Composition and the thermoelectric performance of β-Zn4Sb3

Toberer, Eric S.; Rauwel, Protima; Gariel, Sylvain; Taftø, J.; Snyder, G. Jeffrey

doi:10.1039/c0jm02011g

Cited by 140 publications

(115 citation statements)

References 37 publications

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“…Studies of ZnSb have been limited by its high thermal conductivity. 64,65 However, our facile, low-temperature solution-phase synthesis could be useful as a means of mitigating this problem, as it allows for reduction in grain size or nanostructuring. 13,[66][67][68][69] Characterization of LiZnSb using solid state NMR.…”

Section: Resultsmentioning

confidence: 99%

Expanding the I–II–V Phase Space: Soft Synthesis of Polytypic Ternary and Binary Zinc Antimonides

et al. 2018

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Soft chemistry methods offer the possibility of synthesizing metastable and kinetic products that are unobtainable through thermodynamically-controlled, high-temperature reactions. A recent solution-phase exploration of Li-Zn-Sb phase space revealed a previously unknown cubic half-Heusler MgAgAs-type LiZnSb polytype. Interestingly, this new cubic phase was calculated to be the most thermodynamically stable, despite prior literature reporting only two other ternary phases (the hexagonal half-Heusler LiGaGe-type LiZnSb, and the full-Heusler Li2ZnSb). This surprising discovery, coupled with the intriguing optoelectronic and transport properties of many antimony containing Zintl phases, required a thorough exploration of syn-thetic parameters. Here, we systematically study the effects that different precursor concentrations, injection order, nucleation and growth temperatures, and reaction time have on the solution-phase synthesis of these materials. By doing so, we identify conditions that selectively yield several unique ternary (c-LiZnSb vs. h*-LiZnSb), binary (ZnSb vs. Zn8Sb7), and metallic (Zn, Sb) products. Further, we find one of the ternary phases adopts a variant of the previously observed hexagonal LiZnSb struc-ture. Our results demonstrate the utility of low temperature solution phase-soft synthesis-methods in accessing and mining a rich phase space. We anticipate that this work will motivate further exploration of multinary I-II-V compounds, as well as encourage similarly thorough investigations of related Zintl systems by solution phase methods. Disciplines Materials ChemistryComments "This document is the unedited Author's version of a Submitted Work that was subsequently accepted for publication in Chemistry of Materials, copyright © American Chemical Society after peer review. To access the final edited and published work see http://dx.doi.org/10.1021/acs.chemmater.8b02910. ABSTRACT: Soft chemistry methods offer the possibility of synthesizing metastable and kinetic products that are unobtainable through thermodynamically-controlled, high-temperature reactions. A recent solution-phase exploration of Li-Zn-Sb phase space revealed a previously unknown cubic half-Heusler MgAgAs-type LiZnSb polytype. Interestingly, this new cubic phase was calculated to be the most thermodynamically stable, despite prior literature reporting only two other ternary phases (the hexagonal half-Heusler LiGaGe-type LiZnSb, and the full-Heusler Li2ZnSb). This surprising discovery, coupled with the intriguing optoelectronic and transport properties of many antimony containing Zintl phases, required a thorough exploration of synthetic parameters. Here, we systematically study the effects that different precursor concentrations, injection order, nucleation and growth temperatures, and reaction time have on the solution-phase synthesis of these materials. By doing so, we identify conditions that selectively yield several unique ternary (c-LiZnSb vs. h*-LiZnSb), binary (ZnSb vs. Zn8Sb7), and metallic (Zn, Sb) products. Furt...

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Section: Resultsmentioning

confidence: 99%

Expanding the I–II–V Phase Space: Soft Synthesis of Polytypic Ternary and Binary Zinc Antimonides

et al. 2018

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“…In the superionic phase, cations exhibit liquid-like diffusivity [3,4] and this disordered nature typically results in a very low lattice thermal conductivity (<1 W m −1 K −1 ). Many of the superionic compounds, particularly those that are also good electric conductors, indeed show promising thermoelectric properties as exemplified by Cu 2 Se [1,5], Cu 2 S [6,7], Ag 2 Se [8,9], and Zn 4 Sb 3 [10]. Cation movement is seen to be suppressed with the addition of lithium.…”

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confidence: 87%

Enhanced stability and thermoelectric figure-of-merit in copper selenide by lithium doping

Kang

Pöhls

Aydemir

et al. 2017

Materials Today Physics

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Superionic thermoelectric materials have been shown to have high figure-ofmerits, leading to expectations for efficient high-temperature thermoelectric generators. These compounds exhibit extremely high cation diffusivity, comparable to that of a liquid, which is believed to be associated with the low thermal conductivity that makes superionic materials good for thermoelectrics. However, the superionic behavior causes cation migration that leads to device deterioration, being the main obstacle for practical applications. It has been reported that lithium doping in superionic Cu 2-x Se leads to suppression of the Cu ion diffusivity, but whether the material will retain the promising thermoelectric properties had not yet been investigated. Here, we report a maximum zT > 1.4 from Li 0.09 Cu 1.9 Se, which is higher than what we find in the undoped samples. The high temperature effective weighted mobility of the doped sample is found higher than Cu 2-x Se, while the lattice thermal conductivity remains similar. We find signatures of suppressed bipolar conduction due to an enlarged band gap. Our findings set forth a possible route for tuning the stability of superionic thermoelectric materials.Thermoelectric generators produce electrical energy from a heat flux through the device. Having been proven for their reliability from stable implementations in space missions, the technology is now drawing interest for terrestrial applications. For example, using thermoelectric technology to convert waste industrial heat into electricity could deliver a significant alleviation to the energy crisis. However, wide-spread use of the technology is limited by the energy conversion efficiency, which is bottlenecked by what thermoelectric materials can offer. The maximum efficiency obtainable from a material is characterized by the figure-of-merit:where S is the Seebeck coefficient, σ is electrical conductivity, and κ is thermal conductivity. Thermoelectric materials research is thus heavily focused on the search for high zT materials. In the search for new material families for thermoelectrics, the revisit to superionic compounds as thermoelectric materials [1] has sparked great interest because of their inherently low thermal conductivity [2] which is advantageous in obtaining a high zT . In the superionic phase, cations exhibit liquid-like diffusivity [3,4] and this disordered nature typically results in a very low lattice thermal conductivity (<1 W m −1 K −1 ). Many of the superionic compounds, particularly those that are also good electric conductors, indeed show promising thermoelectric properties as exemplified by Cu 2 Se [1,5]

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“…16 and 18) and YbCd 2Àx Zn x Sb 2 , both of which have zT values above unity at high temperatures. 11,[19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] Recently, Yb 9 Mn 4.2 Sb 9 was shown to have promising thermoelectric performance (zT ¼ 0.7 at 950 K) by Bux et al 17 The structure of Yb 9 M 4+x Sb 9 is shown in Fig. 1, where M can be Fig.…”

Section: Introductionmentioning

confidence: 99%

Thermoelectric properties of the Yb₉Mn_4.2−xZn_xSb₉solid solutions

et al. 2014

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a Yb 9 Mn 4.2 Sb 9 has been shown to have extremely low thermal conductivity and a high thermoelectric figure of merit attributed to its complex crystal structure and disordered interstitial sites. Motivated by previous work which shows that isoelectronic substitution of Mn by Zn leads to higher mobility by reducing spin disorder scattering, this study investigates the thermoelectric properties of the solid solution, Yb 9 Mn 4.2Àx Zn x Sb 9 (x ¼ 0, 1, 2, 3 and 4.2). Measurements of the Hall mobility at high temperatures (up to 1000 K) show that the mobility can be increased by more than a factor of 3 by substituting Zn into Mn sites. This increase is explained by the reduction of the valence band effective mass with increasing Zn, leading to a slightly improved thermoelectric quality factor relative to Yb 9 Mn 4.2 Sb 9 . However, increasing the Zn-content also increases the p-type carrier concentration, leading to metallic behavior with low Seebeck coefficients and high electrical conductivity. Varying the filling of the interstitial site in Yb 9 Zn 4+y Sb 9 (y ¼ 0.2, 0.3, 0.4 and 0.5) was attempted, but the carrier concentration ($10 21 cm À3 at 300 K) and Seebeck coefficients remained constant, suggesting that the phase width of Yb 9 Zn 4+y Sb 9 is quite narrow.

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Composition and the thermoelectric performance of β-Zn4Sb3

Cited by 140 publications

References 37 publications

Expanding the I–II–V Phase Space: Soft Synthesis of Polytypic Ternary and Binary Zinc Antimonides

Expanding the I–II–V Phase Space: Soft Synthesis of Polytypic Ternary and Binary Zinc Antimonides

Enhanced stability and thermoelectric figure-of-merit in copper selenide by lithium doping

Thermoelectric properties of the Yb₉Mn_4.2−xZn_xSb₉solid solutions

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Composition and the thermoelectric performance of β-Zn4Sb3

Cited by 140 publications

References 37 publications

Expanding the I–II–V Phase Space: Soft Synthesis of Polytypic Ternary and Binary Zinc Antimonides

Expanding the I–II–V Phase Space: Soft Synthesis of Polytypic Ternary and Binary Zinc Antimonides

Enhanced stability and thermoelectric figure-of-merit in copper selenide by lithium doping

Thermoelectric properties of the Yb9Mn4.2−xZnxSb9solid solutions

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Thermoelectric properties of the Yb₉Mn_4.2−xZn_xSb₉solid solutions