Impedance measurements performed on LSM/YSZ cathodes were carried out to investigate on the distribution of the active sites within the electrode. In order to evaluate the reliability/accuracy of the measured impedances in reflecting the true performance of an LSM/YSZ composite electrode, results extracted in different setup configurations were compared. To identify the steps inside the cathodic oxygen reduction the NLLS-Fit procedure is used. Furthermore, a simplified theoretical model of the electrode was developed. The model simulations agrees satisfactorily with the experimental data. The cells were produced by deposition of LSM/YSZ composite cathodes on one or both the sides of an electrolyte support, made by a tape casted YSZ (8 mol% Y2O3 + 92 mol% ZrO2) 187 μm thick (HTceramix). The cathodes and current collectors (1 cm2 of geometric area) were prepared and deposited on each side of the YSZ support by screen printing.. The characterization was performed by impedance measurements, and data were extracted between 923 and 1123K, at open circuit model (OCV) conditions and with different oxygen partial pressure. The electrochemical impedance analysis (EIS) was performed using an AUTOLAB pgstat 30 (Metrom) analyzer, over a frequency range of 0.1Hz to 1MHz with a 10 mV A.C. signal amplitude at equilibrium potential.
Modelling of the electrochemical data of composite SOFC cathode
CARPANESE, MARIA PAOLA;DELUCCHI, MARINA;CERISOLA, GIACOMO;BARBUCCI, ANTONIO
2008-01-01
Abstract
Impedance measurements performed on LSM/YSZ cathodes were carried out to investigate on the distribution of the active sites within the electrode. In order to evaluate the reliability/accuracy of the measured impedances in reflecting the true performance of an LSM/YSZ composite electrode, results extracted in different setup configurations were compared. To identify the steps inside the cathodic oxygen reduction the NLLS-Fit procedure is used. Furthermore, a simplified theoretical model of the electrode was developed. The model simulations agrees satisfactorily with the experimental data. The cells were produced by deposition of LSM/YSZ composite cathodes on one or both the sides of an electrolyte support, made by a tape casted YSZ (8 mol% Y2O3 + 92 mol% ZrO2) 187 μm thick (HTceramix). The cathodes and current collectors (1 cm2 of geometric area) were prepared and deposited on each side of the YSZ support by screen printing.. The characterization was performed by impedance measurements, and data were extracted between 923 and 1123K, at open circuit model (OCV) conditions and with different oxygen partial pressure. The electrochemical impedance analysis (EIS) was performed using an AUTOLAB pgstat 30 (Metrom) analyzer, over a frequency range of 0.1Hz to 1MHz with a 10 mV A.C. signal amplitude at equilibrium potential.
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