In-situ Constructing Hydrophobic Channel Interconnecting Progressively Zincophilic Planes on Zn Surface for Stable Zn Metal Anode

Abstract

The poor reversibility of Zn stripping/plating processes induces the unsatisfactory cycling stability of Zn anode and limits the practical application of aqueous zinc ion batteries. Herein, sulfobutylether-β-cyclodextrin (SCD) was introduced in the electrolyte as a multi-functional additive. The zincophilic sulfonate groups can interact with Zn²⁺ to modulate the solvation structure, strengthen the adsorption and govern the adsorption configuration of SCD on Zn surface. This specific adsorption configuration can in-situ construct two planes on Zn surface with progressively improved affinity to Zn²⁺, which can drive the diffusion of Zn²⁺ through the hydrophobic toroidal inner channel and realize the uniform dispersion of Zn²⁺ flux and facilitate the de-solvation process. The synergistically promotional effect of the functional groups and specific structure features remarkably improve the stability of Zn anode. With the addition of SCD, the Zn//Cu cell exhibited a long cycle life of over 3000 cycles with the average CE of over 99.7%. The Zn//Zn symmetric cell also provides the superior cycling stability of over 3900 h at 2 mA cm^-2. The corresponding Zn//NH₄V₄O₁₀ full cells deliver higher specific capacity and better cycling stability than the cells using bare electrolytes, and the assembled pouch cells are also stable for over 300 cycles, demonstrating the practical application potential of this electrolyte in high-performance AZIBs.