Hydrothermal Synthesis of alpha-MnS Nanoflakes@Nitrogen and Sulfur Co-doped rGO for High-Performance Hybrid Supercapacitor

The alpha-MnS nanoflakes/rGO sheets were obtained via a facile one-step hydrothermal approach using carbon disulfide as sulfur source, and ethylenediamine as a complexing agent which forms a complex with Mn2+ ions. Oil droplets of carbon disulfide and water are bridged via the hydrophobic/hydrophilic nature of ethylenediamine. alpha-MnS/rGO was successfully co-doped by nitrogen and sulfur by the action of ethylenediamine and CS2, respectively. The as-prepared material exhibits an excellent electrochemical performance with a remarkable specific capacitance of 700 F g(-1) at a current density of 1A g(-1), high rate capability of 66.65% retention at 20A g(-1) and superior cycling stability of 127% capacitance retention after 10000 cycles. To further explore the electrochemical performance of alpha-MnS/rGO, a hybrid supercapacitor device was assembled using the -MnS/rGO as a positive electrode and an activated carbon as a negative electrode. The fabricated device exhibits the highest energy density of 38.13Wh kg(-1) at a power density of 850W kg(-1) and still retains 21.25Wh kg(-1) at a power density of 17kW kg(-1). These superior results demonstrate that the alpha-MnS/rGO nanoflakes electrode can be considered as a promising material for high-performance supercapacitors.