Synergetic Structural Optimizations of Zinc Anodes and Electrolytes to Enable Zinc-Iodine Batteries with Excellent...

Challenges like zinc dendrite growth, hydrogen evolution, and electrolyte freezing hinder the development of aqueous Zn-based batteries. To address these issues, we implemented synergetic structural optimizations. A stress-mediated (002)-textured Zn anode was fabricated and characterized via cross-sectional electron channeling contrast. Additionally, ethylene glycol was used to further promote planar Zn electrodeposition via regulation of its kinetics, with Zn crystal nucleation observed. Interestingly, low concentrations of I^- ions were incorporated into the ZnSO₄ electrolyte and formed a hydrophobic inner Helmholtz plane on the Zn anode, effectively suppressing hydrogen evolution. As a result, the modified Zn symmetric battery achieved an impressive 7710 h of stable cycling at 5 mA cm^-2/1 mAh cm^-2 and 1800 h at 12 mA cm^-2/6 mAh cm^-2. Furthermore, the modified Zn-I₂ battery demonstrated an outstanding low-temperature performance, delivering a discharge capacity of 89 mAh g^-1 at 0.2 A g^-1 after 2300 cycles at -30 °C.