Short stack and full system test using a ceramic A-site deficient strontium titanate anode

Abstract

A lanthanum and calcium co-doped A-site deficient strontium titanate (LSCTA–) was used as alternative anode material in Solid Oxide Fuel Cells (SOFC) with an active area of 100 cm2. Cell performance was tested in both short (5 cell) stack configuration, as well as a full HEXIS Galileo system (nominally 1 kW AC). Impregnation with various electrocatalysts, such as nickel and ceria, yielded promising fuel cell performance at this scale. The system test initially produced 70% of the nominal output power and is to the authors' knowledge the first all-oxide SOFC test on this scale. The strontium titanate backbone provides sufficient electronic conductivity to ensure acceptable ohmic losses. Power densities up to 200 mA cm−2 could be obtained at 900 °C, which compares well with Ni-cermet based anodes. Degradation is however severe at 900 °C, due to impregnate coarsening, but operation at 850 °C minimizes this effect. Short stacks could be stably operated for 1,600 hours with an output power of 100 mA cm−2. Stacks are redox stable, but currently not sulphur tolerant.