Interlayer-free nanostructured La0.58Sr0.4Co0.2 Fe0.8O3-delta cathode on scandium stabilized zirconia electrolyte for intermediate-temperature solid oxide fuel cells

Abstract

LSCF powders with a specific surface area of 25.2 m(2) g(-1) and an average particle size of 89 nm a resynthesized by the polymerizable complex method. The use of nanocrystalline LSCF powders allows the fabrication of an interlayer-free nanoporous cathode on top of an ScSZ electrolyte at a low temperature at which non-electrocatalytic secondary phases cannot form. The electrochemical performance of the interlayer-free cathode depends largely on the sintering temperature. A cathode sintered at below 750 degrees C lacks sufficient mechanical adhesion to the electrolyte, while the electrode surfaces are locally densified when sintered at above 800 degrees C. Impedance spectroscopy combined with microstructural evidence reveals that the optimum sintering temperature for LSCF is 750 degrees C. This avoids excess densification and grain growth, and results in the lowest polarization resistance (0.048 Omega cm(2) at 750 degrees C). (c) 2008 Elsevier B.V. All rights reserved.