Electroactivation-induced spinel ZnV2O4 as a high-performance cathode material for aqueous zinc-ion battery

Rechargeable and affordable aqueous zinc-ion batteries (ZIBs) with high energy density are needed for large-scale energy storage systems. However, the development of ZIBs has stagnated due to the lack of stable high-capacity cathode materials. Here, a typical spinet ZnV2O4 has been investigated as a ZIB cathode, and a significant electroactivation reaction was observed during the initial electrochemical cycles. After electroactivation, ZnV2O4 exhibits a high reversible capacity of 312 mAh g(-1) and retains a capacity of 206 mAh g(-1) over 1000 cycles at a high rate of 10 C. The electroactivation process was then analyzed via in-situ XRD, ex-situ PDF, ex-situ HADDF-STEM, ex-situ XPS, and various electrochemical measurements. The electroactivation enhances the surface electrochemical reaction with self-adaptive adjustment of the lattice structure. This guarantees outstanding electrochemical performance. The encouraging results deepen our understanding of rechargeable aqueous batteries and offer insight into the design of high-performance electrode materials for rechargeable aqueous ZIBs.