Dysprosium doped calcium tungstate as an efficient electrode material for the electrochemical energy storage devices

Tungstate-based nanostructures improve electrochemical performance and offer many advantages due to their charge transport capabilities, excellent corrosion resistance, and superior optical and electrical characteristics. The main purpose of this study is to synthesize the calcium tungstate and dysprosium (Dy) doped calcium tungstate nanomaterials by using the hydrothermal method and investigate the effect of Dy doping on the electrochemical properties of calcium tungstate nanomaterials. The Dy doping changes the structural properties of materials such as a decrease in crystallite size, change in lattice parameters, and volume of the unit cell. The band gap of CaWO4 reduces from 3.32 eV to 3.06 eV with increasing Dy concentration. SEM images reveal the spherical shape of the CaWO4 and Dy (0.8%) doped CaWO4 nanomaterials. The electrochemical properties show that Dy doping enhances the performance of CaWO4 nanomaterials as a supercapacitor. The specific capacity increases to 624 C/g with 0.8% Dy doping in CaWO4 as compared to 115 C/g of undoped CaWO4 at a sweep rate of 5 mV/s. The theoretical evaluation shows that the diffusion-controlled mechanism dominates with the increasing sweep rate which presents the potential of Dy (0.8%) doped CaWO4 for supercapattery-based hybrid devices.