Thermal conductivity of skutterudite CoSb3 from first principles: Substitution and nanoengineering effects

Guo, Ruiqiang; Wang, Xinjiang; Huang, Baoling

doi:10.1038/srep07806

Cited by 74 publications

(49 citation statements)

References 58 publications

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“…24 These calculated values are in good agreement with the previously published theoretical value of 9.14 Å for CoSb 3 and 5.89 Å for TiCoSb. [25][26][27] To determine the favorable surface slab, we calculated the surface energy, γ , from the following expression, 28 A is the surface area.…”

Section: Methodsmentioning

confidence: 99%

Structure and Failure Mechanism of the Thermoelectric CoSb₃/TiCoSb Interface

Hao

Aydemir

et al. 2016

ACS Appl. Mater. Interfaces

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Abstract:The brittle behavior and low strength of CoSb 3 /TiCoSb interface are serious issues concerning the engineering applications of CoSb 3 based or CoSb 3 /TiCoSb segmented thermoelectric devices. To illustrate the failure mechanism of the CoSb 3 /TiCoSb interface, we apply density functional theory to investigate the interfacial behavior and examine the response during tensile deformations. We find that both CoSb 3 (100)/TiCoSb(111) and CoSb 3 (100)/TiCoSb(110) are energetically favorable interfacial structures. Failure of the CoSb 3 /TiCoSb interface occurs in CoSb 3 since the structural stiffness of CoSb 3 is much weaker than that of TiCoSb. This failure within CoSb 3 can be explained through the softening of the Sb−Sb bond along with the cleavage of the Co−Sb bond in the interface. The failure mechanism the CoSb 3 /TiCoSb interface is similar to that of bulk CoSb 3 , but the ideal tensile strength and failure strain of the CoSb 3 /TiCoSb interface are much lower than those of bulk CoSb 3 . This can be attributed to the weakened stiffness of the Co−Sb framework due to structural rearrangement near the interfacial region.

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Section: Methodsmentioning

confidence: 99%

Structure and Failure Mechanism of the Thermoelectric CoSb₃/TiCoSb Interface

Hao

Aydemir

et al. 2016

ACS Appl. Mater. Interfaces

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“…112 Only compounds with long MFPs of phonons, such as Si or SiGe alloys, half-Heusler alloys, and skutterudites, can sufficiently take the benefits from the nanostructures. Furthermore, owing to the decreasing of MFP of phonons as the temperature increases (Figure 7b), 109,111 the effect on the κ L from the interface scattering will diminish at higher temperatures.…”

Section: From the Conventional Phonon-phonon Interactions To Nanostrumentioning

confidence: 99%

“…Yang et al calculated the room temperature values of the electron de Broglie wavelength λ, 110 and the values of λ for degenerate compounds fall within a narrow range (⩽5 nm). The phonon mean-free paths, if we define the mean values corresponding to 50 % κ L reduction, 111 vary by 2-3 orders of magnitude according to ab initio IFC calculations. 94,102,[105][106][107][108] Usually, low κ L materials have low MFPs, sometimes even lower than the effective length of charge carriers.…”

Section: From the Conventional Phonon-phonon Interactions To Nanostrumentioning

confidence: 99%

On the tuning of electrical and thermal transport in thermoelectrics: an integrated theory–experiment perspective

et al. 2016

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During the last two decades, we have witnessed great progress in research on thermoelectrics. There are two primary focuses. One is the fundamental understanding of electrical and thermal transport, enabled by the interplay of theory and experiment; the other is the substantial enhancement of the performance of various thermoelectric materials, through synergistic optimisation of those intercorrelated transport parameters. Here we review some of the successful strategies for tuning electrical and thermal transport. For electrical transport, we start from the classical but still very active strategy of tuning band degeneracy (or band convergence), then discuss the engineering of carrier scattering, and finally address the concept of conduction channels and conductive networks that emerge in complex thermoelectric materials. For thermal transport, we summarise the approaches for studying thermal transport based on phonon-phonon interactions valid for conventional solids, as well as some quantitative efforts for nanostructures. We also discuss the thermal transport in complex materials with chemical-bond hierarchy, in which a portion of the atoms (or subunits) are weakly bonded to the rest of the structure, leading to an intrinsic manifestation of part-crystalline part-liquid state at elevated temperatures. In this review, we provide a summary of achievements made in recent studies of thermoelectric transport properties, and demonstrate how they have led to improvements in thermoelectric performance by the integration of modern theory and experiment, and point out some challenges and possible directions. INTRODUCTION Thermoelectric (TE) materials are materials that can generate useful electric potentials when subjected to a temperature gradient (known as the Seebeck effect). Conversely, they also transfer heat against the temperature gradient when a current is driven against this potential (known as the Peltier effect). They are promising energy materials with many applications, such as waste heat harvesting, radioisotope TE power generation, and solid state Peltier refrigeration, all of which are driving growing research interest. A key challenge is to improve the TE properties in order to obtain more efficient energy conversion and in turn enable new practical applications. Good TE materials must have excellent electrical transport properties, measured by the TE power factor ( = S 2 σ, where S is the Seebeck coefficient and σ is the electrical conductivity), and also a very low thermal conductivity κ (composed of the electronic contribution κ e , the lattice contribution κ L , and the bipolar contribution κ bi ). Combining the two aspects gives us the dimensionless figure of merit ZT,

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“…[13][14][15][16][17] Those phonons are primarily scattered by features in the structure (dopant, nanostructures and so on) that are comparable in size to the MFP of the phonons. For example, the high-frequency (short-wavelength) phonons tend to be scattered more effectively by atomic-scale point defects, that is, doping foreign species at the sites of Co 18,19 and Sb 7,11,20,21 or introducing filler atoms [22][23][24] into the structural voids (cages) of CoSb 3 .…”

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

Panoscopic approach for high-performance Te-doped skutterudite

Liang

Yan

et al. 2017

NPG Asia Mater

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One-step plasma-activated sintering (OS-PAS) fabrication of single-phase high-performance CoSb 3 -based skutterudite thermoelectric material with a hierarchical structure on a time scale of a few minutes is first reported here. The formation mechanism of the CoSb 3 phase and the effects of the current and pressure fields on the phase transformation and microstructure evolution are studied in the one-step PAS process. The application of the panoscopic approach to this system and its effect on the transport properties are investigated. The results show that the hierarchical structure forms during the formation of the skutterudite phase under the effects of both current and sintering pressure. The samples fabricated by the OS-PAS technique have defined hierarchical structures, which scatter phonons more intensely over a broader range of frequencies and significantly reduce the lattice thermal conductivity. High-performance bulk Te-doped skutterudite with the maximum ZT of 1.1 at 820 K for the composition CoSb 2.875 Te 0.125 was obtained. Such high ZT values rival those obtained from single filled skutterudites. This newly developed OS-PAS technique enhances the thermoelectric performance, dramatically shortens the synthesis period and provides a facile method for obtaining hierarchical thermoelectric materials on a large scale. NPG Asia Materials (2017) 9, e352; doi:10.1038/am.2017.1; published online 24 February 2017 INTRODUCTION Thermoelectric technology uses solid-state semiconductors, which can directly convert heat into electricity and vice versa using the Seebeck effect for power generation and Peltier effect for cooling. The efficiency of thermoelectric materials is governed by the dimensionless figure of merit ZT = α 2 σT/κ, where α, σ, T and κ are the Seebeck coefficient, electrical conductivity, absolute temperature and thermal conductivity, respectively. Many studies have been conducted in the past decades 1-5 to enhance the thermoelectric properties with a focus on improving the power factor and decreasing the thermal conductivity. Because of the high electrical transport performance 6,7 and relatively good mechanical properties, 8 skutterudites are considered notably promising for commercial power generation thermoelectric applications 9,10 in the temperature range of 500-900 K. 6,7,11,12 However, the disadvantage of skutterudites is their notably high lattice thermal conductivity of 410 W m − 1 K − 1 . To obtain a higher conversion efficiency, the thermal conductivity must be further reduced.The thermal conductivity of skutterudites derives from the contributions of phonons with a notably broad range of frequencies and mean free paths (MFPs). [13][14][15][16][17] Those phonons are primarily scattered by features in the structure (dopant, nanostructures and so on) that are comparable in size to the MFP of the phonons. For example, the high-frequency (short-wavelength) phonons tend to be scattered more

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Thermal conductivity of skutterudite CoSb3 from first principles: Substitution and nanoengineering effects

Cited by 74 publications

References 58 publications

Structure and Failure Mechanism of the Thermoelectric CoSb₃/TiCoSb Interface

Structure and Failure Mechanism of the Thermoelectric CoSb₃/TiCoSb Interface

On the tuning of electrical and thermal transport in thermoelectrics: an integrated theory–experiment perspective

Panoscopic approach for high-performance Te-doped skutterudite

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Thermal conductivity of skutterudite CoSb3 from first principles: Substitution and nanoengineering effects

Cited by 74 publications

References 58 publications

Structure and Failure Mechanism of the Thermoelectric CoSb3/TiCoSb Interface

Structure and Failure Mechanism of the Thermoelectric CoSb3/TiCoSb Interface

On the tuning of electrical and thermal transport in thermoelectrics: an integrated theory–experiment perspective

Panoscopic approach for high-performance Te-doped skutterudite

Contact Info

Product

Resources

About

Structure and Failure Mechanism of the Thermoelectric CoSb₃/TiCoSb Interface

Structure and Failure Mechanism of the Thermoelectric CoSb₃/TiCoSb Interface