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Preparation method of hierarchical silicon-porous carbon composite negative electrode material for lithium battery

A negative electrode material, porous carbon technology, applied in battery electrodes, structural parts, secondary batteries, etc., can solve the problems of low ionic conductivity, low electronic conductivity of graphite, small specific surface area of ​​graphite, etc.

Active Publication Date: 2021-02-12
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] Mixing graphite and silicon can alleviate the structural instability of silicon, but the electronic conductivity of graphite is not high; at the same time, the specific surface area of ​​graphite is small and cannot effectively absorb electrolyte, so the ion conductivity is not high.

Method used

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  • Preparation method of hierarchical silicon-porous carbon composite negative electrode material for lithium battery
  • Preparation method of hierarchical silicon-porous carbon composite negative electrode material for lithium battery
  • Preparation method of hierarchical silicon-porous carbon composite negative electrode material for lithium battery

Examples

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Embodiment 1

[0023] Embodiment 1: A kind of preparation method of hierarchical structure silicon-porous carbon composite material, concrete steps are as follows:

[0024] (1) The multi-level structure silicon material (Si@C@CNT) was prepared by spray drying equipment. First, 1.5g of silicon nanoparticles, 100mg of carbon nanotubes, 1g of sucrose and 1.5g of P123 (EO 20 PO 70 EO 20 , wherein EO and PO are ethylene oxide and propylene oxide respectively) are dispersed in 200mL of ethanol and water mixed solvent (ethanol:water=3:1, volume ratio) to form mixed solution; The solution was converted into mist droplets and was blown by nitrogen (0.5L min -1 ) into a heated tube furnace (400°C) to condense into solid particles; finally, the solid particles collected with filter paper were placed in an argon atmosphere (0.4L min -1 ) at high temperature (900°C) for 1 h to form Si@C@CNT composite particles.

[0025] (2) The Si@C@CNT-porous carbon composite anode material was obtained by mechanic...

Embodiment 2

[0029] Example 2: The difference from Example 1 is that the Si@C@CNT-porous carbon composite negative electrode material is obtained by mechanically grinding the hierarchical silicon material Si@C@CNT and porous carbon at a mass ratio of 2:8. The other parts were the same as in Example 1, and assembled into a battery for electrochemical performance testing.

Embodiment 3

[0031] Example 3: The difference from Example 1 is that the Si@C@CNT-porous carbon composite negative electrode material is obtained by mechanically grinding the hierarchical silicon material Si@C@CNT and porous carbon at a mass ratio of 3:7. The other parts were the same as in Example 1, and assembled into a battery for electrochemical performance testing.

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Abstract

The invention relates to a preparation method of a multi-level structure silicon / porous carbon composite negative electrode material, which belongs to the field of materials for lithium batteries. Using a mechanical mixing method, the hierarchical structure silicon and the porous carbon are mixed as a composite negative electrode active material, wherein the mass ratio of the hierarchical structure silicon to the porous carbon is 0.11-0.43. Compared with graphite, the porous carbon used in the present invention can effectively increase the liquid absorption of the electrolyte on the one hand, and then accelerate the transmission of ions; on the other hand, the high conductivity of porous carbon accelerates the transmission of electrons; thereby obtaining a high-rate lithium battery Negative material.

Description

technical field [0001] The invention relates to a method for preparing a multi-level structure silicon-porous carbon composite negative electrode material for a lithium battery. The multi-level structure silicon-porous carbon composite negative electrode material obtained by this method can significantly increase the liquid absorption and electronic conductivity of the electrolyte, and then significantly increase the transmission speed of lithium ions and electrons, and obtain a high-rate lithium battery negative electrode material. Background technique [0002] In recent years, due to its high theoretical specific capacity (4200mAh g -1 ) are widely used as anode materials for lithium-ion batteries. However, due to its low electronic conductivity and the structural instability caused by the huge volume change during charging and discharging, silicon and graphite are generally mechanically mixed in a certain proportion as a composite negative electrode active material, at t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/36H01M4/583H01M4/62H01M10/0525H01M4/38
CPCH01M4/362H01M4/386H01M4/583H01M4/625H01M10/0525Y02E60/10
Inventor 贾希来朱晓
Owner UNIV OF SCI & TECH BEIJING