改質型聚矽氧烷高分子電解質鋰離子傳導機制分析及其電池應用之研究

Investigation of lithium ionic transfer mechanism of modified polysiloxane electrolyte and its application in battery

王復民(Fu-Ming Wang)

指導教授 ： 萬其超 ； 王詠雲

國立清華大學/工學院/化學工程學系/博士(2009年)

摘要

近年來由於鋰電池爆炸案例層出不窮，因此如何去開發出具有高安全特性及高效率的電池是當務之急的事。然而使用高分子作為鋰電池內之電解質可以解決並有效改善此一問題，另外使用聚矽氧烷系列之高分子作為電解質也可改善長久以來高分子與電極接觸性較差的問題在本此篇論文研究中，我們開發出三種新型固態高分子電解質，並且在文中探討其氧烷基側鏈長度對於物理特性及與電極接觸能力的改善。除此之外，此種新型電解質也具有相當好的熱穩定特性並其中之一的高分子電解質(polysiloxane 3)具有相當高的室溫離子導電度1.15×10-4 S/cm。利用電化學儀器分析發現氧烷基側鏈的長度將有助於鋰離子傳導，另外也從正子消散圖譜發現高分子自由體積與側鏈官能基的關係，進行解析出鋰離子在高分子鏈中運動的情形。電解質應用於電池中的情形也於此篇論文中加以詳述，我們發現不但可以順利進行充放循環測試之外，對於使用不同種的電極材料下的電壓區間也可以保持一定的電容量，但是對於與使用液態電解液之電池性能仍還有一段道路要努力！ 最後在本文也利用正子能階圖譜分析不同種電解質於放電後電極材料上的離子傳導研究，我們發現使用液態電解液與高分子電解質的具有完全不同的離子傳導；並且也發現氧烷基側鏈的效應也具一定程度影響了離子傳導之路徑方式，所有
的詳細研究成果呈現於本內文中。

關鍵字

聚矽氧烷 ； 離子傳導 ； 電化學 ； 正子消散 ； 鋰電池 ； 高分子電解質

並列摘要

In view of recent explosions of lithium ion batteries, it is important matter to make the safer and higher efficient lithium ion batteries. The polymeric electrolytes would likely to be important materials for solving these types of problems. In addition, the normal problem occurs for polysiloxane electrolyte is duo to their electrode contact ability property and without viscidity property.
In this research, there are the novel three types of solid polymer electrolyte of the hydrophobic-hydrophilic modified siloxane being successfully prepared. We also discussed about the effect and relationship between the length of EO (ethyl oxide)side group and physical properties like electrode contact ability. As for the conductivities, the ionic conductivity of modified polysiloxane 3 could reach ca 1.15×10-4 S/cm at 25℃. We discussed about the electrochemically behavior and the EIS properties effect and relationship between the length of EO (ethyl oxide) side group at room temperature in this research. As expect, we also determined the free volume to the three types of polymer electrolytes and found the relationship between polymer structures which is EO dominated at room temperature and environmental temperature dependent. The battery performance of modified polysiloxane 3 is also assembled with LiCoO2 and LiFePO4 to a half cell testing. Furthermore, we discussedabout the possible ionic transfer behavior by PAS technique and the impedance properties effect and relationship between the length of EO (ethyl oxide) side groupand carbonate liquid electrolyte at room temperature. The impedance measurement had been confirmed the results from PAS and make its clear.

並列關鍵字

polysiloxne ； ionic transfer ； electrochemistry ； positron annihilation ； lithium battery ； polymer electrolyte

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