K-ion modified V2O5 with abundant oxygen defects as cathode for aqueous zinc-ion battery

Aqueous zinc-ion batteries (ZIBs) are anticipated to be used for grid-scale energy storage because of their low cost, abundant resources, high safety, and non-toxicity. In this study, K-ion modified V2O5 with abundant oxygen defects (K0.1V2O5) was prepared using a one-step hydrothermal reaction followed by heat treatment. K0.1V2O5 showed remarkable specific capacity (307.9 mAhg−1 at 0.2 Ag−1), exceptional rate capability (184.3 mAhg−1 at 10 Ag−1), and good cycling stability (88.5 % capacity retention rate after 2000 cycles at 10 Ag−1). Furthermore, electrochemical kinetics revealed that the electrochemical process of the K0.1V2O5 electrode is governed by both ion diffusion and capacitive contribution, with the diffusion coefficient of Zn2+ ranging between 10−11 and 10−9 cm2 s−1. The exceptional performance of K0.1V2O5 makes it a promising candidate for cathode materials in zinc-ion batteries (ZIBs).