Suppressing interfacial side reactions of zinc metal anode via isolation effect toward high-performance aqueous zinc-ion batteries

Aqueous zinc (Zn)-ion batteries (AZIBs) are one of the most promising large-scale energy storage devices because of the excellent features of zinc metal anodes, including high theoretical capacity (5,855 mAh·cm^–3 and 820 mAh·g⁻¹), high safety, and natural abundance. Nevertheless, the large-scale applications of AZIBs are mainly limited by the severe interfacial side reactions of zinc metal anodes, which results in low plating/stripping Coulombic efficiency and poor cycling stability. To address this issue, we report an artificial Ta₂O₅ protective layer on zinc foil (Ta₂O₅@Zn) for suppressing side reactions during Zn deposition/stripping. The results of density functional theory calculation and experiments indicate that Ta₂O₅@Zn anode can inhibit the side reactions between the electrolyte and zinc anode through the isolation effect. Benefiting from this advantage, the symmetric cells with Ta₂O₅@Zn anode delivered an ultralong lifespan of 3,000 h with a low overpotential at 0.25 mA·cm⁻² for 0.05 mAh·cm⁻². Furthermore, the full cells consisting of Ta₂O₅@Zn anode and MnO₂ or NH₄V₄O₁₀ cathode all present outstanding electrochemical performance, indicating its high reliability in practical applications. This strategy brings new opportunities for the future development of rechargeable AZIBs.