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

Aqueous rechargeable zinc-iodine (Zn-I-2) 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-I-2 batteries is hampered by the shuttling of triiodide (I-3(-)) 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 I-3(-) 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 I-2 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.

Automated summary

This study demonstrates the use of renewable polymers as a surface coating layer to protect zinc anodes in zinc-iodine batteries, effectively suppressing triiodide ion shuttling and zinc dendrite formation. The results show that the introduction of renewable polymers significantly improves the stability and cycle life of the batteries.