title: Enhancement of thermoelectric efficiency of CoSb3-based skutterudites by double filling with K and Tl.
abstract: The high-temperature thermoelectric properties of thallium (Tl) and potassium (K) double-filled cobalt antimonide (CoSb3)-based skutterudites with nominal compositions TlxK0.3Co4Sb12 (x = 0.1 - 0.3) were investigated. The filling fraction of Tl in CoSb3 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 x = 0.3 was as high as 4.3 × 10(20) cm(-3) at room temperature. Furthermore, quite low lattice thermal conductivity (as low as 0.9 Wm(-1)K(-1)) was obtained for the sample with x = 0.3, probably because of strong phonon scattering by the Tl and K co-rattling effect, which resulted in a maximum zT of around one at 773 K.
authors.affiliation: Division of Sustainable Energy and Environmental Engineering, Graduate School of Engineering, Osaka University Suita, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Kurosaki
authors.affiliation: Division of Sustainable Energy and Environmental Engineering, Graduate School of Engineering, Osaka University Suita, Japan.
authors.forename: Guanghe
authors.initials: G
authors.lastname: Li
authors.affiliation: Division of Sustainable Energy and Environmental Engineering, Graduate School of Engineering, Osaka University Suita, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Ohishi
authors.affiliation: Division of Sustainable Energy and Environmental Engineering, Graduate School of Engineering, Osaka University Suita, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Muta
authors.affiliation: Division of Sustainable Energy and Environmental Engineering, Graduate School of Engineering, Osaka University Suita, Japan ; Research Institute of Nuclear Engineering, University of Fukui Tsuruga, Japan.
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Yamanaka
keywords: potassium; skutterudite; thallium; thermal conductivity; thermoelectric