Silicon negative electrode material and preparation method thereof

The invention relates to a silicon negative electrode material and a preparation method thereof. The preparation method comprises the following steps: mixing nano silicon particles, hexadecyl trimethyl ammonium bromide and ethanol, stirring, and carrying out pretreatment; dispersing the pretreated nano silicon particles in water, then adding ascorbic acid, hexadecyl trimethyl ammonium bromide, urotropin and zinc nitrate, and carrying out a first heating reaction to obtain a precursor; mixing the precursor with an aqueous solution of N, N-dimethylformamide, dimethylimidazole and a cobalt salt,and carrying out a second heating reaction to obtain a ZIF-67 coated silicon material; and enabling the ZIF67 coated silicon material to be subjected to sintering. According to the preparation method,the MOF derived porous carbon is used for coating the silicon nanoparticles, so that the problems of structural pulverization and the like caused by 3-4 times of volume expansion and shrinkage of silicon in the lithium interc