Facile fabrication of carbon-coated spinel nickel–cobalt–sulfide hollow spheres to achieve high-performance supercapacitors

Abstract

This paper presents a simple method to prepare carbon-coated spinel nickel–cobalt–sulfide metal hollow spheres with excellent electrochemical properties, which can be considered as promising materials for supercapacitors. A type of Ni–Co coordination polymer sphere is identified as a precursor metal template as well; the prepared coordination polymer precursor sphere is vulcanized to obtain the NiCo₂S₄ hollow metal sphere. After that, glucose modified on the surface of the hollow metal sphere is the source of carbon. After hydrothermal sulfuration treatment the carbon-coated NiCo₂S₄ hybrid material is obtained, which is sintered in a tube furnace to improve the crystallinity of the materials. The compound materials reveal advanced specific capacitance (1367 F g⁻¹ at 1 A g⁻¹) and advantageous cycling stability (approximately 89.2% maintained after 6000 cycles at 10 A g⁻¹).