Interface Engineering via the Use of Anion Additive Coupled with Dual Solvent for Aqueous Zinc Ion Batteries

In order to understand the anode‐electrolyte chemical interface, a dual salt‐dual solvent electrolyte was designed by including trace quantities of Cl − ions into the 1.5 M ZnSO 4 ‐H 2 O‐DEHMP electrolyte. Combination of experimental characterization techniques and theoretical calculations reveal that Cl − exhibits multifunctional electrolyte regulatory capabilities, including strong zincophilicity and reconfiguration of the hydrogen bond network in free water. Additionally, the chloride anions modify the charge transfer kinetics by reducing the high charge impedance in the electrolyte containing only DEHMP, hence facilitating optimal ionic conductivity for the Cl − and DEHMP electrolyte system. Meanwhile, the DEHMP significantly modifies the solvation shell and produces solid electrolyte interface layer advantageous for stabilizing the Zn anodes. Through the synergistic effect of Cl − anions and DEHMP, both parasitic reactions and dendrites growth are significantly diminished. Consequently, the Zn||Zn symmetric cell exhibited improved stability and reversibility over 1965 h at current density of 0.5 mA cm −2 and areal capacity of 0.5 mAh cm −2 . Meanwhile, the Zn||PANI full cell shows excellent stability in the hybrid electrolyte at 0.5 A g −1 .