Large-scale production of (GeTe) (AgSbTe2)100− (x=75, 80, 85, 90) with enhanced thermoelectric properties via gas-atomization and spark plasma sintering

Kim, Hyo-Seob; Dharmaiah, Peyala; Madavali, Babu; Ott, Ryan T.; Lee, Kap Ho; Hong, Soon‐Jik

doi:10.1016/j.actamat.2017.01.053

Cited by 48 publications

(22 citation statements)

References 32 publications

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“…The temperature dependence of the power factor, PF, of p‐type BiSbTe/ZnO composites are presented in Figure C. The power factor, PF, can be calculated from the obtained the Seebeck coefficient (α) and electrical conductivity (σ) as follows:…”

Section: Resultsmentioning

confidence: 99%

Investigation of microstructure and thermoelectric properties of p‐type BiSbTe/ZnO composites

Madavali

Lee

Kim

et al. 2017

Int J Applied Ceramic Tech

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In this research work, p-type BiSbTe/ZnO (2 wt%) nanocomposite powders were fabricated by high-energy ball milling at different milling times, and subsequently, powders were consolidated by spark plasma sintering at 673 K temperature. The existence of nanoinclusions was confirmed by SEM-EDS mapping. Vickers hardness values greatly improved due to reduction in grain size which prevents the crack propagation and dispersion strengthening mechanism. The decrease in carrier density, which plays a critical role in thermoelectrics, dramatically increases the Seebeck coefficient, and subsequently, decreases the electrical conductivity upon the dispersion of ZnO nanorods into the BiSbTe matrix. The thermal conductivity was noticeably reduced by~13% in BiSbTe/ZnO composites for 5-minute samples due to blocking of carriers/phonons at interfaces, and/or grain boundaries. The peak ZT of 0.92 was obtained for BiSbTe matrix, and 0.91 for BiSbTe/ZnO (5 minutes) composites at room temperatures. K E Y W O R D Sball milling, Bi 2 Te 3 alloys, nanocomposites, spark plasma sintering, thermoelectric materials 1 | INTRODUCTION Thermoelectric (TE) materials have been crucially used in renewable energy conversion technologies to overcome the energy crisis in the present world. The efficiency of TE materials can be defined by the dimensionless figure of merit, ZT = (a 2 r/K) T, where a, r, K, and T are the Seebeck coefficient, electrical conductivity, thermal conductivity, and absolute temperature, respectively. 1 In general, the temperature gradient develops an electrostatic potential, which is defined as the Seebeck coefficient (a = DV/DT for small DT). The Seebeck coefficient gradually decreases with carrier density, while the electrical conductivity increases. The thermal conductivity is proportional to the carrier density, which is contributed by both electrons and phonons. The ZT should be high, and at least unity (ZT ≥ 1) to maintain the device efficiency over 10%. 2,3 For ambient room temperature (RT) applications, bismuth telluride (Bi 2 Te 3 )-based alloys are much attracted due to their high-energy conversion thermoelectric efficient at RT. 3 So far, many researchers have studied TE properties and reported improved ZT values by forming composite structures and dispersion of nanoinclusions in bulk matrix thereby controlling the Seebeck coefficient and/or electrical conductivity via introduction of energy filtering effect that can filter the low energy electrons and allows only high energy (hot) electrons. 4,5 In addition, thermal conductivity is also reduced by phonon scattering at grain boundaries and/or interfaces between nanoinclusion and matrix. Hsu et al 6 reported enhanced TE properties in the AgPb m SbTe m+2 system with nanoscale inhomogeneous of Ag and Sb embedded in PbTe matrix that can dramatically decrease the thermal conductivity by increasing phonon scattering without affecting the electrical properties. Li et al 7 reported BiSbTe-based nanocomposites with high ZT values through dispersion of SiC nanopartic...

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Section: Resultsmentioning

confidence: 99%

Investigation of microstructure and thermoelectric properties of p‐type BiSbTe/ZnO composites

Madavali

Lee

Kim

et al. 2017

Int J Applied Ceramic Tech

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“…Moreover, GeTe also undergoes a phase transition from rhombohedral phase at low temperature to cubic phase at high temperature, ,, which can also influence the TE performance. Thus, to enhance the TE performance of the GeTe-based materials, carrier density modulation and phase structure tuning strategies are widely performed by doping and alloying with other elements such as Pb, , Pb–Se, ,, Pb–Bi, Pb–Sb, , Sb, Sb–Se, , Sb–Bi, Se–S, Bi, Bi–Cu, Bi–Cd, , Bi–Mn, In, and In–Sb, as well as with other compounds such as AgSbTe 2 , Bi 2 Te 3 , , Sb 2 Te 3 , ,, and MnTe . Band engineering mechanisms such as band convergence ,,, and resonant levels , have been put forward to understand the high PF in the GeTe-based alloys, and point defect scattering is the most proposed mechanism to explain the reduction of κ lat in the GeTe-based alloys. , …”

Section: Introductionmentioning

confidence: 99%

Stacking Fault-Induced Minimized Lattice Thermal Conductivity in the High-Performance GeTe-Based Thermoelectric Materials upon Bi₂Te₃ Alloying

Xie

Zhang

et al. 2019

ACS Appl. Mater. Interfaces

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Materials with low lattice thermal conductivity (κlat) are crucial for the applications of thermal insulation and thermoelectric (TE) energy conversion. Stacking fault (SF)-induced phonon scattering within interfaces has been put forward theoretically by Klemens in 1950s. However, unlike other traditional defects such as point defects, grain boundaries, and dislocations, the role of SF for reducing κlat remains poorly understood and is yet to be revealed experimentally. The layered Bi2Te3 with a van der Waals gap shows different stacking structures than the nonlayered GeTe, which is used to introduce SFs into the GeTe-based alloys in this work. On the basis of the experimental and theoretical modeling results, this paper reveals the significant contribution of SF phonon scattering for minimizing the κlat. Besides the achieved extremely low κlat (∼0.39 W m–1 K–1 at 573 K), optimized carrier density and band convergence are also realized in the GeTe-based alloys upon Bi2Te3 alloying, leading to a significant high TE figure of merit ZT > 2 at 773 K and an averaged ZT > 1.4 within 300–773 K. This SF engineering strategy provides a different avenue to reduce the κlat for enhancing the performance of thermal insulation and TE materials.

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“…In addition to reducing lattice thermal conductivity and improving thermoelectric performance by alloying other elements in the same column of the periodic table, manipulating intrinsic defects also works. This idea has been widely identified in alloys of IV–VI compounds such as PbTe–AgSbTe 2 (LAST), − GeTe–AgSbTe 2 (TAGS), − and SnTe–AgSbTe 2 . − − To date, many IV–VI compounds have achieved excellent TE performance by alloying with I–V–VI 2 family members like Na(Sb,Bi)Te 2 , which are all distinguished by their intrinsically ultralow lattice thermal conductivity due to the presence of lone pair electrons, causing broad concern in the thermoelectric academic circle. − For instance, GeTe alloying with CuSbSe 2 results in phase transition and carrier concentration optimization, giving rise to a zT max of 1.65 at 630 K, and maximum zT values of ∼0.5 at 300 K and ∼1.4 at 723 K and an average zT of ∼0.94 at 300–723 K are achieved in n-type PbTe–CuSbSe 2 due to the hierarchical structures of nanoprecipitates and interstitials, which can well balance the phonon and carrier transport, while NaPb m SbTe m +2 presented lower lattice thermal conductivity, with zT as high as 1.60 at 673 K …”

Section: Introductionmentioning

confidence: 99%

Multiple Effects Promoting the Thermoelectric Performance of SnTe by Alloying with CuSbTe₂ and CuBiTe₂

Wang

et al. 2021

ACS Appl. Mater. Interfaces

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In a SnTe-based thermoelectric material, the naturally high hole concentration caused by cation vacancies and high total thermal conductivity seriously hinder its thermoelectric performance. A recent work shows that alloying SnTe with other compounds from the I−V−VI 2 family (I = Ag, Na; V = Sb, Bi; VI = Te) can be considered an effective strategy to boost the figure of merit efficiently via the synergy of manipulating hole concentration and lowering lattice thermal conductivity. Herein, we present a markedly enhanced thermoelectric performance in p-type SnTe through CuPnTe 2 (Pn = Sb, Bi) alloying. Moreover, we found that the alloying with both CuSbTe 2 and CuBiTe 2 can facilitate the valence band convergence of SnTe, but their relative influence is different. Interestingly, compared to CuBiTe 2 , alloying with CuSbTe 2 increases the carrier concentration of SnTe, which suppresses the bipolar effect. Ultimately, under the positive effect of valence band convergence, increased vacancy concentration, and decreased lattice thermal conductivity, compounds with a nominal composition of (SnTe) 0.90 (CuSbTe 2 ) 0.10 attains a peak zT of ∼1.26 at 823 K. In contrast, the thermoelectric performance of (SnTe) 1−x (CuBiTe 2 ) x is restricted by the reduced carrier concentration and diminished band gap, showing only a humble maximum zT value of ∼0.91 at 823 K in the sample with a nominal composition of (SnTe) 0.96 (CuBiTe 2 ) 0.04 . These results demonstrate the multiple effects on thermoelectric transport during the formation of complex solid solutions.

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Large-scale production of (GeTe) (AgSbTe2)100− (x=75, 80, 85, 90) with enhanced thermoelectric properties via gas-atomization and spark plasma sintering

Cited by 48 publications

References 32 publications

Investigation of microstructure and thermoelectric properties of p‐type BiSbTe/ZnO composites

Investigation of microstructure and thermoelectric properties of p‐type BiSbTe/ZnO composites

Stacking Fault-Induced Minimized Lattice Thermal Conductivity in the High-Performance GeTe-Based Thermoelectric Materials upon Bi₂Te₃ Alloying

Multiple Effects Promoting the Thermoelectric Performance of SnTe by Alloying with CuSbTe₂ and CuBiTe₂

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Large-scale production of (GeTe) (AgSbTe2)100− (x=75, 80, 85, 90) with enhanced thermoelectric properties via gas-atomization and spark plasma sintering

Cited by 48 publications

References 32 publications

Investigation of microstructure and thermoelectric properties of p‐type BiSbTe/ZnO composites

Investigation of microstructure and thermoelectric properties of p‐type BiSbTe/ZnO composites

Stacking Fault-Induced Minimized Lattice Thermal Conductivity in the High-Performance GeTe-Based Thermoelectric Materials upon Bi2Te3 Alloying

Multiple Effects Promoting the Thermoelectric Performance of SnTe by Alloying with CuSbTe2 and CuBiTe2

Contact Info

Product

Resources

About

Stacking Fault-Induced Minimized Lattice Thermal Conductivity in the High-Performance GeTe-Based Thermoelectric Materials upon Bi₂Te₃ Alloying

Multiple Effects Promoting the Thermoelectric Performance of SnTe by Alloying with CuSbTe₂ and CuBiTe₂