▎ 摘　　要

NOVELTY - A sandwich-type graphene composite structure consists of a graphene oxide sheet layer (a1), a silicon nanoparticle layer provided on the layer (a1), and a graphene oxide sheet layer (a2) provided on the silicon nanoparticle layer. USE - Sandwich-type graphene composite structure is used for forming cathode of lithium-ion secondary battery. ADVANTAGE - The sandwich-type graphene composite structure has excellent electroconductivity, adhesiveness, and volume expansion relief property with respect to silicone, and suppressed de-intercalation of silicone from the composite structure, and provides battery with excellent durability and high capacity, and is manufactured by economical and environmentally-friendly process. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for manufacture of sandwich-type graphene composite structure, which involves preparing a buffer solution containing dopamine hydrochloride, mixing the silicon nanoparticles with the buffer solution, forming a solution (A), forming polydopamine-coated silicon nanoparticles using the solution (A), mixing a solution (B) containing graphene oxide sheets with the polydopamine-coated silicon nanoparticles, filtering, forming sandwich-type graphene composite structure, and annealing the sandwich-type graphene composite structure for forming carbon-coated silicon nanoparticles and inducing chemical bonding between the carbon-coated silicon nanoparticles and the graphene oxide sheet.