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Silicon-carbon composite cathode material with three-dimensional preformed hole structure and preparation method thereof

A silicon-carbon composite and negative electrode material technology, applied in structural parts, battery electrodes, electrical components, etc., can solve the problems of difficult process control, complex CVD process, and easy damage to the carbon shell, and achieve the effect of structural stability.

Active Publication Date: 2012-08-01
湖南宸宇富基新能源科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Liu et al. used benzene as raw material gas to synthesize surface carbon-coated silicon-based materials by CVD method [W.R.Liu, J.H.Wang, H.C.Wu, et al..J.Electrochem.Soc., 2005, 152(9): A1719- A1725], but the coated carbon shell is easily destroyed after repeated cycles, and the CVD process is complicated, the process is difficult to control, and it is difficult to obtain uniform products, which is not conducive to large-scale production
[0007] The applicant of this patent believes that the reason why the current silicon-carbon composite materials cannot completely solve the problem of silicon expansion during charging and discharging is that the carbon component in it does not really play a role in stabilizing the structure.

Method used

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  • Silicon-carbon composite cathode material with three-dimensional preformed hole structure and preparation method thereof
  • Silicon-carbon composite cathode material with three-dimensional preformed hole structure and preparation method thereof
  • Silicon-carbon composite cathode material with three-dimensional preformed hole structure and preparation method thereof

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Experimental program
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Effect test

Embodiment 1

[0037] Step 1: Surface modification of silicon particles

[0038] Take 1g of nano-silicon particles with an average particle size of 30nm, add them to 100mL of absolute ethanol solution, and disperse them ultrasonically for 30min, wherein the ultrasonic power is 200W and the ultrasonic frequency is 45kHz to form a uniform silicon particle suspension; place the silicon particle suspension in Stir in a stirrer, add 0.2 g of cetyltrimethylammonium bromide at a stirring intensity of 1000 r / min, and continue stirring for 2 hours to obtain a surface-modified high-capacity silicon particle dispersion;

[0039] Step 2: Silica-coated silicon particles

[0040] Take 50mL of the silicon particle dispersion after the first step of modification treatment. During the ultrasonic process, use ammonia water as the pH regulator to adjust the pH of the solution to 9 to form a uniformly dispersed alkaline suspension; then slowly add 21mL orthosilicon In the mixed solution of ethyl orthosilicate ...

Embodiment 2

[0050] Step 1: Surface modification of silicon particles

[0051] Take 1g of nano-silicon particles with an average particle size of 80nm, add them to 100mL of absolute ethanol solution, and disperse them ultrasonically for 30 minutes, wherein the ultrasonic power is 200W and the ultrasonic frequency is 45kHz to form a uniform suspension of silicon particles; Stir in a stirrer, add 0.2 g of cetyltrimethylammonium bromide at a stirring intensity of 1000 r / min, and continue stirring for 2 hours to obtain a surface-modified high-capacity silicon particle dispersion.

[0052] Step 2: Silica-coated silicon particles

[0053] Take 50mL of the silicon particle dispersion after the first step of modification treatment. During the ultrasonic process, use ammonia water as the pH regulator to adjust the pH of the solution to 9 to form a uniformly dispersed alkaline suspension; then slowly add 22mL orthosilicon In the mixed solution of ethyl orthosilicate and ethanol, wherein the volume ...

Embodiment 3

[0061] Step 1: Surface modification of silicon particles

[0062] Take 1g of nano-silicon particles with an average particle size of 30nm, add them to 100mL of absolute ethanol solution, and disperse them ultrasonically for 30min, wherein the ultrasonic power is 200W and the ultrasonic frequency is 45kHz to form a uniform silicon particle suspension; place the silicon particle suspension in Stir in a stirrer, under the stirring intensity of 1000r / min, add 2mL KH550 type silane coupling agent, continue to stir and react for 2h, and obtain a surface-modified high-capacity silicon particle dispersion.

[0063] Step 2: Silica-coated silicon particles

[0064] Take 50mL of the silicon particle dispersion after the first step of modification treatment. During the ultrasonic process, use ammonia water as the pH regulator to adjust the pH of the solution to 9 to form a uniformly dispersed alkaline suspension; then slowly add 21mL orthosilicon In the mixed solution of ethyl orthosilic...

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Abstract

The invention discloses a silicon-carbon composite cathode material with a three-dimensional preformed hole structure and a preparation method thereof. According to the composite cathode material, a carbon material having high electric conductivity and a stable structure is used as a matrix for dispersedly containing high-volume silicon particles, and proper three-dimensional expansion spaces are reserved around one or several silicon particles. The preparation method comprises the following steps of: carrying out surface modification on the silicon particles; coating the silicon particles by silicon dioxide; coating the silicon dioxide / silicon composite particles by carbon source precursors; carrying out high-temperature carbonization treatment; and removing a silicon dioxide template, and the like. When the composite material prepared by the preparation method is used for a lithium ion battery, the reversible specific capacity is high, and the cycle performance is excellent. The silicon-carbon composite cathode material has the advantages of simple preparation process and wide raw material resource and is suitable for industrial production.

Description

technical field [0001] The invention relates to a silicon-carbon composite negative electrode material for lithium ion batteries and a preparation method thereof, in particular to a silicon-carbon composite negative electrode material with a three-dimensional reserved hole structure and a preparation method thereof. Background technique [0002] At present, graphite-like carbon materials are widely used as anode materials in commercial lithium-ion batteries, and their theoretical capacity is low (372mAh / g). The research and application of high-capacity anode materials has become the key to improving the performance of lithium-ion batteries. Silicon material is considered to be one of the ideal candidates to replace graphite anode materials due to its extremely high theoretical lithium storage capacity (4200mAh / g), good safety performance and abundant resources. However, the biggest problem when silicon is used as the negative electrode is that lithium ions cause a huge volum...

Claims

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Application Information

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IPC IPC(8): H01M4/38
CPCY02E60/12Y02E60/10
Inventor 杨娟周向阳唐晶晶邹幽兰王松灿谢静马路路伍上元刘宏专
Owner 湖南宸宇富基新能源科技有限公司
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