Optimization of Electrolyte of Dynamic Lithium Ion Battery under Temperature Control using Multinuclear NMR Spectroscopy
| Autor: | Yu-San Lin, 林佑珊 |
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| Rok vydání: | 2015 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 103 Since the 1990s, it is well-noticed that Li+ ion battery is at present in the near future one of the most important power sources. Meanwhile, Li+ ion battery does also exhibit electronic instability drawback. Accompanied with the fast growing requirement of high energy density, the battery becomes more and more volatile and dangerous. It is therefore the improvement of Li+ ion safty to prevent from thermal runaway is always a hot topic in its research. Electrolyte is one of the most impotent parts of the Li+ ion battery. This study focuses on some of the requirements of Li+ ion batteries which involves : firstly, the low temperature electrolyte design (including ion salt type, ion salt concentration, organic solvent composition);second, the interactions between LiPF6 at sealed and room temperature conditions; last, study of three kinds commercial electrolytes diffusion behaviors at temperature between low and high temperature. By the observation of the freezing tests at various composition made of the Diethyl Carbonate (DEC), Ethylene Carbonate (EC), Propylene Carbonate (PC) and various concentration of LiClO4 added, we conclude that if the ratio of lower conductivity component DEC is more than the higher conductivity component EC and with LiClO4 concentration greater than, say, 0.4 molarity, then this kind of electrolytes exist good low temperature character. At room temperature and sealed condition we have solid evidence that even a trace of water will interact with LiPF6 and create the products of LiF, HF, H/LiPO2F2, H2/Li2PO3F. Last, the diffusion coefficient of lithium and phosphorus obvious difference, which means that the lithium ions will be formed of Li+-solvent coordination sphere aggregation in the solvent. And the different anoion of lithium salt for the diffusion coefficient of the impact is not obvious. In the electrolytic solution for lithium salt concentration from about 0.8 to 1.2M. Through the above results, NMR can provide electrolyte behavior in microscopic performance under different temperatures. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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