Simultaneous Cationic and Anionic Redox Reactions Mechanism Enabling High‐Rate Long‐Life Aqueous Zinc‐Ion Battery

Abstract Rechargeable aqueous zinc‐ion batteries hold great promise for potential applications in large‐scale energy storage, but the reversible insertion of bivalent Zn 2+ and fast reaction kinetics remain elusive goals. Hence, a highly reversible Zn/VN x O y battery is developed, which combines the insertion/extraction reaction and pseudo‐capacitance‐liked surface redox reaction mechanism. The energy storage is induced by a simultaneous reversible cationic (V 3+ ↔ V 2+ ) and anionic (N 3− ↔ N 2− ) redox reaction, which are mainly responsible for the high reversibility and no structural degradation of VN x O y . As expected, a superior rate capability of 200 mA h g −1 at 30 A g −1 and high cycling stability up to 2000 cycles are achieved. This finding opens new opportunities for the design of high‐performance cathodes with fast Zn 2+ reaction kinetics for advanced aqueous zinc‐ion batteries.