Preparation And Study Of Catalyst Layer Of Fuel Cell Prepared By Electrospinning Method

The proton exchange membrane fuel cell(PEMFC)is more and more widely concerned by researchers,and is regarded as a clean power generation device that can replace the internal combustion engine in the automobile of the future era.The reason is because of its unique advantages,such as no pollution emissions and high power conversion efficiency.Proton exchange membrane(PEM)is one of the most critical components of this type of fuel cell.It is a kind of membrane that can prevent the gas on both sides of yin and yang from contacting.At the same time,it is responsible for the transfer of protons inside the fuel cell,where protons are both products and substances involved in the reaction,so the proton exchange membrane can affect the overall performance of the fuel cell.The traditional commercialization is widely used in perfluorosulfonic acid proton exchange membrane,but the high cost and insufficient performance limitations directly affect PEMFC's continued commercial development and in-depth research.The preparation of proton exchange membranes with excellent performance and low cost has become an important research direction for researchers.Polyether ether ketone(PEEK)is a special material with excellent performance,and its sulfonation product-sulfonated poly Ether ether ketone(SPEEK)is a material that is very likely to replace perfluorosulfonic acid resin.It was chosen because it has both high proton conductivity and good physical and chemical properties.Electrospinning technology to prepare nano-structured fibers for further expansion and application has always been an important basis for scientific research in our laboratory.In recent years,the combination of nanofiber materials and structures and the field of fuel cells has been increasingly used to prepare better performance proton exchange membranes or other components,and has become a research hotspot.In this paper,based on the electrospinning technology,two new nanofiber structure composite proton exchange membranes were prepared,and a series of comparative tests on their characterization and analysis were performed on them and commercial membranes to verify their application in fuel cells.potential.The details are as follows:1.By conducting sulfonation reaction with PEEK particles and concentrated sulfuric acid,the results of infrared spectroscopy and nuclear magnetic resonance spectroscopy showed that the SPEEK with a sulfonation degree of 73.49%was obtained in this experiment.The higher the sulfonation degree is,the higher the sulfonation degree is.The more sulfonic acid groups that are replaced,the more channels that can be combined with water for proton transfer flow,which can improve the performance of the proton exchange membrane.2.In order to prevent the water absorption and swelling of the SPEEK under high humidity conditions,polyacrylonitrile(PAN),which also has good stability,was introduced.It was prepared by electrospinning and blended to obtain a thickness of about 13 ?m,and the PAN content was SPEEK/PAN composite proton exchange membranes of 4 wt%,5 wt%and 6 wt%.Observation of the SEM image shows that the nanofiber structure exists in the composite proton exchange membrane prepared by the experiment.When the PAN content is higher than 5 wt%,it has a smaller water absorption swelling rate and better mechanical strength than commercial films.Proton conductivity will increase with increasing temperature.Compared with commercial proton exchange membranes,S/P-5 composite proton exchange membranes with a PAN content of 5 wt%at 60? clearly outperform commercial proton exchange membranes.The performance is up to 2.09×10-1 S·cm-1.3.In the 2×2cm2 single cell test,the polarization curve reflects that the performance of the S/P-5 composite proton exchange membrane and commercial proton exchange membrane will increase due to the increase in humidity under the same temperature and different humidity environment.Under the same test conditions,the performance of S/P-5 composite proton exchange membrane is better.The electrochemical impedance spectroscopy also proved that the S/P-5 composite proton exchange membrane has a smaller internal resistance when the fuel cell is operating.The hydrogen leakage current curve reflects that the S/P-5 composite proton exchange membrane has no large area of hydrogen leakage,indicating that the preparation process and parameters of the SPEEK/PAN composite proton exchange membrane are successful.4.Experiments have shown that when the mixing ratio of polytetrafluoroethylene(PTFE)and spinning carrier polyvinyl alcohol(PVA)is 6:1,the spinning effect is the best.The sintering parameters were:pre-oxidized at 220? and then kept at 380? for 40 min to remove impurities to obtain a pure PTFE nanofiber membrane.The Nafion fiber membrane is prepared by electrospinning,and then the Nafion/PTFE composite proton exchange membrane is obtained through a hot pressing process.The composite proton exchange membrane began to decompose weightlessly and showed good thermal stability above 300?.The proton conductivity measured at 60? is 1.18×10'1 S·cm-1,which is lower than 1.91×10-1 S·cm-1 of commercial proton exchange membranes,but it is also within the usable range.The swell rate of water absorption is significantly improved by the addition of PTFE.