High thermoelectric performance of MgAgSb-based materials
High thermoelectric performance of MgAgSb-based materials
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DOI：
10.1016/j.nanoen.2014.04.012
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发表时间：
2014-07-01
期刊：
影响因子：
17.6
通讯作者：
Ren, Zhifeng
中科院分区：
文献类型：
--
作者：
Zhao, Huaizhou;Sui, Jiehe;Ren, Zhifeng
自20世纪50年代发现以来，碲化铋是唯一一种在20 ~ 150℃温度范围内热电性能系数（ZT）为1 ~ 1.5的热电材料。它主要用于冷却，即使在250摄氏度的热侧和类似20摄氏度的冷侧也尝试了发电。在这里，我们报告了我们在mgagsb基MgAg0.97Sb0.99和MgAg0.96SNi0.005Sb0.99中发现的可比较的ZT值。该材料是由两步工艺的元素球磨粉和热压成致密的块状样品，颗粒小于20纳米。晶粒尺寸小以及结构中的空位和反位等点缺陷是导致室温下导热系数极低的主要原因，其导热系数约为0.7 W m(-1) K-1。室温下ZT值接近1，在475 K时ZT值随温度的升高而增大，达到最高值，接近1.4。我们的发现承诺了一种新的热电材料，具有在20到250摄氏度之间的高热电性能(C) 2014 Elsevier Ltd。版权所有。
Bismuth telluride has been the only thermoelectric material with thermoelectric figure-of-merit (ZT) of 1-1.5 in the temperature range of 20 and 150 degrees C since its discovery in 1950s. It has been primarily used for cooling even though power generation has also been attempted for hot side of 250 degrees C and cold side of similar to 20 degrees C. Here, we report our discovery of comparable ZT values in MgAgSb-based MgAg0.97Sb0.99 and MgAg0.96SNi0.005Sb0.99. The materials are made by ball milling powders of elements in a two-step process and hot pressing the powders into dense bulk samples with grains smaller than 20 nm. The small grain size together with point defects including vacancies and antisites in the structure are the main reasons for the very low thermal conductivity of similar to 0.7 W m(-1) K-1 at room temperature. The ZT values at room temperature are close to 1 and increase with temperature to a maximum of similar to 1.4 at 475 K. Our discovery promises a new class of thermoelectric materials with high thermoelectric performance between 20 and 250 degrees C. (C) 2014 Elsevier Ltd. All rights reserved.