In this work, the inherently low electrical conductivity of NiOOH was addressed by incorporating reduced graphene oxide (rGO) as a conductive additive, resulting in enhanced electron transport and superior practical capacitance. A binder-free two-step electrochemical deposition method was employed, where rGO was first deposited onto nickel foam (NF) via electrophoretic deposition, followed by galvanostatic growth of NiOOH nanoneedles and subsequent annealing. X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) confirmed the successful formation of NiOOH, while field-emission scanning electron microscopy (FESEM) revealed a nanoneedle-like morphology. To assess the electrochemical properties, a three-electrode cell containing a 2 M KOH solution was used. The results show that the rGO-supported NiOOH hybrid electrode exhibits a high specific capacitance of 1304 F g−1 at a current density of 1 A g−1. Furthermore, galvanostatic charge-discharge (GCD) measurements demonstrate excellent cycling stability, with a capacitance retention of 95.7% after 2000 cycles. In addition, the synthesized rGO-supported NiOOH hybrid electrode exhibits an impressive energy density of 45.3 Wh kg−1 at a power density of 916 W kg−1, highlighting its strong potential for a broad range of practical energy storage applications. These results indicate that the incorporation of rGO into the hybrid electrode structure facilitates rapid ion diffusion and reduces resistance at the electrolyte-electrode interface, thereby enhancing the electrochemical performance of the electrode material. Overall, the rGO-supported NiOOH hybrid electrode paves a new way for practical applications of supercapacitors in energy storage due to its cost and time efficiency, as well as its ease of preparation.
