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CN-122025567-A - Porous carbon-silicon composite material and preparation method and application thereof

CN122025567ACN 122025567 ACN122025567 ACN 122025567ACN-122025567-A

Abstract

The invention discloses a porous carbon-silicon composite material, a preparation method and application thereof, and belongs to the technical field of battery materials. The preparation method of the porous carbon-silicon composite material comprises the steps of ball-milling and mixing porous carbon, silicon powder and a cross-linking agent according to the mass ratio of (20-60) (25-55) (0.5-30), and then performing pyrolysis. According to the method, a cross-linking agent is used in the ball milling process, forms a covalent bond between porous carbon and silicon powder through a chemical reaction, is combined with a pyrolysis process, is beneficial to enhancing the interfacial binding force between materials, further effectively inhibits the damage of the volume expansion of silicon to the electrode structure, and improves the cycle stability of the composite material. The preparation process is simple to operate, the conditions are easy to control, the preparation process is suitable for large-scale industrial production, the equipment cost is reduced, and the production efficiency is improved.

Inventors

  • Mu Xiaoya
  • HUANG SIMING
  • LI JI
  • YANG MIN
  • ZHANG LINGXIANG
  • KE XIN
  • LIU ZHAO
  • Cai Pengfu

Assignees

  • 四川华宜清创新材料科技有限公司

Dates

Publication Date
20260512
Application Date
20250827

Claims (10)

  1. 1. A preparation method of a porous carbon-silicon composite material is characterized by comprising the steps of ball-milling and mixing porous carbon, silicon powder and a cross-linking agent according to the mass ratio of (20-60) (25-55) (0.5-30), and then performing pyrolysis.
  2. 2. The method of claim 1, wherein the porous carbon has at least one of the following characteristics: the specific surface area of the porous carbon is 260m 2 /g～2200m 2 /g; and 2, the pore diameter of the porous carbon is 2 nm-3 nm.
  3. 3. The method according to claim 1 or 2, wherein the porous carbon is produced by carbonizing distillers grains; Preferably, the stillage is spent stillage; preferably, carbonization is performed in an inert atmosphere; preferably, the carbonization temperature is 300-1800 ℃ and the carbonization time is 1-24 hours.
  4. 4. The method according to claim 3, wherein the method further comprises pretreating the distillers grains before carbonizing, wherein the pretreatment comprises crushing the distillers grains, soaking in an acid solution, washing to neutrality, and drying; preferably, crushing to a particle size of 1-100 μm; preferably, the acid solution is an HCl solution with the concentration of 0.1 mol/L-20 mol/L; Preferably, the soaking time is 6-48 h.
  5. 5. The method of manufacturing as claimed in claim 1, wherein the silicon powder has a particle diameter of 0.015 μm to 500 μm.
  6. 6. The method according to claim 1, wherein the crosslinking agent comprises at least one of polyacrylic acid, polyvinyl alcohol, polyethylene glycol, polyimide, polyaniline, polypyrrole, polyvinylpyrrolidone, phenolic resin, chitosan, gelatin, and sodium alginate.
  7. 7. The method of claim 1, wherein ball milling comprises at least one of the following features: The characteristic 3 is that the ball milling medium used for ball milling comprises zirconia balls or agate balls; the ball milling medium used for ball milling has a diameter of 2 mm-20 mm; The ball-milling method is characterized in that the ball-material ratio used by ball milling is 1:1 to 30:1; the characteristic 6 is that the ball milling rotating speed is 200 r/min-1000 r/min; and 7, ball milling time is 0.5-36 h.
  8. 8. The preparation method according to claim 1, wherein the pyrolysis comprises the steps of preserving heat for 0.5-8 hours at 160-500 ℃ and then preserving heat for 0.5-24 hours at 300-1500 ℃ in an inert gas atmosphere; preferably, the heating rate in the pyrolysis process is 1-20 ℃ per minute; preferably, the inert gas includes at least one of argon, nitrogen, hydrogen and helium.
  9. 9. A porous carbon-silicon composite material characterized by being prepared by the preparation method of any one of claims 1 to 8.
  10. 10. A battery, characterized in that the negative electrode material of the battery comprises the porous carbon-silicon composite of claim 9.

Description

Porous carbon-silicon composite material and preparation method and application thereof Technical Field The invention relates to the technical field of battery materials, in particular to a porous carbon-silicon composite material and a preparation method and application thereof. Background With the rapid development of electric vehicles and portable electronic devices, lithium ion batteries with high energy density and long cycle life are increasingly demanded. Silicon becomes a cathode material with great potential due to its ultrahigh theoretical specific capacity (about 4200 mAh/g), but during charge and discharge, silicon undergoes a volume expansion of up to about 300%, which can lead to destruction of the electrode structure, falling of active materials, and serious influence on the cycle stability and service life of the battery. In this regard, compounding silicon with carbon materials is one of the effective strategies for mitigating silicon volume expansion. The silicon-carbon composite material prepared by the traditional method has a plurality of problems, such as weaker interfacial binding force between porous carbon and silicon, and the porous carbon and the silicon are easy to separate in the charge-discharge cycle of the battery, so that the utilization rate of active substances is reduced. In view of this, the present invention has been made. Disclosure of Invention The invention aims to provide a porous carbon-silicon composite material, and a preparation method and application thereof, so as to solve or improve the technical problems. The invention can be realized as follows: In the first aspect, the invention provides a preparation method of a porous carbon-silicon composite material, which comprises the following steps of ball-milling and mixing porous carbon, silicon powder and a cross-linking agent according to the mass ratio of (20-60): (25-55): (0.5-30), and then carrying out pyrolysis. In an alternative embodiment, the porous carbon has at least one of the following features: The specific surface area of the porous carbon is 260m 2/g～2200m2/g; And 2, the pore diameter of the porous carbon is 2 nm-3 nm. In an alternative embodiment, the porous carbon is prepared by carbonizing distillers grains. In an alternative embodiment, the stillage is spent stillage. In an alternative embodiment, carbonization is performed in an inert atmosphere. In an alternative embodiment, the carbonization temperature is 300 ℃ to 1800 ℃ and the carbonization time is 1h to 24h. In an alternative embodiment, the method further comprises pretreatment of the distillers grains before carbonization, wherein the pretreatment comprises the steps of crushing the distillers grains, soaking the distillers grains in an acid solution, and then washing the distillers grains to be neutral and drying the distillers grains. In an alternative embodiment, the particles are crushed to a particle size of 1 μm to 100 μm. In an alternative embodiment, the acid solution is HCl solution with a concentration of 0.1mol/L to 20 mol/L. In an alternative embodiment, the soaking time is 6-48 hours. In an alternative embodiment, the silicon powder has a particle size of 0.015 μm to 500 μm. In an alternative embodiment, the cross-linking agent comprises at least one of polyacrylic acid, polyvinyl alcohol, polyethylene glycol, polyimide, polyaniline, polypyrrole, polyvinylpyrrolidone, phenolic resin, chitosan, gelatin, and sodium alginate. In alternative embodiments, ball milling includes at least one of the following features: The characteristic 3 is that the ball milling medium used for ball milling comprises zirconia balls or agate balls; the ball milling medium used for ball milling has a diameter of 2 mm-20 mm; The ball-milling method is characterized in that the ball-material ratio used by ball milling is 1:1 to 30:1; the characteristic 6 is that the ball milling rotating speed is 200 r/min-1000 r/min; and 7, ball milling time is 0.5-36 h. In an alternative embodiment, the pyrolysis comprises the steps of preserving heat for 0.5-8 hours at 160-500 ℃ and then preserving heat for 0.5-24 hours at 300-1500 ℃ in an inert gas atmosphere. In an alternative embodiment, the rate of temperature rise during pyrolysis is 1 ℃ per minute to 20 ℃ per minute. In alternative embodiments, the inert gas includes at least one of argon, nitrogen, hydrogen, and helium. In a second aspect, the present invention provides a porous carbon-silicon composite material prepared by the method of any one of the preceding embodiments. In a third aspect, the present invention provides a battery, the negative electrode material of which comprises the porous carbon-silicon composite of the foregoing embodiment. The beneficial effects of the invention include: According to the invention, the porous carbon prepared from the vinasse, the silicon powder and the cross-linking agent are ball-milled and mixed according to a specific proportion, and then the mixture is pyroly