Thermoelectric Properties of In&lt;i&gt;&lt;sub&gt;x&lt;/sub&gt;&lt;/i&gt;FeCo&lt;sub&gt;3&lt;/sub&gt;Sb&lt;sub&gt;12&lt;/sub&gt; Consisting Mainly of In-Filled &lt;i&gt;p&lt;/i&gt;-Type Skutterudites

Kim, Jungmin; Kurosaki, Ken; Choi, Seongho; Ohishi, Yuji; Muta, Hiroaki; Yamanaka, Shinşuke; Takahashi, Motomitsu; Tanaka, Junya

doi:10.2320/matertrans.m2017089

Cited by 4 publications

(1 citation statement)

References 29 publications

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“…In order to make it practical in real applications, it is essential to lower the zT max temperature for enhancement of zT ave . Single-and double-filling strategies have been utilized for improving zT of p-type skutterudites (p-SKD) [22][23][24][25][26][27][28][29][30]. The resonant frequencies of the fillers vary between 42 cm −1 and 142 cm −1 from rare-earth elements to alkali metals [31] so that phonons in different frequency ranges can be effectively scattered via phonon resonant scattering by the multi-fillers, which have been widely used for n-SKD [16,17,32].…”

Section: Introductionmentioning

confidence: 99%

High-Efficiency Skutterudite Modules at a Low Temperature Gradient

Stokes

Poudel

et al. 2019

Energies

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Thermoelectric skutterudite materials have been widely investigated for their potential application in mid-temperature waste heat recovery that has not been efficiently utilized A large amount of research has focused on developing materials with a high thermoelectric figure of merit (zT). However, the translation of material properties to device performance has limited success. Here, we demonstrate single-filling n-type Yb0.25Fe0.25Co3.75Sb12 and multi-filling La0.7Ti0.1Ga0.1Fe2.7Co1.3Sb12 skutterudites with a maximum zT of ~1.3 at 740 K and ~0.97 at 760 K. The peak zT of skutterudites usually occurs above 800 K, but, as shown here, the shift in peak zT to lower temperatures is beneficial for enhancing conversion efficiency at a lower hot-side temperature. In this work, we have demonstrated that the Fe-substitution significantly reduces the thermal conductivity of n-type skutterudite, closer to p-type skutterudite thermal conductivity, resulting in a module that is more compatible to operate at elevated temperatures. A uni-couple skutterudite module was fabricated using a molybdenum electrode and Ga–Sn liquid metal as the thermal interface material. A conversion efficiency of 7.27% at a low temperature gradient of 366 K was achieved, which is among the highest efficiencies reported in the literature at this temperature gradient. These results highlight that peak zT shift and optimized module design can improve conversion efficiency of thermoelectric modules at a low temperature gradient.

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Section: Introductionmentioning

confidence: 99%

High-Efficiency Skutterudite Modules at a Low Temperature Gradient

Stokes

Poudel

et al. 2019

Energies

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Enhancement of thermoelectric properties of p-type single-filled skutterudites CexFeyCo4-ySb12 by tuning the Ce and Fe content

et al. 2018

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CoSb3-based filled skutterudites are known as good n-type thermoelectric (TE) materials. However, the p-type ones have not been intensively investigated. In this study, we focus on Ce-filled Fe-substituted CoSb3 as p-type skutterudites, where Fe will act as a hole dopant. Polycrystalline samples with nominal compositions of CexFeyCo4-ySb12 (x = 0.8, 0.9, 1.0 and y = 3.0, 3.5) are synthesized and the high temperature TE properties are investigated. All the samples show the p-type conduction as we expected. It is found that the samples with y = 3.5 exhibit clearly lower κlat values than those of the samples with y = 3.0, meaning that the Fe/Co substitution is more predominant than the Ce filling for the κlat reduction. The maximum zT value observed in this study is 0.78 at 704 K for the sample with x = 1.0, y = 3.5, which is close to the best value reported so far for Ce-filled Fe-substituted CoSb3-based p-type skutterudites.

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