▎ 摘　　要

NOVELTY - Sandwich rod-type silicon carbon cathode material comprises carbon nanotube layer, silicon layer, polydopamine carbon layer, and graphene layer from inside to outside, the shape of the silicon carbon cathode material is similar to a sandwich rod. The preparation of the sandwich rod-type silicon carbon cathode material comprises (1) dispersing carbon nanotubes in mixed solution containing deionized water, ethanol and aqueous ammonia, adding tetraethyl orthosilicate, stirring at room temperature for 30-60 minutes, washing with deionized water and ethanol for many times to obtain carbon nanotube/silicon dioxide complex; and (2) depositing layer of silicon on surface of above-mentioned carbon nanotube/silicon dioxide complex by chemical vapor deposition, etching with 3-10 wt.% hydrofluoric acid for 2-5 hours, removing the silicon dioxide layer, washing with deionized water and ethanol for many times to obtain carbon nanotube/silicon complex. USE - Used as sandwich rod-type silicon carbon cathode material. ADVANTAGE - The cathode material: can actively inhibits the excessive growth of the SEI film, improves the Coulomb efficiency, significantly improves the conductivity of the material, improves the volume expansion of the silicon cathode material, prevents the silicon layer from being pulverized when exposed to the electrolyte, and improves the cycle performance and energy density of the lithium ion battery.