Vertically aligned carbon nanotubes grown on carbon fabric with high rate capability for super-capacitors

Vertically aligned carbon nanotubes (VACNTs) were directly grown on carbon fabric (CF) using the controllable injection chemical vapor deposition without the pretreatment of the surface of CF. Electrochemical characterization indicated that VACNT/CF electrodes achieved a relative high specific capacitance of 75 F g−1 at a current density of 1 A g−1 due to large specific surface area and low contact resistance. The specific capacitance still remained 63 F g−1 at a high current density of 100 A g−1 with the retention of 84%, which far exceeded other carbonaceous materials. This excellent rate capability of VACNT/CF electrodes was attributed to large mesopore size, three-dimensional hierarchical architecture and aligned pathway, facilitating the diffusion of electrolyte ions. In addition, the area-normalized capacitance of VACNT/CF electrodes was improved remarkably by prolonging the growth time of CNT.