Tape casting fabrication,co-sintering and optimisation of anode/electrolyte assemblies for SOFC based on BIT07-Ni/BIT07

BaIn_0.3Ti_0.7O_2.85 (BIT07) is an electrolyte material for SOFC due to its high ionic conductivity level and its compatibility with mixed ionic and electronic conductor (MIEC) cathode materials, such as LSCF and Nd₂NiO_4+δ. BIT07 is also compatible with NiO to form a cermet as anode material. In this study, the electrolyte material has been prepared by tape casting and characterised. The coupled influences of the powder grain size and the firing temperature have been investigated and optimised to yield a dense electrolyte at 1300 °C. Then anode-supported half-cells (electrolyte/anode), based on BIT07/BIT07-Ni have been prepared by tape casting and co-sintered. The composition and the microstructure of the cermet anode (BIT07 grain size, amount and nature of pore-forming agent) have been optimised to achieve an area surface resistance (ASR) value of about 0.15 Ω cm² at 700 °C under wet reducing atmosphere. The stability of the most performing anode has been followed during 500 h and the observed degradation seems to be due a loss of nickel percolation.