Alternative production route of tape cast supporting cathodes for SOFCs

Tape casting is a widely used shaping technique to produce large-area, flat ceramic layers for SOFC applications. This cheap and easily scalable ceramic process generally makes use of pore forming agents in the slurry to produce elements with the desired porosity. In this work, the possibility to obtain porous La0.8Sr0.2MnO3-Ce0.8Gd0.2O2 (LSM-GDC) supporting cathode without the use of pore formers was evaluated. The reactive sintering approach was therefore considered to exploit the porosity induced by the precursor decomposition during a single thermal treatment of calcining-debonding-sintering. A stable tape casting slurry of lanthanum, strontium and manganite precursor salts and GDC powder was therefore used in order to obtain large-area, crack free green tapes where La0.8Sr0.2MnO3 phase was formed directly during the sintering step. This process allowed to obtain 10 x10 cm2 LSM-GDC tapes, 800 ?m thick, with values of porosity and mechanical strength suitable for fuel cells applications without pore former addition and in a single thermal step. To the author knowledge this is the first time that a large area supporting cathode has been produced by tape casting using the reactive sintering approach