<p>Aqueous zinc-ion batteries (AZIBs) are regarded as promising candidates for new energy storage materials, due to their improved safety, lower cost, and higher energy density. Nevertheless, the paucity of cathode materials that combine outstanding rate performance and cycling stability is a significant factor hindering further development and application of AZIBs. The main persistent issues with MnO₂ cathode materials are their inherent structural delicacy and lack of adequate electronic conductivity. In this study, the efficacy of Co-doped δ-MnO₂ (Co-MnO₂) in enhancing the energy density and longevity of AZIBs is examined. Theoretical calculations also show that Co intercalation aids in increasing MnO₂ conductivity and lowering the Zn²⁺ migration barrier, thereby accelerating reaction kinetics. The cathode material was shown to exhibit excellent energy storage performance, including increased capacity of 278.5&#xa0;mAh&#xa0;g⁻¹ at 0.1&#xa0;A&#xa0;g⁻¹, as well as an extended lifetime (74.9% retention after 5000 cycle tests at 2.0&#xa0;A&#xa0;g⁻¹). This excellent performance is a consequence of the material’s greater activity at more active sites. The results of the study reveal important insights into cationic intercalation principles and will facilitate the development of MnO₂ materials as high-performance cathodes in AZIBs.</p> Graphical Abstract <p></p>