A stable "rocking-chair" zinc-ion battery boosted by low-strain Zn3V4(PO4)6 cathode

Aqueous zinc metal batteries benefit from the high volumetric energy density and rich abundance of zinc metal, but suffer from the uncontrollable dendrites, passivation and corrosion which severely hinder their development. Developing Zn-containing cathodes to couple with Zn-free anodes is an effect approach to overcome the above challenges, however, such robust hosts that can afford reversible and stable Zn2+ storage have been rarely reported. Herein, we reported a novel low-strain Zn3V4(PO4)6 cathode for zinc-ion battery which delivers a specific capacity of 105.2 mAh g−1, outstanding cycling stability (100 % capacity retention over 250 cycles) and superior rate capability (62.9 mAh g−1 at 40 C). Both density functional theory (DFT) calculation and in-situ characterization reveals the small volume change (2.4 %) of Zn3V4(PO4)6 upon Zn2+ storage. Note that a "rocking-chair" zinc-ion battery is established based on the Zn3V4(PO4)6 cathode and layered TiS2 anode, which demonstrates remarkable electrochemical reversibility and favorable cycling stability.