The materials with structure have been studied in order to explore their potential use as cathodes for intermediate temperature solid oxide fuel cells. The introduction of Sr in the lattice produces an enhancement of the electric conductivity but is accompanied by a decrease of ionic transport species. Neutron powder diffraction data show a transition from orthorhombic to tetragonal symmetry with the incorporation of Sr in the sublattice. Excess oxygen determined by iodometric titration shows that strontium insertion generates a decrease of the interstitial oxygen. In order to avoid the concomitant decrease of the ionic conductivity, the system underwent heat treatments under high oxygen pressure (, ). As a result, the treated exhibited an increase of the amount of interstitial oxygens but with improved electronic properties. The polarization resistances measured for these materials vary between and in air at the temperature range of . This remarkable behavior enables us to propose this material as an alternative cathode for IT-SOFC.