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KR-20260064841-A - NEGATIVE ELECTRODE ACTIVE MATERIAL, METHOD OF MANUFACTURING THE SAME AND LITHIUM SECONDARY BATTERY COMPRISING THE SAME

KR20260064841AKR 20260064841 AKR20260064841 AKR 20260064841AKR-20260064841-A

Abstract

A negative electrode active material according to one embodiment of the present invention comprises a silicon-carbon composite containing a plurality of silicon-based particles and a carbon body, wherein the carbon body comprises graphite, amorphous carbon, and a phosphorus (P) element, wherein the carbon body binds the different silicon-based particles, and the phosphorus (P) element forms a covalent bond with the carbon of the carbon body.

Inventors

  • 소비홍
  • 이가을
  • 장규연
  • 정지권

Assignees

  • (주)포스코퓨처엠

Dates

Publication Date
20260508
Application Date
20241029

Claims (19)

  1. It comprises a silicon-carbon composite containing a plurality of silicon-based particles and a carbon body, and The above carbon body comprises graphite, amorphous carbon, and phosphorus (P) element, and The above carbon body binds the different silicon-based particles together, The above phosphorus (P) element forms a covalent bond with the carbon of the above carbon body, a negative electrode active material.
  2. In paragraph 1, The above silicon-carbon composite has a first peak at 134.0±0.5 eV and a second peak at 132.0±0.5 eV in the P2p spectrum measured by X-ray Photoelectron Spectroscopy (XPS), A negative electrode active material in which the ratio of the area of the first peak to the area of the second peak is 1:0.04 to 0.10.
  3. In paragraph 2, The silicon-carbon composite further has a third peak at 130.5±0.5 eV in the P2p spectrum, A negative electrode active material in which the ratio of the area of the first peak to the area of the third peak is 1:0.025 to 0.080.
  4. In paragraph 1, The above carbon body further contains the element oxygen (O), and The above oxygen (O) element forms a covalent bond with the carbon of the above carbon body, a negative electrode active material.
  5. In paragraph 4, The above silicon-carbon composite has a fourth peak at 284.5±0.5 eV and a fifth peak at 289.0±0.5 eV in the C1s spectrum measured by X-ray Photoelectron Spectroscopy (XPS), A negative electrode active material in which the ratio of the area of the fourth peak to the area of the fifth peak is 1:0.10 to 0.50.
  6. In paragraph 1, The above amorphous carbon is included in an amount of 5 to 30 parts by weight based on 100 parts by weight of the silicon-based particles, in a negative electrode active material.
  7. In paragraph 1, The above graphite is a negative electrode active material comprising 75 to 250 parts by weight based on 100 parts by weight of the above amorphous carbon.
  8. In paragraph 1, A negative electrode active material in which the ratio of the average particle size (D50) of the silicon-based particles and the average particle size (D50) of the graphite is 1:2.0 to 5.0.
  9. In paragraph 1, The above silicon-based particles are a negative electrode active material comprising silicon (Si) particles.
  10. In paragraph 1, A negative electrode active material having an average Si crystal grain size of the silicon-based particles of the above-mentioned material of 20 to 50 nm.
  11. In paragraph 1, A negative electrode active material having an average particle size (D50) of the silicon-based particles of the above-mentioned material of 0.50 to 2.50 μm.
  12. In paragraph 1, A negative electrode active material having a specific surface area of 10.0 to 25.0 m²/g of the silicon-carbon composite.
  13. A step of obtaining a mixture by mixing silicon-based particles and a carbon precursor; A step of manufacturing an assembly by mixing graphite and an oxidizing agent into the above mixture; and The step of carbonizing the above assembly; A method for manufacturing a negative electrode active material in which the above oxidizing agent contains the element phosphorus (P).
  14. In Paragraph 13, A method for manufacturing a negative electrode active material , wherein the oxidizing agent comprises one or more selected from H₃PO₄ and P₂O₅ .
  15. In Paragraph 13, A method for manufacturing a negative electrode active material, wherein the graphite is mixed in an amount of 50 to 150 parts by weight based on 100 parts by weight of the carbon precursor.
  16. In Paragraph 13, A method for manufacturing a cathode active material, wherein, in the step of manufacturing the assembly, the mixture, the graphite, and the oxidizing agent are wet-mixed.
  17. In Paragraph 13, A method for manufacturing a negative electrode active material, wherein the silicon-based particles include silicon byproducts (Si dust) generated during the processing of a silicon wafer.
  18. In Paragraph 13, A method for manufacturing a negative electrode active material, wherein the carbon precursor comprises a pitch-based compound.
  19. cathode; Anode; and Contains electrolytes, A lithium secondary battery wherein the above-mentioned cathode comprises a cathode active material according to any one of claims 1 to 12.

Description

Negative electrode active material, method of manufacturing the same, and lithium secondary battery comprising the same The present invention relates to a negative electrode active material, a method for manufacturing the same, and a lithium secondary battery including the same. As the market for electronic devices such as mobile phones, laptops, and PCs grows, the market for lithium-ion batteries, their power source, is also expanding rapidly. Furthermore, as interest in environmental issues grows and the demand for eco-friendly vehicles like electric cars increases, there is a growing trend of research into lithium-ion batteries capable of meeting various applications. Among the components of a lithium-ion battery, the negative electrode active material stores lithium ions during charging and plays a crucial role in determining charging speed and battery capacity. Among these negative electrode active materials, silicon-based active materials are attracting attention because they possess higher capacity and superior fast charging characteristics compared to carbon-based active materials. However, silicon-based active materials have somewhat low structural stability, and because the degree of volume expansion and contraction during charging and discharging is large, there was a problem in that silicon-based particles became finely pulverized or the battery life characteristics deteriorated. Accordingly, there is a need to develop cathode active materials that can minimize problems caused by volume expansion and contraction. Figure 1 is a scanning electron microscope (SEM) image of the negative electrode active material of Example 1 and Comparative Examples 1 to 3. Preferred embodiments of the present invention are described below. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. In addition, embodiments of the present invention are provided to more fully explain the present invention to those with average knowledge in the relevant technical field. In describing the embodiments of the present invention, if it is determined that a detailed description of known technology related to the present invention may unnecessarily obscure the essence of the present invention, such detailed description will be omitted. Furthermore, the terms described below are defined considering their functions in the present invention, and these may vary depending on the intentions or conventions of the user or operator. Therefore, such definitions should be based on the content throughout this specification. The terms used in the detailed description are merely for describing the embodiments of the present invention and should not be limited in any way. Unless explicitly stated otherwise, expressions in the singular form include the meaning of the plural form. In this description, expressions such as “include” or “equipped” are intended to refer to certain characteristics, numbers, steps, actions, elements, parts or combinations thereof, and should not be interpreted to exclude the existence or possibility of one or more other characteristics, numbers, steps, actions, elements, parts or combinations thereof other than those described. Unless otherwise specifically defined in the specification of the present invention, % units mean weight %. The present invention will be described in detail below through each embodiment or example of the invention. It should be noted that each embodiment or example described in this specification is not limited to a single embodiment or example, but may also be combined with other embodiments or examples. Accordingly, the citation of claims in the patent claims is merely an example of an embodiment, and the technical concept of the present invention should not be interpreted as being limited only to a combination with the cited claims; rather, combinations with various claims are also included within the scope of the technical concept of the present invention. A negative electrode active material is provided according to one embodiment of the present invention. The negative electrode active material according to one embodiment of the present invention comprises a silicon-carbon composite containing a plurality of silicon-based particles and a carbon body, wherein the carbon body comprises graphite, amorphous carbon, and a phosphorus (P) element, wherein the carbon body binds the different silicon-based particles together, and the phosphorus (P) element forms a covalent bond with the carbon of the carbon body. Specifically, the carbon body binds different silicon-based particles together and provides structural stability to the silicon-carbon composite. The carbon body can be filled between the silicon-based particles and positioned to surround their surfaces. In this case, the carbon body acts as a binder between the silicon-based particles, thereby maintaining the structura