Preparation method for silicon-carbon composite material

A silicon-carbon composite material, metal silicon technology, applied in nanotechnology, electrical components, electrochemical generators for materials and surface science, etc., can solve problems such as poor capacity, affecting charge-discharge performance, and poor cycle performance, etc. Achieve energy savings, improved capacity and cycle performance, and improved mobility

Active Publication Date: 2017-07-07
陕西六元碳晶科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The invention provides a method for preparing a silicon-carbon composite material, which solves the problems in traditional silicon-carbon composite materials that the charging and discharging performance is affected by silicon expansion, the cycle performance is poor, and the capacity is poor

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] The preparation method of the silicon-carbon composite material provided in Example 1 of the present invention comprises the following steps:

[0018] Step 1: Evenly mix metal silicon with a purity of 4N and a particle size of 2 μm with graphite powder with a purity of 3N and a particle size of 325 mesh, and the molar ratio of the metal silicon to the graphite powder is 0.1:100;

[0019] Step 2: Place the evenly mixed metal silicon and graphite powder in the graphite crucible and put it into a closed furnace filled with nitrogen atmosphere protection for heat treatment;

[0020] Step 3: When the temperature in the kiln rises to 2200°C, keep the constant temperature for 20 minutes. During the process of constant temperature and heat preservation, adjust the pressure in the kiln to keep the positive pressure and negative pressure between 0.1MPa-100Pa for periodic pulsation changes. The cycle of negative pressure pulsation is 5 minutes, and the silicon-carbon composite mat...

Embodiment 2

[0023] The preparation method of the silicon-carbon composite material provided in Example 2 of the present invention comprises the following steps:

[0024] Step 1: uniformly mix metallic silicon with a purity of 5N and a particle size of 5 μm with graphite powder with a purity of 4N and a particle size of 600 mesh, and the molar ratio of the metallic silicon to the graphite powder is 2:100;

[0025] Step 2: Place the evenly mixed metal silicon and graphite powder in the graphite crucible and put it into a closed furnace filled with nitrogen atmosphere protection for heat treatment;

[0026] Step 3: When the temperature in the kiln rises to 2355°C, keep the constant temperature for 40 minutes. During the process of constant temperature and heat preservation, adjust the pressure in the kiln to keep the positive pressure and negative pressure between 0.1MPa-100Pa for periodic pulsation changes. The period of the negative pressure pulsation change is 1min, and the silicon-carbon...

Embodiment 3

[0029] The preparation method of the silicon-carbon composite material provided in Example 3 of the present invention comprises the following steps:

[0030] Step 1: Evenly mix metallic silicon with a purity of 4N and a particle size of 10 μm with graphite powder with a purity of 5N and a particle size of 800 mesh, and the molar ratio of the metallic silicon to the graphite powder is 5:100;

[0031] Step 2: Place the evenly mixed metal silicon and graphite powder in the graphite crucible and put it into a closed furnace filled with nitrogen atmosphere protection for heat treatment;

[0032] Step 3: When the temperature in the kiln rises to 2400°C, keep the constant temperature for 60 minutes. During the process of constant temperature and heat preservation, adjust the pressure in the kiln to keep the positive pressure and negative pressure between 0.1MPa-100Pa for periodic pulsation changes. The cycle of negative pressure pulsation is 10 minutes, and the silicon-carbon composi...

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Abstract

The invention discloses a preparation method for a silicon-carbon composite material, and relates to the synthesis field of a silicon-carbon negative electrode material. The preparation method comprises the steps of performing uniform mixing on metal silicon and graphite powder based on a certain proportion; putting the uniformly-mixed metal silicon and graphite powder into a graphite crucible and then putting into a sealed furnace kiln to be subjected to heating treatment; performing constant-temperature heat preservation for 20-60min when the temperature in the furnace kiln is heated to 2,200-2,400 DEG C; adjusting the pressure in the furnace kiln in the constant-temperature heat preservation process; maintaining positive pressure and negative pressure to be subjected to periodic pulsation change within 0.1MPa-100Pa, and after performing the constant-temperature heat preservation, obtaining the silicon-carbon composite material. According to the silicon-carbon composite material prepared by the invention, the capacity and cycling performance of the graphite negative electrode material are effectively improved; and meanwhile, by controlling a silicon filling agent, influence of silicon expansion in charging and discharging is lowered, energy can be saved effectively, and environment pollution is relieved.

Description

technical field [0001] The invention relates to the field of synthesis of silicon-carbon negative electrode materials, in particular to a method for preparing a silicon-carbon composite material. Background technique [0002] Carbon material is currently the most widely used material for the negative electrode of lithium-ion batteries. It not only has mature application technology and high capacity, but also has excellent cycle performance, high Coulombic efficiency and stable discharge voltage platform, and is compatible with solvents. Good, it can provide high and stable working voltage for lithium batteries, good high and low temperature performance and safety performance. The theoretical specific capacity of silicon materials is very high, and the energy density can be increased by more than 200% after silicon-carbon compounding, which can not only meet the capacity requirements of portable high-power power supplies, but also meet the high power requirements of hybrid el...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/587H01M10/0525B82Y30/00
CPCB82Y30/00H01M4/362H01M4/386H01M4/587H01M10/0525Y02E60/10
Inventor 陈跃峰朱振明陈怡璇杨辉朱君宇
Owner 陕西六元碳晶科技有限公司
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