In-situ formation of hierarchical solid-electrolyte interphase 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.