Lithium ion battery silicon-based composite anode material and preparation method thereof

The invention discloses a preparation method of a lithium ion battery silicon-based composite anode material, which comprises the following steps: (1) mixing silicon powder, graphite, a dispersant and water to obtain slurry, wherein the average particle size D50 of the silicon powder and graphite is 380-500 nm; (2) performing spray granulation to obtain particles; (3) mixing a sodium carboxymethylcellulose aqueous solution with a mass volume concentration of 1.5-4.7 g/L with the particles, wherein the using amount of sodium carboxymethylcellulose is 1-3 wt% of the total amount of the silicon powder and the graphite, stirring, performing centrifugation separation, drying, sieving by using a sieve of more than 400 meshes to obtain the undersize. The invention also discloses a lithium ion battery silicon-based composite anode material prepared by the method, which has a high specific capacity, and good cycle performance.