Antisolvent Regulation of Interfacial Chemistry for Aqueous Zn||LiFePO 4 Hybrid‐Ion Batteries With High Areal Capacity and Low Self‐Discharge

ABSTRACT Aqueous Zn/Li hybrid‐ion batteries are promising for grid‐scale energy storage owing to intrinsic safety and cost‐effectiveness, yet practical application is plagued by severe interfacial issues such as Zn dendrite growth, hydrogen evolution and transition metal dissolution, particularly under high cathode loading and lean electrolyte conditions. Herein, we propose a diethylene glycol (DEG)‐modified Li 2 SO 4– ZnSO 4 electrolyte to stabilize Zn 2+ /Li + dual‐cation chemistry. As a molecular modulator, DEG reorganizes hydrogen‐bonding networks and reconstructs cation solvation sheaths, efficiently suppressing parasitic water activity. At the anode, DEG preferentially adsorbs to build a dynamic shielding layer, inducing uniform Zn (002) deposition and alleviating corrosion. Meanwhile, it stabilizes the lithium iron phosphate (LiFePO 4 , LFP) cathode by accelerating Li + transport kinetics and restraining Fe dissolution. The assembled Zn||LFP full cell with 15 mg cm −2 cathode loading and an N/P ratio of 2.37 delivers 2.64 mAh cm −2 and retains stable cycling over 1700 times at 5 mA cm −2 , also achieving ultralow self‐discharge and excellent sub‐zero tolerance. This antisolvent engineering strategy offers a scalable route toward high‐energy‐density and commercially viable aqueous hybrid‐ion batteries.