Material and manufacturing cost considerations for thermoelectrics

LeBlanc, Saniya; Yee, Shannon K.; Scullin, Matthew L.; Dames, Chris; Goodson, Kenneth E.

doi:10.1016/j.rser.2013.12.030

Cited by 428 publications

(298 citation statements)

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“…Thermoelectric (TE) materials, which have the capability of converting heat directly into electricity under a temperature gradient, have been regarded as an alternative option to alleviate energy shortage. 1 Though TE devices have already been applied in deep space exploration and solid state cooling, 2,3 the relatively low energy conversion efficiency limits their wide commercialization, 4 which is mainly constrained by the performance of TE materials as characterized by the dimensionless figure of merit, zT = α 2 σT/(κ e + κ L ), where α is the Seebeck coefficient, σ is the electrical conductivity, κ e and κ L are, respectively, the electronic and lattice contributions to the total thermal conductivity κ, and T is the absolute temperature. 5 Since all three physical properties (α, σ, and κ) are carrier concentration dependent, zT could reach its maximum value at an optimized carrier concentration.…”

Section: Introductionmentioning

confidence: 99%

Valleytronics in thermoelectric materials

et al. 2018

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The central theme of valleytronics lies in the manipulation of valley degree of freedom for certain materials to fulfill specific application needs. While thermoelectric (TE) materials rely on carriers as working medium to absorb heat and generate power, their performance is intrinsically constrained by the energy valleys to which the carriers reside. Therefore, valleytronics can be extended to the TE field to include strategies for enhancing TE performance by engineering band structures. This review focuses on the recent progress in TE materials from the perspective of valleytronics, which includes three valley parameters (valley degeneracy, valley distortion, and valley anisotropy) and their influencing factors. The underlying physical mechanisms are discussed and related strategies that enable effective tuning of valley structures for better TE performance are presented and highlighted. It is shown that valleytronics could be a powerful tool in searching for promising TE materials, understanding complex mechanisms of carrier transport, and optimizing TE performance.npj Quantum Materials (2018) 3:9 ; doi:10.1038/s41535-018-0083-6 INTRODUCTIONThe demand for renewable energy harvesting has been growing because of the limited fossil fuels and increasing worldwide energy consumption. Thermoelectric (TE) materials, which have the capability of converting heat directly into electricity under a temperature gradient, have been regarded as an alternative option to alleviate energy shortage.1 Though TE devices have already been applied in deep space exploration and solid state cooling, 2,3 the relatively low energy conversion efficiency limits their wide commercialization, 4 which is mainly constrained by the performance of TE materials as characterized by the dimensionless figure of merit, zT = α 2 σT/(κ e + κ L ), where α is the Seebeck coefficient, σ is the electrical conductivity, κ e and κ L are, respectively, the electronic and lattice contributions to the total thermal conductivity κ, and T is the absolute temperature.5 Since all three physical properties (α, σ, and κ) are carrier concentration dependent, zT could reach its maximum value at an optimized carrier concentration. zT max is determined by a combination of intrinsic physical parameters as well as the temperature, all of which integrated into a term called the TE quality factor, B. Higher quality factor B leads to higher zT max at a fixed temperature. With a single parabolic band model in the nondegenerate limit, B could be expressed as:

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Section: Introductionmentioning

confidence: 99%

Valleytronics in thermoelectric materials

et al. 2018

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“…[17] More recently, the ZT values of conventional thermoelectric materials have been significantly improved to new records in the laboratory through nanotechnology, chemical doping, and engineering of electronic structure. [14][15][16][17][18][19][20] For example, a ZT of 2.4 for Bi-Sb-Te superlattice was achieved at 300 K, and a ZT of 2.2 for Sr-, Na-doped bulk PbTe was realized at 915 K. [14,17] I-doped bulk Cu2Se exhibited a ZT of 2.3 at 400 K, [18] and its analogue Cu2S had a ZT of 0.5 at 673 K. [19] The high ZT and low cost of metal chalcogenides make them very promising in heat conversion. [20] It has been demonstrated that the improvement of ZT in most metal chalcogenides in recent reports is attributable to the introduction of nano-precipitates (or nanograins), which can effectively decrease their thermal conductivity.…”

Section: Introductionmentioning

confidence: 99%

“…[14][15][16][17][18][19][20] For example, a ZT of 2.4 for Bi-Sb-Te superlattice was achieved at 300 K, and a ZT of 2.2 for Sr-, Na-doped bulk PbTe was realized at 915 K. [14,17] I-doped bulk Cu2Se exhibited a ZT of 2.3 at 400 K, [18] and its analogue Cu2S had a ZT of 0.5 at 673 K. [19] The high ZT and low cost of metal chalcogenides make them very promising in heat conversion. [20] It has been demonstrated that the improvement of ZT in most metal chalcogenides in recent reports is attributable to the introduction of nano-precipitates (or nanograins), which can effectively decrease their thermal conductivity. Although most metal chalcogenide nanostructures could be synthesized via ball milling in large scale, [7][8]11,[13][14][21][22] this process is time-consuming, and the resultant nanostructures have a broad size distribution.…”

Section: Introductionmentioning

confidence: 99%

Robust scalable synthesis of surfactant-free thermoelectric metal chalcogenide nanostructures

Han

et al. 2015

Nano Energy

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, S. Xue. (2015). Robust scalable synthesis of surfactant-free thermoelectric metal chalcogenide nanostructures. Nano Energy, Robust scalable synthesis of surfactant-free thermoelectric metal chalcogenide nanostructures AbstractA robust low-cost ambient aqueous method for the scalable synthesis of surfactant-free nanostructured metal chalcogenides (MaXb, M=Cu, Ag, Sn, Pb, and Bi; X=S, Se, and Te; a=1 or 2; and b=1 or 3) is developed in this work. The effects of reaction parameters, such as precursor concentration, ratio of precursors, and amount of reducing agent, on the composition, size, and shape of the resultant nanostructures have been comprehensively investigated. This environmentally friendly approach is capable of producing metal chalcogenide nanostructures in a one-pot reaction on a large scale, which were investigated for their thermoelectric properties towards conversion of waste heat into electricity. The results demonstrate that the thermoelectric properties of these metal chalcogenide nanostructures are strongly dependent on the types of metal chalcogenides, and their figure of merits are comparable with previously reported figures for their bulk or nanostructured counterparts.

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“…9,10 Recently, ultralow thermal conductivities of 0.4-0.5 Wm -1 K -1 resulting from bonding anharmonicity where weakly bound cations act as rattlers were observed in metal tellurides. 11,12 As part of the search for materials based on less toxic and/or scarce components 13,14 that can operate under more demanding conditions including the broad temperature ranges required for some applications (automotive exhaust waste heat recovery: 350-700 K, industrial furnace waste heat recovery: 700-1100 K), 15,16 there is growing interest in thermoelectric oxides. 17,18 However, the strategies used to design high-performance thermoelectric materials based on small band gap, broad-band semiconductors and intermetallics cannot be translated directly to oxide materials.…”

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confidence: 99%

Phonon-glass electron-crystal behaviour by A site disorder in n-type thermoelectric oxides

Daniels

Саввин

Pitcher

et al. 2017

Energy Environ. Sci.

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a Phonon-glass electron-crystal (PGEC) behaviour is realised in La0.5Na0.5Ti1-xNbxO3 thermoelectric oxides. The vibrational disorder imposed by the presence of both La 3+ and Na + cations on the A site of the ABO3 perovskite oxide La0.5Na0.5TiO3 produces a phonon-glass with a thermal conductivity, κ, 80% lower than that of SrTiO3 at room temperature. Unlike other state-of-the-art thermoelectric oxides, where there is strong coupling of κ to the electronic power factor, the electronic transport of these materials can be optimised independently of the thermal transport through cation substitution at the octahedral B site. The low κ of the phonon-glass parent is retained across the La0.5Na0.5Ti1-xNbxO3 series without disrupting the electronic conductivity, affording PGEC behaviour in oxides.Thermoelectric generators offer enhanced energy efficiency across the industrial and automotive sectors through the conversion of waste heat into electricity. Materials performance is assessed by the dimensionless figure of merit ZT = (S 2 σ/κ)T, combining the thermal conductivity (κ), absolute temperature (T), the Seebeck coefficient (S) and electrical conductivity (σ), which together define the power factor (S 2 σ). One strategy to optimise ZT is the phononglass electron-crystal (PGEC) concept proposed by Slack, 1 which aims to decouple the quantities governed by the Boltzmann transport equation in an "electron-crystal", by maximising S and σ, from the quantity governed by phonon transport processes in a "phonon-glass" (PG) by minimising the lattice contribution to the thermal conductivity (κlatt); essentially, a crystal that transports charge like a semiconductor, whilst hindering the transport of heat by the lattice like a glass. 2 Heat transport in solids consists of lattice and electronic (κelec) contributions through κ = κlatt + κelec, and κlatt=1/3Cv·lph·νs (Equation 1), where Cv is the isochoric heat capacity, lph the average phonon mean free path (MFP), and vs the mean velocity of sound. Different heat-carrying mechanisms lead to a broad distribution of MFPs, ranging from the atomic scale (<1 nm) for point defect scattering, to the mesoscale (>100 nm) for grain boundary scattering. In a "phonon-crystal" (PC), heat is transported by phonons of well-defined wavelength. The phonon scattering rate (ph -1 ), which is inversely proportional to κlatt (Equation S1, ESI †), corresponds to the sum of the inverse relaxation times of several phonon-scattering mechanisms that contribute separately to κ and is described quantitatively by the modified Debye-Callaway model (Equation S3, ESI †). 3 This produces a T -1 temperature dependence of κ above the Debye temperature (D) where heat conduction is by Oxide materials are of current interest as high-temperature energy-harvesting thermoelectrics in the automotive and manufacturing sectors due to their low cost, low toxicity and high chemical robustness. The phonon-glass electron crystal (PGEC) concept which has been successfully used to optimise the thermoelectric figure of merit (Z...

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Material and manufacturing cost considerations for thermoelectrics

Cited by 428 publications

References 60 publications

Valleytronics in thermoelectric materials

Valleytronics in thermoelectric materials

Robust scalable synthesis of surfactant-free thermoelectric metal chalcogenide nanostructures

Phonon-glass electron-crystal behaviour by A site disorder in n-type thermoelectric oxides

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