Identifying A Multifunctional Fe‐N‐C Suspended Mediator with Cascade Regulatory Ability for Enhanced Aqueous Zn‐MnO ₂ Batteries

Abstract Anode, electrolyte, and cathode are the most critical components that determine the performance of aqueous zinc‐ion batteries. However, all of them have their own shortcomings in practical applications, most of developed strategies typically focus on only a single component, failing to achieve overall balanced regulation. Herein, a new design concept of multifunctional Fe‐N‐C suspended electrolyte with “cascade regulation” capability is proposed. The Fe‐N‐C suspended mediator fully integrates the advantages of distinct active sites, synergizing with each other to achieve cascaded regulation of the anode, electrolyte, and cathode. In detail, its functionalities include Lewis acid‐base interactions to immobilize SO 4 2− , alleviating concentration polarization of Zn anode interface, promoting desolvation, inhibiting Mn dissolution, and reversible deposition‐dissolution of by‐products. Benefiting from these synergistic effects, an impressive 3700 h cycle lifespan of the Zn symmetrical cell is achieved at the conditions of 1 mA cm −2 and 1 mAh cm −2 , exhibiting highly reversible deposition/stripping behavior. Furthermore, the assembled Zn‐MnO 2 battery retains a capacity of 194.9 mAh g −1 after 1000 cycles at 1 A g −1 (2.6 times higher than pure ZSO system on capacity retention rate). The strategy of achieving cascade regulation through synergistic interactions among components paves a new avenue for high‐performance aqueous Zn‐ion batteries.