Hollow NiCoSe2/C prepared through a step-by-step derivatization method for high performance supercapacitors

Abstract

• Hollow NiCoSe 2 /C is synthesized through a step-by-step derivatization method. • The hollow nanostructure of NiCoSe 2 /C provides abundant channels for charge transfer. • The NiCoSe 2 /C electrode displays a capacity of 232.6 mAh g −1 at 1 A g −1 . • The NiCoSe 2 /C electrode shows excellent cyclic stability. • The hollow NiCoSe 2 /C might be a promising candidate used as electrode materials. We report on a hollow NiCoSe 2 /C prepared through a step-by-step derivatization method as high-performance supercapacitor electrode. Hollow nickel-cobalt bimetallic layered hydroxide (NiCo-LDH) derived from a typical zeolitic imidazolate framework (ZIF-67) was selenized to NiCoSe 2 via in situ selenylation, which was then coated with a layer of carbon via the hydrothermal method by using glucose as the carbon source. The electrochemical performances of the as-synthesized NiCoSe 2 /C are investigated, and the results indicate that the hollow NiCoSe 2 /C exhibits considerable specific capacity of 232.6 mAh g −1 at 1 A g −1 , good rate capability of 72.6% and high capacity retention of 88.3% after 5,000 cycles. Compared with ZIF-67, NiCo-LDH and NiCoSe 2 , the greatly enhanced electrochemical performances of the NiCoSe 2 /C can be due to the hollow nanostructure of NiCoSe 2 , enhanced electrical conductivity by the introduction of Se and C, and inhibited volume changes during the redox cycling from the protection of the carbon layer.