Facile synthesis of novel CoNi2S4/carbon nanofibers composite for high-performance supercapacitor

Cobalt nickel sulfide (CoNi 2 S 4 ) has been extensively explored as an electrode material for supercapacitor. Nevertheless, bare CoNi 2 S 4 is prone to agglomerate during the charge and discharge process, which limits its application. Herein, a novel CoNi 2 S 4 /carbon nanofibers composite has been developed via a facile hydrothermal process. The specific capacitance of the composite is as high as 1870 F g −1 at 4 A g −1 , when the current density increases to 10 A g −1 , the composite remains a high specific capacitance of 1650 F g −1 . The composite also delivers excellent cycling performance with a capacitive retention of 85.1% after 5000 cycles at 4 A g −1 . Moreover, the hybrid supercapacitor consisting of CoNi 2 S 4 /carbon nanofibers cathode and activated carbon anode shows a specific capacitance of 125.5 F g −1 at a current density of 0.5 A g −1 . The hybrid supercapacitor can also realize high energy density (45 Wh kg −1 at 400 W kg −1 ), suggesting the promising application in supercapacitor. • A novel CoNi 2 S 4 /carbon nanofibers composite was prepared via a facile process. • The specific capacitance of the composite is as high as 1870 F g −1 at 4 A g −1 . • The hybrid supercapacitor reaches high energy density of 45 Wh kg −1 at 400 W kg −1 . • The synergistic effect enhances the capacitive performance of the composite.