Enhancement in thermoelectric properties of ZrNiSn-based alloys by Ta doping and Hf substitution

Yang, Xiong; Wang, Yanxia; Min, Ruonan; Chen, Zongning; Guo, Enyu; Kang, Huijun; Li, Linwei; Wang, Tongmin

doi:10.1016/j.actamat.2022.117976

Cited by 23 publications

(27 citation statements)

References 54 publications

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“…In the higher Zr content sample, on the other hand, the thermal and lattice thermal conductivity decreased to 4.6 and 1.9 W/(m·K), respectively (Figure b). Among the MNiSn alloys, the κ l value of 1.9 W/(m·K) at 823 K is lower than that of Ta-doped TiNiSn, Zr and Nb-doped TiNiSn, and Zr-doped TiNiSn as well as Hf-doped ZrNiSn . Although the melt spun and sintered Hf- and Ti-doped ZrNiSn exhibited an ultralow κ l value of 1.0 W/(m·K), close to Debye–Cahill limit in HH alloys, the associated electron scattering at the fine interfaces lowered the power factor.…”

Section: Resultsmentioning

confidence: 82%

Low-Lattice Thermal Conductivity in Zr-Doped Ti₂NiCoSnSb Thermoelectric Double Half-Heusler Alloys

Mishra

Tan

Trivedi

et al. 2023

ACS Appl. Energy Mater.

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The effect of doping on the thermoelectric properties of Half-Heusler (HH) high-entropy alloy (HEA) Ti2NiCoSnSb was studied. Lower thermal conductivity was observed with increased Sb doping. Mass scattering by heavy (Ta, Zr) and light (Al) dopants was studied to further lower the thermal conductivity. Dopants at the level of up to 50% at the Ti site were studied. A high HH phase content was obtained in the Zr-doped samples, and a low-lattice thermal conductivity of 1.9 W/(m·K) was observed. This value is one of the lowest reported lattice thermal conductivities in HH alloys. The poor solubility of Ta led to undissolved Ta in the samples, which enhanced the electrical properties. In the case of Al doping, the NiAl phase raised the power factor value of Ti1.8Al0.2NiCoSn0.5Sb1.5 to 2.2 × 10–3 W/(m·K2), which is almost twice the corresponding value reported for Ti2NiCoSnSb. Interestingly, a maximum ZT of 0.29 was found in all of the doped systems, although the transport mechanism and microstructure varied widely with the type of dopant. An optimum dopant level of 25% of Zr, 7.5% of Ta, and 10% of Al is necessary to obtain the maximum ZT in these alloys. Compared to HH systems, the HH high-entropy alloy (HEA) systems provide a larger composition field for tuning the transport properties by simultaneous doping of multiple elements to lower the thermal conductivity.

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Section: Resultsmentioning

confidence: 82%

Low-Lattice Thermal Conductivity in Zr-Doped Ti₂NiCoSnSb Thermoelectric Double Half-Heusler Alloys

Mishra

Tan

Trivedi

et al. 2023

ACS Appl. Energy Mater.

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“…Due to the existence of natural vacancies produced by Ba evaporation, the undoped sample, which holds rather high hole density, reaches a peak zT of 0.95 at 1012 K. By adding excessive Ba to fill the intrinsic vacancies, the hole density can be optimized to attain a highest zT value of 1.3 in the Ba 1.01 AgSb sample, which is more competitive than other advanced high‐temperature p‐type TE materials. [ 29–31 ] As shown in Figure 1c, the maximum zT value exceeds all the reported results for ZrBeSi‐type (1‐1‐1 type) systems, making BaAgSb one of the most advanced TE materials among Zintl‐phase compounds working at high temperature. [ 32–52 ] The physical origins of the excellent thermoelectric performance will be discussed in the following sections.…”

Section: Resultsmentioning

confidence: 85%

Symmetry‐Guaranteed High Carrier Mobility in Quasi‐2D Thermoelectric Semiconductors

et al. 2023

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Quasi‐2D semiconductors have garnered immense research interest for next‐generation electronics and thermoelectrics due to their unique structural, mechanical, and transport properties. However, most quasi‐2D semiconductors experimentally synthesized so far have relatively low carrier mobility, preventing the achievement of exceptional power output. To break through this obstacle, a route is proposed based on the crystal symmetry arguments to facilitate the charge transport of quasi‐2D semiconductors, in which the horizontal mirror symmetry is found to vanish the electron–phonon coupling strength mediated by phonons with purely out‐of‐plane vibrational vectors. This is demonstrated in ZrBeSi‐type quasi‐2D systems, where the representative sample Ba1.01AgSb shows a high room‐temperature hole mobility of 344 cm2 V−1 S−1, a record value among quasi‐2D polycrystalline thermoelectrics. Accompanied by intrinsically low thermal conductivity, an excellent p‐type zT of ≈1.3 is reached at 1012 K, which is the highest value in ZrBeSi‐type compounds. This work uncovers the relation between electron–phonon coupling and crystal symmetry in quasi‐2D systems, which broadens the horizon to develop high mobility semiconductors for electronic and energy conversion applications.

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“…5b plots the reported maximum zT max for some of the MNiSn (M = Ti, Zr, Hf)-based compounds. 53,57,64,74,79–81 By modulating the Δ S conf , we have obtained a competitive value of zT max for Hf-free Ti 0.57 Zr 0.4 Al 0.02 Ta 0.01 NiSn 0.98 Sb 0.02 . However, Hf substitution at the Ti site can induce a significant increase in mass and strain field fluctuations inside the system, thereby reducing the κ L and improving the thermoelectric performance.…”

Section: Resultsmentioning

confidence: 99%

“…The maximum zT max for some of the MNiSn (M = Ti, Zr, Hf)-based compounds. 53,57,64,74,[79][80][81] Fig. 6 (a) The Vickers microhardness and compressive stress-strain curves for the TiNiSn-based alloys.…”

Section: Mechanical Performancementioning

confidence: 99%

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Ultralow lattice thermal conductivity and improved thermoelectric performance in a Hf-free half-Heusler compound modulated by entropy engineering

et al. 2023

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Enhancement in thermoelectric properties of ZrNiSn-based alloys by Ta doping and Hf substitution

Cited by 23 publications

References 54 publications

Low-Lattice Thermal Conductivity in Zr-Doped Ti₂NiCoSnSb Thermoelectric Double Half-Heusler Alloys

Low-Lattice Thermal Conductivity in Zr-Doped Ti₂NiCoSnSb Thermoelectric Double Half-Heusler Alloys

Symmetry‐Guaranteed High Carrier Mobility in Quasi‐2D Thermoelectric Semiconductors

Ultralow lattice thermal conductivity and improved thermoelectric performance in a Hf-free half-Heusler compound modulated by entropy engineering

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Enhancement in thermoelectric properties of ZrNiSn-based alloys by Ta doping and Hf substitution

Cited by 23 publications

References 54 publications

Low-Lattice Thermal Conductivity in Zr-Doped Ti2NiCoSnSb Thermoelectric Double Half-Heusler Alloys

Low-Lattice Thermal Conductivity in Zr-Doped Ti2NiCoSnSb Thermoelectric Double Half-Heusler Alloys

Symmetry‐Guaranteed High Carrier Mobility in Quasi‐2D Thermoelectric Semiconductors

Ultralow lattice thermal conductivity and improved thermoelectric performance in a Hf-free half-Heusler compound modulated by entropy engineering

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Product

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Low-Lattice Thermal Conductivity in Zr-Doped Ti₂NiCoSnSb Thermoelectric Double Half-Heusler Alloys

Low-Lattice Thermal Conductivity in Zr-Doped Ti₂NiCoSnSb Thermoelectric Double Half-Heusler Alloys