Nickel foam-supported starfish-like Ni(OH)2@CoS nanostructure with obvious core-shell heterogeneous interfaces for hybrid supercapacitors application

The design and preparation of electrode materials with unique nanostructure are regarded as a significant strategy to increase the capacitance and cycling stability of energy storage devices. Herein, a starfish-like core-shell Ni(OH)(2)@CoS material grown on Ni foam (Ni(OH)(2)@CoS/NF, denoted as NOCS-1/NF) was successfully fabricated via a stepwise hydrothermal method. Benefiting from the unique starfish-like core-shell nanostructure, obvious and abundant heterogeneous interfaces, and good synergy between every component, the specific capacitance of the as-prepared Ni(OH)(2)@CoS-1/NF electrode can reach up to 981 F g(-1) at 1 A g(-1) and maintained 73.2% of initial value at a high current density of 10 A g(-1) in 2 M KOH aqueous solution. Moreover, a hybrid supercapacitor was prepared by using core-shell NOCS-1/NF as positive electrode and activated carbon coated on the NF (AC/NF) as negative electrode. The HSC delivered a high energy density of 17.9 Wh kg(-1) at a power density of 749 W kg(-1) and a satisfying cycling life with 90.1% capacitance retention after 4000 cycles. Eventually, two such devices in series successfully illuminated a red light-emitting diode. Meanwhile, this work probably provides a simple and convenient strategy to fabricate novel materials for the applicability of various energy-related fields. Graphic abstract

Automated summary

The study successfully fabricated a starfish-like core-shell Ni(OH)(2)@CoS material with unique nanostructure, which exhibited high specific capacitance and cycling stability at high current densities. The hybrid supercapacitor made with this material showed high energy density and satisfactory cycling life, capable of successfully lighting a red LED.