Impact of Ni-GDC fuel electrode microstructure on cell performance in fuel electrode-supported solid oxide cells

The performance of nickel gadolinium-doped ceria (Ni-GDC) electrodes was evaluated in a cell with a thick (∼300 μm) nickel yttria-stabilized zirconia (Ni-YSZ) support and a thin (∼10 μm) ScYSZ electrolyte. This design offers an alternative to traditional Ni-YSZ fuel electrode-supported cells, which degrade rapidly at high overpotentials and/or current densities. Several variations were tested, including the NiO/GDC ratio, powder properties, and sintering temperature to improve initial performance. Electrochemical Impedance Spectroscopy (EIS) and current-voltage (IV) measurements were used for evaluation. Symmetrical Ni-GDC and LSC-GDC cells confirmed that most polarization losses in full cells originate from the Ni-GDC fuel electrode, particularly at the electrode-electrolyte interface. Enhancing the electrode-electrolyte interface with GDC proved the most effective approach to boost initial performance, producing a cell with an area-specific resistance (ASR) of 0.26 Ω cm 2 at 800 °C, 50/50H 2 O/H 2 and air at OCV. This ASR is slightly higher than that of state-of-the-art solid oxide electrolysis cells based on Ni-YSZ electrodes. The study demonstrates that improving electrode-electrolyte contact and lowering co-sintering temperature are effective strategies to enhance performance. • Four different Ni-GDC fuel electrode-supported cells are fabricated and characterized. • GDC enrichment at the interface reduces electrode polarization resistance. • Co-sintered cells at 1200 °C are gas-tight and electrochemically testable. • Symmetrical cell tests attribute most R p to the fuel electrode side. • Porous and mixed GDC–ScYSZ interface increases interfacial resistance and losses.