Preparation and Characterization of (La0.8Sr0.2)0.95MnO3-δ (LSM) Thin Films and LSM/LSCF Interface for Solid Oxide Fuel Cells

Uniform, dense, and conformal coatings of (La,Sr)MnO3-delta (LSM) have been successfully deposited on a silicon wafer and a dense (La,Sr)(Co,Fe)O3-delta (LSCF) substrate using a stable LSM sol consisting of metal acetate and nitrate precursors dissolved in a mixed organic solvent of 2-methoxyethanol and acetic acid with enhanced wettability. The processing conditions are optimized for precise control of composition, morphology, microstructure, and thickness of the LSM films to examine the microstructure and chemical stability of an LSM film as a catalytic coating for an LSCF cathode. The thicknesses of the LSM films are controlled within the range of 5-60 nm by spin-coating of LSM sol with different concentrations. The LSM films grow epitaxially on the LSCF substrate grains after annealing at 800 degrees C for 1 h due to their structural similarity. The LSM coatings show good stability on LSCF substrates and may suppress strontium oxide segregation on LSCF surface during annealing at 850 degrees C for 900 h, implying that LSM-coated LSCF surfaces have better structural and chemical stability under typical fuel cell operating conditions.