Grain Boundary Engineering for Achieving High Thermoelectric Performance in n-Type Skutterudites
Grain Boundary Engineering for Achieving High Thermoelectric Performance in n-Type Skutterudites
复制标题
用于实现 n 型方钴矿高热电性能的晶界工程
DOI：
10.1002/aenm.201602582
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发表时间：
2017-07-05
影响因子：
27.8
通讯作者：
Sui, Jiehe
中科院分区：
文献类型：
--
作者：
Meng, Xianfu;Liu, Zihang;Sui, Jiehe
晶界或相边界在体热电材料中的载流子和声子输运中起着关键作用。以往关于晶界控制的研究主要集中在减小晶粒尺寸或形成纳米夹杂物上。本文首次采用液相压制法制备了Sb含量过量的Yb填充CoSb 3，其具有典型的低角度晶界和密集的位错阵列特征。Seebeck系数通过位错阵列的能量过滤效应显示出显著的增加，而载流子迁移率几乎没有恶化，这在很宽的温度范围内显着提高了功率因数，室温值约为47 μ W cm（-2）K-1。同时，晶格热导率可以进一步抑制通过散射声子通过密集位错散射。其结果是，最高的平均优值ZT的近似1.08，从300至850 K，可以实现的最好的报告结果相比，单或三填充Skutterudites。这项工作清楚地指出，小角度晶界液相压实法制造可以同时优化电和热输运性能，导致功率因数和ZT的显着提高。
Grain or phase boundaries play a critical role in the carrier and phonon transport in bulk thermoelectric materials. Previous investigations about controlling boundaries primarily focused on the reducing grain size or forming nanoinclusions. Herein, liquid phase compaction method is first used to fabricate the Yb-filled CoSb3 with excess Sb content, which shows the typical feature of low-angle grain boundaries with dense dislocation arrays. Seebeck coefficients show a dramatic increase via energy filtering effect through dislocation arrays with little deterioration on the carrier mobility, which significantly enhances the power factor over a broad temperature range with a high room-temperature value around 47 mu W cm(-2) K-1. Simultaneously, the lattice thermal conductivity could be further suppressed via scattering phonons via dense dislocation scattering. As a result, the highest average figure of merit ZT of approximate to 1.08 from 300 to 850 K could be realized, comparable to the best reported result of single or triple-filled Skutterudites. This work clearly points out that low-angle grain boundaries fabricated by liquid phase compaction method could concurrently optimize the electrical and thermal transport properties leading to an obvious enhancement of both power factor and ZT.