<p>Ordered NiCo₂O₄/rGO nanowire arrays (NWAs) grown on a Ni foam substrate were synthesized using a template-free hydrothermal method and employed as an electrode with outstanding electrochemical properties for supercapacitors. After conducting a series of time-variable controlled experiments, the structure, morphology, and electrochemical properties of NiCo₂O₄/rGO NWAs were analyzed to find the most suitable growth time. Benefited from such unique array architectures, the designed NiCo₂O₄/rGO NWAs electrode demonstrates significant electrochemical properties, showing a specific capacitance of 2418 F·g⁻¹ at a charge-discharge current density of 1 A·g⁻¹. Moreover, it demonstrates exceptional stability, maintaining a capacity retention of 81.5% after undergoing 2,000 cycles, even when subjected to a current density of 10 A·g⁻¹. The reason of high stability is that the spacing between the nanowire arrays is large and the diffusion resistance of the electrolyte is significantly reduced, which facilitates the diffusion of the electrolyte into the interior of the electrodes and establishes an effective contact with the surface of the nanowires. Furthermore, the NiCo₂O₄/rGO nanowire array grows directly on the Ni foam without binder, which establishes rapid electron transport pathways on the Ni foam substrate, resulting in excellent electrochemical properties.</p>