High-performance cement/SWCNT thermoelectric nanocomposites and a structural thermoelectric generator device towards large-scale thermal energy harvesting

Vareli, Ioanna; Tzounis, Lazaros; Tsirka, Kyriaki; Kavvadias, Ioannis E.; Tsongas, Konstantinos; Liebscher, Marco; Elenas, Anaxagoras; Gergidis, Leonidas N.; Barkoula, N.-M.; Paipetis, Alkiviadis S.

doi:10.1039/d1tc03495b

Cited by 25 publications

(21 citation statements)

References 54 publications

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“…The conductive paths are created by the conductive particles directly in contact with each other as cementitious crystals nucleate during the hydration process and repel SWCNT and nCB to the boundaries. Furthermore, since the distance between the adjacent nanoparticles is diminishing, junctions are formed, enabling electrons to easily pass through this junctions via “hopping” or “tunneling” mechanisms. , The electrical conductivity and the Seebeck coefficient of the organic TE materials are determined by the doping level. Increasing the doping level can lower S while increasing σ.…”

Section: Resultsmentioning

confidence: 99%

“…Ultrasonication was performed for 60 min at 25% (∼8 kJ) using a UP400S tip-ultrasonic probe processor (Hielscher Ultrasonics). The SWCNT content was selected based on our previous study , that demonstrated optimum TE performance for the prepared cementitious nanocomposites at 0.5 wt % SWCNT by weight of cement. For the preparation of the hybrid dispersions, nCB was added to the SWCNT solution at various contents (i.e., 0.25, 0.5, 1.0, and 2.0 wt % by weight of cement) under magnetic stirring.…”

Section: Methodsmentioning

confidence: 99%

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Structural Carbon-Enhanced Cementitious Thermoelectric Generators (TEGs): Optimal Energy Filtering and TEG Design for Outstanding Energy Harvesting

Vareli,

Gkaravela,

Polyviou

et al. 2023

ACS Appl. Electron. Mater.

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We report on the development of a cementitious structural thermoelectric generator (TEG), exhibiting a significantly improved power density of 1.2 W/m 2 , via the optimization of the thermoelectric response of individual thermoelements and the TEG assembly. Toward this aim, we combined nano carbon black (nCB) and single-walled carbon nanotubes (SWCNTs) within the cementitious matrix to maximize the carrier-filtering effect for optimal thermoelectric efficiency. The multidimensional carbon nanomaterials self-assembled through electrostatic forces during the dispersion process in aqueous media and formed conductive networks inside the cement matrix at low filler contents. Simultaneously, the additional interfaces between the nCB and the SWCNT nano-reinforcement supported the selective scattering of low-energy carriers. Thus, cementitious thermoelements with significantly enhanced Seebeck coefficient were produced. To our knowledge, the Seebeck, S (+4644.2 μV/K), and power factor, PF (1.51 × 10 4 μW/mK 2 ), values attained in this study are the highest ever reported to date for nanoadditivebased cementitious thermoelectric nanocomposites. The optimal design of the proposed Hybrid TEG device (utilizing thermoelements with only SWCNTs and with SWCNTs/nCB reinforcement) resulted in a decrease of the internal electrical resistance of our cementitious thermoelectric generator, further optimizing its power output, which enabled, under a small ΔΤ of 25 K, the generation of enough power for the autonomous operation of microelectronic devices, like wireless sensors.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Structural Carbon-Enhanced Cementitious Thermoelectric Generators (TEGs): Optimal Energy Filtering and TEG Design for Outstanding Energy Harvesting

Vareli,

Gkaravela,

Polyviou

et al. 2023

ACS Appl. Electron. Mater.

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“…Also, in some cases, during the addition of graphene nanoinclusions, graphite formations occur at grain boundaries via agglomeration during sintering . These secondary phases are detrimental concerning their thermoelectric performance; therefore, nanoinclusions should be chemically inert with the matrix phase. , Carbon allotropes are also famous for their use in cement and organic thermoelectric composites to improve electrical transport …”

Section: Classification Of Nanoinclusionsmentioning

confidence: 99%

“…52,85 Carbon allotropes are also famous for their use in cement and organic thermoelectric composites to improve electrical transport. 99 Fullerene was added to the thermoelectric matrixes such as skutterudite, half-Heusler, and Si−Ge compounds. Apart from reducing κ, fullerene maintains the σ with a lower reduction percentage because scattered electrons are compensated by fullerene carriers.…”

Section: ■ Classification Of Nanoinclusionsmentioning

confidence: 99%

Insights into the Classification of Nanoinclusions of Composites for Thermoelectric Applications

Theja

Karthikeyan

Assi

et al. 2022

ACS Appl. Electron. Mater.

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Thermoelectric composites are known for their enhanced power conversion performance via interfacial engineering and intensified mechanical, structural, and thermal properties. However, the selection of these nanoinclusions, for example, their type, size effect, volume fraction, distribution uniformity, coherency with host, carrier dynamics, and physical stability, plays a crucial role in modifying the host material thermoelectric properties. In this Review, we classify the nanoinclusions into five types: carbon allotropes, secondary thermoelectric phases, metallic materials, insulating oxides, and others. On the basis of the classification, we discuss the mechanisms involved in improving the ZT of nanocomposites involving reduction of thermal conductivity (κ) by phonon scattering, improving the Seebeck coefficient (α) via energy filtering effect and the electrical conductivity (σ) by carrier injection or carrier channeling. Comprehensibly, we validate that adding nanoinclusions with high electrical and low thermal conductivity as compared to the matrix material is the best way to optimize the interlocked thermoelectric parameters. Thus, collective doping and nanoinclusions in thermoelectric materials is the best possible solution to achieve a higher power conversion efficiency equivalent to other renewable energy technologies.

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“…Therefore, it is of significance to maximize the ZT value by enhancing the electrical transport properties (σ and α) and reducing thermal transport properties (κ). From the discovery of the Seebeck effect in carbon-fiber-reinforced concrete [ 14 ], numerous research studies have been carried out to explore various high ZT cement-based functional TE materials [ 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. Unfortunately, the performances of most kinds of TE cement are less than 1.0 × 10 −5 due to the poor electrical transport properties of the cement matrix.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Thermoelectric Performances of CNTs-Reinforced Cement Composites with Bi0.5Sb1.5Te3 for Pavement Energy Harvesting

et al. 2022

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Driven by the huge thermal energy in cement concrete pavements, thermoelectric (TE) cement has attracted considerable attention. However, the current TE cement shows poor performance, which greatly limits its application. Herein, a series of Bi0.5Sb1.5Te3/carbon nanotubes (CNTs) co-reinforced cement composites have been prepared, and their TE properties were systematically investigated. It was shown that the addition of Bi0.5Sb1.5Te3 particles can effectively improve the TE properties of CNTs-reinforced cement composites by building a better conductive network, increasing energy filtering and interfaces scattering. The Bi0.5Sb1.5Te3/CNTs cement composites with 0.6 vol.% of Bi0.5Sb1.5Te3 exhibits the highest ZT value of 1.2 × 10−2, increased by 842 times compared to that of the CNTs-reinforced cement composites without Bi0.5Sb1.5Te3. The power output of this sample with the size of 2.5 × 3.5 × 12 mm3 reaches 0.002 μW at a temperature difference of 19.1 K. These findings shed new light on the development of high-performance TE cement, which can guide continued advances in their potential application of harvesting thermal energy from pavements.

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High-performance cement/SWCNT thermoelectric nanocomposites and a structural thermoelectric generator device towards large-scale thermal energy harvesting

Abstract: For the first time, the thermoelectric properties of cement/ single-walled carbon nanotubes (SWCNT) nanocomposites over 3, 7, 14 and 28 days of hydration are reported, while a thermoelectric generator device...

Cited by 25 publications

References 54 publications

Structural Carbon-Enhanced Cementitious Thermoelectric Generators (TEGs): Optimal Energy Filtering and TEG Design for Outstanding Energy Harvesting

Structural Carbon-Enhanced Cementitious Thermoelectric Generators (TEGs): Optimal Energy Filtering and TEG Design for Outstanding Energy Harvesting

Insights into the Classification of Nanoinclusions of Composites for Thermoelectric Applications

Enhanced Thermoelectric Performances of CNTs-Reinforced Cement Composites with Bi0.5Sb1.5Te3 for Pavement Energy Harvesting

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