Electrochemical studies on chromium doped SrTiO3 for supercapacitor applications

Abstract

Perovskite oxides have garnered significant attention as potential active materials for supercapacitor applications. Recently, metal-doped perovskite oxides have gained prominence due to their potential to provide a synergistic blend of electrical conductivity, substantial electrochemical active surface area, and robust electrochemical activity. In this study, we systematically investigate the electrochemical properties of strontium titanate oxide (SrTiO_3, STO) and chromium-doped strontium titanate oxide (Cr-STO), synthesized via the solid-state reaction method. Various material characterization techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS), are employed to examine the crystal structure, morphology, and chemical composition of these samples. Notably, Cr-STO demonstrates an approximately twentyfold increase in electrochemical surface area compared to pristine STO, resulting in enhanced anion storage capabilities when employed in alkaline 3 M KOH aqueous electrolytes. Detailed electrochemical kinetic studies reveal an augmented pseudocapacitive behavior in Cr-STO, with a more pronounced diffusive nature compared to pristine STO. Furthermore, symmetric supercapacitors fabricated with Cr-STO electrodes exhibit excellent electrochemical performance, maintaining over 93 % of their initial capacity after 10,000 charge-discharge cycles at a current density of 1 A g⁻¹. These findings highlight the significant potential of chromium-doped strontium titanate oxide as a valuable contribution to the ongoing pursuit of novel material for supercapacitors.