Preparation method of expanded graphite/silicon@carbon negative electrode material for lithium ion batteries

A lithium-ion battery and carbon negative electrode material technology, applied in battery electrodes, secondary batteries, circuits, etc., can solve the problem of insufficient bonding force between silicon nanoparticles and expanded graphite, uneven mixing of silicon nanoparticles expanded graphite and silicon nanoparticles, Eliminate problems such as silicon nanoparticle shedding, achieve excellent cycle stability and rate performance, reduce exposure, and buffer volume changes

Active Publication Date: 2017-01-25
SHANXI INST OF COAL CHEM CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] 1. Simple physical mixing has problems such as agglomeration of silicon nanoparticles and uneven mixing of expanded graphite and silicon nanoparticles
[0007] 2. Although the method of ball milling improves the mixing degree of expanded

Method used

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  • Preparation method of expanded graphite/silicon@carbon negative electrode material for lithium ion batteries
  • Preparation method of expanded graphite/silicon@carbon negative electrode material for lithium ion batteries
  • Preparation method of expanded graphite/silicon@carbon negative electrode material for lithium ion batteries

Examples

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Effect test

Embodiment 1

[0035] A preparation method of expanded graphite / silicon@carbon negative electrode material for lithium ion battery, carried out according to the following method (such as figure 1 shown):

[0036] (1) Add 500mg of expanded graphite to 500ml of nitric acid / sulfuric acid mixed acid solution with a volume ratio of 1 / 1 and soak for 4h, wash to neutral to obtain oxidized expanded graphite, soak the oxidized expanded graphite in 500ml of absolute ethanol 2h to obtain the oxidized expanded graphite ethanol solution mixture.

[0037] (2) The triaminopropyltriethoxysilane coupling agent of 2mg is added in the oxidized expanded graphite ethanol solution mixture obtained in step (1) and stirred for 6h to obtain the alkylated expanded graphite ethanol solution mixture, and then 100mg Silicon nanoparticles are added to the alkylated expanded graphite ethanol solution mixture, stirred and refluxed in a 70° C. water bath for 6 hours to obtain an alkylated expanded graphite / silicon mixed s...

Embodiment 2

[0043] A preparation method of expanded graphite / silicon@carbon negative electrode material for lithium ion battery, carried out as follows:

[0044] (1) Add 200mg of expanded graphite to 100ml of nitric acid / sulfuric acid mixed solution with a volume ratio of 1 / 2 and soak for 8h, wash to neutral to obtain oxidized expanded graphite; soak the oxidized expanded graphite in 40ml of absolute ethanol Soak for 6h to obtain the oxidized expanded graphite ethanol solution mixture.

[0045] (2) Add 5 mg of triaminotriethoxysilane coupling agent to the oxidized expanded graphite ethanol solution mixture obtained in step (1) and stir for 3 hours to obtain the alkylated expanded graphite ethanol solution mixture, and then add 100 mg of silicon nano The particles are added to the alkylated expanded graphite ethanol solution mixture, stirred and refluxed in a water bath at 80° C. for 8 hours, and the alkylated expanded graphite / silicon mixed solution can be obtained. After cooling to room...

Embodiment 3

[0052] A preparation method of expanded graphite / silicon@carbon negative electrode material for lithium ion battery, carried out as follows:

[0053] (1) After adding 100mg of expanded graphite to 20ml of nitric acid / sulfuric acid mixed solution with a volume ratio of 1 / 5 and soaking for 16h, wash to neutrality; after washing to neutrality, oxidized expanded graphite is obtained, and the oxidized expanded graphite is soaked in 8h in 10ml absolute ethanol obtains the oxidized expanded graphite ethanol solution mixture;

[0054] (2) Add 20 mg of triaminotriethoxysilane coupling agent to the oxidized expanded graphite ethanol solution mixture obtained in step (1) and stir for 9 hours to obtain the alkylated expanded graphite ethanol solution mixture, and then add 50 mg of silicon nano The particles are added to the mixture of alkylated expanded graphite ethanol solution, stirred and refluxed in a water bath at 100°C for 4 hours to obtain an alkylated expanded graphite / silicon mix...

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Abstract

The invention relates to a preparation method of an expanded graphite/silicon@carbon negative electrode material for lithium ion batteries. The method comprises the following steps: introducing oxygen-containing functional groups to the lamellae of expanded graphite subjected to acid treatment to obtain oxidized expanded graphite, soaking the oxidized expanded graphite in an ethanol solution to obtain an oxidized expanded graphite ethanol solution mixture containing rich hydroxyls on the surface, stirring the mixture with a silane coupling agent to obtain an alkylated expanded graphite ethanol solution mixture, adding silicon nanoparticles to obtain an alkylated expanded graphite/silicon ethanol mixed solution, adding the mixed solution into an amorphous carbon precursor, reacting, collecting the precipitate, drying, carbonizing, and soaking in a hydrofluoric acid solution to obtain the expanded graphite/silicon@carbon negative electrode material for lithium ion batteries. The method has the advantages of favorable loop stability and favorable magnification property.

Description

technical field [0001] The invention relates to an expanded graphite / silicon@carbon negative electrode material for a lithium ion battery and a preparation method thereof. [0002] technical background [0003] Lithium-ion batteries have the advantages of high theoretical specific capacity, long cycle life, and high safety, and are widely used in portable electronic devices, such as mobile phones, computers, and digital cameras. Commercial lithium-ion battery anode material graphite has low lithium storage capacity (theoretical specific capacity is 372mAh / g) and poor rate performance, which cannot meet the energy demand of large-scale energy storage devices. Therefore, it is particularly important to develop anode materials for lithium-ion batteries with high capacity and long cycle life. Silicon has attracted the attention of many researchers because of its high theoretical specific capacity (4200mAh / g), low charge and discharge voltage, and abundant reserves. However, the...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/0525
CPCH01M4/362H01M4/386H01M4/625H01M4/628H01M10/0525Y02E60/10
Inventor 宋燕李肖田晓冬杨桃刘占军
Owner SHANXI INST OF COAL CHEM CHINESE ACAD OF SCI
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