Facile design and synthesis of nickle-molybdenum oxide/sulfide composites with robust microsphere structure for high-performance supercapacitors

This study has reported a simple strategy for the fabrication of nickle-molybdenum oxide/sulfide composites (Ni-Mo-O-S) with microsphere structure, using a simple two-step method including a facile hydrothermal process and a post solution sulfidation treatment. The electrochemical performance of the as-prepared Ni-Mo-O-S composites is carefully evaluated as the working electrode. Additionally, the effects of material preparation conditions on the specific capacitance of the as-prepared composites are also fully investigated and summarized, including the S²⁻ concentration, sulfidation temperature and reaction time. In this work, high-performance electrode materials could be easily achieved under a wide range of preparation conditions. Specifically, the Ni-Mo-O-S composites could deliver a high specific capacitance of 2177.5 F·g⁻¹ at a current density of 1 A·g⁻¹, and after cycling for 5000 times, the specific capacitance could retain 86.25% of its initial value. Besides, the corresponding hybrid supercapacitor (Ni-Mo-O-S//AC HSC) achieves a high energy density of 50.61 Wh·kg⁻¹ at a power density of 850 W·kg⁻¹, and possesses excellent longterm electrochemical cycling stability (93.38% capacitance retention after 10,000 cycles). Our work has provided a low-cost, feasible and promising way to prepare high-performance electrode materials for supercapacitors.