Green synthesis of Co₃O₄/graphene nanocomposite as cathode for magnesium batteries

Ultrafine Co₃O₄ nanoparticles homogeneously attached to graphene sheets by sonochemical method have been demonstrated as a promising cathode material for magnesium batteries. X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) have been employed to characterize the structural properties of this material. SEM analyses clearly confirmed that the Co₃O₄ nanoparticles have been uniformly coated on the entire surface of graphene sheets to form a compact composite. The Co₃O₄-graphene nanocomposite was employed as a cathode electrode in magnesium-ion batteries, and their electrochemical properties were briefly investigated. The graphene sheets can also effectively buffer the volume change in Co₃O₄ upon magnesium insertion/extraction, thus improving the cycling preformance of the composite electrode. It was revealed that the Co₃O₄-graphene composite can provide a small capacity of 16 mAh·g^-1 using a new nonaqueous electrolyte that is tetrahydrofuran-free, which provides a new direction to explore cathode materials for Mg batteries.