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Laboratoire d'électrochimie et de physicochimie des matériaux et des interfaces (Grenoble)

Overview
Works: 113 works in 120 publications in 3 languages and 194 library holdings
Roles: Other
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Most widely held works by Laboratoire d'électrochimie et de physicochimie des matériaux et des interfaces (Grenoble)
Étude de l'effet de la pression sur les relaxeurs Na0.5/Bi0.5/TiO3 et PbMg0.33/Nb0.66/O3 ainsi que PbMg0.33/Nb0.66/O3-PbTiO3 par diffusion Raman et diffusion des RX by Bacem Chaabane( Book )

2 editions published in 2004 in French and held by 2 WorldCat member libraries worldwide

Relaxor ferroelectrics (relaxors) of a mixed perovskite structure, with the formula A'A"BO3 or AB'B"O3, possess peculiar physical properties related to an intrinsic nano-scaled local structure. The usual approach towards the understanding of the properties of relaxors is through their chemical composition- or temperature-dependent behaviour. In this thesis we have studied the effect of the parameter high pressure on the structure of some examples of relaxors. First, we have investigated the PbMg1/3Nb2/3O3 (PMN) and the Na1/2Bi1/2TiO3 (NBT) under high pressure using X-ray scattering imaging. Large structural modifications with increasing pressure are observed. PMN undergo a phase transition from the low pressure cubic phase to a high pressure rhombohedral phase, characterized by an antiferroeclectric ordering. NBT undergo two phase transitions, from the low pressure rhombohedral phase to an orthorombic phase, then to a high pressure tetragonal phase. For both compounds, a diffuse scattering is observed at low pressure. This diffuse scattering is due to the relaxor-characteristic polar nanoregions and disappears with increasing pressure suggesting a pressure induced disappearance of the polar nanoregions. Second, we have investigated the solid solution PbMg1/3Nb2/3O3-PbTiO3 (PMN1-x-PTx), for the compositions x= 0.1, 0.2, 0.3 and 0.35, under high pressure using Raman spectroscopy. The observed spectral changes are important and point to pressure induced structural modifications. The appearance of a new sharp band for all investigated PMN1-x-PTx compositions allowed us to construct a partial x-p phase diagram which is characterized by a high pressure non-cubic phase
Surface Distortion and Electrocatalysis : Structure-Activity Relationships for the Oxygen Reduction Reaction on PtNi/C Nanocatalysts by Raphaël Chattot( )

1 edition published in 2017 in English and held by 2 WorldCat member libraries worldwide

This PhD thesis was initially motivated by the understanding of the peculiar electrocatalytic activity of hollow PtNi/C nanoparticles for the oxygen reduction reaction (ORR). Investigations on the formation and growth mechanism of this novel class of nanocatalysts using operando X-ray and electron-based techniques revealed that, beyond alloying effects, structural disorder is a lever to boost the ORR kinetics on bimetallic nanomaterials. The 'defects do catalysis' concept was progressively extended to various PtNi catalyst nanostructures, namely to advanced shape-controlled nanocatalysts from the ORR electrocatalysis landscape thanks to fruitful collaborations with European laboratories. This work shows that, through their distorted surface, microstrained nanomaterials feature unprecedented adsorption chemisorption properties and represent a viable approach to sustainably enhance the ORR activity
Accumulateurs Li/S : barrières organiques à la réactivité des polysulfures by Valentin Vinci( )

1 edition published in 2018 in French and held by 2 WorldCat member libraries worldwide

The objectives of this thesis work were to explore new strategies to improve the performance of Li / S accumulators, systems exhibit with high theoretical energy densities whose performance is limited by an electrochemical mechanism including soluble and reactive intermediates. These intermediates induce a low coulombic efficiency and a significant loss of capacity during cycling. Several strategies have been evaluated to create a barrier of organic nature, which mitigate the transport or the reactivity of these polysulfides. The solutions explored are versatile and simple to implement. Good results have been obtained in terms of coulombic efficiency and cyclability, in particular through the use of a polymeric material enables to form ionic interactions with the sulfur intermediates. The mechanism of lithium deposition and dendritic growth has also been studied, for a more complete understanding of the system
Différentes approches d'ingénierie de surface pour des applications biomédicales by Carole Loable( )

1 edition published in 2015 in English and held by 2 WorldCat member libraries worldwide

AISI 316L stainless steel is commonly used as biomaterial because of its desirable properties such as high corrosion resistance. They have, however, the problem of releasing metal ions upon corrosion that may cause allergies to both humans and animals. In addition, implant failures have been reported due to their limited resistance to localised corrosion. There is thus a need to find ways to improve their corrosion resistance. This thesis aims to evaluate different approaches intending to improve the corrosion resistance of AISI 316L stainless steel for biomedical applications using two strategies: (1) modification of the bulk composition and (2) surface modification.The bulk composition of 316L-type stainless steel was modified by adding nitrogen. Laboratory grades with controlled compositions were tested in chloride conditions at a wide range of pH and in simulated physiological conditions. The combination of Mo and N on the pitting potential was found to be beyond the sum of their individual effects, indicating synergy. The effect, however, was found to be pH-dependent, being largely present in acid to neutral chloride conditions and in physiological solutions, while diminishing in high pH. When tested in physiological conditions, this effect was even more beneficial with ageing. Nitrogen was found to enhance the repassivation of the Mo-containing stainless steel grade, driving the potential for passive film breakdown to higher values.The surface of AISI 316L was coated with Fe-based metallic glasses using laser cladding. The resulting coatings had different results depending on the alloy. The coatings of Fe43.2Co28.8B19.2Si4.8Nb4 and Fe60Cr8Nb8B24 showed a matrix with segregations, particularly of Nb, thereby lowering their corrosion resistance. On the other hand, the Fe48.6Mo13.9Cr15.2C14.4Y1.8B6 coating was found to be amorphous but with lower corrosion resistance than the substrate, due to the presence of defects.Ti and TiN were also coated on AISI 316L wires using a prototype for magnetron sputtering in moving deposition mode. In this study, static and semi-continuous modes of motion were used. Overall, the corrosion resistance of the coatings were lower than the substrate, increasing further with coating thickness. The presence of coating heterogeneity allowed for substrate-electrolyte interaction, driving forward corrosion and delamination with further immersion. Deposits of calcium phosphate were found on the coating surface after 14 days of immersion, indicating the possible favourability of bone material growth
Etude Operando des accumulateurs au lithium par couplage spectroscopie à photoémission des rayons X et spectroscopie d'impédance by Jorge Eduardo Morales Ugarte( )

1 edition published in 2019 in English and held by 2 WorldCat member libraries worldwide

Face aux grands défis industriels dans les domaines du stockage électrochimique de l'énergie, un effort de recherche fondamentale sur les matériaux impliqués et leurs interfaces est aujourd'hui indispensable pour un gain en performance, durabilité, sécurité.Dans ce contexte, il est primordial de comprendre les processus interfaciaux mis en jeu qui induisent la dégradation de l'interface lithium métal-électrolyte et entrainent une baisse du rendement Coulombique et favorisent la croissance dendritique.Nous proposons ainsi dans cette thèse une étude couplant des techniques électrochimiques comme la spectroscopie d'impédance avec des techniques d'analyse de surface comme la spectroscopie à photoémission des rayons X pour étudier la réactivité chimique et électrochimiques entre les électrolytes et une électrode de lithium métal.Pour ce faire, un intérêt spécifique a été porté aux électrolytes à base de liquides ioniques, qui ont été proposés comme solvants des sels de lithium, notamment pour leur faible pression de vapeur saturante qui augmente considérablement la sécurité des batteries ainsi conçues.Enfin, ce travail a été consacré en particulier au développement de montages et de mesures operando XPS afin de suivre l'évolution chimique des interfaces à l'intérieur d'une batterie en temps réel
Diagnostic non invasif de piles à combustible par mesure du champ magnétique proche by Mathieu Le Ny( )

1 edition published in 2012 in French and held by 2 WorldCat member libraries worldwide

This thesis proposes a new non invasive technique for fuel cell diagnosis. This technique relies on the measurements of the magnetic field signature created by these systems. By solving an inverse problem, it is possible to get an internal current density map. However, the inverse problem is ill-posed: the solution is not unique and it is extremely sensitive to noise. Regularization techniques were used in order to filter out measurement errors and to obtain physical realistic solutions. In order to improve the quality of the current density estimators, a diagnostic tool was built which is only sensitive to faults occurring inside the fuel cell (fault sensor). More over, our approach is based on a very low number of measurements. Such technique simplifies the experimental setup and improves the accuracy and the speed of the diagnostic tool. The sensitivity of our tool to some faults (drying out, oxygen starvation and ageing) is demonstrated
Développement et optimisation d'un système de stockage d'énergie et de production d'hydrogène basé sur l'électrochimie et la chimie du zinc by François Guillet( )

1 edition published in 2019 in French and held by 2 WorldCat member libraries worldwide

Hydrogen is an energy carrier and a potential asset for helping to lower carbon levels of energetic uses. Water electrolysis is a way of production and a good compromise to generate a large quantity of cheap and low-environmental-impact hydrogen. Compression is used to store hydrogen but electrolysers are technologically limited to reach high pressures. One solution to overcome this problem is decoupling electrolysis. It aims at separating the hydrogen and oxygen production in two steps through mediation oxydizer/reducer. Ergosup company has developed ZHYNCELEC process, using different technologies such as zinc as mediator. The first step is zinc electrodeposition which increases the acidity of solution and lead to an oxygen formation. This step is inspired by industrial zinc electro winning. The second step is the reaction between the metallic deposition and electrolyte producing hydrogen and making the dissolution of zinc. The purpose of this study is the optimisation of ZHYNCELEC process.This work can be divided in three axes of study. First, the selection of the different electrode materials. They are chosen by electrochemical performances and durability. Secondly, electrolyte composition optimization. The key factors are zinc concentration, acid concentration and the possibility of additives presences. The final axe concerns the processing aspect and the operative conditions like temperature, current density, maximal hydrogen pressure and reactor geometry. These three axes cannot be studied separately because of the interaction between the different parameters, which forces at compromising following the aim of the application of the process
Etude des mécanismes de corrosion sous contrainte des aciers inoxydables supermartensitiques en milieu H2S by Martin Monnot( )

1 edition published in 2017 in French and held by 2 WorldCat member libraries worldwide

Super martensitic stainless steels are widely used in the oil and gas industry, but failures occurred in service under severe conditions. The aim of this study is to provide a better understanding of the stress corrosion mechanism in H2S medium. For this purpose, laboratory heats have been casted with different molybdenum contents, a component known to improve corrosion resistance. These additions of alloying elements then involve a fine characterization of the microstructure, in order to grasp the mechanisms of rupture. Particular attention has been paid to the evolution of the retained austenite and residual ferrite fraction with the heat treatments of quench and annealing which are commonly practiced on these grades. Then, by electrochemical measurements without mechanical stress, the addition of molybdenum was identified as beneficial for the passivity of the grade in the H2S medium. And for 2.25% molybdenum contents, corrosion products have been identified as mainly nickel sulfides, which are inhibitors of hydrogen recombination. Subsequently, corrosion tests under static and dynamic load coupled to electrochemical impedance measurements show a beneficial effect of molybdenum and residual austenite. In particular, molybdenum reduces the defects of the passive film. A finite elements model simulates the slow strain rate traction tests taking into account the hydrogen embrittlement. In order to use experimental parameters, an electrochemical permeation cell was implemented and used to measure the hydrogen diffusion coefficient within our different heats. A good match with the experimental results was obtained with this model and a parametric study was carried out on the diffusion coefficient and the hydrogen interfacial concentration. Finally, a synthesis provides the proposal of a stress corrosion mechanism divided in two steps: the passive film resistance to limit the hydrogen absorption in the matrix and the trapping of the hydrogen by the residual austenite in function deformation
Développement d'un procédé de production d'hydrogène photofermentaire à partir de lactosérum by Patricia Castillo Moreno( )

1 edition published in 2018 in Spanish and held by 2 WorldCat member libraries worldwide

L'hydrogène est une source d'énergie précieuse en tant que source d'énergie propre et que matière première pour des innombrables industries.Les procédés biologiques de production d'hydrogène gagnent en importance en raison de leurs avantages opérationnelles et de leur polyvalence dans les substrats utilisés (y compris les eaux usées).Dans cette thèse doctoral, on a développé une méthodologie photo-fermentative de production d'hydrogène en utilisant du lactosérum en tant que substrat pour la bactérie Rhodobacter capsulatus IR3::LacZ et B10::LacZ.Ce projet a été réalisé en trois étapes, exposées dans les différents chapitres.Dans la première étape on a identifié les facteurs pertinents pour la production de l'hydrogène avec du sérum synthétique en utilisant la méthodologie de plan d'expériences.Les résultats de cet étape on a obtenu quatre modèles statistiques et on a choisi la souche IR3::LacZ pour les expériences avec du lactosérum industriel.Le rendement volumétrique maximal et le rendement produit / substrat Y P/S obtenus pour la première étape ont été de 64 ml h-1L-1 et 2,08 mol H2 mol-1 C (“C” représente la source de carbone dans ce cas lactose et lactate) pour la solution amortissant le phosphate et 43.01 ml h-1L-1 y 2.52 mol H2 mol-1 C pour la solution Kolthoff.Dans la deuxième étape, on a évalué la production d'hydrogène avec du lactosérum industriel. On a appliqué un pré-traitement de trois étapes avant d'utiliser le lactosérum comme substrat : réduction du contenu gras, déprotéinisation et stérilisation. On a obtenu un modèle validé qui décrit la production d'hydrogène seulement pour la solution amortissant de phosphate. Le rendement volumétrique maximal et le YP/S ont été de 45.93 ml h-1L-1 et de 2.29 mol H2 mol-1 C respectivement. On a déterminé que l'addition d'une étape d'homo-fermentation au processus de prétraitement es avantageuse au rendement du processus. On a obtenu une productivité volumétrique de 69.71 ml h-1L-1 et de YP/S de 2.96 mol H2 mol-1 CLa troisième étape a été la mise à l'échelle des expériences à réacteurs de 1,5 L pour sérum synthétique et de 1L pour serum industriel. On a décelé de la contamination dû à la présence d'un processus de fermentation, lequel a généré une haute production de biogas composé exclusivement par H2 y CO2 ce dernier dans une concentration non superieur à 30% (v/v).Pour ces raisons, on a conclu que conclu que le processus de production intégré, en couplant la fermentation obscure et la photo-fermentation est une option avec un énorme potentiel pour l'utilisation de lactosérum comme substrat dans la production d'hydrogène
Towards microbial electrochemical technologies for metal recovery by Juan Anaya garzon( )

1 edition published in 2019 in English and held by 2 WorldCat member libraries worldwide

Metals, essential constituents of a vast number of products and industrial processes, are paradoxically confronted to a scarcity issue without precedents. Among the emerging technologies for sustainable metal recovery, bio-electrochemical systems (BES) stand at a research state with a potential application on low-content metal streams. They are based on electroactive bacteria that can exchange electrons with their environment to drive an (electro)chemical metal precipitation. The feasibility of three configurations of BES aiming to recover metals at low-energy and low-chemicals consumption was explored. A first approach inspired on metal-bacteria interactions aimed to transform gold and chromium ions into added-value products. A polarized cathode promoting the metal reduction and symbiotically producing metallic nanoparticles on bacteria was studied. A second configuration used a halophilic bioanode to recover a panel of metals including transition metals and rare earth elements from marine environments. Metals were not directly precipitated by the contact with bacteria, but via a gas-diffusion cathode coupled to the bioanode. The third configuration considered a neodymium electrochemical reduction coupled to an oxidation catalyzed by a bioanode. Here, the conventional metal-containing aqueous system was replaced by an ionic liquid, an emerging solvent suitable for REE electrodeposition
Study of a buffer layer based on block copolymer electrolytes, between the lithium metal and a ceramic electrolyte for aqueous Lithium-air battery by Louise Frenck( )

1 edition published in 2016 in English and held by 2 WorldCat member libraries worldwide

The lithium-air (Li-air) technology developed by EDF uses an air electrode which works with an aqueous electrolyte, which prevents the use of unprotected lithium metal electrode as a negative electrode. A Li+ ionic conductor glass ceramic (LATP:Li1+xAlxTi2-x(PO4)3) has been used to separate the aqueous electrolyte compartment from the negative electrode. However, this glass-ceramic is not stable in contact with lithium, it is thus necessary to add between the lithium and the ceramic a buffer layer. In another hand, this protection should ideally resist to lithium dendritic growth. Thus, this project has been focused on the study of block copolymer electrolytes (BCE).In a first part, the study of the physical and chemical properties of these BCEs in lithium symmetric cells has been realized especially transport properties (ionic conductivities, transference number), and resistance to dendritic growth. Then, in a second part, the composites BCE-ceramic have been studied.Several characterization techniques have been employed and especially the electrochemical impedance spectroscopy (for the transport and the interface properties), the small angle X-ray scattering (for the BCE morphologies) and the hard X-ray micro-tomography (for the interfaces and the dendrites morphologies). For single-ion BCE, we have obtained interesting results concerning the mitigation of the dendritic growth. The hard X-ray micro-tomography has permitted to show that the mechanism involved in the heterogeneous lithium growth in the case of the single-ion is very different from the one involved for the neutral BCEs (t+ < 0.2)
Développement de cathodes performantes pour batteries lithium/air by Sophie Berenger( )

1 edition published in 2014 in French and held by 2 WorldCat member libraries worldwide

Croissance épitaxiale, caractérisation structurale et études magnétiques de couches minces d'UO2 by Zhaohui Bao( )

1 edition published in 2013 in English and held by 2 WorldCat member libraries worldwide

We have investigated structural and magnetic properties of epitaxial UO2 andUO2/Fe3O4 thin films fabricated by reactive DC-sputtering. The UO2 layer grew commensurately on LaAlO3 substrate with epitaxial relationships of (001)UO2 Î (001)LAO and <100>UO2 Î <110>LAO. Due to the pseudomorphic growth which extended up to 45 Å, a strain (Á) of about 2% were introduced into the UO2 epilayer. A partial relaxation process was observed for films thicker than 500 Å. The large mosaic affects strongly the magnetic properties. Rosonant X-ray scattering studies revealed that the Néel temperature remained at 30.8 K. However, a small reduction of TN is expected at tuo2 ~ 50 Å. The second-order phase transition was found for films with thickness between 181 and 4500 Å. Using the Bernhoeft plot, the thickness of the magnetically ordered phase was estimated. The pseudomorphic part was magnetically inactive. The exchange bias studies confirmed this result. For the first time, the magnetocrystalline anisotropy constant of UO2 was found to be about 1 x 107 erg/cm3
Synthèse et caractérisation de matériaux polymères conducteurs protoniques pour membranes de pile à combustible by Xavier Thiry( )

1 edition published in 2013 in French and held by 2 WorldCat member libraries worldwide

This thesis deals with the conception of proton conducting materials used as PEMFCmembrane. The proposed approach is quite new in this application field and is based on thedevelopment of semi-interpenetrating networks (semi-IPN). A linear conducting polymer(sulfonated PEEK) was combined with a crosslinked fluorinated network, a poly(aryl etherperfluorocyclobutane) (PFCB). These macromolecules are obtained by thermalcyclodimerization of bis and tris trifluorovinylether monomers (TFVE). Different series ofsemi-IPN were prepared by changing the PFCB nature, the crosslinking degree, the synthesisprocess and the proportion of the network added to the sPEEK. The overall results show aspecific semi-IPN composition for which the conductivity, the swelling and mechanicalstrength properties are optimal. A membrane with a proton conductivity of 155 mS.cm-1 and alimited water swelling (50 % lower than for a sPEEK membrane which exhibits a protonconductivity of 127 mS.cm-1) is obtained by adding 10 wt-% of fluorinated network. Inaddition, the incorporation of sulfonated TFVE monomers into the network PFCB has beenconsidered. A significant effort in organic chemistry enabled the synthesis of bis-TFVEmolecules containing protected sulfonated functions in a sulfonate ester form. Linearconducting PFCB polymers with a predeterminated IEC were obtained by directcopolycondensation of these monomers
Mécanismes de dégradation des catalyseurs modèles anodiques à base d'iridium dans les électrolyseurs de l'eau PEMWE by Marion Scohy( )

1 edition published in 2019 in French and held by 2 WorldCat member libraries worldwide

With the need for a drastic reduction of greenhouse gases, the deployment of fuel cells is one of the considered solutions. Decarbonated hydrogen production is subsequently a major challenge to enable an efficient energetic transition. From this perspective, Proton Exchange Membrane Water Electrolyser (PEMWE) is a technology of interest, especially if coupled with renewable energy sources. Key challenges are still to be addressed before commercializing this technology, in particular at the anode. Iridium oxide, a costly and rare material, is implemented in anodic catalytic layers to catalyse the Oxygen Evolution Reaction (OER) while being resistant to harsh acidic and oxidative conditions. It nonetheless undergoes some degradations.In this work, different iridium model surfaces for the OER where studied to understand mechanisms involved during the first oxidations step and oxygen evolution. After characterisations by Dynamic Electrochemical Impedance Spectroscopy (DEIS), an innovative technique used to study dynamic systems, structure-activity-stability relationships towards the OER were studied by comparing iridium model surfaces ((111), (210) and nanostructured (210)). Results showed that after few hours at high potential (> 1.6 V vs. Reversible Hydrogen Electrode)), these surfaces, with different initial chemical compositions and structures, tend to the same state. Finally, iridium and [email protected] thin films were studied, to model [email protected] particles. Results indicate that the nickel dissolution lead to the formation of a porous layer more active towards the OER. These findings could help to design active iridium catalysts for the OER
Synthèse et caractérisation de nouveaux électrolytes copolymères pour batteries lithium métal polymère. by Adrien Lassagne( )

1 edition published in 2017 in French and held by 2 WorldCat member libraries worldwide

This work deals with synthesis and characterization of new polymer electrolytes for lithium metal polymer (LMP) batteries. The main challenge of polymer electrolytes is to combine both high ionic conductivity at low temperature and good mechanical properties. To overcome these issues, block copolymers have been designed. Remarkable properties are reached thanks to the self-assembly of these triblock copolymers. Mechanical properties are given by stiff polystyrene (PS) domains whereas ionic mobility operates in an ionophilic phase, polyoxyethylene (POE) with a lithium salt (LiTFSI). By introducing chemical defects in the POE backbone, melting temperature of the copolymer has been considerably lowered leading to conductivities of about 7.10-5 S.cm-1 and a Young's modulus of 0.3 MPa at 40°C. If interesting properties are obtained thanks to this strategy, the small fraction of conductivity insured by lithium ions (t+=0.15) remains an issue. The low t+ leads to large concentration gradients limiting the performances of the system. In a second approach, TFSI anions have been covalently tethered on the PS backbone, raising the t+ to 1. An important increase of Li+ conductivity was obtained by adding a perfluorinated spacer between PS and TFSI moieties, with an ionophilic phase based on PEO (2.10-5 S.cm-1 @ 60°C). The chemical modification of the PEO block leads to Li+ conductivities of 10-6 S.cm-1 at 40°C. The composition of these different copolymers have been varied and their structural, thermal, mechanical and transport properties have been studied. Finally the best electrolytes of each category have been assessed in a full cell configuration
Étude du vieillissement des isolants synthétiques des câbles moyenne tension "HTA". by Quentin Pelzer( )

1 edition published in 2019 in French and held by 2 WorldCat member libraries worldwide

Le PRC (Polyéthylène réticulé chimiquement) est utilisé comme matériau de base pour la fabrication de l'enveloppe à isolation électrique des câbles HTA en raison de ces propriétés thermiques et diélectriques remarquables. Afin d'améliorer la fiabilité de ces câbles, des études de vieillissement sous différentes contraintes (thermique, humidité, tension) ont été réalisées sur les différentes couches du câble, et en particulier sur l'isolant en PRC.Dans un premier temps, nous avons identifié un certain nombre de marqueurs chimiques et physiques pouvant donner des informations sur le degré de vieillissement de l'isolant PRC des câbles HTA. Ces différents marqueurs sont caractéristiques d'une dégradation multi-échelle (moléculaire, microscopique et macroscopique) et peuvent être utilisés pour établir le diagnostic d'un câble électrique et ainsi évaluer son état de dégradation général. Parmi ces marqueurs, l'existence d'un phénomène de migration d'espèces polaires des semi-conducteurs vers l'isolant du câble aura particulièrement attiré notre attention. Des analyses supplémentaires ont donc été réalisées afin de mieux appréhender ce phénomène.Ensuite, nous avons déterminé l'impact de contraintes thermique et électrique simultanées sur les propriétés physico-chimiques et diélectriques d'un isolant en PRC. Les analyses physico-chimiques ont montré que l'ajout d'une forte tension ne semble affecter ni l'oxydation, ni la diffusion. Des vieillissements sous contraintes importantes ont néanmoins permis d'identifier un signal particulier en spectroscopie diélectrique. La détection de ce signal pourra être utilisée pour anticiper des claquages de câbles sur le réseau électrique. Nous avons également réussi à établir un lien entre certains marqueurs chimiques et la dégradation des propriétés diélectriques des isolants pour des mises sous contraintes particulièrement extrêmes
Développement et compréhension des mécanismes électrochimiques des accumulateurs Lithium-ion/Soufre by Alice Robba( )

1 edition published in 2018 in French and held by 2 WorldCat member libraries worldwide

Modélisation électrochimique du comportement d'une cellule Li-ion pour application au véhicule électrique by Andrea Falconi( )

1 edition published in 2017 in English and held by 2 WorldCat member libraries worldwide

The future development of electric vehicles is mostly dependent of improvements in battery performances. In support of the actual research of new materials having higher performances in terms of energy, power, durability and cost, it is necessary to develop modeling tools. The models are helpful to simulate integration of the battery in the powertrain and crucial for the battery management system, to improve either direct (e.g. preventing overcharges and thermal runaway) and indirect (e.g. state of charge indicators) safety. However, the battery models could be used to understand its physical phenomena and chemical reactions to improve the battery design according with vehicles requirements and reduce the testing phases. One of the most common model describing the porous electrodes of lithium-ion batteries is revisited. Many variants available in the literature are inspired by the works of prof. J Newman and his research group from UC Berkeley. Yet, relatively few works, to the best of our knowledge, analyze in detail its predictive capability. In the present work, to investigate this model, all the physical quantities are set in a dimensionless form, as commonly used in fluid mechanics: the parameters that act in the same or the opposite ways are regrouped and the total number of simulation parameter is greatly reduced. In a second phase, the influence of the parameter is discussed, and interpreted with the support of the limit cases. The analysis of the discharge voltage and concentration gradients is based on galvanostatic and pulse/relaxation current profiles and compared with tested commercial LGC cells. The simulations are performed with the software Comsol® and the post-processing with Matlab®. Moreover, in this research, the parameters from the literatures are discussed to understand how accurate are the techniques used to parametrize and feed the inputs of the model. Then, our work shows that the electrode isotherms shapes have a significant influence on the accuracy of the evaluation of the states of charges in a complete cell. Finally, the protocols to characterizes the performance of commercial cells at different C-rates are improved to guarantee the reproducibility
Recyclage de métaux venant d'accumulateurs NiMH : développement d'extractions liquide-liquide sélectives à partir de liquides ioniques by Matthieu Gras( )

1 edition published in 2018 in English and held by 2 WorldCat member libraries worldwide

Nickel-metal hydride (NiMH) batteries are currently dominating the market of energy storage in hybrid electric vehicles. 1 billion cells are estimated to be produced each year. In their end-of-life, these electronical wastes exhibit low recycling rates, despite the fact that NiMH batteries contain high amounts of valuable and strategic metals. Two main metal families coexist as an intermetallic compound in negative electrodes: transition metals (TM) (Ni, Co, Mn and Fe) and rare earth elements (REE) (La, Ce, Nd and Pr). Among TM, cobalt exhibits the highest criticality rate. Indeed, natural ores will not cover the increasing cobalt demand linked to emerging technologies. REE produced at more than 97 % in China are at the centre of European Union's preoccupations. To tackle economic and environmental issues, this project, supported by the labex CEMAM is a partnership between the company Recupyl® and the academic laboratory LEPMI. It aims at investigating on low environmental impact routes for the recycling of metals present in real spent NiMH batteries. This requires the replacement of volatile organic compounds by ionic liquids, respecting the principles of 'green chemistry'. Based on innovative extraction and recovery processes of elements by hydrometallurgy and electrochemistry, we propose a flowsheet for the valorisation of metals from those batteries
 
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Laboratoire d'électrochimie et de physicochimie des matériaux et des interfaces (Chambéry)

LEPMI

UMR 5279

UMR 5631

UMR5279

UMR5631

Unité Mixte de Recherche 5279

Unité Mixte de Recherche 5631

Université Joseph Fourier (Grenoble). Laboratoire d'électrochimie et de physicochimie des matériaux et des interfaces

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