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 & BULL;cm(-3) and 820 mAh & BULL;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 & BULL;cm(-2) for 0.05 mAh & BULL;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.