Based On Speek Composite Proton Exchange Membrane Preparation And Performance Studies

The proton exchange membrane is the electrolyte of the fuel cell.In the fuel cell,the oxidant is separated from the fuel.It is crucial for the proton exchange membrane fuel cell and directly affects the performance of the proton exchange membrane fuel cell.At present,the most used is perfluorosulfonic acid proton exchange membrane,such as Nafion series membrane,which has high conductivity,high chemical stability and high mechanical properties.However,Nafion membrane has high methanol permeability under high temperature and low humidity conditions,and its high cost limits its wide application.Sulfonate poly(ether ether ketone)has low cost,high conductivity and alcohol resistance,simple preparation,and is considered by many scholars as a new material to replace Nafion membrane.Poly(ether ether ketone)membranes with high sulfonation degree are easy to absorb water and swell,which causes the dimensional stability and mechanical stability of the membrane to decrease.Poly(ether ether ketone)membranes with low sulfonation degree show lower conductivity.In order to solve this problem,the modification of SPEEK membranes has been a hotspot in recent years.Adding hydrophilic substances and establishing continuous proton channels in SPEEK membranes have become the main measures to improve electrical conductivity.In this paper,SPEEK is used as the matrix,and the conductivity of the composite membrane is improved by adding a hydrophilic substance HPW.HPW is a hydrophilic substance and is easily lost in the membrane.Therefore,PVP is used to fix HPW,hoping to obtain excellent performance composite membrane.By adding different proportions of PVP,a series of composite membranes were prepared.The structural morphology,water absorption rate,swelling rate,electrical conductivity,HPW loss rate were also studied.Secondly,polyacrylonitrile fibers were prepared by electrospinning technology,and carbon nanofibers were obtained through carbonization treatment.The structure and morphology of carbon fiber were analyzed,composite membrance containing carbon nanofibers with different diameters and carbon nanofibers modified with sulfonic acid was prepared by pouring method,and the performance of the composite film was tested.The result shows:(1)The water absorption rate of the SPEEK/HPW-20 composite membrane at 20°C is 1.16 times that of the pure SPEEK membrane,and the proton conductivity is0.077S/cm,which is 1.92 times that of the pure SPEEK membrane,but the HPW loss rate at 50 ° C reaches 94 %,Resulting in a decrease in membrane performance.In order to reduce the loss of HPW,doped with different amounts of PVP,a series of SPEEK/HPW/PVP-X composite membranes were prepared.The conductivity of SPEEK/HPW/PVP-6 composite membranes at 20°C was 1.6 times that of pure SPEEK membrane.The conductivity of SPEEK/HPW/PVP-8 composite membrane is 1.3 times that of pure SPEEK membrane.The conductivity of SPEEK/HPW/PVP-10 composite membrane is 1.15 times that of pure membrane,the degree of swelling is 16%,17%,16%.The swelling degree of pure SPEEK membrane(16%)is equivalent,The three membranes have good dimensional stability.After 9 days of immersion at 50 degrees,the loss rate was 10%,7%,and 0% of SPEEK/HPW membrane(94%),respectively.Explain that the right amount of PVP can help stop the loss of HPW.(2)With the increase of CNFa,CNFb and SCNFa content at 20?,the water absorption of the composite membrane is 2 times,1.9 times and 1.5 times of SPEEK membrane.It shows that carbon nanofibers and modified carbon nanofibers have a certain water retention capacity.The corresponding swelling rate also increases.The conductivity of SPEEK/CNFa-4 composite membrane is 1.2 times that of SPEEK membrane,the conductivity of SPEEK/CNFb-3 composite membrane is 1.3 times that of SPEEK,and the conductivity of SPEEK/SCNFa-4 composite membrane is 1.7 times that of SPEEK membrane.With the increase of carbon nanofibers,the larger the diameter,the less conducive to proton conduction.The introduction of sulfonic acid provides more sites for proton transfer and promotes proton conduction.