Fabrication of multi-layered structures for proton conducting ceramic cells

Protonic ceramic fuel cells offer a high potential to produce electrical energy in a very efficient way. The performance of such a device among others is highly dependent on the electrolyte material and its thickness. Therefore, multilayer structures are used to reduce the electrolyte thickness down to 10-20 μm, supported by a much thicker porous anode. In this work sequential tape-casting is used to fabricate half-cells consisting of a BZCY electrolyte and a BZCY/NiO support which also serves as the anode layer. The starting powders are characterised as well as the thermal behaviour of the half-cells during heat treatment. Sintering experiments show that a temperature of T ≥ 1450 °C is needed to achieve the desired microstructure. After that a scale-up approach to a size of the half-cells of about 25 cm 2 is shown. The influence of the processing temperature on the microstructure is shown by detailed XRD and SEM studies. The formation of a BaY 2 NiO 5 transient liquid phase during the heat treatment of the cells is clearly demonstrated. Finally, the proton conductivity of the tape-cast cells shows competitive values of σ = 0.003 S cm −1 at 600 °C with the advantage of an industrially proven and up-scalable manufacturing technique. We show manufacturing of 25 cm 2 BZCY half-cells by tape-casting of assemblies with electrolyte thickness 10-20 μm. BaY 2 NiO 5 transient liquid phase formation is analysed and proton conductivity with values of σ = 0.003 S cm −1 at 600 °C is shown.