MOF-derived self-sacrificing route to hollow NiS2/ZnS nanospheres for high performance supercapacitors

Abstract

Transition metal sulfides have complex valence states and exhibit excellent properties and promising applications in supercapacitors. NiS₂/ZnS hollow spherical nanocomposites have been successfully synthesized via a facile MOF-derived self-sacrificing route. The synthesis process involves solvothermal method for preparation of Ni/Zn–BDC MOF and subsequently chemical sulfidation treatment to convert into NiS₂/ZnS hollow nanospheres. When evaluated as electrode materials in supercapacitor, the NiS₂/ZnS hollow nanospheres exhibit high capacitance of 1198 F g⁻¹ at the current density of 1 A g⁻¹. Moreover, an asymmetric supercapacitor based on NiS₂/ZnS hollow nanospheres as the positive electrode and activated carbon (AC) as the negative electrode achieves an energy density of 28.0 W h kg⁻¹ at a power density of 478.9 kW kg⁻¹. The results suggest the NiS₂/ZnS hollow nanospheres are promising electrode materials for high-performance supercapacitors.