Cobalt-free La0.5Sr0.5Fe0.9Mo0.1O3-δ electrode for symmetrical SOFC running on H2 and CO fuels

Cobalt-free perovskite La0.5Sr0.5Fe0.9Mo0.1O3-delta (LSFMo) was evaluated as the electrode of symmetrical SOFC (S-SOFC) using H-2 and CO as fuels. XRD results demonstrate that the LSFMo electrode is redox stable at a temperature below 800 degrees C. Furthermore, the chemical compatibility of LSFMo electrode with both Sm0.2Ce0.8O1.95 (SDC) and La0.5Sr0.5Fe0.9Mo0.1O3-delta (LSGM) electrolytes was assessed. The thermal expansion coefficients (TECs) of the LSFMo at 30-850 degrees C are 13.4 x 10(-6) K-1 in air and 15.1 x 10(-6) K-1 in 5% H-2/Ar. However, for the pre-reduced LSFMo, the TEC in 5% H-2/Ar decreases to 11.8 x 10(-6) K-1. Using LSFMo as symmetrical electrode of S-SOFCs, the maximum power densities (P-max) of 562 mW cm(-2) in dry H-2 and 474 mW cm(-2) in dry CO at 750 degrees C are attained based on 300 mu m thick SDC electrolyte, while based on the LSGM electrolyte with same thickness, the P-max attain 508 mW cm(-2) in dry H-2 and 379 mW cm(-2) in dry CO. For the LSGM supported S-SOFC, the total polarization resistances (R-p) attain 0.460 Omega cm(2) in dry H-2 and 1.099 Omega cm(2) in dry CO at 750 degrees C. Additionally, the S-SOFCs with LSFMo electrode exhibit good power cycling stability, long-term stability and multiple redox and thermal cycling stability. Above results indicate that the LSFMo material is a very potential symmetrical electrode for S-SOFCs. (C) 2019 Elsevier Ltd. All rights reserved.