Abstract
Skutterudite compounds such as Co antimonite (CoSb3) contain cage-like voids inside crystal structure, which can be completely or partially filled with various different atoms, including group 13 elements. The multiple filling approach is known as an effective way of reducing lattice thermal conductivity (κlat), which results in a high value of the thermoelectric dimensionless figure of merit (zT). In this work, enhanced zT was achieved for the Ga and In co-added CoSb3 samples with a preferable microstructure and the nominal composition (Ga0.8In0.2)xCo4Sb12 (x = 0.05−0.45). Although all added In atoms occupied exclusively the void sites, the Ga species filled both the void and Sb sites of CoSb3. Moreover, Ga atoms added in the quantities exceeding the solubility limit precipitated as GaSb nanoparticles. The sample with x = 0.45 was characterized by the largest filling factions of Ga and In as well as the unique microstructure, consisting of microscale grains of the skutterudite phase and corresponding amounts of the GaSb nanoparticles. The Ga and In co-added skutterudite samples with optimized chemical composition and microstructure maintained high carrier mobility and sufficiently low κlat values, resulting in zT > 1.1, one of the best values for the skutterudites filled with group 13 elements.
Highlights
Thermoelectric (TE) devices, which can convert waste heat into electrical power, have been considered clean and sustainable power sources.[1]
The multiple filling approach is known as an effective way of reducing lattice thermal conductivity, which results in a high value of the thermoelectric dimensionless figure of merit
Our group has previously investigated the TE properties of Ga and In co-added CoSb3-based skutterudites[27] and found that (1) Ga and In could be simultaneously introduced into the voids of the skutterudite structure; (2) Ga could occupy Sb sites; and (3) Ga and In added in the amounts exceeding the filling limit precipitated as (Ga,In)Sb nanoinclusions. These three phenomena contributed to the κlat reduction significantly, and the maximum value of zT close to unity was obtained for the nominal composition Ga0.20In0.30Co4Sb12.27 In the present study, we have attempted to improve the zT of Ga and In co-added CoSb3 by optimizing both its chemical composition and microstructure
Summary
Since Ga indicates the unique behavior in CoSb3 such as dual-site occupancy and the desirable electronic band engineering, it is worth studying as a co-dopant with In in CoSb3-based skutterudites.[29,33,34,45] Our group has previously investigated the TE properties of Ga and In co-added CoSb3-based skutterudites[27] and found that (1) Ga and In could be simultaneously introduced into the voids of the skutterudite structure; (2) Ga could occupy Sb sites; and (3) Ga and In added in the amounts exceeding the filling limit precipitated as (Ga,In)Sb nanoinclusions These three phenomena contributed to the κlat reduction significantly, and the maximum value of zT close to unity was obtained for the nominal composition Ga0.20In0.30Co4Sb12.27 In the present study, we have attempted to improve the zT of Ga and In co-added CoSb3 by optimizing both its chemical composition and microstructure.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
