<p>The microstructure of the ZEBRA cells was examined at different cycle lifetimes. Various methods of sample preparation were used to remove the NaAlCl₄ electrolyte and expose the cathode microstructure. Features such as layered NiCl₂ crystals, large NaCl grains and needle-like FeCl₂ phases were observed by SEM. The results indicate that nickel particles grow in size with age of the cell. Moreover, the presence of both Na₆FeCl₈ and NiAl₂Cl₈ phases was confirmed by XRD. Thermodynamic modeling was used to predict the phases expected when a cell has undergone overcharge or overdischarge during cycling. It is postulated that some phases observed in the cathode at room temperature may be artifacts due to transformations that occur during cooling and do not exist at the operating temperature.</p> <p>The presence of isolated nickel particles within the cathode was confirmed by SEM and FIB techniques. Furthermore, the conductivity of the NaAlCl₄ electrolyte was measured at high temperatures and various additives were used to make the electrolyte a mixed ionic-electronic conductor.</p> <p>A special cell was designed to measure the conductivity of hygroscopic and volatile electrolyte at high temperatures. The best conductivity was obtained when using 0.2 mole fraction Bi as an additive to the NbCl₅+NaAlCl₄ mixture (Nb:Na=0.3, Bi:Nb=0.2). The conductivity values were doubled between 190 and 500˚C. The DC measurements confirm the presence of electronic conductivity in Bi+NbCl₅+NaAlCl₄ mixtures. In addition, the effect of NaF and Na₂S on the conductivity of the NaAlCl₄ electrolyte was measured.</p> / Doctor of Philosophy (PhD)

The CANDU Supercritical Water-Cooled Reactor’s extreme operating conditions and single-loop design have fuelled a need for better understanding of hydrothermal chemistry. This thesis reports the thermal stability and decomposition kinetics of perchloric acid in quartz and Pyrex® cells. HClO4 is an appropriate internal standard for Raman measurements of nickel(II) chloro complexes in quartz cells up to 200 ºC Raman spectroscopy. This thesis also reports the first Raman spectra for Ni2+, NiCl+ and NiCl2 from 8 to 120 ºC. Due to very weak bands and overlap of the contributing species, a thermodynamic speciation model, principle component analysis, and quantum mechanical predictions of the nickel(II) chloro Raman spectra were required to assign peaks. The assignment was confirmed by calculating temperature independent scattering coefficients from the spectra. This is the first study to obtain a spectrum for NiCl2 below 100 ºC. / University of Guelph, Atomic Energy of Canada Limited (AECL), Bruce Power, University Network of Excellence in Nuclear Engineering (UNENE), National Sciences and Engineering Research Council of Canada (NSERC), Natural Resources Canada, Ontario Power Generation (OPG), Canada Foundation for Innovation

Made available in DSpace on 2017-07-10T15:14:19Z (GMT). No. of bitstreams: 1 Ana Carolina_ Moreno.pdf: 1431859 bytes, checksum: 0d4aa5c4361adead46314fbf8e1b8619 (MD5) Previous issue date: 2015-02-24 / Electricity is one of the main raw materials used in poultry production and it is central to operate and maintain the poultry farms in operation. An aviary requires electricity to supply the various motors and electrical devices that are part of the lighting systems, exhausting, heating, food, among others. Aiming to provide incentives for poultry producers, specifically in the state of Paraná, in 2007, the Poultry Night Program was implemented, in which the government grants discounts in electricity tariff for poultry farmers at night. In this work it was proposed different energy storage systems by using lead-acid batteries and nickel chloride and sodium batteries for supplying loads of four poultry located in the city of Francisco Alves, PR, over a year. For this, it was studied the feasibility of using energy storage systems with battery bank in the higher tariff period and charging the battery bank in the reduced tariff period, comprising of 9:30 PM to 6:00AM (next day). For this project, the two storage systems proved to be uneconomical, since the initial investments by the battery banks are very high compared with the costs avoided with electricity through the use of these systems. KEYWORDS: energy / A energia elétrica é um dos principais insumos utilizados na produção avícola, sendo fundamental para operar e manter os aviários de frango de corte em funcionamento. Um aviário necessita de energia elétrica para alimentar os diversos motores e dispositivos elétricos que compõem os sistemas de iluminação, exaustão, aquecimento, alimentação, entre outros. Visando dar incentivo aos produtores de frangos de corte, especificamente no estado do Paraná, em 2007, foi implantado o Programa Avicultura Noturna, no qual o governo concede descontos na tarifa de energia elétrica para avicultores no período noturno. Neste trabalho foram propostos diferentes sistemas de armazenamento de energia através da utilização de baterias de chumbo-ácido e baterias de cloreto de níquel e sódio para alimentar o conjunto de cargas de quatro aviários situados no município de Francisco Alves-PR, ao longo de um ano de alojamento de aves. Para isto foi estudada a viabilidade de utilização dos sistemas de armazenamento de energia através de banco de baterias no período de tarifa mais elevada e carregamento do banco de baterias no período de tarifa reduzida, que compreende das 21h 30 min às 6 horas (dia seguinte). Para este projeto, os dois sistemas de armazenamento propostos se mostraram inviáveis economicamente, uma vez que o investimento inicial dos bancos de baterias são muito elevados se comparados com os gastos evitados com energia elétrica através do uso destes sistemas.

La montée en puissance des systèmes de production de l'énergie électrique, à partir de centrales éoliennes ou photovoltaïques, a fait apparaître un besoin aigu en moyens de stockage de cette énergie. Les technologies d'accumulateurs électrochimiques sont à même de répondre à cette problématique, en particulier les batteries sodium chlorure de nickel, une technologie d'accumulateur à haute température. Mais afin de gérer au mieux les performances de ces batteries, il est nécessaire d'avoir une connaissance approfondie du comportement électrothermique des cellules unitaires les composant. Ce travail de thèse présente en détail le développement d'un modèle multiphysique 2D d'une cellule Na-MCl2 commerciale, à même de simuler son fonctionnement en décharge à courant constant. Ce modèle a été construit sur une étude approfondie des mécanismes électrochimiques à l'œuvre dans ce type de technologie, et des effets thermiques associés. Il repose également sur la synthèse et la critique des modèles proposés précédemment dans la littérature. Le modèle inédit proposé dans ce manuscrit permet de prendre en compte deux réactions électrochimiques simultanées, ainsi que le comportement thermique de la cellule. Le modèle a été validé en confrontant les résultats de simulations aux performances électriques réelles d'une cellule commerciale Na-MCl2 (incluant une caractérisation des phénomènes électrochimiques par voltammetrie cyclique). Ce modèle permet de simuler avec succès des décharges à courant constant à différents régimes, et à partir de différentes températures. Il est également capable de prévoir les effets électrothermiques qui seraient consécutifs à un changement de design de la cellule (design structurel et de constitution). / The growing production capacity of wind turbines or photo-voltaic plants has revealed an acute need for electric energy storage systems. Electrochemical accumulator technologies are able to address this issue, in particular sodium nickel chloride batteries, a high temperature battery system. But to enhance the energy management of these batteries, it is necessary to have a deep knowledge of the electro-thermal behavior of its unit cell component. This thesis presents the development of a comprehensive multiphysics 2D model of a commercial Na-MCl2 cell, able to simulate its operation in constant current discharge. This model was built on a thorough study of electrochemical mechanisms at work with this type of technology, and its associated thermal effects. It is also based on the synthesis of existing models, and their critique. The new model proposed in this manuscript can take into account two simultaneous electrochemical reactions, as well as the thermal behavior of the cell. The model was validated by comparison between simulation results and the actual electrical performances of a commercial Na-MCl2 cell (including the characterization of electrochemical phenomena by cyclic voltammetry). This model successfully simulates constant current discharges at different rates, and from different temperatures. It is also capable of predicting the electro-thermal effects consecutive to design changes of the cell (structural and relevant to the active material).