Hydrogen Atom Capture Toward Dense Solid Electrolyte Interface for Long‐Cycling Aqueous Zinc‐Ion Batteries

Abstract Aqueous zinc‐ion batteries (AZIBs) are promising high‐safety energy storage devices, but their practical implementation has been limited by dendrite growth and hydrogen evolution reaction (HER). Solid‐electrolyte interface (SEI) is expected to address these problems. Herein, we revealed that HER results in loose and porous interfacial structure, making the in situ construction of reliable SEI a challenge. Thus, a universal and effective hydrogen atom scavenging strategy is proposed to in situ construct a dense and uniform inorganic SEI by introducing potassium persulfate (PSS). PSS scavenges the adsorbed hydrogen atoms, thus inhibiting HER. Meanwhile, PSS is reduced into SO 4 2− and participates in the formation of zinc hydroxide sulfates (ZHS). With no interference of H 2 bubbles on ZHS crystallization, an ideal SEI is constructed. This ZHS‐SEI exhibits superior electronic insulation, effectively suppressing further HER and Zn dendrite growth during cycling. As a result, the Zn//Zn symmetric cell with PSS can achieve stable Zn plating/stripping for 1882 h at 5 mA cm −2 and 2.5 mAh cm −2 and 650 h at 10 mA cm −2 and 5 mAh cm −2 , respectively. The cycling stability of the Zn||NVO full cell is also significantly improved at 5 A g −1 . This work provides a novel perspective for stabilizing the zinc anode interface.