Thesis (Ph. D.)--Brigham Young University Dept. of Chemical Engineering, 2006. / Includes bibliographical references (p. 155-165).

Thesis (Ph. D.)--State University of New York at Binghamton, Materials Science, 2005. / Numerals in chemical formula in title are "subscript" in t.p. of printed version. Includes bibliographical references.

Thesis (Ph.D.)--Wake Forest University. Dept. of Physics, 2006. / Vita. Includes bibliographical references (leaves 90-95)

By replacing the intercalation electrode with a porous electrode and allowing lithium to react directly with O₂ from the air, the new rechargeable Li/O₂ battery system was studied. The porous cathode is comprised of carbon, catalyst and binder. The effect of every component was investigated. The catalyst was believed to play an important role in the performance of the electrode. A number of potential materials have been examined as the catalyst for the O₂ electrode. It suggests that the nature of the catalyst is a key factor controlling the performance of the O₂ electrode. Several catalysts based on first row transition metal oxides each with three different morphologies, bulk, nanoparticulate and mesoporous were studied. The influence of the morphology on the discharge and charge voltage, discharge capacity and cyclability were examined. Among all the catalysts studied, α-MnO₂ nanowires was found to be the best candidate. The reversible capacities of 3000 mAhg⁻¹(normalised by the mass of carbon) or 505 mAhg⁻¹ (based on the total mass of cathode + O₂ ) was obtained. Some of other factors, such as type of carbon, type of binder, type of electrolyte, the construction of cathode and the modification of the catalyst were also investigated, even just in the early stage. Capacity fading during cycling is the main problem in all the cases. A number of experiments were carried out to understand and attempt to avoid the fading problem. After successful synthesis of mesoporous α-Fe₂O₃ with unique properties (by Jiao et al.), the application of these materials in conventional Li battery was studied. Mesoporous α-Fe₂O₃ with ordered walls, mesoporous α-Fe₂O₃ with disordered walls and Fe₂O₃ nanoparticles were examined. It was also applied to examine the different factors that influence the rate of conversion electrodes, i.e., Li⁺ and e⁻ transport to and within the particles, as well as the rate of the two-phase reaction, demonstrating that for this conversion reaction electron transport to and within the particles is paramount.

Thesis (Ph.D. (Engineering mechanics)) --University of Limpopo, 2004 / This thesis explores the important issues associated with the insertion of Mg2+ and Li+ into the solid materials: molybdenum sulphide and titanium disulphide. This process, which is also known as intercalation, is driven by charge transfer and is the basic cell reaction of advanced batteries. We perform a systematic computational investigation of the new Chevrel phase, MgxMo6S8 for 0 ≤ x ≤ 2, a candidate for high energy density cathode in prototype rechargeable magnesium (Mg) battery systems. Mg2+ intercalation property of the Mo6S8 Chevrel phase compound and accompanied structural changes were evaluated. We conduct our study within the framework of both the local-density functional theory and the generalised gradient approximation techniques. Analysis of the calculated energetics for different magnesium positions and composition suggest a triclinic structure of MgxMo6S8 (x = 1 and 2). The results compare favourably with experimental data. Band-structure calculations imply the existence of an energy gap located ~1 eV above the Fermi level, which is a characteristic feature of the electronic structure of the Chevrel compounds. Calculations of electronic charge density suggest a charge transfer from Mg to the Mo6S8 cluster, which has a significant effect on the Mo-Mo bond length. There is relatively no theoretical work, in particular ab initio pseudopotential calculations, reported in literature on structural stability, cations "site energy" calculations, and pressure work. Structures obtained on the basis from experimental studies of other ternary molybdenum sulphides are examined with respect to pressure-induced structural transformation. We report the first bulk and linear moduli of the new Chevrel phase structures. This thesis also studies the reaction between lithium and titanium disulfide, which is the perfect intercalation reaction, with the product having the same structure over the range of reaction 0  x  1 in LixTiS2. Calculated lattice parameters, bulk moduli, linear moduli, elastic constants, density of states, and Mulliken populations are reported. Our calculations confirm that there is a single phase present with an expansion of the crystalline lattice as is typical for a solid solution, about 10% perpendicular to the basal plane layers. A slight expansion of the lattice in the basal plane is also observed due to the electron density increasing on the sulfur ions. Details on the correlation between the electronic structure and the energetic (i.e. the thermodynamics) of intercalation are obtained by establishing the connection between the charge transfer and lithium intercalation into TiS2. The theoretical determination of the densities of states for the pure TiS2 and Li1TiS2 confirms a charge transfer. Lithium charge is donated to the S (3p) and Ti (3d) orbitals. Comparison with experiment shows that the calculated optical properties for energies below 12 eV agrees well with reflectivity spectra. The structural and electronic properties of the intercalation compound LixTiS2, for x = 1/4, 3/4, and 1, are also investigated. This study indicates that the following physical changes in LixTiS2 are induced by intercalation: (1) the crystal expands uniaxially in the c-direction, (2) no staging is observed. We also focus on the intercalation voltage where the variation of the cell potential with the degree of discharge for LiTiS2 is calculated. Our results show that it can be predicted with these well-developed total energy methods. The detailed understanding of the electronic structure of the intercalation compounds provided by this method gives an approach to the interpretation of the voltage composition profiles of electrode materials, and may now clearly be used routinely to determine the contributions of the anode and cathode processes to the cell voltage. Hence becoming an important tool in the selection and design of new systems. Keywords Magnesium rechargeable battery; Chevrel, Lithium batteries; Li and Mg-ion insertion; TiS2; Mo6S8; Charge transfer; reflectivity, intercalation, elastic constants, voltage, EOS, Moduli. / the National Research Foundation, the Royal Society(U.K),the Council for Scientific and Industrial Research,and Eskom

L’utilisation de batteries de forte puissance et possédant une énergie élevée devient un passage incontournable dans les transports de demain. Les batteries au lithium, qui étaient utilisées principalement pour des applications mobiles peu consommatrices d’énergie, comme les téléphones ou les ordinateurs, ont trouvées leur place au sein des chaînes de traction.L’arrivée de ces technologies implique une nouvelle façon de concevoir les véhicules, ainsi que la mobilité de manière générale. Mais dans cette approche, les constructeurs automobiles sont faces à de nombreux problèmes. Tout d’abord l’énergie électrique embarquée n’est pas un de leurs principaux corps de métier. Ensuite, cette technologie, bien que maitrisée à l’heure actuelle est encore sujette à quelques flous techniques. Une des principales contraintes des batteries au lithium est qu’il est difficile de connaitre la quantité d’énergie restante au sein de la cellule. Pour un téléphone portable, l’impact est minime, mais pour un véhicule les enjeux sont totalement différents.C’est pour répondre à cette question que SEGULA TECHNOLOGIE AUTOMOTIVE à mis en place une thèse CIFRE en partenariat avec le laboratoire IRTES. L’originalité de ces travaux repose sur l’élaboration d’un modèle multi-physique, thermique et électrique, pour des cellules de forte puissance et de forte énergie. De plus le modèle à la particularité de pouvoir être exporté vers des cellules lithium-ion et lithium-polymère, les deux technologies correspondant le mieux au besoin actuel. Enfin, la précision du modèle lui permet d’être implémenté dans un estimateur d’état de charge temps réel, utilisable au sein des véhicules. Les travaux menés au cours de cette thèse sont récapitulés dans ce mémoire de la manière suivante.Tout d’abord un chapitre introduit les principales caractéristiques de la technologie lithium. Il s’agit dans un premier temps de montrer pourquoi nous avons eu besoin de cette technologie au sein des véhicules, pour ensuite détailler le fonctionnement de ces cellules. Dans le même chapitre, les différentes méthodes permettant la modélisation numérique de ces cellules sont introduites, ainsi que les méthodes d’estimation de leur état de charge.Dans le second chapitre, la modélisation multi-physique est détaillée. Il s’agit ici de comprendre et de modéliser le comportement d’une cellule, en réalisant un modèle numérique équivalent permettant de reproduire les comportements électriques et thermiques. Une fois un nouveau modèle développé et validé expérimentalement, le protocole permettant de déterminer ces paramètres est détaillé. Enfin nous conclurons sur la généralisation du modèle numérique et du protocole pour les batteries lithium-ion de différentes capacités, ainsi que pour les cellules lithium-polymère.Le troisième et dernier chapitre propose un estimateur d’état de charge basé sur le modèle numérique présenté au deuxième chapitre, utilisant un système adaptatif, le filtre de Kalman. Ce filtre réalise l’estimation d’un paramètre non mesurable (l’état de charge) à l’aide de paramètres mesurables (courant, tension, température), et d’un modèle numérique. Ce chapitre présente ainsi l’adaptation du filtre pour une estimation de l’état de charge, mais également l’implémentation du filtre pour des simulations. Après de nombreuses comparaisons en simulation et des validations expérimentales, le chapitre se termine sur l’implémentation du filtre dans une carte électronique de développement, afin de réaliser une estimation d’état de charge en temps réel, et ainsi améliorer la gestion des cellules. / The use of high power and high energy batteries becomes a fixture in the transport of tomorrow. But this technology is new because until then, lithium batteries were used for mobile applications which consume low energy, such as mobile and computers. The arrival of these technologies in vehicles involves a new way of designing vehicles and mobility in general. But in this approach, car makers have many problems. First of all, onboard electrical power is not one of their main trades, then this technology, though mastered is still subject to some fuzzy techniques. The main constraint of lithium batteries is that it is very difficult to know the amount of energy remaining in the cell. For a mobile phone, the impact is low, but for a vehicle the issues are totally different. That to respond to this question that this paper is structured as follows.First chapter introduces the main lines of lithium technology. Firstly it show why we needed this technology in vehicles, and then detail the function of these cells. In the same chapter, different methods for numerical modeling of cells are introduced, and the methods for estimating the state of charge of the cells.In the second chapter, numerical modeling is detailed. This is to understand and model the behavior of a cell, by performing a numerical model to reproduce the equivalent electrical and thermal behavior. In this thesis an equivalent circuit model is proposed, and the protocol for determining the parameters of this model. Chapter finally closes with the generalization of the numerical model and the protocol for lithium batteries modeling, and for different capacities and Lithium-ion and Lithium-polymer cells.The third and final chapter, offers a state estimator based on the numerical model presented in chapter two, and using a Kalman filter. This chapter provides the adaptive filter to estimate the charge state, but also the filter implementation for simulations. After many comparisons in simulation, the chapter ends with the implementation of the filter in a development board to make an estimation of state of charge in real time, thereby improving the management of cells

Abstract not available

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 178-184). Available also in a digital version from Dissertation Abstracts.

Thesis (Ph. D.)--State University of New York at Binghamton, Materials Science and Engineering Program, 2009. / Includes bibliographical references.

In this work, a hybrid power module comprising of a direct methanol fuel cell (DMFC) and a Li-ion battery has been proposed for low power applications. The challenges associated with low power and small DMFCs were investigated and the performance of commercial Li-ion batteries was evaluated. At low current demand (or low power), methanol leakage through the proton exchange membrane (PEM) reduces the efficiency of a DMFC. Consequently, a proton conducting methanol barrier layer made from phospho-silica glass(PSG) was developed. At optimized deposition conditions, the PSG layers had low methanol permeability and moderate conductivity. The accumulation of CO2 inside the fuel tank was addressed by fabricating CO2 vents. Poly (dimethyl siloxane) (PDMS) and poly (1-trimethyl silyl propyne) (PTMSP) base polymers were used as the backbone material for these vents. The selectivity of CO2 transport through the vent was further enhanced by using additives like 1, 6-divinylperfluorohexane. Finally, the effects of self-discharge and voltage loss were evaluated for Panasonic coin cells and thin film LiPON cells. It was observed that the thin film battery outperformed the others in terms of low energy loss. Nonetheless, the performance of small Panasonic coin cells with vanadium oxide cathode was comparable at low discharge rates of less than 0.01% depth of discharge. Lastly, it was also observed that the batteries have stable cycles at low discharge rates.