Search results for "electrolyte"
showing 10 items of 746 documents
Gas sensitive luminescence of ZnO coatings obtained by plazma electrolytic oxidation
2015
Abstract The ZnO coatings on Zn substrate were obtained using plasma electrolytic oxidation method. The XRD and SEM methods were used for structural and morphological characterization of obtained coatings. The luminescence of ZnO coatings were studied and compared with luminescence characteristics of ZnO single crystal. It is shown that luminescence intensity in ZnO defect band depends on oxygen concentration in ambient atmosphere. The effect is of interest for oxygen sensing based on ZnO coating luminescence.
Energy Conversion: Solid Oxide Fuel Cells: First-Principles Modeling of Elementary Processes
2013
Fuel cells are electrochemical devices that directly transform the chemical free energy of combustion (e.g., H2 + O2 and CHx + O2) into electrical energy. The avoidance of a thermal detour guarantees high theoretical efficiency. As far as the temperature regimes are concerned, we distinguish between high temperature ceramic fuel cells, intermediate-temperature fuel cells, and low temperature (i.e., only slightly above room temperature) fuel cells. The high temperature fuel cells are usually based on oxide components (ternary transition metal oxides as cathodes, Ni or Cu cermets as anodes, and acceptor-doped zirconia or ceria as electrolytes). The high temperature necessary for ion conductio…
Kinetic Ionic Permeation and Interfacial Doping of Supported Graphene
2019
Due to its outstanding electrical properties and chemical stability, graphene finds widespread use in various electrochemical applications. Although the presence of electrolytes strongly affects its electrical conductivity, the underlying mechanism has remained elusive. Here, we employ terahertz spectroscopy as a contact-free means to investigate the impact of ubiquitous cations (Li+, Na+, K+, and Ca2+) in aqueous solution on the electronic properties of SiO2-supported graphene. We find that, without applying any external potential, cations can shift the Fermi energy of initially hole-doped graphene by ∼200 meV up to the Dirac point, thus counteracting the initial substrate-induced hole dop…
Manufacturing and testing of a metal supported Ni-YSZ/YSZ/La2NiO4 IT-SOFC synthesized by physical surface deposition processes
2017
International audience; The manufacture of the last generation metal supported IT-SOFC complete cell by dry surface deposition pro-cesses is really challenging. Atmospheric Plasma Spraying (APS) and Reactive Magnetron Sputtering (RMS) processes are respectively adapted to deposit Ni-YSZ anode and YSZ electrolyte layers. RMS is also used to coat a thin and dense La2NiO4 (LNO) cathode layer. In this work, we have realized a complete cell on metallic support (ITM) produced by PLANSEE SE. The innovative LNO cathode layer was compared with screen-printed LNO layers, with and without RMS bonding layer. Electrochemical and Voltammetry tests were performed on these samples. It reveals lower perform…
Microstructural corrosion of aluminium alloys: a predictive finite element model based on corrosion-mimicking experiments
2013
The purpose of this study is to implement the basis of a finite element model (FEM) based on the resolution of the Nernst–Planck equation in order to progress in the predictive simulation of microstructural corrosion on aluminium alloys. Certain constituent intermetallic particles at the surface of aluminium alloys are considered as preferential sites for the initiation of structural corrosion resulting in localised trenching around the particles and the surrounding Al matrix. In this work, a modified scanning electrochemical microscope (SECM) experiment was used to induce such phenomena via a local alkalinization on 200 nm thick aluminium coatings, promoting their local dissolution in an a…
Nanostructured anode material for Li-ion batteries
2010
The present paper focuses on a nanostructured SnCo alloy electrochemically prepared by template method in view of its use as anode material alternative to graphite in lithium-ion batteries. The fabrication of SnCo nanowire arrays was carried out by potentiostatic co-deposition of the two metals by using nanostructured anodic alumina membranes as template. Electrochemical tests on lithiation-delithiation of these SnCo electrodes in conventional organic electrolyte (EC:DMC LiPF6) at 30°C showed that their specific capacity was stable for about the first 12 cycles at a value near to the theoretical one for Li22Sn5 and, hence, progressively decayed.
Simulation of pH-controlled dissolution of aluminium based on a modified Scanning Electrochemical Microscope experiment to mimic localized trenching …
2011
Abstract Some constituent intermetallic (IMPs) particles at the surface of aluminium alloys are considered as preferential sites for the initiation of structural corrosion resulting in localized trenching around the particles and the surrounding Al matrix. In this work, a modified scanning electrochemical microscope (SECM) experiment was used to induce such phenomena via a local alcalinisation on 200 nm thick aluminium coatings promoting their local dissolution in an aerated 0.1 M NaCl electrolyte. The local alcalinisation was induced by the oxygen reduction reaction on the tip of a SECM which mimics the surface of an isolated IMP. From a phenomenological point of view, reproducible cylindr…
Growth and Electrical Characterization of Horizontally Aligned CNTs
2009
Nickel catalyst nanoparticles acting as nucleating seeds for carbon nanotube (CNT) growth were selectively deposited on the sidewalls of titanium nitride (TiN) electrodes by electrochemical deposition (ECD) from a Ni2+ electrolyte solution. Horizontal aligned CNTs were grown selectively from the sidewalls of these TiN electrodes forming a bridging CNT contact between the electrode gaps. Current-voltage measurements demonstrated this could be a promising technique towards nanoscale interconnections and nanoelectronic devices with resistance values for the bridging CNTs as low as 300Ω.
Novel tree-like WO3 nanoplatelets with very high surface area synthesized by anodization under controlled hydrodynamic conditions
2016
In the present work, a new WO3 nanostructure has been obtained by anodization in a H2SO4/NaF electrolyte under controlled hydrodynamic conditions using a Rotating Disk Electrode (RDE) configuration. Anodized samples were analyzed by means of Field Emission Scanning Electronic Microscopy (FESEM), Confocal Raman Microscopy and photoelectrochemical measurements. The new nanostructure, which consists of nanoplatelets clusters growing in a tree-like manner, presents a very high surface area exposed to the electrolyte, leading to an outstanding enhancement of its photoelectrochemical activity. Obtained results show that the size of nanostructures and the percentage of electrode surface covered by…
Influence of electrolyte temperature on the synthesis of iron oxide nanostructures by electrochemical anodization for water splitting
2018
[EN] Iron oxide nanostructures are an attractive option for being used as photocatalyst in photoelectrochemical applications such as water splitting for hydrogen production. Nanostructures can be obtained by different techniques, and electrochemical anodization is one of the simplest methods which allows high control of the obtained morphology by controlling its different operational parameters. In the present study, the influence of the electrolyte temperature during electrochemical anodization under stagnant and hydrodynamic conditions was evaluated. Temperature considerably affected the morphology of the obtained nanostructures and their photoelectrochemical behavior. Several techniques …