Long term stability testing of oxide unicouple thermoelectric modules

Skomedal, Gunstein; Vehus, Tore; Kanas, Nikola; Singh, Sathya Prakash; Einarsrud, Mari‐Ann; Wiik, Kjell; Middleton, Hugh

doi:10.1016/j.matpr.2019.02.070

Cited by 8 publications

(13 citation statements)

References 15 publications

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“…Currently, the main strategies to improve the efficiency of oxide-based TE modules for waste heat harvesting are improving the doping of the individual p- and n-type materials to enhance their performance, reducing the contact resistance, , and including barrier layers to reduce diffusion . A notable improvement was achieved with “leg-segmented modules”; − however, oxide-based modules still suffer from poor durability caused by the instability of the metal-oxide interfaces at the hot side . Hence, there is a demand for new approaches and strategies to improve the performance of oxide-based modules in terms of long operation time under a high-temperature gradient.…”

Section: Introductionmentioning

confidence: 99%

“…10 A notable improvement was achieved with "leg-segmented modules"; 11−13 however, oxide-based modules still suffer from poor durability caused by the instability of the metal-oxide interfaces at the hot side. 14 Hence, there is a demand for new approaches and strategies to improve the performance of oxide-based modules in terms of long operation time under a high-temperature gradient.…”

Section: Introductionmentioning

confidence: 99%

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Time-Enhanced Performance of Oxide Thermoelectric Modules Based on a Hybrid p–n Junction

et al. 2020

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The present challenge with all-oxide thermoelectric modules is their poor durability at high temperatures caused by the instability of the metal-oxide interfaces at the hot side. This work explains a new module concept based on a hybrid p−n junction, fabricated in one step by spark plasma co-sintering of Ca 3 Co 4−x O 9+δ (CCO, p-type) and CaMnO 3−δ /CaMn 2 O 4 (CMO, n-type). Different module (unicouple) designs were studied to obtain a thorough understanding of the role of the in situ formed hybrid p−n junction of Ca 3 CoMnO 6 (CCMO, p-type) and Co-oxide rich phases (ptype) at the p−n junction (>700 °C) in the module performance. A time-enhanced performance of the modules attributed to this p−n junction formation was observed due to the unique electrical properties of the hybrid p−n junction being sufficiently conductive at high temperatures (>700 °C) and nonconductive at moderate and low temperatures. The alteration of module design resulted in a variation of the power density from 12.4 (3.1) to 28.9 mW/cm 2 (7.2 mW) at ΔT ∼ 650 °C after 2 days of isothermal hold (900 °C hot side). This new concept provides a facile method for the fabrication of easily processable, cheap, and high-performance hightemperature modules.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Time-Enhanced Performance of Oxide Thermoelectric Modules Based on a Hybrid p–n Junction

et al. 2020

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“…Skomedal et al [9] presented the relationship between the characteristics of each leg of the TEG and the final parameters of the module, such as the internal resistance, open-circuit voltage, and maximum generated power. It is known that the figure of merit ZT = S 2 σT/k is used to describe the performances of each TE material, depending on the properties: Seebeck coefficient (S), electrical conductivity (σ), thermal conductivity (k), and absolute temperature (T) [9].…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, oxide-based thermoelectric materials are capable of operating at high temperatures under air, maintaining their structural and electric stability. However, these materials have received much less attention than the current ones, due to their relatively low efficiency [9]. Another important issue deals with the difficulties in providing reliable electrical contacts between oxide based legs and interconnecting metal stripes.…”

Section: Introductionmentioning

confidence: 99%

“…Another important issue deals with the difficulties in providing reliable electrical contacts between oxide based legs and interconnecting metal stripes. For these reasons, some research groups are developing and improving thermoelectric materials and generators based on cheap and abundant oxide materials such as Bi 2 Ba 2 Co 2 O x [10], Bi 2 AE 2 Co 2 O x with AE = Ca, Sr, and Ba [11], Ca 2.7 Bi 0.3 Co 4 O 9 and CaMn 0.95 Ta 0.05 O 3 [12], CaMnO 3 -based materials [13] and CaMnO 3 and Ca 3 Co 4 O 9 [9]. Several examples of oxide-based thermoelectric modules can be found in the literature, such as: CaMnO 3 -Ca 3 Co 4 O 9 [9], Ca 2.7 Bi 0.3 Co 4 O 9 -CaMn 0.95 Ta 0.05 O 3 [12], Lidoped NiO -Ba 0.2 Sr 0.8 PbO 3 [14], Ca 2.75 Gd 0.25 Co 4 O 9 -Ca 0.92 La 0.08 MnO 3 [15], Ca 2.7 Bi 0.3 Co 4 O 9 -CaMn 0.98 Mo 0.02 O 3 [16], Ca 2.7 Bi 0.3 Co 4 O 9 -La 0.9 Bi 0.1 NiO 3 [17,18], Ca 3 Co 4 O 9 -(ZnO) 7 In 2 O 3 [19] and Bi 2 Te 3 -CMO [20].…”

Section: Introductionmentioning

confidence: 99%

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Thermoelectric modules built using ceramic legs grown by laser floating zone

Ferreira

Lopes

Costa

et al. 2020

Ceramics International

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Performance of a Thermoelectric Module Based on n-Type (La0.12Sr0.88)0.95TiO3−δ and p-Type Ca3Co4−xO9+δ

Kanas

Skomedal

Desissa

et al. 2020

Journal of Elec Materi

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Here, we present the performance of a thermoelectric (TE) module consisting of n-type (La 0.12 Sr 0.88 ) 0.95 TiO 3 and p-type Ca 3 Co 4Àx O 9+d materials. The main challenge in this investigation was operating the TE module in different atmospheric conditions, since n-type has optimum TE performance at reducing conditions, while p-type has optimum at oxidizing conditions. The TE module was exposed to two different atmospheres and demonstrated higher stability in N 2 atmosphere than in air. The maximum electrical power output decreased after 40 h when the hot side was exposed to N 2 at 600°C, while only 1 h at 400°C in ambient air was enough to oxidize (La 0.12 Sr 0.88 ) 0.95 TiO 3 followed by a reduced electrical power output. The module generated maximum electrical power of 0.9 mW ($ 4.7 mW/cm 2 ) at 600°C hot side and DT $ 570 K in N 2 , and 0.15 mW ($ 0.8 mW/cm 2 ) at 400°C hot side and DT $ 370 K in air. A stability limit of Ca 3 Co 3.93 O 9+d at $ 700°C in N 2 was determined by in situ high-temperature x-ray diffraction.

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Long term stability testing of oxide unicouple thermoelectric modules

Cited by 8 publications

References 15 publications

Time-Enhanced Performance of Oxide Thermoelectric Modules Based on a Hybrid p–n Junction

Time-Enhanced Performance of Oxide Thermoelectric Modules Based on a Hybrid p–n Junction

Thermoelectric modules built using ceramic legs grown by laser floating zone

Performance of a Thermoelectric Module Based on n-Type (La0.12Sr0.88)0.95TiO3−δ and p-Type Ca3Co4−xO9+δ

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