Domain‐Pinned Ferroelectric‐Like Fields Drive Deep Zn 2+ Intercalation in Bi 2 TeO 5

ABSTRACT Traditional MnO 2 ‐ and V 2 O 5 ‐based frameworks remain among the most widely studied cathode systems for aqueous zinc‐ion batteries (AZIBs), yet persistent structural instability and sluggish Zn 2+ transport often result in severe polarization and capacity degradation during cycling. Herein, we report a domain‐pinned cathode platform based on Cr‐doped oxygen‐vacancy Bi 2 TeO 5 (Cr‐OvBTO). The synergistic combination of Cr/Ov engineering and the stereochemically active lone‐pair electrons of Bi 3+ and Te 4+ reconstructs localized ferroelectric‐like fields associated with electrostatic heterogeneity and built‐in potential gradients. Consequently, a more stabilized local electrostatic environment is established, thereby enhancing lattice stability during cycling. Contact potential difference mapping and migration‐barrier calculations reveal a 77 mV built‐in potential gradient and a substantially reduced Zn 2+ migration barrier from 0.75 to 0.34 eV, consistent with improved Zn 2+ transport kinetics. As a result, Cr‐OvBTO delivers reversible deep‐intercalation behavior (∼360 mA h g −1 ) together with stable high‐rate cycling performance, retaining ∼77% capacity over 2000 cycles at 2 A g −1 . More importantly, this work demonstrates that domain‐pinned ferroelectric‐like fields can transform deep Zn 2+ intercalation from a kinetically constrained process into a reversible and sustainable transport pathway.