ABSTRACT Flexible aqueous zinc‐based batteries (ZBs) are promising for wearable electronics but are hindered by low operating voltage and poor cycling stability. While zinc hexacyanoferrate (ZnHCF) represents a promising cathode candidate, its practical application is limited by rapid capacity decay. This failure is conventionally attributed to irreversible structural collapse. Herein, our findings depart from the prevailing view by demonstrating that degraded cathodes retain their structural integrity and recover capacity in specific media. We identify the primary failure mechanism as Zn 2+ entrapment induced by strong electrostatic interactions, distinct from lattice dissolution. Leveraging this insight, a dual‐regulation strategy is proposed utilizing Na + co‐intercalation to mitigate ion trapping and a quasi‐solid composite hydrogel to suppress water activity. Consequently, a high full‐cell voltage (1.8 V) Zn//ZnHCF battery is developed delivering exceptional stability over 4000 cycles. This work not only revises the fundamental understanding of ZnHCF degradation but also provides a robust pathway for high‐performance aqueous energy storage.