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.