Preparation Of Fuel Cell Composite Proton Exchange Membrane And Optimization Of Proton Transfer Process

Proton exchange membrane(PEM),as a core component of proton exchange membrane fuel cells(PEMFC),has an important impact on the performance of PEMFC.Therefore,the design and manufacture of low-cost,high-performance PEMs are critical to the commercial application of PEMFCs.Sulfonated poly(aryl ether sulfone)(SPES)and poly(arylene thioether sulfone)(SPTES)sulfonated polyaryl ether proton exchange membranes were prepared.And three different functional nanofillers were prepared:imino-containing phosphorylated silica nanoparticles(Si-im P),polyvinylimidazole/allotite nanotube core-shell nanotubes(PVI@HNTs),and polyethylene.Imidazole nanotubes(PVINTs).The composite proton exchange membrane was prepared by complexing functional nanofillers with polymer matrix,and the proton exchange process in proton exchange membrane was optimized based on optimization of proton carrier,construction of proton transport channel and bionic optimization of proton transfer process.The main research contents as follows:1.Two kinds of sulfonated polymers,SPES and SPTES were prepared,and two transparent and tough PEMs were prepared by casting method.The study found that both PEMs showed good mechanical properties,moderate water absorption and swelling,good thermal stability and proton conductivity.The proton conductivity of SPES-50 and SPTES-50 were 0.136 S cm^-1 and 0.142 S cm^-1 under complete hydration conditions at 80°C.2.Si-im P was used as a functional proton carrier to optimize the intramembrane proton transfer process.The addition of Si-im P enhanced the performance of the composite membrane.The imino group on the surface of Si-im P could be linked with the sulfonic acid ion cluster of SPTES,and the acidic group and the basic group act synergistically to form a more continuous proton transfer channel and a denser proton hopping network in the composite membrane.The proton conductivity of the composite membrane was 25%more than the SPTES membrane.3.The intramembrane proton transport channel was constructed using PVI@HNTs as a functional nanofiller.The addition of PVI@HNTs to SPES enhanced the thermal stability,mechanical stability and proton conductivity of the membranes.The imidazolyl group of the PVI@HNTs formed acid-base pairs with the sulfonic acid group in the polymer matrix,which constructed proton hopping pathways and low energy barrier nanochannels for proton transfer.The synergistic enhancement of the“Vehicular”mechanism and the“Grotthuss”mechanism conferred high proton conductivity of the SPES/PVI@HNTs-X composite membranes.Compared with the SPES control membrane,the proton conductivity of the SPES/PVI@HNTs-7.5 membrane at 80°C and fully hydrated conditions was 0.198 S cm^-1,which was 46%higher than that of SPES.4.Inspired by the bioproton transfer mechanism,the intramembrane proton transport channel was constructed by PVINTs.The addition of PVINTs to SPES enhanced the thermal stability,mechanical stability and proton conductivity of the membranes.Hydrophilic internal cavity of PVINTs absorbed water through capil-lary action and formed a long-range continuous water transfer pathway,and promoted proton transfer via the“Vehicular”mechanism.In addition,the sulfonic acid-imidazole pair was generated at the interface between the outer surface of the PVINTs and the SPES,which generated a one-dimensional continuous proton transfer pathway and promoted proton transfer through the“Grotthuss”mechanism.The proton conductivity of SPES/PVINTs-7.5 composite membrane reached0.212 S cm^-1 under complete hydration conditions at 80°C,which was 56%higher than that of SPES membrane.