Remolding the Interface Stability for Practical Aqueous Zn/I 2 Batteries via Sulfonic Acid‐Rich Electrolyte and Separator Design

Abstract The electrolyte‐electrode interface plays a crucial role in aqueous Zn/I 2 battery and is largely determined by the properties of electrolyte and separator. Here, the synergistic effect of sulfonic acid‐rich electrolyte additive and separator impacts the interface stability of Zn/I 2 batteries is comprehensively investigated using operando synchrotron‐based Fourier‐transform infrared spectroscopy, cryo‐electron microscopy, and in situ spectroscopy. As a case study, a cost‐effective additive known as lignosulfonic acid sodium (LAS) and a flexible sulfonated polyether sulfone membrane are employed to facilitate the formation of a stable solid electrolyte interface (SEI) on the Zn anode and effectively…