Rapid Microwave Hydrothermal Synthesis of NiCoMo Sulfide Nanosheet Arrays for Hybrid Supercapacitors

Transition-metal sulfides (TMS) are generally employed as suitable materials for electrodes in supercapacitors because of their abundance of electrochemical redox active sites, good structural flexibility, and superior conductivity compared to their oxide counterparts. However, the traditional hydrothermal approach for the synthesis of TMS is characterized by time-consuming reaction times, low yield, and limited capacity, which obstruct its large-scale implementation. Herein, a facile two-step microwave-assisted hydrothermal strategy was developed for rapidly synthesizing binder-free nickel cobalt molybdenum sulfide nanosheet array electrodes on top of carbon cloth (NiCoMoS/CC). The unique 3D layered structure endows NiCoMoS/CC with many accessible electroactive sites. Consequently, the optimized Ni2Co2Mo4S/CC electrode provided a substantial specific capacity value of 177.2 mAh g–1 (1 A g–1), while maintaining a high capacity of 130.6 mAh g–1 at 10 A g–1. Moreover, a hybrid supercapacitor (HSC) was fabricated by utilizing NiCoMoS/CC to be the cathode and an anode made from rotted Cucurbita pepo-derived activated carbon, achieving an energy density (Ed) value of 39.2 Wh kg–1 with a power density (Id) value of 783 W kg–1 and retaining 70.1% of the total capacity after undergoing 1000 cycles. This work offers strategies and prospects for developing low-cost, easily prepared, and binder-free TMS electrodes with high electrochemical characteristics.