A silicon-carbon composite electrode material with core-shell structure and preparation method thereof

A core-shell structure and electrode material technology, applied in structural parts, battery electrodes, circuits, etc., can solve the problems of low specific capacity, large volume expansion, poor cycle performance, etc., to prevent mutual agglomeration, improve capacity, and good conductivity. Effect

Active Publication Date: 2016-10-05
BEIJING UNIV OF CHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] One of the objects of the present invention is to provide a lithium-ion battery negative electrode material and a preparation method thereof, to overcome the problems of poor cycle performance and low specific capacity caused by large volume expansion of lithium-ion battery negative electrode materials

Method used

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  • A silicon-carbon composite electrode material with core-shell structure and preparation method thereof
  • A silicon-carbon composite electrode material with core-shell structure and preparation method thereof
  • A silicon-carbon composite electrode material with core-shell structure and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0032] Disperse 400 mg of negative electrode active material silicon monoxide (purity mass fraction greater than or equal to 99.99%, particle diameter is 100-300 nanometers) after ball mill ball milling in 320 milliliters of ethanol and 80 milliliters of deionized water, ultrasonically make it Disperse evenly, then add 4 ml of concentrated ammonia water (mass fraction 28%), the pH value is between 7-9. Subsequently, under vigorous stirring (stirring rate 600-800rpm), 1.6 ml of ethyl orthosilicate was added into the dispersion, and the stirring state was kept for 12 hours to obtain a silica-coated product. 200 mg of the obtained coated silicon dioxide sample was placed in a tube furnace reactor, and nitrogen gas was introduced at a flow rate of 100 ml / min. Raise the temperature to 620°C, replace the acetylene / nitrogen mixed gas (the volume fraction of acetylene content is 5%) with chemical vapor deposition gas, the flow rate is 100 ml / min, keep the temperature at 620°C for 20 m...

Embodiment 2

[0034]Disperse 400 mg of negative electrode active material silicon monoxide (purity mass fraction greater than or equal to 99.99%, particle diameter is 100-300 nanometers) after ball mill ball milling in 320 milliliters of ethanol and 80 milliliters of deionized water, and make it Disperse evenly, then add 4 milliliters of concentrated ammonia water (mass fraction 28%). Subsequently, under vigorous stirring (stirring speed 600-800 rpm), 1.6 ml of ethyl orthosilicate was added into the dispersion, and the stirring state was maintained for 12 hours to obtain a silica-coated product. 200 mg of the obtained coated silicon dioxide sample was placed in a tube furnace reactor, and nitrogen gas was introduced at a flow rate of 100 ml / min. The temperature was raised to 620°C, and the mixed gas of acetylene / nitrogen (the content of acetylene was 5% by volume fraction) was replaced with chemical vapor deposition gas, the flow rate was 100 ml / min, and the acetylene carbon was deposited a...

Embodiment 3

[0036] Disperse 400 mg of negative electrode active material silicon monoxide (purity mass fraction greater than or equal to 99.99%, particle diameter is 100-300 nanometers) after ball mill ball milling in 320 milliliters of ethanol and 80 milliliters of deionized water, and make it Disperse evenly, then add 4 milliliters of concentrated ammonia water (mass fraction 28%). Subsequently, under vigorous stirring (stirring speed 600-800 rpm), 1.6 ml of ethyl orthosilicate was added into the dispersion, and the stirring state was maintained for 12 hours to obtain a silica-coated product. 200 mg of the obtained coated silicon dioxide sample was placed in a tube furnace reactor, and nitrogen gas was introduced at a flow rate of 100 ml / min. Raise the temperature to 620° C., replace the acetylene / nitrogen mixed gas (the volume fraction of acetylene content is 5%) with chemical vapor deposition gas, the flow rate is 100 ml / min, and keep at 620° C. for 1 hour to deposit acetylene carbon....

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Abstract

The invention relates to a silicon-carbon composite electrode material of a core-shell structure and a preparation method thereof, and belongs to the technical field of lithium ion batteries. The material consists of a carbon hollow spherical shell and a negative electrode active material-silicon monoxide coating the carbon hollow spherical shell internally so as to form a core-shell structure; the mass percentage of silicon monoxide is 50%-60%, and the mass percentage of the carbon hollow spherical shell is 40%-50%. The preparation method comprises the following steps: carrying out high-energy ball milling on silicon monoxide, then dispersing into ethyl alcohol and deionized water, dispersing uniformly via an ultrasonic instrument, then adding strong ammonia water and tetraethoxysilane, and stirring uniformly so as to obtain silicon dioxide coated silicon monoxide powder; depositing acetylene carbon at a high temperature by adopting a chemical gas phase deposition method under the protection of protective gases; and processing a product after acetylene carbon deposition by hydrofluoric acid, thereby obtaining the lithium ion battery negative electrode material. The material has a core-shell structure, reserves an expansion space for silicon in a lithium embedment and removing process, and is conductive to improving the electrochemical cyclic performance.

Description

technical field [0001] The invention relates to a silicon-carbon composite electrode material with a core-shell structure and a preparation method thereof, belonging to the technical field of lithium ion batteries. Background technique [0002] Lithium-ion battery is a high-efficiency, new type of green chemical power supply. Its own characteristics of high working voltage, low self-discharge, high specific energy, no pollution, high safety, and no memory effect make it more and more popular among people. favor. Lithium-ion batteries have been widely used in portable electronic devices, and have quite broad application prospects in electric vehicles (EVS) and hybrid electric vehicles (HEVs). [0003] Traditional lithium-ion battery anode materials are carbon materials, generally graphite materials. Although these materials have good cycle performance, and the volume change is small in the process of lithium intercalation and delithiation. However, when it is charged for t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/36
CPCH01M4/48H01M4/625Y02E60/10
Inventor 朱红王挺
Owner BEIJING UNIV OF CHEM TECH
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