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.