Preparation method of silicon-carbon composite negative electrode material of lithium ion battery and application of silicon-carbon composite negative electrode material

A lithium-ion battery, silicon-carbon composite technology, applied in battery electrodes, secondary batteries, circuits, etc., can solve the problem of nano-silicon falling off, and achieve high specific capacity, high initial charge and discharge efficiency, and excellent cycle stability.

Active Publication Date: 2015-02-18
广东羚光新材料股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method solves the problem that nano-silicon is easy to agglomerate because of its small particle size, high specific surface energy, and exhibits excellent battery performance. However, this method only uses silane coupling a

Method used

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  • Preparation method of silicon-carbon composite negative electrode material of lithium ion battery and application of silicon-carbon composite negative electrode material
  • Preparation method of silicon-carbon composite negative electrode material of lithium ion battery and application of silicon-carbon composite negative electrode material
  • Preparation method of silicon-carbon composite negative electrode material of lithium ion battery and application of silicon-carbon composite negative electrode material

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Experimental program
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Embodiment 1

[0048] In the presence of an ethanol dispersion medium, use a grinder to grind silicon, and add maleic acid to the silicon grinding solution to control the pH value of the silicon grinding dispersion to 5.8 and the mass solid content to 10.3%, and set aside. The average particle size of the silicon particles in the silicon polishing liquid is 150nm.

[0049] Adding 121.3g mass solid content is 10.3% nano-silicon dispersion liquid and 12.5g silane coupling agent γ-methacryloxypropyltrimethoxysilane (trade name: KH570) in the glass reactor, then successively Add 12.5g of styrene solution with 0.54g of dibenzoyl peroxide dissolved in it and 2.5g of dodecyl mercaptan (TDM) into the reaction kettle, set the temperature at 73°C, stir at 150rpm, and keep the temperature for 10h. After cooling to room temperature, add 175g of styrene monomer to the solution, mix and stir, then purify and remove the ethanol in the mixed solution to obtain a hydrophobically treated nano-silicon dispersi...

Embodiment 2

[0054] (1) prepare nano-silicon dispersion liquid with embodiment one;

[0055] (2) Add 364.1g of nano-silicon dispersion liquid and 37.5g of silane coupling agent γ-methacryloxypropyl trimethoxysilane (trade name: KH570) that step (1) obtains in glass reactor, then 1.12g dibenzoyl peroxide (BPO) was gently stirred and dissolved in 37.5g styrene and added to the reactor, and finally 0.75g dodecyl mercaptan (TDM) was added to the reactor. At 73° C. and a stirring speed of 150 rpm, the reaction was kept for 10 h, and then cooled to room temperature. Add 175g styrene to this solution and mix and stir, then purify and remove the ethanol of this mixed solution to get the nano-silicon dispersion liquid dispersed in styrene, and then complete the surface modification of nano-silicon, adopt GPC (Gel Permeation Chromatography), measuring the weight-average molecular weight of the surface polymer of modified nano-silicon is 15000.

[0056] Take by weighing 13.18g dibenzoyl peroxide an...

Embodiment 3

[0060] (1) prepare nano-silicon dispersion liquid with embodiment one;

[0061] (2) Add 364.1g of nano-silicon dispersion liquid obtained in step (1) and 37.5g of silane coupling agent γ-methacryloxypropyl trimethoxysilane (KH570) into the reactor, and then 0.56g of Stir and dissolve dibenzoyl oxide (BPO) into 18.75g of styrene, add 1.88g of dodecyl mercaptan (TDM) into the reaction kettle, set the reaction temperature at 73°C, keep the temperature for 15h, and then Cool to room temperature. Then add 175g of styrene monomer to this solution, mix and stir, then purify and remove the ethanol of this mixed solution to obtain nano-silicon dispersion liquid dispersed in styrene, and then complete the surface modification of nano-silicon, using GPC (Gel Permeation Chromatography), the weight average molecular weight of the surface polymer was determined to be 8500.

[0062] Take by weighing 13.18g dibenzoyl peroxide (BPO) and gently stir and dissolve in 75g acrylonitrile (AN), and...

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Abstract

The invention provides a preparation method of a silicon-carbon composite negative electrode material of a lithium ion battery. According to the preparation method, an existing silane coupling agent treatment technology is combined and a polymer cladding layer is formed on the surface of nano silicon by dispersion and polymerization processes; then nano silicon dispersion liquid with the polymer cladding layer on the surface is dispersed into an aromatic vinyl monomer; micro-molecular organic alcohol in the dispersion liquid is thoroughly removed by purification treatment so as to finish a nano silicon surface modification process; a condensation product is prevented from being generated by the modification method, and technical supports are provided for formation of oil-in-water type emulsion by micro-suspension polymerization; the problems that the nano silicon has high hydrophily and can easily overflow from an oil phase or a polymer in the dispersion and polymerization processes are solved; and the problems that the nano silicon can be united easily due to small granularity and high specific surface energy are solved. The silicon-carbon composite negative electrode material prepared by the method has high specific capacity (being more than 680Ah/g), high first-time charging and discharging efficiency (being more than 87%) and good circulating stability.

Description

technical field [0001] The invention relates to the field of lithium-ion batteries, in particular to a method for preparing a silicon-carbon composite negative electrode material for lithium-ion batteries. Background technique [0002] At present, the anode materials of commercial lithium-ion batteries use graphite-like carbon materials, which have the advantages of low lithium intercalation / deintercalation potential, suitable reversible capacity, rich resources, and low price. They are ideal lithium-ion battery anode materials. However, its theoretical specific capacity is only 372mAh / g, which cannot meet the growing demand for high-energy portable mobile power supplies, thus limiting its application in lithium-ion batteries. Among many alternative materials, silicon has become one of the most potential materials to replace graphite anode materials because of its extremely high specific capacity (theoretical value 4200mAh / g). However, silicon-based negative electrode mater...

Claims

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Application Information

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IPC IPC(8): H01M4/1395H01M10/0525
CPCH01M4/1395H01M10/0525Y02E60/10
Inventor 刘祥刘凡东
Owner 广东羚光新材料股份有限公司
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