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KR-102963848-B1 - ANODE ACTIVE MATERIAL FOR LITHIUM RECHARGEABLE BATTERY, MANUFACTURING METHOD OF THE SAME AND LITHIUM RECHARGEABLE BATTERY COMPRISING THE SAME

KR102963848B1KR 102963848 B1KR102963848 B1KR 102963848B1KR-102963848-B1

Abstract

The present invention relates to a negative electrode active material for a lithium secondary battery comprising graphite particles; silicon-based active material particles; and an amorphous carbon material, wherein the crystallite size (Lc) in the c-axis direction of the graphite particles is 18 to 31 nm, the average Raman peak intensity ratio (I D / I G ) of the amorphous carbon material is 0.3 to 1.0, and the standard deviation of the Raman peak intensity ratio (I D / I G ) of the amorphous carbon material is 0.1 or less.

Inventors

  • 안정철
  • 박세민
  • 이강호
  • 조현철
  • 조문규
  • 양인찬
  • 최선희

Assignees

  • 재단법인 포항산업과학연구원

Dates

Publication Date
20260512
Application Date
20231222

Claims (20)

  1. A composite negative electrode active material comprising graphite particles; silicon-based active material particles; and an amorphous carbon material, The crystallite size (Lc) in the c-axis direction of the graphite particles is 18 to 29 nm, the average Raman peak intensity ratio (I D / I G ) of the amorphous carbon material is 0.3 to 1.0, and the standard deviation of the Raman peak intensity ratio (I D / I G ) of the amorphous carbon material is 0.1 or less. A negative electrode active material for a lithium secondary battery, wherein the crystallite size (La) in the a-axis direction of the graphite particles is 35 to 57 nm.
  2. In paragraph 1, The above composite negative electrode active material is a negative electrode active material for a lithium secondary battery in the form of secondary particles in which a plurality of graphite particles and a plurality of silicon-based active material particles are dispersed and aggregated within a matrix of the above amorphous carbon material.
  3. delete
  4. In paragraph 1, A negative electrode active material for a lithium secondary battery, wherein the degree of sphericity of the graphite particles is 0.6 to 0.83.
  5. In paragraph 1, The above graphite particles are waste graphite particles, which are negative electrode active materials for lithium secondary batteries.
  6. In paragraph 1, A negative electrode active material for a lithium secondary battery having a carbon content of 95 weight% or more of the graphite particles.
  7. In paragraph 1, A negative electrode active material for a lithium secondary battery, wherein the average particle size (D50) of the graphite particles is 5 to 15 μm.
  8. In paragraph 1, The silicon-based active material particles are silicon microparticles, silicon oxide, or a combination thereof, and are negative electrode active materials for lithium secondary batteries.
  9. In paragraph 1, A negative electrode active material for a lithium secondary battery, wherein the content of the silicon-based active material particles is 2 to 20 weight% based on the total weight of the graphite particles.
  10. In paragraph 1, A negative electrode active material for a lithium secondary battery, wherein the average particle size (D50) of the above composite negative electrode active material is 3 to 30 μm.
  11. In paragraph 1, The above amorphous carbon material is a negative electrode active material for a lithium secondary battery, which is soft carbon, hard carbon, or a combination thereof.
  12. A step of forming a mixture comprising graphite powder having a crystallite size (Lc) in the c-axis direction of 18 to 29 nm and a crystallite size (La) in the a-axis direction of 35 to 57 nm, silicon-based active material powder, and a binder having a quinoline insoluble content of 20 wt% or less and a toluene insoluble content of 50 wt% or less; A step of carbonizing the above mixture at a temperature of 600 to 1000°C to form a carbonized product; and A method for manufacturing a negative electrode active material for a lithium secondary battery, comprising the step of breaking down the above-mentioned carbide to form a composite negative electrode active material.
  13. In Paragraph 12, In the step of forming the above mixture, A method for manufacturing a negative electrode active material for a lithium secondary battery, wherein the degree of sphericity of the graphite powder is 0.6 to 0.83.
  14. In Paragraph 12, In the step of forming the above mixture, A method for manufacturing a negative electrode active material for a lithium secondary battery, wherein the graphite powder above is waste graphite powder.
  15. In Paragraph 12, In the step of forming the above mixture, A method for manufacturing a negative electrode active material for a lithium secondary battery, wherein the binder is coal tar, coal-based pitch, petroleum-based pitch, mesophase pitch, coal-based heavy oil, petroleum-based heavy oil, coal-based light oil, petroleum-based light oil, coke, or a combination thereof.
  16. In Paragraph 12, In the step of forming the above mixture, A method for manufacturing a negative electrode active material for a lithium secondary battery, wherein the softening point of the binder is 15 to 120°C.
  17. In Paragraph 12, In the step of forming the above mixture, A method for manufacturing a negative electrode active material for a lithium secondary battery, wherein the quinoline-insoluble content of the binder is 18% by weight or less.
  18. In Paragraph 12, In the step of forming the above mixture, A method for manufacturing a negative electrode active material for a lithium secondary battery, wherein the toluene-insoluble content of the binder is 48% by weight or less.
  19. In Paragraph 12, In the step of forming the above mixture, A method for manufacturing a negative electrode active material for a lithium secondary battery, wherein the content of the binder is 5 to 20 weight percent based on the total weight of the mixture.
  20. In Paragraph 12, In the step of forming the above composite cathode active material, A method for manufacturing a negative electrode active material for a lithium secondary battery, wherein the above-mentioned disintegration is performed so that the composite negative electrode active material has an average particle size (D50) of 3 to 30 μm.

Description

Anode active material for lithium rechargeable battery, manufacturing method of the same, and lithium rechargeable battery comprising the same The present invention relates 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. More specifically, the invention relates to a negative electrode active material for a lithium secondary battery utilizing (waste) graphite, a method for manufacturing the same, and a lithium secondary battery including the same. Recently, interest in energy storage technology has been steadily increasing. As application fields expand to include mobile phones, camcorders, laptop PCs, and even electric vehicles, there is a growing demand for higher energy density in the batteries used as power sources for these electronic devices. Lithium-ion batteries are the type of battery best suited to meet these demands, and active research is currently underway in this area. Such lithium secondary batteries generally include a positive electrode made of lithium metal oxide, a negative electrode made of carbon material, an electrolyte containing a lithium salt and an organic solvent, and a separator interposed between the positive electrode and the negative electrode to electrically insulate them. Generally, a negative electrode for a lithium secondary battery is manufactured by mixing a negative electrode active material, a conductive material, and a binder to form a slurry, coating it onto a current collector, and then drying and rolling it. As a negative electrode active material, the use of carbon-based active materials that enable reversible lithium ion intercalation and extraction while maintaining structural and electrical properties is emerging. Various forms of carbon-based materials, including artificial graphite, natural graphite, and hard carbon, have been applied as such carbon-based active materials. Among these, graphite-based active materials are the most widely used because they can guarantee the lifespan characteristics of lithium secondary batteries through excellent reversibility. Meanwhile, as the demand for lithium-ion batteries increases, there is a need for a smooth supply of graphite-based active materials. To reduce costs, there is a demand for the development of technology capable of producing high-quality anode active materials using waste graphite generated during the battery manufacturing process as a raw material. However, compared to commercial graphite, waste graphite has inferior physical properties such as crystallite size in the c-axis direction or sphericity, leading to a problem of degraded electrochemical characteristics, including capacity. 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 departing from the scope of the present invention. The technical terms used herein are for the reference of specific embodiments only and are not intended to limit the invention. The singular forms used herein include plural forms unless phrases clearly indicate otherwise. As used in the specification, the meaning of "comprising" specifies certain characteristics, areas, integers, steps, actions, elements, and/or components, and does not exclude the presence or addition of other characteristics, areas, integers, steps, actions, elements, and/or components. When it is stated that one part is "above" or "on" another part, it may be directly above or on the other part, or other parts may be involved in between. In contrast, when it is stated that one part is "directly above" another part, no other parts are interposed in between. Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as generally understood by those skilled in the art to which this invention pertains. Terms defined in commonly used dictionaries are further interpreted to have meanings consistent with relevant technical literature and the present disclosure, and are not interpreted in an ideal or highly formal sense unless otherwise defined. Also, unless otherwise specified, % means weight %, and 1 ppm is 0.0001 weight %. In this specification, the term “combination(s) of these” described in the Markush-type expression means one or more mixtures or combinations selected from the group consisting of the components described in the Markush-type expression, and means including any one or more selected from the group consisting of said components. Hereinafter, embodiments of the present invention are described in detail so that those skilled in