Plasma-Sprayed (Bi(2)O(3))(0.705) (Er(2)O(3))(0.245) (WO(3))(0.05) Electrolyte for Intermediate-Temperature Solid Oxide Fuel Cells (IT-SOFCs)

Stabilized bismuth oxide material with fluorite structure (δ-Bi(2)O(3)) has been studied as a promising electrolyte material for intermediate temperature solid oxide fuel cells (IT-SOFCs) due to its high oxygen ion conductivity in mediate temperature. Especially, the ternary system Bi(2)O(3)-Er(2)O(3)-WO(3) is widely concerned for its high ionic conductivity and thermal stability. In this study, regarding its low melting point, the possibility to deposit dense Bi(2)O(3)-Er(2)O(3)-WO(3) ((Bi(2)O(3))(0.705) (Er(2)O(3))(0.245) (WO(3))(0.05), EWSB) electrolyte by plasma spraying was examined. It was confirmed that the sintered EWSB bulk presents a high ion conductivity of 0.34 S cm(−1) at 750 °C and excellent stability that indicates no structure transformation and conductivity degradation after annealing at 600 °C for 1000 h. The phase structure and cross-sectional microstructure of plasma-sprayed EWSB were characterized by XRD and SEM. Results showed that the as-plasma-sprayed EWSB presents a dense microstructure with well bonded lamellae. The XRD showed the formation of EWSB with δ-phase and a trace of β-phase, while the β-phase disappeared after annealing at 750 °C for 10 h. The deposited EWSB electrolyte presented the excellent ionic conductivity of 0.26 S cm(−1) at 750 °C which can be directly applied to SOFC at intermediate temperature.