Silicon/expanded graphite/amorphous carbon composite material and preparation method thereof

A technology of expanded graphite and amorphous carbon, which is applied to electrical components, battery electrodes, circuits, etc., can solve problems such as low electrical conductivity, decreased electrode cycle performance, and loss of current collector electrical contact, and achieve high electrical conductivity.

Inactive Publication Date: 2019-04-16
HUNAN SHINZOOM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the silicon negative electrode has a huge volume effect, and the mechanical force generated by the huge volume effect will gradually disengage the electrode active material from the current collector, and the silicon active p

Method used

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  • Silicon/expanded graphite/amorphous carbon composite material and preparation method thereof
  • Silicon/expanded graphite/amorphous carbon composite material and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Step 1. At room temperature, mix ethyl orthosilicate, absolute ethanol and deionized water in a mass ratio of 1:6:4 and stir evenly, slowly add 0.01mol / L oxalic acid solution dropwise to make it hydrolyze, then add dropwise 0.1mol / L of ammonia water was stirred evenly, and left to stand to form an alcohol gel. Put the alcogel seal in a constant temperature water bath at 50°C for aging to obtain a high-strength three-dimensional network structure. Finally, the gel is subjected to supercritical drying to obtain SiO2 airgel block solid.

[0027] Step 2. Mix SiO2 airgel block solid and magnesium powder into two special steel boats at a molar ratio of 2.5:1, then put the steel boats into a container protected by argon and seal them, and then place the sealed Put the container into a tube furnace, raise the temperature to 600°C in an argon atmosphere, keep it warm for 1 h, then cool it down to room temperature, then put it in HCl solution, let it stand at room temperature f...

Embodiment 2

[0031] Step 1. At room temperature, mix and stir ethyl orthosilicate, absolute ethanol and deionized water according to the mass ratio of 1:6:4, slowly add a certain amount of 0.01mol / L oxalic acid solution to hydrolyze it, and then add dropwise 0.1mol / L ammonia water was stirred evenly, and left to stand to form an alcohol gel. It is sealed and aged in a constant temperature water bath at 50°C to obtain a high-strength three-dimensional network structure. Finally, the gel is subjected to supercritical drying to obtain SiO 2 Airgel block solid.

[0032] Step 2, the SiO 2 The airgel block solid and magnesium powder are mixed into two special steel boats at a molar ratio of 5:1, and then the steel boats are put into a container protected by argon and sealed, and then the sealed container is put into a tube type In the furnace, raise the temperature to 900°C in an argon atmosphere, keep it warm for 5 hours, then cool it to room temperature, then put it in HCl solution, let it ...

Embodiment 3

[0036] Step 1. At room temperature, mix and stir ethyl orthosilicate, absolute ethanol and deionized water according to the mass ratio of 1:6:4, slowly add a certain amount of 0.01mol / L oxalic acid solution to hydrolyze it, and then add dropwise 0.1mol / L ammonia water was stirred evenly, and left to stand to form an alcohol gel. It is sealed and aged in a constant temperature water bath at 50°C to obtain a high-strength three-dimensional network structure. Finally, the gel is subjected to supercritical drying to obtain SiO 2 Airgel block solid.

[0037] Step 2, the SiO 2 Airgel block solid and magnesium powder are mixed into two special steel boats at a molar ratio of 3:1, and then the steel boats are put into a container protected by argon and sealed, and then the sealed container is put into a tube In the furnace, raise the temperature to 700°C under an argon atmosphere, keep it warm for 2 hours, then cool it down to room temperature, then place it in HCl solution for 5 h...

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Abstract

The invention provides a preparation method of a silicon/expanded graphite/amorphous carbon composite material. The preparation method comprises the following steps: mixing tetraethoxysilane, absoluteethyl alcohol and deionized water, dropwise adding an oxalic acid solution and ammonia water to form an alcohol gel, aging, carrying out supercritical drying to obtain a SiO2 aerogel blocky solid, mixing the SiO2 aerogel blocky solid with magnesium powder, heating in an argon atmosphere, cooling, then putting into an HCl solution and an HF solution, soaking, cleaning and drying to obtain nano-porous silicon. Then mixing the nano-porous silicon with the expanded graphite in ethanol, stirring, impregnating, filtering, and finally coating in a protective atmosphere to obtain the silicon/expandedgraphite/amorphous carbon composite material. According to the invention, the problem of poor cycle performance caused by a huge volume effect of the silicon negative electrode in the prior art is solved.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a lithium ion battery negative electrode material and a preparation method thereof. Background technique [0002] Silicon-based anode materials have the highest lithium storage capacity and low voltage platform, and are one of the most potential anode materials for next-generation lithium-ion batteries. However, the silicon negative electrode has a huge volume effect, and the mechanical force generated by the huge volume effect will gradually disengage the electrode active material from the current collector, and the silicon active phase itself will also pulverize, thus losing electrical contact with the current collector. , resulting in a rapid decline in electrode cycle performance; and silicon itself is a semiconductor material with low intrinsic conductivity. Contents of the invention [0003] The object of the present invention is to provide a ne...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/38H01M4/62
CPCH01M4/364H01M4/386H01M4/625Y02E60/10
Inventor 彭杨城李能皮涛王志勇邵浩明余梦泽
Owner HUNAN SHINZOOM TECH
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