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

摘要

Rechargeable aqueous zinc-ion batteries hold great promise for potential applications in large-scale energy storage, but the reversible insertion of bivalent Zn2+ and fast reaction kinetics remain elusive goals. Hence, a highly reversible Zn/VNxOy 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 (V3+ V2+) and anionic (N3- N2-) redox reaction, which are mainly responsible for the high reversibility and no structural degradation of VNxOy. 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 Zn2+ reaction kinetics for advanced aqueous zinc-ion batteries.