▎ 摘　　要

NOVELTY - Preparing porous silicon composite material comprises (a) vacuumizing the porous silicon, mixing the porous silicon with dopamine solution under high pressure, and maintaining the pressure, (b) drying the pressure-retained porous silicon, vacuum-treating the porous silicon, then mixing it with graphene oxide solution and reducing agent under high pressure for maintaining the pressure, and (c) drying the porous silicon after maintaining the pressure and heat-treating. USE - The porous silicon composite material is useful in preparing cathode of lithium ion power battery (claimed). ADVANTAGE - The method: uses polydopamine composite thin layer, which can chemically react with the oxygen-containing functional groups on the graphene oxide surface; reduces graphene by contacting with a reducing agent; reduces the contact area of porous silicon and electrolyte; and improves the first efficiency of porous silicon. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) porous silicon composite material prepared by the above method; (2) use of porous silicon composite material in preparing cathode of lithium ion power battery; (3) cathode of lithium ion power battery comprising porous silicon composite material; and (4) lithium ion power battery comprising the cathode of the lithium ion power battery.