Electrophoretic deposition of dense anode barrier layers of doped ZrO2 and BaCeO3 on a supporting Ce0.8Sm0.2O2-δ solid electrolyte: Problems and search for solutions in SOFC technology

This work is aimed at the formation of dense anode coatings of yttria-stabilized zirconia (YSZ) and samarium-doped barium cerate BaCe0.8Sm0.2O3-δ (BCS) on the Ce0.8Sm0.2O2-δ electrolyte to increase the performance of a single fuel cell on its base. Materials are obtained by precipitation from a nitrate solution (YSZ-disp), by laser vaporization-condensation (YSZ-lec) and citrate-nitrate method (BCS). YSZ and BCS coatings on SDC substrates were obtained by electrophoretic deposition (EPD) followed by sintering at 1300–1500 °C. Two methods are applied to ensure surface conductivity of the SDC substrates for successful EPD: by synthesizing a conducting polymer - polypyrrole and by depositing a buffer layer of finely dispersed Pt. The main problem of the formation of the dense YSZ layers on the SDC substrates has been revealed, which is associated with their delamination during high-temperature sintering due to thermal expansion mismatch. It is shown that the use of a Pt buffer sublayer makes it possible to avoid delamination during sintering at a temperature of 1500 °C. The BCS barrier layers are shown to be completely compatible with SDC. The influence of the YSZ and BCS barrier layers on the ohmic and polarization resistance values and the open circuit voltage (OCV) values is discussed.