Improved chemical precipitation prepared rapidly NiCo ₂ S ₄ with high specific capacitance for supercapacitors

Abstract

Abstract In this work, rapid chemical precipitation assisted annealing method is used to prepare flower-like NiCo 2 S 4 . And the flower-like structure after polyethylene glycol (PEG) modification yields an excellent specific capacitance (2198.9 F g −1 at 1 A g −1 ). And an asymmetric supercapacitor assembled with NiCo 2 S 4 (PEG-modified) and activated carbon (AC) shows an energy density of 38.2 Wh kg −1 at 400 W kg −1 , and outstanding stability (80% remained after 3000 cycles at 5 A g −1 ). Benefited by a larger specific surface area and suitable pore size of the aggregate structure, the specific capacitance of prepared NiCo 2 S 4 is increased by about 2 times. This uncomplicated preparation method is proved to be suitable for NiCo 2 S 4 with a high specific capacitance of supercapacitors.