Interfacial Engineering of Amorphous TiO2 Coatings for Dendrite-Free and Highly Reversible Zinc Metal Anodes.

Abstract

The commercialization of aqueous zinc-ion batteries (AZIBs) is limited by uncontrollable dendrite growth and interfacial side reactions. To tackle this critical issue, we propose a surface engineering strategy involving the deposition of a zincophilic amorphous titanium dioxide (AS-TiO₂) protective layer onto the zinc anode. The resulting Zn@AS-TiO₂ anode demonstrates remarkable electrochemical performance, achieving exceptional cycling stability over 3750 h at 1 mA cm^-2 while maintaining near-ideal Coulombic efficiency (99.5%) and outstanding deposition/stripping reversibility. Mechanistic studies reveal that the enhanced performance primarily stems from the significantly higher binding energy of Zn adsorption on amorphous TiO₂ compared to those on crystalline TiO₂ and bare Zn, which endows the Zn@AS-TiO₂ anode with superior zincophilicity and substantially reduces the Zn²⁺ nucleation overpotential. In addition, the amorphous structure facilitates a more homogeneous electric field distribution at the electrode-electrolyte interface, effectively regulating Zn²⁺ flux and promoting uniform Zn deposition. As a result, dendrite formation is efficiently suppressed even during prolonged cycling. This interface modification strategy, which integrates zincophilic surface engineering with electric field regulation, offers valuable mechanistic insights into dendrite suppression and presents a promising pathway for the development of durable metal anodes in next-generation aqueous energy storage systems.