Eco-friendly hydrothermal synthesis of Co3O4-based NiO–Fe2O3 binary and ternary nanocomposites for electrochemical energy storage applications

The increasing global demand for advanced energy storage technologies necessitates the development of high-performance materials. In this study, Co₃O₄-based NiO-Fe₂O₃ binary and ternary nanocomposites were synthesized via a green hydrothermal method using banana peel extract as a sustainable reducing agent. The Phase analysis, microstructural, elemental composition, electrochemical, and magnetic properties of synthesized materials were analyzed using X-ray diffractions (XRD), scanning electron microscope (SEM), energy dispersive x-rays (EDX), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV), and vibrating sample magnetometry (VSM) technique. XRD analysis confirmed the coexistence of binary (NiO-Co₃O₄) and ternary Fe₂O₃-NiO-Co₃O₄ phases in the nanocomposite. The surface morphology analysis showed the presence of spherical and round-like shape. Electrochemical analysis revealed a high specific capacity of 2692 mAh g⁻¹ for the Fe₂O₃-NiO-Co₃O₄ nanocomposite, significantly surpassing the binary compound. The corresponding energy densities were 391.2, 363.2, 328.2 J/mA.cm⁻², with Tafel slopes of 112, 129, and 118 mV/dec, respectively. The VSM results indicated retentivity values of 1.49, 2.53, and 1.03 emu/g for NiO/Co₃O₄, Fe₂O₃/Co₃O₄, and Fe₂O₃/NiO/Co₃O₄ nanocomposite. The energy dispersive x-rays (EDX) spectroscopy confirmed the presence of Co, O, Fe, and Ni elements. These findings highlight the potential of Co₃O₄-based NiO/Fe₂O₃ nanocomposites as promising candidates for high performance energy and data storage applications.