Perovskite-structured cathode material containing samarium (Sm) has been recognized as a promising electrode material due to its high electrocatalytic property for intermediate temperature-operating solid oxide fuel cell (IT-SOFC). This research investigated the optimized composition of (Co,Fe,Ni) on the electrolyte and the possible use of an optimized composite material for the IT-SOFC system. The electrochemical and thermal properties of (Co,Fe,Ni) and its composite material with the electrolyte were investigated in terms of area specific resistance (ASR) and thermal expansion coefficient at various temperature conditions. Durability of the selected materials was verified by thermal cycling and long-term degradation tests. and the (6:4) composite cathode showed a very low ASR of and at , respectively. The composite type cathode for the material was more attractive due to its thermal expansion compatibility with neighboring cell components.