Influence of Preparative Techniques on Microstructure and Electrochemical Properties of Ba0.3Sr0.7Co0.6Fe0.4O3-δ(BSCF3764) Cathode for IT-SOFC

Abstract

Ba0.3Sr0.7Co0.6Fe0.4O3-δ(BSCF3764) was synthesized via three different methods; solid state reaction(SSR), glycine nitrate
process(GNP), and EDTA-citric acid complexing sol-gel method (SG). Effect of preparation techniques on XRD, microstructure, 4-probe DC conductivity and transport properties using EIS were studied. Both, phase formation temperature and time of BSCF3764 synthesized by SG was  found to be low as compared to other two methods. Grain size of around0.2-0.3 μm in case of SSR and grown grains with size of approximately 0.1-0.2 μm along with pinholes. Composition synthesized by SG showed  highest electrical conductivity at around 700 °C. The performance ofBSCF3764 cathode on GDC (8020) electrolyte was dependent on the synthesis technique. The ASR values of BSCF3764 prepared by SSR,GNP and Sol-gel were found to be 1.567, 0.931 and 0.548 cm2 at 700
°C. The cathode polarization resistance and activation energy was found to be minimum in BSCF3764 prepared by SG. The polarization resistance was found to be linearly dependent on oxygen partial pressure; Ea for variation of ASR with Po2 was lowest, 0.0028 eV, in composition synthesized via SG