Metal Oxide Heterostructures as Multifunctional Electrode Materials for Battery-Type Supercapacitor and Oxygen Evolution Reaction

Abstract

This study demonstrates the successful synthesis of pristine Bi2O3, Co3O4, and Bi2O3/Co3O4 heterostructure for their investigation in electrochemical energy storage and electrocatalytic performance. Among all the fabricated electrodes for battery-type supercapacitor, Bi2O3/Co3O4 heterostructure exhibits maximum specific capacitance of 2998 F g⁻¹ at 1 A g⁻¹ which is due to the synergistic interaction between pristine Bi2O3 and Co3O4 nanoparticles. Furthermore, the Bi2O3/Co3O4 heterostructure employed asymmetric supercapacitor device with a specific capacitance of 237 F g-1 at 2 A g-1. The device shown remarkable energy density of 32.97 Wh kg⁻¹ at a power density of 0.333 kW kg⁻¹. Additionally, Bi2O3/Co3O4 catalyst displayed an excellent oxygen evolution reaction result in both alkaline and neutral media with very low overpotentials of 464 mV and 153 mV at current densities of 50 mA cm⁻² and 10 mA cm⁻², respectively. While the values of Tafel slope, electrochemical surface area, and charge transfer resistance confirmed the fast electrode kinetics and high density of active sites. The fabricated electrode depicted long-term stability when tested for 24 hours under chronoamperometry. These findings indicate that the Bi2O3/Co3O4 heterostructure is an appealing electrode material for energy storage and generation applications.