Investigation of Cu/F co-doped Sr2Fe1.5Mo0.5O6−δ cathode for solid oxide fuel cells

Abstract

In this paper, a novel Cu/F co-doping strategy is proposed to modify the electrochemical performance of Sr₂Fe_1.5Mo_0.5O_6–δ (SFM) cathode for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The pristine SFM, Cu-doped Sr₂Fe_1.4Cu_0.1Mo_0.5O_6−δ (SFCM) and Cu/F co-doped Sr₂Fe_1.4Cu_0.1Mo_0.5O_5.9−δF_0.1 (SFCMF) powders were synthesized by acid-glycine combustion method, and the impacts of Cu/F co-doping on the performance of SFM cathode were investigated systematically. It's found that Cu-doped SFCM has higher oxygen vacancy content and electrical conductivity than the pristine SFM and Cu/F co-doped SFCMF cathodes. While the Coulombic force between B-sites metallic ions and oxygen ions are significantly weaken for SFCMF, enhancing the mobility of lattice oxygen. Due to the combined effects of Cu and F doping, SFCMF cathode exhibits the best electrochemical performance among all investigated samples. At 600 °C, the polarization resistant for SFCMF cathode is 1.79 Ω cm², decreased by 43.71 % in contrast to the parent SFM cathode. These results indicate that Cu/F co-doping is an effective strategy to improve the electrochemical properties of perovskite cathode materials.