▎ 摘　　要

NOVELTY - A mixed solution containing graphene oxide, polystyrene microspheres, silica powder and polyimide acid is spray-dried under stirring at 130-180 degrees C to obtain fluffy powder. The fluffy powder is placed in tube furnace, heated from room temperature to 180-240 degrees C and heating rate of 3-5 degrees C/minute under inert gas protection for 50-80 minutes, further heated from 180-240 degrees C to 750-850 degrees C and heating rate of 3-5 degrees C/minute for 120-150 minutes, cooled and naturally cooled to room temperature, to obtain graphene/silicon porous microsphere electrode with hierarchical structure. USE - Preparation of graphene/silicon porous microsphere electrode used for battery. ADVANTAGE - The method enables preparation of three-dimensional graphene/silicon porous microsphere electrode having excellent magnification stability. The battery comprising three-dimensional graphene/silicon porous microsphere electrode has current density of 3 A/g and capacity of more than 370 mAh/g. DETAILED DESCRIPTION - A graphene oxide is prepared by adding natural graphite and potassium permanganate to 98 %mass sulfuric acid, placing mixture in ice bath and stirring at 300-400 rpm for 1-2 hours to obtain mixture (a). The mixture (a) is heated at 35 degrees C for 1 hour. Deionized water is added to mixture (a). The mixture is heated at 90-95 degrees C and further heated at 90-95 degrees C for 30-35 minutes, to obtain mixture (b). The mixture (b) is naturally cooled to room temperature. Hydrogen peroxide solution with fraction of 35 %mass is added to mixture (b), stirred at room temperature and 100-300 rpm and reacted for 10 minutes, to obtain aqueous solution of graphene oxide. The aqueous solution of graphene oxide is centrifuged at 3000-3500 rpm. Supernatant is taken and centrifuged at 8000-8500 rpm. Sediment material is centrifugally separated and processed at 60-80 degrees C for 1-3 hours, to obtain graphene oxide. A mixed solution containing graphene oxide, polystyrene microspheres, silica powder and polyimide acid is prepared by dissolving graphene to water, to obtain enriched graphene solution with concentration of 5-15 g/L, dissolving polystyrene microspheres in water, to obtain polystyrene microsphere solution with fraction of 8-15 %mass, adding silicon powder and 50% polyamic acid aqueous solution to distilled water, stirring mixture at 200-500 rpm for 30 minutes to obtain silica powder solution, adding silica powder solution to graphene solution, stirring at 500-1000 rpm, reacting for 1-2 hours and ultrasonically dispersing for 1-2 hours, to obtain dark mixed solution, adding 8-15 %mass polystyrene microspheres solution to dark mixed solution, stirring mixture at 500-1000 rpm for 1-2 hours and ultrasonically dispersing for 1-2 hours. The mixed solution containing graphene oxide, polystyrene microspheres, silica powder and polyimide acid is spray-dried under stirring at 130-180 degrees C to obtain fluffy powder. The fluffy powder is placed in tube furnace, heated from room temperature to 180-240 degrees C and heating rate of 3-5 degrees C/minute under inert gas protection for 50-80 minutes, further heated from 180-240 degrees C to 750-850 degrees C and heating rate of 3-5 degrees C/minute for 120-150 minutes, cooled from 750-850 degrees C to 180-240 degrees C and cooling rate of 5-8 degrees C/minute and naturally cooled to room temperature, to obtain graphene/silicon porous microsphere electrode with hierarchical structure. The mass ratio of natural graphite and potassium permanganate is 1:5. The mass ratio of natural graphite and 98 %mass sulfuric acid is 1 g:60-100 mL. The volume ratio of mixture (a) and deionized water is 1:1. The mass ratio of natural graphite and hydrogen peroxide solution is 1 g:(5-6 mL). The volume ratio of silica powder and distilled water is (100-300 g):20 mL. The volume ratio of polyimide acid aqueous solution and distilled water is (0.5-2):20. The volume ratio of silica powder solution and graphene oxide solution is (15-25):30. The volume ratio of polystyrene microsphere solution and dark mixed solution is 50:(30-60).