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

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.