Research Of Nanofiber Reinforced Proton Exchange Membrane

Proton exchange membrane fuel cell, because of its high energy conversion efficiency, high power density, low temperature start, and no pollution, etc., is widely used in automotive power engine, portable power supply and so on. Proton exchange membrane (PEM) is one key component in proton exchange membrane fuel cell. The membrane can conduct the proton, seprate the fuel and oxidizer and prevent the cell from short circuit. Improving fuel cell operating temperature can effectively improve the thermal management of water in the fuel cell and prevent the catalyst from poisoning. However, the widely used Nafion proton exchange membrane (such as the Nafion series of film) can not work without water. When the working temperature is above 100℃, the proton conductivity decreases as a result of severe dehydration in the membrane. Meanwhile,the maximum effective operating temperature is limitied due to its lower glass transition temperature.In this paper, SiO2/PVDF composite nanofiber membrane and SiO2 nanofibers were prepared by electrospinning. Then the SiO2/PVDF/Nafion nano fiber and SiO2 nanofibers which as a enhance body was dipped in the perfluoro-sulfonic polymer to fabricate the SiO2/PVDF/Nafion and SiO2/Nafion composite proton exchange membrane, aims to improve the performance of proton exchange membrane water and enhance membrane hot mechanical properties at the same time, then improve the protons conductivity at high temperatures, improve battery performance. High-temperature working And on this basis the composite film thermal stability and thermal mechanical properties, inspected the composite membrane in different temperature protons conduction performance. Get the following results:(1) Composite nanofiber membrane was successfully prepared by electrospinning. The surface of 30%SiO2/PVDFfiber surface is smooth,the single fiber is straight, the diameter of nanofiber is about 500-800nm. SiO2/PVDF nanocomposite fiber membrane was used as reinforcement to fabricate Si02/PVDF/Nafioncomposite proton exchange membrane, nanofibers distribution was uniformly. The TG and TMA tests showed that the glass transition temperature of SiO2/PVDF/Nafion composite proton exchange membrane was improved, and thermal stability was significantly higher than Nafion membrane. Water swelling test showed that the dimensional stability of composite membrane was improved. AC impedance measurement showed that the SiO2/PVDF/Nafion composite membrane conductivity increased when the SiO2 content in the fiber increased, up to 0.23S/cm-1.(2) SiO2/Nafion short fiber reinforced composite proton exchange membrane was fabricated by recasting methode. SiO2 nanofibers diameter was 300-600nm. The TG and TMA tests showed that SiO2 nanofiber could effectively improve the strength, thermal stability and thermal mechanical properties of SiO2/Nafion composite membrane. Water swelling test showed that the dimensional stability of composite membrane was improved. AC impedance measurement showed that the proton conductivity of composite membrane was improved, up to 0.26S/cm-1.