High Performance Asymmetric Supercapacitor Based on Ni x S y /MoS2 Nanoparticles

A two-step strategy is developed to synthesize a Ni x S y (Ni3S4 and NiS2)/MoS2 hybrid nanomaterial, which is utilized as a high performance electrode. The best loose structure of this hybrid nanomaterial benefits ion diffusion. Utilized as an electrode, the as-synthesized electrode delivers a high specific capacity (169.44 mAh g–1 at 1 A g–1) and excellent cycling stability (≈88.24% capacity retention after 8000 charge–discharge tests). Most significantly, an asymmetric supercapacitor (ASC) device was constructed from this efficient electrode material, which could also reach an excellent energy density (306 W h kg–1 at a power density of 12.24 KW kg–1) and outstanding cycling stability (≈92.31% capacity retention even after 10 000 cycles). The high power density and energy density could facilitate fast charge and discharge, as expected, and the combined two ASC devices in series could power four red light-emitting diode (LED) bulbs for 16 min, and subsequently light one red LED bulb for 5 min, confirming its possible practical application. This general method provides a simple and cost-effective way to design the metal sulfides hybrid electrode, which could be applied in the field of energy storage.