Powder and Electrical Properties of La_0.6Sr_0.4CoO_3-δ Cathode Material Prepared by a Modified Sol- Gel Method for Solid Oxide Fuel Cell Application

The powder properties and electrical conductivity of lanthanum strontium cobalt oxide, La_0.6Sr_0.4Co_O3-δ (LSC) material were systematically characterized with respect to application as cathode material for intermediate temperature solid oxide fuel cell (SOFC). The LSC was prepared via a modified sol-gel method assisted with a combination of ethylene glycol and activated carbon as a chemical additive. The decomposition of impurity compounds such carbon compounds and nitrates in the precursor powder was completed at 870°C as revealed by thermogravimetry (TG) analysis. As the calcination temperature increased from 800°C to 1000°C, the purity and crystallite size of the the calcined precursor powder also increased as confirmed by X-ray diffrcation (XDR) analysis. The micrograph of scanning electron microscope (SEM) image showed that the particle of the calcined powders form agglomeration and this led to low relative density (80.18%) of the sintered LSC pellet at 1200°C. The direct current electrical conductivities (σdc) of the sintered LSC pellet measured using Van der Pauw technique in air were 1504 S cm^-1 and 1069 S cm^-1 at 400°C and 800°C, respectively. The relatively high σdc with low activation energy (Ea) of 0.021 eV indicates that the LSC prepared in this work has a great potential to be used as a cathode material for intermediate temperature SOFC application.