| The alkaline anion exchange membrane fuel cells（AAEMFCs）possess the advantages of low noise,high energy density,high start-up speed and low operating temperature,which are regarded as a new generation of revolutionary energy device.The core component of AAEMFCs is the anion exchange membranes（AEMs）,and they are facing the challenge of low hydroxide conductivity,poor dimensional stability and unsatisfactory alkaline stability.Therefore,current research of AAEMFCs focuses on the design and preparation of novel AEMs with high conductivity and good stability.In this study,a series of composite AEMs are prepared by incorporating rigid porous materials functionalized with poly ionic liquids into quaternized poly（2,6-dimethyl-1,4-phenylene oxide）（PPO）,which exhibit high hydroxide conductivity and excellent dimensional stability and alkaline stability.In order to solve the"trade-off"effect between the hydroxide conductivity and dimensional stability of AEMs,the cationic metal organic framework functionalized with quaternary ammonium salt（QA@（Ui O-66-NH2）+Cl-）was synthesized by anion stripping-vacuum impregnation-in situ polymerization methods.The disappearance of the F peak and the appearance of the Cl peak in the EDS spectrum confirmed the cationic modification of Ui O-66-NH2.The EDS-mapping diagram revealed that the polyionic liquid is evenly distributed in the channel of（Ui O-66-NH2）+Cl-.Then QA@（Ui O-66-NH2）+Cl-/PPO-x composite AEMs were prepared by hybridizing QA@（Ui O-66-NH2）+Cl-with quaternized poly（2,6-dimethyl-1,4-phenylene oxide）.The effects of QA@（Ui O-66-NH2）+Cl-doping amount on the hydroxide conductivity and dimensional stability of membranes were investigated.As the results indicated,the hydroxide conductivity of QA@（Ui O-66-NH2）+Cl-/PPO-5 composite membrane reached up to 123 m S·cm-1 at 80°C and 100%relative humidity（RH）,and the swelling rate of QA@（Ui O-66-NH2）+Cl-/PPO-5 was merely 10.5%,as well as the tensile strength was 24.5MPa.To further improve the alkaline stability of AEMs,hyper-crosslinked microporous polymers（HCPs）with high chemical stability were selected as membrane composites.A benzene-knitting hyper-cross-linked polymer（BHCP）with high specific surface area(612.7m2·g-1)was synthesized by the"knitting"method using external cross-linker,and quaternary ammonium functionalized hyper-cross-linked polymer（QA@BHCP）was synthesized via the“ship in a bottle”method.EDS-mapping diagram indicated that the polyionic liquid was evenly distributed in the channel of BHCP.QA@BHCP/PPO composite anion exchange membranes were prepared by hybridizing QA@BHCP and quaternized PPO.The effects of QA@BHCP doping amount on the hydroxide conductivity and alkaline stability of membranes were investigated.The results showed that the hydroxide conductivity of QA@BHCP/PPO-3 composite membrane at 80°C and 100%RH was 98 m S·cm-1;the introduction of HCPs with high chemical stability significantly improved the alkaline stability of AEMs.QA@BHCP/PPO-3 composite membrane still exhibited 88%conductivity residual rate after soaking in 2 M Na OH solution at 60°C for 5 days. |
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