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

Zinc perchlorate (Zn(ClO₄)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(ClO₄)₂ and saturated NaClO₄ solution is developed to achieve dendrite-free and stable AZIBs at room temperature. The ClO₄⁻ participates in the primary solvation sheath of Zn²⁺, facilitating the in situ formation of Zn₅(OH)₈Cl₂·H₂O-rich solid electrolyte interphase (SEI) to suppress the corrosion effect of ClO₄⁻. The Zn anode protected by the SEI achieves stable Zn plating/stripping over 3000 h. Furthermore, the MnO₂||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.