Search

CN-122000337-A - Metal/heteroatom co-doped silicon-carbon anode material and preparation method and application thereof

CN122000337ACN 122000337 ACN122000337 ACN 122000337ACN-122000337-A

Abstract

The invention provides a metal/heteroatom co-doped silicon-carbon anode material, and a preparation method and application thereof, and belongs to the technical field of lithium ion battery materials. According to the invention, through the in-situ growth doping mode, the metal compound and the hetero atoms are uniformly distributed on the porous carbon substrate, so that not only is the electron conductivity of the material improved, but also the diffusion rate of lithium ions in the material and at the interface is improved, and the reaction kinetics of the silicon-carbon anode material is cooperatively improved. Meanwhile, the prepared silane deposited silicon carbon anode material has good conductivity, high structural stability and long cycle life.

Inventors

  • LI SHENG
  • Wang Daomiao
  • CAO ENDE
  • CHEN ZIHAO
  • LAI GUITANG
  • FANG BIN
  • HUANG SHIQIANG
  • CHEN JUNYI
  • MAO MIAOMIAO
  • WANG FANGRUI
  • YUAN LIANG

Assignees

  • 银硅(宁波)科技有限公司
  • 银硅(宜昌)科技有限公司

Dates

Publication Date
20260508
Application Date
20260311

Claims (10)

  1. 1. The preparation method of the metal/heteroatom co-doped silicon-carbon composite material is characterized by comprising the following steps of: Mixing a carbon source, an activating agent, metal salt, a nitrogen source and a phosphorus source with water, and complexing to obtain a precursor; carbonizing the precursor to obtain multiphase doped porous carbon; And under the condition of shielding gas, introducing silane gas into the multiphase doped porous carbon, performing vapor deposition, introducing carbon source gas, and performing carbon coating to obtain the metal/heteroatom co-doped silicon-carbon composite material.
  2. 2. The method of claim 1, wherein the carbon source comprises one of ethylenediamine tetraacetic acid and ethylenediamine tetraacetate salts.
  3. 3. The preparation method of the catalyst according to claim 1, wherein the activator comprises one of potassium hydroxide, sodium hydroxide and potassium carbonate, and the mass ratio of the activator to the carbon source is 1:1-3.
  4. 4. The preparation method of the metal salt according to claim 1, wherein the metal salt comprises one or more of nickel nitrate, ferric nitrate, cobalt nitrate, molybdate, tungstate and vanadate, and the mass ratio of the metal salt to the carbon source is 1:3-10.
  5. 5. The preparation method of the catalyst according to claim 1, wherein the nitrogen source comprises one or more of melamine, dicyandiamide and urea, the phosphorus source comprises phosphate, the mass ratio of the carbon source to the nitrogen source is 1:0.2-2, and the mass ratio of the carbon source to the phosphorus source is 1:0.2-1.
  6. 6. The preparation method of the carbon black powder according to claim 1, wherein the carbonization temperature is 700-1000 ℃ and the carbonization time is 2-10 hours, and the carbonization atmosphere is one or more of nitrogen, argon and helium.
  7. 7. The preparation method of claim 1, wherein the shielding gas comprises one or more of nitrogen, argon and helium, the silane gas comprises one or two of monosilane and disilane, the flow ratio of the silane gas to the shielding gas is 1:1-10, the vapor deposition temperature is 500-1000 ℃ and the time is 2-24 h.
  8. 8. The preparation method of the carbon-coated glass fiber reinforced plastic composite material according to claim 1 or 7, wherein the carbon source gas comprises one or more of methane, ethane, propane, acetylene and propyne, the flow ratio of the carbon source gas to the shielding gas is 1:1-10, the temperature of the carbon coating is 500-1000 ℃ and the time is 2-24 h.
  9. 9. The metal/heteroatom co-doped silicon-carbon composite material prepared by the preparation method according to any one of claims 1-8, wherein the Si content is 10-80 wt%, the carbon content is 10-80 wt%, and the metal compound content is 1-10 wt%.
  10. 10. The use of the metal/heteroatom co-doped silicon carbon composite material of claim 9 in a lithium ion battery anode material.

Description

Metal/heteroatom co-doped silicon-carbon anode material and preparation method and application thereof Technical Field The invention relates to the technical field of lithium ion battery materials, in particular to a metal/heteroatom co-doped silicon-carbon anode material, and a preparation method and application thereof. Background Lithium ion secondary batteries have become a core power source for portable electronic devices, electric vehicles and large-scale energy storage systems by virtue of their high energy density, long cycle life, low self-discharge rate and the like. However, currently, the commercial lithium ion battery mainly adopts graphite materials as the negative electrode, has lower theoretical specific capacity, and is difficult to meet the requirements of the next-generation high-energy-density battery. The Si material has theoretical specific capacity as high as 4200 mAh/g, but the huge volume expansion (about 300%) generated in the charge and discharge process seriously damages the structural stability and the cycle performance of the electrode, and greatly restricts the commercialization popularization and application of the electrode. In order to address the above-described drawbacks of Si-based cathodes, researchers have employed silicon-carbon (Si/C) composite strategies for modification. Particularly, the silicon-carbon anode material using porous carbon as a framework uniformly loads nano silicon into a pore structure by a chemical vapor deposition technology, and the volume expansion rate of the silicon can be remarkably reduced, so that the silicon-carbon anode material is widely studied. At present, the deposition type silicon-carbon anode material still has the problems of poor conductivity, slow reaction kinetics, poor interface stability and the like. The common method is to modify the porous carbon substrate, i.e. to dope non-metallic heteroatoms or to introduce metallic elements/metallic compounds, to improve the conductivity and interfacial stability of the composite material. However, the optimization of the material performance by a single doping strategy has obvious limitation, and the core problems of electron/ion transmission rate, interface stability and the like of the silicon-carbon negative electrode cannot be synchronously solved due to the lack of multiphase synergistic effect. In addition, the partial doping process is relatively complex, and hetero atoms or metal/metal compounds are unevenly distributed in the porous carbon, so that preferential nucleation and local agglomeration in the silicon deposition process are easily initiated, and the uniformity and stability of the material structure are further damaged. Therefore, a high-efficiency process method is still required to be explored to improve the dynamic defect of the silicon-carbon negative electrode, and synchronously improve the interface stability and the structural stability of the material, so that the excellent electrochemical performance of the novel silicon-carbon negative electrode material is realized. Disclosure of Invention The invention aims to provide a metal/heteroatom co-doped silicon-carbon anode material, a preparation method and application thereof, which can improve the dynamic defect of a silicon-carbon anode and improve the interface stability and the structural stability of the material. In order to achieve the above object, the present invention provides the following technical solutions: the invention provides a preparation method of a metal/heteroatom co-doped silicon-carbon composite material, which comprises the following steps: Mixing a carbon source, an activating agent, metal salt, a nitrogen source and a phosphorus source with water, and complexing to obtain a precursor; carbonizing the precursor to obtain multiphase doped porous carbon; And under the condition of shielding gas, introducing silane gas into the multiphase doped porous carbon, performing vapor deposition, introducing carbon source gas, and performing carbon coating to obtain the metal/heteroatom co-doped silicon-carbon composite material. Preferably, the carbon source comprises one of ethylenediamine tetraacetic acid and ethylenediamine tetraacetate. Preferably, the activating agent comprises one of potassium hydroxide, sodium hydroxide and potassium carbonate, and the mass ratio of the activating agent to the carbon source is 1:1-3. Preferably, the metal salt comprises one or more of nickel nitrate, ferric nitrate, cobalt nitrate, molybdate, tungstate and vanadate, and the mass ratio of the metal salt to the carbon source is 1:3-10. Preferably, the nitrogen source comprises one or more of melamine, dicyandiamide and urea, the phosphorus source comprises phosphate, the mass ratio of the carbon source to the nitrogen source is 1:0.2-2, and the mass ratio of the carbon source to the phosphorus source is 1:0.2-1. Preferably, the carbonization temperature is 700-1000 ℃ and the carbonization time is 2-10 hours