京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第20551号 / 理博第4309号 / 新制||理||1619(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)教授 北川 宏, 教授 竹腰 清乃理, 教授 吉村 一良 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

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As global energy consumption moves away from fossil fuel sources to alternative energy, the concern for energy storage is paramount. Through lithium ion batteries (LIBs), secondary battery storage has been secured for both large applications of electric vehicles, solar storage, and smaller items like personal cell phones and laptops. However, LIBs use flammable liquid electrolytes and due to engineering defects or dendritic short-circuits have the potential to swell, catch on fire, or even explode because of the volatile organic solvents within the battery. In the pursuit of new commercial lithium ion battery technologies that are safe, nonflammable, and highly conductive, solid-state electrolytes (SSE) are promising candidates for these critical innovations. To achieve SSEs with electrochemically and functionally desirable properties such as ease of manufacturing, good adherence to electrodes, and high ionic conductivities, continued efforts are devoted to improving electrolyte materials. The two main electrolyte types of interest are polymer electrolytes and ceramic electrolytes. Although polymer electrolytes have desirable physical flexibility to form good contact with electrode surfaces, they continually suffer from low ionic conductivities comparatively. Meanwhile ceramic electrolytes have high ionic conductivities (especially high cationic conductivities) but suffer from both poor electrode contact and brittleness. Single-ion conductive materials (like most ceramic conductors) are necessary to increase lifetime performance of batteries. An avenue to access these necessary attributes in LIB-SSEs is explored through novel boron-containing polymers and polymer-ceramic hybrids with the focus to synthesize a material with a high lithium transference number. By exploiting the Lewis basic nature of borane centers to form negatively charged polymer backbones, novel solid-state electrolytes were synthesized with the goal of creating only cation-conductive polymer networks by incorporating the anionic component within the polymer matrix. The synthesis, chemical and electrochemical characterization of these types of polymers and polymer-ceramic hybrids are analyzed by various techniques including x-ray diffraction, thermal gravimetric analysis, nuclear magnetic spectroscopy, gel permeation chromatography, electrochemical impedance spectroscopy and lithium transference number characterization. / Chemistry

京都大学 / 新制・課程博士 / 博士(理学) / 甲第23458号 / 理博第4752号 / 新制||理||1681(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)教授 北川 宏, 教授 吉村 一良, 教授 竹腰 清乃理 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

Ionic and osmotic homeostasis, and the intricately linked mechanisms of acid-base balance are critical for the survival of fish. To date, the role of the gastrointestinal (GI) tract in these processes has received only limited study, and our knowledge has been gained almost exclusively through studies conducted in fasting animals. The impacts of feeding and digestion, ubiquitous processes in the natural environment, are likely to be significant but have been overlooked. The current thesis addressed these shortfalls in our current understanding. Research focused on the rainbow trout (Oncorhynchus mykiss), a euryhaline species capable of withstanding the opposing challenges of life in seawater (diffusive influx of ions and loss of water) and freshwater (diffusive loss of ions and gain of water), and concentrated on its physiological response to ingestion of a meal of commercial, dry trout food, containing concentrated salts and little water. The net absorption and secretion of ions and water was tracked in each section of the GI tract of the rainbow trout over a detailed time course using an experimental diet that contained a simple inert marker, in the presence of external freshwater or seawater. Additionally, changes in overall blood chemistry were investigated to examine changes in osmotic, ionic and acid-base regulation during digestion. Feeding in freshwater resulted in the loss of endogenous water to the GI tract during digestion. Additionally, the meal provided much needed ions to balance those lost by diffusion; indeed all of the ingested ions were assimilated along the GI tract except for sodium which was absorbed in the stomach, but secreted in the intestine such that overall sodium balance was close to zero. Feeding also created a metabolic base load (an increase in the concentration of base, or HC03- due HCl secretion into the stomach lumen) that alkalinized the blood (i.e. caused a rise in pH), a phenomenon known as an alkaline tide. The base load was subsequently removed from the blood through increasedexcretion of base to the water via the gills. In seawater, the commercial diet again provided an avenue for water loss. This was potentially deleterious to an organism already suffering from diffusive water loss to the environment. Ion absorption from the diet was negligible, except for potassium and calcium, which were readily assimilated. As in freshwater, digestion resulted in an alkaline tide, however the mechanism of acid-base homeostasis differed with the excess base likely being excreted into the intestine. In contrast to freshwater fish, the gills took up additional base from the external environment, prolonging the acid-base disturbance in seawater fish. Overall, feeding was a dynamic process with far reaching systemic physiological effects. The research described highlighted intimate interactions between the processes of feeding and digestion and ion, water and acid-base homeostasis, and elucidated mechanisms that enable fish to inhabit a wide range of environments. / Thesis / Doctor of Philosophy (PhD)

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Microbial, mammalian and plant cells produce and contain secondary metabolites, which typically are soluble in water to prevent cell damage by crystallization. The formation of ion pairs, e.g. with carboxylic acids or mineral acids, is a natural blueprint to keep basic metabolites in solution. It was aimed at showing whether the mostly large carboxylates form soluble protic ionic liquids (PILs) with basic natural products resulting in enhanced aqueous solubility. Furthermore, their supramolecular pattern in aqueous solution was studied. Thereby, naturally occurring carboxylic acids were identified being appropriate counterions for natural basic compounds and facilitate the formation of PILs with their beneficial characteristics, like improved dissolution rate and enhanced apparent solubility. / Mikrobielle, Säugetier- und Pflanzenzellen produzieren und enthalten Sekundärmetaboliten, welche in Wasser gelöst vorliegen, um Zellschäden (z.B. durch Kristallisation) zu vermeiden. Die Bildung von Ionenpaaren, beispielsweise mit Carbonsäuren oder Mineralsäuren, ist eine natürliche Strategie, um basische Metaboliten in Lösung zu halten. Es sollte gezeigt werden, dass die vergleichsweise großen Carboxylate lösliche protische ionische Flüssigkeiten (PILs) mit basischen Naturstoffen bilden, was zu einer verbesserten Wasserlöslichkeit führt. Weiterhin wurde das supramolekulare Verhalten der PILs in wässriger Lösung untersucht. Dabei wurden natürlich vorkommende Carbonsäuren als geeignete Gegenionen für natürliche basische Verbindungen identifiziert. Die resultierenden PILs zeigten eine verbesserte Auflösungsrate und verbesserte scheinbare Löslichkeit.