Fabrication and Properties of an Anode-Supported Tubular IT-SOFC Based on Lanthanum Gallate

In the search for new electrolyte materials, the perovskite-based systems (ABO3) have been considered as one alternative option, particularly doped-LaGaO3, due to its high oxygen ion conductivity; La0.8Sr0.2Ga0.85Mg0.15 (LSGM) has been reported as having a conductivity of 0.14 s/cm at 800°C. In this program, work, the recently discovered anode material, LSCM (La0.75Sr0.25Cr0.5Mn0.5O3) will be used as the anode support. We have demonstrated that the material is chemically stable in contact with LSGM at temperatures as high as 1600°C for extended periods of time (200 h). After powder milling and/or mixing, the first step in cell fabrication, for this particular design, is the production of an anode support tube. Production of a robust ceramic-tube extrudate is a function of powder composition and mixing, extrusion pressure and speed, die configuration, and drying and firing times and temperatures. The extrudates were dried using a uniquely designed sample tube holder. The dried tube was then fired in a tube furnace. LSGM was then deposited onto the LSCM tube using a vacuum deposition technique. The cathode material, based on lanthanum (cobaltite) ferrite, was then deposited using a standard dip/spray coating technique, and fired to produce a single cell. The single anode support cell tubes were fully characterized and optimized for microstructural and chemical stability. The cells were then tested for electrical performance, and this paper will describe the preliminary results obtained from the single cells.