Copper Doped La0.8Sr1.2FeO4Ruddlesden-Popper SOFC Cathode: Synthesis, Characterization and Model Analysis

Novel La0.8Sr1.2Fe0.9Cu0.1O4±δ (LSFC) oxides for application as cathodes in SOFCs were prepared with two different synthetic methods: solid‐state‐reaction (SSR) and molten citrate (MC). The XRD, ICP‐OES, SEM, laser granulometry and TG‐DTA techniques were applied for the physico‐chemical characterization. 4‐points DC conductivity measurements and EIS experiments were performed in the electrochemical characterization. Compared to SSR, the MC method allowed to obtain finer powders (∼2 μm vs. ∼5 μm) and required lower calcination temperatures (1,000 °C vs. 1,400 °C). The SSR and MC samples showed similar conductivity (30 S cm−1 at 700 °C) and polarization resistance (1.7 Ω cm2 at 700 °C). The EIS results were analyzed with the equivalent circuits method, and with a physically‐based model for the simulation of the impedance spectra, which indicated that the oxygen reduction mechanism involved the TPB. The MC method revealed preferential, thanks to the lower calcination temperature.