Strain-induced structure and oxygen transport interactions in epitaxial La0.6Sr0.4CoO3−δ thin films

Abstract

The possibility to control oxygen transport in one of the most promising solid oxide fuel cell cathode materials, La 0.6 Sr 0.4 CoO 3−δ , by controlling lattice strain raises questions regarding the contribution of atomic scale effects. Here, high-resolution transmission electron microscopy revealed the different atomic structures in La 0.6 Sr 0.4 CoO 3−δ thin films grown under tensile and compressive strain conditions. The atomic structure of the tensile-strained film indicated significant local concentration of the oxygen vacancies, with the average value of the oxygen non-stoichiometry being much larger than for the compressive-strained film. In addition to the vacancy concentration differences that are measured by isotope exchange depth profiling, significant vacancy ordering was found in tensile-strained films. This understanding might be useful for tuning the atomic structure of La 0.6 Sr 0.4 CoO 3−δ thin films to optimize cathode performance.

Performance modulation through selective, homogenous surface doping of lanthanum strontium ferrite electrodes revealed by in situ PLD impedance measurements

“…The exact mechanism how Pt increases the surface vacancy concentration is still unknown, but it seems plausible that the incorporation of larger Pt 4+ ions on the Fe 3+ lattice site leads to a slight enlargement of the unit cell, which decreases the formation enthalpy of oxygen vacancies. 42,99,100 This is also in accordance with XRD measurement, where an increase of the unit cell of Pt doped LSF compared to pure LSF was observed.…”

Inhibiting in situ phase transition in Ruddlesden-Popper perovskite via tailoring bond hybridization and its application in oxygen permeation

“…The state-of-the-art materials for MIEC membranes are perovskite oxides (ABO 3 ) containing La, Sr, and/or Ba in the A-site and Fe, Co, Cu, or Nb in the B-site to obtain high oxygen diffusion and permeation fluxes. [26][27][28][29][30][31][32][33][34][35] However, most of these perovskite membranes cannot tolerate long-term exposure to CO 2 as a carbonate layer is formed that is oxygen impermeable. As a special layer-structured perovskite material, Ruddlesden-Popper (RP; A n+1 B n O 3n+1 ) materials with the K 2 NiF 4 structure represent an attractive alternative to these perovskite oxides because of their excellent CO 2 resistance and good oxygen conductivity.…”

Negatively Charged In-Plane and Out-Of-Plane Domain Walls with Oxygen-Vacancy Agglomerations in a Ca-Doped Bismuth-Ferrite Thin Film

“…During the deposition, the substrate was maintained at a temperature of 700 °C with an oxygen environment of 100 mTorr. Cross-sectional samples for the TEM investigations were prepared using a Helios Nanolab FIB-SEM by a standard focused ion beam protocol. − …”