Rabøl Jørgensen Lasse, Moeslund Zeuthen Christian, Andersen Borup Kasper, Roelsgaard Martin, Lau Nyborg Broge Nils, Beyer Jonas, Brummerstedt Iversen Bo
Department of Chemistry, University of Aarhus, Langelandsgade 140, Aarhus C 8000, Denmark.
IUCrJ. 2020 Jan 1;7(Pt 1):100-104. doi: 10.1107/S205225251901580X.
The application of thermoelectrics for energy harvesting depends strongly on operational reliability and it is therefore desirable to investigate the structural integrity of materials under operating conditions. We have developed an setup capable of simultaneously measuring X-ray scattering data and electrical resistance on pellets subjected to electrical current. Here, investigations of β-ZnSb are reported at current densities of 0.5, 1.14 and 2.3 A mm. At 0.5 A mm no sample decomposition is observed, but Rietveld refinements reveal increased zinc occupancy from the anode to the cathode demonstrating zinc migration under applied current. At 1.14 A mm β-ZnSb decomposes into ZnSb, but pair distribution function analysis shows that ZnSb units are preserved during the decomposition. This identifies the mobile zinc in β-ZnSb as the linkers between the ZnSb units. At 2.3 A mm severe Joule heating triggers transition into the γ-ZnSb phase, which eventually decomposes into ZnSb, demonstrating Zn ion mobility also in γ-ZnSb under electrical current.
热电材料在能量收集方面的应用很大程度上取决于运行可靠性，因此研究材料在工作条件下的结构完整性是很有必要的。我们开发了一种装置，能够同时测量在通有电流的颗粒上的X射线散射数据和电阻。在此，报告了在电流密度为0.5、1.14和2.3 A/mm² 时对β-ZnSb的研究。在0.5 A/mm² 时，未观察到样品分解，但Rietveld精修显示从阳极到阴极锌占有率增加，表明在施加电流的情况下锌发生了迁移。在1.14 A/mm² 时，β-ZnSb分解为ZnSb，但对分布函数分析表明，在分解过程中ZnSb单元得以保留。这表明β-ZnSb中的可移动锌是ZnSb单元之间的连接体。在2.3 A/mm² 时，严重的焦耳热引发向γ-ZnSb相的转变，最终分解为ZnSb，这表明在电流作用下γ-ZnSb中也存在锌离子迁移。
