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

We report on a hollow NiCoSe2/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 NiCoSe2 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 NiCoSe2/C are investigated, and the results indicate that the hollow NiCoSe2/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 NiCoSe2, the greatly enhanced electrochemical performances of the NiCoSe2/C can be due to the hollow nanostructure of NiCoSe2, 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.