▎ 摘　　要

NOVELTY - Graphene coated silica nano particles comprises reduced graphene/carbon shell covered outer layer, silicon nanoparticles located in the reduced graphene/carbon shell, and cavity layer between the reduced graphene/carbon shell and silicon nanoparticle core. USE - Used as graphene coated silica nano particles. ADVANTAGE - The nano particles: compared with the existing technology, the silicon particles surface oxide layer thickness is easy to control; contains the silicon powder on the surface oxide is easy to be dispersed in the solvent, and the hydroxy groups of particle surface makes easy to combine with the modifier; increases the electrical contact between the particles when the graphene particles coated on the surface; is good composite material internal electronic transfer reduces the impedance, modifier generated by high temperature cracking carbon and graphene together form a shell with a certain intensity and good forming stable solid electrolyte interfaces. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing graphene coated silica nano particles comprising (i) using surface oxidation, adding the silicon powder in high temperature furnace, under the condition of an oxygen containing atmosphere, keeping the temperature of 300-1000 degrees C for 0.5-20 hours to obtain the oxygen content of 8-57 wt.% silicon powder, (ii) placing into the dispersing agent and ultrasonically dispersing to obtain silicon powder solution, adding 0.1-10 mg/ml silicon powder, the dispersant is water or mixed solution of absolute ethyl alcohol or both at any volume concentration in the dispersant, (iii) adding modifier in the silicon powder solution, stirring at constant temperature for 1-24 hours to obtain the mixed solution at the constant temperature is 20-80 degrees C, the quality of the modifying agent is 25-100 wt.% silicon, (iv) filtering, washing off un-modified modifier, dispersing the filtrating thing into water to prepare concentration of 0.5-10 mg/ml dispersion, (v) taking the 20-100 wt.% silicon powder, graphene oxide solution is dripping iin the dispersion, stirring for 1.0-24 hours, centrifuging and collecting the precipitate product and vacuum drying, where the graphene oxide solution is 0.5-2.0 mg/ml, (vi) placing the dried product into a high-temperature furnace, raising the temperature to 700-900 degrees C under an inert atmosphere, keeping the temperature for 1-3 hours to obtain the graphene coated silicon composite material, and (vii) obtaining graphene coated composite material, adding 5 wt.% diluted hydrofluoric acid solution, fully washing and drying after reaction, and obtaining with new structure of graphene coated silicon nano particle composite material, quantity of the hydrofluoric acid in the diluted hydrofluoric acid solution is 20 to %-143 of silicon powder.