scholarly journals α-Bi2Sn2O7: A Potential Room Temperature n-type Oxide Thermoelectric

2020 ◽  
Author(s):  
Warda Rahim ◽  
Jonathan Skelton ◽  
David Scanlon
Keyword(s):  
Thermal Conductivity ◽  
Low Temperature ◽  
Room Temperature ◽  
Lattice Thermal Conductivity ◽  
Phonon Transport ◽  
Consumer Electronics ◽  
Low Grade ◽  
Oxide Material ◽  
Thermoelectric Efficiency ◽  
Oxide Thermoelectrics

<p>Interest in oxide thermoelectrics has been building due to their high thermal stability and earth-abundant constituent elements. However, the thermoelectric efficiency of flagship oxide materials remains comparatively low, and most materials only reach the maximum figure of merit, <i>ZT</i>, at very high temperatures, above those where the majority of low-grade industrial heat is emitted. It is important to identify thermoelectrics with high conversion efficiency closer to room temperature, particularly for lower-temperature applications such as in domestic heating, consumer electronics and electric vehicles. One of the main factors limiting the efficiency of oxide thermoelectrics is their large lattice thermal conductivities, which has inspired research into more structurally complex materials. In this study, we apply first-principles modelling to assess the low-temperature polymorph of Bi<sub>2</sub>Sn<sub>2</sub>O<sub>7</sub> (α-Bi<sub>2</sub>Sn<sub>2</sub>O<sub>7</sub>) as a potential thermoelectric material, due to its complex crystal structure, which should suppress phonon transport, and the presence of Bi <i>p</i> and Sn <i>s</i> states in the conduction band, which should yield high electrical conductivity when donor (<i>n</i>) doped. Lattice-dynamics calculations using third-order perturbation theory predict an ultralow room-temperature lattice thermal conductivity of 0.4 W m<sup>-1</sup> K<sup>-1</sup>, the lowest ever predicted for an oxide material, and suggest that nanostructuring to a grain size of 5 nm could further decrease this to 0.28 W m<sup>-1</sup> K<sup>-1</sup>. The ultralow lattice thermal conductivity gives α-Bi<sub>2</sub>Sn<sub>2</sub>O<sub>7 </sub>a maximum <i>ZT</i> of 0.36 at 385 K (0.46 with nanostructuring), which is the highest low-temperature value predicted for an oxide thermoelectric. Most importantly, our analysis highlights the relationship between the structural complexity, the chemical nature of the cation, and the short phonon lifetimes, and thus provides guidelines for identifying other novel high-performance oxide thermoelectrics.</p>

scholarly journals α-Bi2Sn2O7: A Potential Room Temperature n-type Oxide Thermoelectric

2020 ◽  
Author(s):  
Warda Rahim ◽  
Jonathan Skelton ◽  
David Scanlon
Keyword(s):  
Thermal Conductivity ◽  
Low Temperature ◽  
Room Temperature ◽  
Lattice Thermal Conductivity ◽  
Phonon Transport ◽  
Consumer Electronics ◽  
Low Grade ◽  
Oxide Material ◽  
Thermoelectric Efficiency ◽  
Oxide Thermoelectrics

<p>Interest in oxide thermoelectrics has been building due to their high thermal stability and earth-abundant constituent elements. However, the thermoelectric efficiency of flagship oxide materials remains comparatively low, and most materials only reach the maximum figure of merit, <i>ZT</i>, at very high temperatures, above those where the majority of low-grade industrial heat is emitted. It is important to identify thermoelectrics with high conversion efficiency closer to room temperature, particularly for lower-temperature applications such as in domestic heating, consumer electronics and electric vehicles. One of the main factors limiting the efficiency of oxide thermoelectrics is their large lattice thermal conductivities, which has inspired research into more structurally complex materials. In this study, we apply first-principles modelling to assess the low-temperature polymorph of Bi<sub>2</sub>Sn<sub>2</sub>O<sub>7</sub> (α-Bi<sub>2</sub>Sn<sub>2</sub>O<sub>7</sub>) as a potential thermoelectric material, due to its complex crystal structure, which should suppress phonon transport, and the presence of Bi <i>p</i> and Sn <i>s</i> states in the conduction band, which should yield high electrical conductivity when donor (<i>n</i>) doped. Lattice-dynamics calculations using third-order perturbation theory predict an ultralow room-temperature lattice thermal conductivity of 0.4 W m<sup>-1</sup> K<sup>-1</sup>, the lowest ever predicted for an oxide material, and suggest that nanostructuring to a grain size of 5 nm could further decrease this to 0.28 W m<sup>-1</sup> K<sup>-1</sup>. The ultralow lattice thermal conductivity gives α-Bi<sub>2</sub>Sn<sub>2</sub>O<sub>7 </sub>a maximum <i>ZT</i> of 0.36 at 385 K (0.46 with nanostructuring), which is the highest low-temperature value predicted for an oxide thermoelectric. Most importantly, our analysis highlights the relationship between the structural complexity, the chemical nature of the cation, and the short phonon lifetimes, and thus provides guidelines for identifying other novel high-performance oxide thermoelectrics.</p>

scholarly journals α-Bi2Sn2O7: a potential room temperature n-type oxide thermoelectric

2020 ◽  
Vol 8 (32) ◽  
pp. 16405-16420 ◽  
Author(s):  
Warda Rahim ◽  
Jonathan M. Skelton ◽  
David O. Scanlon
Keyword(s):  
Thermal Conductivity ◽  
Low Temperature ◽  
Ab Initio ◽  
Room Temperature ◽  
Lattice Thermal Conductivity ◽  
Phonon Scattering ◽  
High Density ◽  
Earth Abundant ◽  
Scattering Events

Using ab initio methods, we predict α-Bi2Sn2O7 to have an ultra-low lattice thermal conductivity at room temperature due to the high density of phonon scattering events, which makes it a potential earth-abundant n-type low temperature thermoelectric.

scholarly journals Improvement of Thermoelectric Properties through Reduction of Thermal Conductivity by Nanoparticle Addition and Stoichiometric Change to Mg2Si

MRS Advances ◽  
2017 ◽  
Vol 2 (58-59) ◽  
pp. 3637-3643
Author(s):  
William T. Yorgason ◽  
Arden N. Barnes ◽  
Nick Roberts
Keyword(s):  
Thermal Conductivity ◽  
Lattice Thermal Conductivity ◽  
Phonon Scattering ◽  
Waste Heat ◽  
Mean Free Path ◽  
Phonon Transport ◽  
Thermoelectric Efficiency ◽  
Minimal Impact ◽  
Si Nanoparticle ◽  
Si Nanoparticles

ABSTRACT Thermoelectric materials have been of interest for several decades due to their ability to recapture waste heat of various systems and convert it to useful electricity. One method used to improve the thermoelectric efficiency of a material is to reduce the lattice thermal conductivity (k p ) while not affecting the other properties. In order to reduce the k p of the material, this paper introduces silicon (Si) nanoparticles (NPs) in Mg2Si to manipulate phonon scattering and mean free path. A series of simulations is performed with the metal silicide thermoelectric material MgxSix. The objective of this work is two-fold: 1) to determine the optimal Si nanoparticle (NP) concentration and 2) to determine the optimal MgxSix stoichiometry for minimizing the k p of the system. It should be noted, however, that the assumed reduction in thermal conductivity is only a result of reduced phonon transport and that minimal impact is made on the transport of electrons. Interestingly, the uniform off-stoichiometry (49.55 atomic percent (a/o) Si) sample of MgxSix resulted in a reduction of k p of 84.62 %, while the Si NP sample, with matching a/o Si, resulted in a reduction of k p of 78.82 %.

scholarly journals Local ferroelectric polarization switching driven by nanoscale distortions in thermoelectric $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aastha Vasdev ◽  
Moinak Dutta ◽  
Shivam Mishra ◽  
Veerpal Kaur ◽  
Harleen Kaur ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Lattice Thermal Conductivity ◽  
Direct Evidence ◽  
Temperature Dependent ◽  
Force Microscopy ◽  
Ferroelectric Domains ◽  
Pdf Analysis ◽  
Ferroelectric Transition Temperature

AbstractA remarkable decrease in the lattice thermal conductivity and enhancement of thermoelectric figure of merit were recently observed in rock-salt cubic SnTe, when doped with germanium (Ge). Primarily, based on theoretical analysis, the decrease in lattice thermal conductivity was attributed to local ferroelectric fluctuations induced softening of the optical phonons which may strongly scatter the heat carrying acoustic phonons. Although the previous structural analysis indicated that the local ferroelectric transition temperature would be near room temperature in $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te , a direct evidence of local ferroelectricity remained elusive. Here we report a direct evidence of local nanoscale ferroelectric domains and their switching in $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te using piezoeresponse force microscopy(PFM) and switching spectroscopy over a range of temperatures near the room temperature. From temperature dependent (250–300 K) synchrotron X-ray pair distribution function (PDF) analysis, we show the presence of local off-centering distortion of Ge along the rhombohedral direction in global cubic $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te . The length scale of the $${\text {Ge}}^{2+}$$ Ge 2 + off-centering is 0.25–0.10 Å near the room temperatures (250–300 K). This local emphatic behaviour of cation is the cause for the observed local ferroelectric instability, thereby low lattice thermal conductivity in $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te .

Ultra-low lattice thermal conductivity and high thermoelectric efficiency of K3AuO

2021 ◽  
Vol 130 (4) ◽  
pp. 045101
Author(s):  
Qi Zhong ◽  
Zhenhong Dai ◽  
Junping Wang ◽  
Yinchang Zhao ◽  
Sheng Meng
Keyword(s):  
Thermal Conductivity ◽  
Lattice Thermal Conductivity ◽  
Thermoelectric Efficiency

scholarly journals Diameter and Length Effect on Diffusive-Ballistic Phonon Transport in a Carbon Nanotube

2007 ◽  
Author(s):  
Junichiro Shiomi ◽  
Shigeo Maruyama
Keyword(s):  
Thermal Conductivity ◽  
Room Temperature ◽  
Single Walled Carbon Nanotubes ◽  
Phonon Transport ◽  
Boundary Resistance ◽  
Gradual Transition ◽  
Length Effect ◽  
Control Techniques ◽  
Non Equilibrium Molecular Dynamics ◽  
Walled Carbon Nanotubes

We report a non-equilibrium molecular dynamics (MD) study on heat conduction of finite-length single-walled carbon nanotubes (SWNTs). The length and diameter dependences of the thermal conductivity are quantified for a range of nanotube-lengths up to a micrometer at room temperature using two different temperature control techniques. A thorough investigation was carried out on the influence of intrinsic thermal boundary resistance between the temperature-controlled layers and the rest of the SWNT. The trend of length effect indicates a gradual transition from nearly pure ballistic phonon transport to diffusive-ballistic phonon transport. The nearly pure ballistic phonon transport was also confirmed by the minor diameter-dependence of thermal conductivity for short SWNTs. For longer SWNTs with stronger diffusive effect, the thermal conductivity is larger for SWNTs with smaller diameters.

A High Thermoelectric Performance ZT in p-Type LaSe2 Crystal

2021 ◽  
Vol 871 ◽  
pp. 203-207
Author(s):  
Jian Liu
Keyword(s):  
Thermal Conductivity ◽  
Power Factor ◽  
High Power ◽  
Density Functional ◽  
Lattice Thermal Conductivity ◽  
Phonon Transport ◽  
Thermoelectric Performance ◽  
Boltzmann Transport ◽  
High Power Factor ◽  
P Type

In this work, we use first principles DFT calculations, anharmonic phonon scatter theory and Boltzmann transport method, to predict a comprehensive study on the thermoelectric properties as electronic and phonon transport of layered LaSe2 crystal. The flat-and-dispersive type band structure of LaSe2 crystal offers a high power factor. In the other hand, low lattice thermal conductivity is revealed in LaSe2 semiconductor, combined with its high power factor, the LaSe2 crystal is considered a promising thermoelectric material. It is demonstrated that p-type LaSe2 could be optimized to exhibit outstanding thermoelectric performance with a maximum ZT value of 1.41 at 1100K. Explored by density functional theory calculations, the high ZT value is due to its high Seebeck coefficient S, high electrical conductivity, and low lattice thermal conductivity .

Thermoelectric Properties of CoSb3-based Skutterudite Compounds

2010 ◽  
Vol 1267 ◽  
Author(s):  
Adul Harnwunggmoung ◽  
Ken Kurosaki ◽  
Hiroaki Muta ◽  
Shinsuke Yamanaka
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Lattice Thermal Conductivity ◽  
Filling Ratio ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Alloy Scattering ◽  
Skutterudite Compound

AbstractCoSb3 is known as a skutterudite compound that could exhibit high thermoelectric figure of merit. However, the thermal conductivity of CoSb3 is relatively high. In order to enhance the thermoelectric performance of this compound, we tried to reduce the thermal conductivity of CoSb3 by substitution of Rh for Co and by Tl-filling into the voids. The polycrystalline samples of (Co,Rh)Sb3 and Tl-filled CoSb3 were prepared and the thermoelectric properties such as the Seebeck coefficient, electrical resistivity, and thermal conductivity were measured in the temperature range from room temperature to 750 K. The Rh substitution for Co reduced the lattice thermal conductivity, due to the alloy scattering effect. The minimum value of the lattice thermal conductivity was 4 Wm-1K-1 at 750 K obtained for (Co0.7Rh0.3)Sb3. Also the lattice thermal conductivity rapidly decreased with increasing the Tl-filling ratio. T10.25Co4Sb12 exhibited the best ZT values; the maximum ZT was 0.9 obtained at 600 K.

scholarly journals Dimer rattling mode induced low thermal conductivity in an excellent acoustic conductor

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Ji Qi ◽  
Baojuan Dong ◽  
Zhe Zhang ◽  
Zhao Zhang ◽  
Yanna Chen ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Single Crystals ◽  
Layered Structure ◽  
First Principles ◽  
Sound Speed ◽  
Lattice Dynamics ◽  
Room Temperature ◽  
Lattice Thermal Conductivity ◽  
Atomic Structures ◽  
Order Of Magnitude

Abstract A solid with larger sound speeds usually exhibits higher lattice thermal conductivity. Here, we report an exception that CuP2 has a quite large mean sound speed of 4155 m s−1, comparable to GaAs, but single crystals show very low lattice thermal conductivity of about 4 W m−1 K−1 at room temperature, one order of magnitude smaller than GaAs. To understand such a puzzling thermal transport behavior, we have thoroughly investigated the atomic structures and lattice dynamics by combining neutron scattering techniques with first-principles simulations. This compound crystallizes in a layered structure where Cu atoms forming dimers are sandwiched in between P atomic networks. In this work, we reveal that Cu atomic dimers vibrate as a rattling mode with frequency around 11 meV, which is manifested to be remarkably anharmonic and strongly scatters acoustic phonons to achieve the low lattice thermal conductivity.

Sign in / Sign up

Export Citation Format

Share Document