Lithium ion battery anode material and preparation method thereof

A technology for lithium ion batteries and negative electrode materials, applied in battery electrodes, batteries, secondary batteries, etc., can solve the problems of unsuitable preparation process, poor electrode cycle performance, poor structural stability, etc., and achieve good ion/electronic conduction. effect, improving electrical conductivity and structural stability, and structural stability

Active Publication Date: 2015-11-11
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The technical problem to be solved by the present invention is to overcome the defects of poor electrode cycle performance caused by the poor structural stability of existing silicon-based negative electrode materials, and the preparation process is not suitable for industrial production, and to provide a silicon / graphene nanometer coated with carbon Sheet (Si-GNsC) composite negative electrode material and preparation method thereof

Method used

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  • Lithium ion battery anode material and preparation method thereof
  • Lithium ion battery anode material and preparation method thereof
  • Lithium ion battery anode material and preparation method thereof

Examples

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Effect test

Embodiment 1

[0041] The original expanded graphite powder with a purity of 99.9% and a particle size of 100 mesh was heated at a high temperature (1000° C.) for 2 minutes under the protection of argon to obtain a thermally expandable graphite sheet. For comparison of expanded graphite before and after heat treatment, see figure 2 . Depend on figure 2 It can be seen from the comparison photos of the scanning electron microscope that the heat-treated expanded graphite has a loose graphene-like structure, which is suitable as a buffer flexible matrix for silicon-based composite materials.

[0042]2g of the above-mentioned heat-expandable graphite sheets, 2g of nano-silicon powder with a purity of 99.9%, a particle size of ~80 nanometers, and 15g of sucrose with a purity of 99.9% are added to a mixed solution (200ml of ethanol and deionized water volume ratio 1:1 ) and carry out solution ball milling, the ball-to-material ratio is 40:1, the ball mill speed is 1200rpm, and the ball milling t...

Embodiment 2

[0045] The original expanded graphite powder with a purity of 99.9% and a particle size of 100 mesh was heated at a high temperature (1000° C.) for 2 minutes under the protection of argon to obtain a thermally expanded graphite sheet.

[0046] Add 2.5g of the above thermally expandable graphite sheet, 2.5g of silicon powder with a purity of 99.9% and a particle size of ~80nm, and 12.5g of sucrose with a purity of 99.9% to a mixed solution of ethanol and deionized water at a volume ratio of 1:1 (200ml) and carry out solution ball milling, the ball-to-material ratio is 60:1, the ball mill speed is 1200rpm, and the ball milling time is 2 hours; then dry and heat to 600°C for 60 minutes under argon and keep it warm for 2 hours for carbonization to obtain Si- GNsC composite material; the nano-silicon mass accounts for 25% of the total mass of the Si-GNsC composite material; the graphene nanosheet accounts for 25% of the total mass of the Si-GNsC composite material; the amorphous car...

Embodiment 3

[0050] The original expanded graphite powder with a purity of 99.9% and a particle size of 100 mesh was heated at a high temperature (1000° C.) for 3 minutes under the protection of argon to obtain a thermally expanded graphite sheet.

[0051] Add 3 g of the above thermally expandable graphite sheets, 3 g of silicon powder with a purity of 99.9% and a particle size of ~80 nanometers, and 10 g of sucrose with a purity of 99.9% into a mixed solution (200 ml) of ethanol and deionized water at a volume ratio of 1:1 and carry out solution ball milling, the ball-to-material ratio is 60:1, the ball mill speed is 1200rpm, and the ball milling time is 3 hours; then dry and heat to 700°C under argon for 60 minutes and keep it warm for 3 hours for carbonization to obtain Si-GNsC composite material The nano-silicon mass accounts for 30% of the total mass of the Si-GNsC composite material; the graphene nanosheet accounts for 30% of the total mass of the Si-GNsC composite material; the amorp...

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Abstract

The invention discloses a lithium ion battery anode material and a preparation method thereof. The preparation method comprises the following steps: (1), preparing thermal expansion graphite sheets; (2), mixing nano silicon powder, cane sugar and the thermal expansion graphite sheets, adding the obtained mixture to a mixed solution of ethanol and deionized water, stirring and then carrying out solution ball-milling, wherein the ball-milling speed is 800-1600rpm and the ball-milling time is 2-4 hours, so as to obtain an anode material precursor solution; and (3), drying the anode material precursor solution, and carrying out carbonization heat treatment in the atmosphere of a protective gas, so as to obtain the lithium ion battery anode material. The structure characteristics of the lithium ion battery anode material are that nano silicon particles are evenly dispersed on a graphene nanosheet base body and the outermost layer is coated with carbon. The preparation method disclosed by the invention is a method of combining heat treatment with solution ball-milling, and has the characteristics of being simple, efficient and the like; industrialized production is easy to realize; and the lithium ion battery anode material prepared by the method has the advantages of stable structure, good cycle performance and the like.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion batteries, and in particular relates to a carbon-coated silicon / graphene nanosheet composite material for a lithium-ion battery negative electrode and a preparation method thereof. Background technique [0002] Lithium-ion secondary batteries have a series of significant advantages such as high working voltage, large specific capacity, long service life, and no environmental pollution, and have been widely used in various portable electronic devices. The trend of miniaturization, high energy, and portability of electronic appliances, as well as the rapid development of electric vehicles, have higher requirements for the performance of lithium-ion batteries. As a key component of lithium-ion batteries, anode materials have an important impact on the capacity, life, safety, and cost of batteries. Therefore, the research and development of high-performance anode materials is of great significanc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/38H01M4/583H01M10/0525
CPCH01M4/386H01M4/583H01M10/0525H01M2220/30Y02E60/10
Inventor 朱敏孙威胡仁宗曾美琴刘江文
Owner SOUTH CHINA UNIV OF TECH
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