Surface effect of electrodes revealed by operando surface science methodology

Super-dense anions together with cations intercalation into the surface region of graphite electrode has been visualized by applying operando surface science methodology over an Al/HOPG planar model device. The observed unusual electrochemical behavior in surface region can be described as the intercalation pseudocapacitor in contrast with the battery process in the bulk. Guided by this distinct surface effect, the capacity can be doubled by using surface-dominant nano-thick graphite electrode.