Electrochemical Double-Layer Capacitance of MoS[sub 2] Nanowall Films

Abstract

Edge-oriented films synthesized by single source precursor chemical vapor deposition exhibit a high density of nanowalls, which can potentially exhibit excellent electrochemical charge storage properties. The electrochemical double-layer capacitance of layered, nanowalled film has been investigated in this work using electrochemical impedance spectroscopy. We show that edge-oriented thin films can behave as a supercapacitor at alternating current frequencies up to . The supercapacitor performance is comparable to that of carbon nanotube array electrodes. In addition to double-layer capacitance, diffusion of the ions into the films at slow scan rates gives rise to faradaic capacitance, which enhances the capacitance significantly. The real and imaginary part of the capacitance of the films was analyzed as a function of frequency, in order to obtain information on the relaxation time constant and frequency dependence of the supercapacitor properties.