Influence of a La0.6Sr0.4CoO3-δ Functional Layer on (Ba0.5Sr0.5)(Co0.8Fe0.2)O3-δ Oxygen Transport Membranes (OTMs)

Nanoporous La0.6Sr0.4CoO3-δ (LSC) thin films with a thickness between 100 and 500 nm were derived from metal-organic precursors. These layers were applied onto a thin Ba0.5Sr0.5Co0.8Fe0.2O3-δ substrate (thickness ≈ 400 µm) in order to enhance oxygen surface exchange. The surface exchange coefficient kδ of uncoated and LSC-coated dense BSCF ceramic bulk samples were determined by electrical conductivity relaxation (ECR) measurements. By combining the results from these ECR measurements under varying oxygen partial pressures with transmission electron microscopy (TEM) analyses the influence of the nanostructured functional LSC layer on the dense BSCF ceramic membrane was investigated and discussed. Elemental distributions before and after aging obtained by analytical scanning TEM were carried out to address cation interdiffusion between LSC and BSCF.