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 degrees 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 (1.6V 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. (C) 2008 Elsevier B.V. All rights reserved.