Sputtered Ultra‐Thin TiO2 Interlayer for Highly Reversible Aqueous Zinc‐Ion Battery

ABSTRACT Undesirable side reactions at the Zn anode interface hindered the development of aqueous zinc‐ion batteries (AZIBs). In particular, the direct contact between the zinc (Zn) anode and aqueous media triggers side reactions such as Zn dendrites, hydrogen evolution, and corrosion. In this study, an artificial interlayer (TiO2) is constructed on the Zn anode surface by magnetron sputtering technology. Thanks to its ultra‐thin, uniform, and stable porous structure, the TiO2 interlayer can effectively suppress and reduce side reactions through a physical barrier and regulation of ion flux. The experimental results show that the Zn||Zn symmetric cells using Zn anode with TiO2 interlayer (TO‐Zn) exhibit symmetric charge–discharge curves and an ultra‐long cycle life of over 5100 h at 5 mA/cm2 (1 mA∙h/cm2), which is approximately 51 times longer than the bare Zn anode (only 100 h). Compared to the bare Zn||MnO2 full cell, the full cell assembled with TO‐Zn exhibits a relatively stable cycling performance, retaining a reversible capacity of approximately 108.4 mA∙h/g after 1000 cycles. This study uses a facile process technology to provide a reference for constructing an artificial interlayer.