Fuel cell is an electrochemical device that directly converts chemical energy of a fuel to electrical energy. All fuel cells consist of two electrodes, anode and cathode and an electrolyte. Solid Oxide Fuel Cells are a In this investigation, La 0.6 Ca 0.4 Fe 1-x Co x O 3 (0?x?0.5) was used as a cathode of solid oxide fuel cell by the method of Sol-gel. The 8% yttria stabilized zirconia (YSZ) was used as an electrolyte, because of its high ionic and low electrical conductivity. The analyzed X-ray diffraction (XRD) results demonstrate the desired structural phases of cathode. The doped cathodes did not have any noticeable impurity phase. . Electrical resistance measurement versus temperature of samples reveals that conductivity increase with Co doping and less activation energy achieved for sampel with x=0.5. Scanning electron microscope used to study the topography of the particles It reveals that doping cobalt results in a smaller particles size. To makeing symmetric cells (LCFC/YSZ/LCFC) spray coating method was used with heating electrolyte substrat. at the end, electrochemical impedance measurement used to study the contribution of grain and grain boundry in symmetric cells.
