Electrical properties of thin bilayered YSZ/GDC SOFC electrolyte elaborated by sputtering

One of the present challenges for the commercialisation of planar solid oxide fuel cell is the reduction of its operating temperature, which requires the optimisation of the electrolyte nature and ionic conductivity. Thin layer technology seems suitable to decrease the electrolyte resistance at lower operating temperatures. Bilayered electrolytes are proposed and studied in terms of electrical performance. They are constituted of a gadolinia-doped ceria (GDC) layer (the most suitable candidates for IT solid oxide fuel cells (SOFC) in terms of ionic conductivity) protected by an ultra-thin YSZ layer (as electronic barrier). This work analyses the feasibility of bilayered GDC/YSZ electrolyte elaborated by DC magnetron spectroscopy. The bilayer was deposited on the state-of-the-art SOFC porous cathode, strontium-doped lanthanum manganite (LSM). The analysis of the electrical properties of such layers was performed by impedance spectroscopy. Experimental difficulties in order to obtain reliable results and interpretations are discussed.