Synthesis and characterization of nanoparticulate films for intermediate temperature solid oxide fuel cells

Nanocrystalline strontium-doped lanthanum manganite (LSM) with a high specific surface area of 70 m2/g was synthesized via spray pyrolysis. The as prepared powder was characterized by ex-situ X-ray diffraction (XRD), in-situ high temperature X-ray diffraction (HTXRD), ex-situ nitrogen adsorption and high resolution scanning electron microscopy (HRSEM). LSM nanopowders with a mean particle size of 40 nm were dispersed in water-based media using ultrasonication. Nanocomposite LSM-GDC (gadolinium doped ceria) thin films were prepared by single step spin coating of co-stabilized LSM and GDC dispersions. The thickness of these thin films (≤ 1 μm) is more than 10 times lower than conventional cathode layers prepared by screen printing. The interfacial polarization resistances were 68, 118 and 220 mΩ cm2 at 850, 800 and 750 °C, respectively. The high performance is attributed to small grain size, high porosity and large specific surface area. This method offers a very cost effective approach for the preparation of electrochemically highly active porous thin films, particularly applicable for micro solid oxide fuel cells.