Preparation Of MOFs/COFs-based Hybrid Membranes For Proton Conduction

Proton exchange membrane（PEM）is the core component of a proton exchange membrane fuel cell（PEMFC）and is an important part of measuring the performance of a fuel cell.The development of introducing guest molecules into MOFs/COFs materials and combining them with conductive polymers as proton exchange membranes has broadened the thinking.In order to further improve conductivity of MIL-101,CIN and MPA,they were functionalized with ionic liquids and organic phosphoric acids.Then the obtained composite material was doped with PVP/PVDF and CS respectively to prepare a series of composite films.XRD,FT-IR,TGA,SEM and nitrogen absorption-desorption tests were performed on all the materials prepared above,and their proton conduction properties were studied.The specific results are as follows.（1）The ionic liquid（IL）was introduced into MIL-101 to synthesize a composite material（IL/MIL-101s）by the ship-in-bottle method（SIB）.The obtained IL/MIL-101s with high water retention.SIB-3 exhibits high proton conductivity(σ=4.4×10^-2 S cm^-1)at low reality humidity～23%,which is five orders of magnitude higher than MIL-101(1.1×10^-7 S cm^-1).SIB-3 follows the Grottuss mechanism.In addition,IL@MIL-101s was incorporated into the polymer blend as a filler to form a composite film,and the proton conductivity was as high as 4.3×10^-3 S cm^-1 at about 23%RH at 323 K.（2）The NTP/CIN complex is obtained by immobilizing nitrilotrimethylphosphonic acid（NTP）molecules in the pores of a nitrogen-rich covalent imine network（CIN）,and then NTP/CIN is incorporated into CS form hybrid membrane.NTP/CIN@CS has a relatively high proton conductivity of 7.8×10^-3 S cm^-1 at～98%relative humidity at328 K.The proton conductivity of NTP/CIN@CS-4 is 71 times and 17 times compared with CS and CIN@CS.（3）A novel microporous organic polymer material（MTA）synthesized an NTP/MTA composite material by post-soaking method,and then prepared composite membrane of NTP/MPA and CS by solution casting method.The proton conductivity of NTP/MTA@CS-H₂SO₄-2 reaches 4.6×10^-2 S cm^-1 at～98%RH and 323 K,which is 418 times higher than CS membrane.