Ce_(0.8)Gd_(0.2)O2 modification on La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O3 cathode for improving a cell performance in intermediate temperature solid oxide fuel cells

摘要

To increase the cell performance of solid oxide fuel cells operated at intermediate temperature (600-800 °C), Ce_(0.8)Gd_(0.2)O2 (GDC) was applied to the La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O3(LSCF) cathode in electrode microstructure using sol-gel coating. We employed a GDC as a diffusion barrier layer on the yttria-stabilized zironia (YSZ) electrolyte to prevent the interlayer formation of SrZrO3, which has poor ionic conductivity. This interfacial reaction product was hardly formed at the electrolyte-cathode interlayer after sintering the GDC layer resulting to reduce the cathode polarization resistance. Moreover, we use sol-gel method to coat GDC thin layer through the cathode pore wall surface to extend the triple phase boundary (TPB) area. The cathode polarization resistance also reduced due to the additional TPB area. For the single cell featuring LSCF cathode modified with GDC sol-gel coating, the maximum densities were 0.41 W/cm~2 and 0.89 W/cm~2 at 700 °C and 800 °C.