<p>The ongoing energy crisis and rapid industrialization have intensified the need for sustainable and cost-effective energy storage devices. Over the years, scientists have explored numerous electrode materials for supercapacitor applications. Among these, metal oxides have garnered significant attention due to their potential for high-performance energy storage. In this study, we report novel nanoneedle-structured Mn-doped NiCo₂O₄ electrode for electrochemical supercapacitor. A simple in-situ hydrothermal method was employed to synthesize Mn doped NiCo₂O₄ electrodes. The effect of physicochemical properties on doping was analyzed using various characterization techniques. X-ray diffraction (XRD) confirmed the formation of a single-phase spinel structure. Scanning Electron Microscopy (SEM) revealed a well-defined nanoneedle-like morphology. Energy-dispersive X-ray spectroscopy (EDX) confirmed the elemental composition and purity of the synthesized samples. Fourier-transform infrared (FT-IR) spectroscopy further validated the presence of tetrahedral and octahedral coordination sites. Electrochemical characterization was conducted using a three-electrode system in 1&#xa0;M KOH electrolyte. The Mn doped NiCo₂O₄ electrode exhibited an enhanced specific capacitance of 1377 Fg⁻¹ at a current density of 1 Ag⁻¹. Furthermore, a symmetric supercapacitor based on Mn doped NiCo₂O₄ demonstrated a high energy density of 21.8 Wh-kg⁻¹ at a power density of 500&#xa0;W-kg⁻¹. The device also exhibited excellent cyclic stability, highlighting the potential of Mn doped NiCo₂O₄ as a promising electrode material for supercapacitor applications. Compared to previously reported Mn-doped NiCo₂O₄ systems, this work demonstrates significantly improved performance, attributed to the unique nanoneedle morphology and optimized doping strategy.</p>