高分子電解質奈米複合材料之合成與物性研究

Studies on the polymer electrolytes nanocomposites of Synthesis and physical properties

葉偉斌(Wei-Bin Ye)

指導教授 ： 廖建勛

元智大學/工程學院/化學工程與材料科學學系/碩士(2002年)

摘要

本研究以聚氧化乙烯( poly ethylene oxide , PEO )寡聚體ω-Methoxypoly( ethyleneglycol ) phosphates ( PEOPA )插層改質於雙層氫氧化合物( layer double hydroxide , LDH )的無機層材表面，以增加LDH於高分子基材中的相容性及分散性，再與高分子量PEO及過氯酸鋰( LiClO4 ) 於乙睛( acetonitrile )中混合，待去除有機溶劑後，得去層化奈米分散的高分子電解質奈米複合材料，以應用於全固態高分子電解質之二次電池中。擬利用奈米分散無機層材抑制高分子結晶成長，無需可塑劑即可提昇室溫下的離子導電度，並藉由合成設計使無機層材表面帶正電荷以吸引電解質之對應陰離子，亦可大幅提昇鋰離子的傳導性。內容包括探討奈米高分子電解質奈米複合材料之合成與結構特性、PEO高分子結晶型態與離子導電性質之關係，以及比較以交流阻抗分析法( AC-Impedance )及直流極化法( DC-Polarization )所求得之鋰離子遷移係數( transference number )。由XRD的結果顯示，經由改質後的LDH於高分子電解質中呈現完全脫層( Exfoliation )狀態，並且高分子電解質呈現完全非晶( amorphous )狀態。添加10 wt%改質LDH時可獲得最高離子導電度6 ×10-5 S/cm ( 30℃)。在鋰離子傳導方面，LDH表面的正電性質對於鋰離子傳導有著正面的影響，其鋰離子遷移係數隨著LDH的含量而增加。

關鍵字

固態高分子電解質 ； 雙層氫氧化合物 ； 直流極化法

並列摘要

In order to enhance the compatibility and dispersion of layered double hydroxide (LDH) into the poly(ethylene oxide) (PEO) matrix, the layer surface of LDH was grafted with PEO-oligomer by in-situ synthesis. The obtained PEO/LDH nanocomposites mixed with lithium percolate (LiClO4) can be used as all solid-state polymer electrolytes in the secondary lithium batteries. In this research, the preparation of PEO/LDH nanocomposites was performed to study the effect of LDH on the morphology, conductivity, and ion transport of polymer electrolytes. According to the XRD results, the PEO-oligomer modified LDH shows fully exfoliation dispersion in the PEO matrix. The well dispersed LDH layers in PEO/LDH nanocomposites results in an amorphous morphology, which can be attributed to the improvement of ionic conductivity of nanocomposites without any liquid plasticizer. The highest ionic conductivity of 6´10-5 S/cm (at 30℃) occurs at the composition of 10 wt% LDH added. On the other hand, the lithium ion transference number measured by dc polarization in PEO/LDH nanocomposites increases with increasing LDH amounts, which is attributed to the positive-charge characteristics appearing on the surface of LDH layers.

並列關鍵字

solid polymer electrolyte ； layer double hydroxide ； dc-Polarization

參考文獻

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