Investigation On Structures And Oxygen Chemical Diffusion Properties Of Perovskite Oxides (La_1-xPr_x)_0.6Sr_0.4Co_0.8Fe_0.2O_3-δ

Solid oxide fuel cell was a highly promising new energy conversion system which integrated with highlighting advantages such as energy-efficient, pollution-free. The operating temperature down to medium temperature range (600-800℃) are the major development direction of current study on SOFC.Cathode materials are the essential components of SOFC. It should cause the increasing of polarization overpotential and interfacial resistance If lowering the operating temperature of SOFC. Therefore, develop new type of cathode materials which good matching at electrolyte material was the premise and foundation of develop IT-SOFC.In this article, perovskite oxides of (La_1-xPr_x)_0.6Sr_0.4Co_0.8Fe_0.2O_3-δ(x= 0.2,0.4,0.6,0.8) samples were obtained by solid state-reaction method. The phase structure was analysed by XRD and Raman spectrum, the oxygen chemical diffusion properties was determined by electrical conductivity relaxation technique. The resultes show that dominant phase structure of LPSCF systems is perovskite structure, the octahedral CoO₆ was some distorted with increasing of content Pr, It is reflections of the presence of different secondary phase. the conductivity of (La_1-xPr_x) (0.6)Sr_0.4Co_0.8Fe_0.2O_3-δincreases with increasing of oxygen partial pressure. The(La_1-xPr_x)_0.6Sr_0.4Co_0.8Fe_0.2O_3-δsamples have higher oxygen chemical diffusion coefficients, which decrease linearity with the decreasing of temperature and increasing of content Pr. The oxygen chemical diffusion coefficients D_chen remains fairly constant at high PO₂. The oxygen chemical diffusion coefficients was highest at x=0.2, which achieved 9.41×10^-5cm²Â·s^-1 at 700℃, is comparatively potential cathodes material for intermediate temperature solid oxide fuel cells.