Enhanced Mechanical Properties of Na0.02Pb0.98Te/MoTe2 Thermoelectric Composites Through in-Situ-Formed MoTe2

Optimization of Mechanical and Thermoelectric Properties of SnTe-Based Semiconductors by Mn Alloying Modulated Precipitation Evolution

Multiscale defects engineering offers a promising strategy for synergistically enhancing the thermoelectric and mechanical properties of thermoelectric semiconductors. However, the specific impact of individual defects, in particular precipitation, on mechanical properties remains ambiguous. In this work, the mechanical and thermoelectric properties of Sn1.03- x Mnx Te (x = 0-0.30) semiconductors are systematically studied. Mn-alloying induces dense dislocations and Mn nano-precipitates, resulting in an enhanced compressive strength with x increased to 0.15. Quantitative calculations are performed to assess the strengthening contributions including grain boundary, solid solution, dislocation, and precipitation strengthening. Due to the dominant contribution of precipitation strengthening, the yield strength of the x = 0.10 sample is improved by ≈74.5% in comparison to the Mn-free Sn1.03 Te. For x ≥ 0.15, numerous MnTe precipitates lead to a synergistic enhancement of strength-ductility. In addition, multiscale defects induced by Mn alloying can scatter phonons over a wide frequency spectrum. The peak figure of merit ZT of ≈1.3 and an ultralow lattice thermal conductivity of ≈0.35 Wm-1  K-1 are obtained at 873 K for x = 0.10 and x = 0.30 samples respectively. This work reveals tha precipitation evolution optimizes the mechanical and thermoelectric properties of Sn1.03- x Mnx Te semiconductors, which may hold potential implications for other thermoelectric systems.

Recent Progress in Multiphase Thermoelectric Materials

Thermoelectric materials, which directly convert thermal energy to electricity and vice versa, are considered a viable source of renewable energy. However, the enhancement of conversion efficiency in these materials is very challenging. Recently, multiphase thermoelectric materials have presented themselves as the most promising materials to achieve higher thermoelectric efficiencies than single-phase compounds. These materials provide higher degrees of freedom to design new compounds and adopt new approaches to enhance the electronic transport properties of thermoelectric materials. Here, we have summarised the current developments in multiphase thermoelectric materials, exploiting the beneficial effects of secondary phases, and reviewed the principal mechanisms explaining the enhanced conversion efficiency in these materials. This includes energy filtering, modulation doping, phonon scattering, and magnetic effects. This work assists researchers to design new high-performance thermoelectric materials by providing common concepts.