Anion Additive Integrated Electric Double Layer and Solvation Shell for Aqueous Zinc Ion Battery

Abstract Aqueous zinc ion batteries (AZIBs) show great potential in large‐scale energy storage systems. However, the inferior cycling life due to water‐induced parasitic reactions and uncontrollable dendrites growth impede their application. Electrolyte optimization via the use of additives is a promising strategy to enhance the stability of AZIBs. Nevertheless, the mechanism of optimal multifunctional additive strategy requires further exploration. Herein, sodium dodecyl benzene sulfonate (SDBS) is proposed as a dual‐functional additive in ZnSO4 electrolyte. Benefiting from the additive, both side reactions and zinc dendrites growth are significantly inhibited. Further, a synchrotron radiational spectroscopic study is employed to investigate SDB− adjusted electric double layer (EDL) near the Zn surface and the optimized solvation sheath of Zn2+. First‐principles calculations verify the firm adsorption of SDB−, and restriction of random diffusion of Zn2+ on the Zn surface. In particular, the SDBS additive endows Zn||Zn symmetric cells with a 1035 h ultra‐stable plating/stripping at 0.2 mA cm−2. This work not only provides a promising design strategy by dual‐functional electrolyte additives for high stable AZIBs, but also exhibits the prospect of synchrotron radiation spectroscopy analysis on surface EDL and Zn2+ solvation shell optimization.