Highly energetic flexible all-solid-state asymmetric supercapacitor with Fe2O3 and CuO thin films

Abstract

In the present investigation, the applicability of Fe₂O₃ and CuO thin films as anode and cathode electrodes respectively in supercapacitors has been systematically studied. Fe₂O₃ and CuO thin films are synthesized by simple and cost effective chemical methods and further more all-solid-state symmetric (Fe₂O₃/Fe₂O₃, CuO/CuO) and asymmetric (CuO//Fe₂O₃) supercapacitor devices are fabricated. The electrochemical properties (cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), electrochemical impedance spectroscopy (ESR), etc.) of these devices are studied using two electrodes system. The asymmetric supercapacitor shows improved performance with maximum operating potential window of 2.0 V and specific capacitance of 79 F g⁻¹ at 2 mA cm⁻² current density. The maximum energy density and power density of 23 W h kg⁻¹ and 19 kW kg⁻¹ are obtained for asymmetric supercapacitor. In addition, the asymmetric supercapacitor demonstrates the excellent flexibility with capability retention of 89% over bending at an angle of 180°.