Enhanced Thermoelectric Performance in the Ba0.3Co4Sb12/InSb Nanocomposite Originating from the Minimum Possible Lattice Thermal Conductivity

Ghosh, S and Shankar, G and Karati, A and Werbach, K and Rogl, G and Rogl, P and Bauer, E and Murty, BS and Suwas, S and Mallik, RC (2020) Enhanced Thermoelectric Performance in the Ba0.3Co4Sb12/InSb Nanocomposite Originating from the Minimum Possible Lattice Thermal Conductivity. In: ACS Applied Materials and Interfaces, 12 (43). pp. 48729-48740.

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Abstract

The thermoelectric efficiency of skutterudite materials can be improved by lowering the lattice thermal conductivity via the uniform dispersion of a nanosized second phase in the matrix of filled Co4Sb12. In this work, nanocomposites of Ba0.3Co4Sb12 and InSb were synthesized using ball-milling and spark plasma sintering. The thermoelectric transport properties were studied from 4.2 to 773 K. The InSb nanoparticles of �20 nm were found to be dispersed in the Ba0.3Co4Sb12 grains with a few larger grains of about 10 μm due to the agglomeration of the InSb nanoparticles. The +2 oxidation state of Ba in Co4Sb12 resulted in a low electrical resistivity, �, value of the matrix. The enhancement of the Seebeck coefficient, S, and the electrical resistivity values of Ba0.3Co4Sb12 with the addition of InSb can be credited to the energy-filtering effect of electrons with low energy at the interfaces. The power factor of the composites could not be enhanced compared to the matrix because of the very high � value. A minimum possible lattice thermal conductivity (0.45 W/m·K at 773 K) was achieved due to the combined effect of rattling of Ba atoms in the voids and enhanced phonon scattering at the interfaces induced by nanosized InSb particles. As a result, the (InSb)0.15 + Ba0.3Co4Sb12 composite exhibited improved thermoelectric properties with the highest zT of 1.4 at 773 K and improved mechanical properties with a higher hardness, higher Young's modulus, and lower brittleness. ©

Item Type:	Journal Article
Publication:	ACS Applied Materials and Interfaces
Publisher:	American Chemical Society
Additional Information:	The copyright of this article belongs to American Chemical Society
Keywords:	Ball milling; Barium; Crystal lattices; Elastic moduli; Electric conductivity; Fracture mechanics; III-V semiconductors; Indium antimonides; Nanocomposites; Nanoparticles; Semiconducting antimony compounds; Sintering; Thermal conductivity; Thermoelectricity, Energy filtering; Lattice thermal conductivity; Skutterudite materials; Thermoelectric efficiency; Thermoelectric performance; Thermoelectric properties; Thermoelectric transport properties; Uniform dispersions, Cobalt compounds
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy) Division of Physical & Mathematical Sciences > Physics
Date Deposited:	22 Dec 2020 10:46
Last Modified:	22 Dec 2020 10:46
URI:	http://eprints.iisc.ac.in/id/eprint/67468

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