Growth of vertically-aligned carbon nanotubes on graphite for electric double-layer capacitors

Abstract

Recently, electric double-layer capacitors (EDLCs) have attracted great attention as an energy storage device with high input-output power density. In this study, we synthesized carbon nanotubes (CNTs)/graphite with high surface area as a novel electrode component for EDLC. CNTs were grown on a defective graphite surface by alcohol catalytic chemical vapor deposition for the first time. We found that oxidative plasma treatment time for graphite surface attributes to selective growth of laterally-aligned (LA) or vertically-aligned (VA) CNTs. Electrochemical analysis reveals VACNTs/graphite possesses the highest electrostatic capacity of 1.5 mF cm−2 among pristine graphite, LACNTs/graphite, and VACNTs/graphite. We suggest that increase of specific surface area with CNTs results in the increase of electrostatic capacity for the EDLC electrode. The results indicate that VACNTs/graphite electrodes are expected to improve the performance of EDLCs.