A surface oxygen-modified CoAlFe LDH@Fe3O4-based high-performance supercapacitor: structural modification for improved electrochemical stability

Abstract

Supercapacitors are a family of energy storage devices that have attracted significant attention because of their high power density, quick charge and discharge times, and extended cycle life. For the development of high-performance supercapacitors, electrodes with high specific capacitance values along with good structural stability are essential. In this context, we report the synthesis of a surface oxygen-modified CoAlFe LDH@Fe₃O₄ heterostructure using a simple hydrothermal route followed by post modification using hydrogen peroxide. High crystallinity and phase purity were confirmed by structural studies employing X-ray diffraction (XRD), and functional groups essential to electrochemical performance were revealed by Fourier-transform infrared spectroscopy (FTIR). XRD and FTIR results confirmed the formation of the heterostructure with the presence of magnetic Fe₃O₄. In addition, the surface oxygen coordination was found to be significantly improved. Excellent retention, low internal resistance, and better capacitive behavior were demonstrated by electrochemical studies. For the electrochemical evaluation of the heterostructure, a 1 M KOH electrolyte was used. A remarkable specific capacitance value of 1709.6 F g⁻¹ at a current density of 1 A g⁻¹ was achieved. In addition, the heterostructure exhibited excellent durability with 89.39% capacity retention after 10 000 consecutive charge–discharge cycles. A low charge transfer resistance value was confirmed using electrochemical impedance spectroscopy. A scalable and efficient method for creating high-performance supercapacitor electrodes is presented in this study. Additionally, the relationship between surface chemistry and structural order in affecting electrochemical performance is thoroughly examined, providing a fresh perspective on the future of innovative energy materials.