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CN-121601637-B - Low-strain silicon-carbon negative electrode material and preparation method thereof

CN121601637BCN 121601637 BCN121601637 BCN 121601637BCN-121601637-B

Abstract

The application discloses a low-strain silicon-carbon anode material and a preparation method thereof, wherein the preparation method comprises the steps of S100, synthesizing a MgV 2 O 6 product from a magnesium source and a vanadium source, S200, mixing porous carbon with the MgV 2 O 6 product to prepare a matrix material, and S300, carrying out vapor deposition on the outer surface and pore channels of the matrix material in inert gas by using a silane gas source and a carbon gas source to obtain the silicon-carbon anode material. According to the application, mgV 2 O 6 with a stable crystal structure is prepared by a magnesium source and a vanadium source, so that a rigid support is provided in the subsequent preparation process, and the use stability and the thermal stability are improved. The silicon-carbon negative electrode material with high use stability is prepared by vapor depositing a silane gas source and a carbon gas source on a matrix material to generate silicon-carbon active substances in situ, so that silicon atoms and carbon atoms form firm chemical bonding with carbon atoms on the surface of the matrix material, and stress generated during silicon expansion is absorbed by the internal structure of the silicon-carbon negative electrode material.

Inventors

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

Assignees

  • 银硅(宁波)科技有限公司

Dates

Publication Date
20260508
Application Date
20260128

Claims (9)

  1. 1. The preparation method of the low-strain silicon-carbon anode material is characterized by comprising the following steps of: S100, synthesizing a magnesium source and a vanadium source into a MgV 2 O 6 product; S200, mixing porous carbon with the MgV 2 O 6 product to prepare a matrix material, wherein the mass ratio of the porous carbon to the MgV 2 O 6 product is 1 (0.02-0.1); s300, performing vapor deposition on the outer surface and pore channels of the matrix material in inert gas by using a silane gas source and a carbon gas source to obtain a silicon-carbon anode material, and The step S200 is to ultrasonically disperse porous carbon and the MgV 2 O 6 product in water or ethanol and then dry to prepare a second intermediate product, and calcine the second intermediate product in inert gas to prepare a matrix material, wherein the calcination temperature is 500-700 ℃ and the calcination time is 1-4 h.
  2. 2. The preparation method according to claim 1, wherein at least one of the following conditions is satisfied: the magnesium source is one or more of magnesium acetate, magnesium nitrate, magnesium chloride, magnesium sulfate, magnesium isopropoxide and magnesium acetylacetonate; The vanadium source is one or more of vanadium pentoxide, ammonium metavanadate, vanadate, vanadyl sulfate and vanadyl acetylacetonate; the porous carbon is one or more of bio-based porous carbon, petroleum coke-based porous carbon or resin-based porous carbon.
  3. 3. The method according to claim 1, wherein the molar ratio of the magnesium source to the vanadium source is (1-10): 1-10.
  4. 4. A production method according to any one of claims 1 to 3, characterized in that 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 argon and helium.
  5. 5. The method according to claim 1, wherein the step S100 comprises the sub-steps of: s110, dissolving a magnesium source, a vanadium source and a complexing agent in water, heating and stirring for the first time to obtain a first mixture, wherein the complexing agent is one or more of citric acid, oxalic acid, tartaric acid, acetic acid, ethylene glycol, polyacrylate alcohol, ethylenediamine tetraacetic acid and glucose, the temperature of the first heating is 60-90 ℃, the time of the first heating is 0.1-3 h, and the molar ratio of the magnesium source, the vanadium source and the complexing agent is (1-10): (1-10); S120, heating the first mixture for the second time to obtain a second solid, wherein the temperature of the second heating is 400-500 ℃, and the time of the second heating is 0.1-3 hours; s130, calcining the second solid under air to obtain a MgV 2 O 6 product, wherein the calcining temperature is 500-700 ℃, and the calcining time is 1-10 h.
  6. 6. The method according to claim 1, wherein the step S100 comprises the sub-steps of: S110, grinding a magnesium source and a vanadium source, and then calcining for the first time in air to obtain a first intermediate product, wherein the treatment temperature of the first calcination is 500-700 ℃, the treatment time of the first calcination is 2-24 h, and the grinding time is 0.1-2 h; S120, grinding the first intermediate product, and then calcining for the second time in air to obtain a MgV 2 O 6 product, wherein the treatment temperature of the second calcination is 500-700 ℃, the treatment time of the second calcination is 1-24 h, and the grinding time is 0.1-2 h.
  7. 7. The method according to claim 1, wherein the step S100 comprises the sub-steps of: s110, uniformly mixing a magnesium source and a vanadium source, and pre-pressing the mixture into a sheet or a block under normal pressure to prepare a first mixture; S120, placing the first mixture into a boron nitride tube, and then loading the boron nitride tube into a pyrophyllite synthesis cavity to enable the first mixture to react at high temperature and high pressure to obtain a MgV 2 O 6 product, wherein graphite is used as a heating tube, pyrophyllite is used as an insulating tube in the pyrophyllite synthesis cavity, the reaction temperature is 800-1500 ℃, the reaction pressure is 0.1-20 GPa, and the reaction time is 0.1-2 h.
  8. 8. The method according to claim 4, wherein in the step S300, the volume flow ratio of the silane gas source to the inert gas is 1 (1-10), the volume flow ratio of the carbon gas source to the inert gas is 1 (1-10), the vapor deposition temperature is 500-1000 ℃, and the deposition time is 1-12 h.
  9. 9. The low-strain silicon-carbon anode material is characterized by being prepared by the preparation method of any one of claims 1-8, wherein the mass ratio of silicon element to carbon element in the silicon-carbon anode material is 1 (0.1-9).

Description

Low-strain 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 low-strain silicon-carbon negative electrode material 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 low-strain silicon-carbon negative electrode material and a preparation method thereof, which are beneficial to prolonging the service life of the silicon-carbon negative electrode material and further improving the structural stability and the service stability of the silicon-carbon negative electrode material in long-term circulation. The preparation method of the low-strain silicon-carbon anode material comprises the following steps of S100, synthesizing a MgV 2O6 product from a magnesium source and a vanadium source, S200, mixing porous carbon with the MgV 2O6 product to obtain a matrix material, and S300, carrying out vapor deposition on the outer surface and pore channels of the matrix material in inert gas by using a silane gas source and a carbon gas source to obtain the silicon-carbon anode material. In some embodiments, the preparation method meets at least one condition that the magnesium source is one or more of magnesium acetate, magnesium nitrate, magnesium chloride, magnesium sulfate, magnesium isopropoxide and magnesium acetylacetonate, the vanadium source is one or more of vanadium pentoxide, ammonium metavanadate, vanadate, vanadyl sulfate and vanadyl acetylacetonate, and the porous carbon is one or more of bio-based porous carbon, petroleum coke-based porous carbon or resin-based porous carbon. In some embodiments, the molar ratio of the magnesium source to the vanadium source is (1-10): (1-10), and the mass ratio of the porous carbon to the MgV 2O6 product is (0.02-0.1). In some embodiments, the method of making meets at least one condition that the silane source is one or more of monosilane, disilane, the carbon source is one or more of methane, ethane, propane, acetylene, propyne, and the inert gas is one or more of nitrogen, argon, helium. In some embodiments, the step S100 comprises the substeps of S110, dissolving a magnesium source, a vanadium source and a complexing agent in water, heating and stirring for the first time to obtain a first mixture, wherein the complexing agent is one or more of citric acid, oxalic acid, tartaric acid, acetic acid, ethylene glycol, polyacrylate alcohol, ethylenediamine tetraacetic acid and glucose, the temperature of the first time is 60-90 ℃, the time of the first time is 0.1-3 h, the molar ratio of the magnesium source, the vanadium source and the complexing agent is (1-10): (1-10), S120, heating for the second time to obtain a second sol