Reduced Graphene Oxide/Polypyrrole (rGO/PPy) Nanocomposite Optimization and Electrochemical Performance for High-Performance Supercapacitors

Abstract

The present study discusses the successful synthesis of a series of reduced graphene oxide/polypyrrole (rGO/PPy) nanocomposites using an in situ oxidative polymerization method. The focus of the evaluation was on their performance as electrode materials for supercapacitor applications, with assessments conducted using cyclic voltammetry (CV). Specifically, the investigation aimed to elucidate the impact of varying PPy content on the electrochemical characteristics of the rGO/PPy system. Four distinct composites were analyzed, characterized by differing PPy loadings, rGO/PPy5, rGO/PPy10, rGO/PPy15, and rGO/PPy20, measured at a scan rate of 10 mV s⁻¹. The CV profiles revealed quasi-rectangular shapes with pronounced redox peaks, thus confirming the presence of both electric double-layer capacitance (EDLC) and pseudocapacitance within the composite structure. The specific capacitance values were measured at 115.66, 89.20, 230.36, and 189.93 F g⁻¹ for rGO/PPy5, rGO/PPy10, rGO/PPy15, and rGO/PPy20, respectively. Notably, the rGO/PPy15 composite exhibited the highest capacitance, indicating an optimal loading of PPy that promotes efficient charge transfer, enhanced ion diffusion, and optimal utilization of electroactive sites. Lower concentrations of PPy resulted in inadequate redox contributions, while excessive PPy content obstructed the rGO conductive network, impeding charge transport. The observed synergistic interaction between the highly conductive rGO framework and the redox-active PPy matrix facilitates superior charge storage capabilities and stability. In conclusion, this study demonstrates that the optimization of PPy content within rGO/PPy composites significantly enhances their electrochemical performance. The rGO/PPy15 formulation stands out for its excellent combination of high capacitance, substantial reversibility, and robust structural integrity, thereby positioning it as a promising candidate for next-generation high-performance supercapacitor devices.