Regulating oxygen vacancies in ammonium vanadate electrode materials for advanced aqueous zinc ion batteries

In the past decade, vanadates have attracted one's attention as the electrode materials for aqueous zinc ion batteries (AZIBs). Nevertheless, their structural instability and sluggish ion/electron dynamics lead to an inevitable decline in the electrochemical performance. To address these issues, we introduce oxygen vacancies into NH₄V₄O₁₀ nanosheets to improve the ion transport rate during the electrochemical reaction. The prepared NHVO-40 samples provide many active sites compared to NH₄V₄O₁₀ materials. The assembled cell delivers a capacity of 452.03 mAh g^-1 at a current density of 0.2 A g^-1. It also presents a retention rate of 94.6% at 10 A g^-1 after 4000 times cycling. In addition, they still possess an energy density of 332.5 Wh kg^-1 at a power density of 70 W kg^-1.