Comparison of the high temperature thermoelectric properties for Ag-doped and Ag-added Ca3Co4O9

Wang, Yan; Sui, Yu; Cheng, Jinguang; Wang, Xianjie; Su, Wenhui

doi:10.1016/j.jallcom.2008.10.162

Cited by 154 publications

(89 citation statements)

References 25 publications

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“…20 The ZT depends on the Seebeck effect, electrical conductivity, absolute temperature and thermal conductivity and is explained more in detail in chapter 7. There is therefore a need to develop n-type thermoelectric oxides that has similar ZT as the p-type oxides.…”

Section: History Of Oxides For Thermoelectricsmentioning

confidence: 99%

Growth and thermoelectric properties of CaMnO3-based thin films

Ekström¹

2018

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The field of thermoelectrics started in early 19 th century. Since the discovery of the Seebeck effect and the Peltier effect, thermoelectric modules have found their way into, mostly, niche applications such as radioisotope thermoelectric generators on space missions. Thermoelectric modules can also be used for cooling, utilizing the Peltier effect.Thermoelectrics are promising materials due to the operation nature of the modules. That is, they have no moving parts, no exhaust, long lifetime without maintenance, features that make them attractive for many applications. Despite these promising properties, thermoelectric modules are mostly used in niche applications. The main reason for this is conventional modules with the highest efficiency are commonly made of expensive and/or rare elements which prevents mass production.To tackle this problem, new materials are investigated to find a module that can be made widely available. Oxides are one possibility, where an added benefit is that they are chemically stable even at elevated temperature. The perovskite CaMnO3 is one of the more promising oxides, with elements that are abundant on earth and cheap. The material does suffer from low electrical conductivity which results in a low electrical conductivity and efficiency. A substantial effort has been put in to increase the efficiency of CaMnO3, but it still needs improvement.In my thesis, I have investigated the CaMnO3 system. CaMnO3 was synthesized using co-reactive RF-magnetron sputtering and post annealing. The synthesis method is already known but has not been used for deposition of perovskites. I have also demonstrated that this synthesis method can be used to dope CaMnO3 with niobium at appropriate levels for enhancing the efficiency. During the course of research underlying this thesis, I was enrolled in Agora Materiae, a multidisciplinary doctoral program at Linköping University, Sweden. VI VII Populärvetenskaplig SammanfattningMed dagens utveckling av teknologi ökar behovet av elektricitet. Många teknologier är små saker som behöver egna energikällor t.ex. sensorer. Dessa kan sitta på människokroppen, i datorer, i olika industrier och andra miljöer. Det de har gemensamt är att alla behöver en tillförlitlig kraftkälla som i många fall behöver fungera utan något underhåll samt ta lite plats.Ett annat problem i samhället är det stora slöseriet med energi i form av spillvärme, det vill säga en oönskad restprodukt, från i stort sett alla processer. Denna värme är i många fall helt outnyttjad och om man kunde ta till vara på denna värme skulle effektiviteten av många processer kunna ökas.Jag har undersökt material som skulle kunna lösa dessa problem, nämligen termoelektriska material. Sådana material har förmågan att omvandla värme till elektricitet och det som driver denna förmåga är Seebeck-effekten, uppkallad efter Thomas Seebeck som upptäckte den i början av 1820-talet. De fungerar genom att materialet har en varm och en kall sida. På den varma sidan rör sig elektronerna snabbare än på den kalla sid...

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Section: History Of Oxides For Thermoelectricsmentioning

confidence: 99%

Growth and thermoelectric properties of CaMnO3-based thin films

Ekström¹

2018

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“…1. [11][12][13][14][15][16][17][18][19][20][21][22] Some oxides indeed show reasonably large values of zT at high temperatures, and at least we can say that oxides are not out of the question. In this article, we will briefly review the unique features of oxide thermoelectrics by mainly focusing on α 2 σ at high temperatures.…”

Section: Introductionmentioning

confidence: 99%

Research Update: Oxide thermoelectrics: Beyond the conventional design rules

Terasaki

2016

APL Materials

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Materials' design for high-performance thermoelectric oxides is discussed. Since chemical stability at high temperature in air is a considerable advantage in oxides, we evaluate thermoelectric power factor in the high temperature limit. We show that highly disordered materials can be good thermoelectric materials at high temperatures, and the effects of strong correlation can further enhance the figure of merit by adding thermopower arising from the spin and orbital degrees of freedom. We also discuss the Kelvin formula as a promising expression for strongly correlated materials and show that the calculation based on the Kelvin formula can be directly compared with the cross-layer thermopower of layered materials. C 2016 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license

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“…This layer structure can exhibit rather low κ values because phonon scattering occurs efficiently at the interface between SrO layer and (SrTiO 3 ) n block layer. Very recently, a proper of Ag added in Ca 3 Co 4 O 9+δ ceramics resulted in an increase of the power factor, since Ag could improve electrical connections between cobaltite grains resulting in a significant increase in σ without largely increasing κ [13,14]. In addition, according to the reference [15], in the semiconducting matrix, metallic addition induces band bending which creates a potential barrier.…”

Section: Introductionmentioning

confidence: 99%

Improvement of the Thermoelectric Properties of (Sr0.9La0.1)3Ti2O7 by Ag Addition

et al. 2013

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Ruddlesden-Popper (RP) phase (Sr 0.9 La 0.1 ) 3 Ti 2 O 7 /xAg (x = 0, 0.05, 0.10, 0.15) are systematically investigated with regard to their phase composition and thermoelectric transport properties. The XRD results show that all oxide samples are of two phases and they have layered microstructure. The electrical conductivity is found to be increased simultaneously. And the absolute Seebeck coefficient decreases firstly and then increases Ag addition, which leads to (Sr 0.9 La 0.1 ) 3 Ti 2 O 7 /xAg (x = 0.10) sample possesses optimum power factor. The total thermal conductivity lowers with Ag addition. The dimensionless figure of merit, ZT, reaches 0.12 for x = 0.10. These results suggest that a proper of metal element Ag addition would be an effective way improving thermoelectric performance of (Sr 0.9 La 0.1 ) 3 Ti 2 O 7 system.

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Comparison of the high temperature thermoelectric properties for Ag-doped and Ag-added Ca3Co4O9

Cited by 154 publications

References 25 publications

Growth and thermoelectric properties of CaMnO3-based thin films

Growth and thermoelectric properties of CaMnO3-based thin films

Research Update: Oxide thermoelectrics: Beyond the conventional design rules

Improvement of the Thermoelectric Properties of (Sr0.9La0.1)3Ti2O7 by Ag Addition

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