NiCo2S4/rGO composite electrode material derived from CO-based MOFs for high-efficiency hybrid supercapacitors

Abstract

The Co-based organic skeleton was combined with graphene oxide (GO) as a precursor, Ni2+ hydrolysis etching was introduced, and finally, NiCo-LDH was obtained. The final composite electrode material NiCo2S4/rGO was obtained by high-temperature vulcanization. The introduction of MOFs and rGO significantly increased the specific surface area of the material and made it have excellent electrochemical properties. The specific capacitance of the composite NiCo2S4/20rGO reaches an astonishing 2452.65 F g− 1 when the current density is 1 A g− 1. In addition, at a large current of 10 A g− 1, the specific capacitance of the material can also reach 1250 F g− 1, and after a long cycle of 5000 cycles at such a current density, the capacity remains at the original 73.2%. With NiCo2S4/20rGO electrode material as the positive electrode and activated carbon as the negative electrode, the hybrid supercapacitor is assembled. At an energy density of 56.9 Wh kg− 1, its power density reaches an excellent 799 W kg− 1, and it still has a capacity retention rate of 74% at a current density of 10 A g− 1. The excellent properties of composites demonstrated in this work open up new possibilities for high-quality energy storage devices.