▎ 摘　　要

Graphene composite materials have attracted significant attention for green energy storage systems due to their excellent electrochemical properties. We report a low-cost and environmentally friendly approach for synthesis of 3D multilayer graphene nanostructures (3DMGS) via catalytic graphitization and chemical oxidation-thermal reduction using biomass-based activated carbon (AC) as a precursor. The combination of microwave catalytic graphitization and chemical oxidation results in an active material with a unique physical and chemical structure. 3DMGS possesses a high specific surface area (503 m(2) g(-1)) and an interconnected hierarchical porous structure with many defects and edges, which provide sufficient lithium-ion diffusion sites and facilitate fast ion transportation. When used as anode material for Li-ion batteries, 3DMGS exhibit outstanding rate capability and cycling stability (260 mAhg(-1) at 5000 mAg(-1) after 1100 cycles with charge retention of 114.47%.) and ultrahigh specific capacity (1513 mAhg(-1) at 100 mAg(-1)). (C) 2021 Elsevier Ltd. All rights reserved.