▎ 摘　　要

NOVELTY - Preparing silicone based negative active material involves preparing a milling slurry comprising 15 wt.% silicon powder having an average particle diameter of 1 mu m, 1.5 wt.% of graphene powder, and a solvent, introducing the slurry into a milling chamber containing zirconia balls, and the nano graphite layer having a size in the range of 60-130 nm and the nano graphite layer in contact with the nano silicon for forming a nano silicon composite having an average particle diameter of 90 nm, including a silicon composite layer forming an interface of the graphite layer, agglomerating the nanosilicon composite by a spray drying method to form agglomerated powder having an average particle diameter of 25 mu m, adding a pitch powder containing 25% mesophase pitch to the agglomerated powder and mixing with a tubular mixer to form a mixture partially comprising an amorphous carbon layer, filling and molding the mixture into a molding machine to obtain a compression molded body. USE - Method for preparing silicone based negative active material for lithium ion secondary battery (claimed) for portable devices, electric bicycles, and power tools. ADVANTAGE - The method enables to prepare negative electrode active material having excellent adhesion of the carbon coating on the surface of the agglomerated powder, high energy density, high energy density and long service life. DETAILED DESCRIPTION - Preparing silicone based negative active material involves preparing a milling slurry comprising 15 wt.% silicon powder having an average particle diameter of 1 mu m, 1.5 wt.% of graphene powder, and a solvent, introducing the slurry into a milling chamber containing zirconia balls, and the nano graphite layer having a size in the range of 60-130 nm and the nano graphite layer in contact with the nano silicon for forming a nano silicon composite having an average particle diameter of 90 nm, including a silicon composite layer forming an interface of the graphite layer, agglomerating the nanosilicon composite by a spray drying method to form agglomerated powder having an average particle diameter of 25 mu m, adding a pitch powder containing 25% mesophase pitch to the agglomerated powder and mixing with a tubular mixer to form a mixture partially comprising an amorphous carbon layer, filling and molding the mixture into a molding machine to obtain a compression molded body, heat-treating the compression molded body at 430 degrees C for 6 hours in a nitrogen atmosphere, pulverizing and classifying the heat-treated compression molded body to obtain particles having an average particle diameter of 10 mu m.