Iron oxide induced effects on the electrochemical stability and specific capacity of hafnium oxide electrode for supercapacitor applications

Abstract

In the context of discovery of electroactive materials for energy storage applications with high energy storage, remarkable charge-discharge capabilities and outstanding electro-conductivity, herein, we have designed (hafnium oxide)x–(iron oxide)1−x based electrodes (where x = 1, 0.75, 0.50, 0.25, 0) in various stoichiometric ratios towards achieving a high-performance supercapacitor. The fabricated electrode successfully integrates the nanostructure design with synergistic effects, contributed by hafnium oxide and iron oxide nanoparticles. The morphological and structural aspects of this electrode have been systematically probed, followed by agile probing of electrochemical traits. Scientific techniques like cyclic voltammetry, galvanostatic charging/discharging and electrochemical impedance spectroscopy are the tools employed for the investigation of superior charge storage capacity. The nanocomposited electrode has achieved a superior specific capacitance of 1866 F g−1 at a current density of 1 A g−1 in 2 M NaOH electrolyte. Moreover, this electrode material has achieved an outstanding specific energy density of 64.79 Wh-kg−1 and specific power density of 249.8 W-kg−1 with a capacity retention of 79 % over 5000 cycles. This work significantly enhances the fundamental understanding of using high-k dielectrics in the field of energy storage devices.