With the aim to characterize the impact of an interfacial layer of Ca3Co4O9+d cathode material on the electrochemical performances of a symmetric cell made of a cerium gadolinium oxide (CGO) electrolyte and 50 wt.% Ca3Co4O9+d - 50 wt.% CGO porous electrodes, conditions of thin film deposition by pulsed laser deposition were optimized. The beneficial impact of such an interfacial layer was confirmed by impedance spectroscopy which showed, for cells prepared in the same conditions, a division by a factor of two of the area specific resistance when a thin layer of Ca3Co4O9+d was introduced between the electrolyte and the electrodes.