From Static Symmetry to Intrinsic Polarization: Engineering Dipole Fields in MnO 2 for Enhanced Zn 2+ Intercalation Kinetics and Structural Reversibility

ABSTRACT The centrosymmetric structure of layered δ‐MnO 2 cathodes severely restricts Zn 2+ transport kinetics in aqueous zinc‐ion batteries (AZIBs). Herein, we demonstrate a transition from static local symmetry to intrinsic polarization by engineering a built‐in dipole polarization field through Mo doping. This symmetry‐breaking strategy generates oriented Mo‐O‐Mn dipoles that self‐assemble into a continuous internal electric field, driving directional electron delocalization and enriching lattice oxygen with excess electron density. Consequently, the O p‐band center downshifts from −1.82 to −2.40 eV, reconfiguring the [MnO 6 ] octahedral electronic structure and substantially reducing the Zn 2+ diffusion barrier. The Mo‐modified MnO 2 (MMO) electrode delivers a reversible capacity of 348 mAh g −1 at 0.2 A g −1 with 95% retention over 200 cycles, and crucially, exhibits superior structural reversibility with reversible recovery of oxygen‐related species during cycling. This work establishes the O p‐band center as a key electronic descriptor and demonstrates intrinsic dipole‐field engineering as an effective strategy for improving Zn 2+ intercalation kinetics and structural reversibility in MnO 2 cathodes.