Thermal expansion and electrochemical properties of La{sub}0.7AE{sub}0.3Cu{sub}(3-δ) (AE=Ca, Sr, Ba) cathode materials for IT-SOFCs

摘要

Alkaline earth metals (Ca, Sr, Ba) substituted lanthanum copper oxides were investigated to evaluate their potentials as cathode materials for intermediate temperature solid oxide fuel cell (IT-SOFC). The crystal structure, thermal expansion and electrochemical performance of La{sub}(1-x)AE{sub}xCuO{sub}(3-δ) (x=0.3, AE=Ca, Sr, Ba) were studied by X-ray diffraction, thermal dilatometer and impedance spectra, respectively. By lowering the size of the A-site cation in ABO{sub}3 perovskite, a lower thermal expansion and polarization resistance were obtained for Ca-doped LaCuO{sub}(3-δ) cathode which showed an area specific resistance of 0.19 Ω cm{sup}(-2) under open circuit potential conditions at 800℃, and a polarization overpotential of 52 mV at a current density of 0.1 A/cm{sup}2 at 700℃, being a potential candidate of cathode material for IT-SOFCs.