▎ 摘　　要

The synthesis of graphene-based composite materials for Li-ion batteries using an in situ growing technique is first proposed in this work. Graphene frame supported silicon@graphitic carbon granules were obtained through a one-step solid-state reaction using iron phthalocyanine (FePc) and silicon nanoparticles (SiNPs) as the precursors. Nitrogen-doped graphene was grown in situ around the SiNPs by pyrolyzing and re-carbonizing FePc, and a cross-linked graphene frame network was gradually formed. Simultaneously, SiNPs were wrapped by a thin graphitic carbon layer, and the strong interconnections between the graphene, graphitic carbon and SiNPs led to a spontaneous self-assembly process, resulting in the formation of mm scale granules with available nanoporosities and irregular channels. The self-assembled granules with excellent electrical conductivity can effectively accommodate the volume change of the SiNPs during the repeating discharge-charge processes, therefore high capacity, long cycle life, high Coulombic efficiency and superb rate capability have been realized. The synthesis strategy is facile, safe, low-cost and can be easily industrialized, providing a broadly applicable route for the in situ synthesis of more functional graphene-based composite materials.