Effect of Gd-doped ceria interlayer on the stability of solid oxide electrolysis cell

• Interlayer is used between Y0.16Zr1.84O2-δ electrolyte and La0.6Sr0.4Co0.2Fe0.8O3-δ.
• Gd0.2Ce0.8O2-δ (GDC) interlayer is coated either by sputtering or screen-printing.
• Stability of SOEC with three different interlayers is compared for 100 h.
• SOEC with pinhole-free GDC thin-film shows good stability during SOEC operation.
• Screen-printed GDC cannot prevent Sr segregation due to its porosity.

Gd0.2Ce0.8O2-δ (GDC) interlayers, positioned between La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) anode (air electrode) and yttria-stabilized zirconia (Y0.16Zr0.84O2-d, YSZ) electrolyte of solid oxide electrolysis cells (SOECs) to prevent mutual reaction, are compared that used either thin-film deposition method to produce dense layers or screen-printing to produce porous layers. Two cells with 2 μm-thick GDC layers are sputter deposited, one annealed at 1300 °C and the other at 1100 °C. During SOEC operation with an anodic current density of − 800 mA cm− 2 in 80% H2O + 20% H2 at 800 °C, the two cells show similar Ohmic and polarization resistances at the beginning of measurement, but the cell annealed at 1300 °C is more stable after 100 h than the film annealed at 1100 °C due to the stability of pinhole free nature of GDC layer. In a third cell with ~ 11 μm-thick screen-printed GDC layer, GDC is porous and therefore the cell degrades more rapidly during SOEC operation for 100 h than does a cell with ~ 2 μm-thick, pin-hole free GDC film. The good stability of the cell with dense, pin-hole free GDC thin film is attributed to its blocking of Sr.