Crystal structure, thermal expansion and long-term behaviors of SmBaCoO_5+δ as cathode for intermediate-temperature solid oxide fuel cells

¹ Department of Mechanical Engineering, Sekolah Tinggi Teknologi Nasional (STTNAS), Yogyakarta 55281, Indonesia
² Department of Materials Science & Engineering, National Dong Hwa University, Shou-Feng, Hualien 97401, Taiwan

^* Corresponding author: subardi@sttnas.ac.id

Abstract

SmBaCo₂O_5+δ (SBC) was studied as cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The crystal structure, thermal expansion behavior, and electrochemical performance with long-term operation of SBC were characterized. An orthorhombic layered perovskite structure was observed in SBC cathode by a GSAS program for refinement. The average thermal expansion coefficient (TEC) is 21.6 x 10^-6K^-1 in the temperature range of 100^oC-800^oC. For long-term testing, the polarization resistance of SBC cathode increases gradually from 25.77 Ω cm² for 2 h to 38.77 Ω cm² for 96 h at 600^°C, and an increasing-rate for polarization resistance is around 13,8% h^-1. Based on the electrochemical properties, SBC cathode with mixed ionic and electronic conductor (MIEC) behavior is a potential cathode for intermediate temperature solid oxide fuel cells based on a SDC electrolyte.