In-Situ Lattice Tunnel Intercalation of Vanadium Pentoxide for Improving Long-Term Performance of Rechargeable Magnesium Batteries

Layered V2O5 is a promising and versatile cathode for rechargeable magnesium batteries (RMBs), but its narrow interlayer spacing makes rapid Mg2+ diffusion difficult, resulting in poor electrochemical performance. Herein, a facile and scalable technique is established for tailoring the (001) spacing of V2O5 by in-situ polyaniline polymerization. The intercalated polyaniline molecules operate as pillars in the V2O5 interlayer, providing plentiful storage sites as well as improved cation diffusivities of Mg ion. As expected, by using V2O5/polyaniline as the cathode (anode: Mg metal), a high specific capacity of 361 mAh g(-1) with charging/discharging current density of 20 mA g(-1) can be achieved for RMBs. Besides, V2O5/polyaniline electrode shows favorable rate capability with 103 mAh g(-1) at 500 mA g(-1) (500 cycles) and ultra long-term cycling performance after 5000 cycles. Ex situ X-ray photoelectron spectroscopy is used to study the magnesium storage mechanism of the V2O5/polyaniline electrode.

Automated summary

A facile and scalable technique for tailoring the (001) spacing of V2O5 by in-situ polyaniline polymerization is established, yielding a porous V2O5/polyaniline composite as the anode for rechargeable magnesium batteries. The composite material, with increased interlayer spacing and improved ion diffusion, demonstrates outstanding electrochemical performance and long-term cycling stability.