Low temperature sintering of BaZrO3-based proton conductors for intermediate temperature solid oxide fuel cells

Dense sintered bodies of the 15–25 mol% Yb-doped BaZrO3 could be obtained at a fairly low sintering temperature of 1500 °C, by the addition of 1.0 mol% CuO as a sintering aid. The crystal structures changed from orthorhombic (space group: Cmm2) to cubic (space group: Pm3m) by the CuO addition. The proton conductivity of thus-obtained 20 mol% Yb-doped BaZrO3 with the 1.0 mol% of CuO addition was 5.5 × 10− 3 S/cm at 600 °C under the wet nitrogen atmosphere, which was comparable to that of the 15 mol% Yb-doped BaZrO3 sintered at 1700 °C for 20 h without the CuO addition.