Ultrathin surface coating of conductive and zincophilic titanium oxynitride enables stable zinc anodes for aqueous zinc-ion batteries

The lifespan of aqueous zinc ion batteries (AZIB) has been hindered by the instability of zinc anodes, encountering challenges such as irregular dendritic growth, corrosion and hydrogen evolution reactions. In this study, we address these challenges by employing atomic-layer deposition (ALD) to create an ultrathin, conductive titanium oxynitride (TiN_xO_y) coating with abundant zincophilic sites. This atomic-scale coating serves as a bi-functional barrier that isolates the zinc metal from the electrolyte, thereby reducing spontaneous corrosion and mitigating hydrogen evolution. Additionally, the TiN_xO_y layer improves the distribution of the interfacial electric field and promotes uniform zinc plating and stripping. As a result, the TiN_xO_y-coated zinc anode demonstrates a significantly reduced over-potential and enhanced cycling stability, maintaining performance over 1300 h at 1 mA cm⁻² in a symmetric cell. When coupled with a MnO₂ cathode, the full cell achieves a capacity of 85.3 mAh g⁻¹ after 4500 cycles at a high current density of 10C.