<p>The remarkable electrical and electrochemical characteristics of manganese dioxide (MnO₂) and other metal oxide nanostructures have attracted a lot of interest in energy storage. These nanostructures can be doped with transition metals (Ni, Fe, and Co) to improve electrochemical stability, energy and power density, and electrical conductivity. Determining the charge storage capacity and efficiency of these doped nanostructures is influenced by their structural design. In this work, we examine how Co doping affects manganese dioxide (α-MnO₂) nanostructures' electrochemical performance for supercapacitor applications. The produced nanocomposite's structure has nano rod-like shapes and is evenly covered in Co metal nanoparticles. At a scan rate of 4 mVs⁻¹, the 5% Co-doped MnO₂ electrode demonstrated exceptional pseudocapacitive performance, achieving a high specific capacitance of 1012 Fg⁻¹. Additionally, it showed low impedance in comparison with the pristine equivalent and outstanding cycling stability, holding onto more than 80.2% of its initial capacitance after 5000 charge–discharge cycles. Improved electron transport, structural stability, increased surface roughness, and decreased grain size brought about by Co ion incorporation into the MnO₂ matrix are the primary causes of this enhancement in electrochemical performance. These results demonstrate Co-doped MnO₂ nanostructures' potential as electrode materials for high-performance supercapacitors.</p> Graphical abstract <p></p>