Economical preparation and characterization of dual-ion conducting fuel cell

Abstract

The composites consisted of oxygen ion conductive (La0.75Sr0.2Ba0.05)0.175Ce0.825O1.891 (LSBC) and proton conductive BaZr0.1Ce0.7Y0.2O3-δ (BZCY) prepared by solid state reaction and impregnation are sintered to form composite and phase gradient membranes, respectively. The conductivity of (100-x)LSBC-xBZCY composite membranes exhibit non-ohmic in air and semiconductive diode behavior in Ar/5%H2 higher than 500 °C. The elemental concentration gradient of Ba, Ce and O at grain boundaries of LSBC/BZCY corresponds to the inter-diffusion and Schottky barrier formation. The Schottky barrier of dual phase boundary (DPB) may be beneficial for dual-ion conduction. The microstructures of sintered and polished (100-x)LSBC-xBZCY surface exhibit convex hard LSBC and concave soft BZCY. The percolated 70LSBC-30BZCY of the composite membrane obtains the power density of 20.51 mW/cm2. The phase gradient membrane of BZCY impregnated LSBC presents the higher power density of 40.6 mW/cm2 (700 °C). The new two-phase composite and phase gradient membranes generate more simple and compact layer structure than sandwiched solid oxide fuel cell. Such two-phase dual-ion membranes provided by our economical process can be considered to develop new single membrane fuel cells possibly.