在本研究中，我們混合五種具有不同側基改質的纖維素(包含CA、CAP、CTA、EC、HEC)，使用旋轉塗佈法製成薄膜，探討在相同主鏈高分子中，高熵效應對結晶度、吸水性、以及鋰離子在此材料內導電行為的影響。經由XRD繞射分析，我們發現單一成份CA、CAP與CTA結晶度分別為36%、34%及46%。隨著混合成份的數增加，展現顯著的結晶度抑制效果。尤其是二元混合時即可大幅抑制結晶，顯示相同主鏈的高分子在較低的成份數時，可以透過良好的共混性或是側鏈之間的交互作用力，如氫鍵，抑制纖維素聚集形成結晶。n=5時結晶度降至5.6%。纖維素中添加20 wt.%過氯酸鋰時，鋰鹽不會形成結晶，且對高分子的結晶並無顯著影響。單成份電解質離子導電度介於10-12~10-10 S/cm之間，且隨著n增加，導電度有上升的趨勢。在n=5時離子導電度達到1.4×10-9 S/cm，混合不同的纖維素衍生物會增加系統中側鏈官能基的種類，有助於增加分子間的空間，降低離子與聚合物之間的作用力，通過釋放自由離子便於離子跳躍。透過Nernst-Einstein關係我們得到纖維素電解質的有效傳導離子濃度遠低於實際添加的鋰鹽，因此增加自由離子濃度成為提升導電性能的關鍵問題。此外，我們觀察到纖維素電解質會快速吸收水氣，導電度隨著吸水量的增加而呈現兩階段上升趨勢，吸水後導電度最高提升至4×10-4 S/cm。在第一階段中，水分子塑化高分子，同時減少極性官能基對離子的吸引力；在第二階段，透過水分子釋放成對或聚集的離子團，增加系統中的自由離子，以提升離子導電度。
總之，本研究通過分析不同纖維素衍生物混合物的系統，揭示混合效應對抑制纖維素結晶的顯著影響，並且纖維素側鏈之間的氫鍵作用對於促進離子在材料中的傳遞有關。電解質的吸水性會大幅提高離子導電度，然而含水的電解質在應用過程中，必須考量其與電池電極材料的相容性問題，以免引起電極損壞或影響電池的循環壽命等負面影響。

In this study, we blended five cellulose derivatives with different side-chain modifications, including cellulose acetate (CA), cellulose acetate phthalate (CAP), cellulose triacetate (CTA), ethyl cellulose (EC), and hydroxyethyl cellulose (HEC), to fabricate films using spin-coating. Our aim is to investigate the impact of high entropy effect on crystallinity, water absorption, and lithium ion conductivity within materials sharing the same polymer backbone. X-ray diffraction (XRD) analysis revealed that the crystallinity of individual components CA, CAP, and CTA were 36%, 34%, and 46%, respectively. With an increase in the number of mixed components, a significant suppression in crystallinity was observed. Notably, at n=2, crystallization was substantially inhibited, indicating that miscible polymers can effectively disperse at lower component counts. Nevertheless, interactions between side chains, such as hydrogen bonding, reduce the rate of crystallization to avoid cellulose aggregation and crystallization. When n=5, the crystallinity dropped to 5.6%. Adding 20 wt.% lithium perchlorate to the cellulose did not form crystals, nor did it significantly affect the crystallinity of the polymers, suggesting that interplanar distance of crystalline cellulose is much larger than lithium ions, thus having limited impact on the crystallinity of cellulose. The ionic conductivity of the single-component electrolyte ranged between 10-12 to 10-10 S/cm, and showed an increasing trend with the rise in n. At n=5, the ionic conductivity reached 1.4×10-9 S/cm, indicating that blending various cellulose derivatives can promote intermolecular space, reducing the coupling between ions and polymers and facilitating smoother ion hopping by releasing free ions. Through the Nernst-Einstein relation, we found that the effective conducting ion concentration of the cellulose electrolyte is far lower than the actual added lithium salt, thus increasing the concentration of free ions becomes the key issue in enhancing conductivity performance. Furthermore, we observed that the cellulose electrolyte rapidly absorbs moisture, with conductivity showing a two-stage increase as the water content rises, reaching up to 4×10-4 S/cm after absorption. In the first stage, water molecules plasticize the polymer, simultaneously reducing the attractive force of polar functional groups towards ions; in the second stage, water molecules release paired or aggregated ion clusters, increasing the number of free ions in the system to enhance ionic conductivity.
In summary, through the analysis of mixed cellulose derivative systems, this study reveals the significant effect of the mixing effect on suppressing cellulose crystallization, and the role of hydrogen bonding between cellulose side chains in facilitating ion transfer within the material. The water absorption of the electrolyte significantly increases ionic conductivity. However, the compatibility issues with battery electrode materials must be considered in the application of hydrated electrolytes to prevent electrode damage or adverse effects on the battery's cycle life.

摘要 I
Abstract III
致謝 VI
目錄 VIII
圖目錄 XI
第一章 簡介 1
第二章 文獻回顧 3
2-1 纖維素衍生物 3
2-2 高熵高分子 4
2-3 高分子固態電解質 6
2-3-1 固態高分子電解質的特性 6
2-3-2 聚合物電解質離子傳導機制 8
2-3-2 增塑劑作用 10
2-3-4 高熵電解質的發展 11
2-4 電化學阻抗圖譜 (EIS) 14
2-4-1 奈奎斯特圖 14
2-4-2 等效電路 15
2-5 實驗材料 16
2-5-1 醋酸纖維素 16
2-5-2三醋酸纖維素 17
2-5-3 纖維素醋酸鄰苯二甲酸酯 18
2-5-4 乙基纖維素 19
2-5-5 羥乙基纖維素 20
第三章 實驗方法 21
3-1 實驗材料 21
3-1-1 高分子材料 21
3-1-2 鋰鹽 22
3-1-3 溶劑 23
3-1-4 實驗基材 23
3-2 樣品製備 24
3-2-1 除水 24
3-2-1 薄膜製備 24
3-2-2 固態高分子電解質封裝 25
3-3 實驗儀器與量測方法 27
3-3-1 光學顯微鏡 (Optical microscopy, OM) 27
3-3-2 Alpha step 27
3-3-3 X光繞射分析儀 28
3-4-3 電化學阻抗分析儀 30
3-4-4 差式掃描量熱法 30
第四章 結果與討論 32
4-1 固態電解質表面形貌 33
4-1-1 混合纖維素薄膜表貌 33
4-1-2 混合纖維素電解質薄膜表貌 36
4-2 高分子電解質結晶度 38
4-2-1 結晶度計算 38
4-2-2 結晶度分析 40
4-2-3 晶面間距與結晶尺寸 46
4-3離子導電度 47
4-4電解質吸水性 57
第五章 結論 62
第六章 參考文獻 64
附錄 70
附錄一 70
附錄二 71
附錄三 72
附錄四 72

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