Preparation and Characterization of Pr2-xSrxCoO4+δ Cathode Materials for IT-SOFC

The samples of Pr2-xSrxCoO4+δ (x=0.8, 1.0, 1.2) as cathode material for intermediate-temperature solid oxide fuel cell (IT-SOFC) were synthesized by solid-state reaction. Crystal structure, thermal expansion, electrical conductivity and electrochemical properties were investigated by XRD, SEM, dilatometry, DC four-probe method, AC impedance and cyclic voltammetry (CV) techniques, respectively. The XRD results showed all the samples obtained as a single K2NiF4-structural phase, there were no chemical reaction occurred between the Pr0.08Sr1.2CoO4+δ electrode and the Sm0.2Ce0.8O1.9 (SDC) electrolyte at 1100℃ in air. The thermal expansion coefficients (TECs) increased with Sr content increasing. The electrical conductivity of the specimens was over 100S/cm at 800℃. The polarization resistance decreased with the increasing of Sr content. Pr0.8Sr1.2O4+δ had the optimum value of 0.29Ω·cm2 at 700℃ in air.