Exposed Edge Planes of Cup-Stacked Carbon Nanotubes for an Electrochemical Capacitor

Abstract

The end sites of graphitic planes and their catalytic, chemical, physical, and electrochemical roles have been a longstanding issue in the surface chemistry of carbon science. In this study, complete exposure of the active edge sites on the outer surface of catalytically grown cup-stacked carbon nanotubes is accomplished using a conventional exfoliation method, and its intrinsic contribution to the improvement of the electrochemical behavior in an electrochemical capacitor is demonstrated. The significant enhancement in the capacitance of the nanotubes after exfoliation, occurring without a distinctive change in pore structure, was confirmed with the exposure of the electrochemically active edge sites thus being able to accumulate more charge. Such active sites make nanotubes useful in the fabrication of high-performance electrochemical capacitors, catalysts, supporting materials for catalysts, and photocurrent generators in photochemical cells