Orientational Electrodeposition of Highly (002)-Textured Zinc Metal Anodes Enabled by Iodide Ions for Stable Aqueous Zinc Batteries

Abstract

Regulating the crystallographic texture of the zinc (Zn) metal anode is promising to promote Zn reversibility in aqueous electrolytes, but the direct fabrication of specific textured Zn still remains challenging. Herein, we report a facile iodide ion (I^-)-assisted electrodeposition strategy that can scalably fabricate highly (002) crystal plane-textured Zn metal anode (H-(002)-Zn). Theoretical and experimental characterizations demonstrate that the presence of I^- additives can significantly elevate the growth rate of the Zn (100) plane, homogenize the Zn nucleation, and promote the plating kinetics, thus enabling the uniform H-(002)-Zn electrodeposition. Taking the electrolytic cell with the conventional ZnSO₄-based electrolyte and commercial Cu substrate as a model system, the Zn texture gradually transforms from (101) to (002) as the increase of NaI additive concentration. In the optimized 1 M ZnSO₄ + 0.8 M NaI electrolyte, the as-prepared H-(002)-Zn features a compact structure and an ultrahigh intensity ratio of (002) to (101) signal without containing the (100) signal. The free-standing H-(002)-Zn electrode manifests stronger resistance to interfacial side reactions than the conventional (101)-textured Zn electrode, thus delivering a high efficiency of 99.88% over 400 cycles and ultralong cycling lifespan over 6700 h (>9 months at 1 mA cm^-2) and assuring the stable operation of full Zn batteries. This work will enlighten the efficient electrosynthesis of high-performance Zn anodes for practical aqueous Zn batteries.