scholarly journals Enhanced thermoelectric performance of heavy-fermion compounds YbTM2Zn20 (TM = Co, Rh, Ir) at low temperatures

2019 ◽  
Vol 5 (5) ◽  
pp. eaaw6183
Author(s):  
Kaya Wei ◽  
Jennifer N. Neu ◽  
You Lai ◽  
Kuan-Wen Chen ◽  
Dean Hobbis ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Heavy Fermion ◽  
Energy Conversion Efficiency ◽  
Direct Conversion ◽  
Structural Features ◽  
Green Energy ◽  
Thermoelectric Performance ◽  
Phonon Modes ◽  
Large Power ◽  
Energy Technologies

Abstract:Thermoelectricity allows direct conversion between heat and electricity, providing alternatives for green energy technologies. Despite these advantages, for most materials the energy conversion efficiency is limited by the tendency for the electrical and thermal conductivity to be proportional to each other and the Seebeck coefficient to be small. Here we report counter examples, where the heavy fermion compounds YbTM2Zn20 (TM = Co, Rh, Ir) exhibit enhanced thermoelectric performance including a large power factor (PF = 74 μW/cm-K2; TM = Ir) and a high figure of merit (ZT = 0.07; TM = Ir) at 35 K. The combination of the strongly hybridized electronic state originating from the Yb f-electrons and the novel structural features (large unit cell and possible soft phonon modes) leads to high power factors and small thermal conductivity values. This demonstrates that with further optimization these systems could provide a platform for the next generation of low temperature thermoelectric materials.

scholarly journals Macroscopic weavable fibers of carbon nanotubes with giant thermoelectric power factor

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Natsumi Komatsu ◽  
Yota Ichinose ◽  
Oliver S. Dewey ◽  
Lauren W. Taylor ◽  
Mitchell A. Trafford ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Thermoelectric Power ◽  
Power Factor ◽  
Fermi Energy ◽  
Performance Enhancement ◽  
Thermoelectric Performance ◽  
Thermoelectric Power Factor ◽  
Large Power ◽  
Energy Tuning

AbstractLow-dimensional materials have recently attracted much interest as thermoelectric materials because of their charge carrier confinement leading to thermoelectric performance enhancement. Carbon nanotubes are promising candidates because of their one-dimensionality in addition to their unique advantages such as flexibility and light weight. However, preserving the large power factor of individual carbon nanotubes in macroscopic assemblies has been challenging, primarily due to poor sample morphology and a lack of proper Fermi energy tuning. Here, we report an ultrahigh value of power factor (14 ± 5 mW m−1 K−2) for macroscopic weavable fibers of aligned carbon nanotubes with ultrahigh electrical and thermal conductivity. The observed giant power factor originates from the ultrahigh electrical conductivity achieved through excellent sample morphology, combined with an enhanced Seebeck coefficient through Fermi energy tuning. We fabricate a textile thermoelectric generator based on these carbon nanotube fibers, which demonstrates high thermoelectric performance, weavability, and scalability. The giant power factor we observe make these fibers strong candidates for the emerging field of thermoelectric active cooling, which requires a large thermoelectric power factor and a large thermal conductivity at the same time.

scholarly journals Centimeter-Long Weavable Fibers of Carbon Nanotubes with Giant Thermoelectric Power Factor

2021 ◽  
Author(s):  
Natsumi Komatsu ◽  
Yota Ichinose ◽  
Oliver Dewey ◽  
Lauren Taylor ◽  
Mitchell Trafford ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Thermoelectric Power ◽  
Power Factor ◽  
Fermi Energy ◽  
Performance Enhancement ◽  
Thermoelectric Performance ◽  
Thermoelectric Power Factor ◽  
Electronic Density ◽  
Large Power

Abstract Low-dimensional materials have recently attracted much interest as thermoelectric materials because of their charge carrier confinement leading to thermoelectric performance enhancement. Carbon nanotubes are promising candidates because of their one-dimensionality in addition to their unique advantages such as flexibility and light weight. However, preserving the large power factor of individual carbon nanotubes in macroscopic assemblies has been challenging, primarily due to poor sample morphology and a lack of proper Fermi energy tuning. Here, we report an unprecedentedly high value of power factor (14±5 mWm-1K-2) for centimeter-long weavable fibers of aligned carbon nanotubes with ultrahigh electrical and thermal conductivity. Our theoretical simulations show that the observed giant power factor originates from the one-dimensional quantum confinement of charge carriers, appearing when the Fermi energy is near a van Hove singularity in the electronic density of states. We fabricated a textile thermoelectric generator based on these carbon nanotube fibers, which demonstrated high thermoelectric performance, weavablity, and scalability. The giant power factor we observed make these fibers strong candidates for the emerging field of thermoelectric active cooling, which requires a large thermoelectric power factor and a large thermal conductivity at the same time.

scholarly journals Strategy of extra Zr doping on the enhancement of thermoelectric performance for TiZrxNiSn synthesized by a modified solid-state reaction

2021 ◽  
Author(s):  
Jun-Liang Chen ◽  
Hengquan Yang ◽  
Chengyan Liu ◽  
Jisheng Liang ◽  
Lei Miao ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Solid State ◽  
Power Factor ◽  
Solid State Reaction ◽  
Lattice Thermal Conductivity ◽  
Phonon Scattering ◽  
Heusler Alloys ◽  
Thermoelectric Performance ◽  
Good Mechanical Property ◽  
Large Power

Abstract Half-Heusler alloys, which possess the advantages of high thermal stability, large power factor and good mechanical property, have been attracted increasing interest in mid-temperature thermoelectric application. In this work, the extra Zr-doped TiZrxNiSn samples were successfully prepared by a modified solid-state reaction followed by spark plasma sintering. It demonstrates that extra Zr doping could not only improve the power factor on account of an increase in Seebeck coefficient but also suppress the lattice thermal conductivity originated from the strengthened phonon scattering by the superlattice nanodomains and the secondary nanoparticles. As a consequence, an increased power factor of 3.29 mW m− 1 K− 2 and a decreased lattice thermal conductivity of 1.74 W m− 1 K− 1 are achieved in TiZr0.015NiSn, leading to a peak ZT as high as 0.88 at 773 K and an average ZT value up to 0.62 in the temperature range of 373 − 773 K. This work gives a guidance for optimizing the thermoelectric performance of TiNiSn-based alloys by modulating the microstructures on the secondary nanophases and superlattice nanodomains.

Soft Phonon Modes Leading to Ultralow Thermal Conductivity and High Thermoelectric Performance in AgCuTe

2018 ◽  
Vol 130 (15) ◽  
pp. 4107-4111 ◽  
Author(s):  
Subhajit Roychowdhury ◽  
Manoj K. Jana ◽  
Jaysree Pan ◽  
Satya N. Guin ◽  
Dirtha Sanyal ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Performance ◽  
Phonon Modes

Soft Phonon Modes Leading to Ultralow Thermal Conductivity and High Thermoelectric Performance in AgCuTe

2018 ◽  
Vol 57 (15) ◽  
pp. 4043-4047 ◽  
Author(s):  
Subhajit Roychowdhury ◽  
Manoj K. Jana ◽  
Jaysree Pan ◽  
Satya N. Guin ◽  
Dirtha Sanyal ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Performance ◽  
Phonon Modes

Soft phonon modes from off-center Ge atoms lead to ultralow thermal conductivity and superior thermoelectric performance in n-type PbSe–GeSe

2018 ◽  
Vol 11 (11) ◽  
pp. 3220-3230 ◽  
Author(s):  
Zhong-Zhen Luo ◽  
Shiqiang Hao ◽  
Xiaomi Zhang ◽  
Xia Hua ◽  
Songting Cai ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Lattice Thermal Conductivity ◽  
Thermoelectric Performance ◽  
Phonon Modes

The off-centered Ge leads to the ultralow lattice thermal conductivity and record high average ZT for n-type PbSe.

Structural features and thermoelectric performance of chalcopyrite Cu(In, Ga)Te2 system by isoelectronic substitution

2021 ◽  
Vol 26 ◽  
pp. 24-34
Author(s):  
Shuping Deng ◽  
Xianyan Jiang ◽  
Ziye Zhang ◽  
Junjie Liu ◽  
Lili Chen ◽  
...  
Keyword(s):  
Structural Features ◽  
Thermoelectric Performance

Axial guided wave characteristics in functionally graded one-dimensional hexagonal piezoelectric quasi-crystal cylinders

2021 ◽  
pp. 108128652110134
Author(s):  
B. Zhang ◽  
X.H. Wang ◽  
L. Elmaimouni ◽  
J.G. Yu ◽  
X.M. Zhang
Keyword(s):  
Coupling Effect ◽  
Energy Conversion Efficiency ◽  
Guided Wave ◽  
Functionally Graded ◽  
Phonon Modes ◽  
One Dimensional ◽  
Longitudinal Modes ◽  
Wave Characteristics ◽  
Piezoelectric Effects ◽  
Hollow Cylinders

In one-dimensional hexagonal piezoelectric quasi-crystals, there exist the phonon–phason, electro–phonon, and electro–phason couplings. Therefore, the phonon–phason coupling and piezoelectric effects on axial guided wave characteristics in one-dimensional hexagonal functionally graded piezoelectric quasi-crystal (FGPQC) cylinders are investigated by utilizing the Legendre polynomial series method. The dispersion curves and cut-off frequencies are illustrated. Wave characteristics in three hollow cylinders with different quasi-periodic directions are comparatively studied. Some new wave phenomena are revealed: the phonon–phason coupling and piezoelectric effects on the longitudinal and torsional phonon modes ( N = 0) vary as the quasi-periodic direction changes; the phonon–phason coupling effect on flexural–torsional modes in the r-, z-FGPQC hollow cylinders, and on flexural–longitudinal modes in ϑ-FGPQC hollow cylinders increases as N increases. The corresponding results obtained in this work lay the theoretical foundation for the design and manufacture of piezoelectric transducers with high resolution and energy-conversion efficiency.

Enhanced thermoelectric performance of band structure engineered GeSe1−xTex alloys

2021 ◽  
Vol 5 (6) ◽  
pp. 1734-1746
Author(s):  
D. Sidharth ◽  
A. S. Alagar Nedunchezhian ◽  
R. Akilan ◽  
Anup Srivastava ◽  
Bhuvanesh Srinivasan ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Band Structure ◽  
Power Factor ◽  
Thermoelectric Performance

The power factor of GeSe enhanced and thermal conductivity decreased by Te substitution and thereby, GeSe0.80Te0.20 exhibits high ZT.

Sign in / Sign up

Export Citation Format

Share Document