Effect of GDC addition method on the properties of LSM–YSZ composite cathode support for solid oxide fuel cells

Abstract

Equal amounts of Gd0.1Ce0.9O2−δ (GDC) were added to La0.65Sr0.3MnO3−δ/(Y2O3)0.08(ZrO2)0.92 (LSM/YSZ) powder either by physical mixing or by sol–gel process, to produce a porous cathode support for solid oxide fuel cells (SOFCs). The effect of the GDC mixing method was analyzed in view of sinterability, thermal expansion coefficient, microstructure, porosity, and electrical conductivity of the LSM/YSZ composite. GDC infiltrated LSM/YSZ (G-LY) composite showed a highly porous microstructure when compared with mechanically mixed LSM/YSZ (LY) and LSM/YSZ/GDC (LYG) composites. The cathode support composites were used to fabricate the button SOFCs by slurry coating of YSZ electrolyte and a nickel/YSZ anode functional layer, followed by co-firing at 1250°C. The G-LY composite cathode-supported SOFC showed maximum power densities of 215, 316, and 396mWcm−2 at 750, 800, and 850°C, respectively, using dry hydrogen as fuel. Results showed that the GDC deposition by sol–gel process on LSM/YSZ powder before sintering is a promising technique for producing porous cathode support for the SOFCs.