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

Cobalt nickel sulfide (CoNi2S4) has been extensively explored as an electrode material for supercapacitor. Nevertheless, bare CoNi2S4 is prone to agglomerate during the charge and discharge process, which limits its application. Herein, a novel CoNi2S4/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 CoNi2S4/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.