Joint cationic and anionic redox chemistry in a vanadium oxide cathode for zinc batteries achieving high energy density
Wenfeng Wang, Lu Zhang, Zeang Duan, Ruyue Li, Jiajin Zhao, Longteng Tang, Yiming Sui, Yadi Qi, Shumin Han, Chong Fang, Desong Wang, Xiulei Ji
Abstract
Abstract Rechargeable 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 V 5+ /V 3+ accompanied by the Zn 2+ storage and the anionic O – /O 2– 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 Zn 2+ and anions as charge carriers.