DOI: 10.3390/nano14060494 ISSN: 2079-4991

Enhanced Thermoelectric Properties of P-Type Sn-Substituted Higher Manganese Silicides

Ming-Xun Jiang, Sang-Ren Yang, I-Yu Tsao, Bayu Satriya Wardhana, Shih-Feng Hsueh, Jason Shian-Ching Jang, Cheng-Lun Hsin, Sheng-Wei Lee
  • General Materials Science
  • General Chemical Engineering

This study introduces Sn-substituted higher manganese silicides (MnSi1.75, HMS) synthesized via an arc-melting process followed by spark plasma sintering (SPS). The influences of Sn concentrations on the thermoelectric performance of Mn(Si1−xSnx)1.75 (x = 0, 0.001, 0.005, 0.01, 0.015) are systematically investigated. Our findings reveal that metallic Sn precipitates within the Mn(Si1−xSnx)1.75 matrix at x ≥ 0.005, with a determined solubility limit of approximately x = 0.001. In addition, substituting Si with Sn effectively reduces the lattice thermal conductivity of HMS by introducing point defect scattering. In contrast to the undoped HMS, the lattice thermal conductivity decreases to a minimum value of 2.0 W/mK at 750 K for the Mn(Si0.999Sn0.001)1.75 sample, marking a substantial 47.4% reduction. Consequently, a figure of merit (ZT) value of ~0.31 is attained at 750 K. This considerable enhancement in ZT is primarily attributed to the suppressed lattice thermal conductivity resulting from Sn substitution.

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