Bidentate Coordination Enables Anions‐Regulated Solvation Structure for Advanced Aqueous Zinc Metal Batteries

Abstract Rechargeable aqueous Zn metal batteries (AZMBs) are attractive for stationary energy storage due to their low cost and high safety. However, their practical application is hindered by the excessive use of zinc anodes and poor high‐temperature performance, caused by severe side reactions and dendritic growth issues. Here, an electrolyte design strategy is reported based on bidentate coordination of Zn 2+ and solvent to tailor the solvation structure. The triethylene glycol (TEG) co‐solvent with two‐oxygen coordination sites is demonstrated to facilitate the formation of an anions‐involved solvation shell, greatly reducing the activity of coordinated H 2 O molecules. The sequential reduction of OTF − anions and TEG leads to the formation of an organic–inorganic bilayer SEI (hydrophobic organic layer and high ion conductivity inorganic layer), protecting Zn anodes from side reactions and dendrite growth, thus ensuring an unprecedented Zn reversibility (99.95 % over 5000 cycles at 0.5 mA cm −2 ). More importantly, the full cells of Zn||V 2 O 5 exhibit a record‐high cumulative capacity (2552 mAh cm −2 ) under a lean electrolyte condition (E/C ratio=15 μl mAh −1 ), a limited Zn supply (N/P ratio=1.9) and a high areal capacity (3.0 mAh cm −2 ).