【作者】 李岩；

【导师】 吴洪；

【作者基本信息】 天津大学 ， 化学工艺， 2019， 硕士

【摘要】 质子交换膜（PEM）作为质子交换膜燃料电池（PEMFC）的关键部件,决定着电池的性能。目前以Nafion?膜为代表的商用聚全氟磺酸膜存在低湿度（<50%RH）下质子传导率骤降且成本较高的问题;而以磺化聚醚醚酮（SPEEK）膜为代表的成本较低的碳氢链聚电解质膜,质子传导率与尺寸稳定性间存在制约关系,限制了其实际应用。针对上述问题,本研究通过将质子导体功能化氧化石墨烯（GO）和共价有机框架材料（COF）引入高分子基质中,优化膜内化学和物理微环境,提高膜的质子传导率。将咪唑基离子液体（IMD-Si）接枝到GO纳米片上,得到mGO,进而再将磷钨酸通过与咪唑基团间的静电作用负载于m GO上,得到质子导体功能化GO纳米片（P-m GO）,并再将其引入SPEEK高分子基质中,制备了SPEEK/P-m GO复合膜。GO高长径比二维片层结构和磷钨酸在高温下的高质子传导特性,使复合膜内局部具有连续质子传递通道。在65°C,40%相对湿度下,SPEEK/P-m GO-4膜的质子传导率达到5.0 m S cm^-1,是纯SPEEK膜的31.3倍。相较于GO纳米材料,IISERP-CON1型多孔COF材料具有规整有序的一维通道,可为质子传递提供快速通道。将磷钨酸负载于COF纳米粒子中,得到质子导体功能化COF（P-COF）,并再将其引入SPEEK高分子基质中,制备了SPEEK/P-COF复合膜。在65°C,40%相对湿度下,SPEEK/P-COF-15膜的质子传导率达到6.2 m S cm^-1,是纯SPEEK膜的36.5倍。将两性离子接枝到SNW-1型COF骨架,得到有本征质子传导能力的Z-COF,再将其引入到Nafion基质中,制备了Nafion/Z-COF复合膜。Z-COF纳米粒子的引入提高了复合膜保水能力。在80°C,40%相对湿度下,Nafion/Z-COF-10膜的质子传导率达到10.9 m S cm^-1,是重铸Nafion膜的7.3倍。更多还原

【Abstract】 Proton exchange membranes（PEMs）,as the key component of proton exchange membrane fuel cells（PEMFCs）,determine the efficiency and operation stability of PEMFCs.Under low humidity conditions（<50%RH）,Nafion^?membranes,the most commonly used PEMs,would suffer from a sharp decrease of proton conductivity.What’s more,the prices of Nafion^?membranes are pretty high.For low-cost alternative membranes,such as sulfonated polyether ether ketone（SPEEK）,the restrictive relationship between proton conductivity and dimensional stability,limits its practical application.To solve the problems above,the functionalized graphene oxide（GO）and covalent organic frameworks（COFs）were introduced into the polymer matrix to optimize the chemical and physical environments within the membrane,thus enhancing the proton conductivity under low humidity.Imidazolium-based ionic liquids（IMD-Si）were grafted on GO nanosheet to obtain m GO,and then phosphotungstic acid was loaded on m GO nanosheet through the electrostatic interaction with imidazole groups to obtain P-m GO nanosheet.Then P-m GO was introduced into SPEEK matrix to prepare SPEEK/P-m GO composite membranes.GO has a two-dimensional lamellar and phosphotungstic acid has a good proton conductivity under high temperature.The addition of P-m GO could locally construct continuous two-dimensional proton transport channels within the membranes.At 65°C and 40%relative humidity（RH）,SPEEK/P-m GO-4 had a proton conductivity of 5.0 m S cm^-1,which was 31.3 times higher than the pure SPEEK membrane.Compared with GO nanosheet,imidazolium-based COF has an ordered one-dimensional channel,providing an additional pathway for proton transportation.The proton conducting COF（P-COF）were obtained by loading phosphotungstic acids into COF.And P-COF was blending with SPEEK matrix to prepare SPEEK/P-COF composite membranes.At 65°C and 40%RH,SPEEK/P-COF-15 had a proton conductivity of 6.2 m S cm^-1,which was 36.5 times higher than the pure SPEEK membrane.Zwitterion-functionlized COF（Z-COF）was synthesized by grafting zwitterions on the SNW-1 network and doped into Nafion matrix to prepare Nafion/Z-COF composite membranes.The introduction of Z-COF into Nafion matrix renderred enhanced water retention property.Under 80°C and 40%RH,Nafion/Z-COF-10 had a proton conductivity of 10.9 m S cm^-1,which was 7.3 times higher than recast Nafion membrane.更多还原