Spray Pyrolysis Assisted Synthesis of Doped Barium Ferrite and Lanthanum Barium Ferrite-based SOFC Cathodes with Tailored Particulate Size and Morphology

摘要

Doped barium ferrite [Ba_(1-x)Sr_xCo_(1-y)Fe_yO_(3-δ) (BSCF) 0 ＜ x ≤ 0.5, y = 0.2 and 0.8] and lanthanum barium ferrite [Ba_(1-x-m)La_xSr_m Co_(1-y)Fe_yO_(3-δ)(LBSCF); (x + m) = 0.75, m = 0.5, y = 0.2 and 0.8] based SOFC cathode with tailored particulate size and morphology are synthesized by spray pyrolysis. Near-net to spherical shape nano to micro particulates (100 nm - 5 μm) with in-built meso and micro porosity are prepared either by direct pyrolysis or by in-situ growth of nanoparticulates inside the reactor through homomolecular nucleation. Symmetric cells with optimized cathode particulate size, morphology and electrical conductivity reduce interfacial polarizations down to 0.048 Ω.cm~2 and 0.014 Ω.cm~2 at 700°C and consequently enhance the current densities to 1.8 Acm~(-2) and 2.2 Acm~(-2) (0.7 V, 700°C) with hydrogen and air for BSCF and LBSCF respectively. Microstructures of such cathodes are correlated with augmented cell performances for short and long term operation.