Electrochemical Design of Reduced Graphene Oxide Supported Polyaniline–Metal Oxide Nanocomposites for Supercapacitor Applications

Abstract

Hybrid nanocomposites that integrate conducting polymers, metal oxides, and carbon frameworks offer a promising strategy for high-performance supercapacitor electrodes. In this work, reduced graphene oxide–supported polyaniline/metal oxide (ZnO, Fe₂O₃, and ZnFe₂O₄) nanocomposites were prepared and systematically investigated. The surface morphology, chemical composition, and structural and optical properties of the synthesized composites were systematically investigated using FE-SEM/EDX, AFM, UV–vis spectroscopy, and FTIR spectroscopy. Electrochemical performance was evaluated by cyclic voltammetry and electrochemical impedance spectroscopy, revealing typical pseudocapacitive behavior arising from synergistic faradaic contributions of PANI and metal oxides. Among the electrodes studied, rGO-supported PANI/ZnFe₂O₄ composite exhibited the best performance, delivering a competitive gravimetric specific capacitance of 294.13 F g⁻¹, an energy density of 163.5 Wh kg⁻¹, and a power density of 3658.5 W kg⁻¹, along with a capacitance retention of about 81% after 2000 cycles at a scan rate of 50 mV/s. The superior performance is attributed to the combined effects of improved conductivity from rGO, enhanced redox activity from the bimetal oxide, and reduced charge-transfer resistance, as confirmed by impedance analysis. These results demonstrate the combined interaction among rGO, PANI, and metal oxide nanoparticles, highlighting rGO-supported PANI/metal oxide composites as a highly promising platform for the development of high-performance supercapacitor electrodes.