High Thermoelectric Performance of SnTe from the Disproportionation of SnO

doi:10.15541/jim20180288

Abstract

Abstract:

PbTe-based compositions are considered as excellent thermoelectric materials for the mid-temperature. However, the toxicity of lead limits its wide application. SnTe compounds, an analogue of PbTe, has attracted much attention. However, its ultrahigh carrier concentration and the large lattice thermal conductivity leads to a low ZT value of SnTe. In this work,thethermoelectric performance of SnTe is synergistically enhanced by introduction of Sn and SnO₂ from the disproportionation of SnO in the process of the hot press sintering. On the one hand, Sn can compensate the Sn vacancies and decrease the carrier concentration of SnTe, leading to a simultaneous enhancement on resistivity and the Seebeck coefficient. For instance, compared with the pristine SnTe, resistivity and the Seebeck coefficient increases from 6.5μΩ•m to 10.5μΩ•m and from 105μV•K^-1to 146μV•K^-1,respectively, for the sample of SnTe-6mol% SnO at 873K. On the other hand, in-situ generated SnO₂ nanoparticles are dispersedly distributed on the grain boundaries, leading to the multiscale phonon scattering and the reduced lattice thermal conductivity. The minimum lattice thermal conductivity value is 0.6 W•m^-1•K^-1 for the sample SnTe-6mol% SnO at 873K, which is ~33% reduction compared with that of the pristine SnTe. As a result, the maximum ZT value of 0.96 (~100% enhancement, compared with that of the pristine SnTe) at 873K is achieved for the sample SnTe-6mol% SnO.

Key words: SnTe, disproportionation, thermoelectric performance

CLC Number:

TB34

HU Hui-Shan, YANG Jun-You, XIN Jin-Wu, LI Si-Hui, JIANG Qing-Hui. High Thermoelectric Performance of SnTe from the Disproportionation of SnO[J]. Journal of Inorganic Materials, 2019, 34(3): 315-320.

Figures/Tables 8

Fig. 1 DTA curves of SnO powder and hot pressed SnTe-6mol%SnO

Fig.2 XRD patterns of SnTe-xmol%SnO (x=0, 2, 4, 6)samples(a) and high angle peak position comparison between different samples(b)

Fig.3 High magnification cross-sectional FESEM image of (a) SnTe and (b) SnTe-6mol%SnO sample, (c) EDS composition analysis results for the spot marked in Fig.3(b), low magnification cross-sectional FESEM image of SnTe-6mol%SnO sample (d)

Fig.4 Temperature dependence of (a) electrical resisitivity and (b) Seebeck coefficient of SnTe-ymol%SnO2 (y=0, 1, 2, 3) samples

Fig.5 Temperature dependence of (a)electrical resisitivity, (b) Seebeck coefficient, (c) power factor of SnTe-xmol%SnO2(x=0, 2,4,6) samples, (d) carrier concentration (n) and carrier mobility (m) at room temperature of the samples

Fig.6 Temperature dependence of (a) thermal conductivity, (b) carrier thermal conductivity and (c) lattice thermal conductivity of SnTe-xmol%SnO samples

Fig.7 Temperature dependence of ZT values of SnTe-xmol%SnOsamples

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