Microwave-assisted in situ synthesis of reduced graphene oxide/Mn3O4 composites for supercapacitor applications

Abstract

Reduced graphene oxide/Mn₃O₄ (GM) composites were prepared by a simple and convenient strategy, that is, microwave irradiation of the hydrothermal product of reduced graphene oxide–Mn(NO₃)₂ mixtures. Mn₃O₄ nanoparticles with sizes of 20–50 nm were uniformly distributed on the surface of reduced graphene oxides. The GM composites exhibited good electrochemical performance with a specific capacitance of 344.8 F g⁻¹ at the discharge current density of 1 A g⁻¹ using 5 M NaOH as the electrolyte. The energy density of the GM composites was as high as 47.8 W h kg⁻¹ with a power density of 1000 W kg⁻¹. After 5000 cycles of charge/discharge experiments, a high level retaining specific capacitance of 342.1 F g⁻¹ was obtained with 99.2% retention of the initial capacitance at 1 A g⁻¹ and the equivalent series resistance of the GM composites system was much lower than that of pure Mn₃O₄. Therefore, the GM composites with large capacitance, good cycling performance and reversibility can be used as a promising electrode material for supercapacitor applications.