Anot destekli düzlemsel katı oksit yakıt hücrelerinin şerit döküm ve sinterleme tekniği ile üretimi ve performans değerlendirmesi

Interest in solid oxide fuel cells has increased due to their ability to combine flexible fuel gas composition with efficient energy production. The most important goals include the long-term durability and performance of the cells. This is determined by three loss mechanisms: ohmic, polarization and activation polarization losses. To date, further development of anode-supported cells has been hampered by an incomplete understanding of the origin of the individual loss processes and their contribution to the internal resistance of the cell. Therefore, the primary goal of this dissertation was the clear identification and simultaneous physical interpretation of all polarization processes occurring in an anode- supported cell. Vanadium and Gadolinium doped four cathode samples (La0.595V0.005Sr0.4CoO3-∂ (LV05SC), La0.50Gd0.10Sr0.4CoO3-∂ (LG10SC), La0.57V0.03Sr0.4FeO3- ∂ (LV3SF), La0.595V0.005Sr0.4MnO3-∂ (LV05SM)) were synthesized using sol-gel method. Their crystal structure and elemental analysis were investigated by XRD and XPS techniques. The anode-supported cells were prepared using tape-casting method. Both YSZ (Yttria-stabilized Zirconia) and GDC (Gadolinium-doped Ceria) were used as electrolyte layers in different combinations. The surface and cross-section morphology of the sintered cells were studied with SEM analysis. For electrochemical characterization of the electrodes, Linear Sweep Voltammetry (LSV) and Electrochemical Impedance Spectroscopy (EIS) were performed. The analysis of the measured impedance required the use of four (RQ) circuits in series in the equivalent circuit model. All loss processes that contribute to the overall resistance of the individual cell were clearly identified. Up to six loss processes were identified by specifically analyzing the Distribution of Relaxation Time (DRT) while varying the operating conditions. Of the four cathodes, the LG10SC on GDC (35 μm)/YSZ showed the highest performance with 415 mW/cm2. The much higher electrode performance was clearly due to its much higher oxygen ion conductivity and high catalytic activity.