Enhancing commercial SOFCs fed directly with ethanol through a modified manganite coating

In this paper, we propose a novel approach to solve the problem of the fast decay of commercial Solid Oxide Fuel Cells (SOFCs) when directly fueled with dry ethanol. A Nickel Manganite of Lanthanum and Strontium (LSMN−La1.5Sr1.5Mn1.5Ni0.5O7±δ) material is used as a coating layer applied to the conventional Ni anode, aimed at modifying the ethanol fuel and suppressing both its craking and carbon deposition that usually occurs on Ni anodes. A thorough electrochemical analysis of the cell at 700 °C, including a durability test, polarization curves (I-V), and Electrochemical Impedance Spectroscopy (EIS) measurements, revealed that the LSMN-modified anode exhibits high stability. As shown by the decreased diffusion constraint observed in the I-V curves after prolonged operation, as well as the presence of three semicircles in the EIS spectrum. This behavior is explained by the occurrence of the so-called shuttle mechanism, which is expected to simplify deeply the fuel access into the Ni anode. Structural analysis of the LSMN coating using X-ray Absorption Spectroscopy demonstrated that the perovskite structure of the as-prepared specimen is modified due to Ni exsolution and the partial Mn reduction occurring under operating conditions. Despite the modification taking place on the original perovskite structure, suggesting new Mixed Ionic-Electronic Conduction (MIEC) properties for the LSMN, the experimental evidence presented in this paper proved the effectiveness of the approach of coating commercial SOFCs anode with specific active materials to improve performance.