One-step fabrication and capacitive behavior of electrochemical double layer capacitor electrodes using vertically-oriented graphene directly grown on metal

We report on a one-step binder-free fabrication method for electrochemical double layer (EDL) capacitor electrodes consisting of vertically-oriented graphene uniformly grown on a metallic current collector. The double-layer capacitive behavior of the resulting electrode is studied in both aqueous and organic electrolytes. Compared with conventional graphene-based EDL capacitor electrode fabrication methods, this method offers the following advantages: (a) no need to use a binder, (b) open channels for better ion access, and (c) exposed edge planes for improved material wettability. These unique features lead to excellent capacitive behavior in organic electrolytes, including a specific capacitance slightly higher than that in aqueous electrolytes at the same potential scan rate and a high knee frequency (similar to 3174 Hz in the current work). (C) 2012 Elsevier Ltd. All rights reserved.