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Silicon-carbon composite negative electrode material and preparation method thereof, negative electrode sheet and preparation method thereof, and lithium ion battery

A negative electrode material, silicon carbon composite technology, applied in battery electrodes, secondary batteries, circuits, etc., can solve the problems of electrochemical performance and cycle life to be improved, volume expansion, poor cycle performance of lithium ion batteries, etc.

Active Publication Date: 2020-08-21
厦门高容纳米新材料科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the severe volume expansion (volume expansion of about 400%) of silicon materials during charge and discharge, the cycle performance of lithium-ion batteries is very poor.
In order to alleviate the volume expansion of silicon materials, silicon-carbon composite materials have been developed, and carbon is used to coat and modify silicon-based materials. However, the electrochemical performance and cycle life of existing silicon-carbon composite materials still need to be improved.

Method used

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  • Silicon-carbon composite negative electrode material and preparation method thereof, negative electrode sheet and preparation method thereof, and lithium ion battery
  • Silicon-carbon composite negative electrode material and preparation method thereof, negative electrode sheet and preparation method thereof, and lithium ion battery

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Embodiment approach

[0035] In the present invention, the carbon particle material whose surface is covered with a silicon dioxide layer can be graphite particle material or other carbon particle materials whose surface is covered with a silicon dioxide layer, which can be obtained commercially, or can be obtained according to existing There are various methods of preparation. According to a specific embodiment of the present invention, the graphite particle material coated with a silicon dioxide layer on the surface is prepared according to the following method: dispersing 10g of acid-treated graphite particles in 80-120mL of In ammonia water, add 1-3mL silane coupling agent for functionalization treatment for 3-8 hours, then add 80-120mL ethanol and dropwise add 20-40mL ethanol solution containing 1-5wt% silicon precursor material III, the silicon precursor material III is a compound that can be hydrolyzed into silicon dioxide, stirred at room temperature for 5-20 hours, separated from solid and...

Embodiment 1

[0052] S1. Disperse 1 g of polystyrene balls in 100 mL of ammonia water with a pH value of 10, add 2 mL of silane coupling agent (MPS) for functionalization treatment for 5 hours, add 100 mL of ethanol, drop in 30 mL of ethanol solution containing 6% TEOS, and stir at room temperature 10h, solid-liquid separation, the obtained solid product was dried at 60°C and then heated to 600°C and treated in air atmosphere for 30min to obtain hollow SiO 2 Microspheres.

[0053] The above hollow SiO 2 Microspheres were dispersed in 50mL of ethanol-water mixture (the volume ratio of ethanol and water was 2.3:1, the same below), and 1.5mL of ammonia water (concentration of 5wt%, the same below) and 0.5mL of ethylenediamine were added to mix evenly, and then added 0.5g of 3-aminophenol, 2mL of formaldehyde and 2mL of ethyl silicate were reacted with vigorous stirring (150rpm) at 40°C for 5h, centrifuged, and the resulting solid product was dried at 60°C for 2h to obtain a hollow surface wit...

Embodiment 2

[0057] S1, get 10g of acid-treated graphite particles and disperse them in 100mL of ammonia water with a pH of 8, add 2mL of silane coupling agent (MPS) for functionalization treatment for 5h, then add 100mL of ethanol and drop into 30mL of ethanol solution containing 3wt% TEOS, Stir at room temperature for 10h. Solid-liquid separation, and the obtained solid product is dried to obtain the graphite particle material (referred to as SiO2) that the surface is coated with a silicon dioxide layer. 2 / C microspheres).

[0058] The above SiO 2 / C microspheres are dispersed in 50mL ethanol-water mixture, add 2.5mL ammonia water and 0.5mL ethylenediamine and mix well, then add 1g 3-aminophenol, 2mL formaldehyde and 4mL ethyl silicate, stir vigorously at 40°C (30rpm ) reacted for 6 hours, centrifuged, and dried the obtained solid product at 60° C. for 3 hours to obtain a silica / phenolic composite material with a fractal structure on the graphite core surface.

[0059] S2. Take 2g of...

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Abstract

The invention belongs to the field of new energy materials, and relates to a silicon-carbon composite negative electrode material and a preparation method thereof, a negative electrode sheet and a preparation method thereof, and a lithium ion battery. The preparation method of the silicon-carbon composite negative electrode material comprises the following steps: S1, dispersing hollow silicon dioxide microspheres or a carbon particle material coated with a silicon dioxide layer on the surface, phenol and / or aminophenol, formaldehyde and a silicon precursor material into an alcohol-amine mixedaqueous solution; carrying out a violent stirring reaction at 20-90 DEG C for at least 20 minutes, carrying out solid-liquid separation, and drying to obtain a silicon dioxide / phenolic aldehyde composite material with a fractal structure on the surface; and S2, roasting the silicon dioxide / phenolic aldehyde composite material in the presence of magnesium powder and / or aluminum powder. When the silicon-carbon composite material is used as a lithium ion battery negative electrode material, the failure caused by volume change in the charging and discharging process can be well overcome, a good conductive network is maintained, the volume expansion is reduced, the first reversible capacity and the first coulombic efficiency are improved, the first cycle capacity loss is reduced, and the cyclestability is improved.

Description

technical field [0001] The invention belongs to the field of new energy materials, and in particular relates to a silicon-carbon composite negative electrode material, a negative electrode sheet, a preparation method thereof, and a lithium ion battery. Background technique [0002] At present, with the development of the new energy industry and the intensification of environmental pollution, the development of electric vehicles is becoming more and more rapid, and lithium-ion batteries with high capacity, high power and long cycle life have become urgently important. Lithium-ion batteries are the core of new energy vehicles and energy storage technologies at this stage, and the electrochemical performance of lithium-ion batteries mainly depends on the positive and negative electrodes of the battery. The key to lithium-ion batteries. Cathode materials have been extensively studied, and anode materials have also received more and more attention. Conventional lithium-ion batt...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/583H01M4/62H01M10/0525
CPCH01M4/362H01M4/583H01M4/625H01M4/386H01M10/0525Y02E60/10
Inventor 蒋玉雄
Owner 厦门高容纳米新材料科技有限公司
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