Trieffect Dense Organic‐Derived Coating Enabling Synergistic Bulk Stability and Interfacial Reactivity for Superb Zn‐Mn Batteries

The practical application of aqueous Zn‐MnO 2 batteries is hindered by sluggish Zn 2+ diffusion kinetics, severe Mn dissolution, and “dead” MnO 2 accumulation in Mn 2+ ‐containg electrolytes, leading to inferior rate capability and rapid capacity decay. Herein, we designed an organic‐modified MnO 2 uniformly encapsulated by 1,4‐dihydroxybenzene (HQ) to simultaneously regulate bulk stability and interfacial reactivity of HQ‐MnO 2 hybrid (denoted as H‐MnO 2 ) via a facile solvent‐free ball milling method. In/ex situ characterization and theoretical calculation results reveal that the dense HQ‐derived coating with Mn─O─C interfacial bonds significantly boost charge diffusion kinetics and improves the structural robustness of H‐MnO 2 . Furthermore, the redox‐catalytic HQ‐derived layer with C═O/C─OH couples efficiently promotes selective H + insertion ability as well as boosts cathodic Mn 2+ /MnO 2 conversion to prevent irreversible ZnMn 2 O 4 and “dead” MnO 2 accumulation simultaneously. As a result, the Zn//H‐MnO 2 battery exhibits an outstanding capacity of 575 mAh g −1 , superior rate performance, and ultra‐long lifespan over 15 000 cycles. Moreover, 192.5 Wh kg H‐MnO2 −1 pouch cell with practical high‐mass loading maintained 100% capacity retention after 130 cycles, demonstrating the effectiveness of trieffect‐integrated organic interfacial engineering for high‐energy and durable Zn‐MnO 2 systems.