3D NiS dendritic arrays on nickel foam as binder-free electrodes for supercapacitors

In this work, we have successfully fabricated unique three-dimensional (3D) dendritic NiS nanosheet arrays on nickel foam (NiS–Ni) through a simple solution method, oxidizing fresh nickel foam under a heat treatment and following a sulfidation process without the need for any additional nickel sources, surfactant, or templates. The morphology of the NiS–Ni was observed by SEM and TEM, while the crystallinity was revealed by XRD pattern. When tested as the electrode for supercapacitors, the NiS dendritic arrays grown on nickel foam display excellent performance, demonstrating the specific capacity of 465.9 F g⁻¹ at the current density of 1 A g⁻¹. After 7000 cycles, the NiS–Ni electrode can maintain 101.79 % of its highest value, which demonstrates its superior cycle stability performance. Also, the NiS–Ni electrode exhibits high capacity retention when fast charging. These results establish that the NiS–Ni binder-free electrode exhibits greatly improved electrochemical performance with high capacitance and excellent cycling stability.