Trace molecular chelation engineering of a self-healing hybrid interphase for highly stable aqueous zinc-ion batteries

Abstract

Aqueous Zn-ion batteries (AZIBs) hold potential for grid-scale storage due to their intrinsic safety and low cost, yet face critical irreversible anode degradation from dendritic proliferation and parasitic reactions. Here, we introduce a molecular chelation-driven interfacial engineering strategy using trace polyglutamate sodium (PS) to construct a dynamically self-healing hybrid interphase on Zn anodes. PS reorganizes interfacial water networks and chelates Zn²⁺, forming an adaptive hydrogel-like PS–Zn (PSZ) layer, which further in situ generates an inorganic solid–electrolyte interphase (SEI). This synergistic PSZ–SEI layer provides robust electrode shielding, precise hydration regulation, and continuous self-repair. Consequently, Zn‖Zn symmetric cells achieve >4500 h cycling, and Zn‖Na₂V₆O₁₆·3H₂O full cells exhibit stable cycling for 1000 cycles in coin cells and 180 cycles in pouch cells (N/P ratio = 1.62) under high cathode loading (∼12 mg cm⁻²). The universality of this approach is further demonstrated in Zn‖I₂ batteries over 5000 cycles. This ppm-level dynamic interface control resolves long-standing interfacial conflicts in practical AZIBs.