▎ 摘　　要

NOVELTY - Preparing porous silicon/carbon nanotube composite material involves grinding metal magnesium and silicon dioxide in a high-speed grinding machine, transferring the ground metal magnesium and silicon dioxide into a tube furnace, heating the ground metal magnesium and silicon dioxide to 400-600℃ in an argon atmosphere for thermal reduction, adding the ground metal magnesium and silicon dioxide into a nitric acid solution for soaking for 24 hours, removing the metal magnesium through acid washing, and drying to obtain porous silicon A, where the mass ratio of the components is metal magnesium to silicon dioxide = (2-4): 1, preparing a nickel nitrate solution with the mass concentration of 1-5%, adding the porous silicon A, stirring uniformly. USE - Method for preparing porous silicon/carbon nanotube composite material. ADVANTAGE - In the method, the carbon nano tube growing on the surface of the porous silicon by utilizing the catalytic action of the nickel per se vertically grows on the surface of the porous silicon, so that the intercalation and deintercalation channel of lithium ions in the charging and discharging process is improved, the quick charging performance of the lithium ion is improved, and meanwhile, the cycle performance of the lithium ion is improved by utilizing the characteristics of good liquid absorption performance and low expansion of the porous silicon material. DETAILED DESCRIPTION - Preparing porous silicon/carbon nanotube composite material involves grinding metal magnesium and silicon dioxide in a high-speed grinding machine, transferring the ground metal magnesium and silicon dioxide into a tube furnace, heating the ground metal magnesium and silicon dioxide to 400-600℃ in an argon atmosphere for thermal reduction, adding the ground metal magnesium and silicon dioxide into a nitric acid solution for soaking for 24 hours, removing the metal magnesium through acid washing, and drying to obtain porous silicon A, where the mass ratio of the components is metal magnesium to silicon dioxide = (2-4): 1, preparing a nickel nitrate solution with the mass concentration of 1-5%, adding the porous silicon A, stirring uniformly, adding a graphene solution and urea, transferring into a high-pressure reaction kettle, reacting at 150-200℃ for 1-12 hours through a hydrothermal reaction, filtering and drying to obtain a nickel-doped porous silicon composite material B, wherein the mass ratio of the components is nickel nitrate to the porous silicon A to graphene to urea = (1-5) = (0.5-2): 0.1-0.5), and transferring the nickel-doped porous silicon composite material B into a tubular furnace, firstly introducing inert gas to remove air in the tube, then introducing carbon source gas, heating to 600-1000℃, preserving the temperature for 1-6 h, then stopping introducing the carbon source gas, introducing the inert gas, naturally cooling to room temperature, and then carrying out acid washing and drying to obtain the porous silicon/carbon nanotube composite material.