Impact of Ni content on the thermoelectric properties of half-Heusler TiNiSn

Tang, Yaqiong; Li, Xiaoshuang; Martin, Lukas H.J.; Reyes, Eduardo Cuervo; Ivas, Toni; Leinenbach, Christian; Anand, Shashwat; Peters, Matthew; Snyder, G. Jeffrey; Battaglia, Corsin

doi:10.1039/c7ee03062b

Cited by 104 publications

(97 citation statements)

References 34 publications

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“…The magnitude of ρ follows the Ni 4d site occupancy and reduces from 9 mΩ cm (Ni 4d = 0.019) to 2 mΩ cm (Ni 4d = 0.08). S 2 /ρ increases from 0.5–1 mW m −1 K −2 at 313 K to maximum values of 2.5–3 mW m −1 K −2 at 550–700 K. These values are comparable to other literature reports [ 16 , 19 , 25 ], although in some studies larger S 2 /ρ ≥ 4 mW m −1 K −2 have been reported [ 18 , 35 ]. The y = 0.25 sample contains 26 wt % metallic FH phase and this sample should be considered a composite of HH (Ni 4d = 0.09) and FH phases.…”

Section: Resultssupporting

confidence: 88%

Impact of Interstitial Ni on the Thermoelectric Properties of the Half-Heusler TiNiSn

et al. 2018

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TiNiSn is an intensively studied half-Heusler alloy that shows great potential for waste heat recovery. Here, we report on the structures and thermoelectric properties of a series of metal-rich TiNi1+ySn compositions prepared via solid-state reactions and hot pressing. A general relation between the amount of interstitial Ni and lattice parameter is determined from neutron powder diffraction. High-resolution synchrotron X-ray powder diffraction reveals the occurrence of strain broadening upon hot pressing, which is attributed to the metastable arrangement of interstitial Ni. Hall measurements confirm that interstitial Ni causes weak n-type doping and a reduction in carrier mobility, which limits the power factor to 2.5–3 mW m−1 K−2 for these samples. The thermal conductivity was modelled within the Callaway approximation and is quantitively linked to the amount of interstitial Ni, resulting in a predicted value of 12.7 W m−1 K−1 at 323 K for stoichiometric TiNiSn. Interstitial Ni leads to a reduction of the thermal band gap and moves the peak ZT = 0.4 to lower temperatures, thus offering the possibility to engineer a broad ZT plateau. This work adds further insight into the impact of small amounts of interstitial Ni on the thermal and electrical transport of TiNiSn.

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Section: Resultssupporting

confidence: 88%

Impact of Interstitial Ni on the Thermoelectric Properties of the Half-Heusler TiNiSn

et al. 2018

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“…60 For our samples, the alloy scattering most likely originates from the X-site, as there is no evidence for the presence of substantial amounts of interstitial Ni from the NPD analysis (Table S1 †). Recent literature has conrmed the suppression of the electron mobility by interstitial Ni, 46,62,63 and our results on interstitial Cu are therefore highly relevant as they afford the possibility of increased phonon scattering without detriment to the electrical transport. This very different impact is supported by our DFT calculations that show the presence of in-gap states for interstitial Ni, which provide a possible route for carrier scattering, while these are absent in the Cu case.…”

Section: Single Parabolic Band Modellingmentioning

confidence: 59%

Suppression of thermal conductivity without impeding electron mobility in n-type XNiSn half-Heusler thermoelectrics

et al. 2019

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“…However, it is difficult to determine the excess amount of interstitial B atoms since there is a controversial solid solubility limit of B in the vacant position [20][21][22][23][24]. Recently, a convincing study on the solid solubility of Ni in the vacant position of TiNi 1+x Sn half-Heusler has been conducted by using the phase diagram technique [25]. The narrow temperature-dependent solubility range (e.g., 0 ≤ x ≤ 0:06 at 1223 K in TiNi 1+x Sn) was observed through phase boundary mapping on a Ti-Ni-Sn phase diagram.…”

Section: Introductionmentioning

confidence: 99%

Phase Boundary Mapping in ZrNiSn Half-Heusler for Enhanced Thermoelectric Performance

Yang

Wang

et al. 2020

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The solubility range of interstitial Ni in the ZrNi1+xSn half-Heusler phase is a controversial issue, but it has an impact on the thermoelectric properties. In this study, two isothermal section phase diagrams of the Zr-Ni-Sn ternary system at 973 K and 1173 K were experimentally constructed based on the binary phase diagrams of Zr-Ni, Zr-Sn, and Ni-Sn. The thermodynamic equilibrium phases were obtained after a long time of heating treatment on the raw alloys prepared by levitation melting. Solubilities of x<0.07 at 973 K and x<0.13 at 1173 K were clearly indicated. An intermediate-Heusler phase with a partly filled Ni void was observed, which is believed to be beneficial to the lowered lattice thermal conductivity. The highest ZT value~0.71 at 973 K was obtained for ZrNi1.11Sn1.04. The phase boundary mapping provides an important instruction for the further optimization of ZrNiSn-based materials and other systems.

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Impact of Ni content on the thermoelectric properties of half-Heusler TiNiSn

Abstract: Thermoelectric properties vary dramatically between two boundary compositions of Ni-rich and Ni-poor TiNiSn, up to 25% in zT.

Cited by 104 publications

References 34 publications

Impact of Interstitial Ni on the Thermoelectric Properties of the Half-Heusler TiNiSn

Impact of Interstitial Ni on the Thermoelectric Properties of the Half-Heusler TiNiSn

Suppression of thermal conductivity without impeding electron mobility in n-type XNiSn half-Heusler thermoelectrics

Phase Boundary Mapping in ZrNiSn Half-Heusler for Enhanced Thermoelectric Performance

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