Facile Route to High-Performance SnTe-Based Thermoelectric Materials: Synergistic Regulation of Electrical and Thermal Transport by In Situ Chemical Reactions

Abstract

In this work, a composite product of Mn-substituted SnTe, SnO 2 nanoparticles, and MnTe-supersaturated precipitates has been fabricated by a simple in situ reaction between SnTe and MnO 2 for the first time. Benefiting from the synergistic effect induced by the product of in situ reaction, a remarkable improvement in the thermoelectric performance has been achieved. On the one hand, Mn substitution in SnTe can effectively modify the band structure and enhance the electrical properties of SnTe; on the other hand, the thermal transport can also be dramatically suppressed by in situ reaction-derived multiscale phonon scattering by point defects, SnO 2 nanoparticles, and supersaturated MnTe precipitates. Ultimately, a maximum ZT of ∼1.5 at 873 K has been achieved in the SnTe + 10 mol % MnO 2 sample, which increases by 224% in comparison with the pristine SnTe, representing one of the best results ever reported for SnTe-based thermoelectric materials.

High Thermoelectric Performance of SnTe via In Doping and Cu1.75Se Nanostructuring Approach

“…142% improvement over the pristine Sn 0.96 In 0.04 Te mainly originates from the greatly lowered κ L due to the phonon scattering from the nanoinclusions of Cu 1.75 Se in the composites. Compared with the reported SnTe nanocomposites with Z T max ≤ 1.6 ,, seen in Figure (b), our samples Sn 0.96 In 0.04 Te-3%Cu 2 Se, Sn 0.96 In 0.04 Te-5%Cu 1.75 Se, and Sn 0.96 In 0.04 Te-7%Cu 1.75 Se have the largest Z T max of 1.7 at 823 K.…”

“…142% improvement over the pristine Sn 0.96 In 0.04 Te mainly originates from the greatly lowered κ L due to the phonon scattering from the nanoinclusions of Cu 1.75 Se in the composites. Compared with the reported SnTe nanocomposites with ZT max ≤ 1.6 4,15,17…”

“…16 Ten mol % MnO 2 introduced in SnTe causes a maximum ZT of ∼1.5. 17 The highest ZT of 1.3 is reported as 2%Ag and 2%In is incorporated in SnTe-based materials. 18 Here, the effect of In-doping and incorporation of Cu 1.75 Se nanostructuring on thermoelectric properties for SnTe is studied.…”

“…SnTe-CdSe nanocomposite is reported to have ZT of 1.3 . Ten mol % MnO 2 introduced in SnTe causes a maximum ZT of ∼1.5 . The highest ZT of 1.3 is reported as 2%Ag and 2%In is incorporated in SnTe-based materials …”

General strategies to improve thermoelectric performance with an emphasis on tin and germanium chalcogenides as thermoelectric materials

“…This process reduces the carrier concentration of SnTe and increases the Seebeck coefficient. Sn 1.03− x Mn x Te (with, x = 0, 0.05, 0.07, 0.09, 0.11) class of materials was studied over a temperature range of 300 K to 900 K, and an enhanced ZT ∼ 1.35 was reported for the composition of Sn 0.94 Mn 0.09 Te at 873 K. 97 Zhou et al 216 synthesized Mn-substituted SnTe and SnO 2 nanoinclusions by in situ chemical reactions between the MnO 2 additives and SnTe matrix. They achieved a ZT of ∼1.5 at 873 K in the SnTe + 10 mol% MnO 2 sample.…”