Cobalt sulfide @ CNT-CNF for high-performance asymmetric supercapacitor

A cobalt sulfide encapsulated within carbon nanotube-carbon nanofiber (Co9S8@CNT-CNF) nanohybrid electrode is designed and prepared. The physicochemical characterization such as X-ray diffraction (XRD) and electron microscopy revealed the formation of Co9S8@CNT-CNF. The specific capacitance of Co9S8@CNT-CNF is 1656Fg(-1) at 1Ag(-1) with good electrochemical cycle stability (92.6% up to 10,000cycles). The Co9S8@CNT-CNF electrode exhibits a maximum power density of 8.83kWkg(-1) with an energy density of 65Whkg(-1), while a maximum energy density of 175Whkg(-1) is attained at a power density of 463Wkg(-1). This impressive electrochemical performance of the Co9S8@CNT-CNF composite indicated significant potential for application in high-power and energy-storage devices.