FABRICATION AND ELECTROCHEMICAL PROPERTIES OF GRADIENT-STRUCTURED SDC ELECTROLYTE LAYERS ON POROUS LSM CATHODE SUBSTRATE

摘要

It is well known that the microstructure of electrolyte/cathode interface is a major factor that affects electrochemical properties of solid oxide fuel cells (SOFCs).In the present paper, we report our recent work on, firstly, the fabrication of cathode-supported Ce0.8Sm0.2O1.9 (SDC) electrolyte transition layer with gradient structures stretching into a porous La0.8Sr0.2MnO3 (LSM) cathode via gas-controlled convection-diffusion codeposition and then, the fabrication of dense SDC electrolyte thin films by screen printing. The SDC films with a dense layer of～25μm and gradient layer of～35μm, have been fabricated on the porous LSM cathode substrates. The AC impedance spectra for SDC electrolyte on porous LSM cathode with and without gradient structures are presented. The interface polarization resistances at 973K were 0.911 Ωcm2 and 4.925 Ωcm2 with and without gradient structures, respectively, and, the apparent activation energy of interface conductivity with gradient structures is 118.95 kJmol-1, lower than 158.04 kJmol-1 without gradient structures.