Optimization of Thermoelectric Transport Properties in Nanocomposite MgAgSb-Based Alloys

doi:10.15541/jim20250010

Abstract

Abstract: MgAgSb exhibits excellent thermoelectric performance in the near-room temperature range (300-573K), making it a key research focus for p-type materials in recent years. Due to the low level of atomic doping, the improvement of thermoelectric performance through carrier concentration optimization via doping alone is limited. In this study, Nb and Ta nano-secondary phases were introduced into the MgAg_0.97Sb_0.99 matrix, and two series of alloys, xNb/MgAg_0.97Sb_0.99 and yTa/MgAg_0.97Sb_0.99, were prepared using high-energy ball milling mechanical alloying. The introduction of the Nb nano-secondary phase significantly altered the carrier and phonon transport properties of the material. Due to the presence of the nano-secondary phase Nb in the 0.005Nb/MgAg_0.97Sb_0.99 alloy, its unique microstructure optimized the electrical performance, achieving a maximum power factor of 24.1 μW·cm^-1·K^-2 at 533 K. Additionally, the introduction of the secondary phase enhanced phonon scattering, significantly reducing thermal conductivity. As a result, the 0.005Nb/MgAg_0.97Sb_0.99 sample achieved the optimal zT of 1.09 at 483 K, improved by ~9.0% compared to MgAg_0.97Sb_0.99 at the same temperature. Furthermore, the introduction of Ta, a homologue of Nb, into the MgAg_0.97Sb_0.99 sample showed a similar trend, with 0.005Ta/MgAg_0.97Sb_0.99 achieving zT of 1.02 at 483 K. This study demonstrates an effective nanocomposite strategy for optimizing thermoelectric transport properties and enhancing the thermoelectric performance of p-type MgAg_0.97Sb_0.99.

Key words: MgAgSb-based compound, secondary phase, alloying, thermoelectric performance

CLC Number:

TQ174

WU Huaxin, ZHANG Qihao, YAN Haixue, WANG Lianjun, JIANG Wan. Optimization of Thermoelectric Transport Properties in Nanocomposite MgAgSb-Based Alloys[J]. Journal of Inorganic Materials, DOI: 10.15541/jim20250010.

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