Effect of Co doping on sinterability and protonic conductivity of BaZr0.1Ce0.7Y0.1Yb0.1O3−δ for protonic ceramic fuel cells

During the application of protonic ceramic fuel cells (PCFCs), Co species derived from Co-containing cathodes readily diffuse into electrolyte layer. In this study, the influence of cobalt doping on the sintering and protonic conducting properties of BaZr0.1Ce0.7Y0.1Yb0.1O3−δ (BZCYYb) electrolytes is evaluated. The Co-doped BZCYYb oxides prepared by a sol-gel way exhibit the orthorhombic perovskite structure. A trade-off relation between the sinterability and protonic conductivity of Co doped BZCYYb oxides is identified. Furthermore, BaZr0.1Ce0.68Y0.1Yb0.1Co0.02O3−δ (BZCYYbC2) with a compromise between sinterability and protonic conductivity is further applied as electrolyte of a single cell. The single cell with BZCYYbC2 electrolyte demonstrates a competitive power density of 0.67 W cm−2 at 700 °C.