- 期刊
小分子塑化PEO高分子電解質之製備與特性分析
Preparation and Characterization of Plasticized PEO Polymer Electrolytes
摘要
本文操用小分子摻合法，降低PEO高分子電解質的結晶性，以提高其導電度並保持良好的界面穩定度與尺寸安定性。結果顯示，以4-tert-butylcatechol摻合約可降低PEO之結晶度至30%為最有效，其次為catechol之50%。測量此系列電解質室溫下之阻抗，可求得其導電度，結果亦顯示以4-tert-butylcatechol摻合可提昇PEO之離子導電度約五倍，約為2x10^(-5) S/cm。調整其與PEO之莫耳數比，可見在低濃度時其離子導電度隨摻合量增加而增加，而摻合比達到重量莫耳濃度1.11m時即不再改變。以本實驗室合成之醚類高分子2來作摻合實驗，結果顯示摻合濃度僅為0.33m時，離子導電度即已高達1.1x10^(-5) S/cm，當摻合此高分子之單體1於PEO中時，摻合濃度為1.67m時離子導電度亦高達2.1x10^(-5) S/cm，皆優於4-tert-butylcatechol。在介面穩定度方面，多次反覆量測摻合電解質薄膜之阻抗可得Nyquist圖譜，發現含有-OH官能基或醚基類之小分子摻合入PEO中，於通入電流後易滲出電解質表面，並導致其界面的相對穩定性降低。以4-tert-butylcatechol摻合之電解質雖可維持離子導電度不變，但是其系統界面阻抗卻隨量測次數而逐漸增加，同樣的情形亦發生在單體化合物1摻合之系統，證明此兩摻合電解質系統皆相當不穩定，但以具醚基分子鏈高分子2來摻合時，電解質系統的化學穩定性卻相當良好，此現象應與摻合體之擴散速率有關。這些結果顯示此聚醚基高分子2應具備作為鋰電池優良電解質材料之深厚潛力。
並列摘要
A series of selected molecules were blended into polyethylene oxide (PEO) to be used as solid electrolyte in.secondary lithium batteries. It was found that 4-tert-butylcatechol was the most effective for reduction of crystalinity as well as for enhancement of ionic conductivity, however, it was not very stable upon repeated impedance measurements due to leakage at interfaces. Polymer 2 containing hydroquinone with triglyme pendants was prepared from 1 by ring-opening metathesis polymerization process. The PEO material blended with about 2% of 2 showed a significant improvement on conductivity compared with pure PEO. This new material was also showed higher stability than other blended molecules on repeated a.c. impedance measurements. A comparison on crystalinity, ionic conductivity, and relative stability for all blended PEO materials is discussed.