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Preparation method of silicon-carbon composite negative electrode material, and prepared negative electrode material

A negative electrode material, silicon carbon composite technology, applied in the field of lithium ion batteries, can solve the problems of uneven coating, incomplete coating, poor cycle stability, etc.

Inactive Publication Date: 2021-05-07
HUNAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the existing carbon-silicon composite materials have the defects of poor shell structure strength and poor cycle stability.
The reason is that the shell structure of the conventional silicon-carbon material is only prepared by simple coating, so there will be uneven or incomplete coating, resulting in the exposed silicon material and the frequent contact between the silicon material and the electrolyte. The contact causes the volume to change repeatedly, causing the shell to collapse; the second is that there is no buffer void channel designed for the volume expansion of silicon

Method used

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  • Preparation method of silicon-carbon composite negative electrode material, and prepared negative electrode material
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  • Preparation method of silicon-carbon composite negative electrode material, and prepared negative electrode material

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Embodiment 1

[0043] A method for preparing a silicon-carbon composite negative electrode material and the prepared negative electrode material, comprising the following steps:

[0044] 1) Micron-sized industrial silicon powder is washed with deionized water, dispersed and dried with sodium carboxymethylcellulose dispersant, crushed by a crusher, and classified on a jet mill equipped with an air cyclone to obtain 0.5-3µm particles Precursor silicon powder;

[0045]2) Put step 1) precursor silicon powder in a rotary furnace, raise the temperature to 800°C, feed a mixed gas containing water vapor and argon, the content of water vapor is 10%, the content of argon is 90%, and the calcination process is 6.5 h, prepared Si / SiO 2 composite powder;

[0046] 3) At room temperature, add polyvinyl alcohol to a certain amount of deionized water (solid content 0.01g / mL), stir and heat up to 95°C, and obtain a transparent glue after constant temperature for 0.5h;

[0047] 4) Combine step 2) Si / SiO 2 ...

Embodiment 2

[0076] A method for preparing a silicon-carbon composite negative electrode material and the prepared negative electrode material, comprising the following steps:

[0077] 1) Micron-sized industrial silicon powder is washed with deionized water, dispersed and dried with sodium dodecylbenzenesulfonate dispersant, crushed by a crusher, and classified on a jet mill equipped with an air cyclone to obtain 0.5- 3µm precursor silicon powder;

[0078] 2) Put step 1) precursor silicon powder in a rotary furnace, raise the temperature to 800°C, feed a mixed gas containing water vapor, oxygen and argon, the water vapor content is 8%, the oxygen content is 2%, and calcined 9.75h, prepared Si / SiO 2 composite powder;

[0079] 3) At room temperature, add starch to deionized water (solid content 0.01g / mL), stir and heat up to 95°C, and keep the temperature for 0.5h to obtain a transparent glue;

[0080] 4) Combine step 2) Si / SiO 2 The composite powder is added to the transparent glue solu...

Embodiment 3

[0087] A high-performance silicon-carbon composite negative electrode material and a preparation method thereof, comprising the following steps:

[0088] 1) Micron-sized industrial silicon powder is washed with deionized water, dispersed and dried with oleylamine dispersant, crushed by a crusher, and classified on a jet mill equipped with an air cyclone to obtain a precursor silicon powder of 0.5-3 µm ;

[0089] 2) Put step 1) precursor silicon powder in a rotary furnace, raise the temperature to 800°C, feed a mixed gas containing water vapor, oxygen and argon, the water vapor content is 8%, the oxygen content is 2%, and calcined 9.75h, prepared Si / SiO 2 composite powder;

[0090] 3) At room temperature, add polyacrylic acid to deionized water (solid content 0.01g / mL), stir and heat up to 95°C, and obtain a transparent glue after constant temperature for 0.5h;

[0091] 4) Combine step 2) Si / SiO 2 The composite powder is added to the transparent glue solution in step 3), wh...

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Abstract

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a preparation method of a silicon-carbon composite negative electrode material, and the prepared negative electrode material. Micron-scale industrial silicon powder is treated in an oxidizing atmosphere to obtain nano-scale silicon particles, and the electronic conductivity of the material is improved through the first carbon source, so the utilization rate of the silicon particles is increased; the second carbon source constructs a cavity structure, the structural stability of the silicon particles is kept, the third carbon source enhances the connectivity between primary particles, and a complete carbon layer protection shell is constructed, so the structural integrity of the material is improved; and finally, large particles of ten microns are obtained, so that the method is more favorable for industrial production, has the advantages of nanoscale in a laboratory, and also has industrial application conditions.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a method for preparing a silicon-carbon composite negative electrode material and the prepared negative electrode material. [0002] technical background [0003] Lithium-ion batteries are widely used in rail transit, electronic communications, wearable devices and other industries because of their high specific energy, long cycle life, low self-discharge efficiency, and good safety performance. Among them, the negative electrode material is a key factor affecting the performance of lithium-ion batteries, and the existing lithium-ion battery negative electrode materials mainly use natural graphite, artificial graphite, and intermediate graphite materials. After years of research, the performance of graphite-based anode materials is basically close to the theoretical specific capacity of 372mAh / g, but it still cannot meet the actual needs of lithium-ion ba...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/583H01M4/62H01M10/0525H01M10/42B82Y30/00B82Y40/00
CPCB82Y30/00B82Y40/00H01M4/366H01M4/386H01M4/583H01M4/625H01M10/0525H01M10/4235Y02E60/10
Inventor 韩飞孔泥早刘金水
Owner HUNAN UNIV
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