Structural characteristic of vanadium(V) oxide/sulfur composite cathode for magnesium battery applications

Magnesium batteries are regarded as promising candidates for energy storage devices owing to their high volumetric capacity. The practical application is hindered, however, by strong electrostatic interactions between Mg²⁺ and the host lattice and due to the formation of a passivation layer between anode and electrolyte. V₂O₅ is a typical intercalation compound with a layered crystal structure ((0 0 1) interlayer spacing ~ 11.53 Å), which can act as a good host for the reversible insertion and extraction of multivalent cations. Herein, we have presented an investigation of the effects of S injection on the structure, electrochemical performance and Mg²⁺ diffusion in V₂O₅ cathode materials for Mg-ion batteries. The V₂O₅/S composite structure was investigated using X-ray diffraction, field-emission scanning electron microscope and energy dispersive X-ray spectroscopy. The integrated electrode exhibits an improvement in the electrical and electrochemical properties compared to the V₂O₅ electrode. The as-prepared V₂O₅/S composite has an initial discharge capacity of 310 mAh g⁻¹ compared to 160 mAh g⁻¹ for the V₂O₅ electrode. The V₂O₅/S composite is a promising cathode material for magnesium-ion battery applications.