Kirievsky K, Shlimovich M, Fuks D, Gelbstein Y
Materials Engineering Department, Ben Gurion University of the Negev, Beer Sheva, Israel.
Phys Chem Chem Phys. 2014 Oct 7;16(37):20023-9. doi: 10.1039/c4cp02868f.
Novel approaches for the development of highly efficient thermoelectric materials capable of a direct conversion of heat into electricity, are being constantly investigated. TiNiSn based half-Heusler alloys exhibit a high thermoelectric potential for practical, renewable power generation applications. The main challenge of further enhancement of the thermoelectric efficiency of these alloys lies in the reduction of the associated high lattice thermal conductivity values without adversely affecting the electronic transport properties. The current manuscript theoretically investigates two possible routes for overcoming this limitation in TiNiSn alloys. On the one hand, the influence of nano-grained structure of TiNiSn on the electronic structure of the material is theoretically demonstrated. On the other hand, the potential for thermal conductivity reduction upon increasing the Ni fraction in the intermetallic TiNiSn compound via the formation of metallic TiNi2Sn nanoparticles is also shown. Using the applied approach, a useful route for optimizing both the electronic and thermal properties of half-Heusler TiNiSn, for practical thermoelectric applications, is demonstrated.
能够将热直接转化为电的高效热电材料开发的新方法正在不断研究中。基于TiNiSn的半赫斯勒合金在实际可再生发电应用中展现出很高的热电潜力。进一步提高这些合金热电效率的主要挑战在于降低相关的高晶格热导率值，同时又不负面影响电子输运性能。当前的论文从理论上研究了克服TiNiSn合金这一限制的两种可能途径。一方面，从理论上证明了TiNiSn纳米晶粒结构对材料电子结构的影响。另一方面，还表明了通过形成金属TiNi2Sn纳米颗粒来增加金属间化合物TiNiSn中Ni含量时降低热导率的潜力。通过应用该方法，展示了一条优化半赫斯勒TiNiSn的电子和热性能以用于实际热电应用的有效途径。
