Nano-graphite-doped composite negative electrode material and preparation method thereof

The invention discloses a nano-graphite-doped composite negative electrode material and a preparation method thereof, and belongs to the technical field of battery material preparation. The preparation method comprises the following steps: (1) doping nano-graphite into spartina alterniflora powder, performing primary pyrolysis, and performing secondary pyrolysis after cooling to obtain a mixed carbon material; and (2) sequentially carrying out alkali treatment and acid treatment on the mixed carbon material to obtain the nano-graphite-doped composite negative electrode material. The preparation method is simple and convenient, the spartina alterniflora-sourced hard carbon material (composite negative electrode material) doped with nano-graphite is prepared by adopting the preparation method, the hard carbon material has relatively good first coulombic efficiency, and a battery prepared by taking the hard carbon material as a negative electrode has excellent sodium storage performance. 本发明公开一种掺杂纳米石墨的复合负极材料及其制备