Highly Reversible Phase Transition Endows V 6 O 13 with Enhanced Performance as Aqueous Zinc‐Ion Battery Cathode

Aqueous zinc‐ion batteries (ZIBs), with favorable merits of high security and low cost, have gained much interest in the energy storage field. However, their development is still in its infancy. Herein, V 6 O 13 is investigated as aqueous ZIB cathodes with excellent Zn 2+ storage performance, as compared with VO 2 and V 2 O 5 . The intrinsic open structure of V 6 O 13 with mixed‐valance states of vanadium (V 4+ /V 5+ ) is favorable to enable fast Zn 2+ ion diffusion and improved electronic conductivity, outperforming VO 2 and V 2 O 5 . Significantly, the highly reversible phase transition of zinc vanadate (Zn 0.25 V 2 O 5 ·H 2 O) can be detected during discharging, which enables the insertion of more Zn 2+ ions into the host structure. As a result, V 6 O 13 can exhibit enhanced electrochemical properties, including high capacity and excellent long‐term cyclability (206 mA h g −1 at 10 A g −1 after 3000 cycles).