Dense/porous asymmetric-structured oxygen permeable Membranes based on la_0.6Ca_0.4CoO₃ perovskite-type oxide

To achieve high-efficiency oxygen permeation using mixed (ionic and electronic) conducting perovskite-type oxides, we examined asymmetric-structured membranes of La_0.6Ca_0.4CoO₃ in which a thin dense membrane was deposited on a porous support. The La_0.6Ca _0.4CoO₃ 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 μm thickness was successfully formed on the porous support by coating a La_0.6Ca_0.4CoO₃ 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 cm³ (STP, standard temperature and pressure) min^-1 cm^-2 at 930 °C, which was four times higher than that of a typical sintered-disk type membrane with 1200 μm thickness, demonstrating its feasibility as a high-performance oxygen separation membrane.