【作者】 赵静；

【导师】 车全通；

【作者基本信息】 东北大学 ， 物理化学， 2021， 硕士

【摘要】 燃料电池是一种高效的能量转换装置,符合当下人们对可替代能源的切实需求。其中,质子交换膜燃料电池具有能量转化率高、运行温度低以及启动速度快等优点,在新能源汽车领域有着巨大应用潜力。质子交换膜作为燃料电池的主要组成部件,其主要作用是传输质子并阻隔阳极和阴极的燃料直接接触。杜邦公司生产的Nafion?系列膜是目前应用最广泛的质子交换膜。Nafion?系列膜传输质子的过程依赖水分子的参与。在一些气候寒冷的地区,冬季的室外温度通常低于零摄氏度。水结冰会导致Nafion?系列膜无法正常工作,因此开发具有优良的稳定性、导电性以及机械性能的低温质子交换膜,以提升燃料电池在低温环境中的性能是十分必要的。本论文以探索性能优良的质子交换膜为核心,第二章基于聚乙烯醇(PVA),凯夫拉纳米纤维(Kevlar)以及氧化碳纳米管(OCNTs),通过真空辅助絮凝技术制备了(PVA/Kevlar/OCNTs)3/PA复合膜。该复合膜具有有序的层状结构,且组分的分子间可以形成氢键,构建的氢键网络为质子传输提供了更多通道,实现了零摄氏度以下的高效质子传导。在-30℃和30℃下,(PVA/Kevlar/OCNTs)3/85%PA复合膜的质子电导率分别为2.17×10-2 S/cm和1.71×10-1 S/cm。另外,经过-30℃～30℃的十次循环电导率测试后,在-30℃和30℃下,复合膜的电导率分别为5.52×10-2 S/cm和1.84× 10-1 S/cm;在-30℃下,经过1900小时的测试后,复合膜的电导率保持在1.42× 10-2 S/cm。另外,(PVA/Kevlar/OCNTs)3/85%PA 复合膜在 160℃下的电导率为 1.35×10-1 S/cm,热分解温度在200℃左右,展现出了在高温环境中的应用潜力,有待于进一步研究。第三章基于PVA和磺化聚醚酮酮(SPEKK),分别通过溶液浇筑法和旋涂法制备了 PVA/SPEKK和(PVA/SPEKK)3复合膜。SPEKK中的磺酸基团和PVA中的羟基之间可以形成氢键,所以制备的复合膜结构稳定。(PVA/SPEKK)3复合膜具有层状结构,其断裂拉伸强度为63.98 MPa。在-30℃下,PVA/SPEKK/85%PA复合膜的质子电导率为9×10-3 S/cm,(PVA/SPEKK)3/85%PA 复合膜的质子电导率为 3.3×10-3 S/cm。更多还原

【Abstract】 Fuel cell is a kind of efficient energy conversion device,which meets people’s practical demand for alternative energy.Among them,proton exchange membrane fuel cells(PEMFCs)have the infinite application potential in the field of new energy vehicles because of the characteristics,such as high energy transformation efficiency,low operating temperature and fast starting speed.As the core component of fuel cells the proton exchange membrane(PEM)is used to transport protons and to block the fuel direct contact between anode and cathode.The Nafion? series membranes manufactured by DuPont are currently the most widely used proton exchange membranes.However,these membranes require water to conduct protons.In some cold areas,the outdoor temperature in winter are usually below 0℃.Nafion? series membranes can not work properly due to water freezing.It is very necessary to develop the low-temperature proton exchange membranes with excellent stability,electrical conductivity and mechanical properties to improve the performance of fuel cells in low-temperature environments.The core of this thesis is to explore proton exchange membranes.In the second chapter of this thesis.PVA,Kevlar and OCNTs were selected to prepare(PVA/Kcvlar/ONNTs)3/PA composite membranes by vacuum assisted flocculation.The composite membrane had an ordered layered structure.The hydrogen bond can be formed between the molecules of the components.The constructed hydrogen bond network provides more channels for proton transport,which effectively improves the proton conductivity of the composite membrane below 0℃.The(PVA/Kevlar/OCNTs)3/85%PA composite membrane exhibited the proton conductivities of 2.17×10-2 S/cm at-30℃ and 1.71×10-1 S/cm at 30℃.Besides,after ten cycles proton conductivity tests of-30℃～30℃.the values reached 5.52× 10-2 S/cm at-30℃and 1.84×10-1 S/cm at 30℃.The proton conductivity retained 1.42×10-2 S/cm after a continuous work of 1900 h at-30℃.In addition,the proton conductivity of(PVA/Kevlar/OCNTs)3/85%PA composite membrane was 1.35×10-1 S/cm at 160℃,and the thermal decomposition temperature was about 200℃,which showed the potential of application in high temperature environment and needed to be further studied.In the third chapter of this thesis,the PVA/SPEKK composite membrane and the(PVA/SPEKK)3 composite membrane were prepared respectively by solution casting and spin casting methods.The composite membranes possess the stable structure because of the formed intermolecular hydrogen bonds between the sulfonic acid group in SPEKK and the hydroxyl group in PVA.The(PVA/SPEKK)3 composite membrane has layered structures,and its tensile strength at break was 63.98 MPa.At-30℃,the proton conductivity of the PVA/SPEKK/85%PA composite membrane was 9×10-3 S/cm,and that of(PVA/SPEKK)3/85%PA composite membrane was 3.3×10-3 S/cm.更多还原