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CN-122025590-A - Photovoltaic waste silicon material and carbon nano tube three-dimensional network interpenetration quick-charging type silicon-carbon composite anode material and preparation method thereof

CN122025590ACN 122025590 ACN122025590 ACN 122025590ACN-122025590-A

Abstract

The invention discloses a photovoltaic waste silicon material and carbon nano tube three-dimensional network inserted quick-charging silicon-carbon composite anode material and a preparation method thereof, and belongs to the technical field of lithium ion battery anode materials. In the composite material designed by the invention, the photovoltaic waste silicon material is used as a silicon source, a three-dimensional conductive network is formed by dispersing carbon nanotubes and silicon, then graphite and the carbon source are introduced, so that the carbon nanotubes are inserted between the silicon and the graphite, and finally the silicon-carbon composite material with the carbon nanotube three-dimensional network insertion structure is prepared through spray drying and cracking carbonization. The three-dimensional conductive network constructed by the invention improves the electronic conductivity of the material, and is beneficial to the rapid intercalation and deintercalation of lithium ions, thereby endowing the composite material with excellent multiplying power performance and rapid charging capability. Meanwhile, the amorphous carbon coating generated by in-situ pyrolysis can cooperatively buffer the volume expansion of silicon in the circulation process, so that the conductivity, the structural stability and the circulation life of the composite material are obviously improved.

Inventors

  • HU ZHE
  • LI MENGLIN
  • WANG CHENCHEN

Assignees

  • 深圳大学

Dates

Publication Date
20260512
Application Date
20260211

Claims (9)

  1. 1. The rapid charging type silicon-carbon composite negative electrode material is characterized by comprising silicon, graphite, carbon nanotubes and amorphous carbon, wherein the silicon is derived from the photovoltaic waste silicon material, the carbon nanotubes form a three-dimensional network and are inserted between the silicon and the graphite, and the silicon, the graphite and the carbon nanotubes are coated in the amorphous carbon.
  2. 2. A method for preparing the photovoltaic waste silicon material and carbon nano tube three-dimensional network interpenetration quick-charging silicon-carbon composite anode material as claimed in claim 1, which is characterized by comprising the following steps: mixing the micron silicon powder with carbon nano tubes in dispersion liquid to obtain silicon/carbon nano tube slurry; adding graphite into the silicon/carbon nano tube slurry to form silicon-carbon nano tube-graphite mixed slurry; Dissolving a carbon source in a solvent to obtain a carbon source solution, mixing the carbon source solution with the silicon-carbon nano tube-graphite mixed slurry, and drying to obtain precursor powder; Mixing the precursor powder with water to obtain slurry, adding a binder to obtain a suspension, and then performing spray drying to obtain precursor particles; and (3) cracking and carbonizing the precursor particles in an inert atmosphere to obtain the quick-charging silicon-carbon composite anode material.
  3. 3. The preparation method according to claim 2, wherein the mass ratio of the micron silicon powder, the graphite, the carbon nano tube and the carbon source is 20% -50%, 40% -70%, 0.1% -2%, and 5% -20%.
  4. 4. The preparation method according to claim 2, wherein d50=1-3 μm of the micron silicon powder, and d50=10-20 μm of the graphite is artificial graphite or natural graphite.
  5. 5. The method according to claim 2, wherein the carbon source is at least one of glucose, sucrose, pitch, polyacrylonitrile, polyvinylpyrrolidone, polyimide, and polydopamine.
  6. 6. The preparation method of claim 2, wherein the solid content of the slurry is 5-40 wt%, the binder is sodium carboxymethyl cellulose, and the viscosity of the suspension is 100-500 cP.
  7. 7. The method according to claim 2, wherein the spray-drying inlet temperature is 150-300 ℃ and the spray-drying outlet temperature is 80-120 ℃.
  8. 8. The method according to claim 2, wherein the pyrolysis carbonization comprises the step of heating to 600-1000 ℃ at 5 ℃ per minute and preserving heat for 2-6 hours.
  9. 9. An application of the photovoltaic waste silicon material and carbon nano tube three-dimensional network interpenetrated fast-charging silicon-carbon composite anode material in the field of anode materials of lithium ion batteries.

Description

Photovoltaic waste silicon material and carbon nano tube three-dimensional network interpenetration quick-charging type silicon-carbon composite anode material and preparation method thereof Technical Field The invention relates to the technical field of lithium ion battery negative electrode materials, in particular to a photovoltaic waste silicon material and carbon nano tube three-dimensional network inserted quick-charging silicon-carbon composite negative electrode material and a preparation method thereof. Background With the rapid development of electric automobiles and portable electronic devices, the demands for energy density and rapid charging performance of lithium ion batteries are increasingly increasing. Silicon-based anode materials are widely focused on the high theoretical specific capacity (about 4200 mAh/g), however, the silicon has serious volume expansion (about 300%) in the charge and discharge process, which is easy to cause the problems of pulverization, poor cycle stability and the like, and meanwhile, the intrinsic conductivity of the silicon is poor, which restricts the high-rate performance of the battery. To alleviate the above problems, a strategy of compounding silicon with carbon materials (such as graphite, amorphous carbon, carbon nanotubes, etc.) is generally studied to improve electrode performance by means of buffer volume effect and conductivity enhancement of the carbon materials. However, simple physical mixing makes it difficult to construct efficient and stable conductive networks and buffer structures on a microscopic scale, and the deficiencies of ion and electron transport kinetics remain significant, especially under fast charge conditions. On the other hand, the photovoltaic industry produces a large amount of waste silicon materials each year, which have high purity, but have problems of uneven particle size distribution, strong surface activity, and the like, and have a problem of poor structural stability when used as a battery anode material directly. At present, the high-value utilization way of the photovoltaic waste silicon material is still limited, and development of a technical scheme capable of improving the electrochemical performance and realizing the recycling of resources is needed. At present, the preparation methods of the silicon-carbon composite materials are various, such as ball milling, spray drying, chemical vapor deposition and the like. However, in the prior art, it is difficult to construct continuous and stable conductive and buffer structures on a microscopic scale, which results in imperfect conductive networks and limited improvement of rate performance. Therefore, the rapid-charging type silicon-carbon composite anode material based on the photovoltaic waste silicon material and simultaneously provided with the three-dimensional conductive network and the multiple buffer structure and the large-scale preparation method thereof are developed, and the rapid-charging type silicon-carbon composite anode material has important scientific significance and application value. Disclosure of Invention The invention aims to provide a rapid-charging type silicon-carbon composite anode material with a three-dimensional network of photovoltaic waste silicon material and carbon nanotubes interposed and a preparation method thereof, so as to solve the problems in the background art. The three-dimensional conductive network constructed by the invention improves the electronic conductivity of the material, and is beneficial to the rapid intercalation and deintercalation of lithium ions, thereby endowing the composite material with excellent multiplying power performance and rapid charging capability. Meanwhile, the amorphous carbon coating generated by in-situ pyrolysis can cooperatively buffer the volume expansion of silicon in the circulation process, so that the conductivity, the structural stability and the circulation life of the composite material are obviously improved. In order to achieve the above purpose, the present invention provides the following technical solutions: According to one of the technical schemes, the rapid-charging type silicon-carbon composite anode material with the three-dimensional network interpenetration of the photovoltaic waste silicon material and the carbon nano tube comprises silicon, graphite, the carbon nano tube and amorphous carbon, wherein the silicon is derived from the photovoltaic waste silicon material, the carbon nano tube is interpenetrated between the silicon and the graphite to form the three-dimensional network, and the silicon, the graphite and the carbon nano tube are coated in the amorphous carbon. The second technical scheme of the invention is to provide a preparation method of the photovoltaic waste silicon material and carbon nano tube three-dimensional network interposed quick-charging silicon-carbon composite anode material, which comprises the following steps: mixing the micron silicon p