Mixed valence V 2 O 5 induced by K + enable ultra-long cycling life for aqueous zinc ion batteries

Identifying new cathode materials with excellent properties is crucial for improving the overall energy-storage performance of aqueous zinc-ion batteries (AZIBs). Vanadium-based materials with superior theoretical specific capacities are the main candidates for cathode materials in AZIBs; however, their slow kinetics and poor stability limit their application. Hence, we prepared K0.19V2O5·0.68H2O (KVOH) nanorods with mixed valence states by pre-inserting K+ into V2O5 to enhance the structural stability and electrical conductivity. The K+ in the interlayer altered the electronic structure and formed stable K-O bonds, constructing a 3D electron conduction network. Oxygen vacancies provided extra active sites for Zn2+, increased the surface reactivity to enhance Zn2+ storage capacity, and inhibited the dissolution of the electrode material in the electrolyte. The specific capacity of the KVOH cathode reached 479.4 mAh g-1 at 0.1 A g-1, with a 92.5% capacity retention after 10,000 cycles at 8 A g-1. Overall, this study provides a general strategy for designing and integrating cathode materials that achieve both high capacity and high-rate performance, paving the way for advancements in the field of AZIBs. .