Microstructural iterative reconstruction toward excellent thermoelectric performance in MnTe

Earth-abundant manganese telluride (MnTe) with a hexagonal structure has shown significant thermoelectric conversion potential; however, the drawbacks of low carrier concentration and low mobility have limited its application. Herein, we constructed a type of layer structure by fabricating polycryst...

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Published inEnergy & environmental science Vol. 16; no. 9; pp. 3743 - 3752
Main Authors Luo, Yiyuan, Wang, Jinghan, Yang, Jianmin, Mao, Dasha, Cui, Juan, Jia, Baohai, Liu, Xusheng, Nielsch, Kornelius, Xu, Xiao, He, Jiaqing
Format Journal Article
LanguageEnglish
Published Cambridge Royal Society of Chemistry 13.09.2023
Subjects
Carrier density
Germanium
Hole density
Manganese
Mobility
Scattering
Tellurides
Temperature gradients
Thermal conductivity
Thermoelectric generators
Thermoelectricity
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Summary:Earth-abundant manganese telluride (MnTe) with a hexagonal structure has shown significant thermoelectric conversion potential; however, the drawbacks of low carrier concentration and low mobility have limited its application. Herein, we constructed a type of layer structure by fabricating polycrystalline MnSb 2 Te 4 , increasing the hole density by 100 times. The introduced van der Waals gaps effectively enhanced the phonon scattering, further suppressing the intrinsic low thermal conductivity. The reduced hole concentration in the Ge-doped MnSb 2 Te 4 -based specimens, verified by both theoretical calculations and experimental characterization studies, was unexpectedly found to enhance mobility by reducing the intervalley scattering of carriers, resulting in a record high average ZT value of 0.71 from 300 K to 823 K and an excellent peak ZT value of 1.3 at 823 K. Hence, an Mn 0.96 Ge 0.04 Sb 2 Te 4 -based single stage generating module was successfully assembled with a competitive performance of 0.81 W (0.45 W cm 2 ) and 4.6% over a temperature gradient of 480 K. This tailored investigation created an outstanding MnTe-based specimen, which could serve as a candidate for application in thermoelectric generators. A pioneering structural optimization is offered to boost the carrier concentration and mobility in a MnTe-based specimen for excellent thermoelectric performance.
Bibliography:Electronic supplementary information (ESI) available: Experimental sections and calculating models. The rebuilt phase diagram (Fig. S1), the fracture appearance (Fig. S2), the thermoelectric performance (Fig. S3), the low magnification EDS analysis (Fig. S4), the calculated ELF and phonon dispersion (Fig. S5), the XRD pattern (Fig. S6), the calculated band structures (Fig. S7), the simulated Seebeck coefficients (Fig. S8), the thermal transport properties (Fig. S9), the performance of legs (Fig. S10), the thicknesses of legs (Fig. S11), and the performance of the second module (Fig. S12). The mass density of all samples (Table S1) and the sound velocity of MnTe-based samples (Table S2). See DOI
https://doi.org/10.1039/d3ee01902k
ISSN:1754-5692
1754-5706
DOI:10.1039/d3ee01902k