Perovskite type La(1-x)Sr(x)Ni(y)Fe(1-y)O(3-delta) (x = 0 3 04 0 5 0 6 y = 0 2 x = 0 3 y = 0 2 0 3 0 4) oxides have been synthesized and employed as cathodes for low temperature solid oxide fuel cells (SOFCs) with composite electrolyte The segregation of La(2)NiO(4 +/-delta) is observed to increase with the increasing Sr(2+) incorporation content according to X ray diffraction (XRD) results The as prepared powders appear porous foam like agglomeration with particle size less than 1 gm Maximum power densities yield as high as 725 mW cm(-2) and 671 mW cm(-2) at 600 C for fuel cells with the LSNF4628 and LSNF7337 composite cathodes The maximum power densities continuously increase with the increasing Sr(2+) content in LSNF cathodes, which can be mainly ascribed to the possible charge compensating mechanism The maximum power densities first increase with the Ni ion incorporation content up to y =0 3 due to the increased oxygen vacancy ionic conductivity and oxygen permeability Further increase in Ni ion content results in a further lowering of fuel cell performance which can be explained by the association of oxygen vacancies and divalent B site cations in the cathode (C) 2010 Professor T Nejat Veziroglu Published by Elsevier Ltd All rights reserved