Thermoelectric properties of CoSb3

Kawaharada, Yoshiyuki; Kurosaki, Ken; Uno, Masayoshi; Yamanaka, Shinşuke

doi:10.1016/s0925-8388(00)01275-5

Cited by 223 publications

(175 citation statements)

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“…This is in contrast to typical semiconductors, such as silicon, and leads to a p-type intrinsic semiconductor with a very low level of n-doping. The change of the major charge-carrier type, starting with n-type and showing a transition to p-type at 460 K agrees with earlier reports by Kawaharada et al [5] Figure 6 shows that the electrical conductivity, a, decreases with increasing temperature for all samples except for the reference. [27] The nanostructured materials studied here are all heavily doped p-type semiconductors, as can be seen by the low Seebeck coefficients and reasonably high electrical conductivities considering the grain size.…”

Section: Full Papersupporting

confidence: 90%

“…[21] Samples having smaller particle size have much lower k values, where k increases with increasing particle size. The sample HT1, with smallest particle size, has a thermal conductivity of 1.5 W m ±1 K ±1 at 320 K, which is about one order of magnitude lower than the value reported by Kawaharada et al [5] …”

Section: Full Papercontrasting

confidence: 53%

“…Many studies on CoSb 3 have reported a p-type behavior with a positive sign of the Seebeck coefficient. [3,5,10] The observed magnitude of the Seebeck coefficient is a result of the doping level of the samples. A high carrier concentration yields a low Seebeck coefficient and high electrical conductivity.…”

Section: Full Papermentioning

confidence: 99%

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The Impact of Nanostructuring on the Thermal Conductivity of Thermoelectric CoSb₃

Toprak¹,

Stiewe

Platzek

et al. 2004

Adv Funct Materials

283

190

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The high concentration of grain boundaries provided by nanostructuring is expected to lower the thermal conductivity of thermoelectric materials, which favors an increase in their thermoelectric figure‐of‐merit, ZT. A novel chemical alloying method has been used for the synthesis of nanoengineered‐skutterudite CoSb3. The CoSb3 powders were annealed for different durations to obtain a set of samples with different particle sizes. The samples were then compacted into pellets by uniaxial pressing under various conditions and used for the thermoelectric characterization. The transport properties were investigated by measuring the Seebeck coefficient and the electrical and thermal conductivities in the temperature range 300 K to 650 K. A substantial reduction in the thermal conductivity of CoSb3 was observed with decreasing grain size in the nanometer region. For an average grain size of 140 nm, the thermal conductivity was reduced by almost an order of magnitude compared to that of a single crystalline or highly annealed polycrystalline material. The highest ZT value obtained was 0.17 at 611 K for a sample with an average grain size of 220 nm. The observed decrease in the thermal conductivity with decreasing grain size is quantified using a model that combines the macroscopic effective medium approaches with the concept of the Kapitza resistance. The compacted samples exhibit Kapitza resistances typical of semiconductors and comparable to those of Si–Ge alloys.

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Section: Full Papersupporting

confidence: 90%

Section: Full Papercontrasting

confidence: 53%

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The Impact of Nanostructuring on the Thermal Conductivity of Thermoelectric CoSb₃

Toprak¹,

Stiewe

Platzek

et al. 2004

Adv Funct Materials

283

190

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“…2(a), the MD predicted L ð$1:0 W=m-KÞ and the two-phase scattering model show a minimum near x ¼ 0:38, and this minimum is close to min , predicted for the amorphous-phase L . Figure 2(b) shows the predicted L for x ¼ 0, 0.25, 0.33, and 0.5, as a function of temperature, along with the experimental results [32]. The transition temperatures (T and T ) of two ordered phases are marked in Fig.…”

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confidence: 81%

Structural Order-Disorder Transitions and Phonon Conductivity of Partially Filled Skutterudites

et al. 2010

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Filled skutterudites are high-performance thermoelectric materials and we show how their phonon conductivity is greatly influenced by the topology of the filler species. We predict (ab initio) the phase diagram of Ba x Co 4 Sb 12 and find several stable configurations of Ba ordering over the intrinsic voids. The phonon conductivity predicted using molecular dynamics shows a minimum in the two-phase mixture regime, dominated by significantly reduced long-range acoustic phonon transport. Binary skutterudites are compounds with the general formula MX 3 (M ¼ Co, Rh, Ir and X ¼ P, As, Sb) having a crystal structure with a bcc lattice and belonging to the space group Im3. The structure consists of a periodic array of trigonally distorted and tilted MX 6 octahedrons. The metal M at the center is octahedrally coordinated by the pnicogen X [13]. The tilt of the MX 6 octahedrons gives rise to empty spaces (icosahedral voids) that form a bodycentered sublattice. As first shown in [14], the voids are large enough and can be filled by foreign species entering as cations; however, the filler solubility limit is less than a full filling of all available voids [4,15].Binary skutterudites possess very high charge carrier mobilities and the interest in these compounds as novel TE materials for power generation followed a suggestion [16] and observation [11] that their L can be dramatically reduced upon filling the structural voids. Recent research has resulted in the TE figure of merit (ZT) of n-type skutterudites approaching the value of 1.5 at 800 K [17]. While the presence of the filler species in the skutterudite matrix seems to be essential for achieving low L and hence high ZT, whether the filler acts as a rattling local vibration mode [1][2][3][4] or plays some other important role [7,[18][19][20] remains controversial. So far the only insight into the role of ordered phases on the L of partially-filled skutterudites has been the observation in [3] that the random distribution of filler ions scatter phonons more effectively than when most voids are filled. In this letter, we address the issue of ordering of the filler species, a topic that has not yet been explored and that has a great influence on phonon scattering. To this end we examine Ba x Co 4 Sb 12 , a skutterudite with a large filling fraction limit for Ba, using theoretical and computational treatments.We begin with a determination of a temperaturecomposition phase diagram of Ba x Co 4 Sb 12 by combining ab initio calculations with the cluster expansion (CE) method and the Monte Carlo (MC) simulations. Thereafter, using equilibrium molecular dynamics (MD) simulations and the Green-Kubo fluctuation-dissipation linear response theory and L decomposition, along with the phase diagram, we predict the L of partially filled Ba x Co 4 Sb 12 as a function of concentration and temperature.A prediction of phase stability at finite temperature requires the use of statistical mechanics to account for entropic contributions to the free energy. The most important source of entr...

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“…The performance of TE materials is generally characterized by the dimensionless figure-of-merit [4,5]:…”

Section: Introductionmentioning

confidence: 99%

Thermoelectric properties of Ni_0.15Co_3.85Sb₁₂ and Fe_0.2Ni_0.15Co_3.65Sb₁₂ skutterudites prepared by HPHT method

Kong

Zhang

et al. 2017

Materials Science-Poland

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Thermoelectric properties of CoSb3

Cited by 223 publications

References 4 publications

The Impact of Nanostructuring on the Thermal Conductivity of Thermoelectric CoSb₃

The Impact of Nanostructuring on the Thermal Conductivity of Thermoelectric CoSb₃

Structural Order-Disorder Transitions and Phonon Conductivity of Partially Filled Skutterudites

Thermoelectric properties of Ni_0.15Co_3.85Sb₁₂ and Fe_0.2Ni_0.15Co_3.65Sb₁₂ skutterudites prepared by HPHT method

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Thermoelectric properties of CoSb3

Cited by 223 publications

References 4 publications

The Impact of Nanostructuring on the Thermal Conductivity of Thermoelectric CoSb3

The Impact of Nanostructuring on the Thermal Conductivity of Thermoelectric CoSb3

Structural Order-Disorder Transitions and Phonon Conductivity of Partially Filled Skutterudites

Thermoelectric properties of Ni0.15Co3.85Sb12 and Fe0.2Ni0.15Co3.65Sb12 skutterudites prepared by HPHT method

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The Impact of Nanostructuring on the Thermal Conductivity of Thermoelectric CoSb₃

The Impact of Nanostructuring on the Thermal Conductivity of Thermoelectric CoSb₃

Thermoelectric properties of Ni_0.15Co_3.85Sb₁₂ and Fe_0.2Ni_0.15Co_3.65Sb₁₂ skutterudites prepared by HPHT method