The Influence of Doped Iron Oxide on the Performance of Ceria-Based Solid Electrolyte

The research of ceria-based electrolyte is of great significance for application of medium or low temperature solid oxide fuel cells. In this paper, Ce_0.8Gd_0.2O_2-δ (CGO) and CGO doped with 2.0 mol% FeO1.333 (2Fe–CGO) were synthesized by low-temperature combustion method, and the effects of doped iron oxide on density and conductivity were studied. The experimental results indicated that the relative density of 2Fe–CGO increased within a certain temperature range due to the occurrence of viscous flow sintering. It was found that Fe₃O₄ could clear SiO₂ impurities in the grain boundary, which can greatly enhance the conductivity of 2Fe–CGO. The conductivity of 2Fe–CGO was two orders of magnitude larger than CGO's when the test temperature was 250 °C.