Method for preparing lithium battery silicon carbon anode material by utilizing magnesiothermic reduction

Abstract

The invention relates to a method for preparing a lithium battery silicon carbon anode material by utilizing magnesiothermic reduction. The method comprises the following steps: preparing a mixed solution of sodium silicate, glucose and sodium chloride; heating and drying to obtain a brown caramel-shaped precursor; heating the precursor to 650 DEG C for calcining in the atmosphere of Ar to obtain a sodium silicate / carbon precursor; adding HCl into the sodium silicate / carbon precursor to prepare a mixed solution by utilizing a principle of preparing weak acid by strong acid; subsequently, drying the mixed solution in a drying oven at 170 DEG C; washing a sample with water to obtain a silicon dioxide / porous carbon composite material; uniformly mixing the silicon dioxide / porous carbon composite material, magnesium powder and sodium chloride; calcining at 700 DEG C, and performing acid treatment, water washing and drying to obtain a silicon carbon composite material. According to the method, a carbon / silicon dioxide composite material can be directly reduced and the silicon carbon composite material is successfully prepared.

Description

technical field [0001] The invention relates to a technology for preparing a silicon-carbon negative electrode material of a lithium-ion battery by a magnesia thermal reduction method. Background technique [0002] The negative electrode material is the main lithium storage body of the lithium-ion battery, and it realizes the intercalation and extraction of lithium ions during the charging and discharging process. In recent years, due to the shortcomings of traditional carbon materials such as low specific capacity, low initial charge and discharge efficiency, and co-intercalation of organic solvents, people have begun to develop other non-carbon materials with high specific capacity. Silicon materials are rich in natural resources, cheap, and more importantly, silicon has a high theoretical capacity (up to 4200mAh / g), and it is safer than graphite materials when used as the negative electrode of lithium-ion batteries, so it has been studied. However, serious volume changes...

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Problems solved by technology

However, these methods have high production costs and limited output, and the chemical vapor deposition method uses silane as a silicon source. Silane is active in nature and is extremely easy to be oxidized. When it comes into contact with air, it will spontaneously ignite, and there is a danger of explosion.

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