Deposition and Electrical and Structural Properties of La0.6Sr0.4CoO3 Thin Films for Application in High-Temperature Electrochemical Cells

Abstract

Low-temperature deposition of electroceramic thin films allows the construction of new devices and their integration with existing large-scale fabrication methods. Developing a suitable low-cost deposition method is important to further advance the development of microdevices. In this work, we deposited a 1-lm-thick La 0.6 Sr 0.4 CoO 3Àd (LSC) perovskite with high electrical conductivity on sapphire substrates at 400°C and analyzed its electrical, morphological and structural properties as a function of temperature in the range of 400-1100°C. The results show that spray pyrolysis can be used to deposit highquality reproducible layers with the desired chemical and phase composition. Upon heating to around 600°C, the residual CO and C=O species are removed, and the deposited layers crystallize and become conducting. The dependence of electrical conductivity versus processing temperature has a complex character-the maximum conductivity is found for layers processed at 800°C. An analytical model of stress distribution was used to predict stress to which the bi-layer material would be exposed to while being cooled down from the annealing temperature to room temperature. The high electronic conductivity and high-quality microstructure of the LSC layers, which can be adjusted with the appropriate heat treatment procedure, make them suitable for applications in electrochemical devices applied in integrated energy modules, including electrodes or contacts.

Tuning Electrochemical Performance by Microstructural Optimization of the Nanocrystalline Functional Oxygen Electrode Layer for Solid Oxide Cells

“…600 °C, as was previously studied for the layers on sapphire substrates. 19 The LSC peaks are marked according to PDF #00-36-1393, corresponding to the rhombohedral structure, though the cubic structure also fits well, in agreement with the literature. 25 The main LSC peaks (indexed as 110, 104) overlap with the main CGO peak (PDF #00-50-0201, (200) peak approx.…”

“…This effect was presented in our earlier publication examining the properties of the LSC layer deposited from different amounts of precursor solution. 19 On the other hand, above 1 μm thickness, the droplets overlap and start making clear differences in the thickness of the layer visible in the crosssectional images, giving the impression of a wavy surface. The 50 nm-thick layer is not a continuous layer, and the LSCF is partially in direct contact with the electrolyte.…”

Improvement of Oxygen Electrode Performance of Intermediate Temperature Solid Oxide Cells by Spray Pyrolysis Deposited Active Layers

“…For the perovskite‐based materials, the average grain size was 64 (±17) nm and for PrO x it was slightly higher 78 (±21) nm. In previous research [ 31 ] of La 0.6 Sr 0.4 CoO 3 layers deposited on the sapphire substrate, we studied the influence of annealing temperature on the microstructure of layers in the temperature range of 390–1100 °C. The morphology of layers annealed at 600 and 700 °C was very similar.…”

“…Oxygen electrode functional layers were produced using the spray pyrolysis technique described in detail in the Experimental Section and our recent works. [30,31] For microstructural characterization, layers were deposited on an amorphous SiO 2 substrate (a-SiO 2 ). The amorphous substrate was chosen for crystallographic measurements since no background peaks are present in the spectra.…”

Visualizing local fast ionic conduction pathways in nanocrystalline lanthanum manganite by isotope exchange-atom probe tomography

“…A thin barrier layer of Ce 0.8 Sm 0.2 O 1.9 (SDC) was deposited before the LSM film in order to avoid cationic intermixing at the interface. 40 Both layers were deposited at 700 °C, under an oxygen pressure of 2.6 × 10 −2 mbar, target–substrate distance of 95 mm, laser fluency ≈1.2 J cm −2 and 5 Hz of laser frequency. The thickness of LSM and SDC layers deposited was ≈45 nm and ≈35 nm, respectively, as measured by spectroscopy ellipsometry (UVISEL, Horiba scientific).…”