Progress and prospects of plastic thermoelectric materials

Abstract

In recent years, significant progress has been made in the research of plastic thermoelectric materials, exemplified by Ag₂S-based alloys. These materials exhibit excellent room-temperature plasticity due to their low slipping barrier energy and high cleavage energy, with synergistic enhancements in plasticity and thermoelectric properties achievable through alloying and doping strategies. The latest study on Mg₃Bi₂-based single crystals demonstrated superior performance in terms of plastic deformation capability and room-temperature thermoelectric properties. Microstructural characterization and theoretical calculation have revealed the crucial role of dislocation glide in the plastic deformation process of Mg₃Bi₂ single crystals, particularly the low slipping barrier energies observed in multiple slip systems. Importantly, the Te-doped single-crystalline Mg₃Bi₂ shows a power factor of ~55 μW cm^-1 K^-2 and <i>zT</i> of ~0.65 at room temperature along the <i>ab</i> plane, which outperforms the existing ductile thermoelectric materials. These findings not only deepen the understanding of microscopic deformation mechanisms in plastic thermoelectric materials but also establish an important foundation for optimizing material properties and developing novel flexible thermoelectric devices. Future applications of these materials in practical devices still face challenges in thermal stability, chemical stability, and interfacial contact. Addressing these issues will promote the application of plastic thermoelectric materials in the field of flexible electronics.