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KR-102963846-B1 - ANODE ACTIVE MATERIAL FOR LITHIUM SECONDARY BATTERY, METHOD OF MANUFACTURING THEREOF, AND LITHIUM SECONDARY BATTERY COMPRISING SAME

KR102963846B1KR 102963846 B1KR102963846 B1KR 102963846B1KR-102963846-B1

Abstract

The present embodiments relate to a negative electrode active material for a lithium secondary battery, a method for manufacturing the same, and a lithium secondary battery including the same. The negative electrode active material of the present invention comprises coarse carbon particles and fine carbon particles and satisfies Formula 1 below. <Equation 1> 0.45 ≤ tap density (g/cc)/BET specific surface area ( m² /g) ≤ 0.72

Inventors

  • 김대식
  • 권성상
  • 김가은
  • 연선영
  • 장영훈

Assignees

  • (주)포스코퓨처엠

Dates

Publication Date
20260511
Application Date
20231027

Claims (17)

  1. Coarse carbon particles having an average particle size (D50) of 8 to 15 μm and 7 μm It includes fine carbon particles having an average particle size (D50) of less than or equal to, A negative electrode active material for a lithium secondary battery satisfying Formula 1 below. <Equation 1> 0.45 ≤ tap density (g/cc)/BET specific surface area ( m² /g) ≤ 0.72
  2. In Article 1, A negative electrode active material for a lithium secondary battery satisfying the following Equation 2. <Equation 2> 9.50 ≤ (I(004)/I(110))/(D90-D10) ≤ 15.00 (In Equation 2 above, I(004) and I(110) are the intensities of the XRD peak values of the 004 plane and 110 plane, respectively, and D10 and D90 represent the particle sizes when the cathode active material particles, which have various particle sizes distributed, are accumulated up to 10% and 90% by volume ratio, respectively.)
  3. In Article 1, A negative electrode active material for a lithium secondary battery, wherein the weight of the fine carbon particles is 5 to 30 weight percent relative to the total amount of the coarse carbon particles and the fine carbon particles.
  4. In Article 1, A negative electrode active material for a lithium secondary battery in which, among the values of voltage values measured according to SOC %, the point at which an inflection point appears is SOC 30% or higher.
  5. In Article 1, A negative electrode active material for a lithium secondary battery satisfying the following Equation 3. <Equation 3> 0.65 ≤ ([SOC 50 %] - [SOC 20 %])/[SOC 20 %] ≤ 2.00 (In Equation 3 above, [SOC 20%] and [SOC 50%] represent the average voltage values when the SOC is 20% and 50%, respectively.)
  6. In Article 1, The above coarse carbon particles and the above fine carbon particles are negative electrode active materials for lithium secondary batteries, which are artificial graphite, natural graphite, or a combination thereof.
  7. In Article 1, A negative electrode active material for a lithium secondary battery having an average particle size (D50) of 8.0 to 20.0 μm.
  8. In Article 1, A negative electrode active material for a lithium secondary battery having a specific surface area (BET) of 1.15 m² /g or more.
  9. In Article 1, Negative electrode active material for a lithium secondary battery having a tap density of 0.82 g/cc or less.
  10. In Article 1, A negative electrode active material having an orientation (I 004 /I 001 ) of 1.85 or less. (The above I 004 and I 001 represent the peak intensity ratios of planes (004) and (001), respectively.)
  11. A negative electrode for a lithium secondary battery comprising 96 to 99 wt% of a negative electrode active material according to any one of claims 1 to 10, 0.5 to 1.5 wt% of a thickener, and the remainder being a binder; Anode comprising a positive electrode active material; and A lithium secondary battery containing an electrolyte.
  12. At least one coarse carbon particle having an average particle size (D50) of 8 to 15 μm and 7 μm A step of preparing at least one fine carbon particle having an average particle size (D50) of less than or equal to the average particle size; A step of assembling and carbonizing the above coarse carbon particles and the above fine carbon particles; Step of graphitizing the carbonized assembly; and The method includes the step of coating a graphitized graphitized product, and In the step of assembling and carbonizing the above coarse carbon particles and the above fine carbon particles A method for manufacturing a negative electrode active material for a lithium secondary battery, comprising the step of mixing the fine carbon particles in an amount of 5 to 30 weight% based on the total amount of the coarse carbon particles and the fine carbon particles.
  13. In Article 12, In the step of assembling and carbonizing the above coarse carbon particles and the above fine carbon particles, A method for manufacturing a negative electrode active material for a lithium secondary battery, wherein the content of the coating material is mixed in an amount of 3 to 30 parts by weight based on 100 parts by weight of the total amount of the coarse carbon particles and the fine carbon particles.
  14. In Article 12, A method for manufacturing a negative electrode active material for a lithium secondary battery, wherein the above-mentioned coarse carbon particles and above-mentioned fine carbon particles are coal-based needle calcination, needle green, isotropic calcination, isotropic green, petroleum-based needle calcination, needle green, general calcination, general green, or a combination thereof.
  15. In Article 12, At least one coarse carbon particle having an average particle size (D50) of 8 to 15 μm and 7 μm In the step of preparing at least one fine carbon particle having an average particle size (D50) of less than or equal to, A method for manufacturing a negative electrode active material for a lithium secondary battery, comprising the step of grinding the above coarse carbon particles to have a particle size of 8 to 15 μm.
  16. In Article 12, The step of coating the above graphitized graphitized product is A method for manufacturing a negative electrode active material for a lithium secondary battery, comprising the step of mixing a coating material in an amount of 1 to 5 parts by weight based on the above graphitized product.
  17. In Article 12, A method for manufacturing a cathode active material in which the step of graphitizing the above carbonized assembly is performed in a temperature range of 2,800 ℃ or higher.

Description

Anode active material for lithium secondary battery, method of manufacturing the same, and lithium secondary battery comprising the same The present embodiments relate to lithium secondary batteries, and more specifically, to a negative electrode active material for a lithium secondary battery, a method for manufacturing the same, and a lithium secondary battery including the same. Social concern is mounting regarding the depletion of fossil fuels and the environmental pollution caused by their use, and eco-friendly energy sources are garnering attention as a solution. Among these eco-friendly energy sources, interest in electric energy is increasing, and in particular, lithium-ion batteries are receiving significant attention. The application scope of lithium-ion batteries is expanding beyond small electronic devices and portable IT equipment to include electric vehicles and energy storage systems. With this expansion of application, the development of new materials for high capacity and high output is becoming increasingly important. Among the components of the lithium-ion battery, the negative electrode plays the role of storing lithium ions and is a key factor related to the battery's capacity and lifespan. Various forms of carbon-based materials, including artificial graphite, natural graphite, and hard carbon, which allow for the insertion/extraction of lithium, have been applied as the above-mentioned cathode material. Since graphite has a discharge voltage of 0.2 V lower than that of lithium, batteries using graphite as the cathode active material exhibit a high discharge voltage of 3.6 V, providing an advantage in terms of energy density of lithium secondary batteries. In addition, it is the most widely used material as it ensures a long lifespan of lithium secondary batteries due to its excellent reversibility. The above-mentioned natural graphite has the advantage of being highly effective as a cathode material because it is inexpensive and exhibits electrochemical properties similar to artificial graphite. However, natural graphite has a plate-like shape, so it has a large surface area and its edges are exposed, which causes problems such as electrolyte penetration or decomposition reactions when applied as a cathode active material. Consequently, the edges may peel off or break, leading to significant irreversible reactions. Furthermore, when manufactured into an electrode plate, the graphite material is compressed and oriented flatly on the current collector, making it difficult to impregnate the electrolyte and thus degrading charge/discharge characteristics. To address this, efforts are being made to transform natural graphite into a smooth surface shape through post-processing, such as spheroidization, to reduce irreversible reactions and improve the processability of the electrode. The graphite commercially available as the anode material exhibits excellent lifespan characteristics and high theoretical capacity because there is little change in the crystal structure during the insertion and extraction of lithium ions, allowing oxidation and reduction reactions to occur continuously. However, since the graphite can only accommodate one lithium ion per six carbon atoms, it can secure a limited theoretical capacity, for example, of about 372 mAh/g, which presents limitations in meeting the requirements for high power and high capacity. In addition, the mobility of lithium ions is generally very low in the solid compared to the diffusion rate in the electrolyte. In this case, to increase the mobility of the lithium ions, the smaller the particle size, the shorter the diffusion distance in the solid, which is advantageous for charging, specifically rapid charging. As such, research on methods to utilize finely ground products with small particle sizes is continuing. FIG. 1 illustrates a negative electrode active material for a lithium secondary battery according to one embodiment of the present invention. FIG. 2 is a flowchart relating to a method for manufacturing a negative electrode active material for a lithium secondary battery according to one embodiment of the present invention. FIGS. 3a to 3c are micrographs of negative electrode active materials for lithium secondary batteries according to embodiments and comparative examples of the present invention. FIGS. 4a to 4c are micrographs of negative electrode active materials for lithium secondary batteries according to embodiments and comparative examples of the present invention. Terms such as first, second, and third are used to describe various parts, components, regions, layers, and/or sections, but are not limited thereto. These terms are used solely to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Accordingly, the first part, component, region, layer, or section described below may be referred to as the second part, component, region, layer, or section without depar