Solid oxide fuel cell composite cathodes prepared by infiltration of copper manganese spinel into porous yttria stabilized zirconia

Composite cathodes of Cu(1.25)Mn(1.75)O(4) (CMO) spinel and yttria stabilized zirconia (YSZ) were made by infiltration of a precursor Cu-Mn gel into a porous YSZ matrix. Structural characterization showed no evidence of secondary phases but revealed a continuous network of CMO in the YSZ framework. Impedance spectroscopy and overpotential measurements revealed that the CMO-YSZ composite cathode had better electrochemical performance than the traditional LSM-YSZ cathode between 650 and 800 degrees C. A 50 wt% CMO impregnated YSZ cathode had a polarization resistance of 0.3 Omega cm(2) at 750 degrees C, compared to 8.5 Omega cm(2) for LSM-YSZ. Further investigation showed that charge transfer is the probable rate determining step for oxygen reduction in the CMO-YSZ cathode above 750 degrees C.