A Mixed Ionic and Electronic Conducting Dual-Phase Membrane with High Oxygen Permeability

To combine good chemical stability and high oxygen permeability, a mixed ionic-electronic conducting (MIEC) 75wt% Ce0.85Gd0.1Cu0.05O2--25wt% La0.6Ca0.4FeO3- (CGCO-LCF) dual-phase membrane based on a MIEC-MIEC composite has been developed. Copper doping into Ce0.9Gd0.1O2- (CGO) oxide enhances both ionic and electronic conductivity, which then leads to a change from ionic conduction to mixed conduction at elevated temperatures. For the first time we demonstrate that an intergranular film with 2-10nm thickness containing Ce, Ca, Gd, La, and Fe has been formed between the CGCO grains in the CGCO-LCF one-pot dual-phase membrane. A high oxygen permeation flux of 0.70mLmin(-1)cm(-2) is obtained by the CGCO-LCF one-pot dual-phase membrane with 0.5mm thickness at 950 degrees C using pure CO2 as the sweep gas, and the membrane shows excellent stability in the presence of CO2 even at lower temperatures (800 degrees C) during long-term operation.