Constructing Compact Hybrid Buffer Interface via Ion Agglomeration Zone Electrolyte for Stable Zn Metal Battery

The extended-scale ion agglomeration zone (EIAZ) electrolytes are designed to regulate nanometer-scale solvation structures and inhibit water reactivity, while enable a compact hybrid buffer interface near the electrode surface via a collective ion transmission process and ionic co-opetition relationship, which is an indispensable premise for achieving stable interfacial reactions, such as facile de-solvation kinetics, dendrite-free deposition, and high tzn2+${{{\mathrm{t}}}_{{\mathrm{z}}{{{\mathrm{n}}}^{2 + }}}}$. Therefore, zinc-organic battery with high operating voltage demonstrates excellent stability under high mass loading (14 mg cm^‒2) and high DoD (25%) in EIAZ electrolyte, while the pouch cell can maintain a capacity of up to 26.1 mAh after 250 cycles, which is far better than the use of the conventional electrolyte.

Abstract

The development of aqueous Zn batteries is plagued by longevity limited at practical condition, due to the unstable electrode-electrolyte interface. Here, this work designs an extended-scale ion agglomeration zone (EIAZ) electrolyte to obtain anion combined with cation structures and reduce water activity. The electrolyte nanostructure features nanometer-scale depleted water zones in which ion pairs are densely packed together to form EIAZ, which facilitates compact hybrid buffer interface formed via a collective ion transmission process and ionic co-opetition relationship. The convergence and densification models of buffer interface for Zn surface is the result of cations adaptive adsorption that mitigates the concentration polarization of interfacial Zn²⁺ and prevents water contact with electrodes, constituting an indispensable premise for stabilizing both anode and cathode interface. Moreover, unique electrolyte nanostructure achieves Zn crystallographic optimization and fast interfacial reaction kinetics, generating ultralong cycling stability of 5500 h. Therefore, zinc-organic batteries can exert outstanding stability for over 3000 cycles and 1000 cycles under high current (10 A g^‒1) and high mass loading (14 mg cm⁻²). Impressively, pouch cell shows an excellent capacity retention of 99.8% with 26.1 mAh after 250 cycles. This study offers a novel perspective for designing electrolyte nanostructures and electrode interfaces for high-performance Zn batteries.