Enhancing thermoelectric properties in TiNiSi structure-type semimetal ZrNiSi by doping

Kumar, Shiva; Kumar, Ankit; Ghosh, Prasenjit; Singh, Surjeet

doi:10.1103/physrevmaterials.6.065401

Cited by 4 publications

(5 citation statements)

References 38 publications

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“…The performance of our TiNiSi sample is comparable to the literature ( zT =6×10 −3 at 800 K), with V substitution leading to a performance increase to zT =0.035 at 600 K, largely driven by an increase in S(T) [8] . Work on ZrNiSi demonstrated a similar peak zT =0.02 at 700 K in samples doped n‐type with Sb (and zT =5×10 −3 at 900 K for ZrNiSi) [9a] . In the literature studies on TiNiSi and ZrNiSi, n‐type doping improved S(T) but overall S 2 /ρ remains modest, not exceeding 0.5 mW m −1 K −2 , and peak S(T) values near −40 μV K −1 [8–9] .…”

Section: Discussionsupporting

confidence: 80%

“…From the perspective of semiconductor thermoelectrics, this trend is unexpected, as increasing doping levels usually leads to a decrease in S . A ZrNiSi sample with simultaneous Sb doping and Hf alloying on the Ti site, reached zT =0.06 at 950 K. The combined impact of Sb doping and Hf alloying reduced κ lat from 11 W m −1 K −1 to 3 W m −1 K −1 , demonstrating that low κ are possible in this structure type [9a] . The literature TiNiSi and ZrNiSi samples do not show the increase in S(T) on cooling that our sample shows, and measurement of zT below 300 K would be of interest.…”

Section: Discussionmentioning

confidence: 95%

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Thermoelectric properties and Kondo transition in the pseudo‐gap metals TiNiSi and TiNiGe

Downie

Kennedy

Biswas

et al. 2023

Zeitschrift anorg allge chemie

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Materials with the TiNiSi structure have recently been highlighted as potential thermoelectric materials. Here we report the thermoelectric properties of TiNiX (X=Si and Ge). Both materials behave as defective metals or heavily doped degenerate semiconductors. Room temperature Seebeck coefficients are −45 μV K−1 (Si) and −20 μV K−1 (Ge) with electrical resistivities of 0.5–1 mΩ cm. The lattice thermal conductivities are 8 W m−1 K−1 (Si) and 6 W m−1 K−1 (Ge) at 360 K, which is promising in the absence of alloying. The calculated power factors and figures of merit remain small, with the largest S2/ρ=0.17 mW m−1 K−2 and peak zT=5×10−3 seen in TiNiSi near 300 K. Both compositions show Kondo behaviour at low‐temperatures, linked to the emergence of local moment magnetism, and have substantial magnetoresistance effects at 2 K. This work provides property characterisation for two members of this large class of intermetallic materials.

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Section: Discussionsupporting

confidence: 80%

Section: Discussionmentioning

confidence: 95%

Thermoelectric properties and Kondo transition in the pseudo‐gap metals TiNiSi and TiNiGe

Downie

Kennedy

Biswas

et al. 2023

Zeitschrift anorg allge chemie

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“…For the suppression of bipolar thermal conductivity ( κ bip ), strategies of increasing the bandgap and the majority carrier concentration are primarily used. [ 29 ] As shown in Figure 3e, the lattice thermal conductivity decreases from 323 to 973 K. A small anisotropic v g is observed due to the anisotropic lattice parameter. A decrease in v g would significantly decrease the thermal conductivity.…”

Section: Resultsmentioning

confidence: 93%

Thermoelectric Transport of a Novel Zr‐Based Half‐Heusler High‐Entropy Alloy

Adamo,

Srivastava,

Legese

et al. 2023

Energy Tech

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The high‐entropy concept, extensively studied in alloys and ceramics, has produced intriguing results, but its use in thermoelectric materials is still in its infancy. This study introduces a pioneering high‐entropy half‐Heusler (hH) alloy, ZrTiNiFeSnSb, synthesized via arc melting and heat treatment. Phonon scattering from multiple elements significantly reduces the lattice thermal conductivity of the alloy, which decreases to a minimum of 3.5 Wm−1 K−1 (700 K) in this material. The experimental thermal data matches the density functional theory calculations for phonon dispersion, phonon group velocity, and Grüneisen parameters. This demonstrates that crystal distortion induced anharmonicity slows the alloy's phonon heat transport, which is suitable for thermoelectric applications. Notably possessing elevated electrical conductivity and a moderate Seebeck coefficient, this high‐entropy hH alloy emerges as a promising thermoelectric material for energy harvesting.

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“…Since the electron concentration in n0.1Si and p0.001Si in Table S2 is lower than ZrNiSn, and all the work function (W s ) values of Si are larger than those of ZrNiSn 6 in Table S3, it precludes the possibility of electron flow from Si to ZrNiSn during band alignment. From the XRD patterns in Figure S1 and EDS results in Figure 2a, semimetal ZrNiSi with high electrical conductivity may exist, 38 contributing to the increased carriers. Furthermore, the formation of ZrNiSi may cause Zr vacancy and thus induce in-gap states.…”

Section: Resultsmentioning

confidence: 99%

Thermoelectric Performance Improvement in the ZrNiSn-Based Composite via Modulating Si Addition

Jia,

Zhu,

Shi

et al. 2024

ACS Appl. Mater. Interfaces

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To ensure optimal performance, ZrNiSn is required to possess a low thermal conductivity and exhibit minimal bipolar effects under high-temperature conditions. This study demonstrates the integration of silicon (Si) at different doping levels into ZrNiSn. The composites consist of secondary phases of in situ ZrNiSi and Si. At a temperature of 873 K, the Seebeck coefficient experiences a 16% increase, despite the charge carrier concentration increasing three times as a result of the electron injection from ZrNiSi. The phenomenon can be elucidated by the introduction of Si, which causes energy filtering and inhibits the flow of minority charge carriers. When the doping levels in n-or ptype Si reach high levels (10 19 to 10 20 cm −3 ), the mixed interfaces ZrNiSn/ZrNiSi and ZrNiSn/Si reduce the thermal conductivity by 15%, resulting in a 50% increase in zT. These findings indicate that electron transfer in ZrNiSn can be regulated by precise doping in Si. They also demonstrate that incorporating an optimal p-type semiconductor can enhance the thermoelectric performance of ntype ZrNiSn. Additionally, a novel approach is proposed to separate electrical conductivity and the Seebeck coefficient by designing unique secondary phase interfaces.

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Enhancing thermoelectric properties in TiNiSi structure-type semimetal ZrNiSi by doping

Cited by 4 publications

References 38 publications

Thermoelectric properties and Kondo transition in the pseudo‐gap metals TiNiSi and TiNiGe

Thermoelectric properties and Kondo transition in the pseudo‐gap metals TiNiSi and TiNiGe

Thermoelectric Transport of a Novel Zr‐Based Half‐Heusler High‐Entropy Alloy

Thermoelectric Performance Improvement in the ZrNiSn-Based Composite via Modulating Si Addition

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