Sol–gel synthesis of Mg1.03Mn0.97SiO4 and its electrochemical intercalation behavior

Magnesium manganese silicate (Mg1.03Mn0.97SiO4) was prepared by a sol–gel method and evaluated as an intercalation electrode material for rechargeable magnesium batteries. The crystalline Mg1.03Mn0.97SiO4 phase was obtained after heating at 900 °C and its electrochemical performance was characterized at room temperature. The pure magnesium manganese silicate exhibits a relatively low reversible specific capacity in the electrolyte comprising 0.25 mol L−1 Mg(AlCl2EtBu)2/THF owing to its poor electronic conductivity. Using a ball mill in the presence of acetylene black, and in situ carbon coating, the resulting composites present an improved discharge voltage plateau (1.6 V vs. Mg/Mg2+) and increased discharge specific capacity (92.9 mAh g−1 at a C/50 rate). The Mg lower price and its feasibility for rechargeable batteries make magnesium manganese silicate an attractive candidate for rechargeable magnesium based batteries.