Poly(Ether Ether Ketone) Anion Exchange Membrane Functionalized With Cyclic Quaternary Ammonium: Syntheses And Properties Studies

Fuel Cell is a kind of electrochemical device that can directly convert the chemical energy in Fuel and oxidizer into electri energy.It has fuel diversity and environmental affinity as well as high energy conversion rate due to being not limited by carnot cycle.Fuel Cell is regarded as an environment-friendly new energy in the21st century and has attracted extensive attention.There are many types of Fuel Cells,among which Anion Exchange Membrane Fuel Cell deserves researching greatly due to advantages of non-precious metals as catalysts,low fuel permeability and electrode corrosion resistance.Anion Exchange Membrane?AEM?,as the core component of Anion Exchange Membrane Fuel Cell,plays a role in conducting OH^-and sequestering fuel/oxidant in the process of battery operation.However,there are some shortcomings in AEM:?1?low ionic conductivity?2?low alkaline stability?3?easily absorbing CO_2.Therefore,it is extremely urgent to develop a new type of AEM with excellent comprehensive performance.At present,quaternary ammonium group is the most common cationic group in AEM,among which the cyclic quaternary ammonium group is the focus of research.In addition,poly?ether ether ketone?is a special engineering plastic with good mechanical property,dimensional stability,thermal stability and chemical stability,which can be used as the main chain structure of AEM.Therefore,the main purpose of the article is to develop poly?ether ether ketone?AEM functionalized with cyclic quaternary ammonium groups.The relationship between structure and properties was studied,mainly contering on“poly?ether ether ketone?AEM functionalized with different heterocyclic quaternary ammonium groups”and“poly?ether ether ketone?AEM functionalized with N-spiro quaternary ammonium groups”1.Alkaline stability of different heterocyclic model compounds was firstly studied.Poly?ether ether ketone?s functioned with these heterocyclic quaternary ammonium groups?QPEEKs?were then prepared aiming to compare the comprehensive preformances of QPEEKs.It was found that all the QPEEKs had good thermal stability,dimension stability and mechanical properties.Besides,QPEEKs functioned with 1-methyl pyrrolidine?MPY?,1-methyl piperidine?MPRD?and trimethylamine?TMA?exhibited higher OH^-conductivities of 0.0399 S cm^-1,0.0388S cm^-1 and 0.0405 S cm^-1 at 80 ^oC in 100%relative humidity.Furthermore,after 24days'test,QPEEK-MPY and QPEEK-MPRD possessed better alkaline stability after immersing in 1 M MaOH solution at 60 ^oC.They exhibited the conductivity loss of28.5%and 33.4%,respectively,which were lower than QPEEK-TMA?37.7%?.All the parameters indicated that QPEEK-MPY and QPEEK-MPRD had good potential in AEMFCs,especially QPEEK-MPY had the best overall performance.2.In order to futher improve the alkaline stability of AEM,the poly?arylene ether ketone?s functioned with N-spiro quaternary ammonium groups in the side-chain?QPEEK-spiro-pyr and QPEEK-spiro-pip?were prepared when utilizing pyrrolidine and piperidine.It was found that QPEEK-spiro-pyr and QPEEK-spiro-pip exhibited OH^-conductivities of 0.0496 S cm^-1 and 0.0309 S cm^-1 at 80 ^oC in 100%relative humidity,respectively.The anion conductivity of QPEEK-spiro-pyr had been significantly improved when compared with QPEEK-MPY.After introducing N-spiro quaternary ammonium groups,the AEMs could form a good hydrophilic and hydrophobic phase reparation structure.Besides,after 20 days'test,QPEEK-spiro-pyr and QPEEK-spiro-pip possessed better alkaline stability after immersing in 1 M MaOH solution at 60 ^oC.They exhibited the conductivity loss of 19.0%and 25.3%,respectively and alkaline stability was significantly improved.In general,QPEEK-spiro-pyr had the best comprehensive performance.