<p>One important area of study that needs to be addressed right now is the development of energy storage systems with high energy density (E_d) and broad stability. Given these needs, it was important to note that supercapacitors (SCs) show a lot of promise as workable solutions for meeting these needs. To verify the crystallinity, morphological, functional group, and elemental composition of the produced hybrid material, it was physically characterized using a variety of methods, including X-ray diffraction, scanning electron microscopy, Fourier Transform infrared spectroscopy, and energy dispersive X-ray spectroscopy. An electrochemical investigation of Bi-doped ZnFe₂O₄ was examined, which confirmed the specific capacitance (C_sp) of 1537.03 F g⁻¹ obtained at 1 A g⁻¹. Also, Bi-doped ZnFe₂O₄ demonstrates 109.80 Wh kg⁻¹ energy density (E_d) and 680.4 W kg⁻¹ power density (P_d) and outstanding stability inside 3.0 M KOH across 10000^th cyclic CV studies. The R_s values of the undoped ZnFe₂O₄ and Bi-doped ZnFe₂O₄ are 0.85 Ω and 0.74 Ω, consequently. The better electrochemical efficiency is achieved by the Bi-doped ZnFe₂O₄ material’s higher surface area (52 m² g^-1) evaluated to ZnFe₂O₄ (37 m² g^-1), broad active area, and reduced resistance. Our study has confirmed that the produced substance can improve the spinel-structured transition-metal oxides’ capacitive qualities in newly developed energy storage devices.</p> Graphical Abstract <p></p>