Benel, Cahit (2016)
Nanostructured Electrodes for Low Temperature Solid Oxide Fuel Cells.
Technische Universität Darmstadt
Dissertation, Erstveröffentlichung
Kurzbeschreibung (Abstract)
The reduction of the operating temperatures of solid oxide fuel cells (SOFCs) below 600 °C is one of the primary objectives to make them cost competitive with existing energy conversion technologies. However, the low ionic conductivity of the electrolytes and the sluggish electrochemical reaction rates at the electrodes are the major issues, which limit the performance of SOFCs at reduced operating temperatures. While the effect of limited ionic conductivity of the electrolytes at lower operating temperatures has been compensated by decreasing the electrolyte thicknesses, the utilization of nanostructured electrodes with enhanced electrochemical activities has been one of the most common approaches to overcome the electrode limitations associated with the reduced operating temperatures. The aim of the thesis is to obtain high performance nanostructured electrodes for SOFCs in a cost-effective and easily scalable production method. The state-of-the-art electrode materials of La0.6Sr0.4CoO3-δ (LSC) and Ni-Ce0.8Gd0.2O2-δ (NiO-GDC20) with ultrafine microstructure and high phase purity are synthesized by salt-assisted spray pyrolysis method. Nanostructured electrode thin films fabricated by spin coating of the water-based dispersions of LSC and NiO-GDC20 nanoparticles exhibit a three-dimensional porous microstructure with a grain size of around 50 nm. The electrochemical performances of the resulting electrode layers with thicknesses below 1 µm are optimized in the symmetrical cell configuration for the purpose to integrate them into the micro-solid oxide fuel cell (micro-SOFC) devices, which typically employ costly physical vapor deposited Pt thin film electrodes. The proof of concept for the fabrication of porous micro-SOFC electrodes by spin coating of suspensions of electrode nanoparticles is reported for the first time, and the first set of electrochemical data (12 mW/cm2 at 500 °C) demonstrates the feasibility of the developed thin film electrode fabrication method. Furthermore, the synthesized electrode materials are examined in ceria-based anode supported SOFC design. The promising initial electrochemical results (318 mW/cm2 at 600 °C) set the ground for further optimization of the anode supported LSC|Ce0.9Gd0.1O2-δ (GDC10)|Ni-GDC20 cells.
| Typ des Eintrags: | Dissertation | ||||
|---|---|---|---|---|---|
| Erschienen: | 2016 | ||||
| Autor(en): | Benel, Cahit | ||||
| Art des Eintrags: | Erstveröffentlichung | ||||
| Titel: | Nanostructured Electrodes for Low Temperature Solid Oxide Fuel Cells | ||||
| Sprache: | Englisch | ||||
| Referenten: | Hahn, Prof. Dr. Horst ; Ensinger, Prof. Dr. Wolfgang | ||||
| Publikationsjahr: | Dezember 2016 | ||||
| Ort: | Darmstadt | ||||
| Datum der mündlichen Prüfung: | 7 Juli 2016 | ||||
| URL / URN: | http://tuprints.ulb.tu-darmstadt.de/5846 | ||||
| Kurzbeschreibung (Abstract): | The reduction of the operating temperatures of solid oxide fuel cells (SOFCs) below 600 °C is one of the primary objectives to make them cost competitive with existing energy conversion technologies. However, the low ionic conductivity of the electrolytes and the sluggish electrochemical reaction rates at the electrodes are the major issues, which limit the performance of SOFCs at reduced operating temperatures. While the effect of limited ionic conductivity of the electrolytes at lower operating temperatures has been compensated by decreasing the electrolyte thicknesses, the utilization of nanostructured electrodes with enhanced electrochemical activities has been one of the most common approaches to overcome the electrode limitations associated with the reduced operating temperatures. The aim of the thesis is to obtain high performance nanostructured electrodes for SOFCs in a cost-effective and easily scalable production method. The state-of-the-art electrode materials of La0.6Sr0.4CoO3-δ (LSC) and Ni-Ce0.8Gd0.2O2-δ (NiO-GDC20) with ultrafine microstructure and high phase purity are synthesized by salt-assisted spray pyrolysis method. Nanostructured electrode thin films fabricated by spin coating of the water-based dispersions of LSC and NiO-GDC20 nanoparticles exhibit a three-dimensional porous microstructure with a grain size of around 50 nm. The electrochemical performances of the resulting electrode layers with thicknesses below 1 µm are optimized in the symmetrical cell configuration for the purpose to integrate them into the micro-solid oxide fuel cell (micro-SOFC) devices, which typically employ costly physical vapor deposited Pt thin film electrodes. The proof of concept for the fabrication of porous micro-SOFC electrodes by spin coating of suspensions of electrode nanoparticles is reported for the first time, and the first set of electrochemical data (12 mW/cm2 at 500 °C) demonstrates the feasibility of the developed thin film electrode fabrication method. Furthermore, the synthesized electrode materials are examined in ceria-based anode supported SOFC design. The promising initial electrochemical results (318 mW/cm2 at 600 °C) set the ground for further optimization of the anode supported LSC|Ce0.9Gd0.1O2-δ (GDC10)|Ni-GDC20 cells. |
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| URN: | urn:nbn:de:tuda-tuprints-58465 | ||||
| Sachgruppe der Dewey Dezimalklassifikatin (DDC): | 500 Naturwissenschaften und Mathematik > 500 Naturwissenschaften 500 Naturwissenschaften und Mathematik > 530 Physik 500 Naturwissenschaften und Mathematik > 540 Chemie 600 Technik, Medizin, angewandte Wissenschaften > 620 Ingenieurwissenschaften und Maschinenbau |
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| Fachbereich(e)/-gebiet(e): | 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Gemeinschaftslabor Nanomaterialien 11 Fachbereich Material- und Geowissenschaften |
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| Hinterlegungsdatum: | 18 Dez 2016 20:55 | ||||
| Letzte Änderung: | 18 Dez 2016 20:55 | ||||
| PPN: | |||||
| Referenten: | Hahn, Prof. Dr. Horst ; Ensinger, Prof. Dr. Wolfgang | ||||
| Datum der mündlichen Prüfung / Verteidigung / mdl. Prüfung: | 7 Juli 2016 | ||||
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| Suche nach Titel in: | TUfind oder in Google | ||||
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