Morphological and surface chemical composition disorder induced efficient oxygen evolution and supercapacitor processes into Co3O4 nanostructures

Abstract

In this study, a high-efficiency electrode material based on Co₃O₄ was designed. The electrochemical properties were enhanced when orange peel extract was added during the synthesis of Co₃O₄ using modified hydrothermal process. When electrolyzed with 1 M KOH, 10 mL of orange peel extract mediated Co₃O₄ (sample 2) exhibited 310 mV overpotential at 20 mA/cm² and a Tafel slope of 75 mVdec⁻¹. Tests conducted on sample 2 based on Co₃O₄ over a period of 30 h indicated that it was highly durable at different current densities. Among three electrode cells set up in 3 M KOH electrolytic solution, sample 2 of Co₃O₄ displayed a higher specific capacitance of 2021.88 F/g and a higher energy density of 44.93 Wh/Kg at 1.25 A/g. Using sample 2 of Co₃O₄ as an anode material, the ASC device demonstrated a specific capacitance of 1144.0 F/g and an energy density of 24.95 Wh/Kg at 1.25 A/g. Additionally, the specific capacitance retention percentage during 30,000 GCD cycles at 1.25 A/g and the columbic efficiency were estimated to be about 98.6 %. The improved electrochemical activity of sample 2 of Co₃O₄ may be attributed to reduced optical band gaps, altered particle shapes, reduced particle sizes, and abundant oxygen vacancies. Because of its eco-friendly and low-cost characteristics, orange peel extract could be an excellent alternative option for the design of next generation electrode materials for high performance.