Imidazole‐Pillared Ammonium Vanadate as a High‐Performance Cathode for Aqueous Zinc‐Ion Batteries

ABSTRACT Layered ammonium vanadates have attracted significant attention as promising cathode materials for aqueous zinc‐ion batteries (AZIBs) owing to their high mass‐specific capacity and rapid Zn 2+ transport kinetics, which benefit from low molecular weight and expansive interlayer spacing. However, their practical application is hindered by irreversible structural degradation caused by strong Zn 2+ /V─O electrostatic interactions and weak interlayer N─H···O hydrogen bonding. Herein, we report an organic imidazole‐intercalated (NH 4 ) 2 V 4 O 9 cathode where imidazole molecules function as robust structural pillars. This molecular pillar engineering strategy simultaneously expands the interlayer spacing and reinforces the host framework, effectively suppressing irreversible de‐ammonization and enhancing structural integrity for Zn storage. The optimized cathode exhibits exceptional electrochemical performance, including a high reversible capacity of 431.9 mAh g −1 at 0.5 A g −1 , outstanding cycling stability with 86.2% capacity retention after 5000 cycles at 10 A g −1 , and remarkable rate capability (155.6 mAh g −1 at 20 A g −1 ). This molecular‐level pillar engineering not only resolves the intrinsic structural instability of ammonium vanadates but also offers a universal strategy for designing high‐performance layered cathodes in next‐generation energy‐storage systems.