Effects of In-Air Post Deposition Annealing Process on the Oxygen Vacancy Content in Sputtered GDC Thin Films Probed via Operando XAS and Raman Spectroscopy.

We investigate the ionic mobility in room-temperature RF-sputtered gadolinium doped ceria (GDC) thin films grown on industrial solid oxide fuel cell substrates as a function of the air-annealing at 800 and 1000 °C. The combination of X-ray diffraction, X-ray photoelectron spectroscopy, operando X-ray absorption spectroscopy, and Raman spectroscopy allows us to study the different Ce/ Ce ratios induced by the post growth annealing procedure, together with the Ce valence changes induced by different gas atmosphere exposure. Our results give evidence of different kinetics as a function of the annealing temperature, with the sample annealed at 800 °C showing marked changes of the Ce oxidation state when exposed to both reducing and oxidizing gas atmospheres at moderate temperature (300 °C), while the Ce valence is weakly affected for the 1000 °C annealed sample.

State-of-the-Art Three-Dimensional Chemical Characterization of Solid Oxide Fuel Cell Using Focused Ion Beam Time-of-Flight Secondary Ion Mass Spectrometry Tomography.

In this paper the potential of time-of-flight secondary ion mass spectroscopy combined with focused ion beam technology to characterize the composition of a solid oxide fuel cell (SOFC) in three-dimension is demonstrated. The very high sensitivity of this method allows even very small amounts of elements/compounds to be detected and localized. Therefore, interlayer diffusion of elements between porous electrodes and presence of pollutants can be analyzed with a spatial resolution of the order of 100 nm.