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

Chen, Xiaoxi1; Wu, Haijun2; Cui, Juan3,4; Xiao, Yu5; Zhang, Yang2; He, Jiaqing4; Chen, Yue3; Cao, Jian1; Cai, Wei1; Pennycook, Stephen J.2; Liu, Zihang1; Zhao, Li-Dong5; Sui, Jiehe1

2018-10

10.1016/j.nanoen.2018.07.059

Nano Energy   影响因子和分区

2211-2855

2211-3282

Zintl 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 similar to 1.85 at 723 K and an average ZT similar to 1.25 (from 300 K to 723 K), which are the highest ever reported in any n-type thermoelectric material.

N-type Zintl Mg3Sb2 High band degeneracy Tuning carrier scattering mechanism Hierarchical microstructure

SCI ; EI

英语

其他

Ministry of Education, Singapore under its Tier 2 Grant[MOE2017-T2-1-129]

Chemistry ; Science & Technology - Other Topics ; Materials Science ; Physics

Chemistry, Physical ; Nanoscience & Nanotechnology ; Materials Science, Multidisciplinary ; Physics, Applied

WOS:000444859700025

ELSEVIER SCIENCE BV

20183205653309

Antimony compounds ; Bismuth compounds ; Electron scattering ; Grain boundaries ; High resolution transmission electron microscopy ; Impurities ; Ionization ; Manganese ; Microstructure ; Nanotechnology ; Scanning electron microscopy ; Temperature ; Thermal conductivity ; Thermoelectricity ; Transmission electron microscopy

Manganese and Alloys:543.2 ; Thermodynamics:641.1 ; Electricity: Basic Concepts and Phenomena:701.1 ; Optical Devices and Systems:741.3 ; Nanotechnology:761 ; Chemical Reactions:802.2 ; Materials Science:951

Web of Science

1.Harbin Inst Technol, State Key Lab Adv Welding & Joining, Harbin 150001, Heilongjiang, Peoples R China
2.Natl Univ Singapore, Dept Mat Sci & Engn, Singapore 117575, Singapore
3.Univ Hong Kong, Dept Mech Engn, Pokfulam Rd, Hong Kong, Hong Kong, Peoples R China
4.Southern Univ Sci & Technol, Dept Phys, Shenzhen 518055, Peoples R China
5.Beihang Univ, Sch Mat Sci & Engn, Beijing 100191, Peoples R China

Chen, Xiaoxi,Wu, Haijun,Cui, Juan,et al. Extraordinary thermoelectric performance in n-type manganese doped Mg3Sb2 Zintl: High band degeneracy, tuned carrier scattering mechanism and hierarchical microstructure[J]. Nano Energy,2018,52:246-255.

Chen, Xiaoxi.,Wu, Haijun.,Cui, Juan.,Xiao, Yu.,Zhang, Yang.,...&Sui, Jiehe.(2018).Extraordinary thermoelectric performance in n-type manganese doped Mg3Sb2 Zintl: High band degeneracy, tuned carrier scattering mechanism and hierarchical microstructure.Nano Energy,52,246-255.

Chen, Xiaoxi,et al."Extraordinary thermoelectric performance in n-type manganese doped Mg3Sb2 Zintl: High band degeneracy, tuned carrier scattering mechanism and hierarchical microstructure".Nano Energy 52(2018):246-255.