Search

CN-121983527-A - Negative electrode active material, preparation method thereof, negative electrode plate, battery pack and electric equipment

CN121983527ACN 121983527 ACN121983527 ACN 121983527ACN-121983527-A

Abstract

The invention provides a negative electrode active material and a preparation method thereof, a negative electrode plate, a battery pack and electric equipment. The negative electrode active material comprises a silicon-based substrate, wherein the surface of the silicon-based substrate is provided with first pores, the pore diameter range of the first pores is 1 nm-120 nm, and the Dv50 of the negative electrode active material is 80 nm-900 nm. The cathode active material has higher conductivity and stability, and is beneficial to improving the multiplying power performance and the cycle capacity retention rate of the battery.

Inventors

  • YAN ZHILIN
  • LIU ZHAOBO
  • XU CHAQING

Assignees

  • 比亚迪股份有限公司

Dates

Publication Date
20260505
Application Date
20251024

Claims (15)

  1. 1. A negative electrode active material characterized by comprising a silicon-based matrix; The surface of the silicon-based substrate is provided with a first pore; the aperture range of the first pore is 1 nm-120 nm; And the Dv50 of the negative electrode active material is 80-900 nm.
  2. 2. The anode active material according to claim 1, wherein Dv50 of the anode active material is preferably 80nm to 150nm; And/or, the pore diameter range of the first pore is preferably 10 nm-30 nm; and/or, the silicon-based substrate comprises polysilicon; And/or the silicon-based matrix comprises M element, wherein the M element comprises one or more of nitrogen element, phosphorus element and boron element, and the atomic ratio of the M element in the silicon-based matrix is 0.1-10%.
  3. 3. The anode active material according to claim 1 or 2, further comprising a carbon layer coated on at least part of the surface of the silicon-based substrate.
  4. 4. The negative electrode active material according to claim 3, wherein the carbon layer includes an M element, the mass ratio of the M element in the carbon layer is 5wt% to 30wt%, and the M element includes one or more of a nitrogen element, a phosphorus element, and a boron element.
  5. 5. The anode active material according to any one of claims 1 to 4, wherein the silicon-based substrate has second pores inside; The pore diameter of the second pore ranges from 1nm to 120nm, preferably from 10nm to 30nm.
  6. 6. The negative electrode active material according to claim 3 or 4, wherein the ratio of the size of the silicon-based substrate to the thickness of the carbon layer is (80 to 300): 1, preferably the thickness of the carbon layer is 1 to 5nm.
  7. 7. The anode active material according to any one of claims 1 to 6, wherein the anode active material is produced using a method comprising: carrying out first vapor deposition treatment on raw material gas comprising a silicon source to obtain a silicon-based substrate; Etching the silicon-based substrate to obtain a negative electrode active material with a Dv50 of 80-900 nm; and the pH value of the etching treatment is 8-12.
  8. 8. A method for producing the anode active material according to any one of claims 1 to 7, comprising the steps of: carrying out first vapor deposition treatment on raw material gas comprising a silicon source to obtain a silicon-based substrate; Etching the silicon-based substrate to obtain a negative electrode active material with a Dv50 of 80-900 nm; and the pH value of the etching treatment is 8-12.
  9. 9. The method for producing a negative electrode active material according to claim 8, wherein, The raw material gas for the first gas phase treatment also comprises an M source, the deposition temperature of the first gas phase deposition treatment is 700-1000 ℃, the deposition time is 2-10 hours, and the volume ratio of the M source to the silicon source is 1:4-1:24; And/or, the first vapor deposition treatment further comprises the step of carrying out second vapor deposition treatment on raw material gas comprising a carbon source, an M source and raw materials of the silicon-based matrix to obtain a negative electrode active material, wherein at least part of the surface of the silicon-based matrix is coated with a carbon layer; The deposition temperature of the second vapor deposition treatment is 700-1000 ℃ and the deposition time is 0.5-2 h, and the volume ratio of the M source to the carbon source in the second vapor deposition treatment is 1 (2-9).
  10. 10. The method according to claim 8 or 9, wherein the etching treatment includes stirring a product after the second vapor deposition treatment with an alkali solution to obtain the anode active material; Wherein the treatment temperature of the stirring treatment is 40-80 ℃ and the treatment time is 0.5-10 h; The alkali comprises one or more of potassium hydroxide, sodium hydroxide, ethylenediamine, hydrazine, ammonia water and urea.
  11. 11. The method for producing a negative electrode active material according to claim 9, wherein the silicon source comprises one or more of monosilane, disilane, dichlorosilane, trichlorosilane, tetrachlorosilane, hexachlorodisilane; and/or the nitrogen source comprises one or more of ammonia gas, nitrous oxide, nitric oxide, nitrogen dioxide, nitrous oxide; And/or the phosphorus source comprises one or more of phosphane, phosphane methane and phosphorus oxychloride; And/or the boron source comprises one or more of diborane, ding Pengwan, pentaborane.
  12. 12. A negative electrode sheet comprising the negative electrode active material according to any one of claims 1 to 7, or the negative electrode active material produced by the method for producing a negative electrode active material according to any one of claims 8 to 11.
  13. 13. A battery comprising the negative electrode sheet of claim 12.
  14. 14. A battery comprising at least two cells according to claim 13.
  15. 15. A powered device comprising the battery of claim 13, or the battery pack of claim 14.

Description

Negative electrode active 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 active material, a preparation method thereof, a negative electrode plate, a battery pack and electric equipment. Background Silicon-based anode active materials are considered as ideal anode materials for secondary batteries because of their high specific capacity (about 4200 mAh/g). However, the conductivity of the silicon-based anode active material is obviously lower than that of the traditional carbon-based anode active material such as graphite, so that the electrochemical reaction kinetics process of the silicon-based anode active material under the high-rate condition is limited, and the rate performance of the secondary battery is further limited. In addition, the silicon-based anode active material may cause serious volume expansion problems during battery cycling, resulting in a decrease in the cycling capacity retention rate of the battery. Therefore, there is a need to improve a silicon-based anode active material with better conductivity and higher stability to improve the rate capability and the cycle capacity retention of the battery. Disclosure of Invention The invention provides a negative electrode active material, a preparation method thereof, a negative electrode plate, a battery pack and electric equipment, wherein the negative electrode active material has higher conductivity and stability, and is beneficial to improving the multiplying power performance and the cycle capacity retention rate of the battery. The embodiment of the invention provides a cathode active material, The surface of the silicon-based substrate is provided with a first pore; the aperture range of the first pore is 1 nm-120 nm; And the Dv50 of the negative electrode active material is 80-900 nm. According to some embodiments of the invention, the Dv50 of the negative electrode active material is preferably 80-150 nm; And/or, the pore diameter range of the first pore is preferably 10 nm-30 nm; and/or, the silicon-based substrate comprises polysilicon; And/or the silicon-based matrix comprises M element, wherein the M element comprises one or more of nitrogen element, phosphorus element and boron element, and the atomic ratio of the M element in the silicon-based matrix is 0.1-10%. According to some embodiments of the invention, the negative electrode active material further comprises a carbon layer coated on at least part of the surface of the silicon-based substrate. According to some embodiments of the invention, the carbon layer comprises M element, the mass ratio of the M element in the carbon layer is 5-30wt%, and the M element comprises one or more of nitrogen element, phosphorus element and boron element. Some embodiments of the invention, the silicon-based substrate has a second aperture therein; The pore diameter of the second pore ranges from 1nm to 120nm, preferably from 10nm to 30nm. In some embodiments of the invention, the ratio of the size of the silicon-based substrate to the thickness of the carbon layer is (80-300): 1, preferably the thickness of the carbon layer is 1-5 nm. In some embodiments of the present invention, the negative electrode active material is prepared using a method comprising: carrying out first vapor deposition treatment on raw material gas comprising a silicon source to obtain a silicon-based substrate; Etching the silicon-based substrate to obtain a negative electrode active material with a Dv50 of 80-900 nm; and the pH value of the etching treatment is 8-12. The embodiment of the invention also provides a preparation method of the anode active material, which comprises the following steps: carrying out first vapor deposition treatment on raw material gas comprising a silicon source to obtain a silicon-based substrate; Etching the silicon-based substrate to obtain a negative electrode active material with a Dv50 of 80-900 nm; and the pH value of the etching treatment is 8-12. According to some embodiments of the invention, the feed gas for the first vapor phase treatment further comprises an M source, the deposition temperature of the first vapor phase deposition treatment is 700-1000 ℃, the deposition time is 2-10 h, and the volume ratio of the M source to the silicon source is 1:4-1:24; And/or, the first vapor deposition treatment further comprises the step of carrying out second vapor deposition treatment on raw material gas comprising a carbon source, an M source and raw materials of the silicon-based matrix to obtain a negative electrode active material, wherein at least part of the surface of the silicon-based matrix is coated with a carbon layer; The deposition temperature of the second vapor deposition treatment is 700-1000 ℃ and the deposition time is 0.5-2 h, and the volume ratio of the M source to the carbon source in the second v