Li+ distribution into V2O5 films resulting from electrochemical intercalation reactions

We studied interface effects of thin film V2O5 electrodes on top of indium tin oxide (ITO) glass for Li intercalation by means of a combination of methods: depth-profiling by secondary ion mass spectroscopy (SIMS), electrochemical insertion-extraction of lithium ions by slow-scan cyclic voltammetry (SSCV) and by potentiostatic intermittent titration technique (PITT). We show that the Li+ distribution inside the oxide film is always far from homogeneous, and that different diffusion paths (parallel to interfaces as well as perpendicular to them) have to be considered in experiments with electrodes having areas of few cm². The exposed edge formed when cutting out coupons from the coated glass plate supporting the V2O5 electrode plays a significant role in the process, because it exposes the V2O5-ITO interface to the electrolyte.Estudamos os efeitos de interface de filmes finos de eletrodos de V2O5 sobre vidros com óxido de índio-estanho (ITO) para intercalação de Li utilizando combinações de métodos: perfil de profundidade por espectrometria de massas de íons secundários (SIMS), inserção-extração eletroquímica de íons lítio por voltametria cíclica de varredura lenta (SSCV) e por técnica de titulação potenciostática intermitente (PITT). Nós demonstramos que a distribuição de Li+ no interior do filme de óxido é sempre distante de ser considerada homogênea e que diferentes etapas de difusão (paralelas às interfaces e bem como perpendiculares a elas) são consideradas por conter áreas de alguns cm² em experimentos com eletrodos. A margem exposta pelo corte da placa de vidro revestida com ITO e recoberta com V2O5 desempenha um papel importante no processo, pelo fato de expor a interface V2O5-ITO ao eletrólito.66767

Atomic layer deposition of Nb-doped SnO2 thin films: deposition process and properties of the film

International audienc

Analysis of Cu(In,Ga) Se 2 grading evolution during low deposition temperature co-evaporation process by GD-OES and XPS measurements. Impact on solar cell performances and modelling

International audienc

XPS and TOF-SIMS study of the distribution of Li ions in thin films of vanadium pentoxide after electrochemical intercalation

The intercalation of vanadium pentoxide by lithium ions leads to a change in optical properties, a process that is of value in thin-film electrochromic devices. The extent of intercalation can be measured, electrochemically, from the charge capacity of the film and, is in good agreement with that determined in the outermost layers by X-ray photoelectron spectroscopy (XPS), when intercalation occurs homogeneously through the film thickness. SIMS profiles of V2O5-deposited on ITO-glass coupons have allowed examination of the interface between these layers and in prior work showed a marked build up of Li in this interphase. Investigation of the distribution of lithium within the interphase showed it to be present in parts of the testpiece that were not immersed in the electrolyte used for Li insertion. In this work we have tested the suggestion that the lithium found in the interface can be introduced, during intercalation, via the exposed edge of the V 2O5/ITO interface at the periphery of the sample. A series of intercalation cycles using modified cells to expose either: a) the periphery; or b) the centre; of the thin film have been carried out. The distribution of lithium after intercalation has been examined using a combination of ToF-SIMS and XPS. XPS showed lithium in the film to be related only to the immersed regions of the testpiece whilst SIMS profiles confirmed the widespread distribution of Li through the interface, only when an edge was exposed. We work confirms an important influence of an unsealed edge when samples are produced by cutting from larger glass plates. Copyright © 2008 John Wiley & Sons, Ltd

Improving V oc With Indium and Alkali Fluorides in Cu(In,Ga)Se 2 Solar Cells Deposited at Low Temperature on Polyimide

International audienc

Li+ distribution into V2O5 films resulting from electrochemical intercalation reactions

We studied interface effects of thin film V2O5 electrodes on top of indium tin oxide (ITO) glass for Li intercalation by means of a combination of methods: depth-profiling by secondary ion mass spectroscopy (SIMS), electrochemical insertion-extraction of lithium ions by slow-scan cyclic voltammetry (SSCV) and by potentiostatic intermittent titration technique (PITT). We show that the Li+ distribution inside the oxide film is always far from homogeneous, and that different diffusion paths (parallel to interfaces as well as perpendicular to them) have to be considered in experiments with electrodes having areas of few cm². The exposed edge formed when cutting out coupons from the coated glass plate supporting the V2O5 electrode plays a significant role in the process, because it exposes the V2O5-ITO interface to the electrolyte

Li+ distribution into V2O5 films resulting from electrochemical intercalation reactions

We studied interface effects of thin film V2O5 electrodes on top of indium tin oxide (ITO) glass for Li intercalation by means of a combination of methods: depth-profiling by secondary ion mass spectroscopy (SIMS), electrochemical insertion-extraction of lithium ions by slow-scan cyclic voltammetry (SSCV) and by potentiostatic intermittent titration technique (PITT). We show that the Li+ distribution inside the oxide film is always far from homogeneous, and that different diffusion paths (parallel to interfaces as well as perpendicular to them) have to be considered in experiments with electrodes having areas of few cm(2). The exposed edge formed when cutting out coupons from the coated glass plate supporting the V2O5 electrode plays a significant role in the process, because it exposes the V2O5-ITO interface to the electrolyte