Fusion with greener magnetite – a d7 oxide as an agent for lower energy demand

Abstract

Energy storage devices will play an important role globally in green energy in the future, to meet the demand for lower energy use. Supercapacitors currently have significant applications in the field of energy. We chose Catharanthus roseus as a capping agent for a Co₃O₄@Fe₃O₄ nanocomposite (NC), using a simple hand grinding mechanochemical method, to examine the high specific capacitance that occurs in the prepared NC. XRD, FTIR, SEM, TEM, XPS, and electrochemical studies, including cyclic voltammetry (CV), galvanostatic charge discharge (GCD), and electrochemical impedance spectroscopy (EIS), were used to characterise the material in terms of structure, chemical composition, surface morphology, and elemental composition. The reported material exhibits a high specific capacitance of 2669 F g⁻¹ at 1 mV s⁻¹ in a 2 M KOH electrolyte solution, and the energy density and power density for the Co₃O₄ NC are 333.62 Wh kg⁻¹ and 900 W kg⁻¹, respectively, with a cycling stability of 36.39% for a 7 A g⁻¹ capacitive current for over 4400 cycles. Similarly, an assessment of the performance of an asymmetric two electrode device results in a value of 157.52 F g⁻¹ for the current 3 A g⁻¹, and it is stable for about 1000 cycles with a retention of 76.33%. This work suggests that Co₃O₄@Fe₃O₄ might serve as a viable material for energy storage.