Half-Heusler alloys as emerging high power density thermoelectric cooling materials

Abstract

To achieve optimal thermoelectric performance, it is crucial to manipulate the scattering processes within materials to decouple the transport of phonons and electrons. In half-Heusler (hH) compounds, selective defect reduction can significantly improve performance due to the weak electron-acoustic phonon interaction. This study utilized Sb-pressure controlled annealing process to modulate the microstructure and point defects of Nb0.55Ta0.40Ti0.05FeSb compound, resulting in a 100% increase in carrier mobility and a maximum power factor of 78 µW cm−1 K−2, approaching the theoretical prediction for NbFeSb single crystal. This approach yielded the highest average zT of ~0.86 among hH in the temperature range of 300-873 K. The use of this material led to a 210% enhancement in cooling power density compared to Bi2Te3-based devices and a conversion efficiency of 12%. These results demonstrate a promising strategy for optimizing hH materials for near-room-temperature thermoelectric applications.

Decoupling Carrier-Phonon Scattering Boosts the Thermoelectric Performance of n-Type GeTe-Based Materials

“…In GeTe materials, heavy alloying, such as AgBiSe 2 -alloying, AgBiTe 2 -alloying, and Pb/Bi/Se-alloying, is used to realize the p–n transition, which induces the multidimensional defects and strengthens both carrier and phonon scattering. , The strong carrier-phonon scattering contributes to low μ / κ l (<410.7 cm 3 V –1 s –1 W –1 K) and ZT < 0.6. − It should be noted that the carrier MFP (0.1–10 nm) and the phonon MFP (0.1–1000 nm) of GeTe do not overlap exactly, , which reveals the possibility of increasing μ / κ l by decoupling carrier-phonon scattering to realize high ZT .…”

Transport phenomena of TiCoSb: defect induced modification in the structure and density of states

“…15,16 Zhu et al have revealed that TE devices, made from HH alloys, are potential materials for TE cooling with high power density. 17 TE materials are used in aerospace for power generation or thermal management in space missions and unmanned aerial vehicles (UAVs) in the absence of traditional power sources. 18–20 HH alloy-based materials viz.…”

Calculation of Seebeck coefficient and thermal electric conductivity in single-layer NiI2 with LDA+U method

“…Thermoelectric materials have become one of the hot issues in material science that can be applied to reduce waste heat [1]. Several theoretical approaches have been conducted to find suitable candidates for thermoelectric materials, such as Heusley alloy [2,3], metal dichalcogenides [4,5], and many others. Two different quantities can be investigated to predict the quality of thermoelectric materials, namely, the Seebeck and Nernst coefficients.…”