Improved lithium storage properties of Mg2Si anode material synthesized by hydrogen-driven chemical reaction

Nanocrystalline Mg2Si with high purity, homogeneous composition and uniform particle size was successfully synthesized by a facile hydrogen-driven chemical reaction at below 500 °C. The as-prepared Mg2Si exhibited an improved Li-ion storage ability as anode material for Li-ion batteries as it delivered an initial capacity of about 1095 mAh/g at 100 mA/g. The discharge capacity stayed at 406 mAh/g after 60 cycles, which is much better than that of the commercial Mg2Si anode and previously reported Mg2Si anode synthesized by mechanical alloying. The proof-of-concept synthesis technique presented in this work should be valuable for the preparation of other intermetallic compounds with difference of melting point between the constituent elements.

► Nanocrystalline Mg2Si was synthesized via a facile hydrogen-driven reaction.
► The as-prepared Mg2Si exhibits a significantly improved Li-ion storage ability.
► The as-prepared Mg2Si delivers an initial discharge capacity of 1095 mAh/g.
► The first Coulombic efficiency is about 92%.
► More than 37% of the reversible capacity is retained after 60 cycles.