MEEP及PAN奈米複合高分子電解質之製備、性質及其在鋰二次電池之應用研究

The Preparation, Properties and the Li Rechargeable Battery Application of (1)MEEP-based (2)PAN-based on Nanocomposite Polymer Electrolyte

陳宏昌(Hung-Chang Chen)

指導教授 ： 陳玉惠

中原大學/理學院/化學研究所/博士(2002年)

https://doi.org/10.6840/cycu200200212

摘要

中文摘要
在本研究中製備出一系列以極性基位於側鏈之高分子為主體含α-Al2O3的固態複合高分子電解質，探討適當鋰金屬鹽類及α-Al2O3添加量對於複合高分子電解質導電度及機械性質之影響，並進一步探討影響其與電極間之相容性及其他相關之性質。故本研究首先利用導電度的量測在不同的鋰鹽濃度、不同的α-Al2O3添加比例與不同的溫度情況下，研究各因素與導電度之間的關係其次，以線性掃瞄伏安法(linear sweep voltammetry ,LSV)和循環伏安法(cyclic voltammetry ,CV)測試電解質的電化學穩定性，以FTIR與DSC分析α-Al2O3添加前後對導電度提升的影響，探討離子間的作用力及電子可能之傳導機構。另外，利用XRD鑑定電解質的結晶變化、SEM-EDX觀察表面性質及對特定元素Al作分析，鑑定α-Al2O3是否均勻分散此外，以MTS測試其機械性質及固態27Al、7Li-NMR核磁共振分析鑑定α-Al2O3與鋰離子附近的環境變化。最後，由陽離子傳導係數的量測，進一步了解鋰離子在這些複合高分子電解質傳導角色的變化，由以上實驗結果顯示，本研究所製備之複合高分子電解質主要由鋰離子，而傳導鋰離子的傳導除依靠高分子鏈的運動移動外也藉由添加的α-Al2O3表面提供的Lewis-base centers當”hopping sites”的幫助來傳導。在本研究中已製備出室溫導電度接近10-3S/cm並具備良好機械性質的固態複合高分子電解質，將可與適當之電極製備出具實用價值的鋰二次高分子電池，並期進一步應用在鋰金屬高分子電池之組裝。

關鍵字

鋰二次電池 ； 奈米複合高分子電解質 ； 電化學 ； 固態高分子電解質 ； 離子導電度

並列摘要

Abstract
In this study, usingα-Al2O3 particles as ceramic filler a series of novel solid-type, MEEP-based composite polymer electrolyte (CPE) and a series of PAN-based CPE have been prepared. The effect of the addition ofα-Al2O3 on the conductivity and the related properties of the composite polymer electrolytes are analyzed. The interactions existing in the system and the possible conductivity mechanism revealed by the results of FT-IR spectroscopy, XRD diffraction pattern, solid state 27Al-NMR, 7Li-NMR, t+ and DSC measurement are investigated.
For the MEEP-based CPE, the best conductivity obtained is close to 10-4 S/cm at room temperature from the composite polymer electrolyte with 2.5 wt %α-Al2O3 and 0.2 LiClO4 per polyphosphazene repeat unit, which is the highest reported for the MEEP-based electrolytes. From the results of FTIR spectroscopy, DSC measurement, cation transport number and the temperature dependence of conductivity, an ion transport mechanism in the composite polymer electrolytes is proposed.
For the PAN-based CPE, the best conductivities obtained at room temperature is 5.7×10-4 Scm-1 from the one with 7.5 wt%α-Al2O3 and 0.6 LiClO4 per PAN repeat unit. The stress-strain test result indicates that the membranes prepared possess high yield stress (73 kg cm-2) suitable for serving as separators in the solid-state lithium and lithium ion batteries and high yield elongation (225%) pliable to form good interface with electrodes. Also discussed are the effects of the addition of the ceramics on the interactions in the system and the possible conduction mechanism.

並列關鍵字

ionic conductivity ； electrochemistry ； lithium secondary battery ； solid polymer electrolyte ； nanocomposite polymer electrolyte

參考文獻

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