本研究中製備出對稱/非對稱兩種不同孔洞型聚苯咪唑高分子薄膜應用於高溫質子交換膜燃料電池進行測試。使用的高分子為六氟化聚苯咪唑，並使用 dibutyl phthalate 和 1-ethyl-3-methylimidazoliumbis(trifluoro-methylsulfonyl)imide ([EMIM][TFSI]) 為孔洞劑，以軟模板的方式成功製備出對稱/非對稱兩種不同孔洞型聚苯咪唑高分子質子交換膜。多孔性結構成功幫助聚苯咪唑薄膜提升50 %磷酸摻雜量。然而，多孔性結構有可能會造成磷酸流失和燃料穿透等問題，造成燃料電池的效能以及耐用度大幅下降。為了克服這些缺點，本研究中製備出非對稱性孔洞薄膜。此非對稱性孔洞薄膜包含緻密層與孔洞層，希望藉由孔洞層提升磷酸的摻雜量的同時也藉由緻密層來解決磷酸流失和燃料穿透等問題。兩種多孔性薄膜皆進行機械強度、熱穩定性、抗氧化性、質子導電度等質子交換膜性質相關測試，藉由掃描式電子顯微鏡觀察多孔性薄膜的表面及斷面型態，紀錄孔洞大小以及分布。單電池測試方面，以開關測試 (150 °C下負載0.2 A/cm2 12小時後再停止負載並將溫度降至室溫) 進行單電池性能初步評估，之後再進行三十天的長時間穩定度測試 (150 °C下負載0.2 A/cm2 720小時)。測試結果對稱/非對稱兩種不同孔洞型聚苯咪唑高分子質子交換膜在單電池開關測試方面皆表現良好，最高功率密度可以達到600 mW/cm2以上。三十天的長時間穩定度測試中發現，非對稱性孔洞結構可以解決酸流失問題，相對於對稱性孔洞薄膜大幅提升了燃料電池的耐用度。

In this work, two different types of porous polybenzimidazole (PBI) membranes, symmetrically and asymmetrically porous membranes, were successfully fabricated and tested for high temperature proton exchange membrane fuel cells (HT-PEMFCs). The hexafluoroisopropylidene containing PBI (6FPBI) was used and the symmetrically and asymmetrically porous membranes were prepared by soft-template method with two kinds of porogens; they were dibutyl phthalate and 1-ethyl-3-methylimidazoliumbis(trifluoro-methylsulfonyl)imide ([EMIM][TFSI]), respectively. The morphologies of the porous membranes were checked by SEM. The physicochemical properties required for HT-PEMFC such as doping level, proton conductivity, mechanical strength and oxidative stability have been studied. The porous structure successfully helps the PBI membranes to uptake more phosphoric acid and increase the proton conductivity about 50 %. However, the porous structure might cause the problems like acid leakage or fuel crossover. To overcome these problems, the asymmetrically porous structure were introduced. The startup/ shutdown tests (12 h on at 150 °C with 200 mA cm-2 and 12h off at room temperature) and long-term durability tests (720 h at 150 °C with 200 mA cm-2) were conducted. The maximum power density of symmetrically and asymmetrically porous PBI membranes was 624 and 616 mW cm-2 at 150 °C, respectively. In the long-term durability tests, the asymmetrically porous structure did significantly reduced the phosphoric acid loss and increased the durability of the fuel cell compared to the symmetrically porous structure.

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