A metathesis reaction route to obtain fine Mg_2Si particles

摘要

We have developed a novel synthetic route for the production of fine Mg_2Si particles (＜1 μm) using NaSi, MgCl_2, and Na. Mg_2Si was suggested to be formed by a solid-state metathesis reaction, in which MgCl_2 reacts with Na to form Mg and NaCl, and then Mg reacts with NaSi. Mg_2Si is a semiconducting material that exhibits Li storage and/or thermoelectric properties. Mg_2Si has advantages of being composed of elements with plentiful resources and low toxicity. Mg_2Si has an additional advantage as a lightweight material (cα. 2 g cm~(-3)) when applied to the moving vehicle. Fine Mg_2Si particles are expected to be used as a raw material for the anode of Li-ion batteries and for nanostructured bulk thermoelectric elements. Fine Mg_2Si particles or nanomaterials are considered to exhibit a stable charge-discharge reaction, thereby enhancing the cyclability of batteries. In addition, it was reported in a theoretical study that thermopower would be enhanced by a quantum confinement effect for the nanostructured thermoelectric bulk material comprising grains with diameters in the nanometer range.