Enhancement of Thermoelectric Behavior of La sub(0.5)Co sub(4)Sb sub(12-x)Te sub(x) Skutterudite Materials

• Published in: Metallurgical and materials transactions. A, Physical metallurgy and materials science Physical metallurgy and materials science, 2017-06, Vol.48 (6), p.3073-3081
• Main Authors: Said, Suhana Mohd, Bashir, Mohamed Bashir Ali, Sabri, Mohd Faizul Mohd, Miyazaki, Yuzuru, Shnawah, Dhafer Abdul Ameer, Hakeem, Abbas Saeed, Shimada, Masanori, Bakare, Akolade Idris, Ghazali, Nik Nazri Nik, Elsheikh, Mohamed Hamid
• Format: Article
• Language: English
• Subjects: Antimony; Coefficients; Doping; Electrical resistivity; Metallurgy; Physical metallurgy; Thermal conductivity; Thermoelectricity
• ISSN: 1073-5623; 1543-1940
• DOI: 10.1007/s11661-017-4058-1

In this work, the effects of Te doping on the microstructure and thermoelectric properties of the partially filled skutterudite La sub(0.5)Co sub(4)Sb sub( 12) compounds have been examined. La sub(0.5)Co sub(4)Sb sub( 12-x)Te sub(x) skutterudite compounds were synthesized by a combination of the mechanical alloying technique and spark plasma sintering processing, which resulted in partial substitution of Te atoms in Sb sites. The XRD results showed that all the Te-doped bulk samples were composed of a major phase of the Co sub(4)Sb sub(12) skutterudite with a small amount of CoSb sub(2) and Sb as the secondary phases. Thermoelectric measurements of the consolidated samples were examined in a temperature range of 300 K to 800 K (27 degree C to 527 degree C). With the La sub(0.5)Co sub(4)Sb sub( 11.7)Te sub(0.3) sample, the highest absolute Seebeck coefficient of 300 mu V/K was obtained at 404 K (131 degree C) and the lowest lattice thermal conductivity of 2 W/mK was achieved at 501 K (228 degree C). Moreover, the minimum electrical resistivity of 19.7 mu Omega m was recorded at 501 K (228 degree C) for La sub(0.5)Co sub(4)Sb sub( 11.5)Te sub(0.5) sample. The effect of the secondary phases was negligible for the electrical resistivity, and between 0.5 to 1.6 pct for the thermal conductivity. Thus, the highest figure of merit, ZT = 0.47, was obtained at 792 K (519 degree C) for La sub(0.5)Co sub(4)Sb sub( 11.5)Te sub(0.5) sample due to a significant reduction in electrical resistivity and a moderate increase in the absolute Seebeck coefficient.