Rodrigues João Elias F S, Gainza Javier, Serrano-Sánchez Federico, Ferrer Mateus M, Fabris Guilherme S L, Sambrano Julio R, Nemes Norbert M, Martínez José L, Popescu Catalin, Alonso José A
Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, E-28049 Madrid, Spain.
European Synchrotron Radiation Facility, ESRF, 71 Avenue des Martyrs, 38000 Grenoble, France.
Inorg Chem. 2021 May 17;60(10):7413-7421. doi: 10.1021/acs.inorgchem.1c00682. Epub 2021 Apr 26.
Skutterudite-type compounds based on □CoSb pnictide are promising for thermoelectric application due to their good Seebeck values and high carrier mobility. Filling the 8 voids (in the cubic space group 3̅) with different elements (alkali, alkali earth, and rare earth) helps to reduce the thermal conductivity and thus increases the thermoelectric performance. A systematic characterization by synchrotron X-ray powder diffraction of different M-filled CoSb (M = K, Sr, La, Ce, and Yb) skutterudites was carried out under high pressure in the range ∼0-12 GPa. The isothermal equations of state (EOS) were obtained in this pressure range and the Bulk moduli () were calculated for all the filled skutterudites, yielding unexpected results. A lattice expansion due to the filler elements fails in the description of the Bulk moduli. Topochemical studies of the filler site environment exhibited a slight disturbance and an increased ionic character when the filler is incorporated. The mechanical properties by means of Bulk moduli resulted in being sensitive to the presence of filler atoms inside the skutterudite voids, being affected by the covalent/ionic exchange of the Co-Sb and Sb-Sb bonds.
基于□CoSb 磷化物的方钴矿型化合物因其良好的塞贝克值和高载流子迁移率而在热电应用方面具有潜力。用不同元素（碱金属、碱土金属和稀土）填充8个空隙（在立方空间群3̅中）有助于降低热导率，从而提高热电性能。在约0 - 12 GPa的高压下，利用同步辐射X射线粉末衍射对不同M填充的CoSb（M = K、Sr、La、Ce和Yb）方钴矿进行了系统表征。在该压力范围内获得了等温状态方程（EOS），并计算了所有填充方钴矿的体模量（），得出了意想不到的结果。由填充元素引起的晶格膨胀未能描述体模量。填充位点环境的拓扑化学研究表明，当掺入填充剂时，会有轻微干扰且离子特性增加。通过体模量得到的力学性能结果表明，其对方钴矿空隙内填充原子的存在很敏感，受到Co - Sb和Sb - Sb键的共价/离子交换的影响。
