Search

KR-20260065240-A - CARBON NANOTUBE DISPERSED SOLUTION AND METHOD FOR PREPARING THE SAME

KR20260065240AKR 20260065240 AKR20260065240 AKR 20260065240AKR-20260065240-A

Abstract

The present invention relates to a carbon nanotube dispersion and a method for preparing the same, comprising a conductive material, a dispersant, and a dispersion medium, wherein the conductive material comprises porous carbon particles and carbon nanotubes, and the dispersant comprises a main dispersant comprising hydrogenated nitrile butadiene rubber; and an auxiliary dispersant comprising a polyether-based polymer. The carbon nanotube dispersion has the characteristic of having a small change in viscosity over time as carbon nanotubes are uniformly and effectively dispersed.

Inventors

  • 장지혜
  • 김기영
  • 이민기
  • 박기선

Assignees

  • 주식회사 엘지화학

Dates

Publication Date
20260508
Application Date
20241101

Claims (13)

  1. It includes a conductive agent, a dispersant, and a dispersion medium, The above conductive material comprises porous carbon particles and carbon nanotubes, and The above dispersant comprises a main dispersant comprising hydrogenated nitrile butadiene rubber; and A carbon nanotube dispersion comprising an auxiliary dispersant comprising a polyether-based polymer.
  2. In claim 1, A carbon nanotube dispersion characterized in that the conductive material is included in the carbon nanotube dispersion in an amount of 1% to 10% by weight based on the total weight of the carbon nanotube dispersion.
  3. In claim 1, A carbon nanotube dispersion characterized in that the above-mentioned porous carbon particles are included in the carbon nanotube dispersion in an amount of 1 to 30 parts by weight based on 100 parts by weight of conductive material.
  4. In claim 1, A carbon nanotube dispersion characterized in that the porous carbon particles have an average particle size (D 50 ) of 1.0 μm to 5.0 μm and a BET specific surface area of 10 m² /g to 700 m² /g.
  5. In claim 1, A carbon nanotube dispersion characterized by containing 20 to 99 parts by weight of the carbon nanotubes based on 10 parts by weight of porous carbon particles.
  6. In claim 1, A carbon nanotube dispersion characterized in that the above-mentioned dispersant is included in the carbon nanotube dispersion in an amount of 0.1% to 5% by weight based on the total weight of the carbon nanotube dispersion.
  7. In claim 1, A carbon nanotube dispersion characterized in that the above-mentioned dispersant is included in the carbon nanotube dispersion in an amount of 10 to 40 parts by weight based on 100 parts by weight of conductive material.
  8. In claim 1, A carbon nanotube dispersion characterized by the above polyether-based polymer comprising repeating units derived from C2 to C8 alkylene oxide.
  9. In claim 1, A carbon nanotube dispersion characterized by the above-mentioned dispersant containing a main dispersant and an auxiliary dispersant in a weight ratio of 2:1 to 5:1.
  10. A method for preparing a carbon nanotube dispersion according to claim 1, (1) A step of preparing a carbon nanotube premixed dispersion by mixing a conductive material, a dispersant, and a dispersion medium; and (2) A step of producing a carbon nanotube dispersion by high-pressure homogenizing the carbon nanotube premixed dispersion using a high-pressure homogenizer; comprising a method for producing a carbon nanotube dispersion.
  11. In claim 10, The above (2) step is characterized by performing high-pressure homogenization under a pressure of 100 bar to 3,000 bar, in a method for preparing a carbon nanotube dispersion.
  12. In claim 10, A method for preparing a carbon nanotube dispersion, characterized by performing high-pressure homogenization 1 to 7 times in step (2) above.
  13. An electrode slurry composition comprising a carbon nanotube dispersion according to claim 1, an electrode active material, a binder, and a solvent.

Description

Carbon nanotube dispersed solution and method for preparing the same The present invention relates to a carbon nanotube dispersion and a method for preparing the same. Specifically, the invention relates to a carbon nanotube dispersion comprising a conductive material including porous carbon particles and carbon nanotubes, a dispersant including a main dispersant including hydrogenated nitrile butadiene rubber and an auxiliary dispersant including a polyether-based polymer, and a dispersion medium, and a method for preparing the same. With the increasing technological development and demand for mobile devices, the demand for secondary batteries as an energy source is rapidly rising. Among these secondary batteries, lithium-ion batteries, which possess high energy density and voltage, long cycle life, and low self-discharge rates, have been commercialized and are widely used. Furthermore, active research is being conducted on methods to manufacture electrodes for such high-capacity lithium-ion batteries by improving electrode density to achieve higher energy density per unit volume. Generally, high-density electrodes are formed by molding electrode active material particles with a size of several micrometers to tens of micrometers using a high-pressure press. However, during the molding process, the particles may be deformed and the space between the particles may be reduced, which can easily lead to a decrease in electrolyte penetration. To solve the above problems, conductive materials with excellent electrical conductivity and strength are used during the manufacture of electrodes. Even when the conductive material is positioned between the electrode active materials and undergoes the molding process, it maintains the micropores between the active material particles, allowing the electrolyte to penetrate easily, and has excellent electrical conductivity, which can reduce resistance within the electrode. Among such conductive materials, the use of carbon nanotubes, which are fibrous carbon-based conductive materials capable of further reducing electrode resistance by forming electrical conduction paths within the electrode, is increasing. The carbon nanotubes mentioned above are fine carbon fibers in which carbons connected by hexagonal rings form a long tube-shaped structure with a diameter of 1 μm or less. Due to the high conductivity, tensile strength, and heat resistance resulting from the unique structure of the carbon nanotubes, their application and commercialization in various fields are anticipated. For the commercialization of the carbon nanotubes as conductive materials, it is necessary to manufacture them in a dispersion state rather than in powder form. However, due to the strong agglomeration of the carbon nanotubes, it is difficult to lower the viscosity when manufactured as a dispersion, and even if the viscosity is lowered, it increases over time, posing a problem that makes it difficult to apply in actual processes. To address these issues, methods have been proposed to disperse carbon nanotubes in a dispersion medium using mechanical dispersion treatments such as ultrasonic treatment. However, mechanical dispersion methods present problems, such as carbon nanotubes aggregating immediately upon the termination of ultrasonic irradiation or re-aggregating over time after dispersion. When carbon nanotubes aggregate, the coating properties deteriorate during the process, or it becomes difficult to obtain products with a uniform thickness. Therefore, the relevant technical field requires a technology for manufacturing a carbon nanotube dispersion with improved carbon nanotube dispersibility. The inventors completed the present invention after continuous research on conductive materials and dispersants as a solution to the aforementioned problems regarding carbon nanotube dispersions. All embodiments provided according to the present invention can be achieved by the following description. It should be understood that the following description describes preferred embodiments of the present invention and that the present invention is not necessarily limited thereto. Where measurement conditions and methods are not specifically described for the physical properties described in this specification, said physical properties are measured according to measurement conditions and methods generally used by a person skilled in the art. In this specification, the average particle size (D 50 ) refers to a particle size corresponding to 50% of the volume accumulation. The D 50 can be measured, for example, using a laser diffraction method. The laser diffraction method generally enables the measurement of particle sizes ranging from the submicron region to several mm, and can obtain results with high reproducibility and high resolution. In this specification, "BET specific surface area" is measured by the BET method (Brunauer-Emmett-Teller Analysis), and specifically, can be calculated from the amount of nitr