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Article: Extraordinary thermoelectric performance in n-type manganese doped Mg3Sb2 Zintl: High band degeneracy, tuned carrier scattering mechanism and hierarchical microstructure

TitleExtraordinary thermoelectric performance in n-type manganese doped Mg3Sb2 Zintl: High band degeneracy, tuned carrier scattering mechanism and hierarchical microstructure
Authors
KeywordsN-type Zintl
Mg3Sb2
High band degeneracy
Tuning carrier scattering mechanism
Hierarchical microstructure
Issue Date2018
PublisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/issn/22112855
Citation
Nano Energy, 2018, v. 52, p. 246-255 How to Cite?
AbstractZintl phases are ideal candidates for thermoelectric applications due to their rich chemistry and structural complexity. However, the persistent p-type conduction due to intrinsic defects strongly restricts their practical applications. Recently, several typical n-type Zintl materials have been designed, where Te-doped Mg3Sb1.5Bi0.5 as the most promising. To enhance its overall thermoelectric performance, we introduce Mn to synergistically optimize the electrical and thermal transport properties. Both experimental and computational results demonstrate that multiple conduction bands with high band degeneracy are responsible for the enhanced Seebeck coefficient. Mn doping on Mg sites changes the low-temperature carrier scattering mechanism from ionized impurity scattering to mixed scattering with acoustic phonons and ionized impurities, resulting in a significant enhancement of carrier mobility and therefore power factor. Simultaneously, the total thermal conductivity is observably reduced after Mn doping. We employed aberration-corrected scanning transmission electron microscopy (Cs-corrected STEM) to thoroughly investigate its hierarchical microstructure, including sub-micron grains, nanoscale Bi precipitates segregated at grain boundaries, nanoscale endotaxial Bi-rich precipitates within the Mg3Sb2 based matrix, as well as the resulting strain fields around these defects. The synergistic optimization of electrical and thermal transport contributes to extraordinary performance, namely a peak ZT ~ 1.85 at 723 K and an average ZT ~ 1.25 (from 300 K to 723 K), which are the highest ever reported in any n-type thermoelectric material.
Persistent Identifierhttp://hdl.handle.net/10722/272237
ISSN
2017 Impact Factor: 13.12
2015 SCImago Journal Rankings: 4.169
ISI Accession Number ID

 

DC FieldValueLanguage
dc.contributor.authorChen, X-
dc.contributor.authorWu, H-
dc.contributor.authorCui, J-
dc.contributor.authorXiao, Y-
dc.contributor.authorZhang, Y-
dc.contributor.authorHe, J-
dc.contributor.authorChen, Y-
dc.contributor.authorCao, J-
dc.contributor.authorCai, W-
dc.contributor.authorPennycook, SJ-
dc.contributor.authorLiu, Z-
dc.contributor.authorZhao, LD-
dc.contributor.authorSui, J-
dc.date.accessioned2019-07-20T10:38:22Z-
dc.date.available2019-07-20T10:38:22Z-
dc.date.issued2018-
dc.identifier.citationNano Energy, 2018, v. 52, p. 246-255-
dc.identifier.issn2211-2855-
dc.identifier.urihttp://hdl.handle.net/10722/272237-
dc.description.abstractZintl phases are ideal candidates for thermoelectric applications due to their rich chemistry and structural complexity. However, the persistent p-type conduction due to intrinsic defects strongly restricts their practical applications. Recently, several typical n-type Zintl materials have been designed, where Te-doped Mg3Sb1.5Bi0.5 as the most promising. To enhance its overall thermoelectric performance, we introduce Mn to synergistically optimize the electrical and thermal transport properties. Both experimental and computational results demonstrate that multiple conduction bands with high band degeneracy are responsible for the enhanced Seebeck coefficient. Mn doping on Mg sites changes the low-temperature carrier scattering mechanism from ionized impurity scattering to mixed scattering with acoustic phonons and ionized impurities, resulting in a significant enhancement of carrier mobility and therefore power factor. Simultaneously, the total thermal conductivity is observably reduced after Mn doping. We employed aberration-corrected scanning transmission electron microscopy (Cs-corrected STEM) to thoroughly investigate its hierarchical microstructure, including sub-micron grains, nanoscale Bi precipitates segregated at grain boundaries, nanoscale endotaxial Bi-rich precipitates within the Mg3Sb2 based matrix, as well as the resulting strain fields around these defects. The synergistic optimization of electrical and thermal transport contributes to extraordinary performance, namely a peak ZT ~ 1.85 at 723 K and an average ZT ~ 1.25 (from 300 K to 723 K), which are the highest ever reported in any n-type thermoelectric material.-
dc.languageeng-
dc.publisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/issn/22112855-
dc.relation.ispartofNano Energy-
dc.subjectN-type Zintl-
dc.subjectMg3Sb2-
dc.subjectHigh band degeneracy-
dc.subjectTuning carrier scattering mechanism-
dc.subjectHierarchical microstructure-
dc.titleExtraordinary thermoelectric performance in n-type manganese doped Mg3Sb2 Zintl: High band degeneracy, tuned carrier scattering mechanism and hierarchical microstructure-
dc.typeArticle-
dc.identifier.emailChen, Y: yuechen@hku.hk-
dc.identifier.authorityChen, Y=rp01925-
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1016/j.nanoen.2018.07.059-
dc.identifier.scopuseid_2-s2.0-85050868254-
dc.identifier.hkuros298963-
dc.identifier.volume52-
dc.identifier.spage246-
dc.identifier.epage255-
dc.identifier.isiWOS:000444859700025-
dc.publisher.placeNetherlands-

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