铟填充Skutterudite化合物的晶体结构和热电性能

Crystal Structures and Thermoelectric Properties of In-filled Skutterudites

用熔融法结合放电等离子快速烧结技术(SPS)制备出单相的铟填充p型Skutterudite化合物InyFexCo4-xSb12。Rietveld精确化结果表明:所制备的InyFexCo4-xSb12化合物具有Skutterudite结构;与CoSb3相比,InyFexCo4-xSb12化合物的Sb-Sb键长增加,说明In原子填充进入了Skutterudite结构中的Sb二十面体空洞;In的原子位移参数比框架原子Sb、Fe/Co的大,说明In在空洞中具有扰动效应。热电性能测试结果表明:随着In原子填充量的增加,InyFexCo4-xSb12化合物的电导率减小、Seebeck系数增加、热导率降低,In0.29Fe1.30Co2.70Sb12化合物在725K时具有最大的热电性能指数ZTmax值(0.71)。

The single phase In-filled Skutterudites InyFexCo4-xSb12 had been prepared by melting method combining with spark plasma sintering technique （SPS）.The results of Rietveid refinement show that InyFexCo4-xSb12 samples possess Skutterudite structures, and Sb-Sb bond length of InyFexCo4-xSb12 increases as compared with that of unfilled CoSb3, which demonstrates that In atom has filled into the Sb icosahedron cages in Skutterudite structure. The atomic displacement parameter of In is larger than those of framework atoms Sb, Fe and Co, indicating that the filling atom In has rattling effect on the Sb icosahedron cages. The effects of filling atom In on the thermoelectric properties of InyFexCo4-xSb12 were investigated. With the In filling fraction increasing, the electrical conductivity decreases, the Seebeck coefficient increases and the thermal conductivity decreases. A maximum dimensionless figure of merit ZT reaches 0.71 at 725 K for InyFexCo4-xSb12 compound.