Manipulating Bilateral Interface Chemistry via Multifunctional Salt Additive for Durable Aqueous Zinc Batteries

Abstract

Sustainable aqueous zinc ion batteries are promising for large-scale renewable energy integration due to their safety and reliability. However, unstable interfaces formed on both cathodes and anodes during cycling cause serious side reactions and continuous structural degradation. Enhancing interface stability is crucial toward the practical application of zinc-metal batteries. This paper presents an electrolyte engineering interface (EEI) strategy, using a low-cost, environment-friendly ammonium sulfamate (AS) with electron-withdrawing groups into ZnSO₄ electrolyte as a self-sacrificial additive. The electron-donating effect promotes the formation of a lean-water and stable electrode/electrolyte interface, reducing concentration polarization and stabilizing the interface pH-value. This enables rapid zinc-ion transport and uniform deposition at the anode/cathode interfaces. Consequently, the assembled Zn||Zn symmetric battery achieves stable cycling for 1000 h at 57.0% depth of discharge and the Coulombic efficiency (CE) excesses 99.9%. Moreover, the AS additive is compatible with high-loading V/Mn-based cathodes. The Zn||NaV₃O₈ full battery with an N/P ratio of 3.14 maintains 88.84% capacity retention after 1000 cycles at 1 Ag^1-. As a proof of concept, the assembled 0.1 Ah Zn||MnO₂ pouch cell exhibits an average CE of 99.9% over 100 cycles at 0.15 C. This EEI strategy, by manipulating bilateral interface chemistry synchronously, offers a promising route for capable ZIBs.