Favorable Desolvation and Uniform Zn Deposition of Silica Modified Zn Anode for High Performance Aqueous Zn-Ion Batteries

The instability of Zn anode resulting from corrosion and dendritic growth remain impeding the development of aqueous zinc-ion batteries (AZIBs). In addition, the desolvation on the Zn surface is sluggish, which hinders the reaction kinetics and fast charge/discharge behavior of AZIBs. Herein, the uniform Zn deposition and fast desolvation are realized by using a hydrophilic fumed nano-silica coating with zinc alginate (Alg) as a functional binder (Alg/SiO₂@Zn). Combined theoretical calculation and experimental investigations show the interaction between the H₂O in the solvation structure and -OH functional group of SiO₂ facilitates the desolvation process. In addition to the Zn²⁺ guiding effect of Alg, the fast Zn²⁺ diffusion along SiO₂ endows the homogeneous Zn deposition. Consequently, Alg/SiO₂@Zn symmetric cell demonstrates exceptional plating/stripping reversibility and excellent long-term cycle life at both 1 and 10 mAh cm⁻². A full cell assembled with Alg/SiO₂@Zn and NaV₃O₈·xH₂O cathode achieves a high capacity of 129 mAh g⁻¹ at 4 A g⁻¹ over 2650 cycles. Even under −20 °C, the battery maintains a high capacity of 136.5 mAh g⁻¹ at 1 A g⁻¹ after 1000 stable cycles. This study provides a facile strategy to achieve a highly stable Zn anode and gains deep insight into desolvation modulation via surface modification.