In Situ Microwave-Reduced Graphene Oxide Composite Electrodes for Supercapacitors

Graphene, serving as an electrode material for supercapacitors, possesses a high specific surface area, excellent electrical conductivity, and robust mechanical properties. However, its practical application encounters challenges, notably, the agglomeration of graphene. van der Waals forces induce the aggregation of graphene sheets, consequently reducing the surface area and active sites and thereby deteriorating the electrochemical performance. van der Waals forces induce the aggregation of graphene sheets, consequently reducing the surface area and active sites and thereby deteriorating the electrochemical performance. This study systematically optimizes the microwave processing parameters to realize the homogeneous dispersion of reduced graphene oxide in composite electrodes via in situ microwave reduction. Through a comprehensive approach that combines multiscale morphological characterization and electrochemical performance analysis, clear structure–property relationships regulated by the microwave processing conditions are established. The results reveal that a microwave power of 300 W with an irradiation duration of 25 s forms the optimal processing window. Under this condition, the in situ gas evolution during microwave-assisted reduction induces the structural expansion of the graphene oxide layers, leading to a remarkable increase in the specific surface area (2185.34 m2·g–1) and an enhancement in the ion transport kinetics. Electrochemical impedance spectroscopy shows a substantial reduction in the charge transfer resistance, indicating a remarkable improvement in the electronic conductivity. Importantly, the in situ microwave reduction process effectively mitigates the restacking of graphene sheets, resulting in exceptional cycling stability (with 97.35% capacitance retention after 10,000 cycles) and outstanding rate capability. This work proposes an innovative strategy that synergistically combines in situ microwave reduction and dispersion optimization, providing new insights into the design and fabrication of high-performance composite electrode materials.