Intercalation of Thin-Film Gd-Doped Ceria Barrier Layers in Electrolyte-Supported Solid Oxide Cells: Physicochemical Aspects
journal contributionposted on 28.07.2021, 12:04 authored by Matthias Riegraf, Feng Han, Noriko Sata, Rémi Costa
To minimize alteration of the La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF)/Gd0.2Ce0.8O2−δ(CGO20)/Y0.06Zr0.94O2−δ(3YSZ) interface via strontium zirconate formation in solid oxide cells, electron beam physical vapor deposition was employed to manufacture dense, thin gadolinium-doped ceria (CGO) interlayers. CGO layers with thicknesses of 0.15, 0.3, and 0.5 μm were integrated in state-of-the-art 5 × 5 cm2-large electrolyte-supported cells, and their performance characteristics and degradation behavior were investigated. Electrochemical impedance spectroscopy measurements are correlated with a postmortem scanning electron microscopy/energy-dispersive X-ray spectroscopy analysis to show that 0.15 μm-thick layers lead to the formation of a continuous Sr-containing secondary phase at the CGO/YSZ interface, likely related to the formation of a SrO–ZrO2 phase. Major performance losses were confirmed by an increase in both Ohmic and polarization resistance with an increase in the frequency region ∼103 Hz. Cells with 0.3 μm- and 0.5 μm-thick CGO layers showed similar high performance and low degradation rates over a testing period of ∼800 h. The YSZ/CGO interface of the cells with a 0.3 μm-thick CGO layer showed the formation of a discontinuous Sr-containing secondary phase; however, performance losses were still successfully prevented. Furthermore, it is observed that 0.5 μm-thick CGO layers were sufficient to suppress the formation of the Sr-containing secondary phase.
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Major performance lossesPhysicochemical AspectsCGO layers0.5 μ m-thick CGO layersElectrochemical impedance spectrosc...0.3 μ m-thick CGO layerelectron beamYSZdegradation ratesThin-Film Gd-Doped Ceria Barrier Layerselectrolyte-supported cellsperformance lossesSr-containinginterfacegadolinium-doped ceriatesting periodperformance characteristicsLSCFvapor deposition0.5 μ moxide cellspolarization resistancedegradation behavior0.15 μ m-thick layersOxide Cellsphasestrontium zirconate formation0.3 μ m