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CN-120878800-B - Preparation method of anti-aging lithium battery electrode material

CN120878800BCN 120878800 BCN120878800 BCN 120878800BCN-120878800-B

Abstract

The invention relates to a preparation method of an anti-aging lithium battery electrode material, and belongs to the technical field of electrode materials. The preparation method comprises the steps of firstly carrying out surface modification on silicon powder by adopting a silane coupling agent, mixing graphene oxide powder with N-methyl pyrrolidone, adding polyvinylpyrrolidone as a dispersing agent, carrying out ice bath ultrasonic treatment to obtain a dispersing liquid, carrying out high-energy ball milling compounding on the two dispersing liquids, drying by supercritical CO 2 to obtain a porous compound, then carrying out vapor deposition on the surface of the compound to form a nitrogen-doped carbon coating layer, finally carrying out mixed coating on the compound, conductive carbon black and PVDF, and carrying out rolling, vacuum drying and hot-pressing prelithiation treatment to obtain the anti-aging electrode material with high capacity and long cycle life.

Inventors

  • WEI ZENG

Assignees

  • 上海意定新材料科技有限公司

Dates

Publication Date
20260512
Application Date
20250716

Claims (6)

  1. 1. A preparation method of an anti-aging lithium battery electrode material is characterized by comprising the following specific steps of, S1, dispersing 5-10 parts by weight of silicon powder in 5-10 parts by weight of isopropanol solution, adding a silane coupling agent KH550, and performing ultrasonic treatment at 40-45 ℃ for 1-2 hours to obtain a dispersion liquid A; s2, adding 3-5 parts by weight of graphene oxide powder into 80-100 parts by weight of N-methylpyrrolidone so that the solid-liquid mass ratio is 2-3 mg/mL, adding 0.3-0.5 part by weight of dispersing agent, and performing ultrasonic treatment for 3-4 hours under ice bath to obtain a dispersing liquid B; S3, putting the dispersion liquid A and the dispersion liquid B into a ball milling tank, wherein the ball material ratio is (10-15): 1, adopting zirconia grinding balls with the diameter of 5mm, the ball milling speed is 200-300 rpm, the ball milling time is 12-16 h, washing 3 times by using ethanol, and drying by using supercritical CO 2 to obtain a compound C; S4, placing the compound in a tube furnace, raising the temperature to 800 ℃ in an argon atmosphere, preserving heat for 2-3 hours at 800 ℃, wherein the preserving heat atmosphere is a mixed gas of methane, ammonia and carrier gas, and then naturally cooling to room temperature to obtain a compound D; S5, mixing the compound D, conductive carbon black and PVDF, coating the mixture on a copper foil, wherein the loading amount is 1-2 mg/cm 2 , vacuum drying the mixture at 120 ℃ to 12 h, rolling the mixture to a compaction density of 1.6-1.8 g/cm 3 , and then placing the mixture in a customized hot press for pre-lithiation treatment to obtain the anti-aging lithium battery electrode material; The dispersing agent in the S2 is polyvinylpyrrolidone; The supercritical CO 2 in the step S3 is dried, the drying temperature is 40-48 ℃, and the pressure is 10-15 MPa; The volume ratio of the mixed gas of methane, ammonia and carrier gas in the S4 is (3-4) 1:10, wherein the carrier gas is argon containing 5% ferrocene by volume.
  2. 2. The preparation method of the anti-aging lithium battery electrode material according to claim 1, wherein the addition amount of the silane coupling agent KH550 in the S1 is 1-3% of the mass of silicon powder.
  3. 3. The method for preparing the anti-aging lithium battery electrode material according to claim 1, wherein the ball milling mode in the step S3 is to stop radiating for 15min every 1h of operation.
  4. 4. The preparation method of the anti-aging lithium battery electrode material according to claim 1, wherein the temperature rise rate in the step S4 is 5-10 ℃ per minute.
  5. 5. The preparation method of the anti-aging lithium battery electrode material according to claim 1, wherein in the step S5, the compound D, the conductive carbon black and the PVDF are mixed according to a mass ratio of (18-20): 1:1.
  6. 6. The method for preparing the anti-aging lithium battery electrode material according to claim 1, wherein the temperature of the lithium foil side in the pre-lithiation treatment in the step S5 is 60-65 ℃, the temperature of the pole piece side is 40-45 ℃, the pressure is 0.3-0.5 MPa, the time is 1h, and the thickness of the lithium foil is 50 μm.

Description

Preparation method of anti-aging lithium battery electrode material Technical Field The invention belongs to the technical field of electrode materials, and relates to a preparation method of an anti-aging lithium battery electrode material. Background The improvement of the energy density and the cycle life of the lithium ion battery serving as a core energy storage device is always a key requirement of the industry. The silicon-based anode material is regarded as an ideal candidate because of high theoretical specific capacity, but the practical application is limited by the problems that firstly, the volume expansion rate exceeds 300% in the charge and discharge process, so that an electrode is cracked and an active substance is separated, secondly, an excessive thick SEI film is generated by continuous side reaction of the silicon surface and electrolyte, active lithium is consumed, capacity attenuation is aggravated, thirdly, the electronic conductivity of the silicon is low, and the traditional conductive additives such as carbon black are difficult to construct a high-efficiency conductive network, and particularly, the performance attenuation is remarkable under high load. In the prior art, the nano silicon particles can relieve volume expansion, are easy to agglomerate and high in preparation cost, can be compounded with materials such as graphene and the like to improve conductivity, but have weak interface binding force, are easy to generate phase separation in long-term circulation, and the carbon coating or pre-lithiation technology can inhibit SEI film thickening or compensate lithium loss, but the uniformity of a carbon layer is difficult to control, and the traditional pre-lithiation method is easy to cause lithium dendrite and has potential safety hazard. Therefore, a method for preparing an anti-aging lithium battery electrode material is needed. Disclosure of Invention The invention aims to provide a preparation method of an anti-aging lithium battery electrode material, which has the characteristics of good anti-aging performance and electrochemical performance. The aim of the invention can be achieved by the following technical scheme: A preparation method of an anti-aging lithium battery electrode material comprises the following specific steps of, S1, dispersing 5-10 parts by weight of silicon powder in 5-10 parts by weight of isopropanol solution, adding a silane coupling agent KH550, and performing ultrasonic treatment at 40-45 ℃ for 1-2 hours to obtain a dispersion liquid A; s2, adding 3-5 parts by weight of graphene oxide powder into 80-100 parts by weight of N-methylpyrrolidone so that the solid-liquid mass ratio is 2-3 mg/mL, adding 0.3-0.5 part by weight of dispersing agent, and performing ultrasonic treatment for 3-4 hours under ice bath to obtain a dispersing liquid B; S3, putting the dispersion liquid A and the dispersion liquid B into a ball milling tank, wherein the ball material ratio is (10-15): 1, adopting zirconia grinding balls with the diameter of 5mm, the ball milling speed is 200-300 rpm, the ball milling time is 12-16 h, washing 3 times by using ethanol, and drying by using supercritical CO 2 to obtain a compound C; S4, placing the compound in a tube furnace, raising the temperature to 800 ℃ in an argon atmosphere, preserving heat for 2-3 hours at 800 ℃, wherein the preserving heat atmosphere is a mixed gas of methane, ammonia and carrier gas, and then naturally cooling to room temperature to obtain a compound D; And S5, mixing the compound D, the conductive carbon black and PVDF, coating the mixture on a copper foil, carrying out vacuum drying at 120 ℃ for 12 h with the loading capacity of 1-2 mg/cm 2, rolling the mixture until the compaction density is 1.6-1.8 g/cm 3, and then placing the mixture in a customized hot press for pre-lithiation treatment to obtain the anti-aging lithium battery electrode material. As a preferable technical scheme of the invention, the addition amount of the silane coupling agent KH550 in the S1 is 1-3% of the mass of the silicon powder. As a preferable technical scheme of the invention, the dispersing agent in the S2 is polyvinylpyrrolidone. As a preferable technical scheme of the invention, the ultrasonic frequency in the S2 is 10-20 kHz, and the power is 500-600W. As a preferable technical scheme of the invention, the ball milling mode in the step S3 is to stop radiating for 15min every 1h of working. As a preferable technical scheme of the invention, the supercritical CO 2 in the step S3 is dried at the drying temperature of 40-48 ℃ and the pressure of 10-15 MPa. As a preferable technical scheme of the invention, the temperature rising rate in the step S4 is 5-10 ℃ per minute. As a preferable technical scheme of the invention, the volume ratio of the mixed gas of methane, ammonia and carrier gas in the S4 is (3-4): 1:10, wherein the carrier gas is argon containing 5% ferrocene by volume. As a preferable technical scheme of the in