In-situ prepared of quadrilateral flake Zn0.25(NH4)V2O5·H2O as a cathode for aqueous rechargeable Zn-ion batteries

Abstract

Aqueous zinc ion batteries (AZIBs) have great potential in the large-scale energy storage as its low price, safety, efficiency and environmental friendliness. In this work, a novel cathode of quadrilateral flake Zn0.25(NH4)V2O5·H2O is prepared in-situ by electrochemical induction, in which NH4+ and hydrated zinc ions are co-embedded in VO framework. Specifically, the Zn0.25(NH4)V2O5·H2O electrode displays a largest discharge specific capacity of 355 mA h g−1 at 0.1 A g−1 in 2 M Zn (CF3SO3)2, and shows an excellent cycle lifespan of 84.6% capacity retention at 1 A g−1. Furthermore, the Zn//Zn0.25(NH4)V2O5·H2O cell is evaluated its practicability by driving a motor fan. In addition, we adopt ex-situ XRD and XPS to investigate the electrochemical induction process and energy storage mechanism of the Zn0.25(NH4)V2O5·H2O electrode, and Zn0.25(NH4)V2O5·H2O electrode follows a typical reversible zinc ion intercalation/deintercalation mechanism. Finally, this electrochemical induction method will promote further in-depth research on vanadium-based material cathode for AZIBs.