Abstracts Book - IMRC 2018

• SC1-P018
SYNTHESIS, STRUCTURAL, MORPHOLOGICAL AND TRANSPORT
PROPERTIES OF Ce1-x SmXO2-δ (SDC) AND La0.6Sr0.4Co0.2Fe0.8O3-δ
(LSCF) THIN FILMS OBTAINED BY ULTRASONIC SPRAY PYROLYSIS
Ruben Martinez Bautista 1 , José Alvaro Chávez Carvayar 1
1 Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México,
Mexico.
Solid oxide fuel cells (SOFCs) are clean and efficient devices for chemical to
electrical energy conversion. During the last decades, in addition to stabilized
zirconia, ceria based electrolytes have been investigated as solid electrolytes for
intermediate temperature SOFCs (IT–SOFCs) due to their high ionic conductivity.
For synthesis, the ultrasonic spray deposition (USD) leads to smaller and more
homogeneous droplet size than electrostatic or pressurized spray (EPS)
methods, which allows the deposition of homogeneous thin films with excellent
physical properties that may be used as solid electrolytes for SOFCs. In this work,
the synthesis and the structural, morphological and electrical characterization
of Ce1-xSmxO2-δ solid solution, with x = 0, 0.10, 0.15, 0.20, 0.25 and 0.30 mol, are
reported. Nanocrystalline, homogeneous, and adherent samarium doped
cerium oxide thin films were deposited onto fused-silica by a simple and cost
effective ultrasonic spray pyrolysis system, at a low substrate temperature of
450°C and further annealing treatment at 500°C. Products were characterized
by X-ray diffraction, scanning electron microscopy, atomic force microscopy, and
impedance spectroscopy. For all the samples, X-ray diffraction patterns
indicated the formation of single phase and well crystalline thin films, with cubic
fluorite type structure. Scanning Electron Microscopy analyses showed
homogeneous surfaces for all the samples; crystallite size was found to be in the
range of 14–35 nm. From Atomic Force Microscopy, surface roughness in the
range of 20 to 95 nm was measured and the formation of smooth films with an
average grain size of 40 nm was observed. At 450°C, high oxygen ion
conductivity of 1.71 × 10 -1 Scm -1 was determined by impedance spectroscopy for
the best sample in the solid solution, with an activation energy of 0.93 eV.
Results suggest that these films show a potential application as electrolytes in
intermediate temperature solid oxide fuel cells (IT-SOFC).