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CN-121641923-B - Metal fluoride coated silicon-carbon negative electrode material and preparation method thereof

CN121641923BCN 121641923 BCN121641923 BCN 121641923BCN-121641923-B

Abstract

The application discloses a silicon-carbon anode material coated with metal fluoride and a preparation method thereof, the preparation method comprises the steps of S100, carrying out vapor deposition on pore channels and the outer surface of porous carbon in inert gas by using a silane gas source and a carbon gas source to obtain a first product, S200, heating and stirring the first product, a metal source and an ammonia source in a solvent in a water bath, drying the obtained solid product, carrying out heat treatment in inert atmosphere to obtain a second product coated with metal oxide, wherein the solvent is one or more of ethanol, distilled water, methanol and acetone, and S300, mixing the second product with ammonium fluoride, and carrying out ball milling and then carrying out heat treatment to obtain the silicon-carbon anode material coated with metal fluoride. According to the application, firstly, through vapor deposition, silicon atoms and carbon atoms form firm chemical bonding with carbon atoms on the surface of porous carbon, and the metal fluoride is coated outside the first product, so that a stable solid electrolyte interface film is formed, and the cycle life is prolonged.

Inventors

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

Assignees

  • 银硅(宁波)科技有限公司

Dates

Publication Date
20260508
Application Date
20260203

Claims (9)

  1. 1. The preparation method of the silicon-carbon anode material coated with the metal fluoride is characterized by comprising the following steps of: s100, performing vapor deposition on pore channels and the outer surface of porous carbon in inert gas by using a silane gas source and a carbon gas source to obtain a first product; S200, heating and stirring the first product, a metal source and an ammonia source in a solvent through a water bath, drying the mixture, and performing heat treatment on the obtained solid product in an inert atmosphere to obtain a second product coated with a metal oxide, wherein the solvent is one or more of ethanol, distilled water, methanol and acetone, the metal source is metal chloride or metal nitrate, and the ammonia source is urea; And S300, mixing the second product with ammonium fluoride, performing ball milling, and performing heat treatment to obtain the silicon-carbon anode material coated with the metal fluoride.
  2. 2. The method of claim 1, wherein the metal source is one or more of aluminum chloride, magnesium chloride, barium chloride, calcium chloride, aluminum nitrate, magnesium nitrate, barium nitrate, and calcium nitrate.
  3. 3. The method according to claim 1, wherein the mass of the first product in the step S200 is n 1 and the mass of the metal source is n 2 ,0.01n 1 ≤n 2 ≤0.1n 1 .
  4. 4. The preparation method according to claim 1, wherein the water bath treatment temperature in the step S200 is 60 ℃ to 90 ℃, the drying treatment temperature is 60 ℃ to 120 ℃, the drying treatment time is 5h to 15h, the heat treatment temperature is 350 ℃ to 550 ℃, and the heat treatment time is 3h to 12h.
  5. 5. The method according to claim 1, wherein the ball-milling process in the step S300 has a ball-to-material ratio of (5-20) of 1, a ball-milling rotation speed of 500-2500 rpm, a ball-milling time of 5-20 hours, a heat-treatment temperature of 350-550 ℃, a heat-treatment time of 5-12 hours, and a metal fluoride coating amount of 0.5-5 wt.%.
  6. 6. The preparation method of claim 1, wherein the porosity of the porous carbon is more than or equal to 50%, the pore size of the porous carbon is 10-200 nm, and the mass fraction of silicon element in the silicon-carbon anode material is 10-90 wt%.
  7. 7. The preparation method according to claim 1, wherein at least one of the following conditions is satisfied: the silane gas source is one or more of monosilane and disilane; The carbon source is one or more of methane, ethane, propane, acetylene and propyne; The inert gas is one or more of nitrogen, argon and helium.
  8. 8. The method according to claim 1, wherein in the step S100, the volume flow ratio of the carbon source to the inert gas is 1 (1-10), the vapor deposition time is 1-12 h, and the deposition temperature is 400-1000 ℃.
  9. 9. The silicon-carbon anode material is characterized by being prepared by the preparation method of any one of claims 1-8.

Description

Metal fluoride coated silicon-carbon negative electrode material and preparation method thereof Technical Field The application relates to the technical field of negative electrode materials, in particular to a silicon-carbon negative electrode material coated with metal fluoride and a preparation method thereof. Background At present, lithium ion batteries are widely used as high-efficiency energy storage devices in the fields of electric automobiles, portable electronic equipment, renewable energy storage and the like. In order to further increase the application range of the lithium ion battery, the continuous increase of the energy density is the core direction of research and development in the industry. The negative electrode material is used as a key component in the lithium ion battery, and directly influences the energy storage capacity, the charging speed, the service life and the safety of the lithium ion battery, so that the performance breakthrough of the negative electrode material is a great key constraint factor. The theoretical specific capacity of a traditional graphite negative electrode is close to the physical limit (about 372 mAh/g) of the traditional graphite negative electrode, and future demands are difficult to meet. In contrast, silicon-based anodes are considered to be ideal choices for next-generation anode materials by virtue of their ultra-high theoretical specific capacity (4200 mAh/g), suitable low lithium intercalation potential (< 0.5V vs. Li/Li +), and rich elemental reserves. However, the large-scale commercialization of silicon-based cathodes has two major challenges, namely, severe volume effect, high volume expansion and shrinkage of up to 300% in the process of charging and discharging, namely, in the process of lithium intercalation and deintercalation, which easily causes active particles to be broken, electrode structures to be pulverized and conductive networks to be destroyed, and severe interfacial instability, continuous volume change causes repeated breaking and regeneration of a solid electrolyte interfacial film on the surface of particles, continuously consumes electrolyte and active lithium, and increases interfacial impedance, thereby causing serious capacity attenuation and cycle life reduction phenomena. Therefore, in order to increase the quality and stability of the negative electrode material, it is necessary to optimize a preparation process for preparing the negative electrode material with high stability and service life. Disclosure of Invention The application aims to provide a metal fluoride coated silicon-carbon anode material and a preparation method thereof, which are beneficial to improving the service stability and service life of the silicon-carbon anode material and further improving the intrinsic conductivity of the silicon-carbon anode material. The preparation method of the silicon-carbon anode material coated with the metal fluoride comprises the following steps of S100, performing vapor deposition on pore channels and the outer surface of porous carbon in inert gas by using a silane gas source and a carbon gas source to obtain a first product, S200, heating and stirring the first product, the metal source and an ammonia source in a solvent in a water bath, drying the obtained solid product, and performing heat treatment in the inert atmosphere to obtain a second product coated with the metal oxide, wherein the solvent is one or more of ethanol, distilled water, methanol and acetone, and S300, mixing the second product with ammonium fluoride, performing ball milling, and performing heat treatment to obtain the silicon-carbon anode material coated with the metal fluoride. In some embodiments, the metal source is a metal chloride or metal nitrate. In some embodiments, the metal source is one or more of aluminum chloride, magnesium chloride, barium chloride, calcium chloride, aluminum nitrate, magnesium nitrate, barium nitrate, calcium nitrate. In some embodiments, the ammonia source is one or more of urea and sodium amide, the mass of the first product in step S200 is n 1, and the mass of the metal source is n 2,0.01n1≤n2≤0.1n1. In some embodiments, the temperature of the water bath treatment in the step S200 is 60 ℃ to 90 ℃, the temperature of the drying treatment is 60 ℃ to 120 ℃, the time of the drying treatment is 5h to 15h, the temperature of the heat treatment is 350 ℃ to 550 ℃, and the time of the heat treatment is 3h to 12h. In some embodiments, the ball-milling process in the step S300 has a ball-to-material ratio of (5-20) of 1, a ball-milling rotation speed of 500-2500 rpm, a ball-milling time of 5-20 hours, a heat-treatment temperature of 350-550 ℃, a heat-treatment time of 5-12 hours, and a coating amount of metal fluoride of 0.5-5 wt.%. In some embodiments, the porosity of the porous carbon is greater than or equal to 50%, the pore size of the porous carbon is 10 nm-200 nm, and the mass fraction of silicon element in the