Dissertationen zum Thema „Électrolyseurs à membrane électrolyte polymère“
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Krause, Kevin. „Caractérisation infrarouge operando des électrolyseurs à membrane électrolytique polymère pour la séparation de l'eau“. Electronic Thesis or Diss., Bordeaux, 2024. http://www.theses.fr/2024BORD0022.
Der volle Inhalt der QuelleUnderstanding and improving mass and ionic transport mechanisms within the membrane used in polymer electrolyte membrane (PEM) water splitting electrolyzers is vital for achieving improved efficiencies that would enable the use of water electrolysis in sustainable energy infrastructures. A better understanding of mass and ion transport within the PEM are essential to achieving the improved performance and efficiencies necessary for wide-scale commercialization of these devices. The work from this thesis aims to improve characterization methods for measuring PEM hydration using an operating microfluidic PEM electrolysis chip coupled with operando infrared (IR) spectroscopy. This development of this thesis is organized through two parts.In part one and prior to the development of the microfluidic electrolyzer, the experimental setup for IR characterization via Fourier transform infrared spectroscopy (FTIR) and IR thermography was developed. This setup was tested through a microfluidic chip designed for semi-transparency in mid-wave IR light. Two exothermic acid-base reactions were imaged in the chip to simultaneously quantify heat and mass transport in the microfluidic channel. Concentration fields of each chemical species and thermal fields of the chemical reactions were resolved from the acquired IR images. Experimental results were used to validate an advection diffusion simulation of the chemical reaction within a meshed replica of the microfluidic chip, for which there was a strong agreement between the results from each dataset.In part two, the methods from part one were honed for the fabrication of the first microfluidic PEM water electrolyzer for transmission-based IR characterization. The water content within the PEM of the microfluidic water electrolyzer was characterized through two operando IR spectroscopy setups. The first IR experimental setup utilized a synchrotron FTIR spectroscopy setup, where the water content of the PEM was quantified using IR for the first time, albeit only at a single point. The second microfluidic PEM electrolyzer setup used a broadband IR source combined with other techniques to distinguish contributions from ohmic, kinetic, and mass transport losses while acquiring IR images. Images were acquired during potentiostatic operation for a range of anolyte concentrations. Electrochemical impedance spectroscopy (EIS) and distribution of relaxation times (DRT) unveiled that higher anolyte concentrations were accompanied by reduced ohmic losses but higher kinetic and mass transport losses. The higher mass transport losses were investigated through images averaged over comparable time scales to EIS and DRT results, and implied that inefficient gas removal occurred at the cathode. These effects were further investigated through the PEM hydration (λ_(H_2 O)) via three characteristic regions where the adjacent channels were either wet, dry, or a mix of both. The local channel wetness was observed to strongly affect the PEM’s hydration through gradients that manifested between cathode and anode channels.Results from this thesis show the potential of transmission-based IR techniques for elucidating transport mechanisms in PEMs of operating microfluidic electrolyzers. Implementing layers that are traditionally implemented in fuel cells and electrolyzers for gas-liquid management into the microfluidic PEM electrolyzer could greatly improve results obtained from the presented methods. Consequently, IR techniques could potentially be used to achieve the contactless quantification of phenomena such as electro- or thermo-osmotic drag. The findings in this thesis provide valuable insights for membrane characterization in electrochemical devices with integrated PEMs, and will inform the next generation of electrolyzer design
Escribano, Sylvie. „Optimisation de nouvelles électrodes pour piles à combustible hydrogène/oxygène à membrane électrolyte polymère“. Grenoble INPG, 1995. http://www.theses.fr/1995INPG0148.
Der volle Inhalt der QuelleLaflamme, Patrick. „Caractérisation et conception de mélanges polymère/eau pour application aux piles à combustible utilisant une membrane polymère comme électrolyte“. Thèse, Université de Sherbrooke, 2013. http://hdl.handle.net/11143/6685.
Der volle Inhalt der QuelleAgel, Eric. „Electrode à air électrolyte solide polymère alcalin pour piles à combustible et générateur métal-air“. Paris 7, 2002. http://www.theses.fr/2002PA077002.
Der volle Inhalt der QuelleMbemba, Kiele Nsélé. „Assemblages membrane-électrodes exempts de métaux précieux pour l’électrolyse de l’eau à électrolyte polymère solide“. Paris 11, 2010. http://www.theses.fr/2010PA112378.
Der volle Inhalt der QuelleThe work presented here is related to the production of hydrogen and oxygen of electrolytic grade using SPE (Solid Polymer Electrolyte) water electrolysis. In state-of-the-art technology, noble metals are used as electro catalysts: platinum is used at the cathode for the hydrogen evolution reaction and iridium (or its oxides) is used at the anode for the oxygen evolution reaction. Because of their costs, noble metals are limiting the large scale development of this technology, in spite of other advantages. We report here on results obtained concerning the manufacturing and electrochemical characterization of noble-metals-free Membrane Electrode Assemblies (MEA). It is shown that polyoxometalates or cobalt clathrochelates can be used in place of platinum for the hydrogen evolution reaction and that molecular complexes of ruthenium can be used in place of iridium for the oxygen evolution reaction. Additional results related to the development and characterization of anion-conducting polymers are also presented. The electrochemical performances of these new SPE cells are compared to those measured on conventional cells with noble metals
Coulon, Romain. „Modélisation de la dégradation chimique de membranes dans les piles à combustibles à membrane électrolyte polymère“. Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00767412.
Der volle Inhalt der QuelleTran, Thi Bich Hue. „Gestion de l’eau dans les piles à combustible électrolyte polymère : étude par micro-spectroscopie Raman operando“. Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTT198/document.
Der volle Inhalt der QuelleIn a proton exchange membrane fuel cell (PEMFC), the performance and the durability of the system is directly related to the water management in the membrane electrode assembly (AME), particularly in the membrane electrolyte. The optimization of the water repartition, homogeneous and sufficient, is therefore essential to obtain good performance and great durability. The water management in the membrane depends both on the operating conditions and the gas flow-field design. However, the effect of these parameters is not yet fully understood despite numerous studies.In this context, the first part of this thesis focuses on the influence of gas humidification and operating temperature conditions on the performance and the water distribution in a serpentine flow-field cell. The inner water profiles across the membrane thickness at the center of the active surface are recorded by Raman spectroscopy operando. The relationship between the water distribution and the performance of the cell will be discussed. In the second part, the performance and the water distribution in a parallel flow-field cell are studied under the same temperature conditions applied for the serpentine flow-field cell. The results obtained allow us to directly compare the behavior of these two configurations. The origin of their water distribution and performance differences will be discussed. In the third part, we focus on the distribution of water in the plane of a serpentine flow-field cell at different operating temperatures. The cell is powered in counter-flow. The inner water profiles in the membrane are recorded for three zones: inlet, center and outlet. We then trace the water repartition on the cathodic and anodic interfaces. This information gives us a better understanding of the counter-flow effect on the water distribution in the plane of the serpentine flow-field cell
Niether, Christiane. „Étude de l’oxydation électrocatalytique de l’éthanol dans les conditions d’une pile à combustible à membrane électrolyte polymère haute température“. Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS026/document.
Der volle Inhalt der QuelleThe heterogeneous electrocatalytic ethanol oxidation reaction (EOR) in the gas phase has been studied in the temperature range of 120 °C to 180 °C under proton exchange membrane fuel cell (PEM-FC) conditions. Direct ethanol fuel cells (DEFC) offer the possibility to gain electrical energy from a renewable fuel with a pre-existing distribution infrastructure. However the high theoretical energy efficiency that is one of the major advantages of fuel cells cannot be achieved to date with ethanol. Reasons for this are the formation of incomplete oxidation products and inert adsorbates that hinder the electrocatalytic oxidation of ethanol. A better understanding of the reaction mechanism and the influence of reaction conditions is crucial for the optimization of DEFC technology. Several studies have been done on the EOR in aqueous solution, but none so far in the gas phase.For this purpose a test cell with a three electrode assembly has been built. It can operate at temperatures up to 180 °C and is connected to a mass spectrometer for online differential electrochemical mass spectrometry (DEMS) measurements to detect volatile oxidation products in the fuel cell exhaust. Thus the amount of the complete oxidation product carbon dioxide formed during electrooxidation of ethanol can be obtained and allows drawing conclusions on the efficiency of the reaction under varying conditions. In addition a qualitative detection of the side products of the EOR is possible. The effect of temperature on the EOR has been studied on Pt black catalyst in the temperature range of 120 °C to 160 °C. Another focus is the effect of the ethanol concentration on carbon supported Pt/C and PtRh/C catalysts at 150 °C and how the addition of Rh influences the performance and product selectivity of the EOR
Chabé, Jérémy. „Étude des interactions moléculaires polymère-eau lors de l'hydratation de la membrane Nafion, électrolyte de référence de la pile à combustible“. Grenoble 1, 2008. http://www.theses.fr/2008GRE10038.
Der volle Inhalt der QuelleThe Nafion is a polymer. Thanks to its high conductivity (up to ] 0-'< S. Cm-') at high relative humidity (RH), it is a reference electrolyt for a fuel cell. However its conductivity falls during low hydration conditions. To solve this problem, we can add a hygroscopic compound, like ziconium phosphate (ZrP), into the membrane. The conductivity is linked to the structure of the membrane, the proton diffusion mechanisms and the interactions between water molecules and the polymer; we are interested by this last field of research. Infrared spectroscopy are used to establish the hydration mechanisms at a molecular scale for a Nafion and a Nafion-ZrP membrane. This technique can be coupled with a molecular dynamic study, which we have begun for the Nafion. The inftared spectra ofNafion and Nafion-ZrP have been measured on the whole range of RH. We found 5 hydration mechanisms for the Nafion membrane. The ionisation of sulfonic groups S03H is very fast at the beginning ofhydration. Then the protons H+ move away from the sulfonate groups S03- and the net ofhydrogen bonds around these ionic groups changes. For a RH of 40%, bulk water appears inside the membrane. We have thus a "photograph" of the inner membrane at each stage of RH. The adding of an inoganic compound ZrP has no influence on the hydration mechanisms. According to the comparison between our mechanisms and the curve of conductivity, all the sulfonic groups have to be dissociated to reach optimal diffusion ofthe Droton, probablv assured bv the Grotthuss mechanism
Leduc, Marie-Andrée. „Fabrication et caractérisation de poudres de carbone à base de nanostructures pour la couche catalytique des piles à membrane à électrolyte polymère“. Thèse, Université du Québec à Trois-Rivières, 2006. http://depot-e.uqtr.ca/1471/1/000134793.pdf.
Der volle Inhalt der QuelleSavych, Maciejasz Juliia. „Synthèse et caractérisation de nanocomposites platine/nanofibres pour électrodes de pile à combustible à électrolyte polymère“. Thesis, Montpellier 2, 2014. http://www.theses.fr/2014MON20152/document.
Der volle Inhalt der QuelleThe objective of this thesis is to develop corrosion resistant catalyst support materials that can potentially replace carbon in Polymer electrolyte fuel cells. Therefore, Nb doped TiO2 and SnO2 nanofibres and nanotubes were prepared by electrospinning and characterised by X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, N2 adsorption/desorption analysis and electronic conductivity measurements. The obtained Nb doped TiO2 and SnO2 one dimensional structures demonstrated higher conductivity and surface area than non-doped oxides. Pt nanoparticles were prepared using a modified microwave-assisted polyol method and deposited on the electrospun supports. Electrochemical characterisation of the obtained electrocatalysts was performed ex situ using a rotating disc electrode, and compared with a commercial carbon support (Vulcan XC-72R). Pt supported on Nb doped SnO2 provided higher electrochemical stability in comparison to Pt on carbon. Thus, a cathode of Pt/Nb-SnO2 prepared by spray-coating was integrated into Membrane Electrode Assembly (MEA) and characterised in situ in single Polymer electrolyte fuel cell. The MEA exhibited higher durability though lower power density compared to MEA with Pt/C based cathode. Sb doped SnO2 nanotubes have higher conductivity than Nb doped material and when integrated into a cathode, provided enhanced power density in comparison to Nb-SnO2 based cathode
Vinci, Valentin. „Accumulateurs Li/S : barrières organiques à la réactivité des polysulfures“. Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAI043/document.
Der volle Inhalt der QuelleThe 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
Plylahan, Nareerat. „Electrodeposition of Polymer Electrolytes into Titania Nanotubes as Negative Electrode for 3D Li-ion Microbatteries“. Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4049.
Der volle Inhalt der QuelleTitania nanotubes (TiO2nts) as potential negative electrode for 3D lithium-ion microbatteries have been reported. Smooth and highly-organized TiO2nts are fabricated by electrochemical anodization of Ti foil in glycerol or ethylene glycol electrolyte containing fluoride ions and small amount of water. As-formed TiO2nts shows the open tube diameter of 100 nm and the length from 1.5 to 14 µm which are suitable for the fabrication of the 3D microcbatteries. The deposition of PMA-PEG polymer electrolyte carrying LiTFSI salt into TiO2nts has been achieved by the electropolymerization reaction. The morphology studies by SEM and TEM reveal that the nanotubes are conformally coated with 10 nm of the polymer layer at the inner and outer walls from the bottom to the top without closing the tube opening. 1H NMR and SEC show that the electropolymerization leads to PMA-PEG that mainly consists of trimers. XPS confirms the presence of LiTFSI salt in the oligomers.The electrochemical studies of the as-formed TiO2nts and polymer-coated TiO2nts have been performed in the half-cells and full cells using MA-PEG gel electrolyte containing LiTFSI in Whatman paper as separator. The half-cell of TiO2nts (1.5 µm long) delivers a stable capacity of 22 µAh cm-2 over 100 cycles. The performance of the half-cell is improved by 45% at 1C when TiO2nts are conformally coated with the polymer electrolyte. The better performance results from the increased contact area between electrode and electrolyte, thereby improving the charge transport
Ressam, Ibitissam. „Élaboration et caractérisation de nouvelles membranes composites à conduction protonique pour les piles à combustible“. Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066732.
Der volle Inhalt der QuelleThe perfluoro-sulfonated ionomer membranes are employed as separators in many industrialapplications such as fuel cells, chloro-alkali industry, electrodialysis and gaining inclininginterest in aqueous rechargeable or redox-flow batteries where the knowledge of their ionictransport and transfer properties is fundamental.Particularly, Nafion is adopted as a referencemembrane for polymer electrolyte membrane (PEM) fuel cells due to its thermal stability andgood proton conductivity. However, Nafion membranes have several disadvantages such as a decrease in the proton conductivity at low relative humidity (<50%) and high temperatures(>80°C), and excessive dimensional changes due to the swelling/deswelling, leading tomechanical instabilities.To circumvent these problems, novel proton conducting membraneshave been developed, either by completely replacing or by using organic and/or inorganiccomponents to Nafion.3 In this regard, a large spectrum of membranes have been elaboratedconsidering many attributes such as high proton conductivity, physical separation between theanode and the cathode and fuel barrier characteristics, good chemical and physical stability andlow elaboration cost of the membrane. Two types of additives were examined to improve the performances, particularly : Membranes based on Nafion with Chitosan biopolymer. This naturel polymer is consideredas the second most abundant polysaccharide after cellulose.6 Chitosan improves the physical andchemical stability of the membrane in the presence of water, and it is considered as a less costlyadditive to Nafion7.The improvement of the proton conductivity with pristine chitosan isessentially challenging. Previous studies demonstrated that vehicularandGrotthuss mechanismjointly govern the proton transfer in chitosan membranes.In the vehicular mechanism, the protons diffuse together with solvent molecules in the form of hydronium ions byforming acomplex such as H5O2+ and H9O4+. In the Grotthuss mechanism, however, the protons jump fromone solvent molecule or functional group to the next by the continuous formation and breakingof hydrogen bonds. Membranes based on Nafion with Halloysite nanotubes (HNT). These clays confer to themembrane high proton conductivity by constructing large and continuous conductionpathways.These inorganic additives also improve the thermal and mechanical properties of PEM. Composite membranes of Nafion/Chitosan- SO3H and Nafion/HNT-SO3H are prepared. Theresulting composite membranes were studied by various conventional structural characterizationtechniques. H+ conductivity measurements were performed and the values obtained are higherthan those of pristine Nafion at various relative humidity (RH%) levels and temperatures (30°C-80°C). Our results highlight the beneficial character of functionalized chitosan biopolymer andHalloysite nanotube clays as additives to improve PEM performances
Martin, Amélie. „Sulfonation du polyfluorure de vinylidène (PVDF) : Analyse structurale par RMN multinoyaux {1H, 13C, 19F}“. Electronic Thesis or Diss., Normandie, 2022. http://www.theses.fr/2022NORMR117.
Der volle Inhalt der QuelleThe aim of the present work was to understand the sulfonation process of PVDF by chlorosulfonic acid in order to obtain polymer membranes with an optimal sulfonation degree for their further use in PEMFC.At the beginning, the influence of temperature, reaction time and acid concentration on sulfonation was evaluated. The data obtained by FTIR, EA, TGA, DSC and NMR analysis made it possible to reveal the sulfonation mechanism and to show that dehydrofluorination is a necessary and essential condition for the PVDF sulfonation.Taking this to account, the dehydrofluorination of PVDF (d_PVDF) by a strong base, DBU, was initiated and the sulfonation was carried out for the dehydrofluorinated products (S_d_PVDF). The products obtained were analyzed by FTIR, EA, TGA, DSC and NMR in solid-state and the changes in chain mobility due to the sulfonation were correlated with the polymer physico-chemical properties
Bassil, Joëlle. „Développement par procédés plasma de polymères conducteurs protoniques de type phosphonique pour piles à combustible“. Thesis, Montpellier 2, 2014. http://www.theses.fr/2014MON20029/document.
Der volle Inhalt der QuelleThe proton exchange membrane is a key component in the PEMFC-type fuel cell; it plays a decisive role as electrolyte medium for proton transport and barrier to avoid the direct contact between fuel and oxygen. The Nafion® is one of the most extensively studied proton exchange membrane for PEMFC applications. However, it has a number of drawbacks that need to be overcome, especially the poor performance at temperature above 80°C. That's why the development of effective and low cost membranes for fuel cell turned to be a challenge for the membrane community in the last years. Phosphonic acid derivatives are considered suitable candidates as ionomers for application in PEMFC at high temperature (> 80°C) thanks to their efficient proton transport properties under low humidity condition due to their amphoteric character.In this work, plasma polymers containing phosphonic acid groups have been successfully prepared using dimethyl allylphosphonate as a single precursor demonstrating the feasibility of plasma process for the manufacture of proton exchange membranes. Moreover, plasma polymers properties have been investigated as a function of the plasma conditions. The evolution of the films growth rate on three different supports as a function of the plasma discharge power is bimodal, with a maximum (close to 30 nm min-1 on Si) at 60 W. The chemical composition of plasma materials (investigated by FTIR, EDX and XPS) is quite homogeneous from the surface to the bulk; it is characterized by a wide variety of bond arrangements, in particular the presence of phosphonate and phosphonic acid groups which are above all concentrated in the plasma film synthesized at 60 W, characterized by the highest ion exchange capacity (4.65 meq g-1) and the highest proton conductivity (0.08 mS cm-1 at 90°C and 30% RH). TGA analysis has shown that phosphonic acid-based plasma polymers retain water and don't decompose up to 150 °C, which reveals a satisfying thermal stability for the fuel cell application. In terms of fuel retention, plasma films are intrinsically highly performing (methanol, ethanol and glycerol permeabilities being 40 to 235 lower than that of Nafion®211). The plasma films were deposited on fuel cell electrodes (E-TEK®) as binding agents. We have noticed that the phosphonic binder has a sufficient proton conductivity to allow proton transport at the electrode-membrane interface.A second part of this work concerns the surface treatment by plasma process of a conventional phosphonated membrane for improvement of thermal stability and fuel retention. TGA analysis has shown a slight improvement of the thermal stability for the treated membrane. Methanol and ethanol permeabilities tests show that the plasma-modified membrane is 2 to 4 times less permeable than the non-modified membrane. The treatment at 60 W shows the lowest fuel diffusion coefficients (DMeOH = 9.10-12 m2.s-1 and DEtOH = 6.10-12 m2.s-1). Fuel cell tests were realized showing better performance for the modified membrane compared to the non-modified one
Chabe, Jérémy. „Etude des interactions moléculaires polymère-eau lors de l'hydratation de la membrane Nafion, électrolyte de référence de la pile à combustible“. Phd thesis, 2008. http://tel.archives-ouvertes.fr/tel-00285999.
Der volle Inhalt der QuelleLa conductivité est le fait de la structure du matériau, des mécanismes de diffusion du proton, et des interactions eau-polymère au sein de la membrane. Nous nous sommes intéressés à cette dernière partie du problème. Nous avons étudié les mécanismes d'hydratation à l'échelle moléculaire pour les membranes Nafion puis Nafion-ZrP par technique de spectrométrie infrarouge. Cette technique peut être couplée à une étude par dynamique moléculaire que nous avons initié sur le polymère Nafion. Les spectres infrarouges du Nafion et du Nafion-ZrP ont été mesurés sur toute la gamme d'hydratation.
Les résultats obtenus font état de 5 mécanismes d'hydratation successifs pour la membrane Nafion. L'ionisation des groupes sulfoniques SO_3H est très rapide en début d'hydratation. Elle est suivie d'un éloignement des protons H^+ par rapport aux groupes sulfonates SO_3^- dont ils sont issus et d'une réorganisation du réseau de liaisons H autour de ces groupes ioniques. Enfin une eau de type « bulk » apparaît vers 40% d'hydratation. Nous avons ainsi une "photographie" de la membrane à chaque taux d'hydratation. L'ajout d'un composé inorganique ZrP n'influe pas sur les mécanismes d'hydratation.
D'après la comparaison entre nos mécanismes et la courbe de conductivité, il est nécessaire de dissocier tous les groupes sulfoniques pour atteindre une diffusion optimale du proton, probablement assurée par le mécanisme de Grotthuss.