Exsolved perovskites for reliable SOFCs fed with dry biogas

In-situ exsolution can be used to generate fine nanoparticles on the surface of certain perovskites with novel properties that make them attractive candidates for use as anodes or protective layers in solid oxide fuel cells (SOFCs) fed with conventional fuels such as biogas. This study describes the fabrication and characterization of two exsolved perovskites, nickel manganite (LSMN) and nickel cobaltite (LSCN). However, the main objective of this study was to conduct a comparative analysis of electrochemical studies employing such exsolved perovskites as a coating layer on two button cells derived from the same large area commercial SOFC. A comparison of diagnostic results before and after prolonged operation showed that LSCN exhibited better performance due to its higher catalytic activity that simplified fuel via a mechanism called as "shuttle mechanism". This behaviour was particularly evident in the EIS experiment, which, throughout the experiment fell on a simplified spectrum of only 2 semicircles and a reasonable total resistance of 0.316 Ω cm2. Aside from performance that, in the case of LSCN, reached 0.68 W cm−2 @ 0.6V, such material appeared to be less affected by ohmic constraint due to its high reversibility. Nonetheless, as corroborated by the SEM reported in this paper, the superior advantage of using LSMN and LSCN as coatings in commercial SOFCs can be noticed in their ability to enhance the effectiveness of dry biogas-fed SOFCs by mitigating the formation of coke on the anode.