臺灣博碩士論文加值系統

　　本研究主要是將價格較低的PTFE/Nafion複合膜加以改質，加入無機的四乙基矽烷（tetraethoxysilane，TEOS），製備有機無機PTFE/Nafion-TEOS複合膜，並期望能應用於直接甲醇燃料電池（direct methanol fuel cell，DMFC）上，取代價格昂貴又無法有效阻擋甲醇穿透的Nafion膜材。探討PTFE/Nafion膜使用不同TEOS濃度的無機溶液浸漬處理所製作成PTFE/Nafion-TEOS複合膜的表面結構、膜材成分、熱穩定度和導電度及甲醇穿透性，再和Nafion-117作比較，並且將膜材Nafion117、PTFE/Nafion及PTFE/Nafion-TEOS複合膜製作成膜電極組，在溫度為70℃∼90℃及甲醇進料濃度2M∼5M的條件下，做直接甲醇燃料電池系統的測試，比較其單電池效能和電化學特性。由各項數據顯示TEOS能分散於PTFE/Nafion膜材中，改質後的複合膜導電度較未改質複合膜略低，但能有效的阻隔甲醇的穿透。利用較高濃度TEOS混合液浸漬處理的改質PTFE/Nafion-TEOS複合膜在溫度70℃，甲醇濃度5M條件下的單電池效能及開路電位都較未改質PTFE/Nafion複合膜高。顯示改質後的膜材的確有增加抵抗甲醇穿透的能力。

　　PTFE/Nafion-TEOS（P/N-TEOS） composite membranes were prepared by impregnation PTFE/Nafion composite membrane via sol-gel processing with various concentration of tetraethoxysilane（TEOS）. The surface morphology and chemical structure of the composite membranes were investigated by SEM and FT-IR-ATR. The conductivity and the methanol permeability of the membranes were investigated by AC impedance and gas chromatography（GC）, respectively. The results show that the P/N-TEOS composite membranes had lower proton conductivity than P/N composite membrane and a lower methanol flux.　The direct methanol fuel cell（DMFC）performances and electrochemical properties of membrane electrolyte assembly（MEA）prepared using Nafion117, PTFE/Nafion composite membrane, and PTFE/Nafion-TEOS modified membranes were investigated. The open circuit voltage and the cell performance of MEA prepared from PTFE/Nafion-TEOS modified membranes were better than that prepared from unmodified PTFE/Nafion composite membrane an operating temperature of 70℃ and feed methanol concentration of 5M. The experimental results show that the modification of Nafion/PTFE composite membrane with TEOS reduces not only the proton conductivity but also the permeability of methanol. Thus the should an optimum TEOS content and optimum methanol feeding concentration DMFC operation.

一、前言
1.1 聚四氟乙烯（PTFE）簡介
1.2 Nafion（全氟磺酸樹酯）簡介
1.3 直接甲醇燃料電池（DMFC）
1.4 溶膠-凝膠法（sol-gel reaction）
1.5 有機-無機複合膜於燃料電池上的應用
1.6 研究目的
二、實驗方法
2.1 實驗藥品
2.2 儀器設備
2.3 實驗步驟
2.3.1 PTFE/Nafion/TEOS複合膜製備
2.3.2 SEM觀察PTFE/Nafion及PTFE/Nafion-TEOS複合膜表面形態
2.3.3 PTFE/Nafion複合膜EDX元素分析
2.3.4膜材吸水膨潤比(swelling ratio)
2.3.5 PTFE/Nafion複合膜TGA測定
2.3.6 PTFE/Nafion複合膜DSC測定
2.3.7 FT-IR MicroATR
2.3.8導電度的量測
2.3.9甲醇滲透量測
2.3.10DMFC單電池性能測試
2.4 實驗相關原理分析
三、結果與討論
3.1實驗條件
3.2掃描式電子顯微鏡(SEM)觀察
3.3能量分散性X射線顯微分析(EDX)元素分析
3.4微差掃描熱分析(DSC)
3.5熱重分析(TGA)
3.6 FT-IR MicroATR
3.7導電度的量測
3.8甲醇滲透
3.9DMFC單電池效能測試
四、結論
五、參考文獻

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