A low expansion, long life silicon-carbon composite material and preparation method thereof

Abstract

The present invention relates to the technical field of lithium-ion battery materials, and discloses a low-expansion, long-life silicon-carbon composite material and a preparation method thereof. Porous carbon and porous metal oxide are mixed evenly to obtain a carbon-based composite precursor, and then nano-silicon is deposited in the precursor by a silane cracking method, and finally nitrogen-doped amorphous carbon is deposited thereon by a plasma method to obtain a silicon-carbon composite material. The present invention utilizes a silane cracking method to uniformly deposit nano-silicon in porous carbon and porous metal to reduce expansion, and deposits a carbon source with a low cracking temperature on the outer layer to avoid the enlargement of the silicon grains in the inner core, reduce expansion, and coat the outer layer to isolate the contact between nano-silicon and the electrolyte, thereby improving the circulation and storage performance. The silicon-carbon composite material prepared by the present invention is applied to lithium-ion batteries, and has the characteristics of low expansion, good circulation, and high energy density.

Images