Dissertations / Theses on the topic 'Electrolyte solvent'
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Klein, Jeffrey M. "Electrode-Electrolyte and Solvent-Solute Interfaces of Concentrated Electrolytes: Ionic Liquids and Deep Eutectic Solvents." Case Western Reserve University School of Graduate Studies / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=case1620213066452923.
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Urata, Tomoko. "Morphology Control of Anodized Porous Silicon from the Viewpoint of Solvent in Electrolyte Solutions." 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/217176.
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Higashino, Shota. "Electrodeposition of reactive metals and alloys from non-aqueous electrolytes and their applications." Kyoto University, 2020. http://hdl.handle.net/2433/259066.
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Dougassa, Yvon. "Propriétés de transport et solubilité des gaz dans les électrolytes pour les batteries lithium-ion." Thesis, Tours, 2014. http://www.theses.fr/2014TOUR4035/document.
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Lors du fonctionnement des batteries Li-ion, la dégradation progressive de l’électrolyte engendre la génération des gaz qui sont à l’origine du phénomène des surpressions dans ces dispositifs, et a pour conséquence des problèmes de sécurité. Cette thèse aborde l’étude de la solubilité des gaz issus des réactions de dégradation des électrolytes tels que le CO2, CH4, ou encore C2H4 dans plusieurs systèmes simples (solvants purs) ou complexes (mélanges binaires, ternaires et quaternaires avec sel de lithium), en fonction de la température, de la structure des solvants et des sels, ainsi que de leurs concentrations en solution. A cet effet, nous avons mesuré préalablement les propriétés volumétriques, de transport, ainsi que les pressions de vapeur des électrolytes formulés en fonction de la composition et de la températureThe performance and the safety of a lithium-ion battery depend to a great extent on the stability of the electrolyte solution, because the high voltage of the battery may cause the decomposition of lithium salt or organic solvents, which limits then the battery lifetime. During these degradations, several gases are, generally, generated like the CO2, CO, CH4 and C2H4, which induce in fact several problems related to the pressure increase inside the sealed cell. The main objective of this PhD thesis is to understand the key thermodynamic parameters which drive the gas dissolution in classical solvents and electrolytes. For that, several pure solvents and electrolytes have been firstly investigated to determine their volumetric and transport properties, as well as, their vapour pressure as the function of temperature and composition
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Engstrom, Allison Michelle. "Vanadium Oxide Electrochemical Capacitors| An Investigation into Aqueous Capacitive Degradation, Alternate Electrolyte-Solvent Systems, Whole Cell Performance and Graphene Oxide Composite Electrodes." Thesis, University of California, Berkeley, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3616666.
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Vanadium oxide has emerged as a potential electrochemical capacitor material due to its attractive pseudocapacitive performance; however, it is known to suffer from capacitive degradation upon sustained cycling. In this work, the electrochemical cycling behavior of anodically electrodeposited vanadium oxide films with various surface treatments in aqueous solutions is investigated at different pH. Quantitative compositional analysis and morphological studies provide additional insight into the mechanism responsible for capacitive degradation. Furthermore, the capacitance and impedance behavior of vanadium oxide electrochemical capacitor electrodes is compared for both aqueous and nonaqueous electrolyte-solvent systems. Alkali metal chloride and bromide electrolytes were studied in aqueous systems, and nonaqueous systems containing alkali metal bromides were studied in polar aprotic propylene carbonate (PC) or dimethyl sulfoxide (DMSO) solvents. The preferred aqueous and nonaqueous systems identified in the half-cell studies were utilized in symmetric vanadium oxide whole-cells. An aqueous system utilizing a 3.0 M NaCl electrolyte at pH 3.0 exhibited an excellent 96% capacitance retention over 3000 cycles at 10 mV s-1. An equivalent system tested at 500 mV s-1 displayed an increase in capacitance over the first several thousands of cycles, and eventually stabilized over 50,000 cycles. Electrodes cycled in nonaqueous 1.0 M LiBr in PC exhibited mostly non-capacitive charge-storage, and electrodes cycled in LiBr-DMSO exhibited a gradual capacitive decay over 10,000 cycles at 500 mV s-1. Morphological and compositional analyses, as well as electrochemical impedance modeling, provide additional insight into the cause of the cycing behavior. Lastly, reduced graphene oxide and vanadium oxide nanowire composites have been successfully synthesized using electrophoretic deposition for electrochemical capacitor electrodes. The composite material was found to perform with a higher capacitance than electrodes containing only vanadium oxide nanowires by a factor of 4.0 at 10 mV s-1 and 7.5 at 500 mV s-1. The thermally reduced composite material was examined in both symmetric and asymmetric whole cell electrochemical capacitor devices, and although the asymmetric cell achieved both higher energy and power density, the symmetric cell retained a higher capacitance over 50,000 cycles at 200 mV s-1.
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Boisset, Aurelien. "Electrolytes pour supercondensateurs asymétriques à base de MnO2." Thesis, Tours, 2014. http://www.theses.fr/2014TOUR4038/document.
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Cette thèse a pour but de caractériser le fonctionnement de supercondensateurs asymétriques composés de dioxyde de manganèse de structure birnessite et de carbone activé dans différents électrolytes. Les électrolytes aqueux neutres à base de sels inorganiques montrent les meilleures performances électrochimiques. La nature et la structure des cations et des anions du sel semblent impacter les performances électrochimiques et la stabilité de la structure du matériau d’oxyde de manganèse. Lors de cyclage en milieu aqueux avec de large de fenêtre de tension de fonctionnement appliquée, un mécanisme de dégradation du dispositif a été avancé tenant compte de la nature des anions ou des cations des sels utilisés. Quelques voies de modification du matériau MnO2, afin d’améliorer ces performances électrochimiques, ont été étudiés. Des électrolytes non aqueux originaux ont été également caractérisés et plus particulièrement, les solvants « Deep Eutectic » à base de N-méthylacétamide et de sels de Lithium. Ces derniers semblent prometteurs comme électrolytes pour des applications en température sur carbone activé ou matériaux d’insertion tels que le ferrophosphate de lithium. Cependant ils semblent non adaptés aux oxydes de manganèse, mais donnent de bons résultats en cyclage avec le carbone activéThe aim of this thesis was to investigate the performances of asymmetric supercapacitors based on manganese dioxide (birnessite) and activated carbon electrode materials using various electrolytes. From this work, it appears that neutral aqueous electrolytes containing inorganic salts have the best electrochemical performances. Furthermore, the nature and the structure of both ions (cations and anions) in solution seem to impact strongly the electrochemical performances of the supercapacitors, as well as, the MnO2’s structure stability and affinity. In the case of aqueous-based electrolyte, a device degradation mechanism has been proposed as a function of salt ions structure and nature to further understand the supercapacitor’s life-cycling when a large potential window is applied. Some novel synthesis ways and/or modifications were investigated to further improve the electrochemical properties of MnO2 material. Additionaly, original non-aqueous electrolytes has been also formulated and then characterized, particularly the ‘Deep Eutectic’ Solvents, based on the N-methylacetamide mixed with a lithium salt. However, these electrolytes don’t have a good affinity with manganese oxide-based materials. Interestingly, these Deep Eutectic Solvents show good cycling results with activated carbon. In fact, these electrolytes seem to be promising for high temperature energy storage applications, especially using activated carbon or insertion electrode material like the lithium ferrophosphate
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Perricone, Emmanuelle. "Mise au point d'electrolytes innovants et performants pour supercondensateurs." Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00630049.
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L'objectif de cette thèse est de développer et d'optimiser un électrolyte organique performant et sécuritaire pour supercondensateur. En effet, l'acétonitrile est un solvant couramment employé dans la conception des électrolytes, mais celui-ci étant inflammable, il faut lui trouver une alternative performante. Différentes familles de solvants ont été évaluées. Les solvants stables d'un point de vue électrochimique ont été sélectionnés en vue de leur utilisation dans des électrolytes. Dans le but de trouver un compromis entre mobilité et concentration ionique, des mélanges de solvants ont été réalisés. L'addition de solvants peu visqueux comme des esters ou le méthoxypropionitrile dans l'éthylène carbonate et le sulfolane ont permis d'obtenir des électrolytes performants. L'étude des interactions solvant / solvant et solvant / sel ont été menées par des mesures calorimétriques, viscosimétriques et spectroscopiques. Ces interactions, bien que de très faible amplitude, permettent d'augmenter notablement la température d'évaporation du solvant volatil de l'électrolyte, donc son point éclair.
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Yao, N'guessan Alfred. "Contribution a l'etude des jonctions gaas-electrolyte aqueux et non aqueux : formation de l'interface et cinetique de transfert de charges." Paris 7, 1987. http://www.theses.fr/1987PA077174.
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Benzakour, Bouchra. "Ultramicroélectrochimie analytique : étude des phénomènes de transport de matière lors des réactions électrochimiques : application aux réactions engageant des étapes successives." Nancy 1, 1993. http://www.theses.fr/1993NAN10004.
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Les techniques ultramicroélectrochimiques engageant des électrodes de très faibles dimensions ont été appliquées à l'étude des phénomènes de transport de matière en absence d'électrolyte support lors des réactions électrochimiques. L'analyse des effets de migration a porté d'abord sur des transformations électrochimiques engageant une seule étape. Le comportement des systèmes i-/i#3#, br#/br#3#, br#/br#2 et le système du diphenylpicrylhydrazyle dpph-/dpph dans les solvants organiques a été précisé. La variation des courants limites en présence ou absence d'électrolyte a pu être quantifiée simplement. L'analyse a été étendue à des systèmes engageant plusieurs etapes, les uns faisant intervenir des espèces chargées (i#/i#3#/i#2, br#/br#3#/br#2, br#/br#2/br#+ et dpph#/dpph/dpph#+), les autres faisant intervenir des espèces moléculaires (la réduction du tetracyanoquinodimethane (tcnq), l'oxydation de la tetramethyl-p-phenylenediamine (tmppd) et la réduction de l'iode). Les effets d'exaltation sont également prévisibles à partir du modèle proposé
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Dubois, Corinne. "Sur les proprietes des couches de surface du lithium dans les accumulateurs a electrolytes organiques aprotiques." Paris 6, 1987. http://www.theses.fr/1987PA066345.
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Flake, John Christopher. "Photoelectrochemical etching of silicon in nonaqeous electrolytes." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/13278.
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Ivol, Flavien. "Formulation d'électrolytes sécuritaires pour supercondensateurs." Thesis, Tours, 2019. http://www.theses.fr/2019TOUR4020.
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L’objectif de cette thèse est de développer et d’optimiser un électrolyte organique performant et sécuritaire pour des supercondensateurs capacitifs. En effet, l’électrolyte aujourd’hui utilisé dans ces systèmes, présente des risques d’inflammabilité importants. Dans le cadre de cette thèse plusieurs solvants nitriles et dinitriles ont été utilisés pour la formulation d’électrolytes alternatifs pour les supercondensateurs. Ces solvants sont choisis pour leur grande stabilité thermique et faible volatilité. Par ailleurs, il a été proposé de remplacer le sel d’électrolyte de référence par des liquides ioniques aprotiques commerciaux ou issus de synthèses en laboratoire. En effet, la forte miscibilité et compatibilité des liquides ioniques avec les solvants choisis permet la formulation d’électrolyte fortement concentrés en ions favorisant ainsi le processus de stockage à la double-couche électrochimique. En outre, ces nouvelles formulations présentent un domaine liquide bien plus étendu que les formulations utilisant le sel de référence. Plus important encore, les travaux exposés dans ce manuscrit présentent une démarche expérimentale multiparamétrique s’appuyant parfois sur des modèles mathématiques et prédictifs pour aboutir à des formulations d’électrolytes optimiséesThe main objective of this PhD thesis is to design and optimize an efficient and safe organic electrolyte for capacitive supercapacitor applications. The benchmark electrolyte currently used in these particular systems presents a significant safety drawback, due to its high flammability. To overcome this issue, several nitrile and dinitrile solvents have been used to formulate alternative electrolytes for supercapacitors. These solvents were initially identified based on their relatively high thermal stability and low volatility. Furthermore, it was also proposed to substitute the reference molten salt with commercially available aprotic ionic liquids, or ones synthetized in the laboratory. The substitution was found to enhance the salt miscibility and compatibility when combined with selected organic solvents, allowing for the formulation of highly concentrated electrolytes with improved electric double-layer storage process. In addition, the ionic liquid-based electrolytes have a larger liquidus temperature range than that of the benchmark molten salt. More importantly, this work presents a clear strategy led by a multi-parametric experimental approach supported by theoretical calculations to optimize the formulation of safer electrolytes for supercapacitors
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Evans, Russell Griffith. "Application of room temperature ionic liquids as electrochemical solvents." Thesis, University of Oxford, 2005. http://ora.ox.ac.uk/objects/uuid:3b09fc8a-d3b0-47ff-8c6e-adaa79a3df1e.
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This thesis is concerned with investigating the suitability of room temperature ionic liquids as solvents in which to perform voltammetry, and in characterising electrochemical processes within these media. After providing a general introduction and a background to the ionic liquid field, the results of six original studies are presented, dealing in turn with the following subjects: • The oxidation of N,N,N',N'-tetraalkyl-para-phenylenediamine (TAPD) in five ionic liquids each incorporating the bis(trifluoromethylsulfonyl)imide anion. • The reduction of oxygen in four ionic liquids based on quaternary alkyl -onium cations and heavily fluorinated anions in which the central ion is either nitrogen or phosphorous. The simulation of double potential step chronoamperometry at a disk electrode for the case of unequal diffusion coefficients and its experimental validation using a variety of aqueous, traditional nonaqueous and ionic liquid solutions. • The rate of diffusion of N,N,N',N'-tetramethyl-para-phenylenediamme (TMPD), its radical cation and dication as a function of temperature and ionic liquid viscosity and four such solvents. • The temperature dependence of the viscosity of five ionic liquids along with the translational and rotational diffusion coefficients of dissolved 2,2,6,6- tetramethylpiperidine-N-oxyl (TEMPO). • The kinetics of the reaction between N,N-dimethyl-para-toluidine (DMT) and its electrogenerated radical cation in an ionic liquid solvent. The experimental strategy common to each report involves the application of cyclic voltammetry and chronoamperometry at disk electrodes immersed in uL-samples of ionic liquid solution. The data so measured is then analysed via the appropriate theoretical equations or, as is commonly necessary, by comparison with simulated voltammetry. Combined, these chosen redox systems provide access to information on various aspects of electrochemistry within ionic liquids, specifically (a) mass transport (b) the nature of the electron transfer process and (c) the rate of follow-up homogeneous reactions. It is the overall finding herein that while both diffusion and heterogeneous electron transfer are significantly slowed relative to the same processes in a conventional organic solvent, the rate of subsequent homogeneous chemistry remains largely unchanged.
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Adami, Fatos. "Analyse infra-rouge in-situ de l'interface electrode metallique/solution par la methode mirftirs : mise au point et application de la technique a l'etude de l'electropolymerisation des phenols sur electrode de fer." Paris 7, 1987. http://www.theses.fr/1987PA077042.
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Dong, Wei. "Contribution a l'etude theorique de la structure d'un fluide polaire et d'une solution electrolytique au voisinage d'une surface solide." Paris 6, 1987. http://www.theses.fr/1987PA066340.
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Modelisation de la solution par un melange de spheres dures chargees de meme taille et de la surface solide par une paroi dure de constante dielectrique unite. Resolution des equations integrales couplees associees au modele de la chaine hyperreticulee de reference (rhnc). Bonne description du profil densite-orientation pour un fluide dipolaire pur et accord avec les calculs par la methode de monte carlo. Construction d'une fonctionelle de densite pour decrire les effets orientationnels. Mise en evidence de deux effets importants dans le profil ionique: un effet de densite du a la granularite du solvant et un effet de force image repulsive engendre par la discontinuite dielectrique a la surface, avec appauvrissement en ions au voisinage de la surface. Analyse detaillee de la theorie du couplage faible appliquee a un melange d'ions et de dipoles ponctuels: certains diagrammes de type "bridge" contribuent au comportement asymptotique du profil ionique loin de la surface et permettent de reconcilier les resultats de la theorie microscopique avec ceux de l'electrostatique des milieux continus
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Gabouze, Noureddine. "Etude photoelectrochimique de gaas(n) et si(n) en milieu non aqueux ch::(3)oh et ch::(3)cn : etude et realisation de cellules photoelectrochimiques minces." Paris 6, 1988. http://www.theses.fr/1988PA066242.
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L'etude electrochimique et photoelectrochimique des jonctions semiconducteur-electrolyte non aqueux (ch::(3)oh et ch::(3)cn) de gaas et si permet de mettre en evidence les proprietes de surface de ces materiaux. Realisations des cellules minces (pec), gaas(ch::(3)oh)sno::(2) montrent des rendements de conversion de l'ordre de 12 a 13%
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Serre, Christophe. "Contribution à l'étude des mécanismes responsables de la dissolution anodique du silicium en milieu acide fluorhydrique aqueux." Grenoble 1, 1992. http://www.theses.fr/1992GRE10189.
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Ce travail est consacre a l'etude de la dissolution electrochimique du silicium monocristallin en milieu acide fluorhydrique. Dans une premiere partie bibliographique, nous decrivons l'interface silicium/acide fluorhydrique et les differents regimes de dissolution anodique: suivant les conditions d'anodisation, la dissolution peut se produire de maniere localisee (silicium poreux) ou homogene (electropolissage). Nous rappelons ensuite les mecanismes proposes dans la litterature, qui sont extremement complexes et restent tres mal connus. Nous presentons en deuxieme partie une etude de l'influence de la composition de l'electrolyte et de l'influence du regime hydrodynamique sur les caracteristiques courant-tension. Cette etude, rendue possible grace a une electrode tournante et une methode de mesure de ph fiable, a permis de montrer le role preponderant mais indirect de l'espece non dissociee hf, et nous a amene a suspecter la formation d'une couche d'oxyde a la surface de l'electrode en cours d'electropolissage. Dans une troisieme partie, nous avons mene une etude originale et detaillee basee sur un phenomene de courant transitoire qui apparait a la fin de la dissolution sous faible polarisation des oxydes en milieu hf. Les resultats obtenus, appliques a l'etude de la couche d'electropolissage, nous ont alors permis de confirmer que l'on avait tres vraisemblablement affaire a un oxyde, et la vitesse de dissolution de cette couche. Nous avons enfin propose un mecanisme de dissolution mettant en jeu une competition entre la croissance electrochimique de l'oxyde et sa dissolution chimique par hf
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Pelikán, Ondřej. "Elektrolyty s obsahem retardéru hoření na bázi fosforu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2018. http://www.nusl.cz/ntk/nusl-377067.
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The diploma thesis is focused on the theoretical knowledge of lithium accumulators. More attention is given to electrolytes and especially to flame retardants, where the types and individual examples of flame retardants are described more detailed. The practical part is focused on the individual laboratory measurement of selected samples of electrolytes with different flame retardants. The measurement results are analyzed in other parts.
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Štulák, Stanislav. "Stanovení bodu tuhnutí elektrolytů s retardérem hoření kryoskopickou metodou." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2014. http://www.nusl.cz/ntk/nusl-221001.
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The thesis is devoted to the field of properties investigation of new types of electrolytes, and assess the appropriateness of electrolytes studied in this paper for use in Li -ion batteries. It focuses specifically on electrolytes based on aprotic solvents and their mixtures with the flame retardants. The goal of the thesis is to investigate the effects of FRAs on electrolyte mixtures via changes in specific conductivity and freezing point. These objectives were fulfilled by using electrochemical impedance spectroscopy in combination with a cryoscopic measurement method. There were overall 16 samples examined. The samples were prepared as a combination of chemicals, specifically Ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), dimethyl sulfone (DMSO2), triethyl phosphate (TEP) Dimethyl methylphosphonate (DMMP), triphenyl phosphate (TPP). Based on the results of the experiments, the mixtures were sorted according to the observed properties in the tables listed in the last part of this paper. These values can be further used to supplement the continuing research of electrolytes and also as assistance in searching for the new electrolyte mixtures.
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Ahmed, Saifuddin. "Modélisation thermodynamique des mélanges électrolytiques multi-solvants pour les simulateurs de procédés." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS002/document.
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Les performances des modèles thermodynamiques actuels pour les solvants mixtes (en particulier avec alcools) électrolytiques sont limités. L’objectif de ce travail est d’étendre les capacités du modèle eGC-PPC-SAFT à ces systèmes. Ceci est fait en plusieurs étapes. Dans une première étape, le modèle PPC-SAFT existant est amélioré pour l’eau pure et les solvants usuels, par (1) introduisant une dépendance en température du diamètre sphère dure de l'eau et (2) adapter un minimum de paramètres ioniques sur les coefficients d’activité moyens et les densités des systèmes contenant des électrolytes forts ainsi que les sur les équilibres liquide vapeur des solvants mixtes d'électrolytes. Dans une troisième étape, le modèle final est utilisé pour représenter les équilibres liquide-liquide des solvants mixtes électrolytiques en étudiant les coefficients de partition de chacune des espèces dans le système. Pour cela, une stratégie de paramétrage des paramètres binaires ion-solvant a été développée, qui implique l’évaluation de l’impact de chacune des contributions individuelles du modèle ePPC-SAFT sur les coefficients de partition. Étant donné son importance dans le cadre de la modélisation thermodynamique de ces systèmes, une nouvelle règle de mélange pour le constant diélectrique est proposée. Au final, le modèle développé est capable de décrire les coefficients d’activité ainsi que les équilibres VLE et LLE des système électrolytiques avec solvants mixtesThe capabilities of the current thermodynamic models are limited in dealing with mixed-solvent electrolyte systems, due to the complex interactions within these systems. The objective of this work is to extend eGC-PPC-SAFT model to these systems. This is done in several steps. First, a modification in the temperature dependent water diameter was proposed. Second, a minimum number of ion-water parameters are determined on mean ioninc activity coefficients and densities of strong electrolyte systems, as well as vapour-liquid equilibria (VLE) of mixed solvent electrolytes. In the third step, the model is used to study the liquid-liquid equilibrium (LLE) of the mixed-solvent electrolyte system. This was done by looking at the partition coefficients of the individual species in the systems. In doing so, a parameterization strategy was developed for ion-solvent binaries that involve assessing the impact of the individual ePPC-SAFT contribution on the partitioning of individual species. A new method for dealing with the condition of electroneutrality in liquid-liquid ionic systems was proposed that involves a direct correction on the fugacity coefficient. In view of the importance of this property, a new mixing rule for the dielectric constant of mixed solvent is proposed to provide the best description of LLE of mixed solvent electrolyte. The final model is capable of describing, the activity coefficient, VLE, and LLE of mixed-solvent electrolyte systems
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子揚, 曹., and Ziyang Cao. "Dilution effects of highly concentrated electrolyte with fluorinated solvents on charge/discharge characteristics of Ni-rich layered oxide positive electrode." Thesis, https://doors.doshisha.ac.jp/opac/opac_link/bibid/BB13127443/?lang=0, 2020. https://doors.doshisha.ac.jp/opac/opac_link/bibid/BB13127443/?lang=0.
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高ニッケル三元系材料は商用のLiCoO2正極より高い容量を有するため、EVsで使用するリチウムイオン電池の正極材料の候補として有望である。本論文に、著者は濃厚電解液とフッ素化溶媒を用いた希釈電解液に着目し、高ニッケル三元系LiNi0.8Co0.1Mn0.1O2(NCM811)の充放電サイクル特性を向上させた。電解液中の溶媒化構造の観点から、濃厚電解液の希釈効果がNCM811の充放電特性に及ぼす影響を詳細に検討した。Ni-rich ternary materials have higher capacity than the commercial LiCoO2 positive electrode, and therefore they are promising candidates for the positive electrode material of lithium ion batteries for use in EVs. In this thesis, the author focused on highly concentrated electrolytes and their diluted electrolytes with fluorinated solvents to improve the cycling performance of a Ni-rich ternary LiNi0.8Co0.1Mn0.1O2 (NCM811) for practical application. Dilution effects of the concentrated electrolytes on the charge/discharge properties of NCM811 were discussed in detail from the viewpoint of the solvation structure in the electrolyte.
博士(工学)
Doctor of Philosophy in Engineering
同志社大学
Doshisha University
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Shen, Dai. "Investigation of Charge Transfer Kinetics in Non–Aqueous Electrolytes Using Voltammetric Techniques and Mathematical Modeling." Case Western Reserve University School of Graduate Studies / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case1574762430962913.
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Guha, Thakurta Soma. "Anhydrous State Proton and Lithium Ion Conducting Solid Polymer Electrolytes Based on Sulfonated Bisphenol-A-Poly(Arylene Ethers)." University of Akron / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=akron1239911460.
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Müller, Simon [Verfasser]. "Application and refinement of COSMO-RS-ES for calculating phase equilibria of electrolyte systems at high concentrations in mixed and non-aqueous solvents / Simon Müller." Hamburg : Universitätsbibliothek der Technischen Universität Hamburg-Harburg, 2020. http://d-nb.info/1222589095/34.
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Guibert, Sylvie. "Contribution a l'elaboration et a l'etude de nouveaux solvants organiques et electrolytes-supports utilisables dans les generateurs rechargeables au lithium." Rennes 1, 1987. http://www.theses.fr/1987REN10132.
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Blanchon, Le Bouhelec-Tribouillois Émilie. "Contribution à la thermodynamique de l'absorption des gaz acides H2S et CO2 dans les solvants eau-alcanolamine-méthanol : mesures expérimentales et modélisation." Thesis, Vandoeuvre-les-Nancy, INPL, 2006. http://www.theses.fr/2006INPL046N/document.
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Ce travail s'inscrit dans le cadre du développement de nouveaux procédés de désacidification de gaz naturel à travers l'étude thermodynamique des équilibres entre les gaz acides (CO2 et H2S) et un solvant mixte. Ce solvant résulte de la combinaison d'un solvant chimique (solution aqueuse de diéthanolamine) et d'un solvant physique (méthanol). Couplant équilibres chimique et physique, la modélisation de ces systèmes nécessite l'élaboration de modèles complexes et une large gamme de données d'équilibre liquide-vapeur. La première partie de ce travail est consacrée à l'acquisition de données expérimentales de solubilité des gaz acides dans le solvant mixte. En étendant le champ d'application d'un appareillage fonctionnant en méthode synthétique, nous avons acquis des données originales de solubilité des mélanges CO2 + H2S dans des solvants eau-diéthanolamine-méthanol. Dans la seconde partie, la modélisation simultanée des équilibres chimiques et physiques est réalisée. L'approche hétérogène développée combine le modèle NRTL-Electrolyte pour représenter la phase liquide avec l'équation d'état de Peng-Robinson pour décrire le comportement de la phase vapeur. La procédure d'ajustement des paramètres est graduelle si bien que le système complet eau-diéthanolamine-méthanol-CO2-H2S est décrit de manière prédictive, les paramètres du modèle NRTL-Electrolyte ayant été déterminés sur des systèmes inférieurs. L'effet de solvatation du méthanol est aussi mis en valeur. Nous nous sommes également intéressés au calcul des chaleurs d'absorption et à l'extension de notre modèle à d'autres alcanolaminesThis work is related to the development of new processes about gas sweetening with hybrid solvents coupling a chemical one (aqueous solution of diethanolamine) with a physical one (methanol). In the liquid phase, CO2 and H2S react with diethanolamine so that the VLE description of these systems is quite complex and requires experimental data. The first part of this work is dedicated to the experimental determination of acid gases + hybrid solvent solubility data. The experimental apparatus was improved to study H2S solubility and CO2 + H2S mixtures solubility in water-diethanolamine-methanol solvents. In the second part, the simultaneous representation of chemical and phase equilibria was realised. The heterogeneous approach developed here combines the Peng-Robinson equation of state for the vapour phase with the Electrolyte-NRTL model for the liquid phase. Parameters are fitted gradually so that the entire system water-diethanolamine-methanol-CO2-H2S system is extrapolated using Electrolyte-NRTL parameters determined by fitting experimental acid gas partial pressures of lower systems. Methanol effect is also described. An original calculation of heat of absorption was also developed. We extended the use of our approach to study others alkanolamines
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Thakore, Vaibhav. "Nonlinear dynamic modeling, simulation and characterization of the mesoscale neuron-electrode interface." Doctoral diss., University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5529.
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Extracellular neuroelectronic interfacing has important applications in the fields of neural prosthetics, biological computation and whole-cell biosensing for drug screening and toxin detection. While the field of neuroelectronic interfacing holds great promise, the recording of high-fidelity signals from extracellular devices has long suffered from the problem of low signal-to-noise ratios and changes in signal shapes due to the presence of highly dispersive dielectric medium in the neuron-microelectrode cleft. This has made it difficult to correlate the extracellularly recorded signals with the intracellular signals recorded using conventional patch-clamp electrophysiology. For bringing about an improvement in the signal-to-noise ratio of the signals recorded on the extracellular microelectrodes and to explore strategies for engineering the neuron-electrode interface there exists a need to model, simulate and characterize the cell-sensor interface to better understand the mechanism of signal transduction across the interface. Efforts to date for modeling the neuron-electrode interface have primarily focused on the use of point or area contact linear equivalent circuit models for a description of the interface with an assumption of passive linearity for the dynamics of the interfacial medium in the cell-electrode cleft. In this dissertation, results are presented from a nonlinear dynamic characterization of the neuroelectronic junction based on Volterra-Wiener modeling which showed that the process of signal transduction at the interface may have nonlinear contributions from the interfacial medium. An optimization based study of linear equivalent circuit models for representing signals recorded at the neuron-electrode interface subsequently proved conclusively that the process of signal transduction across the interface is indeed nonlinear. Following this a theoretical framework for the extraction of the complex nonlinear material parameters of the interfacial medium like the dielectric permittivity, conductivity and diffusivity tensors based on dynamic nonlinear Volterra-Wiener modeling was developed. Within this framework, the use of Gaussian bandlimited white noise for nonlinear impedance spectroscopy was shown to offer considerable advantages over the use of sinusoidal inputs for nonlinear harmonic analysis currently employed in impedance characterization of nonlinear electrochemical systems. Signal transduction at the neuron-microelectrode interface is mediated by the interfacial medium confined to a thin cleft with thickness on the scale of 20-110 nm giving rise to Knudsen numbers (ratio of mean free path to characteristic system length) in the range of 0.015 and 0.003 for ionic electrodiffusion. At these Knudsen numbers, the continuum assumptions made in the use of Poisson-Nernst-Planck system of equations for modeling ionic electrodiffusion are not valid. Therefore, a lattice Boltzmann method (LBM) based multiphysics solver suitable for modeling ionic electrodiffusion at the mesoscale neuron-microelectrode interface was developed. Additionally, a molecular speed dependent relaxation time was proposed for use in the lattice Boltzmann equation. Such a relaxation time holds promise for enhancing the numerical stability of lattice Boltzmann algorithms as it helped recover a physically correct description of microscopic phenomena related to particle collisions governed by their local density on the lattice. Next, using this multiphysics solver simulations were carried out for the charge relaxation dynamics of an electrolytic nanocapacitor with the intention of ultimately employing it for a simulation of the capacitive coupling between the neuron and the planar microelectrode on a microelectrode array (MEA). Simulations of the charge relaxation dynamics for a step potential applied at t = 0 to the capacitor electrodes were carried out for varying conditions of electric double layer (EDL) overlap, solvent viscosity, electrode spacing and ratio of cation to anion diffusivity. For a large EDL overlap, an anomalous plasma-like collective behavior of oscillating ions at a frequency much lower than the plasma frequency of the electrolyte was observed and as such it appears to be purely an effect of nanoscale confinement. Results from these simulations are then discussed in the context of the dynamics of the interfacial medium in the neuron-microelectrode cleft. In conclusion, a synergistic approach to engineering the neuron-microelectrode interface is outlined through a use of the nonlinear dynamic modeling, simulation and characterization tools developed as part of this dissertation research.Ph.D.
Doctorate
Physics
Sciences
Physics
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Bernhard, Rebecca Juliane [Verfasser], Hubert A. [Akademischer Betreuer] Gasteiger, and Bernhard [Akademischer Betreuer] Rieger. "Novel Electrolyte Solvents and Additives for Lithium-Ion Batteries and Different Materials Degradation Phenomena / Rebecca Juliane Bernhard. Gutachter: Bernhard Rieger ; Hubert A. Gasteiger. Betreuer: Hubert A. Gasteiger." München : Universitätsbibliothek der TU München, 2014. http://d-nb.info/1059477270/34.
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Smortsova, Yevheniia. "Dye sensitized solar cells efficiency improvement : optimization of the electrolyte using ionic liquids/molecular solvents mixture and study of the photodynamic properties of organic indolinic derivative dyes." Thesis, Lille 1, 2018. http://www.theses.fr/2018LIL1R061/document.
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Parmi les énergies renouvelables, l’énergie solaire est la plus puissante. L’élément clé des DSSCs est le photosensibiliseur, par lequel la génération de photocourant est possible. L’autre élément important est l’électrolyte. Les liquides ioniques (Ils) sont utilisés en tant qu’électrolytes dans les DSSCs du fait de leurs propriétés chimiques: pression de vapeur basse, haute résistance thermique et chimique, polarité et phase modulables, etc. L’objectif de cette thèse est de comprendre les processus photophysiques dans les colorants dérivés d’indolines dans les solvants moléculaires (MS) et les mélanges IL/MS. L’influence du solvant sur les propriétés spectroscopiques de D131, D102, D149 and D205 est d’abord étudiée par spectroscopie stationnaire d’absorption et de fluorescence. Ensuite, la spectroscopie résolue en temps est employée pour étudier leur photophysique et sa dépendance au solvant. Ces expériences ont permis de démontrer l’influence des paramètres d'aptitude de donneur de liaison hydrogène et d'accepteur de liaison hydrogène des solvants. Le rôle majeur de la dynamique de solvatation dans la dynamique des états excités de ces colorants a été montré. Ce phénomène a été suivi dans les mélanges IL/MS en utilisant une sonde fluorescente classique, C153, et des techniques de fluorescence résolues en temps et de dynamique moléculaire. Les réponses de solvatation multi-régimes de ces mélanges sont dirigées par le renforcement de la liaison hydrogène entre la sonde et les composants des mélanges. Les résultats de cette these apportent beaucoup à la compréhension des processus photophysiques fondamentaux régissant les sensibiliseurs et les électrolytes dans les DSSCsAmong all the renewable energy sources, solar energy is the most powerful source far ahead wind or geothermal energies. The first key component of DSSCs is the photosensitizer. It is through this component that the most important steps of photocurrent generation are possible. On the other hand, ionic liquids (ILs) have been proposed as electrolyte for DSSCs due to their peculiar properties: low vapor pressure, high thermal and chemical robustness, tunability of polarity and phase behaviour etc. The objective of this thesis was to get an understanding of the photophysics in the indoline derivated dyes in molecular solvents (MS) and in the IL/MS mixtures. Firstly, the solvent dependence of the spectroscopic properties of D131, D102, D149 and D205 was studied by the steady-state UV-Vis absorption and fluorescence spectroscopy. Then, time-resolved spectroscopy was used to elucidate their photophysics and its solvent dependence. These experiments helped to discern the influence of the hydrogen bond donor and acceptor abilities of the solvent. The solvation dynamics was shown to play a major role in the excited state dynamics of these dyes. This process in IL/MS mixtures was elucidated using the classic fluorescent probe C153 by the means of time-resolved spectroscopy and MD simulations. The complex multi-regime solvation response in these systems was shown to be shaped by the strengthening of the hydrogen bonding between the probe and the mixture components. The results of this thesis work contribute to the fundamental understanding of the photodynamics of the sensitizer and the response of the electrolyte used in the DSSCs
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Nunes, de Oliveira Heitor Fernando [Verfasser], Roberto [Akademischer Betreuer] Rinaldi, and Martin [Akademischer Betreuer] Muhler. "Organic solutions of ionic liquids and aqueous solutions of electrolytes as solvents for cellulose chemistry / Heitor Fernando Nunes de Oliveira. Gutachter: Roberto Rinaldi ; Martin Muhler." Bochum : Ruhr-Universität Bochum, 2016. http://d-nb.info/1095884328/34.
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Delouis, Grace. "Modélisation QSPR de solvants d’intérêt technologique : les liquides ioniques et les électrolytes pour batteries Li-ion." Thesis, Strasbourg, 2017. http://www.theses.fr/2017STRAF035/document.
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Cette thèse a pour but de modéliser les liquides ioniques et les électrolytes pour batteries Li-ion. Nous avons développé des modèles SVR afin de prédire 9 propriétés d’intérêt pour ces solvants. Les modèles construits pour les liquides ioniques ont permis la détection de divers problèmes, et sont accessibles sur le site web du laboratoire : infochim.u-strasbg.fr/webserv/VSEngine.html. Les modèles construits pour les électrolytes ont permis la modélisation de candidats testés expérimentalement par nos collaborateurs. Le nombre de données étant limité pour ces solvants, nous avons également testé l’approche transductive par le biais de la TRR (Transductive Ridge Regression). Nous avons mis en place un protocole d’optimisation des paramètres de la méthode et appliqué la TRR aux solvants étudiés. Les résultats obtenus par la TRR sont légèrement meilleurs que ceux de la Régression Ridge, mais restent modestes si on veut éviter une détérioration accidentelle du modèleThis thesis is dedicated to the modelling of ionic liquids and electrolytes of Li-ion batteries. We developed several SVR models in order to predict 9 interesting properties of these solvents. The models built for the ionic liquids allowed us to detect several problems, and are freely available on the laboratory’s website: infochim.u-strasbg.fr/webserv/VSEngine.html. The models built for the electrolytes were used to model some candidates tested experimentally by our colleagues. As the amount of data is quite small for these solvents, we also tested the transductive approach with the help of the TRR (Transductive Ridge Regression). We have developed an optimization procedure for the method’s parameters, and applied the TRR to the studied solvents. The results obtained with the TRR are slightly better than of the Ridge Regression but stay modest if we want to avoid any accidental damage of the model
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Azzouzi, Fouad. "Etude électrochimique de dihalogénomethylène bis (phosphonate de diéthyle) : action de l'anion formé in situ sur divers électrophiles et étude électrochimique des halogénovinylphosphonates formés." Rouen, 1989. http://www.theses.fr/1989ROUES026.
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Archane, Anas. "Etude de l'absorption des gaz acides dans des solvants mixtes : développement d'une approche expérimentale originale et modélisation des données par une équation d'état d'électrolytes." Paris, ENMP, 2009. http://www.theses.fr/2009ENMP1599.
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Le but du présent travail est la caractérisation des équilibres chimiques et des ELV pour les systèmes CO2/Diethanolamine(DEA)/H2O/MeOH et CO2 /Diethanolamine (DEA)/H2O/ PEG400. L'effet de composition du solvant physique sur l'absorption du CO2 a été étudié en utilisant quatre compositions (de 0% à 30% en masse d'alcool avec une composition fixe - 30% - de DEA), les mesures étant réalisées à une température de 298,15K et à divers taux de charge en CO2 (de 0 à 0,9). Les mesures expérimentales réalisées concernaient à la fois des données de solubilité et des donnée de spéciation. Ainsi, L'effet de composition de MeOH a été étudié en utilisant le dispositif expérimental original déjà utilisé pour l'analyse des systèmes Eau-DEA-CO2 (Sidi-Boumedine, 2003). Pour le système avec PEG 400, un nouvel dispositif expérimental permettant d'écarter la limitation de pression du précédent dispositif a été développé. La base de données originale obtenue comprenant des nouvelles données de solubilité et de composition de la phase liquide a permis la modélisation du système CO2/DEA/H2O/CH3OH en utilisant une équation d'état d'électrolyte développée au laboratoire (Fürst, 1993) représentant ainsi les propriétés d'équilibre du système que la spéciation en phase liquideThe aim of this study is the characterisation of VLE and chemical equilibria for the systems CO2/Diethanolamine-(DEA)/H2O/MeOH and CO2/Diethanolamine-(DEA)/H2O/PEG400. The effect of physical solvent composition on CO2 absorption has been studied using four compositions (from 0% to 30wt% of alcohol with a fixed composition-30%- of DEA), the measurement being made at T=298. 15K and at various CO2 loading (0 to 0. 9). The experimental measures concerned a both solubility data and liquid phase analysis was obtained. The effect of MeOH composition has been studied using the original experimental device developed previously (Sidi-Boumedine, 2003). For the system with PEG 400, a new experimental device excluding the pressure limitation of the precedent experimental device was developed. The original data base obtained, including the new solubility data and the liquid phase composition, allows the modelling of the system CO2/DEA/H2O/MeOH using an electrolyte equation of state (Fürst, 1993) representing the equilibrium properties of the system and the liquid phase speciation
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Skoglund, Emil. "A NUMERICAL MODEL OF HEAT- AND MASS TRANSFER IN POLYMER ELECTROLYTE FUEL CELLS : A two-dimensional 1+1D approach to solve the steady-state temperature- and mass- distributions." Thesis, Mälardalens högskola, Framtidens energi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-55223.
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Methods of solving the steady state characteristics of a node matrix equation system over a polymer electrolyte fuel cell (PEFC) were evaluated. The most suitable method, referred to as the semi-implicit method, was set up in a MATLAB program. The model covers heat transfer due to thermal diffusion throughout the layers and due to thermal advection+diffusion in the gas channels. Included mass transport processes cover only transport of water vapor and consist of the same diffusion/advection schematics as the heat transfer processes. The mass transport processes are hence Fickian diffusion throughout all the layers and diffusion+advection in the gas channels. Data regarding all the relevant properties of the layer materials were gathered to simulate these heat- and mass transfer processes.Comparing the simulated temperature profiles obtained with the model to the temperature profiles of a previous work’s model, showed that the characteristics and behavior of the temperature profile are realistic. There were however differences between the results, but due to the number of unknown parameters in the previous work’s model it was not possible to draw conclusions regarding the accuracy of the model by comparing the results.Comparing the simulated water concentration profiles of the model and measured values, showed that the model produced concentration characteristics that for the most part alignedwell with the measurement data. The part of the fuel cell where the concentration profile did not match the measured data was the cathode side gas diffusion layer (GDL). This comparison was however performed with the assumption that relative humidity corresponds to liquid water concentration, and that this liquid water concentration is in the same range as the measured data. Because of this assumption it was not possible to determine the accuracy of the model.
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Bley, Michael. "Simulating Osmotic Equilibria by Molecular Dynamics - From Vapor-Liquid Interfaces to Thermodynamic Properties in Concentrated Solutions." Thesis, Montpellier, 2018. http://www.theses.fr/2018MONTS122.
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L’objectif de cette thèse de doctorat est le développement d’une nouvelle méthode théorique basée sur la simulation des équilibres liquide-gaz par simulations de dynamique moléculaire. Cette nouvelle m´méthode prédit les propriétés thermodynamiques telles que l’activité des solvants et les coefficients d’activité des solutés en phases aqueuses et organiques impliquées dans les systèmes d’extraction liquide-liquide. Ces propriétés thermodynamiques sont nécessaires pour les approches de modélisation thermodynamique mésoscopique permettant d’estimer l’efficacité et la s´électivité d’un système d’extraction par solvant jusqu’au une échelle industrielle. Les propriétés thermodynamiques et structurales des solutions électrolytiques aqueuses et des phases organiques, y compris les agrégats résultant des molécules d’extraction des amphiphiles, sont en bon accord avec les données expérimentales et théoriques disponibles. L’approche de dynamique moléculaire de l’équilibre osmotique fournit un nouvel outil puissant permettant d’accéder aux données thermodynamiquesThe aim of this PhD thesis is the development of a new theoretical method based on the simulation of vapor-liquid equilibria by means of molecular dynamics (MD) simulation. This new method predicts thermodynamic properties such as solvent activities and solute activity coefficients of aqueous and organic phases used in liquid-liquid extraction systems. These thermodynamic properties are required for mesoscopic thermodynamic modeling approaches estimating the efficiency and selectivity of a given solvent extraction system up to an industrial scale. Thermodynamic and structural properties of aqueous electrolyte solutions and organic solvent phase including aggregates resulting from amphiphilic extractant molecules are reproduced in very good agreement with previously available experimental and theoretical data. The osmotic equilibrium MD approach provides a new and powerful tool for accessing thermodynamic data
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Berhaut, Christopher Logan. "Propriétés de transport des sels de lithium LiTDI et LiFSI : application à la formulation d'électrolytes optimisés pour batteries Li-ion." Thesis, Tours, 2016. http://www.theses.fr/2016TOUR4017/document.
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La plupart des batteries Li-ion aujourd’hui utilisent des électrolytes à base de LiPF6 un sel de lithium connu pour son instabilité chimique au-delà de 60°C car il se dégrade en libérant PF5 et LiF. En présence de traces d’eau il génère en plus des composés oxyfluorophosphorés et du HF qui peut être dommageable à la fois pour les performances et pour le vieillissement de l’accumulateur. Plusieurs sels sont candidats au remplacement de LiPF6, notamment ceux basés sur les anions fluorosulfonylamidures et les anions de Hückel. Ce travail concerne l’étude des propriétés physico-chimiques et de transport des électrolytes à base de 4,5-dicyano-2- (trifluoromethyl)imidazolide de lithium (LiTDI) et bis(fluorosulfonyl)amidure de lithium (LiFSI) pour une utilisation au sein d’accumulateurs de type Li-ion. Dans ce travail il a d’abord été montré que LiTDI n’est que faiblement dissocié dans les mélanges de carbonates d’alkyles utilisés dans les batteries Li-ion tels que le binaire (EC/DMC) ce qui limite sa conductivité. Pour pouvoir remédier à cet inconvénient, une étude des phénomènes de solvatation et d’associations ioniques a été menée et a conduit à proposer un mélange ternaire de solvants (EC/GBL/MP) dans lequel LiTDI est plus dissocié. Le mélange ternaire proposé améliore à la fois les propriétés de transport et les caractéristiques thermiques de l’électrolyte sans compromettre le domaine de stabilité chimique et électrochimique. Enfin, le nouvel électrolyte EC/GBL/MP contenant LiTDI, a été testé en accumulateurs dans les conditions opératoires usuelles (régime C/10 et température ambiante) et sévères (régime 10C et des températures allant de -20 °C à 60 °C). Le problème de corrosion de l’aluminium de LiFSI a aussi été pris en compte. Un électrolyte prometteur à base d’un mélange LiTDI/LiFSI montrant de meilleures performances que chaque sel utilisé séparément dans EC/DMC a été présenté. Les conclusions de cette thèse prouvent que LiTDI ou LiFSI peuvent être utilisés comme sels de lithium dans les électrolytes pour accumulateurs Li-ionMost of the Li-ion batteries used in electrical devices contain a solution of LiPF6 in alkylcarbonate solvents with the risk of releasing PF5 at elevated temperatures and HF in the presence of water. Several salts are candidates for the replacement of LiPF6, including those based on fluorosulfonylamides and Hückel anions. This work concerns the study of physicochemical and transport properties of lithium 4,5-dicyano-2- (trifluoromethyl)imidazolide (LiTDI) and lithium bis(fluorosulfonyl)amide (LiFSI) based electrolytes and their use in Li-ion battery. First it was revealed that LiTDI is only weakly dissociated in alkylcarbonate mixtures used in Li-ion batteries such as EC/DMC limiting its conductivity. To overcome this disadvantage, a study of the solvation phenomena and of ionic association within the electrolytes was conducted. This study led to a ternary mixture of solvents (EC/GBL/MP) in which LiTDI is more dissociated. This new solvent mixture improves both the transport properties and the thermal stability of the LiTDI based electrolyte without compromising its chemical and electrochemical stability. Finally, the new LiTDI in EC/GBL/MP electrolyte was tested in NMC/graphite batteries under normal (C/10 rate and room temperature) and severe (10C rate and temperatures varying from - 20 ° C to 60 °C) operating conditions. The aluminium corrosion problem encountered by LiFSI based electrolytes was taken into account and a LiTDI/LiFSI salt mixture based electrolyte showing promising results was presented. The findings of this thesis show that LiTDI or LiFSI can be used as lithium salts in electrolytes for Li-ion batteries
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Coadou, Erwan. "Organosulphur compounds for electrochemical energy storage applications : supercapacitors and lithium-sulphur batteries." Thesis, Queen's University Belfast, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.706291.
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The work presented in this manuscript concentrates on investigating the use of organosulfur compounds as potential electrolyte components for electrochemical energy storage systems, in particular in lithium-sulfur batteries. Novel glyme-functionalised sulfonium-based ionic liquids were synthesized and characterised before being tested as pure electrolytes for symmetrical supercapacitors based on activated carbon electrodes. The adaptation of the structure of the ionic liquids to the porosity of activated carbon was found to be of fundamental importance for the design of more efficient systems. For lithium-sulfur batteries, the study has enabled a better understanding of the mechanisms involved during the operation of the sulfur/diphenyl disulfide redox couple in a range of glyme-based solvents. Similarly, the influence of the glyme-based solvents on the chemical equilibria between organic and mineral polysulfides and on the system operation has been investigated. The initial results demonstrated that this is a particularly promising strategy in order to significantly improve the performances of lithium-sulfur batteries.
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Dahbi, Mouad. "Etude d'électrolytes organiques pour la réalisation de supercondensateurs lithium-ion." Thesis, Tours, 2013. http://www.theses.fr/2013TOUR4031.
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Le travail réalisé dans cette thèse concerne l'optimisation d’électrolytes organiques pour supercondensateur lithium-ion. Plusieurs solvants ont été sélectionnés pour la formulation de mélanges binaires ou ternaires additionnés de sel de lithium. Les propriétés physicochimiques et électrochimiques de ces électrolytes contenant LiTFSI ou LiPF6 (EC/DMC ; dinitrile/DMC ; EC/Ester/3DMC, EC/MiPC/3DMC) ont été caractérisées en vue de leur utilisation dans des dispositifs hybrides, l’objectif étant de satisfaire à la fois aux exigences des matériaux graphite et carbone activé. Les interactions solvant-solvant et solvant-sel des électrolytes ont été étudiées à partir des théories de Jones-Dole, Stocks-Einstein et Bjerrum appliquées aux mesures de viscosités et conductivités. Cela a permis de développer des modèles prédictifs de la conductivité dans des cas de solvants purs ou de mélanges simples. La deuxième partie de cette thèse a été dédiée à la réalisation de demi-cellules avec différentes formulations d'électrolytes à la fois sur carbone activé et sur graphite. Les interfaces électrodes/électrolytes et séparateurs/électrolytes ont été étudiées. La corrosion des collecteurs en Al en présence de LiTFSI a fait l'objet d'une étude qui a permis de dégager une solution consistant en la formulation d'un électrolyte additionné de 1% d'additifs source de fluorure tel que LiPF6. Enfin, des dispositifs complets graphite/carbone activé ont été réalisés en utilisant les différents électrolytes optimisés ce qui a permis de mettre en évidence le gain en énergie (x5) pour un tel système par rapport aux supercondensateurs symétriques classiquesThe objective of this thesis is to broaden the knowledge of electrochemical, thermo physical and thermodynamic properties of different efficient and safe organic electrolytes for Lithium-ion Capacitors (LICs). Several solvent structures have been first selected to design new electrolytes based on binary or ternary solvent mixtures. These solvents were then characterized through conductivity, viscosity and electrochemical studies, in order to assess their structure and properties relationships. Based on this investigation, best compromise between mobility and ionic concentration has been evaluated to formulate the best electrolytes. Generally, it was proved that the addition of solvents with very low viscosity provides efficient electrolytes. Based on conductivity and viscosity measurements, a theoretical study on solvent-solvent and solvent-salt interactions has been then performed using different well-known equations based on Stock-Einstein, Jones-Dole and Bjerrum theories to understand, rationalize, correlate and then predict their transport properties. The second part of the study concentrated on the characterization of selected electrolytes in an asymmetric LIC prior to developing such electrolytes in any high performance asymmetric capacitor devices. In other words, the main objective of this part is to verify the compatibility of designed electrolytes with each element, e.g. electrodes (graphite, activated carbon) and current collectors (aluminum), of a LIC device. To drive such analysis, different experimental investigations between electrodes/electrolytes and between collectors/electolytes were in fact investigated. Using this strategy, asymmetric systems LICs containing a formulated organic electrolyte were fully characterized to deter mine the electrochemical performances of the designed solution in LIC conditions and then compared with those observed using classical electrolyte currently used
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Chrétien, Fabien. "Etude de l'effet des sels de lithium de la couche de passivation sur la cyclabilité d'un accumulateur lithium-ion." Thesis, Tours, 2015. http://www.theses.fr/2015TOUR4009/document.
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Limiter le vieillissement des accumulateurs lithium-ion est un challenge pour optimiser leur utilisation notamment dans le domaine spatial. La qualité de la couche de passivation (SEI), formée à la surface de l’électrode négative de graphite lors des premiers cycles de vie de la batterie, est déterminante pour ses performances futures. Celle-ci est composée de polymères et de divers sels de lithium dont la dissolution, la précipitation et la migration affectent les performances. Cette étude vise à comprendre l’impact de ces composés sur la cyclabilité et de proposer des solutions à l’effet néfaste de ces sels sur le bon fonctionnement et le vieillissement de l’accumulateur Li-ion. La première partie de ce travail aborde l’impact de divers sels de lithium de la SEI (LiF, Li2CO3, LiOH, LiOCH3, LiOC2H5) sur le comportement en cyclage des accumulateurs. Par la suite, nous avons proposé des solutions pour améliorer le comportement qu’engendre la présence de ces sels sur les performances à travers deux approches. La première concerne l’utilisation de co-solvants complexants de la famille des glymes. La seconde approche consiste à modifier les propriétés interfaciales électrodes/électrolyte par l’ajout d’additifs tensioactifs à l’électrolyte. Les résultats montrent dans les deux cas des améliorations notables de la cyclabilité des dispositifs en demi-pile et en cellule complèteLimiting the lithium-ion batteries ageing is a challenge to overcome in the field of spatial applications. The quality of the solid electrolyte interfaces (SEI), created at the electrode surface during the first cycles of the battery, is decisive for its future performances. The SEI is composed of polymers and several lithium salts which are able to dissolve, precipitate and migrate in the electrolyte and hence modify the battery performances. This study aims to understand the impact of the dissolution of these compounds on the cell cycling ability and to propose solutions to avoid the harmful effects of these salts on the battery ageing. The first part of this study is devoted to the study of the effect of dissolved SEI lithium salts (LiF, LiOH, Li2O, Li2CO3 , LiOCH3, LiOC2H5) on the cycling ability of half and full cells.In order to improve the battery performances in spite of the presence of these SEI salts in the electrolyte, two solutions have been examined. The first one is to add a co-solvent belonging to the glyme family which is able to form complexes with lithium ions and the second to use a surfactant additive which will modify the interfacial electrode/electrolyte properties. Results show that in both cases an improvement in half-cell or full-cell cycling ability was achieved
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Ah-Lung, Guillaume. "Mise au point et optimisation d'un procédé de synthèse chimique de MnO2 : application aux supercondensateurs aqueux." Thesis, Tours, 2019. http://www.theses.fr/2019TOUR4022.
Full textAbstract:
L’émergence d’applications nécessitant des densités d’énergie et de puissance toujours plus importantes tout en assurant une sécurité d’utilisation aux coûts les plus intéressants stimule la recherche de matériaux efficaces, simples à mettre en œuvre et respectueux de l’environnement et de la santé.Les travaux de cette thèse ont porté sur la synthèse d’oxydes de manganèse à la morphologie et la structure contrôlées pour la conception de supercondensateurs asymétriques en milieu aqueux s’inscrivant dans les politiques environnementales et industrielles actuelles. Une première étude des paramètres de synthèse par voie chimique des oxydes de manganèse nous a conduits à identifier le pH comme étant un facteur prédominant dans le contrôle de la morphologie et la structure des oxydes à température ambiante. L’association d’un solvant de haute viscosité et d’un pH élevé permet de synthétiser des oxydes de manganèse de type Birnessite, structure très intéressante pour des applications électrochimiques. Une étude approfondie, d’un point de vue physico-chimique et électrochimique, a permis de mettre en avant une forte corrélation entre les propriétés morphologiques, structurales et de texture de l’oxyde avec ses performances électrochimiques. Ainsi des capacitances spécifiques de 200 F.g-1 sont atteintes pour de tels matériaux. La conception de supercondensateurs asymétriques MnO2//Graphène en milieu aqueux génère des densités d’énergie et de puissance élevées (> 15 Wh.kg-1, > 2 kW.kg-1) par rapport à des dispositifs similaires décrits dans la littérature. En plus de ces travaux des études complémentaires sur les mécanismes de stockage des oxydes de manganèse ont été menées, il a également été montré qu’un dimensionnement de ces électrodes avec des masses de matériaux actifs relativement importantes (> 10 mg.cm-2) est possible sans affecter les performances. Une étude thermodynamique des électrolytes aqueux a démontré la possibilité de cycler à des températures de l’ordre de -20°C répondant alors à d’autres contraintesThe emergence of applications requiring increasingly high energy and power densities while ensuring safety utilization, at the most interesting costs stimulates the research of efficient, simple to implement, eco-friendly and non-hazardous materials.This thesis focuses on the synthesis of manganese oxides, with controlled-morphology and –structure as a positive electrode for asymmetric supercapacitors operating in aqueous electrolyte as part of the current environmental and industrial policies. An initial investigation of the synthesis parameters allowed us to identify the pH as a predominant parameter for controlling the oxide morphology and structure at room temperature. The combination of viscous solvent and basic pH led to crystalline Birnessite manganese oxide, attractive for electrochemical applications. A deep physicochemical and electrochemical study highlighted a strong correlation between the morphological, structural and textural properties with electrochemical performances. Thus, such materials exhibit capacitances around 200 F.g-1. The development of MnO2//Graphene asymmetric supercapacitors operating in aqueous electrolyte generate high energy and power densities (> 15 Wh.kg-1, > 2 kW.kg-1) compared to similar devices reported in literature. Moreover, further studies were performed to better understand the MnO2 storage mechanisms and demonstrated that an electrode sizing with a high loading (> 10 mg.cm-2) is possible, while maintaining interesting performances. A thermodynamic investigation of aqueous electrolytes highlights the cyclability of our devices at -20°C, giving a solution to other constraints
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Hsu, Shu-Ming, and 許書銘. "A Study on the Solubilities of Electrolyte Mixed Solvent Systems." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/43594507151211380247.
Full textAbstract:
碩士國立臺灣科技大學
化學工程系
88
The objective of this study is to investigate the solubility of salt in mixed solvent systems. In the experimental part, a gravimetric analysis apparatus was employed to measure the solubility at 298.15K for nine ternary systems of ethanol-water-NaCl, n-propanol-water-NaCl, i-propanol -water-NaCl,n-butanol-water-NaCl, methanol-water-NaBr, ethanol -water -NaBr, n-propanol-water-NaBr, i-propanol-water-NaBr, and n-butanol -water-NaBr. In the theoretical part, the Chen’s models(1982, 1986) were used to calculate the mean activity coefficients of electrolyte in both binary and ternary electrolyte solutions, respectively. A calculation scheme with Chen’s models is developed to determine the solubilities for the nine ternary systems mentioned above. It was found that the calculated results agree well with the experimental data, with mean absolute deviations ranging from 0.013 to 0.092 for the nine ternary systems studied.
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Wu, Ming-Song, and 吳明崧. "A Study on Liquid-Liquid Equilibria of Electrolyte Mixed Solvent Systems." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/45057761185665660469.
Full textAbstract:
碩士國立臺灣科技大學
化學工程系
87
The objective of this study is to investigate salt effects on liquid-liquid equilibria (LLE) in mixed solvent systems, including experimental measurements and theoretical predictions. For a temperature range of 15-35oC with an increment of 10oC, the experiments of LLE for binary systems of n-butanol(NBA)- water, iso-butanol(IBA)- water and sec-butanol(SBA)- water and that for ternary system of n-butanol(NBA)- water- NaCl were made and checked with literature data. At a single temperature of 25oC, the LLE data for ternary systems of n-butanol(NBA)- water- KCl, iso-butanol(IBA)- water- KCl and sec-butanol(SBA)- water- KCl were measured in this study. In theoretical simulation, the activity coefficients of solvents were calculated by Tan''s modified Wilson model, combined with vapor pressure model of electrolyte aqueous solutions. The Gibbs-Duhem equation was used to calculate mean activity coefficient of the electrolyte. Based on the scheme of flash calculation, the mole fractions in both phases were predicted without adding new adjustable parameter. It was found that the theoretical simulations for the six cases reported in this study were in good agreement with experimental data.
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Chih-AoLiao and 廖之敖. "Graphite anode surface redox reaction analysis and development of new electrolyte solvent molecules." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/v3hp28.
Full textAbstract:
碩士國立成功大學
材料科學及工程學系
107
By comparing graphite anode electron potential (Fermi level) and electrolytes’ electron affinity (EA), the tendency of electron transfer between electrode and electrolytes is revealed. The transfer has long been considered as the key mechanism to initiate SEI formation at the early stage of batteries charging. There is difficulty to compare the two energy levels due to different reference energy by different computational tools. The background charge, however, artificially change vacuum electrostatic potential resulting in incorrect work function, so as misalignment of fermi levels. To solve it, the fixed density of state assumption was adopted to estimate the Fermi level shifting due to add or extract additional charges. We calculated graphite armchair and zigzag surfaces with three conditions, pristine, hydrogen terminated and hydroxide terminated surfaces. DOS and work function are calculated to compare each surfaces Fermi level as respect to vacuum level. We finally found that the surfaces with hydrogen and hydroxide terminated surfaces have higher Fermi level as respect to pristine ones. Eelectrochemical stability window also shows that lithium ion solvated EC is the most reactive molecule in electrolytes that receive electron. To improve it, high-throughput modification and EA/IE prediction algorism is used for searching alterative molecules. Result shows that B-centered with 3 methoxy functional groups molecule has potential to be the alterative molecule due to the broaden electrochemical stability window and stable structure during redox reaction. Moreover, with low dipole moment and polarizability, we consider that B_methoxy molecule has potential to replace DEC.
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Yang, Cheng-Ta, and 楊政達. "Study of efficiency and stability of organic solvent/ionic liquid applications of electrolyte solvent on e Dye-Sensitized Solar Cells." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/11547917486585098789.
Full textAbstract:
碩士明志科技大學
化學工程研究所
99
The object of this research is to study the organic-solvent/ionic-liquid systems as electrolyte solvents for applications in dye-sensitized solar cells (DSSCs), and to observe the effects of viscosity and conductivity of the electrolytes on the cell efficiency and stability of DSSCs. Cells were fabricated from twenty electrolyte solvents together with light absorbing TiO2 electrode and Pt counter electrode. Cells’ current-voltage (IV) curves were measured and observed for 600 hrs. Organic solvents employed in this study were propylene carbonate (PC) and acetonitrile(AN) ; while ionic liquids include 1-butyl-3-methylimidazolium tetrafluoroborate (BMIBF4) and 1-N-butyl-3-metylimidazolium hexafluoro- phosphate (BMIPF6). Twenty electrolyte solvent systems were prepared by combinations of the above components. Experimental results showed that viscosity and conductivity of the electrolytes has direct effect on the efficiency of the cells. These results help to select proper electrolyte systems for applications on DSSCs. In general, desirable cell performance can be achieved by using mainly organic solvent in the electrolyte system; however, certain amount of ionic liquid helps to enhance cell stability. The results also showed that no matter BMIBF4 or BMIPF6 were employed, there was not obvious difference in the viscosity and conductivity of the electrolytes; cell efficiency and stability also remained almost the same. Detailed process of the cell assembly was also demonstrated in this study.
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Cheng, Cheng-Liang, and 鄭丞良. "Conductive Behavior of Lithium Ions in Polyacrylonitrile-based Gel Polymer Electrolyte Containing Non-solvent." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/81015026084299217310.
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Ming-CheYang and 楊明哲. "Fabrication of photovoltachromic cells using screen-printed tungsten oxide and solvent-free polymer electrolyte." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/80782337416117182646.
Full textAbstract:
碩士國立成功大學
化學工程學系碩博士班
101
Tungsten oxide films have been formed by screen-printed. First, peroxopolytungstic acid solution was mixed with a binder to form a slurry and printed on the FTO glass substrates. By the electrical measurement, tungsten oxide films show a good electrochromic properties. Afterward, this tungsten oxide film was applied to the photovoltachromic devices. To assemble the photovoltachromic devices combine screen-printed tungsten oxide/platinum composite electrode and N719 dye-sensitized titanium dioxide electrode. The solvent free polymer electrolyte was applied to photovoltachromic devices. By the adjustment of the electrolyte, the optical properties and the photoelectric conversion efficiency of the photovoltachromic devices were analyzed. Under illumination, the response time for coloring and bleaching the cell with short-circuited and open-circuited are 8 and 6s, respectively. In addition, it shows the response time for coloring and bleaching under illumination and dark are 8 and 81s. The cell’s photoelectric conversion efficiency was 0.28%, and the transmittance of the colored photovoltachromic devices was variable by adjusting the variable resistance in series with photovoltachromic devices.
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Tsai, Yueh-fu, and 蔡岳甫. "A Modified Setschenow Equation and its application for Liquid-Liquid Equilibria of Mixed Solvent-Electrolyte Systems." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/68217829903096885894.
Full textAbstract:
碩士國立臺灣科技大學
化學工程系
88
The objective of this study is to modified Setschenow equation to describe the salt effects on liquid-liquid equilibria (LLE) of mixed solvent systems. In experimental part, the experiments of LLE for binary systems of n-butanol- water, iso-butanol- water and sec-butanol- water and that for ternary system of n-butanol- water- NaCl were made and checked with literature data (De Santis, 1976). The LLE data for ternary systems of n-butanol- water- KCl, iso-butanol- water- KCl and sec-butanol- water- KCl were measured at a single temperature of 298.15K. In the theoretical simulation, the Setscheonw equation was modified and used to calculate the mole fraction of electrolyte in the aqueous phase. The activity coefficients of solvents in mixed solvent-electrolyte systems were calculated by the TTK-Wilson model. Based on the material balance in phase equilibria, the mole fractions in both phases were calculated by using two adjustable parameters. It was found that the theoretical simulations for the twelve systems reported in this study were in good agreement with experimental data. The mean deviation range from 0.004 to 0.015.
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Duignan, Timothy Thomas. "Modelling specific ion effects with the continuum solvent." Phd thesis, 2015. http://hdl.handle.net/1885/13642.
Full textAbstract:
Electrolyte solutions play a central role in many processes from industry to
biology. Understanding and building predictive models of their properties
has therefore been a fundamental goal of physical chemistry from its beginnings.
The challenge remains.
In this thesis I outline a continuum solvent model of univalent monatomic
ions in water. This model calculates the free energy of: 1) a single ion in
bulk, 2) of an ion approaching the air–water interface and 3) of two ions approaching
each other. Its central advancements are to include quantitatively
accurate ionic dispersion interaction energies, missing from classical theories,
including the higher order multipole moment contributions to these
interactions. It also includes the contribution from the cavity formation energy
consistently, including the effect of changes in the cavity’s shape. Lastly,
it uses a quantum mechanical treatment of the ions and provides satisfactory
values for their size parameters. Because one consistent framework is used
with the same assumptions to calculate the free energies in these three different
situations the number of parameters can be minimised and the model
can be properly tested.
These three calculations can be used to reproduce experimental solvation
free energies, solvation entropies, partial molar volumes, surface tensions
and activity/osmotic coefficients of the alkali-halide electrolyte solutions. A
minimum of parameters are used and crucially no salt–specific fitting parameters
are necessary. The model is quantitative and predictive and is therefore
a satisfactory model of electrolyte solutions.
It provides an explanation of several key qualitative puzzles regarding
these properties. Namely that ions of the same size can have different solvation
energies, that large ions can adsorb to the air–water interface and that
ions in solution that have similar solvation energies are more strongly attracted to each other than ions that have dissimilar solvation energies. The
continuum solvent model and separate ab initio calculations show that dispersion
interactions play a key role in controlling these effects. In particular,
dispersion energies explain the attraction of large ions for each other in water
and the difference in solvation energy of ions of the same size. The success
of the model implies that it is possible to understand the key properties of
electrolyte solutions using a continuum solvent model. This is an important
conclusion considering the massive computational demands of explicit solvent
treatments.
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林秀育. "Preparation and characterization of capacitor element of solidpolymer electrolyte of Ppy/Al2O3/Al- effect of dopant and solvent." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/30448085432589354164.
Full textAbstract:
碩士國立勤益技術學院
化工與材料工程系
93
This investigation is focus on the preparation of the polypyrrole composite films, Ppy/Al2O3/Al, used as solid-state capacitor with electrochemically polymerization in aqueous solution in the presence of various kinds of dopant and solvent. Further, factors that affected the characteristics of Ppy/Al2O3/Al were explored including the kind of dopant; concentration of dopant; the kind of solvent; ratio of organic solvent/volume of water; and the coulombs of electricity passed. Further, the durability testing of solid polymer electrolyte capacitor was loaded at a constant voltage situation and that was in situ also analyzed via AC impedance. From the experimental results revealed that the capacitance increased from 574.3 to 616.8 and the value of DF decreased from 39.93 to 18.53% in the presence of 0.1 M DBSA when the dopant concentration of 2-NSNa increased from 0 to 0.01 M. On the other hand, leakage current decreased from 0.0067 to 0.0056 when the dopant concentration of ammonium adiapate increased from 0 to 0.005 M in the presence of 0.1 M DBSA solution. In addition, the capacitance increased from 574.3 to 684.3 and DF decreased from 39.3 to 13.7 when the volume ratio of DMSO/water increased from 0 to 10 %. The performances of capacitor were also explored. Leakage current(Lc), capacitor(Cs), dicipation factor (DF) and equivalent series resistance(ESR), these parameters of the solid-state capacitor were measured. On the other hand, the surface morphologies and compositions of the prepared Ppy/ Al2O3 /Al electrolyte were examined with SEM and EDS, respectively. The increasing of the surface area of Al plate by etching process was detected by BET method. The optimum operating conditions using 2-NSNa as a dopant for this system were added 10% DMSO/H2O, 0.01M added 2-NSNa, 0.1 M added DBSA, and 3 coulombs of electricity passed. The performances of capacitor were Lc, Cs , DF , and ESR . In addition, the optimum operating conditions in the presence of 0.1 M DBSA and ammonium adiapate as dopants for this system were added 10 % DMSO/H2O, 0.05M added ammonium adiapate, and 4 coulombs of electricity passed. The performances of capacitor were Lc, Cs , DF , and ESR . The major resistances of the solid polymer electrolytic capacitors that were prepared by supplied 4.0 coulombs of electricity passed were contributed from the film of aluminum oxide, ( ) and the resistance of polypyrrole electrolyte ( ), while the solid polymer capacitor was analyzed via an AC impedance with a 4 V loading. For a 1000 h durability testing of solid polymer electrolyte showed that both the resistance of and was up to 62337 and 9409 in the presence of 2-NSNa as dopant. Further, the resistances of and were and 874.5 using an ammonium adiapate dopant.
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Lin, Chun-yun, and 林君芸. "Compatibility of LiFePO4 and LiNi1/3Mn1/3Co1/3O2 electrode materials with quaternary-ammonium based ionic liquid mixed with organic solvent electrolyte system." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/82121674113036624634.
Full textAbstract:
碩士國立臺南大學
材料科學系碩士班
100
Ionic liquids (ILs) have been proposed as electrolytes for long-lived and safe LIBs, due to their non-flammability and low volatility. The interactions between cathodes (as olivine LiFePO4 or layered LiNi1/3Mn1/3Co1/3O2 (NMC)) and ionic liquid mixed with organic solvent electrolye were investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scanning electron microscope(SEM), fourier transform infrared (FTIR), and coin cell test. The electrolyte was mixed with an ionic liquid bis(trifluoromethanesulfonyl)imide (TFSI) as anion and tetraethylammonium (N2222) as cation, and ethylene carbonate (EC) and dimethyl carbonate (DMC). The results show that the LiFePO4 cathode in ionic liquid mixed with organic electrolyte has the better rate capability and cycling performance than the NMC cathode. However, the cycling performance of the NMC cathode in the IL based electrolyte is worse than that of the LiFePO4, due to the surface reaction between the IL based electrolyte and the NMC cathode.