Silicon-carbon composite negative electrode material and preparation method thereof

The invention discloses a silicon-carbon composite negative electrode material and a preparation method thereof, the silicon-carbon composite negative electrode material contains composite particles, the composite particles take agglomerated carbon nanotubes as a skeleton, gaps of the carbon nanotube skeleton are filled with silicon-carbon fillers, the carbon nanotube skeleton is coated with a carbon covering layer, and the carbon covering layer is coated with a silicon-carbon filler. The preparation method comprises the following steps: shaping a carbon nano tube to form a compact pellet-shaped structure, obtaining a carbon nano tube aggregate as a framework for subsequent treatment, then carrying out asphalt coating to reduce the specific surface area of the carbon nano tube aggregate, then carrying out silicon-carbon vapor deposition, and finally carrying out carbon coating outside the framework. Based on the carbon-silicon negative electrode material provided by the invention, the initial coulombic effici