<p>In the present study, Mn-doped CuO nanostructures (CuO: x% Mn; x = 2, 5, 10) are synthesized via a facile chemical precipitation method to systematically investigate the influence of dopant-induced structural and morphological modulation on electrochemical performance. Structural characterizations including XRD, Raman spectroscopy, FTIR, and XPS analysis revealed successful Mn incorporation into the CuO lattice. FESEM reveals a distinct morphology evolution from nanoflakes to nanorods with increased Mn concentration. This transformation enhances electrical conductivity, exposes abundant electroactive sites, and facilitates rapid electrolyte ion diffusion, thereby accelerating charge-transfer kinetics. BET surface area analysis further confirmed the mesoporous nature of these nanostructures, enabling efficient electrolyte penetration. Electrochemical measurements in 1&#xa0;M KOH demonstrate that the optimized 5% Mn-doped CuO electrode exhibited a specific capacitance of 334.2 F g⁻¹ at 10&#xa0;mV s⁻¹ and 163.84 F g⁻¹ at 5.5 A g⁻¹, with a capacitance retention of 119% after 5000 charge–discharge cycles. At higher doping level electrochemical performance decreased due to agglomeration and the formation of larger grains. Furthermore, an asymmetric supercapacitor device was assembled using Mn-doped CuO as the positive electrode and activated carbon as the negative electrode. The energy and power densities were calculated from GCD measurements using standard electrochemical relations for two electrode system. This exhibits enhanced energy density and power density, highlighting its strong potential for practical energy storage applications.</p>