A renewable biomass-based lignin film as an effective protective layer to stabilize zinc metal anodes for high-performance zinc–iodine batteries

Abstract

Aqueous rechargeable zinc–iodine (Zn–I₂) batteries with high security and low cost have been considered as a promising candidate for energy storage instruments in recent years. Nevertheless, the commercial application of Zn–I₂ batteries is hampered by the shuttling of triiodide (I₃⁻) ions and the formation of Zn dendrites. Herein, in this work, renewable biomass-based lignin (L) with rich functional groups and a three-dimensional networked structure was constructed on metallic Zn anodes (Zn@L) as an effective protective layer. The presence of L on the Zn surface can suppress the corrosion of I₃⁻ and H₂O to stabilize the electrode/electrolyte interface and prevent the formation of Zn dendrites. The coordination interaction of oxygen-containing functional groups with Zn²⁺ and Zn metal contributes to generate the homogeneous protective films and the strong adsorption energy with metallic Zn, respectively. Zn@L symmetrical cells exhibited a long cycle life of 650 h at 2 mA cm⁻² with a fixed capacity of 2 mA h cm⁻² and a stable coulombic efficiency for up to 500 cycles, better than that of bare Zn. The full cells with Zn@L anodes and I₂ cathodes displayed ultrahigh cycle stability (high capacity retention of 99.7% after 35 000 cycles at 6 A g⁻¹). This work provides a promising strategy to protect Zn anodes by introducing renewable polymers as an effective surface coating layer and implement the high-value utilization of L waste.