Nickel-Gd-doped CeO₂ cermet anode for intermediate temperature operating solid oxide fuel cells using LaGaO₃-based perovskite electrolyte

Ni-CeO₂ doped with 20 mol.% Gd³⁺ (GDC) cermet was investigated as the anode of an intermediate temperature operating solid oxide fuel cell using LaGaO₃-based oxide electrolyte. It was found that the anodic overpotential decreased by mixing Ni with mixed electronic-ionic conductor, in-particular, mixing with doped CeO₂ is the most effective for decreasing the overpotential of the anode. Anodic overpotential became a minimum at 10 vol.% GDC to NiO. Using Ni-GDC cermet is also effective for improving the stability of the power density at the constant current output. Impedance analysis suggests that the improvement of anodic activity by mixing Ni with GDC was brought about by decreasing the diffusion overpotential, which was a result of the enlarged effective electrode area.