Abstract : GdBaCo2O5+δ has been recently introduced as a potential cathode material for solid oxide fuel cell. However, its utilization has been strongly limited by its chemical reactivity with yttrium-stabilized zirconia and its significant thermal expansion coefficient. This work focus on the study of compounds GdBaCo2 xMxO5+δ (M = Ni, Fe, x = 0, 0.1, 0.2...) i.e. substituted by Ni or Fe in order to ameliorate the properties of original composition for fuel cell application. Firstly, different synthesis methods have been attempted and compared, and the chemical routes showed a clear advantage for obtaining high substitution proportion. The physico-chemical properties of synthesized materials have been characterized. The structure of these compounds evolves with the substitution nature and proportion, while their properties such as electrical conductivity or changes in the oxygen content are relatively constant. Finally, the electrochemical performances of several compositions serving as porous electrodes were tested with different types of electrolytes. The results exhibit that the substitution neither shows evident influence with respect to the thermal expansion of these compounds, nor significantly improves their electrochemical performance.