Thermoelectric Performance of Rapidly Microwave-Synthesized α‑MgAgSb with SnTe Nanoinclusions

• Published in: Chemistry of materials 2019-04, Vol.31 (7), p.2421-2430
• Main Authors: Xin, Jiwu, Yang, Junyou, Li, Sihui, Basit, Abdul, Sun, Bingyang, Li, Suwei, Long, Qiang, Li, Xin, Chen, Ying, Jiang, Qinghui
• Format: Article
• Language: English
• ISSN: 0897-4756; 1520-5002
• DOI: 10.1021/acs.chemmater.8b05014

α-MgAgSb (α-MAS) has recently been discovered to be a promising p-type thermoelectric material owing to its earth-abundant and nontoxic nature. However, there are two main disadvantages hindered the large-scale application of α-MAS, one is the single α-MAS phase prepared by conventional method requires for an extended period of time, and the other is the severely bipolar effect thus poor electric properties. In this scenario, we have presented an effective approach typified by SnTe nanocompositing to significantly enhance the thermoelectric performance of the rapidly microwave-synthesized α-MAS system. Specifically, the pure α-MAS compound was first produced by using a rapidly microwave synthesis. After the initial preparation, high-quality SnTe nanoparticles fabricated by a facile solvothermal method were incorporated into the microwave-synthesized α-MAS matrix. It is deserve to be mentioned that the rapidly microwave synthesis purifies the single α-MAS phase and allows the preparative time to be diminished from over 2 weeks to as little as 5 days. Moreover, the severe bipolar effect of pristine α-MAS has been retarded effectively by the following step typified by compositing SnTe nanoinclusions, leading to a large Seebeck coefficient, thus significantly enhanced a power factor in α-MAS/SnTe-composited system. Concurrently, the lattice thermal conductivity has also been greatly reduced because of the extra phonon scattering because of the multiscale hierarchical architecture (e.g., SnTe nanostructures, high-density stacking faults, and elastic strain fields). Eventually, an enhanced figure of merit ZT of ∼1 at 548 K, which increases by ∼53% compared with pristine α-MAS, has been achieved in the 3 at % SnTe-composited sample. This work impels the potential application of the α-MAS thermoelectric material as a robust candidate for a waste heat recovery below 573 K.