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

The α-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. α-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 1 A g-1, high rate capability of 66.65% retention at 20 A g-1 and superior cycling stability of 127% capacitance retention after 10000 cycles. To further explore the electrochemical performance of α-MnS/rGO, a hybrid supercapacitor device was assembled using the α-MnS/rGO as a positive electrode and an activated carbon as a negative electrode. The fabricated device exhibits the highest energy density of 38.13 Wh kg-1 at a power density of 850 W kg-1 and still retains 21.25 Wh kg-1 at a power density of 17 kW kg-1. These superior results demonstrate that the α-MnS/rGO nanoflakes electrode can be considered as a promising material for high-performance supercapacitors. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim