Cation‐Anion Synergistically Regulated Spatial‐Electronic Effects Enable a Highly Stable δ‐MnO ₂ Cathode for Aqueous Zinc‐Ion Batteries

ABSTRACT In the energy storage system of aqueous zinc‐ion batteries (AZIBs), δ‐MnO 2 features a layered structure favorable for Zn 2+ /H + co‐intercalation and a theoretical capacity of 308 mAh g −1 , making it a promising cathode material. However, narrow interlayer pathways, structural collapse during cycling, and poor conductivity restrict its practical performance. To address these bottlenecks, we designed a cation (Na + /K + /Ca 2+ ) and anion (F − ) co‐doped δ‐MnO 2 (NKCFMO). Using in situ/ex situ characterizations and theoretical calculations, we systematically investigated the structural‐electronic regulation mechanism induced by anion‐cation synergy. We clarified its role in enhancing structural stability and conductivity, accelerating Zn 2+ /H + intercalation/deintercalation kinetics, and optimizing electrochemical performance. Results show that NKCFMO delivers a maximum discharge capacity of 320.6 mAh g −1 at 0.3 A g −1 , along with outstanding long‐term cycling durability (166.6 mAh g −1 @ 86% @ 1.5 A g −1 ) and high energy density (438 Wh kg −1 ). Through gradient optimization of multi‐cations, we maximize the synergistic effect, providing theoretical support and a technical pathway for designing high‐performance manganese‐based cathodes for AZIBs.