Is LiI a Potential Dopant Candidate to Enhance the Thermoelectric Performance in Sb-Free GeTe Systems? A Prelusive Study
Is LiI a Potential Dopant Candidate to Enhance the Thermoelectric Performance in Sb-Free GeTe Systems? A Prelusive Study
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DOI：
10.3390/en13030643
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发表时间：
2020-02
期刊：
影响因子：
3.2
通讯作者：
B. Srinivasan;D. Berthebaud;T. Mori
中科院分区：
文献类型：
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作者：
B. Srinivasan;D. Berthebaud;T. Mori
作为有毒 PbTe 基热电材料的可行替代品，GeTe 基材料正在成为可靠的替代品。为了评估 LiI 作为热电 GeTe 掺杂剂的适用性，这篇简短的通讯中介绍了通过火花等离子烧结 (SPS) 加工的 GeTe 1−x LiI x ( x = 0–0.02) 合金的热电性能的初步研究。 2 mol% LiI 掺杂的 GeTe 组合物在 773 K 时获得了最大热电品质因数 zT ~ 1.2，这得益于热导率显着降低和功率因数略有改善的综合优势。由于Li诱导的“赝空位”和纳米沉淀物的形成，载热声子的散射导致了晶格热导率的显着抑制，因此与之前报道的原始GeTe和富Sb (GeTe) x (LiSbTe 2 ) 2 化合物相比，无Sb (GeTe) 0.98 (LiI) 0.02 样品的 zT 有所提高。
As a workable substitute for toxic PbTe-based thermoelectrics, GeTe-based materials are emanating as reliable alternatives. To assess the suitability of LiI as a dopant in thermoelectric GeTe, a prelusive study of thermoelectric properties of GeTe 1−x LiI x ( x = 0–0.02) alloys processed by Spark Plasma Sintering (SPS) are presented in this short communication. A maximum thermoelectric figure of merit, zT ~ 1.2, was attained at 773 K for 2 mol% LiI-doped GeTe composition, thanks to the combined benefits of a noted reduction in the thermal conductivity and a marginally improved power factor. The scattering of heat carrying phonons due to the presumable formation of Li-induced “pseudo-vacancies” and nano-precipitates contributed to the conspicuous suppression of lattice thermal conductivity, and consequently boosted the zT of the Sb-free (GeTe) 0.98 (LiI) 0.02 sample when compared to that of pristine GeTe and Sb-rich (GeTe) x (LiSbTe 2 ) 2 compounds that were reported earlier.