Synthesis and properties of CuO-doped Ce0.9Gd0.1O2−δ electrolytes for SOFCs

The effects of copper oxide (CuO) addition on the crystal structure, densification and microstructure of Gd-doped ceria (Ce0.9Gd0.1O2−δ, CGO) synthesized by the polymeric precursor method have been studied. Ce0.9−xGd0.1CuxO2−δ (0≤x≤0.01) precursor powders were calcined at 600°C for 1h and the phase formation was studied by powder X-ray diffraction combined with Rietveld refinement analysis. Relative density measurements and microstructural analysis were performed on pellets sintered in the temperature range 1000–1100°C in air. The effect of CuO as a sintering aid becomes more visible when its content is in the 0.5–1mol% range where the relative densities are found to be 98% for sintering temperature as low as 1000°C. A remarkable reduction (up to ~500°C) in the sintering temperature for 1mol% CuO-doped CGO ceramics is observed together with the formation of a dissolved phase of Gd2O3–CeO2–CuO. Ce0.89Gd0.1Cu0.01−yO2−δ sintered at 1000°C shows total electrical conductivity of 15.5mScm−1 at 600°C slightly higher than Ce0.9Gd0.1O2−δ sintered at 1500°C (12.4mScm−1). •Polymeric precursor method is a viable synthesis technique to prepare CuO-doped Ce0.9Gd0.1O2−δ solid solutions.•Cu2+ doping improves the sinterability of gadolinia-doped ceria.•98% Theoretical density is obtained after sintering at 1000°C.•Addition of 1mol% CuO has no detrimental effect on total electrical conductivity of CGO.