Material Characteristics and Electrochemical Performance of YxBa2-XCo2O5+δ Cathode for Solid Oxide Fuel Cell

A new Y_xBa_2-xCo₂O_5+δ cathodes were successfully prepared by solid-state reaction method. The structure, microstructure, conductivity, coefficient of thermal expansion and electrochemical properties of these Y_xBa_2-xCo₂O_5+δ cathodes were conducted by XRD, SEM, 4 DC four-terminal method, thermomechanical analysis and AC impedance, respectively. The YBaCo₂O_5+δ is a single phase with double perovskite structure. The second phases of YBa₂Co₃O_9-δ and Y₂O₃ were observed as the x>1 and x<1, respectively. The conductivity of all Y_xBa_2-xCo₂O_5+δ amples increased as temperature increased, and show a p-type conductor characterization. The YBaCo₂O_5+δ exhibited a maximum conductivity of 256 S/cm at 300 ^oC. The coefficient of thermal expansion is 13.8*10^-6, which is close to that of Samaria-doped Ceria (SDC) electrolyte. The YBaCo₂O_5+δdid not react with SDC electrolyte below 1050 ^oC. The YBaCo₂O_5+δ is a potential cathode material for intermediate temperature solid oxide fuel cell.