低晶格热导率热电材料

热电材料能够实现热能和电能之间的直接相互转换，被视为具有广泛应用前景的清洁能源材料。热电材料的规模化应用主要受制于其较低的能量转换效率，因此提高材料的热电性能仍然是当前研究的重心。优化电输运性能和降低晶格热导率是提升热电性能的两条主要途径。相较于强关联的电导率和塞贝克系数，晶格热导率相对可以独立调控，因此如何获得低晶格热导率成为热电材料研究的热点。文章综述了利用晶体缺陷包括点缺陷、线缺陷、面缺陷、填隙原子等降低晶格热导率的方法及其声子散射机制，并对低维、低声速、低比热等热电材料的研究进展及其具有本征低晶格热导率的机制进行了介绍。

Thermoelectric materials with low lattice thermal conductivity

Thermoelectric materials can directly convert heat into electricity and thus have broad prospects for commercial applicationas clean energy materials. However, the low energy conversion efficiency still limits their large-scale applications. It is still a fundamental issue of thermoelectric materials to improve their thermoelectric properties. Optimizing the electrical transport properties and lowering the lattice thermal conductivity are the main ways to improve the thermoelectric performance. In contrast to the strongly correlated electrical conductivity and Seebeck coefficient, it is relatively independent to modulate the lattice thermal conductivity. Hence, it is a research hotspot to realize low lattice thermal conductivity in the field of thermoelectricity. This review summarized the methods lowering the lattice thermal conductivity by means of crystal defects, such as point defects, line defects, face defects, and interstitial atoms, and presented the related phonon scattering mechanisms. In addition, the exploration of thermoelectric materials with low dimensions, low acoustic velocities, or low specific heats, as well as the underlying mechanism for their intrinsic low lattice thermal conductivities are introduced in this review.