Silicon-carbon composite cathode material of lithium ion battery and preparation thereof

Abstract

The invention provides a silicon-carbon composite cathode material for preparing a lithium-ion battery at the room temperature and a preparation method thereof. The composite cathode material is a material with a nuclear shell structure and comprises the following proportional elements: 0.01-10% of simple substance silicon and 90-99.9% of carbon. With regard to the preparation method, silicon powder and graphite are mixed for ball grinding and then added with bitumen or polymer cladding material for ball grinding again, after the treatment of carbonization, the mixture is crushed and sieved to obtain the material containing 0.01-10wt% of silicon and 10-99.9% of carbon. The capacity of the material is more than 350mAh / g, the cycle efficiency of the material is larger than 90% for the first time, and keeps larger than 80% after 200 cycles, and the material has good charging and discharging property.

Description

technical field

[0001] The invention relates to a battery negative electrode material and a preparation method thereof, in particular to a silicon-carbon composite negative electrode material of a lithium ion battery and a preparation method thereof. Background technique

[0002] Since Japan's Sony Corporation took the lead in developing and commercializing lithium-ion batteries in 1990, lithium-ion batteries have developed rapidly. Today lithium-ion batteries have been widely used in various fields of civil and military use.

[0003] At present, the negative electrode material of commercial lithium-ion batteries uses graphite-based carbon materials, but its theoretical specific capacity is only 372mAh / g, which limits the further improvement of the specific energy of lithium-ion batteries and cannot meet the growing demand for high-energy portable mobile power supplies. , and carbon materials have problems such as low charge-discharge capacity, poor high-rate charge-dischar...

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