Sputtered GDC Barrier Layers Enable High Performance and Durable 5 × 5 cm2 Solid Oxide Electrolysis Cells

Thin-film gadolinia-doped ceria (GDC) barriers deposited by magnetron sputtering offer a dense, interdiffusion-free alternative to conventional screen-printed layers, but their performance and durability in large-area, metallic testing environments remain largely undemonstrated. In this study, 5 × 5 cm2 SOECs incorporating either a sputtered or a screen-printed GDC barrier were fabricated and evaluated under stack-relevant electrolysis conditions. The sputtered GDC cell delivered a 27% higher current density at the thermoneutral voltage, attributed to a nearly 50% reduction in Ohmic resistance relative to the screen-printed counterpart. The long-term durability of the sputtered GDC cell was then assessed under galvanostatic electrolysis at 1.2 A/cm2, and post-test analysis confirmed that the GDC layer remained fully dense, well bonded to YSZ, and completely effective in blocking Sr migration across the entire active area after approximately 600 h of operation. Despite measurable performance degradation, losses originated from electrode-driven mechanismsNi restructuring and detachment at the hydrogen electrode, chromium poisoning within the oxygen electrode, and thermochemical decomposition of the oxygen electrode contact layerwhile the GDC barrier exhibited no structural or chemical failure. These results demonstrate that sputtered GDC not only lowers initial Ohmic resistance but also provides durable chemical protection in large-area SOECs, highlighting its suitability for future stack-scale systems.