CN-121617947-B - Titanium doped silicon carbon negative electrode material and preparation method thereof

CN121617947BCN 121617947 BCN121617947 BCN 121617947BCN-121617947-B

Abstract

The application discloses a titanium doped silicon carbon negative electrode material and a preparation method thereof, the preparation method comprises the steps of mixing a carbon source, a titanium source and a pore-forming agent in water in a liquid phase, freeze-drying to obtain a first product comprising titanium oxide, calcining the first product in reducing gas to obtain Ti 4 O 7 doped porous carbon, and performing vapor deposition on the outer surface and pore canal of the Ti 4 O 7 doped porous carbon in inert gas by using a silane gas source and a carbon gas source to obtain the silicon carbon negative electrode material. According to the application, the carbon source, the titanium source and the pore-forming agent are mixed in water to generate the titanium oxide, and the titanium oxide is calcined by using the reducing gas, so that the titanium oxide is reduced into Ti 4 O 7 with metal-level conductivity and high catalytic activity, and the rapid electron transmission and the structural stability are facilitated. And a silane gas source and a carbon gas source are vapor deposited on the Ti 4 O 7 doped porous carbon to generate silicon-carbon active substances in situ, so that the structural stability and the conductivity are improved.

Inventors

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

Assignees

银硅(宁波)科技有限公司

Dates

Publication Date: 20260508
Application Date: 20260202

Claims (7)

1. The preparation method of the titanium doped silicon carbon anode material is characterized by comprising the following steps: s100, mixing a carbon source, a titanium source and a pore-forming agent in water in a liquid phase, and freeze-drying to obtain a first product comprising titanium oxide, wherein the mass ratio of the carbon source to the titanium source to the pore-forming agent is 1 (0.01-0.5) (1-10), the freeze-drying treatment temperature is-30 ℃ to-20 ℃, and the treatment time is 12-36 h; S200, calcining the first product in reducing gas to obtain Ti 4 O 7 doped porous carbon, wherein the calcining treatment temperature is 800-1000 ℃ and the treatment time is 1-5 h, the reducing gas is mixed gas of hydrogen and shielding gas, and the volume fraction of the hydrogen in the mixed gas of the hydrogen and the shielding gas is 2-10%; And S300, performing vapor deposition on the outer surface and pore channels of the Ti 4 O 7 doped porous carbon in an inert atmosphere by using a silane gas source and a carbon gas source to obtain the silicon-carbon anode material.
2. The preparation method according to claim 1, wherein at least one of the following conditions is satisfied: The carbon source is one or more of phenolic resin, formaldehyde resin, urea resin, furfural resin, furfuryl ketone resin, acrylic resin, glucose, sucrose and citric acid; The titanium source is one or more of tetraisopropyl titanate, tetrabutyl titanate, titanyl sulfate, titanium isopropoxide and titanium ethoxide; the pore-forming agent is one or more of sodium chloride, potassium chloride, ammonium bicarbonate, urea, polyethylene glycol and polyacrylic acid.
3. The method according to claim 1, wherein the shielding gas is argon and/or nitrogen.
4. 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 atmosphere is one or more of nitrogen, argon and helium.
5. The method according to any one of claims 1 to 4, wherein in the step S300, the volume flow ratio of the silane gas source to the inert atmosphere is 1 (1 to 10), the volume flow ratio of the carbon gas source to the inert atmosphere is 1 (1 to 10), the vapor deposition temperature is 500 ℃ to 1000 ℃ and the deposition time is 1h to 12h.
6. The method according to claim 1, wherein the step S300 comprises the sub-steps of: s310, immersing the Ti 4 O 7 doped porous carbon into deionized water for stirring and washing to obtain a second product, wherein the mass ratio of the Ti 4 O 7 doped porous carbon to the deionized water is1 (30-60), and performing vacuum drying on the second product to obtain a third product, wherein the vacuum drying treatment temperature is 50-100 ℃, and the treatment time is 10-24 hours; And S320, performing vapor deposition on the outer surface of the third product and the pore canal by using a silane gas source and a carbon gas source in an inert atmosphere to obtain the silicon-carbon anode material.
7. The titanium-doped silicon-carbon anode material is characterized by being prepared by the preparation method of any one of claims 1-6, wherein the mass ratio of silicon element to carbon element in the silicon-carbon anode material is 1 (0.1-9).

Description

Titanium doped 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 titanium doped 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 titanium doped 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, optimizing the ion transmission path and the reaction kinetic performance and further improving the intrinsic conductivity of the silicon-carbon anode material. The technical scheme includes that the preparation method of the titanium-doped silicon-carbon negative electrode material comprises the steps of mixing a carbon source, a titanium source and a pore-forming agent in water in a liquid phase, freeze-drying to obtain a first product comprising titanium oxide, calcining the first product in reducing gas to obtain Ti 4O7 -doped porous carbon, and performing vapor deposition on the outer surface and pore channels of the Ti 4O7 -doped porous carbon in inert gas by using a silane source and a carbon source to obtain the silicon-carbon negative electrode material. In some embodiments, the preparation method meets at least one condition that the carbon source is one or more of phenolic resin, formaldehyde resin, urea resin, furfural resin, furfuryl ketone resin, acrylic resin, glucose, sucrose and citric acid, the titanium source is one or more of tetraisopropyl titanate, tetrabutyl titanate, titanyl sulfate, titanium tetrachloride, titanium isopropoxide and titanium ethoxide, and the pore-forming agent is one or more of sodium chloride, potassium chloride, ammonium bicarbonate, urea, polyethylene glycol and polyacrylic acid. In some embodiments, the mass ratio of the carbon source to the titanium source to the pore-forming agent is1 (0.01-0.5): 1-10. In some embodiments, the reducing gas is hydrogen or a mixed gas of hydrogen and a shielding gas, wherein the volume fraction of the hydrogen in the mixed gas of the hydrogen and the shielding gas is 2% -10%, and the shielding gas is argon and/or nitrogen. 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, 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 ℃