Modified vanadium oxide with enhanced diffusion kinetic for high rate aqueous zinc-ion batteries

At present, research on aqueous ion batteries is progressing rapidly and vanadium oxide with fast and stable Zn2+ storage performance has aroused widespread interest in the development of high-performance aqueous zinc-ion batteries (AZIBs). However, it generally has the problems of structural collapse and slow diffusion kinetics, which hinder its promising large-scale application. Herein, a cathode material of self-assembled nanospheres of V2O5 modified with K-ion (KVO) was reported by one-pot hydrothermal method. The introduction of K+ not only considerably improves the conductivity of vanadium oxide, which further enhances the diffusion kinetics of Zn2+, but also successfully increases the interlayer spacing. Hence, the assembled Zn-ion batteries based on KVO cathode demonstrated outstanding rate performance and strong cycle stability with a high discharge capacity of 226 mAh g−1 at 10 A g−1 and a capacity retention rate of 66.9 % after 9000 cycles at the same current density. It also exhibited a high energy density of 262 Wh kg−1 at 1 A g−1. Finally, flexible quasi-solid ZIBs were assembled utilizing KVO as cathode and demonstrated their good Zn2+ storage properties and promising application prospects. This work may provide a direction for designing or developing other layered transition metal oxides cathode for AZIBs.