Tunneling Proton Grotthuss Transfer Channels by Hydrophilic‐Zincophobic Heterointerface Shielding for High‐Performance Zn‐MnO₂ Batteries

Abstract Hollandite‐type manganese dioxide (α‐MnO₂) is recognized as a promising cathode material upon high‐performance aqueous zinc‐ion batteries (ZIBs) owing to the high theoretical capacities, high working potentials, unique Zn²⁺/H⁺ co‐insertion chemistry, and environmental friendliness. However, its practical applications limited by Zn²⁺ accommodation, where the strong coulombic interaction and sluggish kinetics cause significant lattice deformation, fast capacity degradation, insufficient rate capability, and undesired interface degradation. It remains challenging to accurately modulate H⁺ intercalation while suppressing Zn²⁺ insertion for better lattice stability and electrochemical kinetics. Herein, proton Grotthuss transfer channels are first tunneled by shielding MnO₂ with hydrophilic‐zincophobic heterointerface, fulfilling the H⁺‐dominating diffusion with the state‐of‐the‐art ZIBs performance. Local atomic structure and theoretical simulation confirm that surface‐engineered α‐MnO₂ affords to the synergy of Mn electron t_2g–e_g activation, oxygen vacancy enrichment, selective H⁺ Grotthuss transfer, and accelerated desolvation kinetics. Consequently, fortified α‐MnO₂ achieves prominent low current density cycle stability (≈100% capacity retention at 1 C after 400 cycles), remarkable long‐lifespan cycling performance (98% capacity retention at 20 C after 12 000 cycles), and ultrafast rate performance (up to 30 C). The study exemplifies a new approach of heterointerface engineering for regulation of H⁺‐dominating Grotthuss transfer and lattice stabilization in α‐MnO₂ toward reliable ZIBs.