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

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 SO₄ ^2- and participates in the formation of zinc hydroxide sulfates (ZHS). With no interference of H₂ 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.