Nanostructured Materials Research Laboratory, Department of Materials Science and Engineering, University of Utah, Salt Lake City, Utah, 84112, USA.
Sci Rep. 2017 Mar 20;7:44621. doi: 10.1038/srep44621.
The potential of thermoelectric materials to generate electricity from the waste heat can play a key role in achieving a global sustainable energy future. In order to proceed in this direction, it is essential to have thermoelectric materials that are environmentally friendly and exhibit high figure of merit, ZT. Oxide thermoelectric materials are considered ideal for such applications. High thermoelectric performance has been reported in single crystals of CaCoO. However, for large scale applications single crystals are not suitable and it is essential to develop high-performance polycrystalline thermoelectric materials. In polycrystalline form, CaCoO is known to exhibit much weaker thermoelectric response than in single crystal form. Here, we report the observation of enhanced thermoelectric response in polycrystalline CaCoO on doping Tb ions in the material. Polycrystalline CaTbCoO (x = 0.0-0.7) samples were prepared by a solid-state reaction technique. Samples were thoroughly characterized using several state of the art techniques including XRD, TEM, SEM and XPS. Temperature dependent Seebeck coefficient, electrical resistivity and thermal conductivity measurements were performed. A record ZT of 0.74 at 800 K was observed for Tb doped CaCoO which is the highest value observed till date in any polycrystalline sample of this system.
热电材料从废热中发电的潜力在实现全球可持续能源未来方面可以发挥关键作用。为了朝着这个方向前进，必须要有环保且具有高品质因数 ZT 的热电材料。氧化物热电材料被认为非常适合这种应用。在 CaCoO 单晶中已经报道了很高的热电性能。然而，对于大规模应用来说，单晶并不适用，开发高性能多晶热电材料至关重要。在多晶形式下，CaCoO 的热电响应比单晶形式弱得多。在这里，我们报告了在掺杂 Tb 离子的材料中观察到多晶 CaCoO 增强的热电响应。通过固态反应技术制备了多晶 CaTbCoO（x=0.0-0.7）样品。使用包括 XRD、TEM、SEM 和 XPS 在内的多种最先进技术对样品进行了彻底的表征。进行了温度相关的塞贝克系数、电阻率和热导率测量。对于 Tb 掺杂的 CaCoO，观察到了 0.74 的创纪录 ZT 值，这是在该系统的任何多晶样品中迄今为止观察到的最高值。
