<p>The recycling of end-of-life nickel–metal hydride (Ni–MH) batteries offers an attractive pathway to recover valuable metals and convert them into functional materials for energy storage. In this work, nickel hydroxide was recovered from spent Ni–MH batteries through an acid-leaching and alkaline precipitation process, followed by thermal conversion to NiO. The recovered NiO was integrated with reduced graphene oxide (rGO) via a reflux-assisted method to obtain an rGO/NiO nanocomposite electrode. Structural and morphological analyses confirmed the formation of crystalline NiO uniformly anchored to conductive rGO sheets, yielding a high specific surface area of 289.6&#xa0;m²g^-1. Electrochemical measurements performed in a three-electrode configuration revealed pronounced pseudocapacitive behavior associated with reversible Ni²⁺/Ni³⁺ redox reactions. The rGO/NiO electrode delivered a high specific capacitance of 2256.1 Fg^-1 at 1 Ag^-1 with a low charge-transfer resistance of 3.77 Ω. The device, an asymmetric supercapacitor (ASC), was fabricated with rGO/NiO as the positive electrode and activated carbon as the negative electrode. The assembled rGO/NiO//AC device achieved a specific capacitance of 657 Fg^-1 and an energy density of 44.7 Whkg^-1 at a power density of 348 Wkg^-1, calculated based on the total mass of active materials in both electrodes. The device also exhibited excellent cycling stability, with 97.6% capacitance retention after 10,000 cycles. These results demonstrate that nickel recovered from spent batteries can serve as a promising precursor for high-performance supercapacitor electrodes.</p>