Cobalt-free quintuple perovskite Sm1.875Ba3.125Fe5O15−δ as a novel cathode for intermediate temperature solid oxide fuel cells

Abstract

A novel cobalt-free quintuple perovskite Sm1.875Ba3.125Fe5O15−δ (SBF) oxide is synthesized and evaluated as cathode for IT-SOFCs. The chemical compatibility, electrical conductivity, thermal expansion coefficient and electrochemical performance are investigated. The SBF exhibits a good chemical compatibility with the La0.9Sr0.1Ga0.8Mg0.2O3−δ (LSGM) electrolyte at 1000°C for 5h. Its electrical conductivity is 9.2–11.8Scm−1 over the temperature range of 600–800°C. The average TEC of SBF is 17.2×10−6K−1 between 30°C and 1000°C. The area specific resistances of the SBF cathode on LSGM are 0.075Ωcm2 and 0.117Ωcm2 at 800°C and 750°C, respectively. Maximum power density is as high as 417mWcm−2 at 800°C based on a 300μm thick LSGM electrolyte. Preliminary results imply that SBF is an excellent oxygen reduction electrode candidate for IT-SOFCs.