AUTHOR=Kurosaki Ken , Li Guanghe , Ohishi Yuji , Muta Hiroaki , Yamanaka Shinsuke 

TITLE=Enhancement of thermoelectric efficiency of CoSb3-based skutterudites by double filling with K and Tl

JOURNAL=Frontiers in Chemistry

VOLUME=2

YEAR=2014

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2014.00084

DOI=10.3389/fchem.2014.00084

ISSN=2296-2646

ABSTRACT=<p>The high-temperature thermoelectric properties of thallium (Tl) and potassium (K) double-filled cobalt antimonide (CoSb<sub>3</sub>)-based skutterudites with nominal compositions Tl<sub>x</sub>K<sub>0.3</sub>Co<sub>4</sub>Sb<sub>12</sub> (<italic>x</italic> = 0.1 − 0.3) were investigated. The filling fraction of Tl in CoSb<sub>3</sub> was enhanced by co-filling with K, which resulted in all of the samples showing the filled-skutterudite single phase. Owing to the high filling ratio, the carrier concentration in the sample with <italic>x</italic> = 0.3 was as high as 4.3 × 10<sup>20</sup> cm<sup>−3</sup> at room temperature. Furthermore, quite low lattice thermal conductivity (as low as 0.9 Wm<sup>−1</sup>K<sup>−1</sup>) was obtained for the sample with <italic>x</italic> = 0.3, probably because of strong phonon scattering by the Tl and K co-rattling effect, which resulted in a maximum <italic>zT</italic> of around one at 773 K.</p>