Optimizing Growth Conditions for Cerium Oxide Thin Films As Model Electrodes for Solid Oxide Fuel Cells

Many recent studies have discussed the use of mixed ion and electron conductors  for electro-oxidation in solid oxide fuel cells (SOFCs). Cerium oxide, or ceria, is one such material that is an effective anode for SOFCs due to its ability to store and release oxygen with fast kinetics at intermediate temperatures (500 - 750˚C). Our aim was to optimize the growth of highly-ordered ceria thin films in order to correlate its electrochemical activity to the atomic arrangements on the surface using surface X-ray diffraction (SXRD). The films are grown by pulse laser deposition (PLD) on yttrium-stabilized zirconia (YSZ) single crystal substrates. Ideally, the ceria film should exhibit smooth surface morphology, high bulk crystallinity, and low surface impurity levels. Films were grown under a variety of conditions, from substrate cleaning methods to film annealing conditions. The results illustrate that the doping, PLD target processing parameters, and substrate crystal orientation have the greatest impact on the ceria film surface characteristics.