Synthesis and characterization of fibrous La0.8Sr0.2Fe1-xCuxO3-δ cathode for intermediate-temperature solid oxide fuel cells

Aiming to offer a high-performance Co-free cathode for intermediate-temperature solid oxide fuel cells (IT-SOFCs), a series of La_0.8Sr_0.2Fe_1-xCu_xO_3-δ (LSFCux, x = 0.0–0.3) nanofiber cathodes were synthesized by the electrospinning method. The effects of various Cu doping amounts on the crystal structure, fiber morphology, and electrochemical performance of LSF nanofiber cathode materials were investigated. The results indicate that after being calcined at 800 °C for 2 h, the perovskite structure samples with a high degree of crystallinity are obtained. The morphology of electrospun nanofibers is continuous, and the average diameter of nanofibers is about 110 nm. In addition, the La_0.8Sr_0.2Fe_0.8Cu_0.2O_3-δ (LSFCu2) fiber cathode displays the optimal electrochemical performance, and the polarization resistance (R_p) is 0.674 Ω cm² at 650 °C. The doping of Cu transforms the main control step of the low-frequency band from dissociation of oxygen molecules to charge transfer on the electrode, and the maximum power density (P_m) of the Ni-SDC/SDC/LSFCu2 single cell reaches 362 mW cm^-2 at 650 °C.