Dataset Information

Formation and Detection of High-Pressure Oxygen in Closed Pores of La_0.6Sr_0.4CoO_3-δ Solid Oxide Electrolysis Anodes.

ABSTRACT: The chemical capacitance of La_0.6Sr_0.4CoO_3-δ (LSC) thin film microelectrodes with different microstructures was investigated upon varying anodic DC voltages. Dense and porous electrodes (open porosity) were prepared by using different parameters during pulsed laser deposition (PLD). Furthermore, electrodes with closed porosity were fabricated by depositing a dense capping layer on a porous film. Electrochemical impedance spectroscopy (EIS) was performed in synthetic air at 460 and 608 °C with anodic DC voltages up to 440 mV. Chemical capacitance values of the electrodes were derived from the obtained spectra. While the chemical capacitance of dense and porous electrodes decreased as expected with increasing anodic overpotential, electrodes with closed pores exhibited very unusual peaks with extremely high values of >8000 F/cm³ at overpotentials of >100 mV. We demonstrate that this huge capacitance increase agrees very well with calculated chemical capacitances deduced from a real gas equation. Hence, we conclude that the formation of highly pressurized oxygen (up to gas pressures of ∼10⁴ bar) in closed pores is responsible for this strong capacitive effect at anodic overpotentials. Such measurements can thus detect and quantify the buildup of high internal gas pressures in closed pores at the anode side of solid oxide electrolysis cells.

SUBMITTER: Krammer M

PROVIDER: S-EPMC9326814 | biostudies-literature | 2022 Jul

REPOSITORIES: biostudies-literature

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Publications

Formation and Detection of High-Pressure Oxygen in Closed Pores of La0.6Sr0.4CoO3-δ Solid Oxide Electrolysis Anodes.

Krammer Martin M Schmid Alexander A Siebenhofer Matthäus M Bumberger Andreas Ewald AE Herzig Christopher C Limbeck Andreas A Kubicek Markus M Fleig Juergen J

ACS applied energy materials 20220623 7

The chemical capacitance of La0.6Sr0.4CoO3-δ (LSC) thin film microelectrodes with different microstructures was investigated upon varying anodic DC voltages. Dense and porous electrodes (open porosity) were prepared by using different parameters during pulsed laser deposition (PLD). Furthermore, electrodes with closed porosity were fabricated by depositing a dense capping layer on a porous film. Electrochemical impedance spectroscopy (EIS) was performed in synthe ...[more]

PMID: 35909806

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Project description:The further development of solid oxide fuel and electrolysis cells (SOFC/SOEC) strongly relies on research activities dealing with electrode materials. Recent studies showed that under operating conditions many perovskite-type oxide electrodes are prone to changes of their surface composition, leading to severe changes of their electrochemical performance. This results in a large scatter of data in literature and complicates comparison of materials. Moreover, little information is available on the potentially excellent properties of surfaces immediately after preparation, that is, before any degradation by exposure to other gas compositions or temperature changes. Here, we introduce in situ impedance spectroscopy during pulsed laser deposition (IPLD) as a new method for electrochemical analysis of mixed ionic and electronic conducting (MIEC) thin films during growth. First, this approach can truly reveal the properties of as-prepared MIEC electrode materials, since it avoids any alterations of their surface between preparation and investigation. Second, the measurements during growth give information on the thickness dependence of film properties. This technique is applied to La0.6Sr0.4CoO3-δ (LSC), one of the most promising SOFC/SOEC oxygen electrode material. From the earliest stages of LSC film deposition on yttria-stabilized zirconia (YSZ) to a fully grown thin film of 100 nm thickness, data are gained on the oxygen exchange kinetics and the defect chemistry of LSC. A remarkable reproducibility is found in repeated film growth experiments, not only for the bulk related chemical capacitance but also for the surface related polarization resistance (±10%). Polarization resistances of as-prepared LSC films are extraordinarily low (2.0 Ω cm2 in 40 μbar O2 at 600 °C). LSC films on YSZ and on La0.95Sr0.05Ga0.95Mg0.05O3-δ (LSGM) single crystals exhibit significantly different electrochemical properties, possibly associated with the tensile strain of LSC on LSGM.

Dataset Information

Formation and Detection of High-Pressure Oxygen in Closed Pores of La_0.6Sr_0.4CoO_3-δ Solid Oxide Electrolysis Anodes.

Publications

Formation and Detection of High-Pressure Oxygen in Closed Pores of La<sub>0.6</sub>Sr<sub>0.4</sub>CoO<sub>3-δ</sub> Solid Oxide Electrolysis Anodes.

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