Calcium ion modified layered vanadium dioxide composite as advanced cathode material with high capacity and stability in aqueous zinc ion battery

Rechargeable aqueous zinc-ion batteries (AZIBs), characterized by affordability, simplicity, safety, and environmental friendliness, are poised to emerge as a viable alternative to lithium-ion batteries in energy storage applications. However, conventional cathodes have thus far impeded the large-scale application of AZIBs due to the limitations in transport kinetics and structural instability. Layered vanadium oxide cathodes show potential as cathode materials, primarily due to open layered structure and adjustable chemical composition. Despite these structural advantages, the material is susceptible to dissolution and collapse during charging and discharging processes, ultimately resulting in rapid capacity degradation and compromised cyclability. Herein, a series of Ca 2+ ions pre-inserted VO 2 ·xH 2 O@C nanoribbons are prepared using an optimized pre-embedding strategy. The irreversible structural transformation from Ca-VO 2 ·xH 2 O@C to Ca-V 2 O 5 ·xH 2 O@C phase optimizing the electrochemical performance of the cathode in Zn 2+ storage. The synergistic effect between Ca 2+ and lattice water not only enhances the Zn 2+ storage capacity but also effectively stabilizes the nanostructure, where Ca 2+ ions function as interlayer “pillars” to prevent structural collapse during prolonged cycling processes. As such, the Ca-VO 2 ·xH 2 O@C-2 cathode shows a high capacity of 519 mA h g −1 at 0.1 A g −1 , and still maintain a capacity of 267 mA h g −1 after 3000 cycles at 10 A g −1 . This work provides a high-performance cathode material in AZIBs that is expected to possess promising applications in future energy storage systems. • A calcium-ion pre-intercalated hydrated vanadium dioxide composite was synthesized via a simple one-step hydrothermal method. • The cooperative effect of calcium ions and water molecules accelerates zinc ion insertion and extraction. • The CaVOH@C cathode delivers a high initial capacity of 519 mA h g −1 at 0.1 Ag −1 . • The CaVOH@C cathode exhibits a stable cycling life of 3000 cycles at 10 A g -1 .