Simultaneous A- and B- site substituted double perovskite (AA'B2O5+delta) as a new high-performance and redox-stable anode material for solid oxide fuel cells

Abstract

In this study, a novel PrBa0.5Sr0.5Fe2-xGexO5+delta (PBSFG) double perovskite is first introduced by the cosubstitution of Sr for A-sites and Ge for B-sites as a high-performance and redox-stable anode material for solid oxide fuel cells. The modification of the A-sites of PrBaFe2O5+delta by Sr-doping (PBSF) significantly enhances electrical conductivity of PBSF under a reducing atmosphere by several orders of magnitude at 800 degrees C. Subsequently, Ge-doping on B-sites leads to meaningful increases in oxygen ion conductivity of PBSFG, and is owing to increases in the oxygen vacancy concentration. The electrochemical performances of PBSFG-Ce0.9Gd0.1O2-delta (GDC) are evaluated using a composite anode with a GDC vertical bar Zr0.79Sc0.2Ce0.01O2-delta (ScSZ)IGDC electrolyte (similar to 100 mu m) and a La0.6Sr0.4Co0.2Fe0.8O3-delta (LSCF) cathode. The cell shows critical improvement in the maximum power density (838.4 mW cm(-2) at 800 degrees C) relative to the PrBaFe2O5+delta composite (497.6 mW cm(-2)). Moreover, it shows good redox-cycle stability from fuel to air under a current load.