【作者】 杨哲；

【导师】 陈晓春； 夏迎春；

【作者基本信息】 北京化工大学 ， 化学工程（专业学位）， 2021， 硕士

【摘要】 燃料电池作为一种高效、环境友好的新能源发展迅猛,目前已经广泛地应用在人类社会的各个领域。阴离子交换膜(AEM)是一种碱性聚合物电解质,是阴离子交换膜燃料电池(AEMFC)的主要部件。然而AEM的离子传导率不佳及耐碱性能较差一直制约着该类膜的广泛应用。聚苯醚(PPO)以其低廉的成本以及优秀的化学稳定性热稳定性,适合作为阴离子交换膜的主链使用。本文使用聚苯醚为主链,制备了一系列聚苯醚基阴离子交换膜,并对其进行了表征与性能研究。具体开展的研究工作如下:(1)制备了一系列咪唑功能化聚苯醚基阴离子交换膜。对聚2,6-二甲基-1,4-苯醚使用N-溴代丁二酰亚胺进行溴化,然后选用了四种咪唑化合物(N-甲基咪唑、N-正丁基咪唑、1,2-二甲基咪唑以及1-丁基-2-甲基咪唑)对其进行功能化改造,按固定的投料比进行反应,使用溶液浇铸法成膜。将制备得到的一系列咪唑功能化聚苯醚阴离子交换膜进行了物理性能、电化学性能、耐碱性能测试等。测试结果表明,不同膜的离子交换容量、吸水率与溶胀度有一定差异,但是离子传导率基本满足其性能要求。同时,使用1-丁基-2-甲基咪唑作为功能基团的膜耐碱性能最为出色,经过200h的碱处理后,膜的离子传导率仍保持90%左右。(2)为了进一步提高膜的离子传导率,制备了不同溴化程度的溴代聚苯醚,探究功能化程度对所制备膜离子传导率的影响。测试研究发现,随着膜功能化程度的提升,其离子传导性能增加。然而在测试过程中当溴代度升高到45%左右时,膜的吸水溶胀较为严重且变形明显,导致膜的机械性能下降,对膜的使用性产生不利影响。(3)为了进一步提升阴离子交换膜的离子传导率,制备了掺杂离子液体的聚苯醚-离子液体复合膜。选用34%溴代度的溴代聚苯醚作为主链与1-丁基-2-甲基咪唑作为功能化改造材料。制备了两种离子液体将其掺杂到膜中,同时引入纳米二氧化钛对离子液体进行固定。对膜进行测试发现,复合膜离子传导率的最大值达到67 mS/cm,经过碱处理后,部分膜仍具有80%的离子传导率,相较于采用“提升溴代度”提升膜离子传导率的方法,本法在提高膜离子传导率的同时有效减少了膜的过度溶胀行为。更多还原

【Abstract】 Fuel cell is a kind of environment-friendly new energy with high efficiency.At present,it has been widely used in various fields of society.Anion exchange membrane(AEM)is one of the core components of anion exchange membrane fuel cell.However,the poor ion conductivity and poor alkali resistance of anion exchange membrane restrict its application.Poly(2,6-dimethyl-1,4-phenylene oxide)(PPO)is suitable for the polymer skeleton of anion exchange membrane because of its low cost,excellent chemical stability and thermal stability.With PPO as the main chain,a series of PPO based anion exchange membranes are prepared,and their characterization and performance studies are carried out.The specific research is as follows:(1)A series of imidazole functionalized PPO based AEMs are prepared.Nbromosuccinimide was used in brominated PPO.Then four imidazole compounds(N-methylimidazole,N-butylimidazole,1,2-dimethylimidazole and 1-butyl-2-methylimidazole)are selected and their functions are modified.The solution casting method was used according to the fixed feed ratio.In this paper,a series of imidazole functionalized PPO anion exchange membranes are tested for physical properties,electrochemical properties,and alkali resistance.The test results show that the IEC,water uptake and swelling ratio of different membranes are different,but the ionic conductivity basically meets the performance requirements.At the same time,the membrane with 1-butyl-2methylimidazole as functional group has the best alkali resistance.After 200 hours of alkali treatment,the ionic conductivity of the membrane remains about 90%.(2)In order to further improve the ionic conductivity of the membrane,different brominated degrees of brominated PPO are prepared to explore the effect on the ionic conductivity of the membrane.According to the test results,with the improvement of membrane functionality,the ionic conductivity is also increased.However,in the process of testing,when the bromination degree increase to about 45%,the water swelling of the membrane is more serious,and the deformation is obvious,resulting in a decrease of the mechanical properties of the membrane,which is unfavorable to the use of the membrane.(3)In order to further improve the ionic conductivity of the anion exchange membrane,PPO ionic liquid composite membranes doped with ionic liquid are prepared.In this paper,34%brominated PPO is selected as the main chain,and 1-butyl-2-methylimidazole is used as the functional modification material.At the same time,two kinds of ionic liquids are prepared and doped into the membranes,and nano-TiO2 is introduced to immobilize the ionic liquid.According to the membrane test,the maximum ionic conductivity of the composite membrane reaches 67 mS/cm.After alkali treatment,some membranes still have 80%ionic conductivity.Compared with "increasing bromination degree" to improve the ionic conductivity of the membrane,this method can improve the ionic conductivity of the membrane and effectively reduce the swelling of the membrane.更多还原