High-temperature thermoelectric properties of La and Fe co-doped Ca-Co-O misfit-layered cobaltites consolidated by spark plasma sintering
High-temperature thermoelectric properties of La and Fe co-doped Ca-Co-O misfit-layered cobaltites consolidated by spark plasma sintering
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DOI：
10.1016/j.jallcom.2013.11.098
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发表时间：
2014-03-05
影响因子：
6.2
通讯作者：
Nan, Ce-Wen
中科院分区：
文献类型：
--
作者：
Butt, Sajid;Liu, Yao-Chun;Nan, Ce-Wen
采用Sol-Gel法制备了Ca3Co4-yFeyO9和Ca3-xLaxCo4-yFeyO9系列陶瓷。X-射线衍射分析表明，在盐岩Ca2CoO_3层中，Fe取代了Co位。Fe在Co位的部分取代同时提高了材料的电导率和热电势，从而提高了材料的功率因数。对于(La，Fe)共掺样品，虽然电导率降低，但热功率得到了充分的提高，从而获得了更高的功率因数。随温度变化的电导率数据表明，对于573K以上的纯样品和掺杂样品，空穴跳跃是主要的导电机制。(La，Fe)共掺杂增加了声子散射，大大抑制了热导率。在1000K时，(La，Fe)共掺杂的ZT值为0.32，比纯Ca3Co4O9的ZT值提高了约70%。(C)2013爱思唯尔B.V.保留所有权利。
A series of Ca3Co4-yFeyO9 and Ca3-xLaxCo4-yFeyO9 ceramics was prepared by sol-gel method followed by spark plasma sintering. The X-ray diffraction analysis indicates that Fe is substituted at the Co-site in rock salt Ca2CoO3 layers. The partial substitution of Fe at Co-site shows a simultaneous increase in the electrical conductivity and thermopower, which results in an increased power factor. For (La, Fe) co-doped specimens, although, the electrical conductivity is decreased but the thermopower is increased sufficiently to obtain a higher power factor. The temperature dependent electrical conductivity data represents that hole-hopping is the dominant conduction mechanism for all the pure and doped specimens above 573 K. The thermal conductivity is greatly suppressed by (La, Fe) co-doping because of the increased phonon scattering. A larger ZT value of 0.32 at 1000 K was achieved with (La, Fe) co-doping which is about 70% higher than that of pure Ca3Co4O9. (C) 2013 Elsevier B.V. All rights reserved.