Tuning Hydrazine Reduction Parameters to Engineer Porous rGO Hydrogel Electrodes for High-Performance Supercapacitors

Abstract

Graphene-based hydrogels are promising candidates for high-performance supercapacitor electrodes due to their 3D porous structure and large accessible surface area. In this study, reduced graphene oxide (rGO) hydrogels were synthesized via a one-step hydrothermal method using different concentrations of hydrazine hydrate (0.05–1 mL) and varying reduction times (12–24 h) to understand their combined effect on the material's electrochemical behaviour. The characterization methods such as XRD, FTIR, Raman, and FESEM confirmed the successful reduction and structural transformation of graphene oxide into a hydrogel network. Electrochemical testing revealed that the interplay between reducing agent concentration and reduction duration governs pore interconnectivity and ion diffusion, thereby critically determining the electrochemical performance of rGO hydrogels. The sample reduced with 0.1 mL hydrazine for 24 h exhibited an optimal porous architecture and delivered a high capacitance of 278 F/g at 1 Ag⁻1. Notably, lower hydrazine content led to more interconnected 3D pore networks, enhancing ion diffusion and charge storage. This work emphasizes the importance of fine-tuning reduction parameters to optimize rGO hydrogels for advanced energy storage applications.