.15NMP96.22 Example 746A5HNBR0.85TA0.10TP0.10AP0.25NMP93.70 Example 756A2.2HNBR0.37TP0.07AP0.09NMP97.27 Example 766A2.2HNBR0.44TP0.08AP0.09NMP97.19 Example 776A2.2HNBR0.48TP0.09AP0.09NMP97.14 Example 786A2.2HNBR0.44TP0.03AP0.09NMP97.24Example 796A2.2HNBR0.44TP0.05AP0.09NMP97.22Example 806A2.2HNBR0.44TP0.09AP0.09NMP97.18Example 816A2.2HNBR0.37TP0.07AP0.07NMP97.29Example 826A2.2HNBR0.37TP0.07AP0.11NMP97.25Example 836A3HNBR0.51TP0.12AP0.15NMP96.22Example 846A5HNBR0.85TP0.20AP0.25NMP93.70Comparative Example 110B5HNBR0.50TA0.05TP0.05EA0.20NMP94.20Comparative example 210B5HNBR0.85EA0.20NMP93.95Comparative example 310B5HNBR0.85TA0.08TP0.08EA0.05NMP93.94Comparative example 46A2.2HNBR0.66TA0.06TP0.06AP0.09NMP96.93Comparative example 56A2.2HNBR0.37TA0.05TP0.05AP0.09NMP97.24Comparative example 66A2.2HNBR0.37TA0.03TP0.03EA0.22NMP97.15.

[0116] - 10B: JENOTUBE 10B (JEIO, multi-walled carbon nanotube)

[0117] - 6A: JENOTUBE 6A (JEIO, thin multi-walled carbon nanotube)

[0118] - HNBR: Hydrogenated nitrile butadiene rubber (ARLANXEO, Therban®AT 3404)

[0119] - TA: Tannic acid

[0120] - TP: 4-[4-[1,1-bis(4-hydroxyphenyl)ethyl]]-a,a-dimethylbenzylphenol (HONSHU CHEMICAL, TrisP-PA)

[0121] - EA: Ethanolamine

[0122] - AP: 3-amino-1-propanol

[0123] - NMP: N-methylpyrrolidone

[0124]

[0125] Characterization of carbon nanotube dispersions

[0126] 1. Evaluation method

[0127] 1) Particle size (D50): The cumulative particle size distribution was measured using a particle size measuring device (HORIBA, LA-960V2).

[0128] 2) Viscosity (cps): Measured using a rotational viscometer (Brookfield, DV2T) at 25℃ with a #64 spindle and 30 rpm.

[0129] 3) Electrode resistance (Ωcm): 70 wt% of cathode active material (NCM622), 6 wt% of carbon nanotube dispersion, 14 wt% of PVDF solution (8 wt% PVDF, 92 wt% NMP), and 10 wt% of solvent (N-methylpyrrolidone, NMP) were mixed with a planetary mixer (Thinky ARE-310) at 1,000 rpm for 15 minutes to prepare cathode slurry. The cathode slurry was applied to a PET film using an automatic coating machine and dried in a 120℃ drying oven for 30 minutes. The surface resistance of the dried cathode slurry film was measured using a surface resistance meter (NITTOSEIKO, Loresta-GS MCP-T700), and the electrode resistance was obtained by multiplying the measured surface resistance value by the electrode thickness.

[0130] 2. Results

[0131] Particle size (D50) [㎛] Viscosity [cps] Electrode resistance [Ω·cm] Example 11.89506.3 Example 21.38007.6 Example 31.07607.4 Example 41.58207.8 Example 51.410206.9 Example 61.15507.5 Example 71.67407.2 Example 81.77206.8 Example 90.61009.6 Example 102.212005.2 Example 114.224003.7 Example 121.611006.5 Example 131.49007.2 Example 141.26607.0 Example 151.614507.6 Embodiment 161.312007.1 Embodiment 171.29007.2 Embodiment 181.411006.6 Embodiment 191.511506.2 Embodiment 200.9909.2 Embodiment 212.716005.3 Embodiment 224.428003.4 Embodiment 231.69207.1 Embodiment 241.48406.9 Embodiment 251.27707.2 Embodiment 261.68307.2 Embodiment 271.411007.4 Embodiment 281.35807.2 Embodiment 291.38607.1 Embodiment 301.66706.7 Embodiment 310.71409.7 Example 322.98905.3 Example 335.319003.9 Example 341.210006.8 Example 351.59506.9 Example 361.47207.1 Example 371.212007.2 Example 381.711506.8 Example 391.610506.7 Example 401.812006.8 Example 411.210007.0 Example 420.41109.5 Example 432.114005.5 Example 444.725003.2 Example 453.612007.5 Example 463.812507.4 Embodiment 474.212007.0 Embodiment 484.114007.2 Embodiment 493.913506.8 Embodiment 504.412007.4 Embodiment 514.215007.2 Embodiment 523.914006.9 Embodiment 535.421004.4 Embodiment 545.528003.7 Embodiment 553.813007.1 Embodiment 563.512506.7 Embodiment 574.011807.2 Embodiment 584.015007.0 Embodiment 594.214006.7 Embodiment 604.112007.1 Embodiment 614.412507.0 Example 624.112007.2 Example 635.821004.6 Embodiment 645.226003.9 Embodiment 653.511006.4 Embodiment 663.412006.6 Embodiment 673.913006.7 Embodiment 684.412006.5 Embodiment 693.712506.8 Embodiment 704.711007.1 Embodiment 714.412006.9 Embodiment 723.313006.9 Embodiment 735.022004.2 Embodiment 745.226003.3 Embodiment 753.813006.2 Embodiment 763.912506.4 Embodiment 773.913006.6 Embodiment 784.211007.1Embodiment 793.913506.7Embodiment 804.214006.9Embodiment 813.813006.2Embodiment 823.712506.7Embodiment 835.420004.3Embodiment 845.527003.5Comparative Example 13.6530011.2Comparative Example 24.2720013.5Comparative Example 33.7600011.7Comparative Example 46.7400016.2Comparative Example 57.8320015.7Comparative Example 66.5430018.4.

[0132] As can be seen from Table 2 above, the carbon nanotube dispersions according to Comparative Examples 1 to 6 were found to have a viscosity of 3,000 cps or more and an electrode resistance of 10 Ωcm or more, whereas the carbon nanotube dispersions according to Examples 1 to 84 were found to have a viscosity of less than 3,000 cps and an electrode resistance of less than 10 Ωcm, confirming that the carbon nanotube dispersions according to the present invention have excellent dispersibility.

[0133] Therefore, when the carbon nanotube dispersion according to the present invention is used as a conductive material in the manufacture of a secondary battery electrode, it is expected that the performance as a conductive material can be maximized, thereby improving the conductivity of the secondary battery electrode and enhancing the performance of the secondary battery.

[0134]

[0135] While specific aspects of the present invention have been described in detail above, it should be apparent to those skilled in the art that these specific descriptions are merely preferred implementation examples and do not limit the scope of the present invention. Therefore, the substantial scope of the present invention is defined by the appended claims and their equivalents.

Claims

carbon nanotubes; Hydrogenated nitrile butadiene rubber as a first dispersant; 4-[4-[1,1-bis(4-hydroxyphenyl)ethyl]]-a,a-dimethylbenzylphenol as a second dispersant; alkaline additives; and menstruum; A carbon nanotube dispersion composition comprising: In the first paragraph, A carbon nanotube dispersion composition, characterized in that the carbon nanotubes are included in an amount of 2 to 20 wt% based on the total weight of the carbon nanotube dispersion composition. In the first paragraph, A carbon nanotube dispersion composition, characterized in that the hydrogenated nitrile butadiene rubber is included in an amount of 0.3 to 3.5 wt% based on the total weight of the carbon nanotube dispersion composition. In the first paragraph, A carbon nanotube dispersion composition, characterized in that the hydrogenated nitrile butadiene rubber is included in an amount of 15 to 25 wt% based on 100 wt% of carbon nanotubes. In the first paragraph, A carbon nanotube dispersion composition, characterized in that the above 4-[4-[1,1-bis(4-hydroxyphenyl)ethyl]]-a,a-dimethylbenzylphenol is contained in an amount of 0.5 to 5 wt% based on 100 wt% of carbon nanotubes. In the first paragraph, A carbon nanotube dispersion composition, characterized in that the second dispersant further comprises polyphenol. In paragraph 6, A carbon nanotube dispersion composition, characterized in that the second dispersant is included in an amount of 1 to 5 wt% based on 100 wt% of carbon nanotubes. In the first paragraph, A carbon nanotube dispersion composition, characterized in that the basic additive comprises N-methylethanolamine, ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, 2-amino-1-propanol, 3-amino-1-propanol, isopropanolamine, diisopropanolamine, triisopropanolamine, N-methylisopropanolamine, N-ethylisopropanolamine, N-propylisopropanolamine, or a combination thereof. In the first paragraph, A carbon nanotube dispersion composition, characterized in that the basic additive is included in an amount of 2 to 5.5 wt% based on 100 wt% of carbon nanotubes. In the first paragraph, A carbon nanotube dispersion composition, characterized in that the pH of the dispersion is 8 to 11. In the first paragraph, A carbon nanotube dispersion composition characterized in that the above carbon nanotube dispersion composition comprises 2 to 20 wt% of carbon nanotubes, 0.3 to 3.5 wt% of hydrogenated nitrile butadiene rubber, 0.5 to 5 wt% of 4-[4-[1,1-bis(4-hydroxyphenyl)ethyl]]-a,a-dimethylbenzylphenol, 2 to 5.5 wt% of an amine compound, and the remainder of a solvent. In the first paragraph, A carbon nanotube dispersion composition, characterized in that the average particle diameter (D50) of the carbon nanotube dispersion is 0.1 μm to 10 μm. In the first paragraph, A carbon nanotube dispersion composition, characterized in that the viscosity of the carbon nanotube dispersion under 25°C conditions is less than 3,000 cPs. A method for producing a carbon nanotube dispersion composition according to any one of claims 1 to 13, wherein the method comprises: A step of mixing a carbon nanotube dispersion composition comprising carbon nanotubes, hydrated nitrile butadiene rubber, 4-[4-[1,1-bis(4-hydroxyphenyl)ethyl]]-a,a-dimethylbenzylphenol, a basic additive, and a solvent; and A method for producing a carbon nanotube dispersion composition, comprising a step of dispersing the above carbon nanotube dispersion composition.

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