Structural, morphological, and electrochemical properties of three-dimensional starfish-like NiO/r-GO nanocomposites for supercapacitor application

In the present work, starfish-like nanostructures of NiO/r-GO nanocomposite were prepared through a simple hydrothermal process. The prepared samples were used as a positive electrode (Ni-foam) with a binder of PVDF (polyvinylidene fluoride) for supercapacitors in a 3 M KOH aqueous electrolyte solution. The starfish-like NiO/r-GO-based electrode material delivered a high specific capacitance (specific capacity) of 574 F/g (220 Cg⁻¹) at the current density of 2 Ag⁻¹. Moreover, the cyclic stability and coulombic efficiency (GCD cycling performance) of the NiO/r-GO electrode showed 88% and 96% retention after 2000 cycles at the current density of 10 Ag⁻¹. The assembled NiO/r-GO//AC device delivered the potential window of 1.4 V and remarkable specific capacitance (capacity) of 76.3 F/g (37 C/g) at 1 A/g. The NiO/r-GO nanostructure exhibited good electronic and ionic conductivity, more electroactive sites, and the synergistic effect between NiO and reduced graphene oxide, which exhibits outstanding energy storage performance in supercapacitors.