High sintering activity Cu–Gd co-doped CeO2 electrolyte for solid oxide fuel cells

Nano-sized Ce0.79Gd0.2Cu0.01O2−δ electrolyte powder was synthesized by the polyvinyl alcohol assisted combustion method, and then characterized by crystalline structure, powder morphology, sintering micro-structure and electrical properties. The results demonstrate that the as-synthesized Ce0.79Gd0.2Cu0.01O2−δ was well crystalline with cubic fluorite structure, and exhibited a porous foamy morphology composed of gas cavities and fine crystals ranging from 30 to 50 nm. After sintering at 1100 °C, the as-prepared pellets exhibited a dense and moderate-grained micro-structure with 95.54% relative density, suggesting that the synthesized Ce0.79Gd0.2Cu0.01O2−δ powder had high sintering activity. The powders made by this method are expected to offer potential application in intermediate-to-low temperature solid-oxide fuel cells, due to its very low densification sintering temperature (1100 °C), as well as high conductivity of 0.026 S cm−1 at 600 °C and good mechanical performance with three-point flexural strength value of 148.15 ± 2.42 MPa.