Aqueous zinc-ion batteries suffer from rapid decay under practical conditions due to bilateral Zn²⁺/Mn²⁺ ionic crosstalk, a system-level failure mechanism. We develop a hierarchical fluorinated polymer separator that regulates ion fluxes and stabilizes both electrodes simultaneously. This strategy enables extended cycle life while maintaining capacity, establishing ion flux regulation as a key design principle for durable zinc-based energy storage systems.

ABSTRACT

Aqueous Zn//MnO₂ batteries hold significant promise for safe and cost-effective large-scale energy storage, yet their practical deployment is hindered by rapid performance degradation. Here, we identify bilateral ionic crosstalk, a previously overlooked failure mechanism driven by active ion, as a root cause of electrode degradation. We demonstrate that excess Zn²⁺ migrating from the anode induces irreversible phase transitions at the MnO₂ cathode, forming electrochemically inert Zn_x(MnO₂)_y phase (ZMO sclerosis). Concurrently, dissolved Mn²⁺ from the cathode exacerbates corrosion and dendrite growth on the Zn anode. To mitigate this crosstalk, we design a hierarchical fluorinated polymer separator (HFPS). Such HFPS enables selective cation coordination and guides ion transport, achieving simultaneous regulation of Zn²⁺ and Mn²⁺ fluxes. This targeted regulation effectively mitigates ionic crosstalk and stabilizes both electrodes. Batteries employing the HFPS exhibit exceptional cycling stability, retaining 97% capacity after 1,000 cycles at 0.5 A g⁻¹ with stable operation exceeding 500 h. This performance represents a 54% lifespan enhancement over state-of-the-art aqueous counterparts. Our work provides a fundamental mechanistic understanding of active-ion-induced failure and establishes ion flux regulation as a universal design strategy for durable aqueous zinc-ion batteries.