Affiliation:
1. Hebei Key Laboratory of Applied Chemistry, State Key Laboratory of Metastable Materials Science and Technology Yanshan University Qinhuangdao China
2. Department of Chemistry Oregon State University Corvallis Oregon USA
Abstract
AbstractRechargeable aqueous zinc batteries are promising for large‐scale energy storage due to their low cost and high safety; however, their energy density has reached the ceiling based on conventional cathodes with a single cationic redox reaction mechanism. Herein, a highly reversible cathode of typical layered vanadium oxide is reported, which operates on both the cationic redox couple of V5+/V3+ accompanied by the Zn2+ storage and the anionic O–/O2– redox couple by anion hosting in an aqueous deep eutectic solvent electrolyte. The reversible oxygen redox delivers an additional capacity of ∼100 mAh g–1 at an operating voltage of ∼1.80 V, which increases the energy density of the cathode by ∼36%, endowing the cathode system a record high energy density of ∼506 Wh kg–1. The findings highlight new opportunities for the design of high‐energy zinc batteries with both Zn2+ and anions as charge carriers.