Two-step electrodeposition synthesis of NiCo₂S₄/MoS_x composite on nickel foam as electrodes for supercapacitors

This work reports a simple, eco-benign, pollution-free two-step electrodeposition technology to prepare NiCo₂S₄/MoS_x composites on nickel foam (NF). It was then employed as electrodes for all-solid symmetric supercapacitors. The NiCo₂S₄/ MoS_x/NF composite can provide a superior specific capacity of 1494.52 F/g at 1 A/g, and also deliver good stability of ∼93.03% after 1000 cycles. The NiCo₂S₄/MoS_x/NF was assembled as the positive and negative electrodes of an all-solid symmetric supercapacitor (NiCo₂S₄/MoS_x/NF // NiCo₂S₄/MoS_x/NF). This assembly exhibits an energy density of 32.54 Wh/kg with the power density 285.72 W/kg, and superior cycle life retention rate of 84.46% and Coulombic efficiency of 100% after 1000 charge-discharge cycles, respectively. The excellent electrochemical property of the NiCo₂S₄/MoS_x/NF composite is ascribed to the synergistic effect between the MoS_x and NiCo₂S₄, suggesting it has excellent prospects as an electrode for supercapacitors.