Stability and performance of La0.6Sr0.4Co0.2Fe0.8O3-δ nanostructured cathodes with Ce0.8Gd0.2O1.9 surface coating

La0.6Sr0.4Co0.2Fe0.8O3-delta is considered as one of the most promising cathodes for Solid Oxide Fuels Cells (SOFCs) operating at intermediate temperatures, however, its performance degrades significantly over time mainly due to phase segregations on the surface. In this work, the surface of La(0.6)Sa(0.4)Co(0.2)Fe(0.8)O(3-delta) -Ce0.8Gd0.2O1.9 (LSCF-CGO) nanostructured cathode is coated with CGO particles via a simple and economic spray-pyrolysis deposition process. The electrode polarization resistance (Rp) and the microstructure evolution of the uncoated and CGO-coated cathodes are investigated by impedance spectroscopy and scanning electron microscopy, respectively. The CGO-coated cathodes exhibit improved stability and performance, with Rp values varying from 0.27 to 0.30 Omega cm(2) at an annealing temperature of 600 C-circle for 400 h. On the contrary, the uncoated cathode shows a faster degradation rate, with a continuous increase of Rp from 2.8 to 8.5 Omega cm(2). Above 800 C-circle, the particle coarsening of the CGO layer results in a significant increase of Rp over time, reaching steady values of 0.04 Omega m(2) at 800 C-circle. An anode supported cell with the CGO-coated cathode shows a remarkable power density of 0.72 Wcm(-2) at 650 C-circle in comparison to 0.56 Wcm(-2) for the cell with uncoated cathode. (C) 2017 Elsevier B.V. All rights reserved.