Mg2+ pre-intercalated hydrated vanadium oxide as high-performance cathode for aqueous zinc-ion batteries

Abstract

Aqueous zinc-ion batteries (ZIBs) have shown great potential in large-scale energy storage systems due to their economic efficiency and environmental friendliness. However, cathodes for aqueous ZIBs are affected by the slow Zn[Formula: see text] diffusion kinetics and limited capacity. Herein, Mg[Formula: see text]V2O[Formula: see text]H2O (MgVO) nanobelt cathode with a large interlayer spacing of 13.0 Å is prepared via a one-step hydrothermal approach. Furthermore, the pre-intercalated Mg[Formula: see text] can stabilize the crystal structure and prevent Zn[Formula: see text] from being trapped in the lattice. As a result, MgVO cathode delivers a high capacity of 386 mAh g[Formula: see text] at 0.1 A g[Formula: see text], and impressive long-term cycling stability with a capacity retention of 91% after 1500 cycles at 5 A g[Formula: see text]. Moreover, the Zn/[Formula: see text]/MgVO battery can provide a high-energy density of 269 W h kg[Formula: see text] at 0.1 A g[Formula: see text] and a high-power density of 2701 W kg[Formula: see text] at 5 A g[Formula: see text]. The simple preparation and low cost make this cathode show great potential in the applications of large-scale energy storage.