Among available ways to enhance the SOFC cathode, optimizing their microstructure by making composites of two or more compounds is of considerable interest. This is due to intelligent use of each component properties to meet various characteristics in cathode electrodes. Many of the properties required for an electrode are created in composite mode and extended to the entire volume of the material. In this study, the effect of adding different weight percentages of Yittria-Stabilized Zirconia (YSZ) on the structural, electrical and electrochemical properties of (La 0.6 Ca 0.4 )(Fe 0.8 Ni 0.2 )O 3-? , (LCFN) composition is studied as an improved SOFC electrode. The LCFN sample is synthesized by a liquid mix method and its composition with YSZ is achieved by wet ball-milling. The investigation of the LCFN crystalline structure shows that its main phase is orthorhombic with Pnma space group, which is formed alongside a few impurity phases of CaO, NiO and Ni 2 FeO 4 . Also, milling in ethanol medium led to a proper mixture of LCFN and YSZ components. By examining chemical stability of the samples, it is revealed that the maximum temperature to prevent unwanted reaction products between calcium and zirconium in a two-phased composite is 850 °C. With increasing YSZ load, conductivities of compounds are reduced and lead to a shift in the maximum conductivity from 271.3 S/cm at 580 °C to 50 S/cm at around 750 °C. The activation energy of these compounds is also increased from 0.252 eV to 0.329 eV. It is observed that by adding YSZ load, the Area Specific Resistance (ASR) value of the LCFN which is about 0.0124 ?.cm 2 is reduced to 0.0080 ?.cm 2 for LCFN-YSZ-9010 sample. A further review of Electrochemical Impedance Spectroscopy (EIS) results shows that the presence of YSZ along with LCFN improves two processes of surface charge adsorption in the production of oxide ions, as well as the transfer of these ions into the cathode bulk due to the increase of Triple Phase Boundaries (T). The Distribution of relaxation Times (DRT) analysis performed on impedance spectra exhibits that gas traort and mass transfer are more dependent on oxygen partial pressure variations than ion traort process which is more affected by presence of YSZ ion conductive phase. The design of an SOFC with optimized cathode (LCFN-YSZ-9010) leads to an increase in open circuit voltage from 0.95 V to 1.04 V and also a rise in SOFC output power density from 420 mW/cm 2 up to 550 mW/cm 2 . As a result, the performance temperature of an SOFC using an improved cathode electrode is decreased at least 50 °C in this study.
