An effective synthesis route for high-performance α-MgAgSb thermoelectric material

α-MgAgSb has been receiving attention as a thermoelectric material due to its high performance at 300–550 K. A MgAgSb sample synthesized by melting the constituent elements is known to contain secondary phases, which can be diminished by long-term heat treatment. However, less effort has been devoted to investigating the secondary phases and exploring an effective synthesis route to improve the sample purity. In this work, we showed that an as-melted sample comprised α-MgAgSb and large amounts of Ag₃Sb and Mg₄AgSb₃. The secondary phases were successfully diminished/reacted through short-term ball milling and sintering processes. Secondary phases were further reduced by decreasing the starting Ag content, leading to the enhanced dimensionless figure of merit ZT of 0.4 at 300 K and 0.7 at 450 K. The synthesis route without long-term heat treatment is expected to contribute to efficient production of α-MgAgSb. Graphical abstract: [Figure not available: see fulltext.]