Effect of Processing Conditions on Curvature of Anode/Electrolyte SOFC Half-Cells Fabricated by Electrophoretic Deposition

Thin-electrolyte anode-supported solid oxide fuel cells (YSZ/NiO–YSZ) were fabricated for intermediate-temperature operation using electrophoretic deposition (EPD). During cosintering, the half-cells were observed to warp—an undesirable characteristic—due to mismatch in the sintering rates. The influence of the temperature for anode presintering—a key processing step—on the curvature of the half-cells induced by sintering was investigated over $700–1400°C$⁠. It was found that the maximum curvature occurred for an anode presintered at $900°C$⁠, while the minimum was observed at $1200°C$⁠. Anode presintering temperature was also found to affect the rate of electrophoretic deposition. At low presintering temperatures, the rate of EPD increased due to the enhancement in substrate (anode) electronic conductivity as a result of an increased percolating network of NiO. Further increases in presintering temperature, however, resulted in a decrease in the EPD rate due to the formation of a surface layer with poor electronic conductivity as a result of NiO diffusion from the NiO-YSZ anode to the sintering crucible.