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

Nano-sized Ce_0.79Gd_0.2Cu_0.01O_2-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 Ce_0.79Gd_0.2Cu_0.01O_2-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 Ce_0.79Gd_0.2Cu_0.01O_2-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.