The effects of doped Nd on conductivity and phase stability of BaCe0.8Y0.2O3−δ-based electrolyte for solid oxide fuel cell

This study investigates the structure, phase stability, and electrical properties of BaCe0.8Y0.2−xNdxO3−δ (x=0–0.2) in humid air. XRD results indicate that a BaCe0.8Y0.2−xNdxO3−δ sample has an asymmetric orthorhombic structure, and this structure becomes more symmetric as the amount of Nd doping increases. The conductivity of BaCe0.8Y0.2−xNdxO3−δ depends on the amount of Nd doping and the operation temperature. AC impedance results indicate that the resistance of BaCe0.8Y0.2−xNdxO3−δ decreases as the temperature increases, with the majority of resistance coming from oxygen ion diffusion. The XRD peak intensity of BaCe0.8Y0.2O3−δ apparently decreased with time, forming Ba(OH)2 and CeO2 second phases. The phase stability of BaCe0.8Y0.2−xNdxO3−δ (x=0.05–0.2) samples is much better than that of BaCe0.8Y0.2O3−δ, and it exhibited no second phase after tested in an 80°C water bath for 18h.