Flexible High-Energy and Stable Rechargeable Vanadium-Zinc Battery Based on Oxygen Defect Modulated V2O5 Cathode

Abstract The development of earth-abundant, high-capacity and stable cathode materials for robust aqueous Zn-ion batteries (ZIBs) is an ongoing challenge. With the merits of suitable operating voltage window and highly reversible redox reaction, vanadium oxide has recently emerged as an attractive cathode material. Herein, an oxygen defect modulated binder-free V2O5 nanorods (named as PVO@C) was constructed for aqueous/quasi-solid-state Zn ion battery. Accompanying the fast electron transport ability, increased concentration of oxygen defect and enhanced active sites, the aqueous PVO@C//Zn battery delivers an excellent high capacity of 385.34 mAh g−1 at 0.13 A g−1 and robust long-term life span of 86.7% capacity retention after 5000 cycles with nearly 100% coulomb efficiency. In particular, the assembled quasi-solid-state ZIBs exhibited the high voltage of 1.3 V, yielding an admirable energy density of 10.5 mWh cm−3 at a power density of 33.4 mW cm−3 and admirable cycling performance. What’s more, the solid-state ZIB exhibits extremely high safety, wettability and wear-ability over the lithium ion batteries. It performs well even at a variety of severe hazardous conditions, such as punctured, soaked, bent, sewed, washed, cut, and hammered conditions. This work innovatively proposes the synergistic effect of oxygen defect modulation and phosphorus doping to optimize reaction kinetics, which will lead to further improvements in the performance of metal oxides electrode. This strategy can be extended to electrode materials of other battery systems for the construction of highly efficient flexible energy storage devices and accelerated the commercialization of wearable electronics technology.