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Room temperature molten liquids are proposed to be good alternates for volatile and harmful organic compounds. They are useful in varied areas of applications ranging from synthesis, catalysis to energy storage molten electrolytes have certain unique characteristics such as low vapour pressure, reasonably high ionic conductivity, high thermal stability and wide electrochemical window. These molten liquids can be classified in to two types depending on the nature of the species present in the liquids. One, those liquids consists only of ions (e.g) conventional imidazolium based ionic liquids and other that consists of ions and solvents (e g) acetamide eutectics. Acetamide and its eutectics from room temperature molten solvents that is unique with interesting physicochemical properties. The solvent properties of molten acetamide are similar to water, with high dielectric consist of 60 at 353 k. its acid – base properties are also similar to water, and it can solublise variety of organic and inorganic compounds as well. in the present studies room temperature molten liquids consisting of acetamide as one of the components have been prepared and used for various applications. Room temperature molten electrolytes consisting of magnesium perchlorate/magnesium triflate as one of the constituents have been used for rechargeable magnesium batteries where as those consisting of zinc perchlorate /zinc triflate have been used for zinc based rechargeable batteries. Full utilization of cathode material (y-mno2) is achieved using amide-based molten liquid as electrolyte in rechargeable zinc based batteries. Ammonium nitrate/ lithium nitrate containing electrolytes have been used for electrochemical super capacitors. They have been used as solvent cum stabilizers for metallic nanochains that can be used as substrate in surface enchanced Raman scattering studies.

Battery is the sole electrical energy source when electric vehicle(EV) is moving. To reduce traveling anxiety, an effective energy management system to indicate the state-of-charge (SOC) of the battery and make a balance between vehicle performance and endurance is very important. This research is aimed to develop a SOC estimation system with high accuracy. The proposed method in this thesis is based on under load voltage and multilevel Peukert's equation to estimate the SOC. The proposed method is compared with the open circuit voltage method for initial SOC estimation and with coulometric method for cumulative SOC estimation under various EV driving conditions simulated by an adjustable electronics load. Experimental results indicate that the proposed method can provide reasonable accuracy as compared with other tested methods for LiFePO4 battery SOC estimations.

Thesis (M.S.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains x, 165 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 163-165).

Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references. Available also from UMI Company.

published_or_final_version / Electrical and Electronic Engineering / Master / Master of Philosophy

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The aim of this thesis is to develop a better understanding about the degradation mechanisms occurring within lithium-ion cells which eventually lead to their failure. An introduction to the components and operation of Li-ion cells is followed by proposed degradation mechanisms which limit the lifetime of cells. These mechanisms and how they can be identified from electrochemical testing are discussed. Electrolyte additives can be used to improve the safety of Li-ion cells or decrease the rate of cell degradation. Different types of additives and testing methods are discussed followed by an introduction to high precision coulometry which can be used to detect the impact of additives on cycling performance. The High Precision Charger that was constructed for this project is described and shown to meet the desired precision. The use of additives and different materials to extend lifetime of cells is shown to be detectable through the use of high precision coulometry. High precision coulometry proves to be a more efficient way of estimating the lifetime of cells under realistic conditions in a reasonably short amount of time. / MSc. Thesis

In order for battery manufacturers to have a sustainable business, the batteries they produce must be as safe as possible. For lithium-ion batteries, reducing the flammability of the electrolyte is considered to be one way to improve safety, which might be achieved by adding flame retardants to the electrolyte. On the other hand, sodium-ion batteries are attracting attention from academic researchers due to the abundance of sodium reserves compared to lithium reserves. However, there are virtually no studies about the safety of sodium-ion batteries. In this thesis, studies of these two issues will be reported. The reactivity of charged/discharged electrode materials for sodium-ion batteries in different solvents and electrolytes at elevated temperature was studied using Accelerating Rate Calorimetry (ARC). Hard carbon was studied as a negative electrode material for sodium-ion batteries. The reactivity of sodium-inserted hard carbon in solvents and electrolytes was investigated. Then, the reactivity of sodium-inserted hard carbon was compared to lithiated graphite. NaCrO2, NaxCoO2 and NaNi0.5Mn0.5O2 were studied as positive electrode materials for sodium-ion batteries. The electrochemical performance of these materials was investigated. The reactivity of charged NaCrO2, NaxCoO2 and NaNi0.5Mn0.5O2 in solvents and electrolytes was studied using ARC. Sodium bis(trifluoromethanesulfonyl)imide (NaTFSI) was studied as an electrolyte salt for sodium-ion batteries. The electrochemical performance of hard carbon and NaCrO2 in NaTFSI/PC electrolyte was studied. The reactivity of sodium-inserted hard carbon and deintercalated NaCrO2 in NaTFSI/PC electrolyte was also investigated. Triphenyl phosphate (TPP) was studied as a flame retardant additive for lithium-ion batteries. Its impact on electrochemical performance of negative electrode materials (petroleum coke and graphite) and positive electrode materials (LiNi1/3Mn1/3Co1/3O2 (NMC) and LiNi0.8Co0.15Al0.05O2 (NCA)) was studied using an automated storage test, symmetric cells and Electrochemical Impedance Spectroscopy (EIS). The reactivity of lithiated graphite, deintercalated NMC and NCA in electrolyte containing TPP was investigated using ARC. Finally, the flammability of electrolytes containing TPP was studied using a Self-Extinguishing Time (SET) test.

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