Study Of PVDF/PSSA/TiO₂ Composite Membrane For Fuel Cell

Great improvements in fuel cell were achieved in the last decades due to its high efficiency and zero ejection. Direct methanol fuel cells (DMFC) were considered as an alternative to the present power sources for their numerous benefits, including high efficiency, high power density, low or zero ejection and easy fuel carriage. Proton exchange membrane (PEM) is one of the key components of proton exchange membrane fuel cell (PEMFC) and its properties will profoundly the performance of PEMFC. Development of new kinds of PEM for DMFC is important for the membrane science. However, the present PEM used in fuel cells have poor resistance to methanol crossover, which results in not only fuel lost but also poor performance. Thus, the development of PEM with better resistance to methanol crossover is the requirement of theory study and practice.Polystyrene sulfonic acid (PSSA) with different sulfonated degrees was prepared by the reaction of PS with acetylsulfuric ester. The optimum sulfonation conditions were determined based on the study of the amount of sulfonating agent, temperature and reaction time. The structure of PSSA was characterized by FTIR.Poly (vinylidene fluoride) which has carbon-florine backbone possesses good thermal and chemical stability and mechanics strength. In this study, the PVDF/PSSA blend membranes were prepared by using PVDF as cage construction and PSSA as ionic conductor. SEM used to investigate the surface morphology of the blend membrane. The thermal stability of the blend membrane is studied by DTA. The IEC value, water sorption ratio, degree of swelling, ionic conductivity and alcohol rejection property of the blend membranes was also studied. The optimum ratio of PSSA in the blend membrane was chosen and the PVDF/PSSA blend membrane with some pores was obtained.