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 (LSCT A-) was used as alternative anode material in Solid Oxide Fuel Cells (SOFC) with an active area of 100 cm 2 . 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 1600 hours with an output power of 100 mA cm -2 . Stacks are redox stable, but currently not sulphur tolerant.

Evolution of the electrochemical interface in high-temperature fuel cells and electrolysers

“…Not only are competitive performances retained on scaling up (up to P = 0.7 W/cm 2 ), reasonable degradation rates are shown as well, i.e. 5 -6 %/kh, over 300 -1000 hours of testing 80,81 . The role of support-impregnate interaction on long term performance is illustrated by the fact that Nb doped SrTiO3 fuel-electrodes impregnated with Ru/CGO exhibit much improved stability (0.04 mV/h) over those impregnated with Ni/CGO (0.5 mV/h) under identical testing conditions 80 .…”

“…The various cells and systems presented comprise a range of cell geometries, including a self-supported YSZ scaffold impregnated with both fuel-electrode and oxygenelectrode components 78 . Particularly promising seems a number of studies assessing the use of A-site deficient SrTiO3 fuel-electrode backbones, impregnated with various catalysts [79][80][81] . Not only are competitive performances retained on scaling up (up to P = 0.7 W/cm 2 ), reasonable degradation rates are shown as well, i.e.…”

“…The role of support-impregnate interaction on long term performance is illustrated by the fact that Nb doped SrTiO3 fuel-electrodes impregnated with Ru/CGO exhibit much improved stability (0.04 mV/h) over those impregnated with Ni/CGO (0.5 mV/h) under identical testing conditions 80 . Long term stability of impregnated electrodes was also shown to be largely affected by operating temperature 81 . A full system test of nominally 1 kW was operated under relevant conditions (reformed natural gas, 850°C), which to date is the largest scale test of this kind using alternative fuel-electrode materials and impregnated electrodes 81 .…”

“…Long term stability of impregnated electrodes was also shown to be largely affected by operating temperature 81 . A full system test of nominally 1 kW was operated under relevant conditions (reformed natural gas, 850°C), which to date is the largest scale test of this kind using alternative fuel-electrode materials and impregnated electrodes 81 . …”

Screen Printed Porous La0.20Sr0.25Ca0.45TiO3 Fuel Electrode Scaffold Microstructures: Optimisation of Interaction with Impregnated Catalysts for More Durable Performance

“…The result of full-scale testing in the Hexis Galileo 1000N 1 kW (nominal) micro combined heat and power unit was degradation of power output from ~700 W to ~250 W after only 600 hours of testing (7).…”