Preparation of High-Performance Mn-Doped SnTe Materials at High Pressure and High Temperature

SnTe is an environmentally friendly medium-temperature thermoelectric material, but its inherent low power factor (PF) and high lattice thermal conductivity severely limit its application. In this study, based on the fact that Mn doping can induce band convergence, the high-pressure and high-temperature (HPHT) synthesis method was used to optimize the sample preparation and shorten the synthesis cycle to 30 min. The results show that the Sn0.93Mn0.10Te sample achieves the maximum PF value of 34.00 μW cm–1 K–2 at 775 K and PFave value of 21.36 μW cm–1 K–2 between 300–875 K. Microstructure analysis shows that the high-pressure synthesis method introduces abundant grain boundaries, various grain sizes, multiple defects, and pore structures into the sample. These microscopic crystal structures can effectively scatter phonons and lower the lattice thermal conductivity. The modification of these micromorphologies results in the Sn0.92Mn0.11Te sample attaining a minimum lattice thermal conductivity of 0.45 W m–1 K–1 at 625 K. The thermoelectric figure of merit (zT) of sample Sn0.92Mn0.11Te reaches a maximum value of 1.1 at 775 K, and the zTave reaches 0.63 in the range of 300–875 K. This study indicates that the synergistic effect of Mn element doping and microstructure modification can effectively optimize the thermoelectric transport performance of SnTe materials

Enhanced Thermoelectric Properties of Double-Filled CoSb₃ via High-Pressure Regulating

It has been discussed for a long time that synthetic pressure can effectively optimize thermoelectric properties. The beneficial effect of synthesis pressures on thermoelectric properties has been discussed for a long time. In this paper, it is theoretically and experimentally demonstrated that appropriate synthesis pressures can increase the figure of merit (ZT) through optimizing thermal transport and electronic transport properties. Indium and barium atoms double-filled CoSb₃ samples were prepared use high-pressure and high-temperature technique for half an hour. X-ray diffraction and some structure analysis were used to reveal the relationship between microstructures and thermoelectric properties. In_0.15Ba_0.35Co₄Sb₁₂ samples were synthesized by different pressures; sample synthesized by 3 GPa has the best electrical transport properties, and sample synthesized by 2.5 GPa has the lowest thermal conductivity. The maximum ZT value of sample synthesized by 3.0 GPa reached 1.18