Chromium poisoning effect on strontium-doped samarium manganite for solid oxide fuel cell

Strontium-doped samarium manganite is a potential cathode for solid oxide fuel cells (SOFCs) with remarkable high oxygen reduction reaction activity. Here we investigated chromium poisoning effect on Sm0.5Sr0.5MnO3 cathode of SOFCs for the first time. The Cr caused cathode degradation is studied under current density of 200 mA cm−2 and open circuit potential (OCP) at 750 °C. After polarized in the presence of the Crofer22 APU at 750 °C for 1200 min, the polarization resistance decreases from 3.25 Ω cm2 to 2.25 Ω cm2, then increases to a stable value of 2.75 Ω cm2. The degradation rate of SSM is lower than that of LSM cathode in the same experimental environment. At OCP, the polarization resistance increases to 7.00 Ω cm2 and reaches a stable level. SEM and EDX shows the depositions on the Sm0.5Sr0.5MnO3 boundary after applying current for 1200 min, and on the SSM surface after aging at OCP for 200 h. The Cr depositions are mainly comprised of SrCrO4 formed by the nucleation reaction. The results show that SSM is a poisoning tolerant cathode and good replacement for the LSM in IT-SOFCs due to the better electrochemical performance and the relatively stable characteristics after Cr poisoning.