Impurity-free, mechanical doping for the reproducible fabrication of the reliable n-type Bi2Te3-based thermoelectric alloys

Jung, Sung Jin; Lee, Byeong Hyeon; Kim, Byung Kyu; Lim, Sang Soon; Kim, Seong Keun; Kim, Dong Ik; Won, Sung Ok; Park, Hyung Ho; Kim, Jin Sang; Baek, Seung Hyub

doi:10.1016/j.actamat.2018.02.061

Cited by 26 publications

(5 citation statements)

References 40 publications

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“…Compared with the n-type ZM ingots, the powder-metallurgy-derived n-type Bi 2 Te 3– y Se y samples can generally have lower κ lat , ,, but they also usually have higher carrier concentration due to the strong donor-like effect caused by the hot pressing or sintering process, , making the optimization of carrier concentration a big challenge for powder-metallurgy-derived n-type Bi 2 Te 3 based alloys. Moreover, reducing the higher carrier concentration from the donor-like effect is also important for shifting the best thermoelectric performance to room temperature. , Strategies like solution-processed nanostructuring, − compositional control (such as doping Cu, − Ag, , Ge, K) and mechanical deformation (mostly hot deformation, HD) ,,,,,− have been reported to manipulate the carrier concentration and other thermoelectric properties of the n-type Bi 2 Te 3 -based compounds. Various HD processes have been widely developed to optimize the carrier concentration and to reduce κ lat for enhancing the ZT, ,,,,,− and a state-of-the-art ZT of ∼1.3 at 450 K in the n-type Bi 2 Te 3– y Se y samples is realized by an HD approach .…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, reducing the higher carrier concentration from the donor-like effect is also important for shifting the best thermoelectric performance to room temperature. , Strategies like solution-processed nanostructuring, − compositional control (such as doping Cu, − Ag, , Ge, K) and mechanical deformation (mostly hot deformation, HD) ,,,,,− have been reported to manipulate the carrier concentration and other thermoelectric properties of the n-type Bi 2 Te 3 -based compounds. Various HD processes have been widely developed to optimize the carrier concentration and to reduce κ lat for enhancing the ZT, ,,,,,− and a state-of-the-art ZT of ∼1.3 at 450 K in the n-type Bi 2 Te 3– y Se y samples is realized by an HD approach . However, the HD process needs multiple sintering or pressing processes and changing the size of graphite die in each sintering or pressing process, ,, which make the preparation process more complicated and unfavorable for the large-scale production of Bi 2 Te 3 -based alloys.…”

Section: Introductionmentioning

confidence: 99%

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Simultaneous Enhancement of the Thermoelectric and Mechanical Performance in One-Step Sintered n-Type Bi₂Te₃-Based Alloys via a Facile MgB₂ Doping Strategy

Chen

et al. 2019

ACS Appl. Mater. Interfaces

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The Bi 2 Te 3 -based alloys have been commercialized for the applications of energy harvesting and refrigeration for decades. However, the commercial Bi 2 Te 3 -based alloys produced by the zone-melting (ZM) method usually show poor mechanical strength and crack problems as well as the sluggish figure of merit ZT, especially for the less-progressed n-type samples. In this work, we have simultaneously enhanced the thermoelectric and mechanical performance of the one-step spark plasma sintering (SPS)-derived n-type Bi 2 Te 2.7 Se 0.3 alloys just by doping a small amount of superconducting material MgB 2 where Mg and B atoms can play significant roles in carrier density optimization and hardness enhancement. Besides the optimization of carrier density, the MgB 2 doping can also increase the carrier mobility but decrease the lattice and bipolar thermal conductivity, leading to a peak ZT of 0.96 at 325 K and an average ZT of 0.88 within 300−500 K in the 0.5% MgB 2 -doped Bi 2 Te 2.7 Se 0.3 (BTSMB) alloys. The peak ZT and average ZT of our optimized BTSMB samples are comparable and higher than those of the state-of-the-art commercial ZM ingot. Moreover, the optimized BTSMB sample also exhibits almost 70% enhancement in hardness compared with the ZM ingot. Our results demonstrate the great potential of the MgB 2 doping strategy for mass production of SPS-derived Bi 2 Te 3 -based alloys in one-step sintering.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Simultaneous Enhancement of the Thermoelectric and Mechanical Performance in One-Step Sintered n-Type Bi₂Te₃-Based Alloys via a Facile MgB₂ Doping Strategy

Chen

et al. 2019

ACS Appl. Mater. Interfaces

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“…These observations suggest that electronic and other functional properties of the material can be strongly impacted by the core structure of dislocations present at the van der Waals gap. The motion and interaction of dislocations under thermomechanical processing can also strongly alter the carrier concentrations, which directly affects properties such as the electrical resistivity and thermopower [21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Unraveling the dislocation core structure at a van der Waals gap in bismuth telluride

et al. 2019

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Tetradymite-structured chalcogenides such as bismuth telluride (Bi 2 Te 3 ) are of significant interest for thermoelectric energy conversion and as topological insulators. Dislocations play a critical role during synthesis and processing of such materials and can strongly affect their functional properties. The dislocations between quintuple layers present special interest since their core structure is controlled by the van der Waals interactions between the layers. In this work, using atomic-resolution electron microscopy, we resolve the basal dislocation core structure in Bi 2 Te 3 , quantifying the disregistry of the atomic planes across the core. We show that, despite the existence of a stable stacking fault in the basal plane gamma surface, the dislocation core spreading is mainly due to the weak bonding between the layers, which leads to a small energy penalty for layer sliding parallel to the van der Waals gap. Calculations within a semidiscrete variational Peierls-Nabarro model informed by first-principles calculations support our experimental findings.

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“…These phenomena are more prominent for undoped samples ,,, and have been the major mechanism to modify the properties of some TE materials such as Bi 2 Te 3. , …”

Section: Resultsmentioning

confidence: 99%

Reduced Lattice Thermal Conductivity for Half-Heusler ZrNiSn through Cryogenic Mechanical Alloying

Bahrami

Ying

Wolff

et al. 2021

ACS Appl. Mater. Interfaces

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The ZrNiSn-based half-Heusler compounds are promising for thermoelectric applications in the mid-to-high temperature range. However, their thermoelectric performance was greatly limited due to the remaining high thermal conductivity, especially the lattice thermal conductivity. Herein, we report the synthesis of pristine half-Heusler ZrNiSn through direct mechanical alloying at a liquid nitrogen temperature (i.e., cryomilling) followed by spark plasma sintering. It is shown that the onset sintering temperature is greatly reduced for the cryomilled powders with a high density. A reduced thermal conductivity is subsequently realized from room temperature to 700 °C in the cryomilled samples than the one that was differently prepared (from 7.3 to 4.5 W/m K at room temperature). The pronounced reduction in thermal conductivity of ZrNiSn yields a maximum zT of ∼0.65 at 700 °C. Our study shows the possibility of cryomilling in advancing the thermoelectric performance through enhanced phonon scattering.

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Impurity-free, mechanical doping for the reproducible fabrication of the reliable n-type Bi2Te3-based thermoelectric alloys

Cited by 26 publications

References 40 publications

Simultaneous Enhancement of the Thermoelectric and Mechanical Performance in One-Step Sintered n-Type Bi₂Te₃-Based Alloys via a Facile MgB₂ Doping Strategy

Simultaneous Enhancement of the Thermoelectric and Mechanical Performance in One-Step Sintered n-Type Bi₂Te₃-Based Alloys via a Facile MgB₂ Doping Strategy

Unraveling the dislocation core structure at a van der Waals gap in bismuth telluride

Reduced Lattice Thermal Conductivity for Half-Heusler ZrNiSn through Cryogenic Mechanical Alloying

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Impurity-free, mechanical doping for the reproducible fabrication of the reliable n-type Bi2Te3-based thermoelectric alloys

Cited by 26 publications

References 40 publications

Simultaneous Enhancement of the Thermoelectric and Mechanical Performance in One-Step Sintered n-Type Bi2Te3-Based Alloys via a Facile MgB2 Doping Strategy

Simultaneous Enhancement of the Thermoelectric and Mechanical Performance in One-Step Sintered n-Type Bi2Te3-Based Alloys via a Facile MgB2 Doping Strategy

Unraveling the dislocation core structure at a van der Waals gap in bismuth telluride

Reduced Lattice Thermal Conductivity for Half-Heusler ZrNiSn through Cryogenic Mechanical Alloying

Contact Info

Product

Resources

About

Simultaneous Enhancement of the Thermoelectric and Mechanical Performance in One-Step Sintered n-Type Bi₂Te₃-Based Alloys via a Facile MgB₂ Doping Strategy

Simultaneous Enhancement of the Thermoelectric and Mechanical Performance in One-Step Sintered n-Type Bi₂Te₃-Based Alloys via a Facile MgB₂ Doping Strategy