Thermoelectric properties enhancement of Ba0·2Co4Sb12 through dispersion of GaSb inclusions

Sanyukta Ghosh; Gyan Shankar; Anirudha Karati; Gerda Rogl; Peter Rogl; Ernst Bauer; B. S. Murty; Satyam Suwas; Ramesh Chandra Mallik

doi:10.1016/j.physb.2020.412440

Thermoelectric properties enhancement of Ba_0·2Co₄Sb₁₂ through dispersion of GaSb inclusions

Sanyukta Ghosh, Gyan Shankar, Anirudha Karati, Gerda Rogl, Peter Rogl, Ernst Bauer, B. S. Murty, Satyam Suwas, Ramesh Chandra Mallik

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2 Scopus citations

Abstract

The combined effects of Ba-filling the voids and GaSb nanophase incorporation in the matrix of Co₄Sb₁₂ have been studied for thermoelectric properties. High energy ball-milling was used to disperse GaSb in Ba_0·2Co₄Sb₁₂. A slight off-stoichiometry between Co and Sb generated CoSb₂ and CoSb phases. Electron back-scattered diffraction showed nanocrystalline (50–200 nm) GaSb grains uniformly distributed on the matrix along with a few large grains (1–3 μm). The low electrical resistivity (ρ) of Ba_0·2Co₄Sb₁₂ can be attributed to the +2 oxidation state of Ba. The increase in ρ of composites occurred due to the enhanced scattering of charge carriers at interfaces. No significant change in Seebeck coefficients was found in composites. The simultaneous effect of anharmonicity induced by Ba-filler in the voids and the enhanced interfaces between GaSb and the matrix reduced lattice thermal conductivity and brought about an improvement in zT from 0.75 to ~1.0 for (GaSb)_0.4+Ba_0·2Co₄Sb₁₂ at 773 K.

Original language	English
Article number	412440
Journal	Physica B: Physics of Condensed Matter
Volume	606
DOIs	https://doi.org/10.1016/j.physb.2020.412440
State	Published - Apr 1 2021
Externally published	Yes

Keywords

Bloch-grüneisen relation
Callaway's equation
EBSD
Lattice thermal conductivity
Nanocomposite
Thermoelectrics

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title = "Thermoelectric properties enhancement of Ba0·2Co4Sb12 through dispersion of GaSb inclusions",

abstract = "The combined effects of Ba-filling the voids and GaSb nanophase incorporation in the matrix of Co4Sb12 have been studied for thermoelectric properties. High energy ball-milling was used to disperse GaSb in Ba0·2Co4Sb12. A slight off-stoichiometry between Co and Sb generated CoSb2 and CoSb phases. Electron back-scattered diffraction showed nanocrystalline (50–200 nm) GaSb grains uniformly distributed on the matrix along with a few large grains (1–3 μm). The low electrical resistivity (ρ) of Ba0·2Co4Sb12 can be attributed to the +2 oxidation state of Ba. The increase in ρ of composites occurred due to the enhanced scattering of charge carriers at interfaces. No significant change in Seebeck coefficients was found in composites. The simultaneous effect of anharmonicity induced by Ba-filler in the voids and the enhanced interfaces between GaSb and the matrix reduced lattice thermal conductivity and brought about an improvement in zT from 0.75 to ~1.0 for (GaSb)0.4+Ba0·2Co4Sb12 at 773 K.",

keywords = "Bloch-gr{\"u}neisen relation, Callaway's equation, EBSD, Lattice thermal conductivity, Nanocomposite, Thermoelectrics",

author = "Sanyukta Ghosh and Gyan Shankar and Anirudha Karati and Gerda Rogl and Peter Rogl and Ernst Bauer and Murty, {B. S.} and Satyam Suwas and {Chandra Mallik}, Ramesh",

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doi = "10.1016/j.physb.2020.412440",

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T1 - Thermoelectric properties enhancement of Ba0·2Co4Sb12 through dispersion of GaSb inclusions

AU - Ghosh, Sanyukta

AU - Shankar, Gyan

AU - Karati, Anirudha

AU - Rogl, Gerda

AU - Rogl, Peter

AU - Bauer, Ernst

AU - Murty, B. S.

AU - Suwas, Satyam

AU - Chandra Mallik, Ramesh

PY - 2021/4/1

Y1 - 2021/4/1

N2 - The combined effects of Ba-filling the voids and GaSb nanophase incorporation in the matrix of Co4Sb12 have been studied for thermoelectric properties. High energy ball-milling was used to disperse GaSb in Ba0·2Co4Sb12. A slight off-stoichiometry between Co and Sb generated CoSb2 and CoSb phases. Electron back-scattered diffraction showed nanocrystalline (50–200 nm) GaSb grains uniformly distributed on the matrix along with a few large grains (1–3 μm). The low electrical resistivity (ρ) of Ba0·2Co4Sb12 can be attributed to the +2 oxidation state of Ba. The increase in ρ of composites occurred due to the enhanced scattering of charge carriers at interfaces. No significant change in Seebeck coefficients was found in composites. The simultaneous effect of anharmonicity induced by Ba-filler in the voids and the enhanced interfaces between GaSb and the matrix reduced lattice thermal conductivity and brought about an improvement in zT from 0.75 to ~1.0 for (GaSb)0.4+Ba0·2Co4Sb12 at 773 K.

AB - The combined effects of Ba-filling the voids and GaSb nanophase incorporation in the matrix of Co4Sb12 have been studied for thermoelectric properties. High energy ball-milling was used to disperse GaSb in Ba0·2Co4Sb12. A slight off-stoichiometry between Co and Sb generated CoSb2 and CoSb phases. Electron back-scattered diffraction showed nanocrystalline (50–200 nm) GaSb grains uniformly distributed on the matrix along with a few large grains (1–3 μm). The low electrical resistivity (ρ) of Ba0·2Co4Sb12 can be attributed to the +2 oxidation state of Ba. The increase in ρ of composites occurred due to the enhanced scattering of charge carriers at interfaces. No significant change in Seebeck coefficients was found in composites. The simultaneous effect of anharmonicity induced by Ba-filler in the voids and the enhanced interfaces between GaSb and the matrix reduced lattice thermal conductivity and brought about an improvement in zT from 0.75 to ~1.0 for (GaSb)0.4+Ba0·2Co4Sb12 at 773 K.

KW - Bloch-grüneisen relation

KW - Callaway's equation

KW - EBSD

KW - Lattice thermal conductivity

KW - Nanocomposite

KW - Thermoelectrics

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DO - 10.1016/j.physb.2020.412440

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JO - Physica B: Physics of Condensed Matter

JF - Physica B: Physics of Condensed Matter

M1 - 412440

ER -

Thermoelectric properties enhancement of Ba_0·2Co₄Sb₁₂ through dispersion of GaSb inclusions

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Keywords

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