Co-free self-assembled nanocomposite films for solid oxide electrolysis cell anodes

Official URL: https://dx.doi.org/10.1149/1945-7111/ae8062

Solid oxide electrolysis cell anodes suffer from poor performance, especially upon long-term operation. The root cause of this is delamination of electrode from the electrolyte due to oxygen build up at the interface. To remedy these issues, nanocomposite (La, Sr)FeO3—(Ce, Sm)O2 electrodes with long triple phase boundaries fabricated by self-assembly from liquid precursors is proposed. Through nanostructuring and use of mixed ionic electronic conductor, facile oxygen evolution reaction that is distributed throughout the electrode thus high electrochemical performance and prevention of delamination while avoiding the use of Co are aimed. Correlation of X-ray diffraction, X-ray photoelectron spectroscopy, scanning transmission electron microscopy to the long-term EIS results conducted under anodic polarization revealed the parameters that played crucial roles in the electrochemical performances of liquid precursor derived electrodes. For example, pre-heat treated electrodes undergo amorphization, which is the main factor that diminishes the performance. In addition, introduction of a gadolinia doped ceria interlayer at the electrode/electrolyte interface influenced the surface cation distribution strongly and yielded a higher oxygen vacancy concentration, which acted to improve the electrochemical performance. This study provides crucial information that would enable SOECs with liquid precursor-derived nanocomposite air electrodes that perform well and do not delaminate upon long-term operation.