Thermoelectric properties of La-filled CoSb3 skutterudites

• Published in: Journal of the Korean Physical Society Vol. 64; no. 7; pp. 1004 - 1008
• Main Authors: Park, Kwan-Ho, Lee, Soonil, Seo, Won-Seon, Baek, Seungsu, Shin, Dong-Kil, Kim, Il-Ho
• Format: Journal Article
• Language: English
• Published: Seoul The Korean Physical Society 01.04.2014; 한국물리학회
• Subjects: Mathematical and Computational Physics; Particle and Nuclear Physics; Physics; Physics and Astronomy; Theoretical; 물리학; Skutterudite; Thermoelectric; Filling
• ISSN: 0374-4884; 1976-8524
• DOI: 10.3938/jkps.64.1004

La-filled skutterudites La z Co 4 Sb 12 (z = 0, 0.1, 0.2, 0.3, 0.4) were prepared by encapsulated melting and hot pressing. The filling effects of La on the transport and the thermoelectric properties of skutterudites were examined. All specimens were transformed to skutterudite phases through subsequent annealing. The intrinsic CoSb 3 had a high positive Seebeck coefficient, but a thermoelectric figure of merit, ZT , of lower than 0.1 due to its low electrical conductivity and high thermal conductivity. However, La-filled CoSb 3 showed degenerate semiconductor behavior and high electrical conductivity, and exhibited n-type conduction because of the excess electrons donated from the La fillers. The Seebeck coefficient increased and then decreased slightly with increasing temperature, and it decreased with increasing La filling content due to increased carrier concentration. The thermal conductivity was reduced significantly by La filling, mainly due to the decrease in the lattice thermal conductivity. ZT = 0.35 was obtained in the temperature range from 623 to 823 K for La 0.2 Co 4 Sb 12 .