Concentrated perchlorate‐based electrolyte facilitates Zn anode‐compatible in situ solid electrolyte interphase

Abstract Zinc perchlorate (Zn(ClO 4 ) 2 ) electrolytes have demonstrated favorable low‐temperature performance in aqueous zinc‐ion batteries (AZIBs). However, the Zn anode encounters serious dendrite formation and parasitic reactions in zinc perchlorate electrolytes, which is caused by the fast corrosive kinetics at room temperature. Herein, a concentrated perchlorate‐based electrolyte consisting of 4.0 M Zn(ClO 4 ) 2 and saturated NaClO 4 solution is developed to achieve dendrite‐free and stable AZIBs at room temperature. The ClO 4 − participates in the primary solvation sheath of Zn 2+ , facilitating the in situ formation of Zn 5 (OH) 8 Cl 2 ·H 2 O‐rich solid electrolyte interphase (SEI) to suppress the corrosion effect of ClO 4 − . The Zn anode protected by the SEI achieves stable Zn plating/stripping over 3000 h. Furthermore, the MnO 2 ||Zn full cells manifest a stable specific capacity of 200 mAh·g −1 at 28 °C and 101 mAh·g −1 at − 20 °C. This work introduces a promising approach for boosting the room‐temperature performance of perchlorate‐based electrolytes for AZIBs.