Preparation method of porous silicon carbon negative electrode material

The invention aims to provide a preparation method of a porous silicon carbon negative electrode material, and belongs to the technical field of lithium ion battery negative electrode materials, the preparation method comprises the following steps: crushing and grinding asphalt, dissolving in tetrahydrofuran, adding a prepared nanometer silicon ethanol solution while stirring, drying the solvent by distillation, and carrying out high-temperature treatment under the protection of inert gas to obtain the porous silicon carbon negative electrode material. Derived carbon generated by asphalt at a high temperature can coat silicon, and then asphalt silicon is etched by an alkali solution, so that a porous structure is formed. The adopted raw material is nanometer silicon, the volume effect of silicon in the charging and discharging process can be relieved, and the silicon powder and the asphalt can be better and uniformly mixed by using tetrahydrofuran as a solvent, so that the uniform coating of the asphalt pyrol