<p>One of the primary concerns today is ensuring sustainable and uninterruptible electricity. Increasing the number of self-contained, high-capacity storage devices that use renewable energy sources is required. The supercapacitor (SCs) is a well-known storage technology that provides better stability, high charge and discharge rates, strong power density (P_d), and energy density (E_d). The electrode is an essential component of SCs, and in this case, a brownmillerite Ca₂Fe₂O₅ and rGO electrode were generated using a hydrothermal technique. The fabricated electrode material was physically characterization using a variety of methods, including X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier Transform infrared spectroscopy (FTIR). The electrochemical examination of the Ca₂Fe₂O₅/rGO nanocomposite in 3&#xa0;M KOH employed three electrodes. The investigation indicated cyclic stability at 3400th cycles a higher specific capacitance C_sp of 1271.87&#xa0;F g⁻¹ P_d of 795.6&#xa0;W kg⁻¹, and E_d of 124.23 Wh kg⁻¹ at 1&#xa0;A g⁻¹. The high efficiency of SCs applications is due to the mechanical flexibility, tight collaboration, and combined impact created by Ca₂Fe₂O₅/rGO. The Ca₂Fe₂O₅/rGO can be used as electrode for extraordinary SCs due to its enormous potential to generate green energy and its simplicity of one-step fabrication.</p>