Thèses sur le sujet « Ion Conducting Polymer Electrolytes »
Pour voir les autres types de publications sur ce sujet consultez le lien suivant : Ion Conducting Polymer Electrolytes.
Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres
Consultez les 50 meilleures thèses pour votre recherche sur le sujet « Ion Conducting Polymer Electrolytes ».
À côté de chaque source dans la liste de références il y a un bouton « Ajouter à la bibliographie ». Cliquez sur ce bouton, et nous générerons automatiquement la référence bibliographique pour la source choisie selon votre style de citation préféré : APA, MLA, Harvard, Vancouver, Chicago, etc.
Vous pouvez aussi télécharger le texte intégral de la publication scolaire au format pdf et consulter son résumé en ligne lorsque ces informations sont inclues dans les métadonnées.
Parcourez les thèses sur diverses disciplines et organisez correctement votre bibliographie.
1
Willgert, Markus. « Solid Polymer Lithium-Ion Conducting Electrolytes for Structural Batteries ». Doctoral thesis, KTH, Ytbehandlingsteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-144169.
Texte intégralRésumé :
This work comprises the manufacture and characterization of solid polymer lithium ion conducting electrolytes for structural batteries. In the study, polymer films are produced in situ via a rapid versatile UV irradiation polymerization route, in which ethylene oxide methacrylates are polymerized into thermoset networks. In the first part of the study, the simplicity and efficiency of this manufacturing route is emphasized. Polymer electrolytes are pro-duced with an ionic conductivity ranging from 5.8×10-10 S cm-1 up to 1.5×10-6 S cm-1, and a storage modulus of up to 2 GPa at 20°C. In the sec-ond part, the effect of the lithium salt content is studied, both for tightly crosslinked systems with a glass transition temperature (Tg) above room temperature but also for sparsely crosslinked system with a Tg below. It is shown that for these systems, there is a threshold amount of 4% lithium salt by weight, above which the ion conducting ability is not affected to a larger extent when the salt content is increased further. It is also shown that the influence of the salt content on the ionic conductivity is similar within both systems. However, the Tg is more affected by the addition of lithium salt for the loosely crosslinked system, and since the Tg is the main affecting parame-ter of the conductivity, the salt content plays a larger role here. In the third part of the study, a thiol functional compound is added via thiol-ene chemistry to create thio-ether segments in the polymer network. This is done in order to expand the toolbox of possible building blocks usable in the design of structural electrolytes. It is shown that solid polymer electrolytes of more homogeneous networks with a narrower glass transition region can be produced this way, and that they have the ability to function as an electrolyte. Finally, the abilities of reinforcing the electrolytes by nano fibrilar cellulose are investigated, by means to improve the mechanical properties without decreasing the ionic conductivity at any larger extent. These composites show conductivity values close to 10-4 S cm-1 and a storage modulus around 400 MPa at 25 °C.QC 20140410
2
Willgert, Markus. « Solid Polymer Lithium-ion Conducting Electrolytes for Structural Batteries ». Licentiate thesis, KTH, Ytbehandlingsteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-107182.
Texte intégral
3
LINGUA, GABRIELE. « Newly designed single-ion conducting polymer electrolytes enabling advanced Li-metal solid-state batteries ». Doctoral thesis, Politecnico di Torino, 2022. http://hdl.handle.net/11583/2969103.
Texte intégral
4
Best, Adam Samuel 1976. « Lithium-ion conducting electrolytes for use in lithium battery applications ». Monash University, School of Physics and Materials Engineering, 2001. http://arrow.monash.edu.au/hdl/1959.1/9240.
Texte intégral
5
Shen, Kuan-Hsuan. « Modeling ion conduction through salt-doped polymers : Morphology, ion solvation, and ion correlations ». The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1595422569403378.
Texte intégral
6
Guo, Jiao. « Development of Ion Conductive Polymer Gel Electrolytes and Their Electrochemical and Electromechanical Behavior Studies ». University of Akron / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=akron1279140041.
Texte intégral
7
Álvarez, Daniel Jardón. « Study of advanced ion conducting polymers by relaxation, diffusion and spectroscopy NMR methods ». Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/18/18158/tde-19102016-114611/.
Texte intégralRésumé :
Advances on secondary lithium ion batteries imply the use of solid polymer electrolytes, which represent a promising solution to improve safety issues in high energy density batteries. Through dissolution of lithium salts into a polymeric host, such as poly(ethylene oxide) (PEO), ion conducting polymers are obtained. The Li+ ions will be localized in the proximity of the oxygen atoms in the PEO chains and thus, their motion strongly correlated with the segmental reorientation of the polymer. Nuclear magnetic resonance (NMR) spectroscopy, translational diffusion coefficients and transverse relaxation times (T2) contribute to the understanding of the involved structures and the ongoing dynamical processes in ionic conductivity. Nuclei with different motional freedom can present different T2 times. T2xT2 exchange experiments enable studying exchange processes between nuclei from different motional regimes. In this work, three different ion conducting polymers were studied. First, PEG was doped with different amounts of LiClO4. 7Li NMR relaxometry measurements were done to study dynamical behavior of the lithium ions in the amorphous phase. All samples presented two lithium types with clearly differentiated T2 times, indicating the presence of two regions with different dynamics. The mobility and consequently the T2 times, increases with temperature. It was observed, that the doping ratio strongly influences the dynamics of the lithium ions, as the amount of crystalline PEG is reduced while increasing the polarity of the sample. A local maximum of the mobility was observed for y = 8. With the T2xT2 exchange experiments exchange rates between both lithium sites were quantified. Second, the triblock copolymer PS-PEO-PS doped with LiTFSI was studied with high resolution solid state NMR techniques as well as with 7Li relaxometry measurements. T1ρ and spin diffusion measurements gave insight on the influence of the doping and the PS/PEO ratio on the mobility of the different segments and on interdomain distances of the lamellar phases. Third, multiple quantum diffusion measurements were applied on poly(ethylene glycol) distearate (PEGD) doped with LiClO4. Therefore, triple quantum states of the 3/2 nucleus 7Li were excited. After optimizing the experimental procedure, it was possible to obtain reliable diffusion coefficients using triple quantum states.O avanço da tecnologia em baterias secundárias de íons lítio envolve o uso de polímeros condutores iônicos como eletrólitos, os quais representam uma solução promissora para obter baterias de maior densidade de energia e segurança. Polímeros condutores são formados através da dissolução de sais de lítio em uma matriz polimérica, como o poli(óxido de etileno) (PEO). Os íons de lítio estão localizados próximos aos oxigênios do PEO, de tal forma que seu movimento está correlacionado com a reorientação das cadeias poliméricas. Espectroscopia por Ressonância magnética nuclear (RMN), junto com medidas de difusão translacional e tempos de relaxação transversal (T2) contribuem para elucidar as estruturas e os processos dinâmicos envolvidos na condutividade iônica. Núcleos com diferente liberdade de movimentação podem ter tempos de T2 diferentes. Experimentos de T2xT2 permitem correlacionar sítios de diferentes propriedades dinâmicas. Neste trabalho, três diferentes polímeros condutores iônicos foram estudados. Primeiro, PEG foi dopado com LiClO4. As propriedades dinâmicas dos íons lítio na fase amorfa foram estudadas com medidas de relaxometria por RMN do núcleo 7Li. Todas as razões de dopagem apresentaram dois T2 diferentes, indicando dos tipos de lítio com dinâmica diferente. A mobilidade, e consequentemente os tempos T2 aumentam com aumento da temperatura. Foi identificado que a dopagem fortemente influencia a dinâmica dos íons lítio, devido à redução da fase cristalina PEG e o aumento da polaridade na amostra. Um máximo local da mobilidade foi observado para y = 8. Com o experimento T2xT2 foram quantificadas as rações de troca entre os dois tipos de lítio. Segundo, o copolímero tribloco PS-PEO-PS dopado com LiTFSI foi analisado através de técnicas de RMN de estado sólido de alta resolução assim como através de medidas de relaxação de 7Li. Medidas de T1ρ e difusão de spin mostraram a influência da dopagem e da razão PS/PEO na mobilidade dos diferentes segmentos e nas distâncias interdomínio das fases lamelares. Terceiro, medidas de difusão através de estados de múltiplos quanta foram feitas em diesterato de polietileno glicol (PEGD) dopado com LiClO4. Estados de triplo quantum foram criados no núcleo 7Li, spin 3/2. Após garantir a eficiência das ferramentas desenvolvidas, foi possível obter coeficientes de difusão confiáveis.
8
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.
Texte intégral
9
Spence, Graham Harvey. « New polymer and gel electrolytes for potential application in smart windows ». Thesis, Heriot-Watt University, 1998. http://hdl.handle.net/10399/614.
Texte intégral
10
Vijayakumar, V. « Preparation, characterization and application of proton, lithium and zinc-ion conducting polymer electrolytes for supercapacitors, lithium- and zinc-metal batteries ». Thesis(Ph.D.), CSIR-National Chemical Laboratory, 2021. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/5972.
Texte intégralRésumé :
The use of liquid electrolytes in energy storage devices are associated with several constraints pertaining to safety. Polymer electrolytes are suitable candidates to overcome several problems associated with free-flowing liquid electrolytes. The current thesis deals with the development of proton, lithium, and zinc conducting gel polymer electrolytes for electrochemical energy storage devices such as supercapacitors, lithium-metal batteries, and zinc-metal batteries. Special emphasis is given to the improvement of electrode|electrolyte interface in polymer electrolyte-based energy storage devices by the ultraviolet-light-induced in situ processing strategy. Ultimately, the prospects of employing polymer electrolytes as an alternative to liquid electrolytes in energy storage devices is revisited in this dissertation through four dedicated working chapters.University Grants Commissions (UGC), India CSIR, India
AcSIR
11
Ghosh, Braja Dulal. « Effect of polymer structure on ion transport in an anhydrous proton conducting electrolyte / ». Full text available from ProQuest UM Digital Dissertations, 2008. http://0-proquest.umi.com.umiss.lib.olemiss.edu/pqdweb?index=0&did=1850432511&SrchMode=1&sid=1&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1279568827&clientId=22256.
Texte intégralRésumé :
Thesis (Ph.D.)--University of Mississippi, 2008.Typescript. Vita. "April 2008." Dissertation director: Jason E. Ritchie Includes bibliographical references (leaves 114-115). Also available online via ProQuest to authorized users.
12
Kidd, Bryce Edwin. « Multiscale Transport and Dynamics in Ion-Dense Organic Electrolytes and Copolymer Micelles ». Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/82525.
Texte intégralRésumé :
Understanding molecular and ion dynamics in soft materials used for fuel cell, battery, and drug delivery vehicle applications on multiple time and length scales provides critical information for the development of next generation materials. In this dissertation, new insights into transport and kinetic processes such as diffusion coefficients, translational activation energies (Ea), and rate constants for molecular exchange, as well as how these processes depend on material chemistry and morphology are shown. This dissertation also aims to serve as a guide for material scientists wanting to expand their research capabilities via nuclear magnetic resonance (NMR) techniques. By employing variable temperature pulsed-field-gradient (PFG) NMR diffusometry, which can probe molecular transport over nm – μm length scales, I first explore transport and morphology on a series of ion-conducting materials: an organic ionic plastic crystal, a proton-exchange membrane, and a polymer-gel electrolyte. These studies show the dependencies of small molecule and ion transport on modulations to material parameters, including thermal or magnetic treatment, water content, and/or crosslink density. I discuss the fundamental significance of the length scale over which translational Ea reports on these systems (~ 1 nm) and the resulting implications for using the Arrhenius equation parameters to understand and rationally design new ion-conductors. Next, I describe how NMR spectroscopy can be utilized to investigate the effect of loading a small molecule into the core of a spherical block copolymer micelle (to mimic, e.g., drug loading) on the hydrodynamic radius (rH) and polymer chain dynamics. In particular, I present spin-lattice relaxation (T1) results that directly measure single chain exchange rate kexch between micelles and diffusion results that inform on the unimer exchange mechanism. These convenient NMR methods thus offer an economical alternative (or complement) to time-resolved small angle neutron scattering (TR-SANS).Ph. D.
13
Weldekidan, Ephrem Terefe. « Design of lithium ion conducting porous hybrid materials for the development of solid Li-battery electrolytes ». Thesis, Aix-Marseille, 2019. http://www.theses.fr/2019AIXM0707.
Texte intégralRésumé :
Dans ce travail, des matériaux hybrides polymères-silice poreuse sous forme de poudre et de film mince ont été synthétisés et caractérisés. L'étude préliminaire de leurs conductivité ionique Li+ a également été réalisée. Les poudres hybrides ont été synthétisées par voie sol-gel en utilisant des triblocs classiques (Pluronic, P123) et des diblocs copolymères amphiphiles bifonctinels fabriqués en laboratoire comme agents dirigeant la structure (SDA). Dans le premier cas, la modification post-synthétique a été utilisée pour fonctionnaliser la surface des pores de la silice avec du PEO. Dans un second temps, la fonctionnalisation de la surface des pores avec le bloc hydrophile (PEO) a été réalisée par extraction du bloc hydrophobe. Des films de silice avec des mésocanaux ordonnés de manière hexagonale et orientés verticalement ont été synthétisés sur la surface de l'électrode via un procédé d'auto-assemblage électro-assisté dans des conditions hydrodynamiques. Les films formés sont mésoporeux (3 nm de diamètre) et entièrement accessibles. Un film de 660 nm d'épaisseur a été obtenu en 200 secondes. Ce film a été fonctionnalisé avec du PEO puis du sel de lithium par le biais d'une méthode d'imprégnation en solution. La conductivité ionique des matériaux hybrides a été étudiée après la mise en forme de la poudre sous forme de pastille ou de film directement formé à la surface de l'électrode. Les résultats montrent la conductivité des ions Li+ apportée aux matériaux. Les pastilles ont une porosité interparticulaire de 40% et le remplissage avec l’électrolyte polymère a un effet positif sur l’optimisation de la conductivité des pastillesIn this work, porous polymer-silica hybrid materials as a powder and thin film are synthesized and characterized. The preliminary study of their Li+ ionic conductivity properties are carried out as well. Here, the polymer electrolyte is embedded in silica matrix - polymer-in-ceramic approach. The hybrid powders are synthesized through sol-gel using conventional triblock (Pluronic, P123) and laboratory made bifunctional diblock amphiphilic copolymers as structure directing agents (SDA). In the first case, post-synthetic modification is used to functionalize the pore surface of silica with PEO. The second allowed to direct functionalization the pore surface with hydrophilic block (PEO) through extraction of hydrophobic block. Particle-free mesoporous silica films with hexagonally ordered and vertically oriented mesochannels are synthesized on electrode surface via electro-assisted self-assembly method under hydrodynamic condition. The resulting films are mesoporous (a diameter of 3 nm) and fully accessible. A film with thickness of 660 nm was grown in 200 s, and functionalized with PEO and then lithium salt through solution impregnation method. The ionic conductivity properties of hybrids were performed after shaping the powder as a pellet or with the hybrid film directly formed on the electrode surface. The results showed that the Li+ conductivity brought to the materials. The pellets have 40 % interparticle porosity and filling this with polymer electrolyte has positive effect on optimizing conductivity of the pellets (2.0 x 10-7 Scm-1 for 35 % filling and 6.8 x 10-7 Scm-1 for 100% filling at 25 °C)
14
Itakura, Tomoya. « Synthesis and Characterization of Proton Conducting Coordination Polymers Working under Low-humidity Condition ». Kyoto University, 2017. http://hdl.handle.net/2433/217993.
Texte intégral
15
Schlindwein, Walkiria Santos. « Conducting polymers and polymer electrolytes ». Thesis, University of Leicester, 1990. http://hdl.handle.net/2381/33889.
Texte intégralRésumé :
Polymers are mostly used as insulator materials. Since the late sixties, two new classes of polymeric materials possessing either ionic or electronic conductivities have been extensively studied. The work carried out in this thesis concerns of the study of polymer electrolytes based on poly(ethylene oxide) (PEO) complexed with divalent salts (ionic conductors) and polypyrroles (PPy) electrochemically and chemically prepared (electronic conductors). Different techniques were used to study their properties including Differential Scanning Calorimetry (DSC), Variable Temperature Polarising Microscopy (VTPM), Extended X-ray Absorption Fine Structure (EXAFS), a.c. Impedance, Cyclic Voltammetry, and Fourier Transform Infra-Red Spectroscopy (FTIR). Water-cast films of PEOn:ZnX2 (X = C1, Br, I) were prepared at a range of stoichiometries. The effects of either residual presence of water or thermal treatment related to the formation of high melting crystalline materials were investigated. The morphology of the zinc halides films differs from similar films cast from acetonitrile/methanol mixtures. The presence of high melting crystalline material in the water cast samples is influenced mostly by the concentration, type of anion and drying procedure applied to the samples. The high melting crystalline materials in the zinc samples are more affected by the drying regime. In some cases, solvent effects can be removed by using a high temperature (e.g. 180°C) drying regime. The presence of water normally depresses the melting temperature of the crystalline structures. Films of PEOn.:CaBr2 and PEOn:NiBr2 cast from water were also examined. The high melting crystalline materials in the calcium samples are more affected by the presence of water. The nickel samples are highly crystalline and the presence of high melting material does not seem to be influenced by either the presence of solvent or the drying procedure. EXAFS was used as a suitable technique to probe the local structure surrounding the cation. The results of the zinc halide samples gave some indication of the interionic and polymer-cation interactions. It was demonstrated that the halogen provides the most substantial contribution for the total EXAFS spectrum and the oxygen contribution is much less significant, except in the case of PEOn:ZnC12 samples. This could be due to the size of the nearest neighbour atoms and/or to the interaction polymer-cation. The presence of neutral "ion pairing" is suggested for the PEOn:ZnBr2 samples. The EXAFS results for the samples containing NiBr2 indicated a strong interaction between polymer-salt and the local structure was dependent on concentration, unlike the zinc samples. The polymerisation of pyrrole was investigated by using chemical and electrochemical oxidation routes. The structural characterisation of the compounds obtained was limited by their insolubility. The electrochemically prepared samples presented higher conductivity than the ones which were chemically prepared. The EXAFS results at the Fe K-edge of the PPyFeCl4 sample, which was prepared by direct chemical oxidation, suggested that the iron is coordinated to oxygens at a distance 1.97 A, chlorines at 3.08 A and perhaps nitrogens at 3.72 A. The iron local structure of the composite PVA/PPy doped with FeCl3 was different from the PPyFeCl4 sample. The iron in the composite sample was coordinated to oxygens at 1.98 A and chlorines at 2.18 A. Alternatively, the presence of a distorted FeCl4- is considered.
16
Rendon, Piedrahita Camilo. « Study of highly conductive, flexible polymer electrolyte membranes and their novel flexoelectric effect ». University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1541440496157425.
Texte intégral
17
Fu, Guopeng. « INVESTIGATION ON THE STRUCTURE-PROPERTY RELATIONSHIPS IN HIGHLY ION-CONDUCTIVE POLYMER ELECTROLYTE MEMBRANES FOR ALL-SOLID-STATE LITHIUM ION BATTERIES ». University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1508508844968127.
Texte intégral
18
Shi, Jie. « Ion transport in polymer electrolytes ». Thesis, University of St Andrews, 1993. http://hdl.handle.net/10023/15522.
Texte intégralRésumé :
The ion-polymer and ion-ion interactions in polymer electrolytes based on high molecular weight, amorphous methoxy-linked PEO (PMEO) and lithium salts have been investigated by conductivity measurement, magic-angle spinning NMR (mas NMR) and pulsed field gradient NMR (pfgNMR) techniques. In the very dilute salt concentration region, ion pairing effects are dominant in these polymer electrolytes. Ion association is found to increase with temperature and salt concentration. Ion transport for these electrolytes is controlled both by segmental motion of the polymer and activation process, in which the former is important for the dilute concentration samples while the latter is important for the concentrated samples. The mass transport process in polymer electrolytes based on a zinc salt has been investigated by steady state dc polarisation and Hittorf techniques. Zinc ion constituents in these electrolytes are mobile with a limiting current fraction of about 0.2 at 80°C, and the transference number measured by the Hittorf method is less than 0.1. The main species in these electrolytes are proposed to be neutral mobile triples. The electrode-electrolyte interfaces in polymer electrolytes based on calcium and magnesium salts have been studied. Dc polarisation experiments for these polymer electrolytes were carried out using two electrode cells with the metal anode and mercury film amalgam cathode. The results of dc polarisation experiments suggest that calcium species are mobile in high molecular weight electrolytes, while magnesium species are immobile. The influence of the molecular weight of the polymer on the dynamics of cation constituents has been studied based on the experimental results of dc polarisation and pfg NMR, and on the theoretical analyses of the reptation theory and the Rouse model. It is found that the transport of the gravity centre of the polymer will influence the ion transport in polymer electrolytes based on PEO in a manner described by the Rouse model when the molecular weight of PEO is less than 3200.
19
Sorrie, Graham A. « Liquid polymer electrolytes ». Thesis, University of Aberdeen, 1987. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU499826.
Texte intégralRésumé :
This thesis is concerned with ion-ion and ion-polymer interactions over a wide concentration range in polymer electrolytes with a view to shedding new light on the mechanism of ion migration. Additionally, the electrochemical stability window of these electrolytes on platinum and vitreous carbon electrodes has been thoroughly investigated. The final part of this thesis is concerned with determining the feasibility of polymer electrolytes as electrolytes in a new type of energy storage device, a double layer capacitor which incorporates activated carbon cloth electrodes. Conductivities and viscosities of solutions of Li, Na and K thiocyanates in low-molecular-weight, non-crystallizable liquid copolymers of ethylene oxide (EO) and propylene oxide (PO) have been measured. The curves of molar conductance versus sqrt c show well-defined maxima and minima. The conductivity is independent of copolymer molecular-weight but is enhanced by raising the EO content of the copolymer. The results are interpreted in terms of a model for ion migration in which ion association and redissociation effects play an important role. It is proposed that the characteristic properties of liquid polymer electrolytes can only be satisfactorily explained if the current is largely anionic. The electrochemical stability window of these electrolytes on platinum is dominated by the presence of a water reduction peak starting at approximately -1.0V which limits the overall stability to approximately 2V. The onset of water reduction is displaced to more negative potentials (-3.0V), thus increasing the stability window, on vitreous carbon electrodes. The value of the double layer capacitance on vitreous carbon electrodes (15-30muF cm-2) agrees well with published data. The double layer capacitance of activated carbon cloth electrodes is lower than anticipated. The importance of faradaic charging and discharging currents to the successful operation of double layer capacitors is indicated but no problems relating to the specific use of polymer electrolytes in such devices were found.
20
Abu-Lebdeh, Yaser. « Proton conducting polymer electrolytes for CO sensors ». Thesis, University of Southampton, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342627.
Texte intégral
21
Meabe, Iturbe Leire. « Innovative polycarbonates for lithium conducting polymer electrolytes ». Thesis, Pau, 2019. http://www.theses.fr/2019PAUU3042.
Texte intégralRésumé :
E 21ème siècle doit faire face à de nouveaux défis sociétaux et environnementaux. Pour cela, la gestion de l’énergie est un élément clé et en particulier le développement des énergies renouvelables. Progressivement les énergies basées sur le solaire, l’éolienne, l’hydraulique, la géothermie et les bio-ressources prennent le pas sur les énergies fossiles. Néanmoins, ces sources d’énergie sont bien souvent intermittentes, par conséquent, il est indispensable de développer des systèmes de stockage d'énergie fiables. Parmi toutes les options le stockage électrochimique semble être le plus prometteur pour les appareils électroniques, les véhicules électriques ainsi que les réseaux. Aujourd’hui, même si les batteries lithium-ion sont largement répandues, car relativement performantes, il reste indispensable de concevoir et de développer de nouvelles batteries répondant mieux encore aux nouvelles contraintes.Une batterie classique est constituée de deux électrodes et entre les deux se trouve l’électrolyte. Actuellement, et en général, dans les batteries commercialisées l’électrolyte est un liquide constitué d’un sel de lithium dissout dans un solvant organique. Celui-ci présente plusieurs risques : i) d’inflammabilité ; ii) de fuite ; iii) de volatilité ; et iv) de toxicité. Ainsi, des recherches sont menées pour développer de nouveaux matériaux polymériques, qui en plus de répondre aux risques mentionnés précédemment, cherchent à optimiser les propriétés de : conductivité ionique, nombre de transport, stabilité électrochimique, stabilité thermique, stabilité mécanique, etc. Parmi les polymères envisagés, les polycarbonates ont montré ces dernières années des propriétés très intéressantes. Dans ce contexte, au cours de la thèse, plusieurs familles de polycarbonates ont été synthétisées par polycondensation, puis évaluées en tant qu'électrolytes polymères solides afin de mettre en évidence l'impact de la structure chimique sur les performancesThe 21st century must address new challenges. The highly qualified life, demanded by modern society, requires constant developments. Energy is the essential ingredient for the economic and social development. The technological revolution that we are now suffering has as a principle the energy produced by coal, oil, and gas. However, the consumption of these energy sources are limited and additionally, during the last decades have been strongly criticized due to the high CO2 emissions released. Besides, the energy produced by renewable energies are promising alternative supplies to limited non-renewable resources. Little by little, the use of fuel-based energy sources will be reduced and renewable solar energy, wind power, hydropower, geothermal energy and bioenergy will be settled in our life. Nevertheless, due to the intermittent availability of these type of resources, good energy storage systems have to be designed. Among the all systems, electrochemical energy storage systems (EESS)s seem to be the best alternative for the use of portable electronics, electric vehicles and smart grid facilities.Generally, a battery contains a liquid electrolyte on it, which is based on a salt dissolved in a liquid organic solvent. This solvent is known to be toxic and highly flammable. Great efforts have been devoted to design safe electrolytes. Thus, polymer electrolytes have been proposed as safe materials. Nevertheless, the ionic conductivity, lithium transference number and electrochemical stability window should be addressed in order to be used in different applications. In this direction, in this thesis different polycarbonates have been proposed as promising host materials and they have been evaluated in as safe electrolytes
22
Kashyap, Aditya Jagannath. « Conducting Polymer Based Gel Electrolytes for pH Sensitivity ». Scholar Commons, 2019. https://scholarcommons.usf.edu/etd/7824.
Texte intégralRésumé :
The evaluation of concentration of ions and molecules with the help of biosensors have been regarded as an emerging technology. Bio and chemical sensors have a variety of applications in the field of medicine, military, environmental and food industries alike. With an estimated investment growth of over 4.31% in the development of pH sensors in the next five year, the objective of a developing a robust measurement system is all the more required. The scope of this research is to evaluate the ability of conducting polymer-based gel electrolytes for pH sensitivity, as a function of the transistor characteristics using an Extended Gate Field Effect Transistor or a conducting film in an electrochemical cell. Polymer gels were prepared by dissolving a suitable conducting polymer in an acidic media. The interaction of the gel with a buffer solution of known pH was collected as electric signals using a glassy carbon as an electrode. The electrochemical cell was further connected to the gate of a Metal-Oxide-Semiconductor Field Effect transistor (MOS-FET). The drain current was measured under two conditions; a) voltage across the gate (VGS) was kept constant, with varying voltage across the drain (VDS) and b) voltage across drain was fixed, while gate voltage changed. The drain current versus voltage of the transistor was plotted as a function of the ion interaction between the gel and the buffer. Different plots were recorded for different values of pH solutions. Final results were plotted to calculate the change in threshold voltage, for every change in pH of the observed solution. pH sensitivity of the gels was further tested through the Electrochemical Impedance Spectroscopy method, using a potentiostat and a three-electrode electrochemical cell. With a small excitation, the AC current flowing through the circuit at different frequencies were recorded and the plots discussed, to evaluate sensitivity to pH.
23
Sahota, Tarsem Singh. « Polymer electrolytes for iontophoretic drug delivery ». Thesis, De Montfort University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.391690.
Texte intégral
24
McHattie, Gillian S. « Ion transport in liquid crystalline polymer electrolytes ». Thesis, University of Aberdeen, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324432.
Texte intégralRésumé :
A systematic study of structure-property relations has been carried out on a range of polymers, both with and without mesogenic moieties. These materials have been characterised using various thermal techniques, including DSC and DMTA. These polymers have been complexed with LiClO4 and the effects of the salt on thermal characteristics have been investigated. In addition, AC impedance spectroscopy has been employed to determine the temperature dependence of the conductivity of these complexes. Results suggest that polymers with mesogenic side groups have the potential to exhibit a conduction mechanism which is independent of both the glass transition temperature of the complex as determined by DSC and the corresponding structural relaxation detected using DMTA. It is found that the glass transition temperature of these materials is determined primarily by the side groups, and not by the polymer backbone. A model is thereby proposed in which ionic motion is decoupled from Tg, but still dependent on the local viscosity of the ionic environment. Appreciable conductivity is therefore observed below the glass transition temperature of the complex, thus resulting in dimensionally stable polymeric complexes with possible applications as solid state electrolytes in batteries.
25
Feng, Chenrun. « Physical and electrochemical investigation of various dinitrile plasticizers in highly conductive polymer electrolyte membranes for lithium ion battery application ». University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1495737492563488.
Texte intégral
26
Lacey, Matthew James. « Electrodeposited polymer electrolytes for 3D Li-ion microbatteries ». Thesis, University of Southampton, 2012. https://eprints.soton.ac.uk/348605/.
Texte intégralRésumé :
The electropolymerisation of vinyl monomers has been investigated as a route to the conformal deposition of thin polymer electrolyte films on porous electrode surfaces, for application in 3D Li-ion microbatteries. The deposition of poly(acrylonitrile) and poly(poly(ethylene glycol) diacrylate) has been monitored using cyclic voltammetry and an electrochemical quartz crystal microbalance (EQCM). It was determined that the polymerisation reaction may be initiated either by direct reduction of the monomer or via a separate reactive intermediate such as the superoxide anion. Furthermore, it was established that film thickness was easily controlled under cyclic voltammetry conditions, for example by varying the number of cycles. However, the choice of solvent and electrode surface was found to be of critical importance. This electropolymerisation technique was adapted to achieve the single step electrodeposition of a gel polymer electrolyte based on poly(ethylene glycol) diacrylate (PEGDA). Modification of the polymer to improve the mechanical properties and ionic conductivity was achieved by the incorporation of silica nanoparticles and plasticising monoacrylates into the polymer matrix. Through these modification procedures a PEGDA-based electrolyte was prepared with an ionic conductivity of the order of 10−4 S cm−1 and demonstrated, for the first time, sufficient mechanical strength to be used as the separator in spring-pressured planar half- and full cell configurations. The conformal nature of the deposit was assessed by scanning electron microscopy (SEM) and it was found that a uniform film of thickness as low as 2 μm was easily achievable. An initial attempt at a full 3D Li-ion microbattery cell based on a carbon foam substrate using composite electrode materials was made. The electrodeposited polymer electrolyte showed good electronic isolation and the cell showed limited cycling ability. The internal structure of the 3D cell was investigated by SEM and x-ray computed tomography.
27
Chen, Songela Wenqian. « Modeling ion mobility in solid-state polymer electrolytes ». Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/122534.
Texte intégralRésumé :
Thesis: S.B., Massachusetts Institute of Technology, Department of Chemistry, 2019Cataloged from PDF version of thesis.
Includes bibliographical references (pages 31-32).
We introduce a course-grained model of ion diffusion in a solid-state polymer electrolyte. Among many tunable parameters, we investigate the effect of ion concentration, ion-polymer attraction, and polymer disorder on cation diffusion. For the conditions tested, we find that ion concentration has little effect on diffusion. Polymer disorder creates local variation in behavior, which we call "trapping" (low diffusion) and "free diffusing" (high diffusion) regions. Changing ion-polymer attraction modulates the relative importance of trapping and free diffusing behavior. Using this model, we can continue to investigate how a number of factors affect cation diffusion both mechanistically and numerically, with the end goal of enabling rapid computational material design.
by Songela Wenqian Chen.
S.B.
S.B. Massachusetts Institute of Technology, Department of Chemistry
28
Maranski, Krzysztof Jerzy. « Polymer electrolytes : synthesis and characterisation ». Thesis, University of St Andrews, 2013. http://hdl.handle.net/10023/3411.
Texte intégralRésumé :
Crystalline polymer/salt complexes can conduct, in contrast to the view held for 30 years. The alpha-phase of the crystalline poly(ethylene oxide)₆:LiPF₆ is composed of tunnels formed from pairs of (CH₂-CH₂-O)ₓ chains, within which the Li⁺ ions reside and along which the latter migrate.¹ When a polydispersed polymer is used, the tunnels are composed of 2 strands, each built from a string of PEO chains of varying length. It has been suggested that the number and the arrangement of the chain ends within the tunnels affects the ionic conductivity.² Using polymers with uniform chain length is important if we are to understand the conduction mechanism since monodispersity results in the chain ends occurring at regular distances along the tunnels and imposes a coincidence of the chain ends between the two strands.² Since each Li⁺ is coordinated by 6 ether oxygens (3 oxygens from each of the two polymeric strands forming a tunnel), monodispersed PEOs with the number of ether oxygen being a multiple of 3 (NO = 3n) can form either “all-ideal” or “all-broken” coordination environments at the end of each tunnel, while for both NO = 3n-1 and NO = 3n+1 complexes, both “ideal” and “broken” coordinations must occur throughout the structure. A synthetic procedure has been developed and a series of 6 consecutive (increment of EO unit) monodispersed molecular weight PEOs have been synthesised. The synthesis involves one end protection of a high purity glycol, functionalisation of the other end, ether coupling reaction (Williamson's type ether synthesis³), deprotection and reiteration of ether coupling. The parameters of the process and purification methods have been strictly controlled to ensure unprecedented level of monodispersity for all synthesised samples. Thus obtained high purity polymers have been used to study the influence of the individual chain length on the structure and conductivity of the crystalline complexes with LiPF₆. The results support the previously suggested model of the chain-ends arrangement in the crystalline complexes prepared with monodispersed PEO² over a range of consecutive chain lengths. The synthesised complexes constitute a series of test samples for establishing detailed mechanism of ionic conductivity. Such series of monodispersed crystalline complexes have been studied and characterised here (PXRD, DSC, AC impedance) for the first time. References: 1. G. S. MacGlashan, Y. G. Andreev, P. G. Bruce, Structure of the polymer electrolyte poly(ethylene oxide)₆:LiAsF₆. Nature, 1999, 398(6730): p. 792-794. 2. E. Staunton, Y. G. Andreev, P. G. Bruce, Factors influencing the conductivity of crystalline polymer electrolytes. Faraday Discussions, 2007, 134: p. 143-156. 3. A. Williamson, Theory of Aetherification. Philosophical Magazine, 1850, 37: p. 350-356.
29
Hekselman, Aleksandra K. « Crystalline polymer and 3D ceramic-polymer electrolytes for Li-ion batteries ». Thesis, University of St Andrews, 2014. http://hdl.handle.net/10023/11950.
Texte intégralRésumé :
The research work presented in this thesis comprises a detailed investigation of conductivity mechanism in crystalline polymer electrolytes and development of a new class of ceramic-polymer composite electrolytes for Li-ion batteries. Firstly, a robust methodology for the synthesis of monodispersed poly(ethylene oxides) has been established and a series of dimethyl-protected homologues with 13, 15, 17, 28, 29, 30 ethylene oxide repeat units was prepared. The approach is based on reiterative cycles of chain extension and deprotection, followed by end-capping of the oligomeric chain ends with methyl groups. The poly(ethylene oxide) homologues show a superior level of monodispersity to previous work and were subsequently used to prepare crystalline PEO6:LiPF6 polymer electrolytes. A correlation between the number of ether oxygens in the polymer chain and the ionic conductivity of crystalline polymer electrolytes has been established. The structure and dynamics of the monodispersed complexes were studied using solid-state NMR spectroscopy for the first time. The results are in agreement with the proposed mechanism of ionic conductivity in crystalline polymer electrolytes. A new class of composite solid electrolytes for all-solid-state batteries with a lithium metal anode is reported. The composite material consists of a 3D interpenetrating network of a ceramic electrolyte, Li₁.₄Al₀.₄Ge₁.₆(PO₄)₃, and an inert polymer (polypropylene), providing continuous pathways for the ionic transport and excellent mechanical properties. 3D connectivity of this novel composite was confirmed using X-ray microtomography and AC impedance spectroscopy.
30
Ainsworth, David A. « Crystalline polymer and small molecule electrolytes ». Thesis, University of St Andrews, 2010. http://hdl.handle.net/10023/2156.
Texte intégralRésumé :
The research presented in this thesis includes a detailed investigation into factors influencing ionic conductivity in the crystalline polymer electrolyte PEO₆:LiPF₆. It has previously been shown that preparing PEO₆:LiPF₆ with PEO modified with larger –OC₂H₅ end groups increases ionic conductivity by one order of magnitude [¹],primarily due to disruption of the crystal structure caused by the inclusion of the larger end groups. In this study it is shown that by reducing PEO molecular weight in crystalline PEO₆:LiPF₆ ionic conductivity is also increased. This was attributed to an increasing concentration of polymer chain end regions upon lowering molecular weight resulting in the creation of more defects, as well as possible increases in crystallite size resulting in longer continuous pathways for ion transport. Similar results were observed using both polydispersed and monodispersed PEO to prepare complexes. In addition, it is demonstrated here that ionic conductivity in crystalline polymerelectrolytes is not confined to PEO₆:LiXF₆ (X=P, As, Sb)[²][³] type materials. The structures and ionic conductivity data are reported for a series of new crystalline polymer complexes: the alkali metal electrolytes. They are composed of low molecular weight PEO and different alkali metal hexafluoro salts (Na⁺, K⁺ and Rb⁺), and include the best conductor poly(ethylene oxide)₈:NaAsF₆ discovered to date [⁴], with a conductivity 1.5 orders of magnitude higher than poly(ethylene oxide)₆:LiAsF₆. A new class of solid ion conductor is reported: the crystalline small-molecule electrolytes. Such materials consist of lithium salts dissolved in low molecular weight glyme molecules [CH₃O(CH₂CH₂O)[subscript(n)]CH₃, n=1-12], forming crystalline complexes [⁵][⁶]. These materials are soft solids unlike ceramic electrolytes and unlike polymer electrolytes they are highly crystalline, are of low molecular weight and have no polydispersity. By varying the number of repeat units in the glyme molecule, many complexes may be prepared with a wide variety of structures. Here, ionic conductivity and cation transference number (t₊) data for several such complexes is presented [⁷][⁸][⁹].These complexes have appreciable ionic conductivities for crystalline complexes and their t₊ values vary markedly depending on the glyme molecule utilized. The differences in t₊ values can be directly attributed to differences in their crystal structures. [¹] Staunton, E., Andreev, Y.G. & Bruce, P.G. Factors influencing the conductivity of crystalline polymer electrolytes. Faraday Discussions 134, 143-156 (2007). [²] Gadjourova, Z., Andreev, Y.G., Tunstall, D.P. & Bruce, P.G. Ionic conductivity in crystalline polymer electrolytes. Nature 412, 6846 (2001). [³] Stoeva, Z., Martin-Litas, I., Staunton, I., Andreev, Y.G. & Bruce, B.G. Ionic Conductivity in the Crystalline Polymer Electrolytes PEO₆:LiXF₆, X = P, As, Sb. J. Am. Chem. Soc. 125, 4619-4626(2003). [⁴] Zhang, C., Gamble, S., Ainsworth, D., Slawin, A.M.Z., Andreev, Y.G. & Bruce, P.G. Alkali metal crystalline polymer electrolytes. Nature Materials 8, 580-584 (2009). [⁵] Henderson, W.A., Brooks, N.R., Brennessel, W.W. & Young Jr, V.G. Triglyme-Li⁺ Cation Solvate Structures: Models for Amorphous Concentrated Liquid and Polymer Electrolytes (I). Chem. Mater. 15, 4679-4684 (2003). [⁶] Henderson, W.A., Brooks, N.R. & Young Jr, V.G. Tetraglyme-Li⁺ Cation Solvate Structures: Models for Amorphous Concentrated Liquid and Polymer Electrolytes (II). Chem. Mater. 15, 4685-4690 (2003). [⁷] Zhang, C., Andreev, Y.G. & Bruce, P.G. Crystalline small-molecule electrolytes. Angewandte Chemie, International Edition 46, 2848-2850 (2007). [⁸] Zhang, C., Ainsworth, D., Andreev, Y.G. & Bruce, P.G. Ionic Conductivity in the Solid Glyme Complexes [CH₃O(CH₂CH₂O)[subscript(n)]CH₃]:LiAsF₆ (n = 3,4). J. Am. Chem. Soc. 129, 8700- 8701 (2007). [⁹] Zhang, C., Lilley, S.J., Ainsworth, D., Staunton, E., Andreev, Y.G., Slawin, A.M.Z. & Bruce, P.G. Structure and Conductivity of Small-Molecule Electrolytes [CH₃O(CH₂CH₂O)[subscript(n)]CH₃]:LiAsF₆ (n = 8-12). Chem. Mater. 20, 4039-4044 (2008).
31
Bayrak, Pehlivan İlknur. « Functionalization of polymer electrolytes for electrochromic windows ». Doctoral thesis, Uppsala universitet, Fasta tillståndets fysik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-204437.
Texte intégralRésumé :
Saving energy in buildings is of great importance because about 30 to 40 % of the energy in the world is used in buildings. An electrochromic window (ECW), which makes it possible to regulate the inflow of visible light and solar energy into buildings, is a promising technology providing a reduction in energy consumption in buildings along with indoor comfort. A polymer electrolyte is positioned at the center of multi-layer structure of an ECW and plays a significant role in the working of the ECW. In this study, polyethyleneimine: lithium (bis(trifluoromethane)sulfonimide (PEI:LiTFSI)-based polymer electrolytes were characterized by using dielectric/impedance spectroscopy, differential scanning calorimetry, viscosity recording, optical spectroscopy, and electrochromic measurements. In the first part of the study, PEI:LiTFSI electrolytes were characterized at various salt concentrations and temperatures. Temperature dependence of viscosity and ionic conductivity of the electrolytes followed Arrhenius behavior. The viscosity was modeled by the Bingham plastic equation. Molar conductivity, glass transition temperature, viscosity, Walden product, and iso-viscosity conductivity analysis showed effects of segmental flexibility, ion pairs, and mobility on the conductivity. A connection between ionic conductivity and ion-pair relaxation was seen by means of (i) the Barton-Nakajima-Namikawa relation, (ii) activation energies of the bulk relaxation, and ionic conduction and (iii) comparing two equivalent circuit models, containing different types of Havriliak-Negami elements, for the bulk response. In the second part, nanocomposite PEI:LiTFSI electrolytes with SiO2, In2O3, and In2O3:Sn (ITO) were examined. Adding SiO2 to the PEI:LiTFSI enhanced the ionic conductivity by an order of magnitude without any degradation of the optical properties. The effect of segmental flexibility and free ion concentration on the conduction in the presence of SiO2 is discussed. The PEI:LiTFSI:ITO electrolytes had high haze-free luminous transmittance and strong near-infrared absorption without diminished ionic conductivity. Ionic conductivity and optical clarity did not deteriorate for the PEI:LiTFSI:In2O3 and the PEI:LiTFSI:SiO2:ITO electrolytes. Finally, propylene carbonate (PC) and ethylene carbonate (EC) were added to PEI:LiTFSI in order to perform electrochromic measurements. ITO and SiO2 were added to the PEI:LiTFSI:PC:EC and to a proprietary electrolyte. The nanocomposite electrolytes were tested for ECWs with the configuration of the ECWs being plastic/ITO/WO3/polymer electrolyte/NiO (or IrO2)/ITO/plastic. It was seen that adding nanoparticles to polymer electrolytes can improve the coloring/bleaching dynamics of the ECWs. From this study, we show that nanocomposite polymer electrolytes can add new functionalities as well as enhancement in ECW applications.
32
Zhang, Hao. « Chemoelectromechanical Actuation in Conducting Polymer Hybrid with Bilayer Lipid Membrane ». VCU Scholars Compass, 2013. http://scholarscompass.vcu.edu/etd/3074.
Texte intégralRésumé :
Biological and bio-inspired systems using ion transport across a membrane for energy conversion has inspired recent developments in smart materials. The active mechanism in bioderived materials is ion transport across an impermeable membrane that converts electrochemical gradients into electrical and mechanical work. In addition to bioderived materials, ion transport phenomenon in electroactive polymers such as ionomeric and conducting polymers produces electromechanical coupling in these materials. Inspired by the similarity in transduction mechanism, this thesis focuses on integrating the ion transport processes in a bioderived material and a conducting polymer for developing novel actuation systems. The integrated membrane has a bilayer lipid membrane (BLM) formed on a conducting polymer, and the proteins reconstituted in the BLM regulate ion transport into the conducting polymer. The properties of the polymer layer in the integrated device are regulated through a control signal applied to the bioderived layer and hence the hybrid membrane resembles an ionic transistor. Due to the bioderived nature of this device, it is referred to as a ‘bioderived ionic transistor’. The research carried out in this thesis will demonstrate the fabrication, characterization and design limitations for fabricating a chemoelectromechanical actuator using the BIT membrane. The BIT membrane has been fabricated using BLM (DPhPC) reconstituted with protein (alamethicin) to gate Na$^+$ transport into conducting polymer membrane (PPy(DBS)). In this membrane, the bioderived layer is fabricated with proteins by vesicle fusion method and conducting polymer is fabricated by electropolymerization. The bioderived layers, the conducting polymer layers and the hybrid membrane are characterized using electrochemical measurements such as cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy. The fabrication, characterization and design effort presented in this thesis focuses on the integration of ion transport through the bioderived membrane into volumetric expansion and bending actuation. The characterization efforts are supported by empirical and physics-based models to represent the input-output relationship for both PPy(DBS) actuator and bioderived membrane, and design rules for the proposed actuation platforms are specified. The electropolymerized PPy(DBS) actuator is anticipated to be used in a bicameral device with the chambers kept separated by the DPhPC-alamethicin bioderived membrane. The relationship between the gradient potential, ionic current through the gate, ion concentration, ion transport coefficient in the conducting polymer layer, and the induced tip displacement in the polymer has been concluded from experiments and fitted to the actuation system model. This thesis will also address future directions for this research and anticipated applications for this hybrid actuation concept, such as artificial muscle, drug delivery.
33
Tang, Shijie. « Development of Multiphase Oxygen-ion Conducting Electrolytes for Low Temperature Solid Oxide Fuel Cells ». Scholarly Repository, 2007. http://scholarlyrepository.miami.edu/oa_theses/112.
Texte intégralRésumé :
One of the major trends of development of solid oxide fuel cells is to reduce the operating temperature from the high temperature range (>950°C) and intermediate temperature range (750-850°C) to the low temperature range (450-650°C). Development of low temperature oxygen ion conducting electrolytes is focused on single-phase materials including Bi2O3 and CeO2-based oxides. These materials have high ion conductivity at the low temperature range, but they are unstable in reducing environments and they are also electronic conductors. In the present research, three types of multiphase materials, Ce0.887Y0.113O1.9435 (CYO)-ZrO2, CYO- yttria-stabilized zirconia (YSZ), and CuO-CYO were investigated. We found that the conductivity of multiphase electrolyte CuO-CYO with a mass ratio of 1:3 is at least 4 times greater than that of CYO and 10 times greater than that of YSZ, the most commonly used material, obtained in the present experiments at 600°C. The enhancement of conductivity in multiphase materials correlates with the level of mismatch between the two phases. Large mismatches in terms of valance and structure result in high vacancy density and hence high oxygen ion conductivity at grain boundaries. This study demonstrates that synthesis of multiphase ceramic materials is a feasible new avenue for development of oxygen ion electrolyte material for low temperature SOFCs.
34
Chintapalli, Mahati. « Ion Transport and Structure in Polymer Electrolytes with Applications in Lithium Batteries ». Thesis, University of California, Berkeley, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10250632.
Texte intégralRésumé :
When mixed with lithium salts, polymers that contain more than one chemical group, such as block copolymers and endgroup-functionalized polymers, are promising electrolyte materials for next-generation lithium batteries. One chemical group can provide good ion solvation and transport properties, while the other chemical group can provide secondary properties that improve the performance characteristics of the battery. Secondary properties of interest include non-flammability for safer lithium ion batteries and high mechanical modulus for dendrite resistance in high energy density lithium metal batteries. Block copolymers and other materials with multiple chemical groups tend to exhibit nanoscale heterogeneity and can undergo microphase separation, which impacts the ion transport properties. In block copolymers that microphase separate, ordered self-assembled structures occur on longer length scales. Understanding the interplay between structure at different length scales, salt concentration, and ion transport is important for improving the performance of multifunctional polymer electrolytes.
In this dissertation, two electrolyte materials are characterized: mixtures of endgroup-functionalized, short chain perfluoropolyethers (PFPEs) and lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) salt, and mixtures of polystyrene-block-poly(ethylene oxide) (PS- b-PEO; SEO) and LiTFSI. The PFPE/LiTFSI electrolytes are liquids in which the PFPE backbone provides non-flammability, and the endgroups resemble small molecules that solvate ions. In these electrolytes, the ion transport properties and nanoscale heterogeneity (length scale ~1 nm) are characterized as a function of endgroup using electrochemical techniques, nuclear magnetic resonance spectroscopy, and wide angle X-ray scattering. Endgroups, especially those containing PEO segments, have a large impact on ionic conductivity, in part because the salt distribution is not homogenous; we find that salt partitions preferentially into the endgroup-rich regions. On the other hand, the SEO/LiTFSI electrolytes are fully microphase-separated, solid, lamellar materials in which the PS block provides mechanical rigidity and the PEO block solvates the ions. In these electrolytes longer length scale structure (∼10 nm – 1 μm) influences ion transport. We study the relationships between the lamellar grain size, salt concentration, and ionic conductivity using ac impedance spectroscopy, small angle X-ray scattering, electron microscopy, and finite element simulations. In experiments, decreasing grain size is found to correlate with increasing salt concentration and increasing ionic conductivity. Studies on both of these polymer electrolytes illustrate that structure and ion transport are closely linked.
35
Kingdom, Rachel Michele. « Conducting Polymer Matrix Poly(2,2’-Bithiophene) Mercuric Metal Ion Incorporation ». Wright State University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=wright1259889438.
Texte intégral
36
Zhang, Ketian. « Mixed ion and electron conducting polymer composite membranes for artificial photosynthesis ». Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/121607.
Texte intégralRésumé :
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2019Cataloged from PDF version of thesis.
Includes bibliographical references.
Inspired by the fact that OH- has a very high mobility in water, highly conductive OH⁻conducting membranes were developed for alkaline water electrolysis. The membranes were semi-interpenetrating networks of crosslinked poly(vinyl alcohol) (PVA) and a polycation miscible with PVA. It is analogous to aqueous strong base solution. The polycation is a OH- containing polymer; PVA solvates this polycation and facilitates the ion conduction via Grotthuss mechanism. The membrane with proper composition has an exceptionally high OH⁻ conductivity of 151 mS/cm, 6.51 times as high as the commercial membrane Neosepta AHA. At the same time, the hydrogen bonds and covalent crosslinks in the system give this membrane a high tensile strength of 41 MPa in the wet state, 46% higher than the Neosepta AHA membrane. Insight in the ion conduction mechanism was gained by spectroscopic studies and the measurement of OH- conduction activation energy.
This material system is also highly anion perm-selective, a feature critical to sustaining the pH gradient in bipolar membrane based artificial photosynthesis devices. A highly transparent mixed proton and electron conducting membrane was developed. The Nafion and reduced graphene oxide (rGO) were chosen as the proton conducting polymer matrix and the electrically conductive filler respectively. The filler has a high aspect ratio. As predicted by simulations, it will have low percolation threshold if homogeneously dispersed. To achieve this homogeneity, water-aided mixing was employed followed by fast freezing in liquid nitrogen. Though rGO is a light absorber, the extremely low percolation threshold (0.1%) allows us to achieve sufficient electrical conductivity with only a small volume fraction of rGO. Therefore, the membrane was highly transparent in addition to its ability to conduct both electrons and protons.
Detailed modeling of the energy loss from conduction, light absorption, and gas crossover was conducted, showing that this material system is promising for the artificial photosynthesis application.
by Ketian Zhang.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Materials Science and Engineering
37
Gautam, Devendraprakash. « Characterization of the conduction properties of alkali metal ion conducting solid electrolytes using thermoelectric measurements ». [S.l. : s.n.], 2006. http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-28873.
Texte intégral
38
Törmä, Erik. « Synthesis and characterisation of solid low-Tg polymer electrolytes for lithium-ion batteries ». Thesis, Uppsala universitet, Institutionen för kemi - Ångström, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-226754.
Texte intégralRésumé :
Electrolytes of poly(trimethylene carbonate-co-ε-caprolactone), poly(TMC-co-CL), and LiTFSI have been prepared and characterised. The copolymers were analysed with GPC and NMR, which showed that random high molecular weight copolymers of desired compositions had been obtained. The electrolytes with varied salt concentration were examined with TGA, DSC, FTIR and impedance spectroscopy. The highest ionic conductivities were measured for the copolymer of 60:40 ratio of TMC:CL and for the homopolymer poly(ε-caprolactone), PCL, both electrolytes with 28 wt% LiTFSI. The ionic conductivity was measured to of the order of 10−3 S cm−1 for the PCL electrolyte and 10−4 S cm−1 for the 60:40 copolymer at 50 °C.
39
Unal, Asuman. « Ion-exchange and charge transport in films of conducting polymer and composite ». Thesis, University of Leicester, 2017. http://hdl.handle.net/2381/40867.
Texte intégralRésumé :
This thesis was concerned with the improvement of novel modified electrodes based on polyaniline (Pani) and its copolymers with o-aminophenol (o-AP) and o-toluidine (o-OT) and the investigation of their defluoridation properties, and further with the enhancement of the charge transport of Pani and polypyrrole (PPy) via multiwall carbon nanotubes (MWCNTs) in Ethaline. The principle of electrochemical ion-exchange modified electrodes is based on the doping/dedoping process of conducting polymer films. This feature makes it possible to remove undesirable ions, such as fluoride, from aqueous solution. The fabrication of Pani and its copolymers with o-AP/o-OT, carried out under optimal conditions by EQCM, gave an excellent opportunity to test for the removal of fluoride ions at pH 6.60 from water without chemical contamination of the copolymer. Pani, and its copolymers with o-AP/o-OT, poly(aniline-co-o-aminophenol) (Pani-PAP) and poly(aniline-co-o-toluidine) (Pani-POT), can theoretically take up about 91.2 mg g-1 fluoride ions per redox site of polymer film. Experiments indicated that the Pani, Pani-PAP and Pani-POT films removed 51.6 ± 1.0 mg g-1, 65.0 ± 0.6 mg g-1 and 66.8 ± 1.8 mg g-1, respectively, of fluoride ions per redox site of each (co)polymer film. This demonstrates that the copolymerisation of aniline with its derivatives enhanced the defluoridation properties of Pani. Pani and PPy are also promising materials for energy storage devices. The presence of MWCNTs to some extent enhanced both the electrochemical properties and mechanical stability in Ethaline, which maintains high efficiency and high-quality depositions through the use of the EQCM technique. The specific mass capacitances of these composite films were determined to be 1170.1 ± 44.7 F g-1 and 120.5 ± 5.4 F g-1 for Pani/MWCNTs and PPy/MWCNTs, respectively.
40
Mbemba, 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.
Texte intégralRésumé :
Ce travail concerne la production d’hydrogène et d’oxygène de pureté électrolytique par électrolyse de l’eau selon le procédé à électrolyte polymère solide. Dans l’état de l’art, les électrolyseurs industriels utilisent des catalyseurs à base de métaux précieux : le platine est utilisé à la cathode pour promouvoir la réaction de dégagement d’hydrogène moléculaire et l’iridium ou ses oxydes sont utilisés à l’anode pour promouvoir la réaction de dégagement d’oxygène moléculaire. En dépit de nombreux avantages, l’emploi de ces métaux précieux constitue un frein au développement à grande échelle de cette technologie d’électrolyse. Dans ce mémoire de thèse, nous présentons un ensemble de résultats relatifs à la synthèse et à la caractérisation électrochimique d’assemblages membrane – électrodes exempts de métaux précieux. Nous montrons que des polyoxométalates ou des clathrochélates de cobalt peuvent être utilisés à la place du platine pour le dégagement d’hydrogène et que des complexes moléculaires de ruthénium peuvent être utilisés à la place de l’iridium pour le dégagement d’oxygène. Nous présentons également un ensemble de résultats obtenus en utilisant des matériaux polymères à conduction par ions hydroxyles. Les performances de ces nouvelles cellules d’électrolyse sont comparées à celles obtenues avec des catalyseurs conventionnels à base de métaux précieuxThe 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
41
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.
Texte intégralRésumé :
Des nanotubes de dioxyde de titane (TiO2nts) sont étudiés comme électrodes négatives potentielles pour des microbatteries Li-ion 3D. Ces TiO2nts lisses et hautement auto-organisés sont élaborés par anodisation du Ti dans des électrolytes organiques à base de glycérol ou d'éthylène glycol contenant des ions fluor et de l'eau en faible quantité. Les structures présentant un diamètre de 100 nm et une longueur variant de 1,5 à 14 µm sont particulièrement appropriés pour l'application visée. Les TiO2nts ont été tapissés de manière conforme par un électrolyte polymère (PMA-PEG) comportant un sel de lithium (LiTFSI) grâce à la technique d'électropolymérisation. Les études morphologiques menées par SEM et TEM ont montré que les nanotubes sont entièrement recouverts d'un film mince polymère de 10 nm d'épaisseur, ce qui permet de préserver la structure 3D de l'électrode. Les tests électrochimiques portant sur les nanotubes seuls ainsi que sur les TiO2nts tapissés d'électrolyte polymère ont été effectués en demi-cellule et en cellule complète en utilisant un électrolyte polymère à base de MA-PEG contenant du LiTFSI. En demi-cellule, les TiO2nts de 1,5 µm de long delivrent une capacité surfacique de 22 µAh cm-2 relativement stable sur 100 cycles. La performance de la demi-cellule est améliorée de 45% à une cinétique de 1C lorsque les TiO2nts sont tapissés de manière conforme par un electrolyte polymère (PMA-PEG). Cet effet résulte d'un meilleur transport de charges lié à l'augmentation de la surface de contact entre l'électrode et l'électrolyteTitania 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
42
Khawaja, Mohamad. « Synthesis and Fabrication of Graphene/Conducting Polymer/Metal Oxide Nanocomposite Materials for Supercapacitor Applications ». Scholar Commons, 2015. http://scholarcommons.usf.edu/etd/5715.
Texte intégralRésumé :
The rising energy consumption worldwide is leading to significant increases in energy production with fossil fuels being the major energy source. The negative environmental impact of fossil fuel use and its finite nature requires the use of alternative sources of energy. Solar energy is a clean alternative energy source; however, its intermittent nature is a major impediment that needs to be reduced or eliminated by the development of cost effective energy storage. Thermal storage in tanks filled typically with molten salt at elevated temperatures is widely used in concentrating solar power plants to generate electricity during periods of low daytime solar radiation or night time. Similarly, electrical storage in batteries, etc. is used in conjunction with photovoltaic solar power plants.
Electrochemical supercapacitors can be effectively used for electrical storage, either alone or in a hybrid configuration with batteries, for large scale energy storage as well as in electric vehicles and portable electronics. Unlike batteries’, supercapacitor electrodes can be made of materials that are either less toxic or biodegradable and can provide almost instantaneous power due to their unique charge storage mechanism similar to conventional capacitors found in most electronics. Unfortunately, the same storage mechanism prevents supercapacitors from having high energy density. The purpose of this dissertation is to investigate organic and inorganic electrode materials that can increase the specific capacitance and energy density of supercapacitors. Additionally, certain types of supercapacitor electrode materials store the charges at the electrode/electrolyte interface preventing any deformation of the material and thus increasing its cycle life by two to three orders of magnitude.
Transition metal oxides, layered transition metal chalcogenides, and their composites with graphene and conducting polymers have been synthesized, characterized, and their electrochemical performances evaluated for suitability as electrode materials for supercapacitor applications. Morphology and crystalline structure characterization methods used, such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR), were used throughout this work. Electrochemical characterization involved cyclic voltammetry (CV), constant current charge and discharge (CCCD), and electrochemical impedance spectroscopy (EIS) in two and three electrode configuration using aqueous and organic electrolytes.
Ruthenium oxide-graphene (RuO2-G) electrodes were tested in the two-electrode cell configuration and exhibit an areal capacitance of 187.5 mF cm-2 in 2M H2SO4 at a RuO2:G ratio of 10:1. Due to RuO2 high toxicity, scarcity, and high cost, manganese oxide-graphene (MnO-G) was used as an alternative but its low specific capacitance remains a major stumbling block.
The electrodes’ mass loading was studied in detail to understand the effects of thickness on the measured specific capacitance. Layered transition metal chalcogenides are structurally similar to graphene but possess different characteristics. Molybdenum sulfide (MoS2) is a two-dimensional material that has lower conductivity than graphene but larger sheet spacing making it easy for other materials to intercalate and form composites such as molybdenum sulfide-polyaniline (MoS2-PANI). MoS2-PANI electrodes, with different thicknesses, were measure in a three-electrode cell configuration resulting in gravimetric capacitance of 203 F g-1 for the thinnest electrode and areal capacitance of 358 mF cm-2 for the thickest electrode; all measurements performed using 1M H2SO4 aqueous electrolyte.
Attempts were also made to reduce the supercapacitor self-discharge by depositing on the electrode a blocking thin layer of barium strontium titanate (BST). The results were rather inconclusive because of the large thickness of the deposited BST layer. However, they strongly suggest that a very thin BST layer could improve the overall capacitance because of the very large dielectric constant of the BST material. Additional work is required to determine its effects on self-discharge.
43
Gautam, Devendraprakash [Verfasser]. « Characterization of the conduction properties of alkali metal ion conducting solid electrolytes using thermoelectric measurements / vorgelegt von Devendraprakash Gautam ». Stuttgart : Max-Planck-Inst. für Metallforschung, 2006. http://d-nb.info/995371202/34.
Texte intégral
44
Andersson, Jonas. « Synthesis of polycarbonate polymer electrolytes for lithium ion batteries and study of additives to raise the ionic conductivity ». Thesis, Uppsala universitet, Strukturkemi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-259513.
Texte intégralRésumé :
Polymer electrolyte films based on poly(trimethylene carbonate) (PTMC) mixed with LiTFSI salt in different compositions were synthesized and investigated as electrolytes for lithium ion batteries, where the ionic conductivity is the most interesting material property. Electrochemical impedance spectroscopy (EIS) and DSC were used to measure the ionic conductivity and thermal properties, respectively. Additionally, FTIR and Raman spectroscopy were used to examine ion coordination in the material. Additives of nanosized TiO2 and powders of superionically conducting Li1.3Al0.3Ti1.7(PO4)3 were investigated as enhancers of ionic conductivity, but no positive effect could be shown. The most conductive composition was found at a [Li+]:[carbonate] ratio of 1, corresponding to a salt concentration of 74 percent by weight, which showed an ionic conductivity of 2.0 × 10–6 S cm–1 at 25 °C and 2.2 × 10–5 S cm–1 at 60 °C, whereas for even larger salt concentrations, the mechanical durability of the polymeric material was dramatically reduced, preventing use as a solid electrolyte material. Macroscopic salt crystallization was also observed for these concentrations. Ion coordination to carbonyls on the polymer chain was examined for high salt content compositions with FTIR spectroscopy, where it was found to be relatively similar between the samples, possibly indicating saturation. Moveover, with FTIR, the ion-pairing was found to increase with salt concentration. The ionic conductivity was found to be markedly lower after 7 weeks of aging of the materials with highest salt concentrations.
45
Duznovic, Ivana [Verfasser], Wolfgang [Akademischer Betreuer] Ensinger et Viktor [Akademischer Betreuer] Stein. « Ion-conducting Nanopores in Polymer Membranes for (Bio)Molecular Sensory Applications / Ivana Duznovic ; Wolfgang Ensinger, Viktor Stein ». Darmstadt : Universitäts- und Landesbibliothek, 2021. http://d-nb.info/1230062440/34.
Texte intégral
46
Skinner, Anna Penn. « Ion Conducting Polyelectrolytes in Conductive Network Composites and Humidity Sensing Applications for Ionic Polymer-Metal Composite Actuators ». Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/71683.
Texte intégralRésumé :
Ionic polymer-metal composites (IPMCs) are widely studied for their potential as electromechanical sensors and actuators. Bending of the IMPC depends on internal ion motion under an electric potential, and the addition of an ionic liquid and ionic self-assembled multilayer (ISAM) conductive network composite (CNC) strongly enhances bending and improves lifetime.
Ion conducting polyelectrolytes poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS) and Nafion® were incorporated into an ISAM CNC film with poly(allylamine hydrochloride) (PAH) and anionic gold nanoparticles actuators to further improve bending. CNC films were optimized for bending through pH adjustments in PAH and adding NaCl to the PAMPS and Nafion® solutions. PAMPS-containing actuators showed larger and faster bending than those containing Nafion® in the CNC.
The IPMC actuator was also evaluated for its potential as a humidity sensor based on its relative humidity (RH) dependent steady-state current. The detection range is at least 10-80%RH, with 5%RH increment differentiation and likely better resolution. Effects of CNC presence and thickness were studied, in conjunction with ionic liquid at a range of RH values. A thin CNC (pH 4 PAH) produced the greatest current differentiation between RH values. The current's response speed to a large RH decrease was approximately 4 times faster than that of a fast commercial digital hygrometer. Additionally, the presence of a CNC and ionic liquid improved the current response time. These results indicate that an IPMC based humidity sensor using a CNC and ionic liquid is very promising and merits further study.Master of Science
47
Karo, Jaanus. « The Rôle of Side-Chains in Polymer Electrolytes for Batteries and Fuel Cells ». Doctoral thesis, Uppsala universitet, Strukturkemi, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-100738.
Texte intégralRésumé :
The subject of this thesis relates to the design of new polymer electrolytes for battery and fuel cell applications. Classical Molecular Dynamics (MD) modelling studies are reported of the nano-structure and the local structure and dynamics for two types of polymer electrolyte host: poly(ethylene oxide) (PEO) for lithium batteries and perfluorosulfonic acid (PFSA) for polymer-based fuel cells. Both polymers have been modified by side-chain substitution, and the effect of this on charge-carrier transport has been investigated. The PEO system contains a 89-343 EO-unit backbone with 3-15 EO-unit side-chains, separated by 5-50 EO backbone units, for LiPF6 salt concentrations corresponding to Li:EO ratios of 1:10 and 1:30; the PFSA systems correspond to commercial Nafion®, Hyflon® (Dow®) and Aciplex® fuel-cell membranes, where the major differences again lie in the side-chain lengths. The PEO mobility is clearly enhanced by the introduction of side-chains, but is decreased on insertion of Li salts; mobilities differ by a factor of 2-3. At the higher Li concentration, many short side-chains (3-5 EO-units) give the highest ion mobility, while the mobility was greatest for side-chain lengths of 7-9 EO units at the lower concentration. A picture emerges of optimal Li+-ion mobility correlating with an optimal number of Li+ ions in the vicinity of mobile polymer segments, yet not involved in significant cross-linkages within the polymer host. Mobility in the PFSA-systems is promoted by higher water content. The influence of different side-chain lengths on local structure was minor, with Hyflon® displaying a somewhat lower degree of phase separation than Nafion®. Furthermore, the velocities of the water molecules and hydronium ions increase steadily from the polymer backbone/water interface towards the centre of the proton-conducting water channels. Because of its shorter side-chain length, the number of hydronium ions in the water channels is ~50% higher in Hyflon® than in Nafion® beyond the sulphonate end-groups; their hydronium-ion velocities are also ~10% higher. MD simulation has thus been shown to be a valuable tool to achieve better understanding of how to promote charge-carrier transport in polymer electrolyte hosts. Side-chains are shown to play a fundamental rôle in promoting local dynamics and influencing the nano-structure of these materials.
48
Kyeremateng, Nana Amponsah. « Advanced materials based on titania nanotubes for the fabrication of high performance 3D li-ion microbatteries ». Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4772/document.
Texte intégralRésumé :
Le développement des dispositifs microélectroniques a dopé la recherche dans le domaine des microbatteries tout solide rechargeables. Mais actuellement, les performances de ces microbatteries élaborées par des technologies couche mince (2D) sont limitées et le passage à une géométrie 3D adoptant le concept “Li-ion” ou“rocking chair” est incontournable. Cette dernière condition implique de combiner des matériaux de cathode comme LiCoO2, LiMn2O4 or LiFePO4 avec des anodes pouvant réagir de manière réversible avec les ions lithium. Parmi tous les matériaux pouvant servir potentiellement d'anode, les nanotubes de TiO2 révèlent des propriétés intéressantes pour concevoir des microbatteries Li-ion 3D. Facilement réalisable, la nano-architecture auto-organisée a montré des résultats très prometteurs en termes de capacités à des cinétiques relativement modérées. L'utilisation des nanotubes de TiO2 en tant qu'anode conduit à des cellules présentant de faible autodéchargeet élimine le risque de surcharge grâce au haut potentiel de fonctionnement (1.72 V vs. Li+/Li). Dans ce travail de thèse, nous avons étudié la substitution des ions Ti4+ par Sn4+ et Fe2+ dans les nanotubes de TiO2. Bien que la présence d'ions Fe2+ n'ait pas amélioré les performances électrochimiques des nanotubes, nous avons pu mettre en évidence l'effet bénéfique des ions Sn4+. Nous avons aussi pu montré que la fabrication de matériaux composites à base de nanotubes de TiO2 et d'oxyde de métaux de transition électrodéposés se présentant sous forme de particules (NiO et Co3O4 ) augmentait les capacités d'un facteur 4The advent of modern microelectronic devices has necessitated the search for high-performance all-solid-state (rechargeable) microbatteries. So far, only lithium-based systems fulfill the voltage and energy density requirements of microbatteries. Presently, there is a need to move from 2D to 3D configurations, and also a necessity to adopt the “Li-ion” or the “rocking-chair” concept in designing these lithium-based (thin-film) microbatteries. This implies the combination of cathode materials such as LiCoO2, LiMn2O4 or LiFePO4 with the wide range of possible anode materials that can react reversibly with lithium. Among all the potential anode materials, TiO2 nanotubes possess a spectacular characteristic for designing 3D Li-ion microbatteries. Besides the self-organized nano-architecture, TiO2 is non-toxic and inexpensive, and the nanotubes have been demonstrated to exhibit very good capacity retention particularly at moderate kinetic rates. The use of TiO2 as anode provides cells with low self-discharge and eliminates the risk of overcharging due to its higher operating voltage (ca. 1.72 V vs. Li+/Li). Moreover, their overall performance can be improved. Hence, TiO2 nanotubes and their derivatives were synthesized and characterized, and their electrochemical behaviour versus lithium was evaluated in lithium test cells. As a first step towards the fabrication of a 3D microbattery based on TiO2 nanotubes, electrodeposition of polymer electrolytes into the synthesized TiO2 nanotubes was also studied; the inter-phase morphology and the electrochemical behaviour of the resulting material were studied
49
Wang, Ying. « Development and Characterization of Advanced Polymer Electrolyte for Energy Storage and Conversion Devices ». Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/83859.
Texte intégralRésumé :
Among the myraid energy storage technologies, polymer electrolytes have been widely employed in diverse applications such as fuel cell membranes, battery separators, mechanical actuators, reverse-osmosis membranes and solar cells. The polymer electrolytes used for these applications usually require a combination of properties, including anisotropic orientation, tunable modulus, high ionic conductivity, light weight, high thermal stability and low cost. These critical properties have motivated researchers to find next-generation polymer electrolytes, for example ion gels.
This dissertation aims to develop and characterize a new class of ion gel electrolytes based on ionic liquids and a rigid-rod polyelectrolyte. The rigid-rod polyelectrolyte poly (2,2'-disulfonyl-4,4'-benzidine terephthalamide) (PBDT) is a water-miscible system and forms a liquid crystal phase above a critical concentration. The diverse properties and broad applications of this rigid-rod polyelectrolyte may originate from the double helical conformation of PBDT molecular chains.
We primarily develop an ionic liquid-based polymer gel electrolyte that possesses the following exceptional combination of properties: transport anisotropy up to 3.5×, high ionic conductivity (up to 8 mS cm⁻¹), widely tunable modulus (0.03 – 3 GPa) and high thermal stability (up to 300°C). This unique platform that combines ionic liquid and polyelectrolyte is essential to develop more advanced materials for broader applications.
After we obtain the ion gels, we then mainly focus on modifying and then applying them in Li-metal batteries. As a next generation of Li batteries, the Li-metal battery offers higher energy capacity compared to the current Li-ion battery, thus satisfying our requirements in developing longer-lasting batteries for portable devices and even electric vehicles. However, Li dendrite growth on the Li metal anode has limited the pratical application of Li-metal batteries. This unexpected Li dendrite growth can be suppressed by developing polymer separators with high modulus (~ Gpa), while maintaining enough ionic conductivity (~ 1 mS/cm). Here, we describe an advanced solid-state electrolyte based on a sulfonated aramid rigid-rod polymer, an ionic liquid (IL), and a lithium salt, showing promise to make a breakthrough. This unique fabrication platform can be a milestone in discovering next-generation electrolyte materials.Ph. D.
50
Okyay, Ozden. « Polymerization Of 2,4,6 Trichlorophenol By Microwave Initiation ». Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12608053/index.pdf.
Texte intégralRésumé :
Polymerization reaction is carried out by the reaction of 2,4,6 trichlorophenol with
sodium hydroxide, in the presence of small amount of water by microwave initiation.
Synthesis of polymers were successfully performed under microwave enegy. The use
of microwave energy was due to advantages of shorter processing time. The main
focus of attention was the 90 to 600 watt microwave energy. Polymerizations were
performed with different time intervals by keeping the microwave energy and water
content constantor with different energy levels by keeping the time interval and water content constant
or by varying the amount of water by keeping the time and energy level constant.Beside poly(dichlorophenylene oxide), conducting polymer, ion-radical polymer, crosslinked polymer were also be successfully synthesized and characterized. Characterizations of the products were performed by FTIR, 1H-NMR, 13C-NMR, DSC, TGA and elemental analysis. Molecular weight distribution was measured by PL-GPC 220 Polymer Laboratories Instrument. Conductivity measurements were performed by four probe technique.