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 Mn 2+ 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 CS 2 , 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.