Mesoporous Magnesium Manganese Silicate as a Cathode Material for Rechargeable Magnesium Batteries

Mesoporous magnesium manganese silicate as a cathode material for rechargeable magnesium batteries was prepared using mesoporous silica MCM-41 as both template and silicon source. X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and N(2) adsorption-desorption measurements were performed to characterize the mesoporous structure of the as-prepared material. Furthermore, the electrochemical performance of mesoporous and bulk materials were compared by cyclic voltammetry and direct current charge-discharge measurements. The larger surface area of the mesoporous material favors the efficient contact between active material and electrolyte, providing more active sites for the electrochemical reaction. As a result, the mesoporous material exhibits better electrochemical performance with lower polarization for magnesium de-intercalation and intercalation, larger discharge capacity and higher discharge flat plateau compared with corresponding bulk material. In 0.25 mol/L Mg(AlCl(2)EtBu)(2)/THF electrolyte, the initial discharge capacity and discharge voltage plateau of the mesoporous material can reach 241.8 mAh/g and 1.65V, respectively. The mesoporous structure may provide a new approach to improve the reaction activity of the cathode materials for rechargeable magnesium batteries.