Nanostructured MIEC Ba_(0.5)Sr_(0.5)Co_(0.6)Fe_(0.4)O_(3-δ) (BSCF5564) cathode for IT-SOFC by nitric acid aided EDTA-citric acid complexing process (NECC)

摘要

Ba_(0.5)Sr_(0.5)Co_(0.5)Fe_(0.4)O_(3-δ)(BSCF5564) was synthesized by nitric acid aided EDTA-citric acid complexing sol-gel method (NECC). Both, the phase formation temperature and time of BSCF5564 synthesized NECC were found to be low i.e. single perovskite phase formation temperature is 200 ℃ less as compared to the conventional method of synthesis. The orthorhombic perovskite structure has been formed after calcination at 800 ℃ for 5 h. Scanning electron microscopy reveals the formation of porous material constituting nano-sized and irregularly shaped rod-like structure with particle size approximately ranges from 90 to 160 nm. The total weight loss of the BSCF5564 sample comes out to be 6.6%, indicating that quadrivalence state Co~(4+) and Fe~(4+) in the sample have been completely reduced to the trivalent state Co~(3+) and Fe~(3+) due to thermal analysis. The value of E_a for BSCF5564 prepared by NECC was 0.2288 eV. The electrical conductivity of BSCF5564 synthesized by NECC is observed to be steady at high temperature (above 700 ℃).