A novel lanthanum strontium cobalt iron composite membrane synthesised through beneficial phase reaction for oxygen separation

Abstract

Abstract Composite ceramic membrane is one of the most attractive concepts which combines the advantages of different phases into a single membrane matrix. Recently, the reported significant increased oxygen surface kinetics on the Perovskite/Ruddlesden-Popper composite system because of the formation of novel and fast oxygen transport paths along the hetero-interface has been implanted into the oxygen permeation membrane system. In this work, a novel La0.6Sr0.4Co0.2Fe0.8O3-δ-(La0.5Sr0.5)2CoO4+δ (LSCF-LSC) composite hollow fiber membrane is synthesized with oxygen permeation flux of 4.52 mL min−1 cm−2 at 950 °C. It presents round 4 times and 2.3 times of that of the single LSCF membrane and LSC-coated LSCF membrane at 900 °C. For better comparison, (La0.576Sr0.424)1.136Co0.3Fe0.7O3-δ (LSCF-new) is prepared based on the composition of LSCF-LSC composite. The enhanced oxygen permeability was further investigated through electrochemical impedance spectroscopy (EIS) measurements. We also confirm that LSCF-LSC shows significantly lower area specific resistance (ASRs) for LSCF-LSC|Ce0.8Sm0.2O1.9 (SDC)|LSCF-LSC symmetrical cell relative to other symmetrical cells. This novel LSCF-LSC composite membrane also presents high CO2 tolerance, with stable oxygen permeation fluxes round 2.6 mL min−1 cm−2 at 900 °C for 100 h.