화학공학소재연구정보센터
Materials Research Bulletin, Vol.72, 306-315, 2015
Effect of'A'-site non stoichiometry in strontium doped lanthanum ferrite based solid oxide fuel cell cathodes
Effect of A-site non-stoichiometry in strontium doped lanthanum cobalt ferrite (La1-xSrxCoyFe1-yO3-delta, x= 0.4; y= 0.2) is studied in a systematic manner with variation of 'A' site stoichiometry from 1 to 0.94. The perovskite based cathode compositions are synthesized by combustion synthesis. Powder characterizations reveal rhombohedral crystal structure with crystallite size ranging from 29 to 34 nm with minimum lattice spacing of 0.271 nm. Detailed sintering studies along with total DC electrical conductivities are evaluated in the bulk form with variation of sintering temperatures. The electrode polarizations are measured in the symmetric cell configuration by impedance spectroscopy which is found to be the lowest (0.02 Omega cm(2) at 800 degrees C) for cathode having highest degree of 'A'-site deficiency. The same cathode composition exhibits a current density of 2.84 A cm(-2) (at 0.7V, 800 degrees C) in anode-supported single cell. An attempt has been made to correlate the trend of electrical behaviour with increasing 'A'-site deficiency for such cathode compositions. (C) 2015 Elsevier Ltd. All rights reserved.