Addition effects of bismuth oxide on Samaria-doped ceria based lithium carbonate composite electrolytes for intermediate temperature-solid oxide fuel cells

The effect of amounts (3, 5, 10, 20 wt%) of Bi2O3 on the sintering characteristics and porosity of Samaria-doped Ceria (SDC) based Lithium carbonate has been evaluated. The density had a maximum as high as 98.5% of theoretical density at 800°C with only 1wt%Li2CO3 and 3 wt%Bi2O3. The composite electrolytes showed high ion conductivity at evaluated temperatures. Composition and calcination temperature were found to affect the morphology and conductivity of the composite electrolytes greatly. The total conductivity closed to 3 orders of magnitude greater than pure SDC at operating temperature of 900°C and 3.5 orders of magnitude greater than pure SDC at operating temperature of 600°C. Especially, the best sample containing 3 wt% Bi2O3 sintered at 800°C for 2 h which had an ionic electrical conductivity of 0.17S cm−1. According to fuel cell performance, these composite electrolytes are chemically stable, which is an attractive prospect in intermediate temperature solid oxide fuel cell applications.