n-Type skutterudites (R,Ba,Yb)yCo4Sb12 (R = Sr, La, Mm, DD, SrMm, SrDD) approaching ZT ≈ 2.0
n-Type skutterudites (R,Ba,Yb)yCo4Sb12 (R = Sr, La, Mm, DD, SrMm, SrDD) approaching ZT ≈ 2.0
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DOI：
10.1016/j.actamat.2013.09.039
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发表时间：
2014-01-15
期刊：
影响因子：
9.4
通讯作者：
Eibl, O.
中科院分区：
文献类型：
--
作者：
Rogl, G.;Grytsiv, A.;Eibl, O.
研究了不同填料R （R = Sr, La, Mm， DD, SrMm, SrDD，其中Mm代表混合稀土，DD代表钕）对标称成分为（R0.33Ba0.33Yb0.33）（0.35）Co4Sb12.3的三填充和多填充n型滑石物理性能的影响。与作者以前的工作和文献的值进行比较表明，即使填料的填充分数和总填充水平的微小变化也会影响功率因数和导热系数。由不同化学性质的多种填料局部填充后，可获得高功率因数（823 K时为>6 mW m(-1) K-2），同时导热系数低，823 K时ZT = 1.4。相反，在（Sr0.25Ba0.25Yb0.50）（0.5）Co4Sb12.5中作为次级相的Yb2O3由于功率因数降低和晶格导热系数增加而显著降低了热电（TE）性能。然而，这些杂质的均匀纳米级分布大大提高了TE性能，导致835 K时的ZT值接近1.6。经高压扭转剧烈塑性变形后，其ZT值可进一步提高到1.9 （835 K）。(C) 2013材料学报Elsevier Ltd.出版。版权所有。
The influence of various fillers R (R = Sr, La, Mm, DD, SrMm, SrDD with Mm standing for mischmetal and DD for didymium) on the physical properties of the triple- and multifilled n-type skutterudites with the nominal composition (R0.33Ba0.33Yb0.33)(0.35)Co4Sb12.3 is investigated. In comparison to values from previous works of the authors and from the literature it is demonstrated that even small changes in the filling fractions of the fillers as well as in the total filling level influence the power factor and the thermal conductivity. These skutterudites, partially filled with multiple fillers of different chemical nature, can achieve high power factors (>6 mW m(-1) K-2 at 823 K) and at the same time low thermal conductivity, resulting in ZT = 1.4 at 823 K. On the contrary, Yb2O3 as a secondary phase in (Sr0.25Ba0.25Yb0.50)(0.5)Co4Sb12.5 significantly reduces the thermoelectric (TE) performance due to a decreased power factor and an increased lattice thermal conductivity. However, a homogeneous nanoscale distribution of these impurities substantially improves the TE performance, resulting in ZT values of similar to 1.6 at 835 K. The ZT value of this skutterudite could be further enhanced to 1.9 (at 835 K) after severe plastic deformation via high-pressure torsion. (C) 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.