La0.65Sr0.3MnO3-delta-YSZ cathodes are infiltrated with Sm0.6Sr0.4CoO3-delta (SSC) at 800oC using a precipitation method. The effect of SSC infiltration has been characterized for symmetric cells and single cells at reduced temperatures. With SSC addition the cathode polarization resistance, determined from symmetric-cell measurements, significantly decreases: from approx. 19.8 to 8.5 Omega cdot cm2 at 600oC, and from 7.7 to 3.3 Omega cdot cm2 at 650oC. Consequently, the single-cell performance with 97 percentH2+3 percentH2O fuel is dramatically improved, which may be attributed to the superior electrocatalytic activity of SSC in the cathodes.