Forest-like carbon foam templated rGO/CNTs/MnO2 electrode for high-performance supercapacitor

Inspired by the unique structure of the forest in nature, a hierarchical carbon foam templated rGO/CNTs/MnO2 composite has been successfully fabricated by electrophoresis deposition, chemical vapor deposition and electrochemical deposition, in aims of combining the high mechanical stability of porous 3D carbon foam framework, the large specific surface area of 2D graphene and the fast charge transfer property of 1D CNTs, as well as the large pseudo-capacitance of MnO2 nanoparticles. The electrochemical performances were carefully investigated in a three-electrode system and compared with CF-rGO and CF-rGO/CNTs prepared by the same method. The results reveal that, CF-rGO/CNTs/MnO2 exhibits the highest specific capacitance (332.5 F/g at 0.5 A/g) among the three electrodes, with an excellent capacitance retention as high as 89.2% after running for 10,000 cycles at 5 A/g. Meanwhile, an asymmetric supercapacitor was assembled using CF-rGO/CNTs/MnO2 as positive electrode while active carbon as negative electrode, which exhibits an extended operating potential window ranging from 0 to 1.8 V and a superior energy density of 41.6 Wh/kg at corresponding power density of 513.7 W/kg. These extraordinary electrochemical properties give the as-prepared composite great potential to replace conventional electrode materials as high energy storage supercapacitors.