In the pursuit of exploring superior energy storage systems, SrO-CNT nanocomposites were synthesized and studied as electrode materials for high-performance supercapacitors. The composites were prepared by a simple, economic ex situ methodology with different CNT ratios of (SrO)1−x(CNTs)x, (where x = 0, 0.25, 0.5, 0.75, 1). This compositional tuning enabled a systematic investigation of the role of CNTs in modifying the structural, optical, and electrochemical properties of the nanocomposites. Such an approach provides a practical route for identifying the optimum SrO-CNT composition for supercapacitor electrode applications. The crystallographic and optical characterization confirmed the formation of cubic SrO and hexagonal CNT phases and narrowing of bandgap due to enhanced electron interaction and quantum confinement effects. The incorporation of CNTs significantly improved electrical conductivity, ion diffusion, and surface reactivity with in the electrode matrix. The electrochemical evaluation showed that capacitance increases gradually with the increase in CNTs concentration. The composite of (SrO)0.25 (CNTs)0.75 exhibited a specific capacitance of 255F/g at 10 mV/s and 296 F/g at 0.3 A/g. The optimized electrode delivered an energy density of 14.3 Wh/kg, power density of 90 W/kg and demonstrated 76% capacitance retention, and 98% coulombic efficiency after 1500 charge–discharge cycles with an ESR of 0.403 Ω. These findings validate the strong synergistic interaction between the SrO and CNT networks toward the efficient and durable performance of energy storage devices. Overall, the results demonstrate that the optimized SrO-CNT nanocomposite is a promising low-cost electrode material for next-generation hybrid supercapacitor applications.
