Tunable microstructures and improved thermoelectric performance of Mg2(Si0.4−xSbxSn0.6) solid solutions

Abstract The single-phase n -type Mg 2 (Si 0.4− x Sb x Sn 0.6 ) (0≤ x ≤0.025) solid solutions were prepared by an induction melting and Spark Plasma Sintering method using buck of Magnesium, Silicon, Tin and Antimony. The unique multiple nanostructures of samples containing nanoscale precipitates and mesoscale grains are formed by the non-equilibrium preparing technique, resulting in remarkably decreasing of lattice thermal conductivities, particularly for samples with the nanoscale precipitates having the size of 20–30 nm. Meanwhile, the electrical properties were increased by Sb-doping. The thermoelectric performance of Sb doped samples with the nanostructures are remarkably improved, and the dimensionless figure of ZT for Mg 2 (Si 0.38 Sb 0.02 Sn 0.6 ) sample shows highest value of 1.30 at 773 K, which is very much higher than that of the non-doped sample.