Significantly enhanced chemical stability in interface-controlled Cu2+Se-reduced graphene oxide composites and related thermoelectric performances

Tak, Jang-Yeul; Jin, Seung Hyun; Nam, Woo Hyun; Cho, Jung Young; Seo, Won‐Seon; Lee, Gil-Geun; Cho, Hyung Koun; Lim, Young Soo

doi:10.1016/j.jeurceramsoc.2020.08.023

Cited by 15 publications

(3 citation statements)

References 34 publications

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“…The β-Cu 2 Se ( Fm 3̅ m ) has a cubic anti-fluorite structure and exhibits a superionic feature, in which Cu ions are randomly distributed and move freely within the face-centered cubic sublattice of Se. , The mobile Cu ions travel freely among interstitial sites just like a fluid, which not only causes strong phonon scattering to reduce the phonon mean free path distinctly but also eliminates some lattice vibration modes, leading to low specific heat. ,− In the past few years, a high ZT of about 1.5 at 1000 K has been reported in the bulk Cu 2 Se . Subsequently, various effective methods have been applied to improve the ZT of Cu 2 Se, such as doping elements, ,− alloying, ,, nanostructuring, and so on. Nunna et al.…”

Section: Introductionmentioning

confidence: 99%

“…17,24−27 In the past few years, a high ZT of about 1.5 at 1000 K has been reported in the bulk Cu 2 Se. 16 Subsequently, various effective methods have been applied to improve the ZT of Cu 2 Se, such as doping elements, 18,28−32 alloying, 12,13,33 nanostructuring, 34 and so on. Nunna et al reported an extremely high ZT of 2.4 at 1000 K by adding organic impurities, carbon nanotubes, into Cu 2 Se compounds.…”

Section: ■ Introductionmentioning

confidence: 99%

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Synergetic Optimization of Electrical and Thermal Transport Properties by Cu Vacancies and Nanopores in Cu₂Se

Zhao

Ning

et al. 2021

ACS Appl. Mater. Interfaces

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In this study, a series of Cu2+x–y In y Se (−0.3 ≤ x ≤ 0.2 and 0 ≤ y ≤ 0.05) samples were prepared by melting and the spark plasma sintering method. X-ray diffraction measurements indicate that the Cu-deficient samples (x = −0.3 y = 0 and x = −0.2 y = 0) prefer to form the cubic phase (β-Cu2Se). Adding excessive Cu or introducing In atoms into the Cu2Se matrix triggers a phase transition from the β to α phase. Positron lifetime measurements confirm the reduction in Cu vacancy concentration by adding excessive Cu or introducing In atoms into Cu2Se, which causes a dramatic decrease in carrier concentration from 1.59 × 1021 to 5.0 × 1019 cm–3 at room temperature. The samples with In contents of 0.01 and 0.03 show a high power factor of about 1 mW m–1 K–2 at room temperature due to the optimization of the carrier concentration. Meanwhile, the excess Cu content and doping of In atoms also favor the formation of nanopores. These pores have strong interaction with phonons, leading to remarkable reduction in lattice thermal conductivity. Finally, a high ZT value of about 1.44 is achieved at 873 K in the Cu1.99In0.01Se (x = 0 and y = 0.01) sample, which is about twice that of the Cu-deficient sample (Cu1.7Se). Our work provides a viable insight into tuning vacancy defects to improve efficiently the electrical and thermal transport performance for copper-based thermoelectric materials.

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Section: Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Synergetic Optimization of Electrical and Thermal Transport Properties by Cu Vacancies and Nanopores in Cu₂Se

Zhao

Ning

et al. 2021

ACS Appl. Mater. Interfaces

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“…Hu et al significantly improved the ZT value of the α-Cu 2 Se material by embedding organic compound carbon nanodots (CDs) into Cu 2 Se, which obviously reduced the thermal conductivity due to the energy filtering effect of the carbon nanodots in the matrix . In addition, it is reported that the addition of carbon inclusion in various polymorphs (such as graphite, carbon black, carbon fiber, carbon nanotubes, and other materials) in Cu 2 Se can also effectively improve the thermoelectric performance due to the acoustic mismatch between the carbon atom and the main compound, which forms a large grain boundary resistance due to the lightweightedness of the carbon atom. − …”

Section: Introductionmentioning

confidence: 99%

Extremely Low Lattice Thermal Conductivity and Significantly Enhanced Near-Room-Temperature Thermoelectric Performance in α-Cu₂Se through the Incorporation of Porous Carbon

Zhao,

Yu,

Zhou

et al. 2023

ACS Appl. Mater. Interfaces

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In this work, a series of Cu 2 Se/x wt % porous carbon (PC) (x = 0, 0.2, 0.4, 0.6, 0.8, 1) composite materials were synthesized by ball milling and spark plasma sintering (SPS). The highly ordered porous carbon was synthesized by a hydrothermal method using mesoporous silica (SBA-15) as the template. X-ray diffraction results show that the incorporation of porous carbon induces a phase transition of Cu 2 Se from the β phase to the α phase. Meanwhile, the addition of porous carbon reduces the carrier concentration from 2.7 × 10 21 to 2.45 × 10 20 cm −3 by 1 order of magnitude. The decrease of the carrier concentration leads to the reduction of electrical conductivity and the increase of the Seebeck coefficient, which results in the enhancement of the power factor. On the other hand, the incorporation of porous carbon into Cu 2 Se increases the porosity of the composites and also introduces more interfaces between the two materials, which is evidenced by positron annihilation lifetime measurements. Both pores and interfaces greatly enhance phonon scattering, leading to extremely low lattice thermal conductivity. In addition, the decrease of electrical conductivity also causes a sufficient reduction in electronic thermal conductivity. Due to the above synergistic effects, the thermoelectric performance of the Cu 2 Se/PC composite is significantly enhanced with a maximum ZT value of 0.92 at 403 K in the Cu 2 Se/1 wt % PC composite, which is close to that of the Bi 2 Te 3 -based materials. Our work shows that α-Cu 2 Se has great potential for near-roomtemperature thermoelectric materials.

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Interface‐Enhanced High‐Temperature Thermoelectricity in Cu_1.99Se/B₄C Composites with Synergistically Improved Mechanical Strength

Yu,

Hu,

Jiang

et al. 2024

Advanced Energy Materials

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Degenerate semiconductors usually demonstrate a metallic‐like conduction behavior, showing limited carrier mobility at high temperatures. Herein, by incorporating B4C nanoparticles into the Cu1.99Se system, an unusual switch from the “degenerate” to “non‐degenerate” semiconducting behavior is revealed as a result of the engineered interfaces. Heterogeneous interfaces and disordered Cu2Se amorphous phases are introduced in the Cu1.99Se/B4C composites, which generate a trapping effect against the mobile Cu ions, leading to a distinctive “hump” signature for electrical conductivity. Benefiting from this rare high‐temperature thermoelectric response, a high power factor is obtained due to reduced carrier concentration and enhanced mobility, and low lattice thermal conductivity is retained because of relatively stronger anharmonic lattice vibrations. Consequently, the Cu1.99Se + 0.9 vol.% B4C sample at least achieves a maximum thermoelectric figure of merit (ZT) of 2.6 at 1025 K with synergistically enhanced mechanical robustness. The present interface engineering strategy may be applicable to other thermoelectric materials with ionic migration characteristics.

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Significantly enhanced chemical stability in interface-controlled Cu2+Se-reduced graphene oxide composites and related thermoelectric performances

Cited by 15 publications

References 34 publications

Synergetic Optimization of Electrical and Thermal Transport Properties by Cu Vacancies and Nanopores in Cu₂Se

Synergetic Optimization of Electrical and Thermal Transport Properties by Cu Vacancies and Nanopores in Cu₂Se

Extremely Low Lattice Thermal Conductivity and Significantly Enhanced Near-Room-Temperature Thermoelectric Performance in α-Cu₂Se through the Incorporation of Porous Carbon

Interface‐Enhanced High‐Temperature Thermoelectricity in Cu_1.99Se/B₄C Composites with Synergistically Improved Mechanical Strength

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Significantly enhanced chemical stability in interface-controlled Cu2+Se-reduced graphene oxide composites and related thermoelectric performances

Cited by 15 publications

References 34 publications

Synergetic Optimization of Electrical and Thermal Transport Properties by Cu Vacancies and Nanopores in Cu2Se

Synergetic Optimization of Electrical and Thermal Transport Properties by Cu Vacancies and Nanopores in Cu2Se

Extremely Low Lattice Thermal Conductivity and Significantly Enhanced Near-Room-Temperature Thermoelectric Performance in α-Cu2Se through the Incorporation of Porous Carbon

Interface‐Enhanced High‐Temperature Thermoelectricity in Cu1.99Se/B4C Composites with Synergistically Improved Mechanical Strength

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Product

Resources

About

Synergetic Optimization of Electrical and Thermal Transport Properties by Cu Vacancies and Nanopores in Cu₂Se

Synergetic Optimization of Electrical and Thermal Transport Properties by Cu Vacancies and Nanopores in Cu₂Se

Extremely Low Lattice Thermal Conductivity and Significantly Enhanced Near-Room-Temperature Thermoelectric Performance in α-Cu₂Se through the Incorporation of Porous Carbon

Interface‐Enhanced High‐Temperature Thermoelectricity in Cu_1.99Se/B₄C Composites with Synergistically Improved Mechanical Strength