Increased proton transport property in Ba-doped LaScO3 thin film for metal support proton conducting oxide fuel cells

Metal-support solid oxide cells are attracting much interest as advanced fuel cells from high reliability and thermal management. There is limited number of metal support proton conducting fuel cells (MS-PCFCs) reported up to now, In this study, metal support BaZr 0.44 Ce 0.36 Y 0.2 O 3-δ (BZCY) electrolytes was studied and for solving the decreased open circuit voltage due to insufficient proton transport number, Ba-doped LaScO 3 (LBS) thin films on air side of BZCY cells were studied. Doped LaScO 3 -based oxides are known for their excellent chemical stability. In this study, Ba 2+ was substituted at the La 3+ site to induce further lattice expansion and oxygen vacancy formation, thereby promoting water incorporation and proton incorporation. The LBS layer, deposited by the pulsed laser deposition (PLD) technique at 800 °C to obtain a dense and thin proton-conducting layer including BZCY electrolyte. On the surface of the electrolyte of PCFCs, this LBS layer effectively enhances water uptake and proton conduction during cell operation. It was found that OCV of 1.08V close to the theoretical one and the highest power density of 903 and 453.6 mW/cm 2 at 700 and 600 °C, respectively, were achieved by depositing the La 0.85 Ba 0.15 ScO 3 (LBS15) layer with a thickness of 200 nm.