Manufacturing and performance of advanced supported Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF) oxygen transport membranes

Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF) is widely known as a promising candidate material for oxygen transport membranes (OTMs). In order to maximize the oxygen permeation through such a membrane, the membrane layer should be as thin as possible, which requires a porous support. Because of the expansion behavior of BSCF, porous supports of the same material were developed to avoid failure due to mismatches in the thermal expansion coefficients. For the purpose of minimizing concentration polarization in the support pores, the microstructure of these support-layers has been optimized. For that reason supports with a porosity of up to 41% were developed. Membrane curvature caused by different shrinkage rates during co-firing could be minimized by the use of corn starch as pore former. By increasing the support porosity from 26% to 41%, the oxygen permeation of a supported 20 μm membrane in an air–argon gradient at 800 °C was increased by 50%. Compared to a disc membrane of 0.9 mm thickness the permeation enhancement is 90%.

► Supported 20 μm membrane layers manufactured by sequential tape casting.
► Support porosity optimized (porosity >40%).
► Adjusting sintering behavior of supports by pore former leads to low deflection.
► Support still limits oxygen transport while using air as feed gas.
► Oxygen permeation rates up to 29 ml cm−2 min−1 at 900 °C achieved.