Room temperature ionic liquids (ILs) are a unique class of solvents which are characterized by non-volatility, non-flammability, electrochemical stability and high ionic conductivity. These properties are highly desirable for ion-conducting electrolytes, and much work has focused on realizing their application in practical devices. In addition, hydrophilic and ionophilic polymers are generally miscible with ILs. The miscibility of ILs with ion-coordinating polymers makes ILs effective plasticizers for gel polymer electrolytes. Due to their unique properties, ILs present a means to realize the next generation of energy storage technology. In this dissertation, the fundamental interactions between poly(ethylene oxide) (PEO) and a variety of room temperature ILs were investigated. ILs with acidic protons were demonstrated to form a stronger interaction with PEO than ILs without such protons, suggesting that hydrogen bonding plays a dominant role for PEO miscibility with ILs. The hydrogen bonding interaction is selective for the PEO block of a PEO-b-PPO-b-PEO block copolymer (BCP). Therefore, blending these copolymers with the strongly interacting IL 1-butyl-3-methylimidazolium hexafluorophosphate ([BMI][PF6]) induced microphase separation into a well-ordered structure, whereas the neat copolymer is phase mixed. At sufficient quantities, the interaction between [BMI][PF6] and PEO suppresses PEO crystallinity entirely. In addition, the induced microphase separation may prove beneficial for ion conduction. Therefore, microphase separated copolymer/IL blends were investigated as potential gel polymer electrolytes. Cross-linkable block copolymers which microphase separate when blended with [BMI][PF6] were synthesized by modifying PPO-b-PEO-b-PPO copolymers with methacrylate end-groups. Cross-linking these copolymers while swollen with an IL generates ion gels with high ionic conductivities. The copolymer/IL blends vary from a well-ordered, strongly microphase separated state to a poorly ordered and weakly microphase separated state, depending upon the molecular weight. Stronger microphase separation results in higher mechanical strength upon cross-linking. However, this does not greatly affect ion conductivity. Nor is conductivity affected by forming gels from cross-linked PEO homopolymers when compared to BCPs. It was found that BCPs can be beneficial in producing gel electrolytes by allowing sequestration of phase selective cross-linkers away from the conducting block. Cross-linker molecules that are selective for the PPO blocks can be used to increase the mechanical strength of the gels with only a small effect on the conductivity. When cross-linkers that partition to the mixed PEO/IL block are used, the conductivity decreases by nearly a factor of 2. These studies show how ILs interact with PEO and how gel polymer electrolytes can be constructed with the IL [BMI][PF6]. While BCPs cannot directly be used to increase ion conductivity, they do allow for greater mechanical strength without sacrificing conductivity. This suggests many new approaches that may be used to simultaneously achieve high ionic conductivity and mechanical strength in solid and gel polymer electrolytes.

Electrode microstructure influences ionic transport and electronic transport and is a key factor that affects lithium-ion battery performance. Non-uniform microstructure or heterogeneity in battery electrodes has long been observed and leads to non-uniform transport properties. This work provides a better understanding of in-plane heterogeneity at millimeter length scale and through-plane heterogeneity at micrometer length scale, through a combination of experiment and modeling. The first part of this work develops the aperture probe technique, which is an experimental method and associated model to locally estimate ionic transport, represented by MacMullin number, in the electrode. By generating contour maps of MacMullin number, the in-plane variation of ionic transport is visualized in the electrodes. The local ionic transport measurement technique is validated by comparing with another measurement technique and showing an agreement between the results obtained from the two techniques. The second part of this work focuses on characterizing dual-layer anodes that consist of two layers of coating with distinctly different microstructures. The aperture probe technique was adapted to determine the MacMullin numbers in the two layers separately. The method was validated by a series of virtual experiments and by comparing in one case to an electrode film that was delaminated from the current collector and experimentally sampled from both sides. Because both the electronic transport and the ionic transport are found to be related with the electrode microstructure, it is of interest to understand how these two transport properties relate to each other. The local electronic conductivity and MacMullin number of several commercial-grade electrodes were mapped. The correlation between the two transport properties is distinct for each electrode and significant at length scales larger than about 6 mm. The last part of this work investigates how heterogeneity of ionic transport affects the cycling performance of a lithium-ion cell. A localized MacMullin number measurement is made to characterize the ionic transport heterogeneity of electrodes prior to cycling. Then synchrotron-based X-ray diffraction is applied to analyze the heterogeneity in state of lithiation after high-rate cycling. When comparing the ionic transport map and the state-of-charge map, no strong correlation is observed. While this experiment was inconclusive, it suggests that other factors are more responsible for spatial variations in state of lithiation.

<p> This thesis describes the ionic strength and ion binding effects on the oxidation reduction properties of cytochrome c and its lysine modified derivatives.</p> <p> Cytochrome c has been modified in two different ways: a complete modification of all lysine residues and specific modification of one lysine residue. Some properties of the modified derivatives are described.</p> <p> Ion binding properties of cytochrome c and its lysine modified derivatives were studied by measuring the apparent equilibrium constant of the reaction between the ferri- form of the protein and potassium ferrocyanide. It was found that unmodified cytochrome c binds one cation (K+, Na+) per molecule, and binding is much stronger to the reduced form of the protein. Binding of cations is not changed upon modification of the lysine residues. For binding of the chloride, there are two binding sites on the cytochrome c molecule, and the binding is much stronger to the oxidized form of the protein. It was shown that upon the modification of the lysine residues in either way the binding of chloride was considerably changed. It was concluded that one of these two binding sites for chloride on cytochrome c involves lysine residue, probably the residue number 13.</p> / Thesis / Master of Science (MSc)

Electrically controllable solid propellants are an area of interest as a viable solution to the lack of throttle-ability in solid propellant rocket motors. Existing studies have focused on propellants compositions using hydroxyl-ammonium nitrate, ammonium nitrate, or lithium perchlorate as oxidizers. Additionally, the thermochemical and electrochemical reaction mechanisms have not yet been fully defined. The research in this thesis explores the nitrate and perchlorate oxidizer families to compare their cation-anion relationships. Using these oxidizers, pseudo electrically controllable solid propellant compositions were created with the addition of multi-wall carbon nanotubes to enhance ohmic heating capabilities. These additives were selected based on theory that with a non-complexing polymer, an oxidizer melt layer is required for ions to dissociate and electrically controlled ignition to occur. Using an applied voltage, ignition delay and current draw experiments were performed to expand on prior findings that ignition delay follows oxidizer melt temperature while mobility is associated with the size of the ionic radii. Additionally, neat oxidizer pellets were electrically decomposed to determine their linear regression rate. These results help to characterize the mechanism of reaction. This advances the knowledge of oxidizers in electrically controllable applications. / Master of Science / Solid propellant rocket motors have been extensively studied and used in both space and military applications because they do not use air as the source of oxygen. Their main limitation is the lack of throttle-ability, or inability to control propellant burning. This is because solid propellants, which are generally composed of an ionic oxidizer salt, a polymer fuel, and additives, are pre-combined and stored within the rocket motor. An emerging viable solution to this limitation is electrically controllable solid propellants. With an applied voltage, the oxidizer is heated and melts, allowing ions to dissociate and current to flow between electrodes. This reaction can then be controlled by turning the power supply on and off. Cations, or ions which have a net positive charge, move to the negatively charged cathode while anions, which have a net negative charge, move to the negatively charged anode. The research in this thesis explores different cation-anion oxidizer pairings using both a propellant composition and as a pure oxidizer under an applied voltage. The results help to characterize the mechanism of reaction of each oxidizer in an electrically controllable context and determine their effectiveness in these propellant applications.

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