Understanding the High Thermoelectric Performance of Mg3Sb2‐Mg3Bi2 Alloys

n‐Type Mg 3 Sb 2 ‐Mg 3 Bi 2 alloys are some of the most promising thermoelectric materials in the low–mid temperature range. While discovered relatively recently, these materials have garnered intense attention, and numerous papers from the international thermoelectric community have been published in a relatively short period of time. As with all materials, detailed insights into the underlying mechanisms that contribute to these alloys’ distinguished thermoelectric properties are important for future researchers to push the performance of this material to new heights. Herein, experimental studies on the role defects, synthesis conditions, electronic band structure, and microstructure along with future prospects arecompiled to establish a guide for fully exploiting the potential of this material system. Considering the limited number of n‐type thermoelectric materials with this performance for low‐grade heat recovery and cooling technologies, further development of the Mg 3 Sb 2 ‐Mg 3 Bi 2 alloys is an important step toward commercial applications of thermoelectric materials, including cooling technologies and waste heat recovery applications.