Preparation And Properties Of Semi-interpenetrating Network Composite Membranes Based On Perfluoresulfonic Acid Resin (PFSA)

As the core component of PEMFC,proton exchange membrane(PEM)directly determines its life.At present,perfluoresulfonic acid resin(PFSA)represented by Nafion is facing the following challenges: 1)The trade-off between proton conductivity and mechanical properties;2)Rapid permeability of fuel under low thickness.Therefore,developing high-performance membrane materials is of great significance for the development of proton exchange membrane fuel cells.Therefore,this paper prepares PFSA composite membrane via constructing the semiinterpenetrating polymer network(SIPN).The purpose is to obtain membrane materials with good proton conductivity,gas permeability resistance and stability.The specific research contents are as follows:Firstly,SIPN was constructed by in-situ synthesis using perfluoresulfonic acid resin(PFSA)and p-divinylbenzene(DVB)as raw materials,and a series of ultra-thin PFSA/PDVB semi-interpenetrating network composite membranes were prepared by changing the amount of PFSA and PDVB.Among them,The SIPN-3 showed excellent dimensional stability with a swelling rate of 10.12%.In addition,the hydrogen crossover current density of SIPN-3 was only 1.34 m A/cm2,lower than that of recast PFSA(1.50 m A/cm2)and NC700(2.75 m A/cm2),showing excellent permeability resistance due to the construction of dense cross-linking network.Secondly,to address the problem of low proton conductivity of PFSA/PDVB composite membrane,functionalized inorganic polymetallic anion cluster(POM)was introduced into PFSA in this chapter.The polyimine-POM network was prepared through crosslinking based on dynamic covalent assembly,which achieved hybridization with PFSA to obtain a series of organic-inorganic hybrid semi-interpenetrating network composite membranes.With the abundant oxygen-containing structure on the surface of polyimine-POM,continuous hydrogen bond network can be formed with sulfonic acid group,and efficient ion transport channel can be constructed with the existence of polyanion proton exchange group,thus improving the proton conductivity of the composite membrane.The proton conductivity of hybrid SIPN-10% at 80 oC and 100% RH is 0.259 S/cm,which was 2.8 times that of recast PFSA(0.093 S/cm).Lastly,considering the excellent comprehensive properties of organic-inorganic hybrid membrane materials,the structure of inorganic component,polyimine-POM,was further optimized,and the ordered TBA-polyimine-POM(OT polyimine-POM)and H-polyiminePOM(OH polyimine-POM)were prepared by replacing counter cations and controlling the molar concentration of acetic acid and water in the self-assembly system.The effects of different counter cations and synthetic conditions on ion channel construction were further investigated.