Fabrication and performance of LaGaO3-based tubular SOFC's

Yttria stabilized zirconia (YSZ) is the most commonly used electrolyte material in solid oxide fuel cells (SOFC's). However, doped lanthanum gallate is an interesting alternative for use at intermediate temperatures (typically 600 - 750 degreesC). Commercially available La0.8Sr0.2Ga0.8Mg0.2O2.8 (LSGM) powder was mixed with a polymer-based binder system and extruded into two different size tubes. After sintering, the electrolyte tubes were approximately (a) 6 mm outside diameter, 0.55 mm wall thickness and 100-200 mm long and (b) 4 mm. outside diameter, 0.22 mm wall thickness and 50-100 mm long. The tubes were then fabricated into SOFC's, using a range of anode and cathode morphologies. The electrical performance of the cells was then tested using hydrogen as a fuel. A repeatable and constant power of over 2.5 W per cell was obtained at 800 degreesC and 0.7 V. The maximum power density of the tubular fuel cell with La0.6Sr0.4CoO3 cathode, Ce0.8Sm0.2O1.9 interlayer and a Ni anode was 482 mW/cm(2). This paper will present the fabrication procedure and parameters, fuel cell performance test results, and the effect of electrode morphologies on the performance of the fuel cells.