【作者】 张林；

【导师】 沈春晖；

【作者基本信息】 武汉理工大学 ， 材料科学与工程， 2020， 硕士

【摘要】 碱性阴离子交换膜燃料电池具有阴极反应动力学快、燃料选择广泛以及可使用非贵金属催化剂等优势,已成为下一代低成本燃料电池的主要替代品。阴离子交换膜（AEMs）作为其核心构件,在选择性透过OH^-的同时隔绝了燃料和氧气的接触。目前AEMs研究进展中主要存在两个难题:（1）机械性能和电化学性能的矛盾;（2）导电基团和聚合物骨架的降解,针对后者,本文以聚苯醚（PPO）为聚合物主链,分别以4-氨基-1-甲基哌啶（AMPD）和哌啶基6-偶氮螺环[5,5]十一烷（ASU）为离子传导单元制备了两种不同的阴离子交换膜,具体内容如下:（1）以聚苯醚（PPO）为基体骨架材料,通过亲核取代和Menshutkin反应,制备了不同哌啶阳离子含量的阴离子交换膜。¹H NMR和FTIR测试显示AMPD接枝成功且实现季铵化。SEM结果显示膜的微观结构致密均匀,无孔洞出现。TG测试显示膜在200℃内稳定存在,热稳定性良好。机械性能测试表明膜的拉伸强度随着AMPD含量的增加而减小。离子电导率随着AMPD含量的增加而先增大后减小,其中PPO-AMP-60膜在80℃下的电导率为31.83 m S·cm^-1,在80℃、2 mol·L^-1 Na OH溶液中浸泡10天后,膜的离子电导率稳定在21.29 m S·cm^-1,表明引入AMPD为功能基团在一定程度上有利于提高膜的耐碱性能。（2）利用连续的亲核取代和脱Boc反应合成出哌啶螺环阳离子的盐酸盐（ASU-HCl）,通过亲核取代将ASU引入到PPO体系中,制备了不同哌啶螺环阳离子含量的阴离子交换膜。¹H NMR测试显示成功制备了ASU-Boc并脱除保护基团得到前驱体ASU-HCl,且ASU是以仲胺连接键接枝到BPPO侧链上。SEM结果显示膜的微观结构为均相结构,无宏观相分离。TG测试显示膜在200℃内具有良好的热稳定性。机械性能测试表明膜的拉伸强度随着ASU含量的增加而减小。IEC值、吸水率和溶胀度均随ASU含量的增多而提高,以ASU为功能基团的膜比同含量的PPO-AMP膜的吸水率增大,而氢键的存在可有效控制膜的溶胀,仍具有良好的尺寸稳定性。离子电导率随着ASU含量的增加而增大,其中PPO-ASU-50膜在80℃下的电导率为32.17 m S·cm^-1,在80℃、2 mol·L^-1 Na OH溶液中浸泡10天后,膜的离子电导率稳定在23.36 m S·cm^-1,表明PPO-ASU膜具有良好的耐碱稳定性。更多还原

【Abstract】 Alkaline anion exchange membrane fuel cells have been considered as a primary succedaneum for next-generation and low-cost fuel cell systems since the early 21st century due to utilizing non-noble metal catalysts,having the faster cathode reaction kinetics,and a wide choice of fuels.As the core components,anion exchange membranes（AEMs）can selectively penetrate anions and isolate fuel from oxygen.There exists two main problems in the research progress of AEMs:（1）the contradiction between mechanical properties and electrochemical properties;（2）the degradation of conductive groups and polymer backbone.Aimed at the latter one,in this paper two kinds of anion exchange membranes were prepared from polyphenylene oxide（PPO）and piperidine,as follows:（1）The anion exchange membranes with different contents of piperidine cation were prepared by nucleophilic substitution and Menshutkin reaction.¹H NMR and FTIR results showed that AMPD was grafted onto PPO and quaternized successfully.SEM results displayed that the microstructure of the membranes was compact and uniform,and there were no voids.TG tests exhibited that the membranes could stably exist within 200℃,showing good thermal stability.The mechanical properties tests demonstrated that the mechanical strength of the film declined by the addition of AMPD.The ionic conductivity increased firstly and then decreased with the increase of AMPD content,and the conductivity of PPO-AMP-60 membrane could reach31.83 m S·cm^-1 at 80℃.The results of alkaline resistance showed that the ionic conductivity of PPO-AMP-60 membrane was stable at 21.29 m S·cm^-1 after immersed in 2 mol·L^-1 Na OH solution at 80℃for 10 days,indicating that the introduction of AMPD as functional groups could improve the alkaline resistance of the membranes to some extent.（2）ASU-HCl was firstly synthesized by continuous nucleophilic substitution and deprotection reaction,and then the anion exchange membranes with different contents of piperidine spiro cation were prepared by nucleophilic substitution between ASU and PPO.¹H NMR results showed that ASU-Boc was firstly prepared and then the precursor ASU-HCl was obtained by removal of the protective groups successfully,and ASU was grafted to the BPPO side chain via secondary amine bond.SEM results displayed that the microstructure of the membranes was homogeneous and uniform,and there did not exist macro-phase separation.TG test results showed that the film has good thermal stability at 200℃.The mechanical properties test showed that the tensile strength of the film decreased with the increase of ASU content.IEC,water absorption and swelling ratio increased with the increase of ASU content.Besides,the water absorption of the membranes functionalized by ASU is higher than that of the PPO-AMP membranes at the same content.The existence of hydrogen bond can effectively control the swelling of the membrane,ensuring good dimensional stability.The ionic conductivity test showed that the ionic conductivity of PPO-ASU membrane increased with the increase of ASU components,and the ionic conductivity of PPO-ASU-50membrane was up to 32.17 m S·cm^-1 at 80℃.The results of alkaline resistance showed that the conductivity of PPO-ASU-50 membrane was stable at 23.36 m S·cm^-1 after being immersed in 2 mol·L^-1 Na OH solution at 80℃for 10 days,indicating that the PPO-ASU membranes have good alkaline resistance.更多还原