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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. [ABSTRACT FROM AUTHOR]