Wet powder spraying fabrication and performance optimization of IT-SOFCs with thin-film ScSZ electrolyte

Abstract

We have successfully fabricated a dense-type Scandia-stabilized zirconia (ScSZ) thin-film electrolyte with thickness down to ∼4 μm for intermediate temperature solid oxide fuel cells (IT-SOFCs; 600–800 °C) by a wet powder spraying technique. With an anode-supported design and a La 0.8Sr 0.2Sc 0.1Mn 0.9O 3 (LSScM) oxide cathode, a peak power density of 788 mW cm −2 was achieved at 800 °C for a cell operating on hydrogen fuel. The impedance results demonstrated that the electrode polarization resistance is the main source of electrochemical performance loss for the single cell. Ba 0.5Sr 0.5Co 0.8Fe 0.2O 3−δ + Sm 0.2Ce 0.8O 1.9 (BSCF + SDC) composite cathode was then applied to improve the cell power output. An SDC interlayer was adopted to avoid the interfacial phase reaction between ScSZ and BSCF, which was also fabricated by the wet powder spraying. The effect of interlayer processing on the morphology and cell performance was studied by SEM-EDX, I– V polarization and EIS. Pre-sintering of the ScSZ layer was found to be superior to the co-sintering of SDC interlayer and ScSZ electrolyte layer. An anode-supported cell with SDC interlayer fabricated on pre-sintered ScSZ electrolyte film and a BSCF + SDC cathode delivered a peak power density as high as 1760 mW cm −2 at 800 °C.