Corn-cob like nanofibres as cathode catalysts for an effective microstructure design in solid oxide fuel cells

Abstract

An efficient cathode for solid oxide fuel cell (SOFC) is mainly determined by the oxygen reduction reaction (ORR) activity of the mixed materials. We demonstrate a new microstructure design through a nanofibrous electrode based on an unique corn-cob structure. One-step process to produce a corn-cob ceramic nanofiber of La0.8Sr0.2MnO3 (LSM) and Y2O3-stabilized ZrO2 (YSZ) is introduced by an electrospinning equipped with a coaxial nozzel. From the microscope analysis, perfect corn-cob nanofibers are finely produced with the diameter of 350 nm for a core and nanoparticles (30-40 nm) stacked on the surface like as a core-shell structure. The cathode fabricated by nanofibers with LSM outside and YSZ inside (YSZ@LSM) shows the best maximum power density of 1.15 Wcm-2 at 800 oC with low polarization resistance, which is higher than the reverse core and shell positions (LSM@YSZ) and even the commercial LSM-YSZ. This better outcome is more obvious at the elevated temperature due to the accelerated catalytic activity. Therefore, we could find the insight into the key factors enhancing the ORR activity and single cell performance in terms of not only the nanofibrous core@shell structure but also more reaction active sites from the optimum catalyst position at the designed corn-cob nanofibers based cathodes.