▎ 摘　　要

Mn3O4 nanoparticles were in-situ synthesized in the 3D framework of reduced graphene oxide (RGO) by a facile one-step hydrothermal method. In the reduced graphene-Mn3O4 (RGM) composite, the RGO network not only serves as a mechanical support to construct a self-supported and binder-free electrode, but also offers 3D continuous conductive network for effective electron transfer. The Mn3O4 nanoparticles anchored uniformly across the RGO framework, which provided high capacity and prevented the restacking of the RGO thin sheets. Based on the unique composite structures, strong synergistic effect was achieved between Mn3O4 and RGO, resulting in superior specific capacity, enhanced rate capability, stable cycling performance and nearly 100% Coulombic efficiency in the RGM2 composites. With an optimal Mn3O4 composition of 44% by weight (similarly hereinafter), the composite exhibits high specific capacities of 696-795 mAh g(1) based on the overall weight of the electrode in 60 cycles at 200 mA g(-1), with a large coulombic efficiency of around 98%. Even at a high current density of 10,000 mA g(-1), the composite can still deliver a capacity of 383 mAh g(-1), demonstrating its excellent rate performance. The outstanding performances of the composites are attributed to the synergistic effect of both components and the hierarchical structure of the composite.