Nanophase oxalate precursors of thermoelectric CoSb3 by controlled coprecipitation predicted by thermodynamic modeling

Kim, Se Hoon; Kim, Min Cheol; Kim, Minsuk; Ahn, Jong Pil; Moon, Kyoung-Sook; Koo, Sang Man; Tafti, Mohsen Yakhshi; Park, Joo-Seok; Toprak, Muhammet S.; Lee, Byung-Ha; Kim, Do Kyung

doi:10.1016/j.apt.2016.03.006

Cited by 6 publications

(4 citation statements)

References 22 publications

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“…The decrease in κ is mainly due to the fact that the high-density nano-interfaces in the low dimensional materials enhance significantly the scattering of electrons and phonons. In the past ten years, TE properties of CoSb 3 materials have been improved significantly by the nanocrystallization of CoSb 3 -based materials [124][125][126][127][128][129][130][131][132][133][134][135][136][137][138][139][140] or the preparation of thin film materials [141][142][143][144][145][146][147]. Toprak et al [125] reported a novel chemical alloying method to prepare CoSb 3 materials with different nanoparticle sizes.…”

Section: Optimization At Atomic-molecular Scalementioning

confidence: 99%

A review of CoSb3-based skutterudite thermoelectric materials

et al. 2020

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The binary skutterudite CoSb3 is a narrow bandgap semiconductor thermoelectric (TE) material with a relatively flat band structure and excellent electrical performance. However, thermal conductivity is very high because of the covalent bond between Co and Sb, resulting in a very low ZT value. Therefore, researchers have been trying to reduce its thermal conductivity by the different optimization methods. In addition, the synergistic optimization of the electrical and thermal transport parameters is also a key to improve the ZT value of CoSb3 material because the electrical and thermal transport parameters of TE materials are closely related to each other by the band structure and scattering mechanism. This review summarizes the main research progress in recent years to reduce the thermal conductivity of CoSb3-based materials at atomic-molecular scale and nano-mesoscopic scale. We also provide a simple summary of achievements made in recent studies on the non-equilibrium preparation technologies of CoSb3-based materials and synergistic optimization of the electrical and thermal transport parameters. In addition, the research progress of CoSb3-based TE devices in recent years is also briefly discussed.

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Section: Optimization At Atomic-molecular Scalementioning

confidence: 99%

A review of CoSb3-based skutterudite thermoelectric materials

et al. 2020

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“…Controlling the temperature and time of the reduction, as well as the initial stoichiometry, leads to different final compositions, grain sizes, porosities and the overall thermoelectric properties of the material. Reduction in hydrogen was also used as part of a CoSb 3 chemical alloying fabrication process by Khan et al [36] and chemical co-precipitation by Kim et al [37]; however, the porosities of the obtained materials were relatively low (\ 10%). Other thermoelectric materials with slightly higher porosity (* 14%) were recently reported [38,39], and in both cases, significant enhancement of the ZT parameter was observed due to the presence of pores.…”

Section: Graphic Abstract Introductionmentioning

confidence: 99%

New synthesis route of highly porous InxCo4Sb12 with strongly reduced thermal conductivity

et al. 2020

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Highly porous, In-filled CoSb 3 skutterudite materials with an attractive thermoelectric figure of merit (ZT * 1) and corresponding dense samples were fabricated through the cost-effective method of reduction in oxides in dry hydrogen and the pulsed electric current sintering (PECS) method, respectively. The reduction process was described in detail using in situ thermogravimetric analysis of Co 2 O 3 , Sb 2 O 3 and In(NO 3) 3 Á5H 2 O separately and in a mixture. Two methods to synthesise the same material were examined: (a) free sintering of an initially reduced powder and (b) PECS. The free-sintered materials with higher porosities (up to * 40%) exhibited lower values of electrical conductivity than the dense PECS samples (porosity up to * 5%), but the benefit of an even sixfold reduction in thermal conductivity resulted in higher ZT values. The theoretical values of thermal conductivity for various effective media models considering randomly oriented spheroid pores are in good agreement with the experimental thermal conductivity data. The assumed distribution and shape of the pores correlated well with the scanning electron microscope analysis of the microstructure. The lowest value of thermal conductivity, equal to 0.5 W/m K, was measured at 523 K for In 0.1 Co 4 Sb 12 with 41% porosity. The highest value of ZT max = 1.0 at 673 K was found for the In 0.2 Co 4 Sb 12 sample in which the porosity was 36%.

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“…Previous synthesis routes for preparing CoSb3-based skutterudite were co-precipitation [19][20][21] , solvothermal, hydrothermal [22][23][24][25][26][27][28][29][30][31][32][33][34] , sol-gel [ 35] , modified polyol process [36][37][38] , ball milling or mechanical alloying and hot pressing [11,[39][40][41][42][43], melting-annealing-hot pressing or metallurgical route [12,[44][45][46], high pressure and high temperature (HPHT) [47][48][49], melt spinning and hot pressing [ 50] , and others. Liu and co-workers [ 11] synthesized CoSb3-xTex by using ball milling 15 h at 450 rpm and hot pressing under 50 MPa at 500°C for 5 min.…”

Section: Introductionmentioning

confidence: 99%

“…Almost all synthesis routes [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][39][40][41][42][43][44][45][46][47][48][49][50] need a long reaction time especially at high temperature and-/or high pressure. However, some chemical routes proceeded at low temperature with short reaction time which favors for all synthesis routes.…”

Section: Introductionmentioning

confidence: 99%

Application of Microwave Radiation in Modified Polyol Process for Synthesis Pure, Te-Doped, and Sn-Doped CoSb<sub>3</sub> Thermoelectric Materials

Kapanya

Thanachayanont

Tuantranont

et al. 2020

SSP

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Synthesis routes of CoSb3 need a long reaction time, especially at high temperature and-/or high pressure. Although the modified polyol process assisted with microwave radiation can be used to solve these problems, it used the excess amount of Sb ion. Therefore, this study aimed to solve this drawback by retarding the rate of reduction. The different microwave times (0, 1, and 3 min) were investigated to find out the shortest heating duration for preparing CoSb3 nanoparticles. Te-doped and Sn-doped CoSb3 were synthesized to investigate the benefit of this synthesis method for increasing the solubility limit of Te and Sn in the CoSb3 structure. The phase and microstructure of the synthesized products were characterized by using x-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The results showed that the high crystalline phase of CoSb3 (JCPDS: 78-0977) without any metallic impurity phases product was successfully synthesized in 3 minutes for a heating time at normal pressure, non-excessive addition of Sb ion precursor, and low temperature. The XRD results of Te-doped and Sn-doped CoSb3 products exhibited poor crystalline phase and hard to exactly identify. In SEM and TEM results, the CoSb3 powder consisted of very tiny spherical-like particles around 10 nanometers attaching together even at different microwave time similar to Te-doped/Sn-doped samples.

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Nanophase oxalate precursors of thermoelectric CoSb3 by controlled coprecipitation predicted by thermodynamic modeling

Cited by 6 publications

References 22 publications

A review of CoSb3-based skutterudite thermoelectric materials

A review of CoSb3-based skutterudite thermoelectric materials

New synthesis route of highly porous InxCo4Sb12 with strongly reduced thermal conductivity

Application of Microwave Radiation in Modified Polyol Process for Synthesis Pure, Te-Doped, and Sn-Doped CoSb<sub>3</sub> Thermoelectric Materials

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