Composite negative electrode material, preparation method thereof and lithium ion battery

The invention provides a composite negative electrode material, a preparation method thereof and a lithium ion battery. The preparation method comprises the following steps: S1, carrying out coating treatment on a graphite material by adopting a liquid-phase coating agent to obtain a coated product; the liquid-phase coating agent is a mixture of asphalt and a liquid-state single-molecule carbon-containing organic matter or the liquid-state single-molecule carbon-containing organic matter; and S2, carrying out carbonization treatment on the coated product in an inert atmosphere to obtain the composite negative electrode material. Compared with a method of directly using a graphite material as a negative electrode material of a lithium ion battery, the composite negative electrode material prepared by the method can modify surface defects such as holes and dislocation of the graphite material, and can increase lithium intercalation sites on the surface of the material, so that the lithium intercalation capabili