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CN-121983526-A - Silicon-carbon material, negative plate, battery pack and electronic equipment

CN121983526ACN 121983526 ACN121983526 ACN 121983526ACN-121983526-A

Abstract

The invention provides a silicon-carbon material, a negative plate, a battery pack and electronic equipment. The silicon-carbon material comprises a silicon-carbon matrix and a protruding structure protruding out of the surface of the silicon-carbon matrix, wherein the protruding structure comprises metal oxide and/or metal lithium salt. When the silicon-carbon material is applied to a battery, the cycle performance of the battery can be improved.

Inventors

  • CHENG XIANGNAN
  • JIANG FULIN
  • LI SHUNCHANG
  • LIU ZHAOBO
  • XU CHAQING

Assignees

  • 比亚迪股份有限公司

Dates

Publication Date
20260505
Application Date
20250925

Claims (18)

  1. 1. The silicon-carbon material is characterized by comprising a silicon-carbon matrix and a convex structure protruding out of the surface of the silicon-carbon matrix; The bump structure comprises a metal oxide and/or a metal lithium salt.
  2. 2. The silicon-carbon material as set forth in claim 1 wherein the metal oxide comprises at least one of aluminum oxide and titanium oxide, and/or, The metal lithium salt includes at least one of lithium metaaluminate and lithium titanate.
  3. 3. The silicon-carbon material as claimed in claim 1 or 2, wherein the protruding structures have a lateral dimension of 1-1000nm, preferably 50-500nm, and/or, The raised structures have a vertical dimension of 10-300nm, and/or, The minimum distance between any two adjacent raised structures is greater than 10nm, preferably the minimum distance between any two adjacent raised structures is 300-1000nm.
  4. 4. A silicon-carbon material as claimed in any one of claims 1 to 3 wherein the mass percentage of the raised structures in the silicon-carbon material is 0.1 to 10%; preferably, in the silicon carbon material, the mass percentage of the protruding structure is 0.5-1%.
  5. 5. The silicon-carbon material as claimed in any one of claims 1 to 4, wherein the sphericity of the silicon-carbon material is not less than 0.85, preferably not less than 0.95, and/or, The silicon carbon material has a particle size concentration K <1.5, and/or, The specific surface area of the silicon carbon material is 1-500m 2 /g, preferably 100-200m 2 /g.
  6. 6. The silicon-carbon material of any one of claims 1-5 wherein the silicon-carbon matrix comprises a silicon-carbon core and a carbon coating layer on at least a portion of a surface of the silicon-carbon core, the raised structures being on at least a portion of the surface of the carbon coating layer.
  7. 7. The silicon-carbon material according to claim 6, wherein the D50 of the silicon-carbon material is 4-10 μm, preferably the D50 of the silicon-carbon material is 4-5 μm; and/or, the mass percentage of the carbon coating layer in the silicon-carbon material is 0.45-10%, preferably, the mass percentage of the carbon coating layer in the silicon-carbon material is 2-5%.
  8. 8. The silicon-carbon material of claim 6 or 7, wherein the silicon-carbon core comprises a porous carbon skeleton and amorphous silicon particles located in at least part of the surface and/or at least part of the pores of the porous carbon skeleton.
  9. 9. The silicon-carbon material according to claim 8, wherein the amorphous silicon particles are 9-60% by mass in the silicon-carbon material; Preferably, in the silicon carbon material, the amorphous silicon particles are 40-55% by mass.
  10. 10. A method for producing the silicon carbon material as set forth in any one of claims 1 to 9, comprising: carrying out surface treatment on the silicon carbon matrix to obtain an intermediate with at least part of the surface having C-H bonds; sequentially carrying out mixing treatment and heat treatment on the intermediate and a material source with a convex structure to obtain the silicon-carbon material; Wherein the material source of the protruding structure comprises a metal oxide and/or a lithium source.
  11. 11. The method of manufacturing according to claim 10, wherein the surface treatment comprises a plasma vapor deposition treatment; preferably, in the plasma vapor deposition process, the flow rate of the deposition gas is 10-1000mL/min, the deposition gas comprises hydrocarbon gas and hydrogen, and the volume ratio of the hydrocarbon gas to the hydrogen is (0.5-5): 1, and/or, In the plasma vapor deposition treatment, the pressure is 5-50Pa, the temperature is 300-600 ℃, the time is 10-60min, and the power is 600-800W.
  12. 12. The process according to claim 10 or 11, wherein the mixing is carried out at a rotational speed of 1000 to 5000rmp, a temperature of 30 to 100℃and a time of 5 to 60min, and/or, In the heat treatment, the temperature is 400-600 ℃ and the time is 4-20h.
  13. 13. A negative electrode sheet, characterized in that the negative electrode sheet comprises a negative electrode current collector and a negative electrode active layer positioned on at least one surface of the negative electrode current collector; The negative electrode active layer comprising the silicon-carbon material of any one of claims 1 to 9.
  14. 14. The negative electrode sheet of claim 13, wherein the negative electrode active layer further comprises a solid state electrolyte.
  15. 15. A battery comprising the silicon-carbon material of any one of claims 1-9; Or, a silicon-carbon material prepared by the preparation method of any one of claims 10 to 13; or, comprises the negative electrode sheet according to claim 13 or 14.
  16. 16. The battery of claim 15, wherein the battery is a solid state battery.
  17. 17. A battery comprising at least two cells according to claim 15 or 16.
  18. 18. An electronic device comprising the battery of claim 15 or 16 or comprising the battery pack of claim 17.

Description

Silicon-carbon material, negative plate, battery pack and electronic equipment Technical Field The invention relates to the technical field of electrochemistry, in particular to a silicon-carbon material, a negative plate, a battery pack and electronic equipment. Background With the continuous increase of global energy demands and the increasing environmental protection requirements, electric vehicles are receiving a great deal of attention due to the advantages of zero emission, and people put forward higher demands on the lithium ion batteries of the energy storage units of the electric vehicles. At present, the commercial lithium ion battery cathode material is mainly graphite, but the mass specific energy of the graphite is only 372mAh/g, and the requirements of people can not be met. Silicon is the material with the highest specific energy in all the anode materials found at present, the mass specific energy can reach 4200mAh/g, the volume specific energy can reach 9786mAh/cm 3, and the specific energy is more than 10 times of the current commercial graphite anode materials. However, when the existing silicon material is used for removing lithium from a battery, the volume expansion of the existing silicon material is up to 300%, so that SEI films are continuously grown, broken and thickened, the capacity of the battery is attenuated, and the cycle life of the battery is influenced. Disclosure of Invention In view of the above, the present invention provides a silicon carbon material that can improve the cycle performance of a battery when applied to the battery. The invention provides a preparation method of a silicon-carbon material, which can prepare the silicon-carbon material, is simple to operate and is suitable for wide popularization and application. The invention provides a negative plate which comprises the silicon-carbon material, and can improve the cycle performance of a battery when the negative plate is applied to the battery. The invention provides a battery which comprises any one of the silicon-carbon material, the silicon-carbon material prepared by the preparation method of the silicon-carbon material and the negative plate, and has excellent cycle performance. The invention provides a battery pack, which comprises the battery and has excellent cycle performance. The invention provides electronic equipment, which comprises the battery or the battery pack and has excellent endurance and service life. The first aspect of the invention provides a silicon-carbon material, which comprises a silicon-carbon matrix and a convex structure protruding out of the surface of the silicon-carbon matrix; The bump structure comprises a metal oxide and/or a metal lithium salt. The silicon carbon material as described above, wherein the metal oxide comprises at least one of aluminum oxide and titanium oxide, and/or, The metal lithium salt includes at least one of lithium metaaluminate and lithium titanate. The silicon carbon material as described above, wherein the lateral dimension of the raised structures is 1-1000nm, preferably the lateral dimension of the raised structures is 50-500nm, and/or, The raised structures have a vertical dimension of 10-300nm, and/or, The minimum distance between any two adjacent raised structures is greater than 10nm, preferably the minimum distance between any two adjacent raised structures is 300-1000nm. The silicon-carbon material, wherein in the silicon-carbon material, the mass percentage of the protruding structures is 0.1-10%; preferably, in the silicon carbon material, the mass percentage of the protruding structure is 0.5-1%. The silicon-carbon material as described above, wherein the sphericity of the silicon-carbon material is not less than 0.85, preferably not less than 0.95, and/or, The silicon carbon material has a particle size concentration K <1.5, and/or, The specific surface area of the silicon carbon material is 1-500m 2/g, preferably 100-200m 2/g. A silicon carbon material as described above wherein the silicon carbon matrix comprises a silicon carbon core and a carbon coating layer on at least a portion of a surface of the silicon carbon core, the raised structures being on at least a portion of the surface of the carbon coating layer. A silicon carbon material as described above wherein the D50 of the silicon carbon material is 4-10 μm, preferably the D50 of the silicon carbon material is 4-5 μm; and/or, the mass percentage of the carbon coating layer in the silicon-carbon material is 0.45-10%, preferably, the mass percentage of the carbon coating layer in the silicon-carbon material is 2-5%. A silicon carbon material as described above wherein the silicon carbon core comprises a porous carbon skeleton and amorphous silicon particles located at least partially on the surface and/or at least partially in the pores of the porous carbon skeleton. The silicon-carbon material, wherein in the silicon-carbon material, the amorphous silicon particles are 9