Large-scale synthesis of cobalt sulfide/carbon nanotube hybrid and its excellent electrochemical capacitance performance

• Cobalt sulfide/carbon nanotube hybrid was large-scale prepared.
• Cobalt sulfide/carbon nanotube hybrid showed high specific capacitance.
• Cobalt sulfide/carbon nanotube hybrid exhibited high stability.

In this paper, cobalt sulfide (CoS) in-situ hybridized with carbon nanotube (CNT) is achieved through a hydrothermal process with the presence of polyvinylpyrrolidone (PVP). The morphology and structure of CoS/CNT hybrids are investigated by using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The results show that the product consists of CoS nanoparticles with the diameter of 30–50 nm that well dispersed on the outer surface of CNTs. Furthermore, CoS/CNT hybrid has shown excellent electrochemical capacitance and exhibited favorable electrochemical cycling stability with 93.4% capacitance retention over 1000 cycles. Therefore, the CoS/CNT hybrids can be considered as promising electrode materials for supercapacitor.