This invention discloses a
graphene-coated
silicon nanocomposite material, its preparation method, and its application, belonging to the field of battery materials technology. The preparation method of this
composite material includes: firstly, removing the
oxide layer on the surface of the
silicon nanocomposite and performing
plasma activation to obtain
silicon nanocomposite with active sites and functional groups on the surface; dispersing it in a
carbon source precursor solution, mixing it evenly, and then centrifuging and
drying it at low temperature to obtain a silicon-coated precursor; under
inert gas protection, carbonizing the silicon-coated precursor at 500-700℃ and simultaneously introducing it into a catalyst precursor, then introducing a carrier gas containing
hydrogen and carbon, and heat-treating it at 800-950℃; finally,
acid washing,
water washing, and
drying to obtain the target material. This invention achieves low-temperature controllable growth of
graphene by optimizing process parameters. In the prepared core-shell
composite material, 1-30 few-layer
graphene shells are tightly bonded to the silicon nanocomposite core. When used as a negative
electrode active material for
lithium-
ion batteries, it exhibits high specific capacity, excellent cycle stability, and rate performance. The process is easily scalable and has promising application prospects.