Dual-engineering of VOOH for enhanced phase transition kinetics and stability in aqueous zinc ion batteries

Low-valence vanadium cathode materials provide excellent electrochemical performance for aqueous zinc-ion batteries (AZIBs) after in-situ oxidative phase transition. However, these materials generally suffer from slow phase transformation rates and poor cycle stability, which limit their potential and efficiency in large-scale energy storage applications. Herein, we report a dual-engineering technique contained oxygen vacancies and amorphous mesoporous structures to boost the performance of VOOH. This strategy effectively modulates the electronic structure in V-based cathode materials and increases their reactivity with the electrolyte, resulting in a nearly 2.4-fold improvement in the phase transition efficiency compared to VOOH without dual characteristics. The transition to ZVO maintains the doping of S elements and introduces interlayer Zn 2+ ions, which facilitate enhanced charge transfer and contribute to the stability of the cathode structure. The assembled AZIBs display superior rate capability (567 and 397 mAh g −1 at 0.1 and 5 A g −1 , respectively) and have an ultra-long cycle life (92% capacity retention over 2000 cycles at 5 A g −1 ). Additionally, the underlying electrochemical reaction mechanisms and determinant factors of the conversion processes have been meticulously investigated through ex-situ characterizations. This work provides new insights into the development of high-performance vanadium oxide-based cathodes for AZIBs.