Enhanced thermoelectric performance of PbTe bulk materials with figure of merit zT >2 by multi-functional alloying

Abstract

Enhanced thermoelectric performance in large size PbTe bulk materials with figure of merit zT> 2 by multi-functional alloying, Journal of Materiomics (2016),Multi-alloying of Mg and Se in PbTe system is applied for improving zT. A maximum zT of ~ 2.2 at 820 K has been reached. A high zT ~ 2.0 has also been repeated even in a large bulk (~ 200 g). AbstractForming solid solutions in PbTe based materials can simultaneously reduce lattice thermal conductivity and engineer the band structure to enhance the electrical properties. In this work, quarternary alloys of Pb 1-x Mg x Te 0.8 Se 0.2 are designed to improve the figure of merit zT. The significant roles of MgTe in enhancing electrical properties and reducing thermal conductivity of PbTe 0.8 Se 0.2 are investigated. A maximum zT of ~ 2.2 at 820 K has been achieved in PbTe 0.8 Se 0.2 with 8% MgTe. Subsequently, a large dimension bulk (~ 200 g, Φ42 mm × 18 mm) is fabricated and its homogeneity and the repeatability of high zT values are checked. It is shown that high zT ~ 2.0 can also be achieved even in such a large sample. These results highlight the multi-functional roles of quarternary alloying with Mg and Se, and demonstrate the realistic prospect of large-scale commercial fabrication in high performance PbTe-based thermoelectric materials.

Compromise and Synergy in High‐Efficiency Thermoelectric Materials

“…Moreover, new techniques also make it possible to prepare materials with desired composition and structure, and thus the electrical and thermal transport can be manipulated more independently and precisely. After years of efforts, synergistic optimization for high zT s has been accomplished successfully in a few TE materials, such as FeNbSb‐based HH compounds, Pb(Te,Se)‐based alloys, and Bi 2 Te 3 ‐based alloys, etc.…”

Lattice thermal transport in group II-alloyed PbTe

“…Recent experiments show that p-type PbTe alloyed with group II elements (Mg, Ca, Sr and Ba) achieved ZT well above 1.5. [5][6][7][8][9][10][11] It is found in experiments and theoretical calculations that, with group II dopants, electronic properties are improved owing to convergence of multiple valence bands and band gap widening. 8,9 With respect to lattice heat transport, significant reduction of κ l is observed, which was attributed to the all-scale hierarchical architectures-induced phonon scattering due to the presence of solid-solution point defects, nanoscale precipitates, and grain boundaries.…”

Thermoelectric conversion of waste heat from IC engine-driven vehicles: A review of its application, issues, and solutions

“…Thermoelectric material prepared by using quaternary alloys of Pb 1 − x Mg x Te 0.8 Se 0.2 (where x = 0, 0.01, 0.02, 0.03, 0.04, 0.06, and 0.08) with 2% sodium as p‐type dopant achieved a maximum ZT of 2.2 at 547°C. In addition to it, a large bulk sample (~200 g, ϕ 42 mm × 18 mm) is fabricated that achieved ZT in the range of ~1.8 to 2.2 . Horichok et al measured the TE parameters, ie, Seebeck coefficient ( α ), electrical conductivity ( σ ), and thermal conductivity ( k ).…”

“…Recent researches on improvement of ZT -type dopant achieved a maximum ZT of 2.2 at 547°C. In addition to it, a large bulk sample (~200 g, ϕ42 mm × 18 mm) is fabricated that achieved ZT in the range of~1.8 to 2.2 50. Horichok et al51 measured the TE Te 3 , Pb 18 Ag 1 Sb 1 Te 20 , Pb 18 Ag 2 Te 20 , and PbTe-Ag 2 Te.…”