Silicon-carbon composite material and preparation method thereof

The invention discloses a silicon-carbon composite material and a preparation method thereof, the silicon-carbon composite material is of a core-shell structure, and the silicon-carbon composite material sequentially comprises a carbon material core, a nanometer silicon coating layer, a high-first-effect silica layer and a carbon layer from inside to outside. The silicon-carbon-graphite composite material with a novel structure is prepared in a three-step vapor deposition mode, the silicon-carbon-graphite composite material sequentially comprises a carbon material inner core, a nanometer silicon coating layer, a high-first-effect silica layer and a carbon layer from inside to outside, the advantages of nanometer silicon and silica are combined, the nanometer silicon adopts a silicon source deposition mode, the dispersion is uniform, the particle size is controllable, and the carbon-carbon-graphite composite material is prepared. The silicon oxide is subjected to raw material end pre-lithiation to improve the