Cathode Properties of SmxSr1−x(Co,Fe,Ni)O3−δ/Sm0.2Ce0.8O1.9 Composite Material for Intermediate Temperature-Operating Solid Oxide Fuel Cell

Abstract

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 SmxSr1−x(Co,Fe,Ni)O3−δ/Sm0.2Ce0.8O1.9 on the Sm0.2Ce0.8O1.9 electrolyte and the possible use of an optimized composite material for the IT-SOFC system. The electrochemical and thermal properties of SmxSr1−x(Co,Fe,Ni)O3−δ and its composite material with the Sm0.2Ce0.8O1.9 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. Sm0.5Sr0.5CoO3−δ and the Sm0.5Sr0.5CoO3−δ/Sm0.2Ce0.8O1.9(6:4) composite cathode showed a very low ASR of 0.87 Ωcm2 and 0.30 Ωcm2 at 600°C, respectively. The composite type cathode for the Sm0.5Sr0.5CoO3−δ material was more attractive due to its thermal expansion compatibility with neighboring cell components.