Bonding Heterogeneity in Mixed-Anion Compounds Realizes Ultralow Lattice Thermal Conductivity

<a>Crystalline materials with intrinsically low lattice thermal conductivity (</a>κlat) pave the way towards high performance in various energy applications, including thermoelectrics. Here we demonstrate a strategy to realize ultralow κlat using mixed-anion compounds. Our calculations reveal that locally distorted structures in chalcohalides MnPnS2Cl (Pn = Sb, Bi) derives a bonding heterogeneity, which in turn causes a peak splitting of the phonon density of states. This splitting induces a large amount of scattering phase space. Consequently, κlat of MnPnS2Cl is significantly lower than that of a single-anion sulfide CuTaS3 with a similar crystal structure. Experimental κlat of MnPnS2Cl takes an ultralow value of about 0.5 W m−1 K−1 at 300 K. Our findings will encourage the exploration of thermal transport in mixed-anion compounds, which remain a vast unexplored space, especially regarding unexpectedly low κlat in lightweight materials derived from the bonding heterogeneity.

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Lattice thermal conductivity of Si nanowires: Effect of modified phonon density of states

Journal of Applied Physics ◽

10.1063/1.2976314 ◽

2008 ◽

Vol 104 (5) ◽

pp. 054314 ◽

Cited By ~ 24

Author(s):

Xiang Lü

Keyword(s):

Thermal Conductivity ◽

Density Of States ◽

Lattice Thermal Conductivity ◽

Phonon Density ◽

Phonon Density Of States ◽

Si Nanowires

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Hierarchical Structuring to Break the Amorphous Limit of Lattice Thermal Conductivity in High-Performance SnTe-Based Thermoelectrics

ACS Applied Materials & Interfaces ◽

10.1021/acsami.0c09781 ◽

2020 ◽

Vol 12 (32) ◽

pp. 36370-36379

Author(s):

Lijun Wang ◽

Min Hong ◽

Qiang Sun ◽

Yuan Wang ◽

Luo Yue ◽

...

Keyword(s):

Thermal Conductivity ◽

High Performance ◽

Lattice Thermal Conductivity ◽

Hierarchical Structuring

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Thermal Conductivity of Zn4−xCdxSb3 Solid Solutions

MRS Proceedings ◽

10.1557/proc-478-103 ◽

1997 ◽

Vol 478 ◽

Cited By ~ 20

Author(s):

T. Caillat ◽

A. Borshchevsky ◽

J. -P. Fleurial

Keyword(s):

Thermal Conductivity ◽

High Performance ◽

Figure Of Merit ◽

Lattice Thermal Conductivity ◽

State Of The Art ◽

Thermoelectric Figure Of Merit ◽

Thermoelectric Figure ◽

Jet Propulsion ◽

P Type ◽

Electrical Conductors

Abstractβ-Zn4Sb3 was recently identified at the Jet Propulsion Laboratory as a new high performance p-type thermoelectric material with a maximum dimensionless thermoelectric figure of merit ZT of 1.4 at a temperature of 673K. A usual approach, used for many state-of-the-art thermoelectric materials, to further improve ZT values is to alloy β-Zn4Sb3 with isostructural compounds because of the expected decrease in lattice thermal conductivity. We have grown Zn4−xCdxSb3 crystals with 0.2≤x<1.2 and measured their thermal conductivity from 10 to 500K. The thermal conductivity values of Zn4−xCdxSb3 alloys are significantly lower than those measured for β-Zn4Sb3 and are comparable to its calculated minimum thermal conductivity. A strong atomic disorder is believed to be primarily at the origin of the very low thermal conductivity of these materials which are also fairly good electrical conductors and are therefore excellent candidates for thermoelectric applications.

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Thermal Rectification in Bi-Layered Nanofilm by Molecular Dynamics

ASME 2009 7th International Conference on Nanochannels, Microchannels and Minichannels ◽

10.1115/icnmm2009-82213 ◽

2009 ◽

Author(s):

Shuai-Chuang Wang ◽

Xin-Gang Liang

Keyword(s):

Thermal Conductivity ◽

Molecular Dynamics ◽

Heat Flux ◽

Density Of States ◽

Atomic Mass ◽

Interfacial Thermal Resistance ◽

Phonon Density ◽

Total Thickness ◽

Phonon Density Of States ◽

Thermal Rectification

A thermal rectifier has such nature that its thermal conductance or thermal conductivity has different values with reversed heat flux direction. This work investigates the rectification of the cross-plane thermal conductivity and interfacial thermal resistance of nanoscale bi-layered films using the nonequilibrium molecular dynamics (NEMD) method. The effects of the thickness of the single layer with the total thickness constant, the ratio of the atomic mass and temperature difference in the two ends on the thermal rectification are all considered. The results of the simulations show that the thermal conductivity and the interfacial thermal resistance are different for the heat flux with opposite directions. For the composite film with two layers of the same thicknesses, the thermal conductivity is larger when the heat flux direction is from the light layer to the heavy one. The difference becomes larger when the ratio of the atomic mass in the two layers increases. Increasing the heat flux makes the rectification of thermal conductivity larger, which means that the rectification is dependent on the temperature. For the composite film with fixed total thickness, the rectification becomes smaller when the thickness of the light layer increases. When the light layer is thick enough, the rectification is found reversed, which means that the thermal conductivity is larger with the heat flux direction from the heavy layer to the light one. The phonon density of states is also calculated to explain the phenomenon, and it is found that the overlap of the phonon density of states for the two layers is almost same even if the rectification of the thermal conductivity is reversed.

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Efficient interlayer charge release for high-performance layered thermoelectrics

National Science Review ◽

10.1093/nsr/nwaa085 ◽

2020 ◽

Cited By ~ 3

Author(s):

Hao Zhu ◽

Zhou Li ◽

Chenxi Zhao ◽

Xingxing Li ◽

Jinlong Yang ◽

...

Keyword(s):

Thermal Conductivity ◽

Electrical Conductivity ◽

Seebeck Coefficient ◽

Carrier Concentration ◽

High Performance ◽

Lattice Thermal Conductivity ◽

Transport Barrier ◽

High Seebeck Coefficient ◽

Valence Bands ◽

Increase Carrier Concentration

Abstract Many layered superlattice materials intrinsically possess large Seebeck coefficient and low lattice thermal conductivity, but poor electrical conductivity because of the interlayer transport barrier for charges, which has become a stumbling block for achieving high thermoelectric performance. Herein, taking BiCuSeO superlattice as an example, it is demonstrated that efficient interlayer charge release can increase carrier concentration, thereby activating multiple Fermi pockets through Bi/Cu dual vacancies and Pb codoping. Experimental results reveal that the extrinsic charges, which are introduced by Pb and initially trapped in the charge-reservoir [Bi2O2]2+ sublayers, are effectively released into [Cu2Se2]2− sublayers via the channels bridged by Bi/Cu dual vacancies. This efficient interlayer charge release endows dual-vacancy- and Pb-codoped BiCuSeO with increased carrier concentration and electrical conductivity. Moreover, with increasing carrier concentration, the Fermi level is pushed down, activating multiple converged valence bands, which helps to maintain a relatively high Seebeck coefficient and yield an enhanced power factor. As a result, a high ZT value of ∼1.4 is achieved at 823 K in codoped Bi0.90Pb0.06Cu0.96SeO, which is superior to that of pristine BiCuSeO and solely doped samples. The present findings provide prospective insights into the exploration of high-performance thermoelectric materials and the underlying transport physics.

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