Lithium ion battery surface modified graphite negative electrode material and preparation method thereof

The invention discloses a lithium ion battery surface modified graphite negative electrode material and a preparation method thereof. A graphite material is prepared through the following steps of heating a graphite material to a certain temperature in a manner of isolating the graphite material from air, conducting heat preservation for a period of time, then adding the heated graphite into deionized water to be rapidly cooled, and filtering and drying the cooled graphite material to obtain a surface modified material. The modified graphite material obtained through adopting the method has good surface properties, oxygen-containing groups on the surface are reduced, micropore channels are increased, and the rate charge-discharge performance and the first effect of the material are improved under the condition that the charge capacity of the material is not changed. Since molecules of the graphite material in a high-temperature state are in an active state, surface stress generated by rapid cooling enables an