High-performance NiSe2-CoS electrodes for sustainable energy storage in hybrid supercapacitors

Development of high-performance supercapacitors that have better energy storage capacity is necessary in meeting the needs of the future energy storage technologies. NiSe 2 -CoS composite electrode was also produced and incorporated in an asymmetric supercapacitor structure using activated carbon (AC) as negative electrode. The NiSe 2 -CoS||AC device was able to operate steadily over a potential window of 1.5 V with better electrochemical characteristics being shown by the synergistic interaction between NiSe 2 and CoS being observed in electrochemical impedance spectroscopy (EIS) analysis where minimal internal resistance was observed and therefore efficient electron and ion movement within the electrode material. The NiSe 2 -CoS||AC supercapacitor has been found to be a good candidate to be used in high-performance supercapacitors in the future; this is because of its high capacitance, rate efficiency, and high stability of its operation during discharge-charge cycles, which resulted in a high energy density of 66.3 Wh/kg at a power density of 3665 W/kg. This work demonstrates that NiSe 2 -CoS nanocomposites are strong contenders for use in future high-performance supercapacitor systems, due to their excellent energy storage capability, rate efficiency, and long-term operational reliability.