Synergistic Optimization of the Thermoelectric and Mechanical Properti…
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논문명 | Synergistic Optimization of the Thermoelectric and Mechanical Properties of Large-Size Homogeneous Bi0.5Sb1.5Te3 Bulk Samples via Carrier Engineering for Efficient Energy Harvesting |
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저자 | Chul-hee Lee, Peyala Dharmaiah, Dong Hwan Kim, Duck Ki Yoon, Tae Hoon Kim, Sung Ho Song and Soon-Jik Hong |
저널명 | ACS |
게재년월 | 2022/2/8 |
Vol. pp |
Manufacturing an economically viable, efficient commercial
thermoelectric (TE) module is essential for power generation and
refrigeration. However, mediocre TE properties, lack of good mechanical
stability of the material, and significant difficulties involved in the
manufacturing of large-scale powder as well as bulk samples hinder the
potential applications of the modules. Herein, an economically feasible
single-step water atomization (WA) is employed to synthesize BST powder
(2 kg) by Cu doping within a short time and consolidated into large-scale
bulk samples (500 g) for the first time with a diameter of 50 mm and a
thickness of about 40 mm using spark plasma sintering (SPS). The
incorporation of Cu into BST greatly boosts the carrier concentration,
leading to a significant increase in electrical conductivity, and inhibits the
bipolar thermal conductivity by 73%. Synchronously, the lattice
contribution (κL) is greatly reduced by the effective scattering of phonons by comprising fine-grain boundaries and point defects.
Therefore, the peak ZT is shifted to the mid-temperature range and obtained a maximum of ∼1.31 at 425 K and a ZTave of 1.24 from
300 to 500 K for the BSTCu0.05 sample, which are considerably greater than those of the bare BST sample. Moreover, the maximum
compressive mechanical strength of large-size samples manufactured by the WA-SPS process is measured as 102 MPa, which is
significantly higher than commercial zone melting samples. The thermoelectric module assembled with WA-SPS-synthesized
BSTCu0.05 and commercial n-type BTS material manifests an outstanding cooling performance (−19.4 °C), and a maximum output
power of 6.91 W is generated at ΔT ∼ 200 K. These results prove that the BSTCux samples are eminently suitable for the fabrication
of industrial thermoelectric modules.