Preparation of electrolyte foils La0.85Sr0.15Ga0.85Mg0.15O2.85 (LSGM) by means of tape casting

The oxide LaGaO3 with the perovskite structure is the most promising solid electrolyte used for solid oxide fuel cells (SOFCs). The powders La0.85Sr0.15Ga0.85Mg0.15O2.85 (LSGM) were prepared by means of solid state reaction. The pH values of water solution of the powders increase firstly, reach the maximum value, then decrease gradually with the prolongation of time. The LSGM powders prepared are very stable in the water so that they can be used to prepare slurries by using water as the solvent in order to prepare electrolyte films. The preparation of slurries is of great importance in the manufacturing process of LSGM foils by means of methods of tape casting, screen printing, slurry coating as well as spray coating. In the process of preparation of LSGM slurries, the PBMA-b-PMAS block copolymer (PEO/PMAA), polyvinyl alcohol (PVA), polyethylenglykol 200 (PEG), Agitan 280 and water were used as dispersant, binder, plasticizer, defoamer and solvent, respectively. The foils were made by tape casting. The results show that the foils are free of macro-defect, and can be bent. The densified LSGM foils were made after sintering at 1500 °C for 10-24 h.