Method for preparing core-shell type silicon/carbon composite material through in-situ carbon coating and application of core-shell type silicon/carbon composite material

A carbon composite material, core-shell type technology, applied in the direction of electrical components, electrochemical generators, battery electrodes, etc., can solve the problems of difficult to achieve the level of practical application, high production cost, low output, etc., to achieve mass production, ratio High capacity, simple and controllable process

Active Publication Date: 2019-11-29
宇恒电池股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The specific capacity and cycle performance of nano-silicon / carbon composites have been improved, but the preparation cost of this method is high and the output is low, which is difficult to reach the level of practical application

Method used

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  • Method for preparing core-shell type silicon/carbon composite material through in-situ carbon coating and application of core-shell type silicon/carbon composite material
  • Method for preparing core-shell type silicon/carbon composite material through in-situ carbon coating and application of core-shell type silicon/carbon composite material
  • Method for preparing core-shell type silicon/carbon composite material through in-situ carbon coating and application of core-shell type silicon/carbon composite material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Grind 5g of micron silicon powder and 0.5g of lithium carbonate evenly, put them into a closed heating tube to evacuate, then heat up to 650°C at a heating rate of 5°C / min for reaction, and the holding time is 10h; after the reaction, cool to room temperature. The product was successively soaked in 1M dilute hydrochloric acid for 3 hours, soaked in 10% hydrofluoric acid for half an hour, washed with deionized water and alcohol three times. Then, it was filtered by suction and dried in vacuum at 80° C. to obtain a core-shell silicon / carbon composite material. figure 1 It is the XRD diffraction pattern of the composite material, compared with the standard card, it is elemental silicon. figure 2 It is the SEM picture of the composite material. It can be seen that the product is a silicon / carbon composite material with a core-shell structure with a layer of carbon coating on the surface of silicon powder.

[0026] The core-shell silicon / carbon composite material prepared...

Embodiment 2

[0029] Grind 8g of nano-silicon powder and 1g of lithium carbonate evenly, put them into a closed heating tube to evacuate, then heat to 500°C at a heating rate of 5°C / min for reaction, and the holding time is 10h; after the reaction, cool to room temperature . The product was successively soaked in 1M dilute hydrochloric acid for 3 hours, soaked in 10% hydrofluoric acid for half an hour, washed with deionized water and alcohol three times. Then, it is filtered by suction and dried under vacuum at 80° C. to obtain a core-shell silicon / carbon composite material.

Embodiment 3

[0031] Grind 10g of silicon / aluminum alloy powder and 2g of lithium carbonate evenly, put them into a closed heating tube to evacuate, and then heat up to 800°C at a heating rate of 5°C / min for reaction, and the holding time is 10h; after the reaction, cool to room temperature. The product was successively soaked in 1M dilute hydrochloric acid for 3 hours, soaked in 10% hydrofluoric acid for half an hour, washed with deionized water and alcohol three times. Then, it was filtered by suction and dried in vacuum at 80° C. to obtain a core-shell silicon / carbon composite material.

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PUM

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Abstract

The invention discloses a novel method for preparing a core-shell type silicon/carbon composite material through in-situ carbon coating. The method comprises the steps of: performing ball milling on lithium carbonate and silicon powder in a certain ratio for 3-96 hours, and transferring the mixture into a closed reactor; heating the reactor at a temperature rise rate of 0.2-20 DEG C/min to a temperature of 400-800 DEG C, performing heat preservation for 0.5-20 h; and after the reaction is finished, performing cooling to a room temperature, taking out a product in the reactor, sequentially soaking in 1M diluted hydrochloric acid for 3h, soaking in 10% hydrofluoric acid for half an hour and washing with deionized water and alcohol for three times; and performing suction filtration, and performing vacuum drying at a temperature of 80 DEG C to obtain a silicon/carbon composite material. The method provided by the invention is simple in process, low in reaction temperature and strong in operability; according to the novel method for preparing the core-shell type silicon/carbon composite material, the morphology of the obtained product is of a core-shell type structure, the product has the excellent electrochemical performance as a lithium ion battery anode material, and the discharge capacity is close to 1300mAh/g after 50 times of circulation under the current density of 1 Ag-1.

Description

technical field [0001] The invention relates to a new method for obtaining a carbon-coated core-shell type silicon / carbon composite material by direct reaction of lithium carbonate and silicon and its application as a lithium ion battery negative electrode material. Background technique [0002] With the rapid development of society and economy, various electronic devices, storage devices, especially new energy electric vehicles, need to increase the energy density of lithium-ion batteries. At present, graphite is the most widely used anode material for lithium-ion batteries, but its theoretical specific capacity is only 372mAh / g, which cannot meet the application requirements of high-energy-density lithium-ion batteries. Silicon has a high theoretical specific capacity (up to 4200mAh / g) and a low lithium intercalation and extraction potential, and is a high specific capacity negative electrode material that can replace graphite negative electrodes. However, compared with g...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/58H01M10/0525
CPCH01M4/366H01M4/386H01M4/5825H01M10/0525Y02E60/10
Inventor 黄辉余佳阁梁初张文魁夏阳卞飞翔张俊甘永平贺馨平
Owner 宇恒电池股份有限公司
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