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CN-121983523-A - Negative electrode material, preparation method thereof, negative electrode plate, battery pack and electric equipment

CN121983523ACN 121983523 ACN121983523 ACN 121983523ACN-121983523-A

Abstract

The embodiment of the invention provides a negative electrode material, a preparation method thereof, a negative electrode plate, a battery pack and electric equipment. The anode material comprises a porous carbon matrix, a first intermediate layer and a silicon layer, wherein the first intermediate layer is coated on at least part of the surface of the porous carbon matrix, the silicon layer is coated on at least part of the surface of the first intermediate layer, and the first intermediate layer comprises SiN x , wherein x is 0< 4/3. The anode material has better transmission efficiency of active metal ions, and can improve the first charge and discharge efficiency, the rate capability and the capacity retention rate of the battery.

Inventors

  • YAN ZHILIN
  • LI SHAOJIE
  • DU QUAN
  • LIU ZHAOBO
  • XU CHAQING

Assignees

  • 比亚迪股份有限公司

Dates

Publication Date
20260505
Application Date
20250805

Claims (15)

  1. 1. The negative electrode material is characterized by comprising a porous carbon matrix, a first middle layer and a silicon layer; The first intermediate layer is coated on at least part of the surface of the porous carbon matrix; The silicon layer is coated on at least part of the surface of the first intermediate layer; The first intermediate layer comprises SiN x , 0< x <4/3.
  2. 2. The negative electrode material according to claim 1, wherein the porous carbon matrix comprises N element, and the mass ratio of the N element in the porous carbon matrix is 5-30 wt%.
  3. 3. The anode material according to claim 1 or 2, wherein the first intermediate layer further comprises Si 3 N 4 .
  4. 4. A negative electrode material according to claim 3, characterized in that the mass percentage of Si 3 N 4 in the first intermediate layer is not more than 50%, preferably not more than 5%.
  5. 5. The anode material according to claim 1 or 2, wherein the pore diameter of the pores in the porous carbon matrix ranges from 0.6nm to 5nm; and/or the thickness ratio of the first intermediate layer to the porous carbon matrix is 0.1% -1%; And/or the thickness ratio of the silicon layer to the first intermediate layer is (0.2-1): 1.
  6. 6. The negative electrode material according to any one of claims 1 to 5, wherein at least part of the surface of the silicon layer of the negative electrode material is further provided with a carbon coating layer, and the thickness ratio of the carbon coating layer to the first intermediate layer is (1 to 2): 1.
  7. 7. The anode material according to claim 6, wherein a second intermediate layer is further provided between the carbon coating layer and the silicon layer, and the second intermediate layer is coated on at least part of the surface of the silicon layer; wherein the second intermediate layer comprises SiN x , 0< x <4/3; And/or the thickness ratio of the carbon coating layer to the second intermediate layer is (1-2): 1.
  8. 8. The anode material according to claim 6 or 7, wherein the carbon coating layer is further doped with N element, and the mass ratio of the N element in the carbon coating layer is 5wt% to 30wt%.
  9. 9. The anode material according to claim 7, wherein the thickness of the first intermediate layer is 0.5nm to 5nm; And/or the thickness of the silicon layer is 0.5 nm-5 nm; and/or the thickness of the second intermediate layer is 0.5 nm-5 nm; And/or the thickness of the carbon coating layer is 1 nm-5 nm.
  10. 10. A method for producing the anode material according to any one of claims 1 to 9, comprising the steps of: 1) Placing a porous carbon matrix in first raw material gas for first vapor deposition to obtain an intermediate coating product; The first raw material gas comprises a silicon source and a nitrogen source, wherein the volume ratio of the silicon source to the nitrogen source is 1 (0.01-1); 2) Placing the intermediate coating product in a second raw gas for second vapor deposition to obtain the anode material; the second feed gas includes a silicon source.
  11. 11. The method for preparing a negative electrode material according to claim 10, wherein the deposition temperature of the first vapor deposition is 450 ℃ to 600 ℃ and the deposition time is 0.1h to 2h; And/or the deposition temperature of the second vapor deposition is 450-600 ℃ and the deposition time is 1-10 h.
  12. 12. A negative electrode sheet comprising the negative electrode material according to any one of claims 1 to 9, or the negative electrode material produced by the method for producing a negative electrode material according to claim 10 or 11.
  13. 13. A battery comprising the negative electrode material according to any one of claims 1 to 9 or the negative electrode sheet according to claim 12.
  14. 14. A battery comprising the anode material of any one of claims 1-9 or at least two of the cells of claim 13.
  15. 15. A powered device comprising the negative electrode material of any one of claims 1-9, or the battery of claim 13, or the battery pack of claim 14.

Description

Negative electrode material, preparation method thereof, negative electrode plate, battery pack and electric equipment Technical Field The invention relates to the technical field of batteries, in particular to a negative electrode material, a preparation method thereof, a negative electrode plate, a battery pack and electric equipment. Background The secondary battery has higher energy density and longer service life, and is widely applied to various electric equipment. With the increasing demand of modern technologies for various electric devices, a negative electrode material with high energy density needs to be used so that a battery can adapt to long-time electricity demand. The silicon carbon material is a common cathode material of the secondary battery and has higher specific capacity. However, the battery using the silicon carbon material as the negative electrode material has problems of low first charge-discharge efficiency, rate capability and capacity retention. Therefore, a silicon-carbon negative electrode material is needed to improve the first charge-discharge efficiency, the rate capability and the capacity retention rate of the battery. Disclosure of Invention The invention provides a negative electrode material and a preparation method thereof, a negative electrode plate, a battery pack and electric equipment, the anode material has better transmission efficiency of active metal ions, and can improve the first charge and discharge efficiency, the rate capability and the capacity retention rate of the battery. The embodiment of the invention provides a cathode material which comprises a porous carbon matrix, a first middle layer and a silicon layer; The first intermediate layer is coated on at least part of the surface of the porous carbon matrix; The silicon layer is coated on at least part of the surface of the first intermediate layer; The first intermediate layer comprises SiN x, 0< x <4/3. According to some embodiments of the invention, the porous carbon matrix comprises N element, and the mass ratio of the N element in the porous carbon matrix is 5-30wt%. In some embodiments of the invention, the first interlayer further comprises Si 3N4, In some embodiments of the present invention, the Si 3N4 is present in the first interlayer in an amount of no more than 50% by mass, preferably no more than 5% by mass. According to some embodiments of the invention, the pore diameter of the pores in the porous carbon matrix ranges from 0.6nm to 5nm; and/or the thickness ratio of the first intermediate layer to the porous carbon matrix is 0.1% -1%; And/or the thickness ratio of the silicon layer to the first intermediate layer is (0.2-1): 1. According to some embodiments of the invention, at least part of the surface of the silicon layer of the anode material is further provided with a carbon coating layer, and the thickness ratio of the carbon coating layer to the first intermediate layer is (1-2): 1. According to some embodiments of the invention, a second intermediate layer is further arranged between the carbon coating layer and the silicon layer, and the second intermediate layer is coated on at least part of the surface of the silicon layer; wherein the second intermediate layer comprises SiN x, 0< x <4/3; And/or the thickness ratio of the carbon coating layer to the second intermediate layer is (1-2): 1. According to some embodiments of the invention, the carbon coating layer is further doped with N element, and the mass ratio of the N element in the carbon coating layer is 5-30 wt%. According to some embodiments of the invention, the thickness of the first intermediate layer is 0.5 nm-5 nm; And/or the thickness of the silicon layer is 0.5 nm-5 nm; and/or the thickness of the second intermediate layer is 0.5 nm-5 nm; And/or the thickness of the carbon coating layer is 1 nm-5 nm. The embodiment of the invention also provides a preparation method of the anode material, which comprises the following steps: 1) Placing a porous carbon matrix in first raw material gas for first vapor deposition to obtain an intermediate coating product; The first raw material gas comprises a silicon source and a nitrogen source, wherein the volume ratio of the silicon source to the nitrogen source is 1 (0.01-1); 2) Placing the intermediate coating product in a second raw gas for second vapor deposition to obtain the anode material; the second feed gas includes a silicon source. In some embodiments of the present invention, the deposition temperature of the first vapor deposition is 450 ℃ to 600 ℃ and the deposition time is 0.1h to 2h; and/or the deposition temperature of the second vapor deposition is 450-600 ℃ and the deposition time is 1-10 h; The embodiment of the invention also provides a negative electrode plate, which comprises the negative electrode material or the negative electrode material prepared by the preparation method of the negative electrode material. The embodiment of the invention also provide