Manganese ion pre-intercalated hydrated vanadium oxide as a high-performance cathode for magnesium ion batteries

The development of rechargeable magnesium ion batteries (MIBs) has received increasing attention due to its low cost, high theoretical volumetric capacities, environmental friendliness and good safety. However, one of the main challenges faced by MIBs is the difficulty in finding a suitable electrode material due to the sluggish kinetics of the magnesium ion. Herein, we report a manganese ion pre-intercalated hydrated vanadium oxide (Mn0.04V2O5 center dot 1.17H(2)O) as the cathode material for MIBs for the first time. Pre-intercalation of Mn2+ leads to excellent structural stability and allows fast (de) insertion of Mg2+ ions. The charge shielding effect of crystal water in the material enhances the Mg2+ (de) insertion kinetics and the unique nanostructure ensures the large contact area and shortens the Mg2+ diffusion distance between the electrode and electrolyte. Benefiting from the structure and charge shielding effect, the Mn0.04V2O5 center dot 1.17H(2)O nanobelts exhibit excellent cycling stability (capacity retention of 82% after 10 000 cycles at 2 A g(-1)) and superior rate performance. These results indicate that Mn0.04V2O5 center dot 1.17H(2)O is a promising and attractive cathode material for MIBs.