▎ 摘　　要

In this paper, in situ synthesis of 3D-graphene/MnO2 foam composite using the combination of chemical vapor deposition and hydrothermal method was reported for producing highly efficient graphene/metal oxide-based hybrid supercapacitors. The in situ conformal growth of 3D-graphene/MnO2 composite exhibited high crystallinity and low contact resistance, thereby improving the charge transport efficiency of the electrolyte. Compared with the previously described MnO2-based counterparts, the porous structure of the 3D conductive graphene foam permitted electrolyte ions to rapidly move around the surface of MnO2. In the supercapacitor, the 3D-graphene/MnO2 composite electrode in the absence of carbon black showed high specific capacitance (333.4 F g(-1) at 0.2A g(-1)) with excellent cycling stability. This technical approach for fabrication of 3D-graphene/MnO2 composite provides a promising means in the production of energy storage electrode materials for designing high performance supercapacitor devices.