Vertical Graphene@Carbon Fiber Covered with MnO2 Flower-Like Nanostructures via Electrodeposition for High-Performance Supercapacitors

The research systematically investigated the synthesis process and electrochemical performances of willowy integrated MnO2/vertical graphene@carbon fiber (MnO2/GCF) hybrids. With the highly willowy carbon fiber as skeleton, graphene and ultrathin MnO2 nanosheets were grown via plasma enhanced chemical vapor deposition and cyclic voltammetric electrodeposition, in sequence respectively. The triaxial (3D) MnO2/GCF networks demonstrated highly multihole structure. Ascribed to the good performance, MnO2/GCF nanomaterials can be manufactured into supercapacitor electrodes straightway and doesn't use binder as well as conductive agents. In addition, the electrochemical performance of the MnO2 nanoflakes increased not only because of the fast ion diffusion among the triaxial porous vertical graphene@carbon fiber framework but also excellent contact of its' interfaces and outstanding synergistic effect between each other. In this paper, the capacitance performance of MnO2/GCF composite samples with different electrodeposition time of MnO2 nanoflakes was investigated. The results showed that the MnO2/GCF composite with electrodeposition time of 64 min (MnO2/GCF-64) had the highest specific capacitance of 565.23 F g(-1) when the current density was 1 A g(-1) and excellent cycling stability (82% specific capacitance retention after 2000 cycles). The willowy vertical graphene@carbon fiber substrate covered with flower-like MnO2 nanosheets can serve as high performance supercapacitor, which enjoys a promising application prospect.