Tannic acid assisted metal-chelate interphase toward highly stable Zn metal anodes in rechargeable aqueous zinc-ion batteries

Aqueous zinc-ion batteries (AZIBs) have attracted extensive attention because of their eco-friendliness, intrinsic safety, and high theoretical capacity. Nevertheless, the long-standing Zn anode issues such as dendrite growth, hydrogen evolution, and passivation greatly restrict the further development of AZIBs. Herein, a metal-chelate interphase with high Zn affinity is constructed on the Zn metal surface (TA@Zn) via dipping metallic Zn into a tannic acid (TA) solution to address the aforementioned problems. Benefiting from the abundant hydrophilic and zincophilic phenolic hydroxyl groups of TA molecules, the metal-chelate interphase shows strong attraction for Zn2+ ions, guiding uniform zinc deposition as well as decreasing Zn2+ migration barrier. Therefore, the TA@Zn anode displays an extended lifespan of 850 h at 1 mA cm-(2), 1 mAh cm(-2) in the Zn|Zn symmetrical cell, and a high Coulombic efficiency of 96.8% in the Zn|Ti asymmetric cell. Furthermore, the Zn|V2O5 full cell using TA@Zn anode delivers an extremely high capacity retention of 95.9% after 750 cycles at 2 A g-(1). This simple and effective strategy broadens the interfacial modification scope on Zn metal anodes for advanced rechargeable Zn metal batteries.

Automated summary

By constructing a metal-chelate interphase with high Zn affinity on Zn metal surface, uniform zinc deposition is guided and Zn2+ migration barrier is decreased, resulting in extended lifespan and high Coulombic efficiency of the Zn anode.