ZnS-NiS Nanosheet Arrays Wrapped with Nanopetals of Ni(OH) as a Novel Core-Shell Electrode Material for Asymmetric Supercapacitors with High Energy Density and Cycling Stability Performance.

Supercapacitors possess minimum energy density, lower rate capability, and inferior long-term cycling stability performance, and these issues have restricted their practical applications. In these circumstances, supercapacitors based on a new class of hybrid nanomaterial are strongly desirable. Herein, for the first time, a complex nanoarchitecture comprised of a ZnS-NiS/Ni(OH) core/shell is constructed via a multistep hydrothermal process. The ZnS-NiS/Ni(OH) core/shell nanoarchitecture illustrates a commendable areal capacitance of 13.55 F cm at a lower current density value of 5 mA cm, respectively. The ZnS-NiS/Ni(OH) core/shell hybrid nanomaterial maintains a high cycling stability performance of 95.12% after a maximum 10 000 number of cycles. Moreover, the asymmetric supercapacitor device made up of ZnS-NiS/Ni(OH) and nitrogen-sulfur-codoped graphene nanosheets (NSGNs) delivers an ultrahigh energy density value of 68.85 W h kg at a power density of 700.16 W kg. The cycling stability of the ZnS-NiS/Ni(OH)//NSGN asymmetric supercapacitor was performed and was 91.79% after 10 000 GCD cycles. The ZnS-NiS/Ni(OH) core/shell hybrid electrode material has helped in promoting an asymmetric supercapacitor device with an elevated performance and can be considered as a potential electrode material to develop energy storage devices in the future.