Degradation of La0.6Sr0.4CoO3-based cathode performance in solid oxide fuel cells due to the presence of aluminum oxide deposited through atomic layer deposition

Aluminum oxide was deposited into the porous cathode compartment of the (Sc,Al)-doped ZrO2 electrolyte cell through atomic layer deposition involving trimethyl aluminum and water as aluminum and oxygen sources, respectively. The deposited aluminum oxide had a detrimental effect on the cell performance of the zirconia-based SOFC unit cells in terms of the output power but did not change the open-cell voltage. Based on impedance spectroscopy, the open-cell voltage, and the output performance, the resultant degradation is attributed to the geometrical blockade of functional triple phase boundaries in La0.6Sr0.4CoO3 (LSCo)-based cathode materials of mixed ionic electronic conduction, indicating that there is a disruption at the interface between the charge collector and cathode that is proportional to the amount of deposited Al2O3.