Synthesis and characterization of gadolinium-doped ceria and barium cerate-based composite electrolyte material for IT-SOFC

A nanocomposite, containing gadolinium-doped ceria (GDC, Ce0.85Gd0.15O1.925) and 10 mol% gadolinium-doped barium cerate (BGC, BaCe0.85Gd0.15O2.925), was developed as an electrolyte material for intermediate temperature-solid oxide fuel cell. The composite powder was synthesized through an auto-combustion process that yielded the desired phases right after combustion. The powder was characterized using X-ray diffraction, particle size analysis, Brunauer–Emmett–Teller surface area analysis and transmission electron microscopy. The electrical properties of the composite electrolyte were characterized by electrochemical impedance spectroscopy under air as a function of temperature. The effect of second phase on total conductivity and activation energy of the composite material was compared with that of GDC of similar composition. For this, GDC (Ce0.85Gd0.15O1.925) powder was produced using a similar processing technique. The microstructural characterization of GDC and GDC–10BGC composite materials was studied through scanning electron microscopy. The electrochemical properties of planar cell, using GDC–10BGC as electrolyte and employing Ni–(GDC–10BGC) and La0.6Sr0.4Co0.2Fe0.8O3-δ-based anode and cathode materials, were investigated.