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DOI	10.1039/c7ee03062b
	Impact of Ni content on the thermoelectric properties of half-Heusler TiNiSn
	Tang Y.; Li X.; Martin L.H.J.; Cuervo Reyes E.; Ivas T.; Leinenbach C.; Anand S.; Peters M.; Snyder G.J.; Battaglia C.
发表日期	2018
ISSN	17545692
起始页码	311
结束页码	320
卷号	11 期号:2
英文摘要	From phase boundary mapping, we find that the thermoelectric TiNiSn half-Heusler phase shows a narrow solubility range on the Ti-Ni-Sn phase diagram primarily in the range of excess Ni that can be approximated as TiNi1+xSn, where x is temperature dependent with 0 ≤ x ≤ 0.06 at 1223 K. Four phase boundary compositions with different Ni contents associated with four three-phase regions are identified. We characterize the thermoelectric properties of these stable compositions and find significant difference between Ni-rich and Ni-poor phase boundary compositions of TiNiSn, which amounts up to 41%, 58%, and 25% difference in the Seebeck coefficient, lattice thermal conductivity, and thermoelectric figure of merit respectively. This explains the large discrepancy of literature data on the thermoelectric properties of TiNiSn within a unified phase diagram framework. We demonstrate that Ni-rich TiNiSn results in a narrower band gap using the Goldsmid formula, which we interpret to be due to the formation of an impurity band from interstitial Ni in the forbidden gap as previously suggested. Interstitial Ni atoms scatter both electrons and phonons, with the latter effect being much stronger, thus a lower lattice thermal conductivity compensates for the decrease in electron mobility leading to a high zT value of 0.6 at 850 K for intrinsic Ni-rich TiNiSn. With Sb doping, the carrier concentration in these stable boundary compositions can be tuned but the distinct features in their transport properties remain unchanged. A maximum zT value of 0.6 was also achieved at 850 K for intrinsic Ni-poor TiNiSn upon Sb doping. © 2018 The Royal Society of Chemistry.
英文关键词	Carrier concentration; Crystal lattices; Energy gap; Nickel; Phase boundaries; Phase diagrams; Ternary alloys; Thermal conductivity; Thermoelectric equipment; Thermoelectricity; Tin alloys; Electrons and phonons; Lattice thermal conductivity; Phase boundary composition; Solubility range; Temperature dependent; Thermoelectric figure of merit; Thermoelectric properties; Three-phase regions; Titanium alloys; electrical property; electron; nickel; temperature effect; thermal conductivity
语种	英语
来源期刊	Energy & Environmental Science
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/190326
作者单位	Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, 8600, Switzerland; Department of Earth Sciences, Institute for Geochemistry and Petrology, ETH Zurich, Zürich, 8092, Switzerland; Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, United States
推荐引用方式 GB/T 7714	Tang Y.,Li X.,Martin L.H.J.,et al. Impact of Ni content on the thermoelectric properties of half-Heusler TiNiSn[J],2018,11(2).
APA	Tang Y..,Li X..,Martin L.H.J..,Cuervo Reyes E..,Ivas T..,...&Battaglia C..(2018).Impact of Ni content on the thermoelectric properties of half-Heusler TiNiSn.Energy & Environmental Science,11(2).
MLA	Tang Y.,et al."Impact of Ni content on the thermoelectric properties of half-Heusler TiNiSn".Energy & Environmental Science 11.2(2018).