In-situ formation of hierarchical solid-electrolyteerphase for ultra-long cycling of aqueous zinc-ion batteries

Aqueous rechargeable zinc ion batteries have received widespread attention due to their high energy density and low cost. However, zinc metal anodes face fatal dendrite growth and detrimental side reactions, which affect the cycle stability and practical application of zinc ion batteries. Here, an in-situ formed hierarchical solid-electrolyte interphase composed of InF3, In, and ZnF2 layers with outside-in orientation on the Zn anode (denoted as Zn@InF3) is developed by a sample InF3 coating. The inner ultrathin ZnF2 interface between Zn anode and InF3 layer formed by the spontaneous galvanic replacement reaction between InF3 and Zn, is conductive to achieving uniform Zn deposition and inhibits the growth of Zinc dendrites due to the high electrical resistivity and Zn2+ conductivity. Meanwhile, the middle uniformly generated metallic In and outside InF3 layers functioning as corrosion inhibitor suppressing the side reaction due to the waterproof surfaces, good chemical inactivity, and high hydrogen evolution overpotential. Besides, the as-prepared zinc anode enables dendrite-free Zn plating/stripping for more than 6,000 h at nearly 100% coulombic efficiency (CE). Furthermore, coupled with the MnO2 cathode, the full battery exhibits the long cycle of up to 1,000 cycles with a low negative-to-positive electrode capacity (N/P) ratio of 2.8.

Automated summary

In this study, a hierarchical solid-electrolyte interphase was developed on the zinc anode, which consisted of an inner ultrathin ZnF2 interface, metallic In layer, and outer InF3 layer. The ZnF2 interface promoted uniform zinc deposition and inhibited dendrite growth, while the metallic In and InF3 layers acted as corrosion inhibitors. The prepared zinc anode demonstrated dendrite-free zinc plating/stripping for over 6,000 hours and showed high cycle stability when coupled with the MnO2 cathode.