Thermoelectric Properties of Mechanically-Alloyed and Hot-Pressed Cu12−xCoxSb4S13 Tetrahedrites

Kim, Sung-Yoon; Lee, Go-Eun; Kim, Il-Ho

doi:10.3938/jkps.74.967

Cited by 19 publications

(14 citation statements)

References 13 publications

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“…As mentioned in our description of the experimental method, because the energy levels of Bi and S used in the EDS analysis are similar, measurement errors might be high. However, in our previous studies[12][13][14] on non-doped and doped tetrahedrites prepared by the same MA-HP process, the actual compositions were similar to the nominal compositions.…”

mentioning

confidence: 77%

Solid-State Synthesis and Thermoelectric Properties of Tetrahedrites Cu12Sb4-yBiyS13

Kwak¹,

Pi²,

Lee³

et al. 2020

Korean J. Met. Mater.

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Tetrahedrite has low lattice thermal conductivity because of the lone-pair electrons of Sb, which cause the Cu atoms to vibrate at a low frequency and high amplitude. The synthesis of tetrahedrite compounds by conventional melting methods requires a long-time reaction and annealing. However, a homogeneous and solid-state synthesis can be conducted in a short time using mechanical alloying (MA) because the volatilization of the constituent elements is inhibited and a subsequent heat treatment is not necessary. In this study, Bi-doped tetrahedrites Cu12Sb4-yBiyS13 (y = 0-0.4) were prepared by MA and hot pressing. X-ray diffraction analyses revealed that all specimens consisted of single-phase tetrahedrite. However, with increasing Bi content, skinnerite Cu3SbS3 was detected. The electrical conductivity increased and the Seebeck coefficient deceased with increasing Bi content as result of the substitution of Bi at Sb sites. In addition, the thermal conductivity increased as the Bi content increased because of the increase in electronic thermal conductivity. A high dimensionless figure of merit of 0.88 was obtained at 723 K for Cu12Sb3.9Bi0.1S13.

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confidence: 77%

Solid-State Synthesis and Thermoelectric Properties of Tetrahedrites Cu12Sb4-yBiyS13

Kwak¹,

Pi²,

Lee³

et al. 2020

Korean J. Met. Mater.

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“…Considering the valence and coordination of each element, the charge balance of tetrahedrite can be expressed as [6,7]. To improve the dimensionless figure of merit (ZT), partial substitutions at the Cu, Sb, or S sites have been made with doping elements, including transition metals such as Ni, Co, Fe, and Mn at the Cu site [8][9][10][11], Te or As at the Sb site [12,13], and Se at the S site [14].…”

Section: Introductionmentioning

confidence: 99%

Charge Transport and Thermoelectric Properties of Sn-Doped Tetrahedrites Cu12Sb4-ySnyS13

Ahn¹,

Kim²

2021

Korean J. Met. Mater.

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In this study, tetrahedrite compounds doped with Sn were prepared by mechanical alloying and hot pressing, and their charge transport and thermoelectric properties were analyzed. X-ray diffraction analysis revealed that both the synthetic powders and sintered bodies were synthesized as a single tetrahedrite phase without secondary phases. Densely sintered specimens were obtained with relatively high densities of 99.5%-100.0% of the theoretical density, and the component elements were distributed uniformly. Sn was successfully substituted at the Sb site, and the lattice constant increased from 1.0348 to 1.0364 nm. Positive signs of the Hall and Seebeck coefficients confirmed that the Sn-doped tetrahedrites were p-type semiconductors. The carrier concentration decreased from 1.28 × 1019 to 1.57 × 1018 cm-3 as the Sn content decreased because excess electrons were supplied by doping with Sn4+ at the Sb3+ site of the tetrahedrite. The Seebeck coefficient increased with increasing Sn content, and Cu12Sb3.6Sn0.4S13 exhibited maximum values of 238-270 µVK-1 at temperatures of 323-723 K. However, the electrical conductivity decreased as the amount of Sn doping increased. Thus, Cu12Sb3.9Sn0.1S13 exhibited the highest electrical conductivity of (2.24-2.40) × 104 Sm-1 at temperatures of 323-723 K. A maximum power factor of 0.73 mWm-1K-2 was achieved at 723 K for Cu12Sb3.9Sn0.1S13. Sn substitution reduced both the electronic and lattice thermal conductivities. The lowest thermal conductivity of 0.49-0.60 Wm-1K-1 was obtained at temperatures of 323-723 K for Cu12Sb3.6Sn0.4S13, where the lattice thermal conductivity was dominant at 0.49-0.57 Wm-1K-1. As a result, a maximum dimensionless figure of merit of 0.66 was achieved at 723 K for Cu12Sb3.9Sn0.1S13.

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“…In order to consider rare-earth zirconates, or any other compound, as good prospects for thermoelectric applications, they must satisfy specific characteristics in their thermoelectric performance. The materials must have high electrical conductivity (from 0.01 to 0.6 S/cm), a high Seebeck coefficient (from 130 to 225 µV/K), and low thermal conductivity (from 0.5 to 0.75 W/mK) [12][13][14][15]. One of the important properties of the rare-earth zirconates that might offer a better figure of merit ZT is their low thermal conductivity.…”

Section: Introductionmentioning

confidence: 99%

Electrical and thermal conductivities of rare-earth A2Zr2O7 (A = Pr, Nd, Sm, Gd, and Er)

et al. 2021

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Structural and thermoelectric properties of rare-earth zirconates A2Zr2O7, with A = Pr, Nd, Sm, Gd, and Er, were studied. Samples were prepared by solid-state reaction at ambient pressure with temperatures between 1000 and 1400 °C. The resulting compounds were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM/EDS). The XRD analyses showed the formation of polycrystalline Pr2Zr2O7, Nd2Zr2O7, Sm2Zr2O7, Gd2Zr2O7 and Er2Zr2O7 phases, with a cubic cell (space group Fm3m) and traces of the raw used materials. The micrographs obtained by SEM show the formation of heterogeneous grains with a size that ranges from 0.7 to 4.7 μm. All A2Zr2O7 samples present porous surfaces. Thermal conductivities were measured at different temperatures, from 300 to 900 K. In most of the samples, the thermal conductivity monotonically decreases with temperature, from 0.40 – 1.17 W/mK at 300 K to 0.27 – 0.77 W/mK at 773.15 K. At a fixed temperature, the thermal conductivity decreases almost monotonically with the ionic radius (IR) of the rare-earth elements (where IR (Er3+) = 0.890 Å < IR (Gd3+) = 0.938 Å < IR (Sm3+) = 0.958 Å < IR (Nd3+) = 0.983 Å < IR (Pr3+) = 0.99 Å).

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Thermoelectric Properties of Mechanically-Alloyed and Hot-Pressed Cu12−xCoxSb4S13 Tetrahedrites

Cited by 19 publications

References 13 publications

Solid-State Synthesis and Thermoelectric Properties of Tetrahedrites Cu12Sb4-yBiyS13

Solid-State Synthesis and Thermoelectric Properties of Tetrahedrites Cu12Sb4-yBiyS13

Charge Transport and Thermoelectric Properties of Sn-Doped Tetrahedrites Cu12Sb4-ySnyS13

Electrical and thermal conductivities of rare-earth A2Zr2O7 (A = Pr, Nd, Sm, Gd, and Er)

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