Thermoelectric Performance of Ca[sub.2]Si Synthesized by High-Temperature Melting

• Published in: Coatings (Basel) Vol. 13; no. 8
• Main Authors: Tan, Wenjie, Zhang, Jiarui, Ma, Fukun, Jing, Min, Xing, Ningning
• Format: Journal Article
• Language: English
• Published: MDPI AG 01.08.2023
• Subjects: Electric properties; Force and energy; Thermoelectricity
• ISSN: 2079-6412; 2079-6412
• DOI: 10.3390/coatings13081426

Ca[sub.2]Si was successfully synthesized via a high-temperature melting furnace and a spark plasma sintering process, allowing its thermoelectric properties to be studied. High-temperature melting furnaces were utilized to inhibit the volatilization of Ca elements during the preparation stage, ensuring the production of high-purity Ca[sub.2]Si. The resistivity of Ca[sub.2]Si increased gradually with rising temperature and reached 12 mΩ·cm at 873 K, demonstrating semi-metallic characteristics. In the temperature range of 323 K–873 K, Ca[sub.2]Si displayed relatively low total thermal conductivity, from 1.1 to 1.7 W·m[sup.−1]·K[sup.−1]. Nevertheless, Ca[sub.2]Si attained a maximum thermoelectric figure of merit (ZT) of 0.1 due to the atypical behavior and electrical properties of semiconductors. In contrast, Mg[sub.2]Si achieved a ZT value of 0.32 at 873 K, owing to its exceptional Seebeck coefficient.