Facile synthesis of hybrid CNTs/NiCo ₂S ₄ composite for high performance supercapacitors

Abstract

In this work, a novel carbon nanotubes (CNTs)/NiCo ₂S ₄ composite for high performance supercapacitors was prepared via a simple chemical bath deposition combined with a post-anion exchange reaction. The morphologies and phase structures of the composites were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy (Raman), X-ray photoelectron spectroscopy (XPS) and low-temperature sorption of nitrogen (BET). The electro-chemical tests revealed that the CNT/NiCo ₂S ₄ composite exhibited high electrochemical performance, because the CNTs were used as a conductive network for the NiCo ₂S ₄ hexagonal nanoplates. Compared with pure NiCo ₂S ₄ and the mechanically mixed CNTs/NiCo ₂S ₄ composite, the CNTs/NiCo ₂S ₄ composite electrode material exhibited excellent supercapacitive performance, such as a high specific capacitance up to 1537 F/g (discharge current density of 1 A/g) and an outstanding rate capability of 78.1% retention as the discharge current density increased to 100 A/g. It is therefore expected to be a promising alternative material in the area of energy storage.