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摘要
Thermoelectric materials that convert electric energy and thermal energy are applied as functional materials in waste heat recovery and semiconductor refrigeration. Research on conventional thermoelectric materials has reached maturity; further development of such materials is hampered by the high cost of raw materials and low thermoelectric conversion efficiency. To overcome these limitations, Mg3(Sb, Bi)2 Zintl phases have attracted extensive attention since their discovery and have been widely applied as thermoelectric materials because of their low cost and intrinsic low thermal conductivity. In addition, N-type Mg3(Sb, Bi)2-based conduction materials, having a high Seebeck coefficient owing to high energy band degeneracy, are hypothesized to be more effective than conventional medium- and low-temperature thermoelectric materials. However, the application of Mg3(Sb, Bi)2-based thermoelectric materials is limited because of the low carrier concentration caused by the large bandgap and the low thermal stability due to Mg vacancies. In addition to the maintenance of initial low thermal conductivity of such materials, researchers have continually tried to improve the electrical transport performance and thermal stability by employing different preparation processes and by conducting component and structure optimization. At present, the maximum ZT value of Mg3(Sb, Bi)2-based thermoelectric materials is above 1. 8, and the conversion efficiency of the Mg3(Sb, Bi)2-based thermoelectric devices has been comparable to that of conventional low-temperature thermoelectric materials. This paper summarizes the physical properties and preparation methods of Mg3(Sb, Bi)2-based thermoelectric materials. The research progress on different optimization methods to prepare Mg3(Sb, Bi)2-based thermoelectric materials is discussed in detail, and possible future developments of the materials are presented. ? 2023 Cailiao Daobaoshe/ Materials Review.
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