Surface Modified Activated Carbons Prepared from Orange Peel Waste as Potential Electrodes for Li-Ion Capacitors

Abstract

In this work, orange peel waste was used as the precursor for activated carbon-based electrodes for Li-Ion Capacitors. Initially, activated carbons were prepared by chemical activation process using ZnCl2. The surface of the activated carbon was then modified with the oxidative chemical agents such as H2SO4, HNO3, H2O2 and KOH solutions. The morphology, surface chemical composition, and surface area of the surface modified carbon materials were studied by scanning electron microscope, X-ray photoelectron spectroscopy, and Brunauer– Emmett–Teller measurement, respectively. Electrochemical characteristics of the as-prepared sample were investigated by cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and the electrochemical impedance spectroscopy (EIS) measurements. Experimental results showed that the surface modification had a very significant effect on the improvement of electrochemical characteristics of activated carbon as electrodes in super capacitors. The good electrochemical performance of the activated carbon was attributed to well-developed micropores, high surface area, the presence of oxygen functional groups, and larger pore volume. The results indicate that orange peel waste can potentially be applied as a raw material for the production of low cost activated carbon electrode materials for Li-Ion Capacitors.