Tham khảo tài liệu 'materials for the hydrogen economy (2007) episode 11', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 276 Materials for the Hydrogen Economy FIGURE SEM analysis of an MEA sample from a failed stack showing the ruptured membrane as a result of mechanical failures. blister and creep . Fully gasketed MEAs with subgaskets covering the membrane edges were first introduced by Gore and they are now available from all major MEA suppliers. Reinforced membranes have been shown to delay crack initiation and PTFE-based porous films woven fibers and microfibers are widely used for membrane reinforcement because of their improved chemical stability and excellent structural compatibility with fluorinated ionomers. W. L. Gore introduced Gore-Select membranes a class of expanded PTFE-reinforced PFSA membranes as thin as 5 240 These enable a fuel cell to achieve a higher power density with significantly improved durability. Asahi Glass reported a fiber-reinforced PFSA membrane with good mechanical strength and Most recently Ballard reported a composite membrane with a Solupor matrix a highly porous and mechanically robust microporous film that is made of ultra high molecular weight MW This film has a thickness of 20 microns and relatively large pores with an overall porosity of 85 . These properties allow for the fabrication of a composite membrane with high mechanical strength and well-controlled thickness. Performance of this composite membrane is similar to that of traditional membranes Materials for Proton Exchange Membrane Fuel Cells 277 but with improved durability. Johnson Matthey presented a reinforced membrane that gave a sixfold increase in durability for a 30-cell stack operated under dynamic operation DuPont recently introduced Nafion XL a reinforced membrane made from a chemically stabilized ionomer see below . It has achieved a 10fold increase in lifetime under low RH and potential cycling Improvement in PFSA Chemical Stability through End-Group Modification .
