Hierarchical nickel sulfide hollow spheres for high performance supercapacitors

Abstract

Hierarchical NiS hollow spheres assembled from ultrathin nanosheets are synthesized by an efficient template-engaged conversion method. Silica nanospheres were used as templates, and SiO2@nickel silicate core-shell nanostructures were first prepared. In the presence of Na2S, the nickel silicate shell completely transformed into NiS nanosheetsvia a hydrothermal treatment, accompanied by the total dissolution of the inner SiO2 core. This gives rise to uniform hollow nanospheres whose shells are assembled from ultrathin NiS nanosheets. In virtue of the large surface area and enhanced structural stability, the as-prepared NiS hollow spheres exhibit excellent electrochemical performance as electrode materials for supercapacitors.