An in situ polymerized electrolyte layer via frustrated Lewis pairs enables aqueous Zn metal batteries with an ultrahigh accumulated capacity of 12 A h cm−2†

Aqueous zinc metal batteries (AZMBs) have garnered significant attention owing to the inherent safety of aqueous electrolytes and the zinc anode's high theoretical specific capacity (820 mA h g⁻¹). However, interfacial instability arising from rampant zinc dendrite growth and parasitic side reactions at the electrolyte/anode interface critically hinders practical implementation. Herein, we report an in situ solid electrolyte interphase (SEI) engineering strategy via frustrated Lewis pair (FLP)-mediated polymerization of 2-acrylamido-2-methylpropane sulfonic acid (AMPS), where FLP catalysis is achieved through synergistic interactions between metallic zinc and Zn²⁺ cations at the electrolyte/anode interface. In contrast to conventional electrolyte additives that rely on physical adsorption or chemical passivation, the polymerized AMPS (PAMPS) establishes a dual-functional interface: (i) rapid Zn²⁺ ion transport channels through sulfonic acid groups, and (ii) robust chemical bonding with zinc via acrylamide moieties. This unique architecture enables simultaneous regulation of Zn²⁺ flux homogeneity and interfacial stabilization. Accordingly, Zn‖Zn symmetric cells with the AMPS-containing electrolyte show stable cycling for 6500 h at 1 mA cm⁻². Notably, under extreme conditions (10 mA cm⁻², 10 mA h cm⁻²), the PAMPS-enabled anode achieves a coulombic efficiency of 99.7% and an unprecedented cumulative areal capacity of 12 A h cm⁻²—a fourfold improvement over state-of-the-art benchmarks. Additionally, the MnO₂‖Zn full cells with the AMPS-containing electrolyte exhibit a high specific capacity of 300 mA h g⁻¹ at 500 mA g⁻¹ and long cycling stability of 10 000 cycles at 1.58 A g⁻¹. This work offers a facile, economical and effective approach for designing a high-performance aqueous zinc metal battery for practical applications.