1 A stability study of impregnated LSCF-GDC composite cathodes of solid oxide fuel cells Yihui Liu ab , Fangzhong Wang a , Bo Chi a , Jian Pu a , Li Jian a , San Ping Jiang b a Center for Fuel Cell Innovation, School of Materials Science and Engineering, State Key Laboratory of Material Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074, PR China b Fuels and Energy Technology Institute & Department of Chemical Engineering, Curtin University, Perth, WA 6102, Australia Abstract The performance degradation of composite cathodes of La0.6Sr0.4Co0.2Fe0.8O3-δ and Gd-doped ceria (LSCF-GDC), prepared by impregnating the porous GDC scaffold with a nitrate solution containing La, Sr, Co and Fe in desired composition, is investigated at 750 C and open circuit in air for 500 hrs. The performance of the impregnated LSCF-GDC composite cathodes deteriorates after testing at 750 o C for 500 hrs; the electrode polarization resistance (Rp) increases from 0.38 to 0.83 Ω cm 2 , and the electrode ohmic resistance (Ro) increases from 1.79 to 2.14 Ω cm 2 . The grain growth and coarsening of impregnated LSCF nanoparticles are responsible for the performance degradation of the cathodes. XPS analysis shows the enrichment of cobalt on the surface of the infiltrated LSCF-GDC cathodes and such surface segregation could also contribute to the degradation of the electrocatalytic activity of the cathodes. Introducing MgO and LaNi 0.6Fe0.4O3 phases can effectively suppress *Corresponding authors. Email: chibo@hust.edu.cn (B. Chi), s.jiang@curtin.edu.au (S.P. Jiang)