Improving the electrical property of CeO2-containing sealing glass-ceramics for Solid Oxide Fuel Cell applications: Effect of HfO2

The electrical property of sealing glass-ceramics is of great importance for Solid Oxide Fuel Cell (SOFC) applications. In spite of their good sintering property, CeO2-containing glass-ceramics often lack in sufficient electrical resistance, due to the formation of CeO2 as a conductive phase. Here we report for the first time that the electrical conductivity of CeO2-containing glass-ceramics can be reduced by an order of magnitude with HfO2 dopant. A mechanism on the improved electrical property has also been proposed in terms of the structural change in HfO2-doped glass-ceramics. In addition, the relationship between phase evolution of HfO2-doped glass-ceramics and the change in conductivity with operational time has been systematically investigated. Moreover, HfO2-doped glass-ceramics show good chemical compatibility with 8 mol.% yttria-stabilized zirconia (8YSZ) electrolyte, after held at 750 °C for 500 h. The reported results support the suitability of prepared glass-ceramics as sealing materials for SOFC applications.