Energy-Efficient Synthesis and Superior Thermoelectric Performance of Sb-doped Mg2Si0.3Sn0.7 Solid Solutions by Rapid Thermal Explosion

Abstract

Both low cost and high performance play pivotal roles in the commercial application of thermoelectric materials. Herein, a fast, facile and inexpensive thermal explosion (TE) was utilized to prepare eco-friendly Mg2(Si0.3Sn0.7)1-xSbx solid solutions. The phase transformation during the TE process was investigated. The criterion for differentiating TE from conventional solid-state reaction (SSR) was also illustrated, i.e. whether self-propagating high-temperature synthesis (SHS) happens. With Sb doping, carrier density rises and bipolar conduction in high-temperature range is effectively inhibited. Consequently, the dimensionless thermoelectric figure of merit ZTpeak and ZTave are enhanced, which are decent compared with the reported data. Although a comparative analysis of thermoelectric properties suggests that structural homogenization obtained by SSR instead of TE is conducive to high ZT for Mg2Si0.3Sn0.7 materials, the low-cost TE approach can be easily implemented with attributes of high energy efficiency, fast synthesis and large-scale production, thereby quite worth promoting for other thermoelectric materials.