Architecting a Hydrated Ca 0.24 V 2 O 5 Cathode with a Facile Desolvation Interface for Superior-Performance Aqueous Zinc Ion Batteries.

Vanadium-based materials are promising cathode candidates for low-cost and high-safety aqueous zinc-ion batteries (AZIBs). However, they suffer from inferior rate capability and undesirable capacity fading due to their intrinsic poor conductivity and structural instability. Herein, we synthesize hydrated Ca 0.24 V 2 O 5 ·0.75H 2 O (CaVOH) nanoribbons with in situ incorporations of the carbon nanotubes via a one-step hydrothermal method, achieving an integrated architecture hybrid cathode (C/CaVOH) design. Benefitting from the robust structure and low desolvation interface, the prefabricated C/CaVOH cathodes deliver a high capacity of 384.2 mA h g -1 at 0.5 A g -1 with only 5.6% capacity decay over 300 cycles, enable an ultralong cycling life of 10,000 cycles at 20.0 A g -1 with 80.2% capacity retention, and exhibit an impressive rate capability (165 mA h g -1 at 40.0 A g -1 ) with a high mass loading of ∼4 mg cm -2 . Moreover, through the theoretical calculations and a series of ex situ characterizations, we demonstrate the Zn 2+ /H + co-intercalation storage mechanism, the key role of the gallery water, and the function of the induced C-O groups in promoting kinetics of the C/CaVOH electrode. This work highlights the strategy of in situ implanted high conductivity materials to engineer vanadium-based or other cathodes for high-performance AZIBs.