Electrophoretic Deposition and Characterization of Er-Doped Bi2O3 Cathode Barrier Coatings on Non-conductive Ce0.8Sm0.2O1.9 Electrolyte Substrates

In this study the formation of thin-film barrier coatings based on a highly-conducting Bi1.60Er0.4O3 (EDB) solid electrolyte on supporting Ce0.8Sm0.2O1.9 (SDC) electrolyte substrates is implemented for the first time using electrophoretic deposition (EPD). Electrokinetic properties of EDB-based suspensions in a non-aqueous dispersion medium of isopropanol modified with small additions of polyethyleneimine (PEI, 0.26 g/L) and acetylacetone (0.15 g/L), as well as in a mixed isopropanol/acetylacetone (70/30 vol.%) medium are studied. The dependences of the thickness of EDB coatings on voltage and deposition time are obtained using deposition on a model Ni-foil electrode. Preliminary synthesis of a conductive polypyrrole (PPy) polymer film is used to create surface conductivity of non-conductive SDC substrates. The efficiency of using a modified dispersion medium based on isopropanol to obtain a continuous EDB coating 12 μm thick, sintered at a temperature of 850 °C for 5 h, is shown. The microstructure and morphology of the surface of the EDB coating are studied. Pt/SDC/EDB/Pt cell is used to characterize the coating conductivity. The EPD method is shown to be promising for the formation of barrier coatings based on doped bismuth oxide. The developed method can be used for creating cathode barrier layers in SOFC technology.