Direct electrochemical growth of amorphous molybdenum sulfide nanosheets on Ni foam for high-performance supercapacitors.

Crystalline molybdenum sulfides (MoS) have gained much attention as electrode materials for supercapacitors due to their specific atomic structure and high theoretical specific capacitance. However, poor electric conductivity and few accessible active sites as well as strictly controlled synthetic processes limit their capacitive performances. In this work, amorphous MoS (a-MoS) nanosheets with porous structure was directly grown on Ni foam by a simple and low-cost electrodeposition technique. By using a-MoS/Ni foam directly as the electrode material for supercapacitor, a high specific capacitance of 463 F/g was achieved at 1 A/g with good cycling stability at high rate. The isotropic and porous natures as well as ion reservoir function of the amorphous phase offers abundant active sites, transportation channels for ions and large electrode/electrolyte contact area, ensuring facile electrolyte diffusion within the active material. The strong adhesive of electrodeposited material to the underlying Ni foam substrate constructs an effective electron transport channel during the charging and discharging process. This work highlights the importance of electrodeposited amorphous MoS for potential application in supercapacitors.