Silicon-carbon alloy cathode material used in lithium ion battery, and preparation method thereof

Abstract

The invention discloses a silicon-carbon alloy cathode material used in a lithium ion battery, and a preparation method thereof. The invention aims at improving the cycling performance of the silicon-carbon alloy cathode material. According to the silicon-carbon alloy cathode material, silicon powder particles with particle sizes of 20-250nm are adopted as substrates; carbon nano-tubes and amorphous carbon are coated on the surfaces of the substrates; the thicknesses of the carbon nano-tubes and amorphous carbon are 100-300nm; the carbon nano-tubes and amorphous carbon are short-strip-shaped, block-shaped, or layered hollow-structured cracked carbon. The preparation method provided by the invention comprises steps of: slurry preparing, drying and powder preparing, calcining, and chemical vapor depositing. Compared to prior arts, the silicon-carbon alloy cathode material is advantaged in high specific capacity, good cycling performance, a capacity greater than 1000mAh / g, and a capacity maintenance rate above 90% with 20 times of circulation. The preparation method provided by the invention is advantaged in simple technology and low raw material cost. The material and the method provided by the invention are suitable for various high-capacity lithium ion battery cathode materials.

Description

technical field [0001] The invention relates to a battery negative electrode material and a preparation method thereof, in particular to a lithium ion battery negative electrode material and a preparation method thereof. Background technique [0002] Lithium-ion batteries have the advantages of high voltage, high energy density, no memory effect, long life, green and pollution-free, and low self-discharge. They have become the preferred power supply equipment for various portable electronic products and are inseparable from people's daily life. With the increasingly severe global environmental problems, the concept of "low carbon" is becoming more and more popular. The many advantages of lithium-ion batteries make lithium-ion batteries expected to replace petroleum products as ideal power sources for portable electric tools and electric vehicles. Play a more important role in human production and life. [0003] The negative electrode materials of lithium-ion batteries in th...

AI Technical Summary

Problems solved by technology

However, there is a large volume change of lithium ions in the process of intercalation and deintercalation of the negative electrode prepared by silicon materials. Such a large volume change can cause the prepared electrode to pulverize and fall off, resulting in the separation of the electrode active material and the current collector. , thus seriously affecting the cycle performance of the battery

The volume effect of silicon materials has become a huge obstacle to the industrialization of silicon anode materials

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