Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Dynamic Impedance Spectroscopy of Nickel Hexacyanoferrate Thin Films.

ABSTRACT: Dynamic multi-frequency analysis (DMFA) is capable of acquiring high-quality frequency response of electrochemical systems under non-stationary conditions in a broad range of frequencies. In this work, we used DMFA to study the kinetics of (de-)intercalation of univalent cations (Na+ and K+) in thin films of nickel hexacyanoferrate (NiHCF) during cyclic voltammetry. For this system, the classic stationary electrochemical impedance spectroscopy fails due to the instability of the oxidized form of NiHCF. We are showing that such spectra can be fitted with a physical model described by a simple two-step intercalation mechanism: an adsorption step followed by an insertion step. The extracted kinetic parameters are depending on the state of charge as well on the nature of the inserted cation.

SUBMITTER: Erinmwingbovo C

PROVIDER: S-EPMC6919401 | biostudies-literature | 2019 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Dynamic Impedance Spectroscopy of Nickel Hexacyanoferrate Thin Films.

Erinmwingbovo Collins C Koster Dominique D Brogioli Doriano D La Mantia Fabio F

ChemElectroChem 20190820 21

Dynamic multi-frequency analysis (DMFA) is capable of acquiring high-quality frequency response of electrochemical systems under non-stationary conditions in a broad range of frequencies. In this work, we used DMFA to study the kinetics of (de-)intercalation of univalent cations (Na+ and K+) in thin films of nickel hexacyanoferrate (NiHCF) during cyclic voltammetry. For this system, the classic stationary electrochemical impedance spectroscopy fails due to the instability o ...[more]

PMID: 31894198

Similar Datasets

Dynamic phase transitions in freestanding polymer thin films.

Project description:After more than two decades of study, many fundamental questions remain unanswered about the dynamics of glass-forming materials confined to thin films. Experiments and simulations indicate that free interfaces enhance dynamics over length scales larger than molecular sizes, and this effect strengthens at lower temperatures. The nature of the influence of interfaces, however, remains a point of significant debate. In this work, we explore the properties of the nonequilibrium phase transition in dynamics that occurs in trajectory space between high- and low-mobility basins in a set of model polymer freestanding films. In thick films, the film-averaged mobility transition is broader than the bulk mobility transition, while in thin films it is a variant of the bulk result shifted toward a higher bias. Plotting this transition's local coexistence points against the distance from the films' surface shows thick films have surface and film-center transitions, while thin films practically have a single transition throughout the film. These observations are reminiscent of thermodynamic capillary condensation of a vapor-liquid phase between parallel plates, suggesting they constitute a demonstration of such an effect in a trajectory phase transition in the dynamics of a structural glass former. Moreover, this transition bears similarities to several experiments exhibiting anomalous behavior in the glass transition upon reducing film thickness below a material-dependent onset, including the broadening of the glass transition and the homogenization of surface and bulk glass transition temperatures.

| S-EPMC7568329 | biostudies-literature

Ion-Conducting Flexible Thin Films of Composites from Poly(ethylene oxide) and Nematic Liquid Crystals E8-Characterization by Impedance and Dielectric Relaxation Spectroscopy.

Project description:Complex electrical impedance and dielectric spectroscopy were applied to study the dielectric relaxations and their thermal behavior in ion-conducting composites/complexes from polymer poly(ethylene oxide) (PEO) and E8 nematic liquid crystals (LCs), at the compositional ratio PEO:E8 = 70:30 wt%. Flexible thin films of PEO/E8 with a thickness of 150 μm were inspected, as well as such films from Na+ ion-conducting electrolyte PEO/E8/NaIO4 with the same PEO:E8 compositional ratio, but additionally containing 10 wt.% from the salt sodium metaperiodate (NaIO4) as a dopant of Na+ ions. The molecular dynamics, namely the dielectric relaxation of PEO/E8 and PEO/E8/NaIO4, were characterized through analyses of complex impedance and dielectric spectra measured in the frequency range of 1 Hz-1 MHz, under variation of temperature from below to above the glass-transition temperature of these composites. The relaxation and polarization of dipole formations in PEO/E8 and PEO/E8/NaIO4 were evidenced and compared in terms of both electrical impedance and dielectric response depending on temperature. The results obtained for molecular organization, molecular relaxation dynamics, and electric polarization in the studied ion-conducting polymer/LC composites/complexes can be helpful in the optimization of their structure and performance, and are attractive for applications in flexible organic electronics, energy storage devices, and mechatronics.

| S-EPMC8704298 | biostudies-literature

Combination of Solid-State and Electrochemical Impedance Spectroscopy To Explore Effects of Porosity in Sol-Gel-Derived BaTiO3 Thin Films.

Project description:BaTiO3 thin films were deposited onto polycrystalline Pt using a dip-coating technique, with annealing temperatures of 750-900 °C. To avoid film imperfections such as cracking or pinholes, key conditions, including aging periods, water content, and stirring speeds, were refined to produce a pinhole-free, uniform film with some porosity. Whereas those coated a single time short circuited during electrical characterization, this could be avoided in films produced by multiple coating cycles. The effective permittivity of a 600 nm BaTiO3 film was measured at 290 by fitting solid-state impedance data in the frequency range of 100 Hz to 1 MHz. Electrochemical impedance with an aqueous electrolyte allowed evaluation of the porosity, which remained fairly constant between 1 and 5 coating cycles. Using this method, it was possible to estimate the effective permittivity of the BaTiO3 itself as 374 and hence to evaluate the increase in the effective permittivity that could be achieved by minimizing porosity.

| S-EPMC6644393 | biostudies-literature

Profilometry of thin films on rough substrates by Raman spectroscopy.

Project description:Thin, light-absorbing films attenuate the Raman signal of underlying substrates. In this article, we exploit this phenomenon to develop a contactless thickness profiling method for thin films deposited on rough substrates. We demonstrate this technique by probing profiles of thin amorphous silicon stripes deposited on rough crystalline silicon surfaces, which is a structure exploited in high-efficiency silicon heterojunction solar cells. Our spatially-resolved Raman measurements enable the thickness mapping of amorphous silicon over the whole active area of test solar cells with very high precision; the thickness detection limit is well below 1?nm and the spatial resolution is down to 500?nm, limited only by the optical resolution. We also discuss the wider applicability of this technique for the characterization of thin layers prepared on Raman/photoluminescence-active substrates, as well as its use for single-layer counting in multilayer 2D materials such as graphene, MoS2 and WS2.

| S-EPMC5138622 | biostudies-literature

High-Performance Planar Thin Film Thermochromic Window via Dynamic Optical Impedance Matching.

Project description:Window coatings with dynamic solar transmittance represent an excellent opportunity to reduce building heating and cooling loads, which account for >40% of energy consumed by the built environment. In particular, inorganic vanadium dioxide-based thermochromic coatings offer long lifetimes (>30 years) and can be passively integrated into a window system without additional electronics or power requirements. However, their limited solar modulation depth and wide phase-change hysteresis have traditionally restricted their ability to adapt to changing weather conditions. Here, we derive an optical performance limit for thin film vanadium dioxide coatings, which we find to be far beyond the current literature. Furthermore, we experimentally demonstrate a solution-processed multilayer thin film coating that uses temperature-dependent optical impedance matching to approach the optical performance limit. The thin film coating demonstrated has a record solar transmittance modulation of 21.8% while maintaining a high level of visible transparency (?50%) and minimal hysteresis (?10 °C). This work represents a step-change in thin film thermochromic window coatings and, as a result, establishes planar thin film vanadium dioxide as the most viable morphology for high-performance thermochromic windows.

| S-EPMC7033656 | biostudies-literature

Local degradation pathways in lithium-rich manganese-nickel-cobalt-oxide epitaxial thin films.

Project description:The electrochemical performance and microstructure of positive electrodes are intimately linked. As such, developing batteries resistance to capacity and voltage fade requires understanding these underlying structure-properties relationships and their evolution with operation. Epitaxial films of a Li-rich manganese-nickel- cobalt oxide cathode material were deposited on (100) and (111) orientated SrRuO3/SrTiO3 substrates. Cyclic voltammetry and impedance spectroscopy tracked the response of these positive electrode materials, while the microstructure of the pristine and cycled films was characterized using transmission electron microscopy. Energy-dispersive X-ray spectroscopy identifies compositional fluctuations in as-deposited films. Phase transformations and dissolution were observed after electrochemical testing. There is a correlation between both local composition and substrate orientation (i.e., surface faceting) and what degradation pathways are active. Regions with comparatively higher concentrations of Ni and Co were more resistant to dissolution and unfavorable phase transformations than those with relatively more Mn. As such, a global composition metric may not be an accurate predictor of degradation and performance. Rather possessing the synthetic ability to engineer the chemical profile as well as characterizing it, pose a challenge and opportunity.

| S-EPMC7552892 | biostudies-literature

Morphological, Optical, and Electrical Properties of p-type Nickel Oxide Thin Films by Nonvacuum Deposition.

Project description:In this study, a p-type 2 at% lithium-doped nickel oxide (abbreviation L2NiO) solution was prepared using Ni(NO3)2·6H2O, and LiNO3·L2NiO thin films were deposited using an atomizer by spraying the L2NiO solution onto a glass substrate. The sprayed specimen was heated at a low temperature (140 °C) and annealed at different high temperatures and times. This method can reduce the evaporation ratio of the L2NiO solution, affording high-order nucleating points on the substrate. The L2NiO thin films were characterized by X-ray diffraction, scanning electron microscopy, UV-visible spectroscopy, and electrical properties. The figure of merit (FOM) for L2NiO thin films was calculated by Haacke's formula, and the maximum value was found to be 5.3 × 10-6 ?-1. FOM results revealed that the L2NiO thin films annealed at 600 °C for 3 h exhibited satisfactory optical and electrical characteristics for photoelectric device applications. Finally, a transparent heterojunction diode was successfully prepared using the L2NiO/indium tin oxide (ITO) structure. The current-voltage characteristics revealed that the transparent heterojunction diode exhibited rectifying properties, with a turn-on voltage of 1.04 V, a leakage current of 1.09 × 10-4 A/cm2 (at 1.1 V), and an ideality factor of n = 0.46.

| S-EPMC7221566 | biostudies-literature

Emergence of the Stoner-Wohlfarth astroid in thin films at dynamic regime.

Project description:The Stoner-Wohlfarth (SW) model is the simplest model that describes adequately the magnetization reversal of nanoscale systems that are small enough to contain single magnetic domains. However for larger sizes where multi-domain effects are present, e.g., in thin films, this simple macrospin approximation fails and the experimental critical curve, referred as SW astroid, is far from its predictions. Here we show that this discrepancy could vanish also in extended system. We present a detailed angular-dependent study of magnetization reversal dynamics of a thin film with well-defined uniaxial magnetic anisotropy, performed over 9 decades of applied field sweep rate (dH/dt). The angular-dependent properties display a gradual transition from domain wall pinning and motion-like behaviour to a nucleative single-particle one, as dH/dt increases. Remarkably, in the high dynamic regime, where nucleation of reversed domains is the dominant mechanism of the magnetization reversal (nucleative regime), the magnetic properties including the astroid become closer to the ones predicted by SW model. The results also show why the SW model can successfully describe other extended systems that present nucleative regime, even in quasi-static conditions.

| S-EPMC5647445 | biostudies-literature

NMR spectroscopy for thin films by magnetic resonance force microscopy.

Project description:Nuclear magnetic resonance (NMR) is a fundamental research tool that is widely used in many fields. Despite its powerful applications, unfortunately the low sensitivity of conventional NMR makes it difficult to study thin film or nano-sized samples. In this work, we report the first NMR spectrum obtained from general thin films by using magnetic resonance force microscopy (MRFM). To minimize the amount of imaging information inevitably mixed into the signal when a gradient field is used, we adopted a large magnet with a flat end with a diameter of 336 μm that generates a homogeneous field on the sample plane and a field gradient in a direction perpendicular to the plane. Cyclic adiabatic inversion was used in conjunction with periodic phase inversion of the frequency shift to maximize the SNR. In this way, we obtained the (19)F NMR spectrum for a 34 nm-thick CaF2 thin film.

| S-EPMC3824162 | biostudies-other

Localized Strain Measurement in Molecular Beam Epitaxially Grown Chalcogenide Thin Films by Micro-Raman Spectroscopy.

Project description:We developed an experimental metrology for measuring local strain in molecular beam epitaxially (MBE) grown crystalline chalcogenide thin films through micro-Raman spectroscopy. For In2Se3 and Bi2Se3 on c-plane sapphire substrates, the transverse-optical vibrational mode (A1 phonon) is most sensitive to strain. We first calibrated the phonon frequency-strain relationship in each material by introducing strain in flexible substrates. The Raman shift-strain coefficient is -1.97 cm-1/% for the In2Se3 A1(LO + TO) mode and -1.68 cm-1/% for the Bi2Se3 A1g 2 mode. In2Se3 and Bi2Se3 samples exhibit compressive strain and tensile strain, respectively. The observations are compliant with predictions from the opposite relative thermal expansion coefficient between the sample and the substrate. We also map strain cartography near the edge of as-grown MBE samples. In In2Se3, the strain accumulates with increasing film thickness, while a low strain is observed in thicker Bi2Se3 films.

| S-EPMC7161023 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data