Silicon-carbon composite material and preparation method thereof, and application of silicon-carbon composite material

A technology of silicon-carbon composite materials and silicon-based materials, applied in nanotechnology, electrical components, electrochemical generators, etc. for materials and surface science, can solve problems such as poor reversible specific capacity, reduce consumption and increase reversibility Effect of specific capacity and high reversible specific capacity

Inactive Publication Date: 2019-09-03
XIAMEN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to overcome the poor reversible specific capacity of silicon-based materials prepared by diatomite only through magnesothermic reduction in the prior art, and to provide a silicon-based material prepared ...

Method used

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  • Silicon-carbon composite material and preparation method thereof, and application of silicon-carbon composite material
  • Silicon-carbon composite material and preparation method thereof, and application of silicon-carbon composite material
  • Silicon-carbon composite material and preparation method thereof, and application of silicon-carbon composite material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] (1) Add 0.1625g metal magnesium powder, 0.1993g diatomite powder and 2.2025g sodium chloride powder into the ball mill and ball mill at a speed of 180r / min for 2.5h, then put the resulting mixture into a tube furnace, and feed Argon gas was used as a protective atmosphere, and the temperature was raised to 650°C at a rate of 2°C / min for 3 hours, and then cooled to room temperature naturally, and the product was placed in 65ml of 1mol / L hydrochloric acid solution and washed for 5.5h, then centrifuged, and circulated according to this method Wash and centrifuge 3 times, and finally put the product into a vacuum oven to dry for 12 hours to obtain a silicon-based material.

[0042] (2) Get 120 mg of the silicon-based material obtained in step (1) and disperse it into a mixed solution consisting of 320 ml of absolute ethanol and 80 ml of deionized water, perform ultrasonic treatment, then add 4 ml of concentrated ammonia water (mass fraction: 28%, the same below), then under...

Embodiment 2

[0047] (1) Put 0.2400g metal magnesium powder, 0.3041g diatomite powder and 3.0451g sodium chloride powder into the ball mill and ball mill at a speed of 120r / min for 10h, then put the resulting mixture into a tube furnace and pass through argon Gas was used as a protective atmosphere, and the temperature was raised to 700°C at a rate of 5°C / min for 3 hours, and then cooled to room temperature naturally, and the product was placed in 65ml of 1mol / L hydrochloric acid solution for stirring and washing for 6 hours, then centrifuged, and the centrifuged cycle was washed according to this method 3 times, and finally put the product into a vacuum drying oven to dry for 12 hours to obtain a silicon-based material.

[0048] (2) Take 150 mg of the silicon-based material obtained in step (1) and disperse it into a mixed solution composed of 320 ml of absolute ethanol and 80 ml of deionized water, and perform ultrasonic treatment, then add 4 ml of concentrated ammonia water to the resulti...

Embodiment 3

[0053] (1) Add 0.3120g metal magnesium powder, 0.4010g diatomite powder and 4.1430g sodium chloride powder into the ball mill and ball mill at a speed of 150r / min for 6h, then put the resulting mixture into a tube furnace and pass through argon Air was used as a protective atmosphere, and the temperature was raised to 650°C at a rate of 5°C / min for 6 hours, and then cooled to room temperature naturally, and the product was placed in 65ml of 3mol / L hydrochloric acid solution for stirring and washing for 8 hours, and then centrifuged. 3 times, and finally put the product into a vacuum drying oven to dry for 12 hours to obtain a silicon-based material.

[0054] (2) Disperse 150 mg of the silicon-based material obtained in step (1) into a mixed solution consisting of 200 ml of absolute ethanol and 50 ml of deionized water, perform ultrasonic treatment, then add 2.5 ml of concentrated ammonia water to the resulting dispersion, and then Under vigorous stirring, 1 ml of ethyl orthosi...

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Abstract

The invention belongs to the field of lithium ion battery silicon-carbon anode materials, and discloses a silicon-carbon composite material and a preparation method thereof, and application of a silicon-carbon composite material. The preparation method of the silicon-carbon composite material comprises the following steps of: (1) uniformly mixing metal magnesium powder, diatomite powder and a moderator, then performing redox reaction, cooling, washing and drying to obtain a silicon-based material; (2) dispersing a silicon-based material in a solvent, adding an alkaline catalyst and tetraethoxysilane, performing stirring for reaction, washing and drying to obtain a silicon dioxide-coated silicon-based material; (3) dispersing the silicon dioxide coated silicon-based material in water, adding cetyl trimethyl ammonium bromide and an alkaline catalyst for uniform stirring, adding the mixture into resorcinol and formaldehyde, performing stirring for reaction, washing, drying, and calciningat a high temperature to obtain the carbon and silicon dioxide coated silicon-based material; and (4) etching the carbon and silicon dioxide coated silicon-based material. The silicon-carbon compositematerial provided by the invention has a good electrochemical performance and high reversible specific capacity.

Description

technical field [0001] The invention belongs to the field of silicon-carbon negative electrode materials for lithium-ion batteries, and in particular relates to a silicon-carbon composite material and a preparation method and application thereof. Background technique [0002] In the past five years, electric vehicles have developed rapidly, and as the main source of power for electric vehicles, lithium-ion batteries have also attracted worldwide attention, but lithium-ion batteries still face problems such as low energy density. It is an effective method to find anode materials with higher specific capacity, and silicon not only has abundant reserves, but also has a specific capacity as high as 4200mAh / g and a reasonable discharge voltage (Li / Li + ≈0.5V), is a very potential negative electrode material. However, the volume expansion / shrinkage of silicon anodes will exceed 300% during the lithium intercalation / delithiation process, which will not only cause the active partic...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/0525B82Y30/00
CPCB82Y30/00H01M4/366H01M4/386H01M4/625H01M10/0525Y02E60/10
Inventor 罗学涛叶雄彪甘传海徐颖黄柳青
Owner XIAMEN UNIV
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