新穎性高效能複合質子交換膜應用於燃料電池之製備與性質研究 1. Nafion/磺酸化中孔洞雙矽源二氧化矽複合質子交換膜 2. Nafion/具孔洞性配位高分子複合質子交換膜

Application and Properties of the Novel Composite Membranes on PEMFC 1. Nafion/Mesoporous Sulfonated Silica Composite PEM 2. Nafion/Porous Coordination Polymer Composite PEM

蔡政修(Cheng-Hsiu Tsai)

指導教授 ： 陳玉惠

中原大學/理學院/化學研究所/博士(2012年)

https://doi.org/10.6840/cycu201201077

摘要

本研究主要利用不同之孔洞性材料，如改質之中孔洞二氧化矽或具孔洞性之配位高分子，利用其自身不同的保水特質，製備出具新穎高性能之複合質子交換膜，將其應用於高溫或乾燥環境下之質子交換膜燃料電池。以下分成兩部分做討論：

Part Ⅰ. Nafion/磺酸化中孔洞雙矽源二氧化矽複合質子交換膜

本部分之研究以雙矽源系統與離子熔液，利用溶膠-凝膠法製備中孔洞二氧化矽，再經磺酸化改質，製備磺酸化改質之中孔洞二氧化矽。並以其作為添加物導入至Nafion高分子中，以重鑄法製備具良好分散性之複合質子交換膜，應用於質子交換膜燃料電池中，探討其對單電池效能之影響。
由結果顯示添加磺酸化改質中孔洞二化矽在複合質子交換膜內可有效地提升其保水能力、質子導電度。最高之保水率(Water uptake)可達約60 wt.%、最佳之質子導電度為1.29×10-2 S cm-1 ，優於未添加任何二氧化矽的Nafion重鑄(RN)膜(4.63×10-3 S cm-1)。單電池效能測試結果，本研究中以FC-7(N/3SS1)之單電池有最佳的效能展現。其在65 °C、全加濕環境下之最佳功率密度為1072 mW cm-2，比FC-0(RN)高出47 %；在65 °C、全乾燥環境下之最佳功率密度可達414 mW cm-2，優於FC-6(N/3PS1)4倍之多。

Part Ⅱ. Nafion/具孔洞性配位高分子複合質子交換膜

本部分之研究成功以六種不同之配位高分子為添加物，並將其導入Nafion高分子中，以重鑄法製備應用於燃料電池且具良好分散性之複合質子交換膜，探討配位高分子其對單電池效能展現之影響。由結果顯示，配位高分子材料內之分子結構若具有未飽和金屬位置、對水吸附之作用力(氫鍵或路易士酸-鹼作用力等)、表面孔洞之特性，將有助於將水分子吸附並維持在其孔洞或孔道內。複合膜之保水率(Water uptake) 可以提升至27~40 wt.%。質子導電度以PEM1與PEM4複合膜有最佳之質子導電度(9.72×10-3 S cm-1與6.62×10-3 S cm-1)，優於未添加任和配位高分子的RN膜(5.10×10-3 S cm-1)。單電池效能測試結果，50 °C、全加濕環境，FC-2之單電池最佳功率密度為818 mW cm-2，比FC-0(RN)高出83%；在80 °C、全加濕環境，FC-2之單電池最佳功率密度為591 mW cm-2，比FC-0(RN)高出92%；在50 °C、80 °C(全乾燥環境)下之最佳功率密度仍可達853 mW cm-2、568 mW cm-2。另FC-4於50 °C、全加濕環境之效能為669 mW cm-2。此配位高分子材料具可應用於乾燥或有加濕的高溫環境下使用之潛力。

關鍵字

Nafion複合膜 ； 磺酸化二氧化矽 ； 配位高分子 ； 質子交換膜燃料電池 ； 金屬-有機骨架材料

並列摘要

PART Ⅰ. Nafion/Mesoporous Sulfonated Silica Composite PEM

In this study, the mesoporous phenyl-silica (PS) was synthesized with tetraethoxysilane (TEOS) and phenyltriethoxysilane (PTES) as the Si-precursors. Then PS was sulfonated by the simple sulfonation with concentrated sulfuric acid to prepare the mesoporous sulfonated phenyl-silica (SS). The Nafion-based nanocomposite membranes, N/PS and N/SS, were successfully prepared with PS and SS silicas, respectively, and used as PEM for preparation of the PEMFC single cells.
It was found that the introduction of mesoporous sulfonated phenyl-silica to the Nafion membrane effectively improved the water-retention ability and proton conductivity of membranes. The highest value of water uptake was up to about 60 wt.% and the best proton conductivity was about 1.29×10-2 S cm-1, which were both higher than that of recast Nafion membrane (RN). The PEMFC single cell fabricated with N/3SS1 (FC-7) had the best cell performance and its power density was 1072 mW cm-2 at 65 °C under the humidified condition, which was approximately 47% higher than that with FC-0 (RN). Besides, the peak power density obtained at 65 °C under dry condition was 414 mW cm-2, which was approximately 4 times higher than that of FC-6 (N/PS1).

Part Ⅱ. Nafion/Porous Coordination Polymer Composite PEM

In this study, six porous coordination polymers (CPs) have been first time used as fillers to prepare the novel Nafion-based composite membranes (N/CPs) as proton exchange membranes (PEMs) for proton exchange membrane fuel cells (PEMFCs).
It was found that compared to that of the recast Nafion membrane (RN), the water uptakes and the highest proton conductivity of N/CPs were improved for 1.5-2.4 times and 4.62 mS cm-1. Under the humidified condition, the best power density of the N/CP-based PEMFC single cell fabricated with Nafion and CPO-27(Mg) measured at 50 °C and 80 °C was approximately 74% and 92% higher than that with the RN membrane, respectively. Besides, the peak power density obtained at 50 and 80 °C under dry condition were 853 mW cm-2 and 568 mW cm-2, respectively. On the other hand, the power density of FC-4 obtained at 50 °C and under the humidified condition is 669 mW cm-2. The improvements were mainly ascribed to the water retention ability of the CP fillers caused by the pore structure, amount of the coordinated water and interactions between the unsaturated metal sites and water molecules This study suggests that the porous CPs with high water retention are new potential fillers for PEM.

並列關鍵字

Sulfonated silica ； Nafion composite membrane ； Coordination polymers ； Metal-organic framework ； PEMFC

參考文獻

[13]本間琢也、上松宏吉，燃料電池：連北極熊都說讚的替代能源！，瑞昇文化事業股份有限公司，2011 年10 月。

[49]吳千舜、諸柏仁，燃料電池質子交換膜的最新發展，Chemistry (The Chinese Chem. Soc., Taipei)，62 (1) (2004) 123-138.

[1] Y. L. Liu. Developments of highly proton-conductive sulfonated polymers for proton exchange membrane fuel cells. Polym. Chem. 3 (2012) 1373-1383.

[2] M. Hashem Nehrir, Caisheng Wang. Modeling and control of fuel cells: distributed generation applications. Hoboken, N.J.: Wiley, 2009.

[3] M. M. Mench. Fuel cell engines. Hoboken, N.J.: John Wiley & Sons, 2008.