Synthesis and study of rare earth(Dy3+) doped CoCr2O4 ceramics for supercapacitor applications

Abstract

Rare earth doped Cobalt Chromates are exhibits a significant interest among other materials for supercapacitors Applications. In the present work we reported Dysprosium(Dy3+) doped Cobalt Chromate(CoCr2O4) for possible application in supercapacitors. Samples were prepared by solution combustion method with the general formula CoCr2-xDyxO4 (where x = 0, 0.01, 0.03, and 0.05) using glucose and urea as fuels. As prepared samples were characterized by using “X-ray diffractometer”(XRD), “Transmission electron microscopy”(TEM), and “field emission scanning electron microscopy(FESEM) techniques to study the analytical and morphological structure of the CoCr2-xDyxO4. For the first time, the electrochemical fabrication of CoCr2-xDyxO4 were reported. Using “cyclic voltammetry”(CV), “galvanostatic charge–discharge’(GCD), electrochemical impedance spectroscopy (EIS), and cyclic stability testing, the electrochemical capabilities of CoCr2-xDyxO4 were explored in great detail. The behavior of capacitance was evaluated utilizing CV at a variety of scan speeds, GCD at a selection of constant current densities, and EIS at a selection of frequencies. CV and GCD data for tested electrodes showed their capacitive behavior. The calculated capacitance was 0.29–0.38 F cm−2. It is found increasing with Dy3+ concentration. Based on CV testing results at a scan rate of 1 mV s−1. At a current density of 3 mA cm2, the obtained capacitance was 0.21, 0.22 and 0.23 F cm−2 respectively. The analysis of the compared Nyquist plots of complex impedance revealed that the actual part of the impedance dropped as the Dy3+ content increased. This pointed to an increase in conductivity, which was advantageous for the storage of charge, as also supported by density of states calculations, which demonstrated the remarkable distribution of density of states across the fermi level after Dy3+ doping in CoCr2O4, indicating improved electronic features of CoCr2-xDyxO4.