Investigation on microstructure and improved supercapacitive performance of Mn doped CuO thin films prepared by reactive radio frequency magnetron sputtering

Abstract

A reactive radio frequency magnetron sputtering technique was adopted to synthesize un-doped copper oxide and manganese doped copper oxide thin films. XRD analysis confirmed the formation of monoclinic phase of CuO with average crystallite size of about 19 and 15.5 nm for CuO and Mn doped CuO thin films respectively. Field emission scanning electron microcopy investigation indicated that doping of CuO with Mn influences the microstructure of the doped films. The electrochemical measurements using cyclic voltammetry (CV) and galvanostatic charging with potential limited (GCPL) techniques were carried out to study the electrochemical supercapacitive performance of the Mn doped CuO film electrodes. An areal capacitance of the Mn doped CuO film electrode obtained from CV measurements was 81 mF cm−2 measured at 10 mV s−1. The galvanostatic charge–discharge (GCD) measurements exhibited the areal capacitance of 87 mF cm−2 at constant current density of 1 mA cm−2 in 3 M KOH. These GCD profiles were linear and symmetric in nature with the maximum columbic efficiency of about 96%. The electrochemical performance of the Mn doped CuO has indicated that the as-prepared Mn doped CuO film electrodes could be good candidate electrodes for supercapacitor applications.