Cs‐Induced Phase Transformation of Vanadium Oxide for High‐Performance Zinc‐Ion Batteries

Rechargeable aqueous zinc‐ion batteries are promising candidate for grid‐scale energy storage. However, the development of zinc‐ion batteries has been plagued by the lack of cathode materials with high specific capacity and superior lifespan. Herein, hexagonal Cs 0.3 V 2 O 5 cathode is fabricated and investigated in zinc‐ion batteries. Compared with the traditional vanadium oxides, the introduction of Cs changes the periodic atomic arrangements, which not only stabilizes the open framework structure but also facilitates the Zn 2+ diffusion with a lower migration energy barrier. Consequently, high specific capacity of 543.8 mA h g −1 at 0.1 A g −1 is achieved, which surpasses most of reported cathode materials in zinc‐ion batteries. The excellent cycle life is achieved over 1000 cycles with about 87.8% capacity retention at 2 A g −1 . Furthermore, the morphological evolution and energy storage mechanisms are also revealed via a series of techniques. This work opens up a phase engineering strategy to fabricate the hexagonal vanadium oxide and elucidate the application of phase‐dependent cathodes in zinc‐ion batteries.