SYNTHESIS AND CHARACTERIZATION OF LANTHANUM STRONTIUM COBALTITE POWDER USING A COMBINED CHEMICAL AGENT FOR PROTON CONDUCTING SOFC

Abstract

A modified sol-gel synthesis route was applied in the preparation of a single perovskite phase of lanthanum strontium cobaltite, La_0.6Sr_0.4CoO_3-δ (LSCO) for cathode application in proton conducting solid oxide fuel cell (SOFC). In this process, citric acid (CA) and ethylenediaminetetraacetic acid (EDTA) have been used as a combined chelating agent, while ethylene glycol (EG) and activated carbon (AC) have been used as a combined surfactant/dispersing agent. The amounts of AC to EG have been varied and the synthesized powders were characterized by X-ray diffractometer (XRD), particle size analyzer (PSA) and field emission scanning electron microscope (FESEM) equipped with energy dispersive X-ray (EDX) spectrometer. XRD results confirmed that a single LSCO perovskite phase formed at temperatures of 900 °C and 1000 °C. PSA and FESEM results revealed that the average particle size diameter of the produced powders increased as the ratio of AC:EG increased. The smallest average particle size diameters (19 nm) was obtained at 900 °C with ratio of 1:3 (AC:EG). EDX results showed that the calculated mole fraction of each element (La, Sr, Co) in the single phase powders were relatively closed to their nominal mole fraction, except for Sr. It can be concluded that the ratio of AC:EG affects the phase formation and average particle size diameter of LSCO powder.