Tape casting of new electrolyte and anode materials for SOFCs operated at intermediate temperature

Abstract

An important task in SOFC research is the reduction of the operating temperature to 700 °C, to avoid premature ageing of the cell components and the use of expensive interconnect materials. This requires the development of new electrolytes and electrodes materials. Oxyapatite electrolytes have recently attracted considerable attention and we have already reported some interesting performances for the La 9Sr 1Si 6O 26.5 composition ( σ = 8.8 × 10 −3 S cm −1 at 700 °C) [Beaudet Savignat, S., Lima, A., Barthet, C. and Henry, A., In Proceedings of the International Symposium Solide Oxide Fuel Cells VIII, Vol. 2003–2007, pp. 372–378]. This study was centered on the manufacturing of an apatite electrolyte and a Ni/apatite cermet anode by the tape casting process, with a view to the development of anode/electrolyte 1/2 cells. Slurries compositions were first optimized to adjust green tapes characteristics. Secondly, we focused on the binder burnout and the sintering. Dense electrolytes were synthesized. The influence of the particle size of the apatite powder, with a fixed NiO powder particle size, and the influence of the addition of pyrolyzable organic particles on the sintering and the microstructure of the anode material were studied.