Electrochemistry of the Basal Plane versus Edge Plane of Graphite Revisited

The electrochemical activity of the basal plane and edge plane of graphite has long been a subject of an extensive debate. While significant advances have been made, several gaps still exist in our understanding of this issue, namely, the relative differences in the electrochemical activity of the perfect basal plane and perfect edge plane and the dependence of measurable electrochemical quantities on the edge/defect density of the basal plane. In this work, we employ a microdroplet electrochemical cell technique and atomic force microscopy to measure localized electrochemical properties of the graphitic surface with known edge coverage. The electron transfer rate, capacitance, and density of electronic states of the perfect basal plane and perfect edge plane are estimated, and a qualitative model is proposed for the dependence of the electrochemical quantities on the defect density of the basal plane.