A5032304759- Electronic and Structural Properties of Oxides
- Advancements in Solid Oxide Fuel Cells
- Magnetic and transport properties of perovskites and related materials
- Ferroelectric and Piezoelectric Materials
- Metal Extraction and Bioleaching
- Electrochemical Analysis and Applications
- Gas Sensing Nanomaterials and Sensors
- ZnO doping and properties
- Advanced Memory and Neural Computing
- Advanced X-ray Imaging Techniques
- Advanced ceramic materials synthesis
- Transition Metal Oxide Nanomaterials
- Advanced Battery Materials and Technologies
- Metal and Thin Film Mechanics
- Supercapacitor Materials and Fabrication
- Electrocatalysts for Energy Conversion
- Fuel Cells and Related Materials
- Nuclear Physics and Applications
- Catalysis and Oxidation Reactions
- Analytical Chemistry and Sensors
- Semiconductor materials and devices
- Crystallography and Radiation Phenomena
- Religious, Philosophical, and Educational Studies
- Magnetic Properties of Alloys
- Advanced Condensed Matter Physics
TU Wien
2011-2021
Austrian Economics Center
2015
Swiss Federal Laboratories for Materials Science and Technology
2012
Kaunas University of Technology
2009-2012
In this study, the contribution of grain boundaries to oxygen reduction and diffusion kinetics La0.8Sr0.2MnO3 (LSM) thin films is investigated. Polycrystalline LSM with columnar grains different sizes as well epitaxial were prepared by pulsed laser deposition. (18)O tracer exchange experiments performed at temperatures from 570 °C 810 subsequently analyzed secondary ion mass spectrometry (SIMS). The isotope concentration depth profiles polycrystalline clearly indicate contributions surface...
Revealing whether dislocations accelerate oxygen ion transport is important for providing abilities in tuning the ionic conductivity of ceramic materials. In this study, we report how affect diffusion Sr-doped LaMnO3 (LSM), a model perovskite oxide that serves energy conversion technologies. LSM epitaxial thin films with thicknesses ranging from 10 nm to more than 100 were prepared by pulsed laser deposition on single-crystal LaAlO3 and SrTiO3 substrates. The lattice mismatch between film...
An improved electrode geometry is proposed to study thin ion conducting films by impedance spectroscopy. It shown that long, thin, and closely spaced electrodes arranged interdigitally allow a separation of grain boundary effects also in very films. This be successful for yttria stabilized zirconia (YSZ) layers thinner than 20 nm. In series experiments it demonstrated the extracted parameters correspond YSZ bulk resistances or substrate capacitances. Results show our produced pulsed-laser...
The different properties of acceptor-doped (hard) and donor-doped (soft) lead zirconate titanate (PZT) ceramics are often attributed to amounts oxygen vacancies introduced by the dopant. Acceptor doping is believed cause high vacancy concentrations, while donors expected strongly suppress their amount. In this study, La3+ donor-doped, Fe3+ La3+/Fe3+-co-doped PZT samples were investigated tracer exchange electrochemical impedance spectroscopy in order analyse effect on concentrations....
Across-plane conductivity measurements on ion conducting thin films of a few ten nanometers thickness are challenging due to frequently occurring short-circuits through pinholes in the layer. In this contribution, method is proposed which allowed across-plane yttria stabilized zirconia (YSZ) layers with thicknesses as low 20 nm. YSZ were prepared onto silicon substrates native silica interlayer and was measured circular microelectrodes by impedance spectroscopy. The exhibits strongly...
Isotope exchange depth profiling and electrochemical impedance spectroscopy are usually regarded as complementary tools for measuring the surface oxygen activity of mixed conducting oxides, example used in solid oxide fuel cell (SOFC) electrodes. Only very few studies compared electrical (k(q)) tracer (k*) coefficients solid-gas interfaces measured under identical conditions. The 1:1 correlation between k(q) k* often made is thus more an assumption than experimentally verified. In this study...
Abstract Composites of ion and electron conducting phases allow for interfacial storage a neutral component via space charge effects. The present contribution considers the rate transport‐controlled incorporation excorporation in such artificial mixed conductors. upper limit relaxation time is determined by job‐sharing diffusion which analyzed greater detail. In general cases bulk assist migration processes (dual phase transport). For more complex morphological situations, considerations are...
The oxygen stoichiometry of mixed conducting oxides depends on the chemical potential and thus partial pressure in gas phase. Also voltages may change local amount to which such changes take place is quantified by capacitance sample. Impedance spectroscopy can be used probe this capacitance. measurements different ((La,Sr)FeO 3- d = LSF, Sr(Ti,Fe)O STF, Pb(Zr,Ti)O 3 PZT) are presented, demonstrate how affect impedance spectra types electrochemical cells. A quantitative analysis based...
Many efforts are being made to tune perovskite thin film cathodes toward improving their oxygen reduction kinetics and thereby overall solid oxide fuel cell performance. One approach is enhance diffusion via introduction of larger concentrations grain boundaries during growth. While such boundary engineering has been shown ionic transport surface reaction in some cases, little attention paid on its corresponding influence electronic conductivity. To provide insights into the role...
We employed operando anomalous surface X-ray diffraction to investigate the buried interface between cathode and electrolyte of a model solid oxide fuel cell with atomic resolution. The was studied under different oxygen pressures at elevated temperatures polarizations by external potential control. Making use effects Y Zr K-edges allowed us resolve interfacial structure chemical composition (100)-oriented, 9.5 mol % yttria-stabilized zirconia (YSZ) single crystal below La0.6Sr0.4CoO3-δ...
Oxygen ion conduction in Nd 3+ ‐doped Pb(Zr x Ti 1− )O 3 ( PZT ) was investigated by impedance spectroscopy and 18 O‐tracer diffusion with subsequent secondary mass spectrometry SIMS analysis. Ion blocking electrodes lead to a second relaxation feature spectra at temperatures above 600°C. This allowed analysis of ionic electronic partial conductivities. Between 600°C 700°C those are the same order magnitude (10 −5 –10 −4 S/cm) though very differently activated (2.4 eV vs. 1.2 for ions...
Abstract The impact of cathodic bias on oxygen transport in La 0.8 Sr 0.2 MnO 3 (LSM) thin films was investigated. Columnar‐grown LSM with different microstructures were deposited by pulsed laser deposition. 18 O tracer experiments performed film microelectrodes an applied −300 or −450 mV, and the subsequently analyzed time‐of‐flight secondary ion mass spectrometry. concentration cathodically polarized strongly increased relative to that thermally annealed (without bias). Most remarkable,...
Yttria stabilized zirconia (YSZ) thin films of 20 to 90 nm thickness were prepared by pulsed laser deposition (PLD) on silicon substrates with a native silica layer. The high dc resistance the interlayer causes strongly frequency dependent current lines between two stripe electrodes YSZ This allows determination in- and across-plane conductivity film from single impedance spectrum. part spectra corresponds an measurement geometry while low is governed in-plane flow. It shown that measured...
The effect of an applied overpotential on oxygen isotope incorporation and diffusion in oxide thin film electrodes is investigated by a novel experimental approach. A special electrode geometry leads to in-plane electron flow, perpendicular ion flow well-defined laterally varying driving force. This design allows one obtain series tracer depth profiles induced range overpotentials the same film. approach was La0.8Sr0.2MnO3 (LSM) films deposited pulsed laser deposition (PLD) yttria stabilized...
We report on platinum oxide formation during electrochemical anodic polarization of a film yttria-stabilized zirconia (YSZ) under oxygen potential control. The drives through the YSZ electrolyte towards nominally 175 nm thin Pt film, which we found to locally delaminate from substrate by forming nano-scale blisters. High resolution scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDX) mapping focused-ion beam (FIB)-prepared cross-sections single bubbles few micrometers...
Thermally and electrochemically driven
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Much attention has recently been focused on the oxygen reduction via Sr-doped lanthanum manganite grain boundaries (GBs) since transport, as well surface exchange is approximately 1000x faster at GBs than for LSM bulk. With this in mind, there a strong incentive to tailor properties of thin films by GB engineering. To date, effect el. conductivity not studied such engineered films. In study, changing microstructure, strain, were found heavily influence charge transport. More specifically,...