10 Years of materials research for solid oxide fuel cells at forschungszentrum julich

In 1995 a fuel cell program was established at Forschungszentrum Julich (FZJ) to combine various and independently existing activities on generic fuel cell research. As of this year, the materials development as well as the component manufacturing was focused on anode-supported cells. This contribution reviews the investigations on many materials and the fabrication processes applied for anode substrates, anodes, electrolytes and cathodes. Continuous effort on each of the components resulted in a steady progress in quality, size and performance of the solid oxide fuel cells (SOFCs). The electrochemical performance of anode-supported cells (ASC) with "conventional" electroceramic materials like lanthanum manganite as cathode, yttria-stabilized zirconia (YSZ) as electrolyte and a NiO/YSZ composite as anode and anode substrate was improved from about 0.15 W/cm(2) at 800 degrees C to 1.2 W/cm(2) by optimization of processing and microstructure. Considering new perovskite materials like lanthanum cobaltite/ferrite as cathode, a power density of 1.4-1.7 W/cm(2) has been obtained. In addition to these strongly focused activities on ASC, FZJ has carried out R + D projects together with industrial companies for the planar and tubular electrolyte-supported cell systems (Siemens, Dornier). This review, however, also discusses efforts that were less successful for anode-supported SOFCs. As examples are mentioned here the lanthanum gallates as electrolyte materials or low-cost NiO/Al2O3 substrates, which are not dimensionally stable in fuel gas atmosphere.