Structural and transport properties of nanostructured cathodes for intermediate-temperature solid-oxide fuel cells

DIEGO GERMAN LAMAS; LEANDRO MARCELO ACUÑA; AUGUSTO ENRIQUE MEJÍA GÓMEZ; MARÍA BELÉN VIGNA; EDUARDO QUEZADA LÓPEZ; JOAQUÍN SACANELL; MÁRCIA CARVALHO DE ABREU FANTINI

Campinas

Encuentro; Annual users meeting LNLS; 2014

LNLS/CNPEM

Fuel cells are one of the most promising technologies for environmentally‐friendly and high‐ efficiency power generation. Among them, solid‐oxide fuel cells (SOFCs) have the unique capability to use different fuels such as hydrocarbons or hydrogen. However, several issues have to be overcome in order to reduce the operation costs.  The reduction of their high  operating temperatures, typically around 900‐1000ºC, is one of the most important ones. For this reason, extensive research work has been conducted in order to find novel materials to produce SOFCs capable to work at intermediate temperatures (IT‐SOFCs). Cathodes based on mixed ionic/electronic conductors (MIECs) have received great attention because the active sites for the oxygen reduction reaction extend the whole surface of the cathode, while in conventional electronic conducting materials it only takes place in the[oxygen/cathode/electrolyte] triple phase boundaries  (TPBs).In the last years, our research group proposed a novel family of high‐performance cathodes based on nanostructured MIECs, mainly cobaltites and cobalto‐ferrites of perovskite‐type structure, dramatically increasing the number of active sites. In this work, we present high‐ temperature XPD and XANES studies on nanostructured MIEC cathodes, under operating conditions, and correlate them with the transport and electrocatalytical properties. In particular, we will discuss the retention of the high‐performance cubic phase in nanocrystalline cobaltites.