Formation of a Compact Carbonate Dominated Inorganic-Rich SEI for Durable Zinc Metal Battery

Aqueous zinc-ion batteries (AZIBs) are widely recognized as a promising candidate for energy storage owing to their intrinsic safety, environmental benignity, and low cost. Nevertheless, the unstable Zn/electrolyte interphase leads to uncontrolled dendritic growth, parasitic side reactions, and the accumulation of insulating byproducts, all of which hinder their practical deployment. Herein, we introduce a trace amount (0.5 vol%) of N-methylpyrrolidone as an efficient electrolyte additive to in situ construct an inorganic-rich solid electrolyte interphase (SEI) in a dilute ZnSO₄ electrolyte. The compact and uniform SEI layer on the Zn anode surface takes a role as a protective barrier that prevents direct contact between the electrode and the electrolyte, thereby suppressing corrosion and other parasitic reactions. As a result, the Zn||Zn symmetric cell exhibits highly reversible plating/stripping for over 200 h under a high areal capacity of 8  mAh cm^-2 (depth of discharge ~ 68.3%). This article provides a practical and scalable strategy for interfacial regulation in aqueous Zn systems and offers valuable insights into the rational design of electrolyte additives for high-performance AZIBs.