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_0.3V₂O₅ 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 Zn²⁺ 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.