Synthesis of polycrystalline K0.25V2O5 nanoparticles as cathode for aqueous zinc-ion battery

Polycrystalline K0.25V2O5 nanoparticles have been synthesized and evaluated as cathode for aqueous zinc-ion batteries, which demonstrates excellent Zn2+ storage capability. As elucidated, a high capacity of 306 mA h g−1, excellent rate capability of 5 A g−1 and long-term cyclic stability up to 500 cycles at 2 A g−1 are achieved. The effect of the K+ ions and the role of morphology for K0.25V2O5 cathode were also discussed in this work. CV measurements at different rates demonstrate that partial surface-controlled capacitive behavior contributes to the capacity of polycrystalline K0.25V2O5 nanoparticles. The zinc storage mechanism is investigated, which demonstrates as a highly reversible intercalation-type cathode for K0.25V2O5 with unique three-dimensional tunnel structure.