Powder and Electrical Properties of La0.6Sr0.4CoO3-δ Cathode Material Prepared by a Modified Sol-Gel Method for Solid Oxide Fuel Cell Application

Abstract

The powder properties and electrical conductivity of lanthanum strontium cobalt oxide, La0.6Sr0.4CoO3-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.