Tetraethyl orthosilicate steam induced silicon-based anticorrosion film enables highly reversible zinc metal anodes for zinc-iodine batteries

Zinc (Zn) metal anodes are badly troubled by the challenges of notorious dendrites and corrosion reactions from H₂O and I₃⁻ ions during stripping/plating processes, impeding the commercial application of Zn-iodine (I₂) batteries. In this work, we report a novel strategy for the in-situ construction of uniform silicon-based anticorrosion films on Zn metal anodes (Zn@Ts) through the treatment of tetraethyl orthosilicate (TEOS) steam on Zn disks for different times. TEOS can be decomposed into three-dimensional (3D) porous inorganic frameworks (SiO_xC_y) filled with organic polymers (SiC_xO_yH_z) on Zn metal at 180 °C in autoclave. On the one hand, silicon-based composite layers can protect Zn metal from direct contact with aqueous electrolyte and stabilize the electrode/electrolyte interface, which hinders the occurrence of hydrogen evolution as well as corrosion reactions. On the other hand, 3D macroporous structure not only provides strong mechanical framework but also guides Zn²⁺ flux to homogenize Zn²⁺ concentration and realize uniform Zn nucleation/deposition, which contributes to suppress the growth of Zn dendrites. Zn@Ts symmetric batteries exhibit better cycling life of 5000 h comparing with bare Zn at 2 mA cm⁻² and 2 mA h cm⁻². Zn–I₂ full-cells can achieve 89 mA h g⁻¹ and 93% capacity retention after 20000 cycles.