Aluminium pre-intercalated orthorhombic V2O5 as high-performance cathode material for aqueous zinc-ion batteries

Abstract

Rechargeable aqueous zinc-ion batteries (AZIBs) are emerging as promising candidates for large-scale energy storage systems because of their low cost and high safety. However, the slow migration rate and strong electrostatic repulsion of divalent Zn2+ put forward many requirements for the properties of cathode materials. Herein, we present an aluminium pre-intercalated orthorhombic V2O5 (Al0.2V2O5) as a new cathode material for AZIBs. The analyses of GITT, ex-situ XRD, TEM and XPS indicate that the Al0.2V2O5 electrode possesses a higher Zn2+ diffusion coefficient than V2O5. And, the pre-intercalated Al3+ can stabilize the crystal structure and prevent Zn2+ from being trapped in the lattice. Because of the above advantages, Al0.2V2O5 shows much-enhanced electrochemical performance including a high capacity of 448.4 mA h g−1 at 0.1 A g−1, excellent rate capability of 143.9 mA h g−1 at 10 A g−1 and impressive long-term cycling stability with a capacity retention of 61.4% after 5000 cycles at 5 A g−1. Furthermore, the Al0.2V2O5/Zn battery can provide a high energy density of 327.1 W h kg−1 at 0.1 A g−1 and a high power density of 5491.8 W kg−1 at 10 A g−1, which shows great potential in the applications of large-scale energy storage.