Properties of Ba0.5Sr0.5Co0.8Fe0.2O3-δ Composite Membrane

Abstract

The perovskite mixed ionic-electronic conducting membranes (MIEC) are widely used in solid oxide fuel cells, oxygen separation and the partial oxidation of methane to syngas. The synthesis process and properties of the composite membrane including the porous support layer and the thin dense layer with the same material, Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF5582), were investigated in the present study. The powders of perovskite structure BSCF5582 for porous support layer were synthesized by solid-state reaction method (SSR) at 1233 K for 2~6 hours, while the powders of BSCF5582 for dense layer were synthesized by citrate-EDTA complexing method (CC-EDTA) after being calcined at 1173 K for 2~6 hours. The support layer with a thickness of 0.6 mm was made by tape calendering process (TCP), and then pre-sintered at 1073 K for 1 h. The dense layer with a thickness of 30 μm was formed by dip-casting process. The composite membrane of BSCF was formed by co-firing the two layers at 1413 K for 10 hours. Porous support layer and dense layer were clearly identified by scanning electron microscopy (SEM). The conductivity of the composite membrane is 35S·cm-1 at 773K. The electrical-conduction behavior of BSCF obeys the p-type small polaron-hopping mechanism.