Dense/Porous Asymmetric-Structured Oxygen Permeable Membranes Based on La0.6Ca0.4CoO3 Perovskite-Type Oxide

To achieve high-efficiency oxygen permeation using mixed (ionic and electronic) conducting perovskite-type oxides, we examined asymmetric-structured membranes of La0.6Ca0.4CoO3 in which a thin dense membrane was deposited on a porous support. The La0.6Ca0.4CoO3 porous support was fabricated using irregular-shaped precursor particles prepared through an oxalate method. The fabricated support had good gas permeability and thermal stability, showing sufficient properties as a support for dense thin membranes. A dense membrane of 10 mu m thickness was successfully formed on the porous support by coating a La0.6Ca0.4CoO3 Slurry and subsequent densification by sintering. The deposited thin membrane was gastight and free from clacks, as revealed by gas permeation tests and SEM observations. The asymmetric membrane exhibited a high oxygen permeability of 1.66 cm(3) (STP, standard temperature and pressure) min(-1) cm(-2) at 930 degrees C, which was four times higher than that of a typical sintered-disk type membrane with 1200/mu m thickness, demonstrating its feasibility as a high-performance oxygen separation membrane.