Title: Expression of interfacial Seebeck coefficient through grain boundary engineering with multi-layer graphene nanoplatelets

Abstract

Energy filtering has been a long-sought strategy to enhance a thermoelectric material's figure of merit zT through improving its power factor. Here we show a composite of multi-layer graphene nanoplatelets (GNP) and n-type Mg₃Sb₂ leads to the expression of an energy filtering like effect demonstrated by an increase in the material's Seebeck coefficient and maximum power factor, without impact on the material's carrier concentration. We analyse these findings from the perspective of a heterogeneous material consisting of grain and grain boundary phases, instead of a more traditional and common analysis that assumes a homogeneously transporting medium. An important implication of this treatment is that it leads to the development of an interfacial Seebeck coefficient term, which can explain the observed increase in the material's Seebeck coefficient. The contribution of this interfacial Seebeck coefficient to the overall Seebeck coefficient is determined by the relative temperature drop across the grain boundary region compared to that of the bulk material. In Te doped Mg₃Sb₂ we show the introduction of GNP increases the interfacial thermal resistance of grain boundaries, enhancing the contribution of the interfacial Seebeck coefficient arising from grain boundaries to the overall Seebeck coefficient. Without significant detriment to the electrical conductivity thismore » effect results in a net increase in maximum power factor. This increased interfacial thermal resistance also leads to the synergistic reduction of the total thermal conductivity. As a result, we enhance zT of the Mg₃Sb₂ to a peak value of 1.7 near 750 K. Considering the two-dimensional nature of the grain boundary interface, this grain boundary engineering strategy could be applied to a few thermoelectric systems utilizing various two-dimensional nanomaterials.« less

Authors:

Lin, Yue  ^[1];

• Search DOE PAGES for author "Lin, Yue"
• Search DOE PAGES for ORCID "0000-0001-9196-9180"

Wood, Maxwell  ^[2];

• Search DOE PAGES for author "Wood, Maxwell"
• Search DOE PAGES for ORCID "0000-0003-2758-6155"

Imasato, Kazuki  ^[2];

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• Search DOE PAGES for ORCID "0000-0001-7294-1780"

Kuo, Jimmy Jiahong  ^[2];

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• Search DOE PAGES for ORCID "0000-0002-3434-1984"

Lam, David  ^[2];

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• Search DOE PAGES for ORCID "0000-0003-4264-0033"

Mortazavi, Anna N. ^[3]; Slade, Tyler J.  ^[2];

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• Search DOE PAGES for ORCID "0000-0001-6751-4303"

Hodge, Stephen A.  ^[4];

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• Search DOE PAGES for ORCID "0000-0002-5679-6568"

Xi, Kai  ^[5];

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• Search DOE PAGES for ORCID "0000-0003-0508-7910"

Kanatzidis, Mercouri G.  ^[2];

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• Search DOE PAGES for ORCID "0000-0003-2037-4168"

Clarke, David R. ^[6]; Hersam, Mark C.  ^[2];

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• Search DOE PAGES for ORCID "0000-0003-4120-1426"

Snyder, G. Jeffrey  ^[2]

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• Search DOE PAGES for ORCID "0000-0003-1414-8682"

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+ Show Author Affiliations

1. Northwestern Univ., Evanston, IL (United States); Univ. of Cambridge (United Kingdom)
2. Northwestern Univ., Evanston, IL (United States)
3. Harvard Univ., Cambridge, MA (United States); Monash Univ., Clayton, VIC (Australia)
4. Versarien Plc, Cheltenham (United Kingdom)
5. Univ. of Cambridge (United Kingdom)
6. Harvard Univ., Cambridge, MA (United States)

Publication Date:

Thu Sep 24 00:00:00 EDT 2020

Research Org.:

Northwestern Univ., Evanston, IL (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1777417

Grant/Contract Number:  

SC0014520

Resource Type:

Accepted Manuscript

Journal Name:

Energy & Environmental Science

Additional Journal Information:

Journal Volume: 13; Journal Issue: 11; Journal ID: ISSN 1754-5692

Publisher:

Royal Society of Chemistry

Country of Publication:

United States

Language:

English

Subject:

42 ENGINEERING