Development of Anode-Supported Solid Oxide Fuel Cell by Sequential Tape-Casting and Co-Sintering

Abstract

Simple and cost-effective technologies to produce solid oxide fuel cells layers require control of thickness, homogeneity, and reproducibility. The manufacturing of a SOFC involves significant ceramic processing challenges to obtain layers with controlled microstructure. Currently, possibly the most common technique for large-scale production of SOFCs is the tape casting. In our study, a co-tape casting process was used to avoid delamination and ensure good adhesion between layers. The process consists of casting a thick anode tape of Ni/YSZ (60/40vol%) on top of a thin electrolyte tape of yttria-stabilized zirconia (YSZ). The slurries of both components were prepared using commercial ceramic powders, organic additives, and solvent. The starting materials were processed in a ball mill, to attain the appropriate homogeneity and viscosity for tape casting. A double doctor blade was used to control the thickness. Thermogravimetric and dilatometric analysis were performed to find the optimized heat treatment to remove the organics and densify the electrolyte while keeping a porous anode. The half-cells were then calcined and sintered at 1450°C/1h, with low heating and cooling rates to prevent cracks due to the different thermal expansion of the layers. The LSM cathode was then deposited by spin-coating and attached to the half-cell at 1100°C/1h. To verify the adhesion, thickness, and porosity of the layers, the sample was analyzed by scanning electron microscope. The electrochemical performance was evaluated by impedance spectroscopy and single cell tests under hydrogen and synthetic air. In this study we demonstrate a facile route to SOFC fabrication by co-casting and co-sintering, with relatively mild sintering conditions, with a good control of layer thickness, porosity and adhesion. Figure 1