Realizing a stable high thermoelectric zT ∼ 2 over a broad temperature range in Ge1−x−yGaxSbyTe via band engineering and hybrid flash-SPS processing

Srinivasan, Bhuvanesh; Gellé, Alain; Gucci, Francesco; Boussard‐Plédel, Catherine; Fontaine, Bruno La; Gautier, Régis; Halet, Jean‐François; Reece, Michael J.; Bureau, Bruno

doi:10.1039/c8qi00703a

Cited by 84 publications

(88 citation statements)

References 75 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Table 4 compares different GeTe‐based thermoelectric materials synthesized by different method, including high‐vacuum and high‐temperature melting [ 80,127,128,140,144–147 ] or solid‐state reaction [ 148,149 ] method. The high temperature can secure sufficient reaction of precursors to form high‐purity and composition‐homogeneous solid solutions.…”

Section: Materials Preparationmentioning

confidence: 99%

See 1 more Smart Citation

High‐Performance GeTe‐Based Thermoelectrics: from Materials to Devices

Liu

Wang

et al. 2020

Advanced Energy Materials

185

128

View full text Add to dashboard Cite

m ), [52] enlarging band degeneracy (N V ), [43] and introducing resonant energy levels, [26] can also tune n p effectively. Taking Ge 1−x−y Sb x Zn y Te as an example, Zn doping can reduce the energy offset (ΔE) between L and Σ point. [52] The minimization of thermal transport properties is mainly achieved through suppressing the electrical property-independent κ l . [53][54][55][56][57] Thermoelectric materials with High-performance GeTe-based thermoelectrics have been recently attracting growing research interest. Here, an overview is presented of the structural and electronic band characteristics of GeTe. Intrinsically, compared to lowtemperature rhombohedral GeTe, the high-symmetry and high-temperature cubic GeTe has a low energy offset between L and Σ points of the valence band, the reduced direct bandgap and phonon group velocity, and as a result, high thermoelectric performance. Moreover, their thermoelectric performance can be effectively enhanced through either carrier concentration optimization, band structure engineering (bandgap reduction, band degeneracy, and resonant state engineering), or restrained lattice thermal conductivity (phonon velocity reduction or phonon scattering). Consequently, the dimensionless figure of merit, ZT values, of GeTe-based thermoelectric materials can be higher than 2. The mechanical and thermal stabilities of GeTe-based thermoelectrics are highlighted, and it is found that they are suitable for practical thermoelectric applications except for their high cost. Finally, it is recognized that the performance of GeTe-based materials can be further enhanced through synergistic effects. Additionally, proper material selection and module design can further boost the energy conversion efficiency of GeTe-based thermoelectrics.

show abstract

Section: Materials Preparationmentioning

confidence: 99%

“…[ 149 ] Through large current heating, spark plasma sintering (SPS) can sinter GeTe powders into pellets within several minutes, which can refrain the crystal growth and maintain the structural features. [ 52,146 ]…”

Section: Materials Preparationmentioning

confidence: 99%

High‐Performance GeTe‐Based Thermoelectrics: from Materials to Devices

Liu

Wang

et al. 2020

Advanced Energy Materials

185

128

View full text Add to dashboard Cite

show abstract

“…Sources of low temperature waste heat mostly include heat loss from industrial products, equipment and processes, and heat discharged from combustion processes. Therefore, using heat exchangers to recover the low temperature waste heat would be the major approach rather than the thermoelectric units [2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation on the Thermal Performance of Pulsating Heat Pipe Heat Exchangers

et al. 2020

View full text Add to dashboard Cite

In this study, the vertically-oriented pulsating heat pipe (PHP) heat exchangers charged with either water or HFE-7000 in a filling ratio of 35% or 50% were fabricated to exchange the thermal energy between two air streams in a parallel-flow arrangement. Both the effectiveness of the heat exchangers and the thermal resistance of PHP with a size of 132 × 44 × 200 mm, at a specific evaporator temperature ranging from 55 to 100 °C and a specific airflow velocity ranging from 0.5 to 2.0 m/s were estimated. The results show that the heat pipe charged with HFE-7000 in either filling ratio is likely to function as an interconnected array of thermosiphon under all tested conditions because of the unfavorable tube inner diameter, whereas the water-charged PHP possibly creates the pulsating movement of the liquid and vapor slugs once the evaporator temperature is high enough, especially in a filling ratio of 50%. The degradation in the thermal performance of the HFE-7000-charged PHP heat exchanger resulted from the non-condensable gas in the tube became diminished as the evaporator temperature was increased. By examining the effectiveness of the present heat exchangers, it is suggested that water is a suitable working fluid while employing the PHP heat exchanger at an evaporator temperature higher than 70 °C. On the other hand, HFE-7000 is applicable to the PHP used at an evaporator temperature lower than 70 °C.

show abstract

“…However, obtaining advanced nanostructured materials requires the use of more advanced technologies, such as spark plasma sintering (SPS) and hybrid flash spark plasma sintering. SPS involves direct joule heating of electrically conductive dies (usually graphite), whereas the more advanced hybrid spark SPS employs a thermal runaway to achieve ultrafast sintering with heating rates as high as 10,000 • C/min [11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Preparation and Dielectric Properties of K1/2Na1/2NbO3 Ceramics Obtained from Mechanically Activated Powders

et al. 2020

View full text Add to dashboard Cite

Alkaline based materials have been considered as a replacement for environmentally harmful Pb(Zr,Ti)O3 (PZT) electro-ceramics. In this paper, the K1/2Na1/2NbO3 (KNN) ceramics were prepared in a three stage process: first Nb2O5, Na2CO3, and K2CO3 were milled in a high energy mill (shaker type) for different periods, between 25 h and 100 h, consecutively a solid state reaction was carried out at 550 °C. Finally, the uniaxially pressed samples were sintered at 1000 °C. The reaction temperature is lower for mechanically activated powders than in the case of the conventional solid-state method. The ceramic samples, prepared from the mechanically activated powders, were investigated by dielectric spectroscopy. The influence of the duration of the mechanical activation on the properties of the ceramic materials, e.g., ceramic microstructures, phase transition temperatures, character of the temperature dependences of dielectric permittivity, are discussed.

show abstract

Realizing a stable high thermoelectric zT ∼ 2 over a broad temperature range in Ge_1−x−yGa_xSb_yTe via band engineering and hybrid flash-SPS processing

Abstract: We report a remarkably high and stable thermoelectric zT ∼ 2 by manipulating the electronic bands in hybrid flash-SPSed Ga–Sb codoped GeTe.

Cited by 84 publications

References 75 publications

High‐Performance GeTe‐Based Thermoelectrics: from Materials to Devices

High‐Performance GeTe‐Based Thermoelectrics: from Materials to Devices

Experimental Investigation on the Thermal Performance of Pulsating Heat Pipe Heat Exchangers

Preparation and Dielectric Properties of K1/2Na1/2NbO3 Ceramics Obtained from Mechanically Activated Powders

Contact Info

Product

Resources

About