- 學位論文
磺酸化二氧化矽奈米纖維複合膜於燃料電池上之應用
Sulfonated silica nanofiber-Nafion composite membranes for fuel cell applications
摘要
本研究利用溶膠-凝膠法（Sol-gel method），輔以靜電紡絲技術製備二氧化矽奈米纖維（SNF），再經磺酸化改質流程，製備磺酸化改質之二氧化矽奈米纖維（SNF-SO3H），並與Nafion 全氟磺酸化高分子混摻，以重鑄法製備成具有良好分散性之質子交換複合膜，探討此複合膜之各項特性與其在燃料電池之應用。 由結果顯示添加磺酸化改質二氧化矽奈米纖維在質子交換複合膜內能提升其質子傳遞能力及保水能力。表現最佳之複合膜為含3wt% SNF-SO3H之N-S-3，其保水率（Water uptake）可達約32.5％ ，質子導電度為7.37×10-3 S/cm，相較於未添加任何磺酸化改質二氧化矽奈米纖維的Nafion重鑄模(RN)（5.18×10-3 S/cm）亦有一定程度的提升。 此外，本研究所製備之複合膜應用在質子交換膜燃料電池之單電池（PEMFC）效能測試結果顯示，操作氣體為H2(g)/O2(g)，在TH2/Tcell/TO2=50/50/50℃及加濕環境下，以NS3製備之NS3FC單電池之效能最佳，在電壓為0.4V時，功率密度為761 mW/cm2， 比RN製備之RNFC單電池效能提高了23.9%；而在TH2/Tcell/TO2=50/50/50℃及乾燥環境下其功率密度仍可達到539 mW/cm2； 另外，在TH2/Tcell/TO2=50/80/50℃及乾燥環境下RN製備之RNFC單電池已無法取得電池效能，但NS3FC之功率密度則仍有346 mW/cm2。此研究結果顯示， 磺酸化改質二氧化矽奈米纖維之添加可提高Nafion質子交換膜之效能，是很有潛力之添加劑。
並列摘要
In this study, the silica nanofiber （SNF） was prepared via the sol-gel polymerization by the electrospinning method. Then SNF was sulfonated to prepare the sulfonated silica nanofiber （SNF-SO3H）。The silica nanomaterials were used as a filler to produce the corresponding composite membranes by blending with Nafion. The performance of the proton exchange membrane fuel cells with the composite membranes were studied and compared to that with the recast Nafion membrane（RN）. The as-prepared silica nanomaterials were characterized by FT-IR, TGA, SEM,29 Si-solid state, NMR and SEM measurements. The properties of the composite membranes were investigated by their proton conductivity,water uptake and ion-exchange capacity. The best properties were obtained from the composite membrane NS3, which contained 3wt% of SNF-SO3H. It exhibited 32.5％ of water uptake and 7.37×10-3 S/cm of proton conductivitythat were both higher than RN. In addition, the performance of the PEMFC with the as-prepared composite membrane were also tested with H2/O2 gases. The best performance single cell was obtained from NS3FC, the PEMFC fabricated with NS3. Under the humidified condition and TH2/Tcell/TO2=50/50/50 its power density was 761 mW/cm2, which was 23.9% higher than RN, and under dry condition and TH2/Tcell/TO2=50/50/50℃,the power density was 539 mW/cm2, Besides, under dry condition and TH2/Tcell/TO2=50/80/50℃ it was unable to measure the power density for the RN-base FC, while NS3FC exhibited 346 mW/cm2 of the power density. The results indicate that the as-prepared sulfonated silica nanofiber was potential filler for Nafion as a proton exchange membrane for PEMFC.