SOLID OXIDE FUEL CELLS FABRICATION BY TAPE CASTING OF WATER BASED SUSPENSIONS

Solid Oxide Fuel Cells (SOFCs) are promising electrochemical devices which directly produce electrical energy by electrochemical combination of a fuel gas with an oxidant. The most attractive features of these converters are their high conversion efficiency and the possibility to process a wide variety of fuel gases due to the high operating temperatures.
SOFCs electrode materials were produced by tape casting starting from water-based suspensions in order to propose an easy, environmental friendly and health safe technology. Ceramic slurries were prepared using commercial oxide powders and casted by a laboratory scale tape caster. Green anode and electrolyte tapes were stacked together, warm-pressed and sintered at 1400°C to obtain planar half-cells in the anode supported configuration. By this method half cells with electrolyte thickness of the order of 5 µm are successfully prepared. In spite of the thermal expansion coefficient mismatch between anode and electrolyte materials, micro-structural analysis showed a perfect contact interface between co-sintered elements and delamination was not observed.
In order to improve the electrolyte/cathode interface, a YSZ porous layer was introduced in the green laminate and the sintered porous electrolyte was impregnated by a Pechini type gel precursor. Cells were then calcinated to allow perovskite formation. LSM20 current collector was then screen printed on the electrolyte/cathode interface. The electro-chemical performance of cells was studied by OCV measurements and polarization analysis in the temperature range between 750 and 900°C.