Synthesis, structural analysis and electrochemical performance of low-copper content La2Ni1−xCuxO4+δ materials as new cathodes for solid oxide fuel cells

In order to enhance the electrochemical performance of solid oxide fuel cells (SOFCs), La2Ni1−xCuO4+δ (x = 0, 0.01, 0.02, 0.05 and 0.1) doped with copper in percentages, varying between 1% and 10%, were prepared following the modified Pechini method. The microstructure and morphology of the samples were analyzed by XRD and SEM. The electrochemical performance was followed by impedance spectroscopy. La2Ni0.99Cu0.01O4+δ samples showed good electrochemical and physicochemical properties with respect to the undoped material and is potentially a promising cathode. Indeed, doping with such small amounts of copper (1%) into the nickel site led to the formation of pure phases and stabilized the material before and after use at high temperature under air. In contrast, doping with higher amounts of copper (2%, 5% and 10%) led, after heating at 1000 °C for 48 h, to the formation of another phase resulting from the diffusion of copper into the YSZ electrolyte, limiting the interest to these materials as SOFC cathodes.