Preparation method of sodium ion battery negative electrode material

The invention provides a preparation method of a sodium ion battery negative electrode material. The preparation method of the sodium-ion battery negative electrode material comprises the following steps: S1, selecting shaddock peel, peanut shell and corn straw according to a mass fraction of 1: 1: (2-5), carrying out KOH activation and carbonization, and carrying out high-temperature cracking to obtain a first carbon source, S2, selecting asphalt, carrying out crosslinking on the asphalt by using a crosslinking agent to change the microstructure of the asphalt, and hindering the growth of graphite microcrystals in the pyrolysis and carbonization process to obtain the sodium-ion battery negative electrode material. S3, the first carbon source and the second carbon source are selected and slowly mixed according to the proportion of 1: (1-2), the mixture is smashed to the diameter of 5-10 nanometers, and the hard carbon precursor is obtained. The hard carbon negative electrode material is obtained through vacuu