Ultra-Low Lattice Thermal Conductivity Enables High Thermoelectric Properties in Cu and Y Codoped SnTe via Multi-Scale Composite Nanostructures

Abstract

The eco-friendly thermoelectric material SnTe has recently gained immense attention due to its excellent thermoelectric properties and potential. However, its thermoelectric properties are limited by the inherent high carrier concentration (low Seebeck coefficient) and high thermal conductivity. Herein, we further introduce rare-earth element Y on top of the conventional Cu alloying to more effectively modulate its microstructure and thermal transport properties. The experimental results reveal that Y doping gives rise to band convergence, endowing Sn 1−x Y x Te-5%Cu 2 Te with an increased power factor of ∼22.14 μW cm −1 K −2 . Meanwhile, the introduced abundant Y/ Y 2 Te 3 multiscale composite nanostructures in the matrix greatly enhance phonon scattering, resulting in an ultra-low lattice thermal conductivity of ∼0.43 W m −1 K −1 . Consequently, these combined effects resulted in a peak ZT value of 1.27 at 823 K in Sn 0.97 Y 0.03 Te-5%Cu 2 Te. An enhancement of nearly 217% is achieved compared to pristine SnTe, which greatly improves the thermoelectric properties of SnTe-based materials.

Ultra-Low Thermal Conductivity and Improved Thermoelectric Performance in Tungsten-Doped GeTe

“…Ultimately, we achieved a significant improvement in the peak power factor (PF peak ) at 673 K up to ~43 μW cm −1 K −2 and the optimization of the ultra-low lattice thermal conductivity of 0.14 W m −1 K −1 at 673 K for a W doping concentration of x = 0.002. This contributes to a remarkable enhancement in the average ZT value up to ~0.76 within the temperature range of 573–723 K and represents a 17% increase compared to the GeTe matrix, thereby improving the thermoelectric performance of GeTe-based materials overall [ 7 , 9 , 27 ].…”

“…In recent years, GeTe has emerged as a typical IV-VI group semiconductor thermoelectric material [6]. Benefiting from its crystal structure closely resembling that of SnTe [7][8][9] and PbTe [10][11][12], GeTe exhibits a relatively high intrinsic Seebeck coefficient. However, due to the environmental toxicity of PbTe, poor mechanical and thermoelectric properties of SnTe, and the fact that the peak ZT value of GeTe-based materials can exceed 0.8 in Nanomaterials 2024, 14, 722 2 of 11 the temperature range of 300-750 K, GeTe has become a hot topic in thermoelectric research.…”

Enhancement in Thermoelectric Performance in Ti-doped Yb0.4Co4Sb12 Skutterudites via Carrier Optimization and Phonon Anharmonicity

“…Nevertheless, the interdependency of TE parameters of σ, S , and κ total prevents the decoupling of the former and latter terms. However, many strategic efforts have been made such as band convergence, electron filtering, nanocomposites, modulation doping, multiscale precipitation, and anharmonicity, which led to successful enhancement in S 2 σ and lowering the thermal conductivity successfully. In this context, though the state-of-the-art materials, namely, Bi 2 Te 3 , − PbTe, ,, PbSe, , GeTe, , SnSe, , SnTe, and half-Heusler, have been known for their superior thermoelectric performance within the operating temperature range, most of them could not be used for large-scale applications because of the costly and toxic constituent elements.…”