Solid Oxide Cells (SOC) devices are featured by reversibility since they can work in both SOFC (F=Fuel) and SOEC (E=Electrolysis) mode. Current electrolyte materials suffer of particles agglomeration and C poisoning reducing lifetime and performance. Very recently, advanced electrocatalysts, were metal nanoparticles are produced by exsolution, are overcoming these drawbacks. Much experimental work is mandatory to characterize the materials and device under SOFC and SOC conditions Hereby we propose to investigate the structural evolutions of a electrolytic cell working in both SOFC and SOEC conditions though in-situ experiments. Modifications will be detected by XRD measurements as function of the temperature, external atmosphere, time and cyclability. The approach involves the comparison with the separate materials (electrode and electrolyte, pellets) subjected to the same treatment to point out the difference and interaction between electrode and electrolyte materials.