NiCo2S4/carbon nanotube nanocomposites with a chain-like architecture for enhanced supercapacitor performance

A novel type of NiCo2S4/carbon nanotube (NCS/CNT) nanocomposite has been successfully prepared via a simple refluxing route without any surfactant and template. SEM and TEM observations confirm that the as-obtained NiCo2S4/CNT nanocomposites exhibit a necklace-like architecture, in which the NiCo2S4 particles are threaded with CNTs. As electrode materials for supercapacitors, the nanocomposites deliver an obviously pseudocapacitive behavior enhanced by a synergistic effect. When the loaded amount of CNTs is 10 mg (NCS/CNT-10), the maximum specific capacitance reaches up to 2210 F g(-1) at 1 A g(-1) and the specific capacitance can be maintained at 1949 F g(-1) at 1 A g(-1) after 14000 multi-rate charge-discharge cycles. By applying the NCS/CNT-10 composite as the positive electrode and activated carbon as the negative electrode, an asymmetric supercapacitor was fabricated with excellent electrochemical performance. Such a large enhancement of the electrochemical performance is attributed to the strong necklace-like architectures, which possess advantages such as high electric conductivity, good mechanical stability and excellent strain accommodation.