High-performance electrochemical capacitors using electrodeposited MnO2 on carbon nanotube array grown on carbon fabric

Abstract

Carbon fabric (CF)-carbon nanotube array (CNTA)/MnO2 composites with a 3D porous structure are prepared by the electrochemical deposition for high-performance electrochemical capacitors. MnO2 nanoflowers assembled with the petal-like nanosheets uniformly attach on the surface of CNTs. Electrochemical characterization indicates that the maximum specific capacitance of CF-CNTA/MnO2 reach to 740Fg−1 (based on MnO2 alone) with a mass loading of 0.34mgcm−2 at the scan rate of 2mVs−1, which is much better than that of MnO2 electrodeposited on the stainless steel and the CF. And the specific capacitance can remain 326Fg−1 even with a mass loading of 4.09mgcm−2. While a reasonable area-normalized capacitance of 2081mFcm−2 is achieved with this high mass loading at 0.1mVs−1. The rate capability measurement shows the CF-CNTA/MnO2 achieved a high retention of 70% with a scan rate range of 2–200mVs−1, which outperform others 3D porous MnO2-based electrodes reported previously. These excellent electrochemical performances are attributed to large surface area, 3D porous structure and aligned ion diffusion channels of the CF-CNTA/MnO2 composite electrodes.