Surface-modified silicon-carbon composite and preparing method and application thereof

A silicon-carbon composite material and surface modification technology, which is applied in the fields of nanotechnology, active material electrodes, and electrical components for materials and surface science. and other problems, to achieve the effect of improving electrochemical performance, low cost, and improving electrical conductivity

Inactive Publication Date: 2019-01-29
ZOTYE INT AUTOMOBILE TRADING CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, nano-silicon is mainly obtained by crushing silicon, which is costly and complicated, and is not conducive to large-scale production.
Although nanonization and compounding can improve the cycle performance of silicon-based negative electrodes, it is still a big challenge to realize the simple and large-scale preparation of nano-silicon-based materials.
In addition, unlike graphite anodes, it is difficult for silicon-based anodes to form a stable SEI film. The residual HF in the electrolyte also has a corrosive effect on silicon, so it is necessary to protect the surface of silicon to form an artificial SEI film. In addition, the electrical conductivity of silicon Low, need to introduce conductive agent
[0004] The existing technology uses additives in the electrolyte to form the SEI film. Too many additives will affect the performance of the battery, and too few additives will gradually be consumed during use.

Method used

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  • Surface-modified silicon-carbon composite and preparing method and application thereof
  • Surface-modified silicon-carbon composite and preparing method and application thereof
  • Surface-modified silicon-carbon composite and preparing method and application thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0044]A method for preparing a surface-modified silicon-carbon composite material, comprising the following steps:

[0045] 1) Calcining diatomite in air at 800°C for 2 hours, then washing the calcined product with 6mol / L hydrochloric acid for 12 hours, and then washing it with water for 5 times to obtain pure silicon oxide;

[0046] 2) Then the pure silicon oxide, magnesium powder and sodium chloride prepared in step 1) are mixed by ball milling, the molar ratio of magnesium powder and pure silicon oxide is 2:1, and the weight ratio of sodium chloride to pure silicon oxide is 6:1; The ball milling speed is 180r / min, and the ball milling time is 10 hours to obtain a mixture;

[0047] 3) Put the mixture prepared in step 2) in a magnetic boat, then put polypropylene in another magnetic boat, the weight ratio of polypropylene to pure silicon oxide is 1:1, and place the two magnetic boats side by side in the tube furnace In the process, argon gas was introduced to carry out simul...

Embodiment 2

[0059] A method for preparing a surface-modified silicon-carbon composite material, comprising the following steps:

[0060] 1) Calcining kaolin in air at 800°C for 2 hours, then washing the calcined product with 6mol / L hydrochloric acid for 12 hours, and washing it with deionized water for 5 times to obtain pure silicon oxide;

[0061] 2) Then the pure silicon oxide, magnesium powder and potassium chloride prepared in step 1) are mixed by ball milling, the molar ratio of magnesium powder and pure silicon oxide is 2.1:1, and the weight ratio of potassium chloride and pure silicon oxide is 8:1; The ball milling speed is 180r / min, and the ball milling time is 10 hours to obtain a mixture;

[0062] 3) Put the mixture prepared in step 2) in a magnetic boat, then put polyethylene in another magnetic boat, the weight ratio of polyethylene to pure silicon oxide is 1:1, and place the two magnetic boats side by side in the tube furnace In the process, argon gas is introduced to carry ...

Embodiment 3

[0068] A method for preparing a surface-modified silicon-carbon composite material, comprising the following steps:

[0069] 1) Diopside was first calcined in air at 800°C for 2 hours, then the calcined product was washed with 6mol / L hydrochloric acid for 12 hours, and then washed 5 times with deionized water until neutral to obtain pure silica;

[0070] 2) Then the pure silicon oxide, magnesium powder and sodium chloride prepared in step 1) are mixed by ball milling, the molar ratio of magnesium powder and pure silicon oxide is 2.1:1, and the weight ratio of sodium chloride to pure silicon oxide is 10:1; The ball milling speed is 180r / min, and the ball milling time is 10 hours to obtain a mixture;

[0071] 3) Place the mixture prepared in step 2) in a magnetic boat, then place polyvinyl chloride in another magnetic boat, the weight ratio of polyvinyl chloride to pure silicon oxide is 1:1, and place the two magnetic boats side by side in the tube In the type furnace, argon ga...

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Abstract

The invention discloses a surface-modified silicon-carbon composite and a preparing method and application thereof. The method includes the steps of firstly, conducting high-temperature treatment on commercial raw materials containing silicon oxide, and conducting pickling to clean away impurities to obtain silicon oxide; secondly, conducting magnesium thermal reduction reaction on the silicon oxide to obtain nanometer silicon, synchronously conducting carbon wrapping to obtain a silicon-carbon nanometer material, and combining the nanometer silicon carbon and fluoride through ball-milling toobtain the silicon-base composite. Compared with the prior art, the method is simple in process, low in energy consumption and beneficial for industrial production. The silicon-carbon composite modified by the prepared surface fluoride has high capacity, high primary coulombic efficiency and excellent circulating performance.

Description

technical field [0001] The invention relates to the technical field of energy storage batteries, in particular to a surface-modified silicon-carbon composite material and a preparation method and application thereof. Background technique [0002] Lithium-ion batteries are now widely used in mobile electronic devices, such as smartphones, laptops, etc., and have huge markets in grid energy storage, electric vehicles. However, with the large-scale use of lithium-ion batteries in electric vehicles, traditional graphite-based anodes cannot meet the increasing requirements of high energy density for power batteries. Compared with graphite-based negative electrodes, the theoretical capacity of silicon-based negative electrodes reaches 4200mAh / g, which has important application prospects. [0003] However, in the process of forming the lithium-silicon alloy, the volume expansion is as high as 300%, which seriously affects the cycle life of the material. At present, measures to im...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/0525B82Y30/00
CPCB82Y30/00H01M4/366H01M4/386H01M4/625H01M4/628H01M10/0525H01M2004/021H01M2004/027Y02E60/10
Inventor 刘慧军郑东牛丽媛金源谢健郭永斌
Owner ZOTYE INT AUTOMOBILE TRADING CO LTD
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