Effect of Sr substitution on the Electrochemical Properties of Layered SmBa1-xSrxCo2O5+δ Perovskite Oxides for Intermediate-Temperature Solid Oxide Fuel Cells

Abstract

Cation ordered perovskites have been recognized as advanced cathode materials for intermediate-temperature solid oxide fuel cells (IT-SOFCs). This study focuses on the effects of Sr substitution on crystal characteristics, electrical properties, and electrochemical performance of SmBa1-xSrxCo2O5+δ (x = 0, 0.25, 0.5, 0.75, and 1.0) as an IT-SOFC cathode material. The electrical conductivity increases with increasing Sr content due to the increased interstitial oxygen and electronic holes. The ASRs of SmBa1-xSrxCo2O5+δ decrease with Sr content up to x = 0.75 and increase suddenly for x = 1, with the lowest ASR of 0.138 Ωcm2 at 600o C for x = 0.75. A Ni-GDC anode-supported cell is fabricated to evaluate the electrochemical performance of SmBa1-xSrxCo2O5+δ cathode material. The maximum power density is 1.039 Wcm−2 for x = 0.75 explaining faster oxygen diffusion compared with the other samples. These results indicate that SmBa1-xSrxCo2O5+δ is optimized at x = 0.75 in terms of the performance for IT-SOFCs.