摘要
Fluorine-free proton exchange membranes(PEMs)capable of healing from physical damage are important for PEM fuel cells(PEMFCs)with extended service life and enhanced reliability.Herein,highly elastic fluorine-free PEMs with excellent self-healing ability and high proton conductivity are fabricated through complexation of phytic acid(PA)with sulfonated polyvinyl alcohol(SPVA),followed by subsequent grafting of SPVA with positively charged 4-(1H-imidazol-1-yl)benzenecarbaldehyde(IBZ).Compared with recast Nafion membranes,the as-prepared SPVA-IBZ/PA membranes exhibit an enhanced mechanical strength and elasticity and can spontaneously recover from a^50%strain to their initial states within^30 s at room temperature.Meanwhile,the SPVA-IBZ/PA membranes have a proton conductivity of^0.095 S cm-1at^70°C,which is higher than that of recast Nafion membranes.The hydrogen-powered PEMFCs using the SPVA-IBZ/PA membranes,which show an open circuit voltage of^0.98 V and maximum power density of^609 mW cm-2,exhibit a satisfactory cell performance.Importantly,the SPVA-IBZ/PA membranes can spontaneously heal mechanical damage of several tens of micrometers in size and restore their original proton conductivity and cell performance under the working conditions of PEMFCs.
具有良好自修复能力的无氟质子交换膜,对延长氢氧燃料电池的使用寿命以及提高其可靠性具有重要意义.本文通过将植酸(PA)与磺化聚乙烯醇(SPVA)复合并在SPVA链上接枝带正电的4-(咪唑-1-基)苯甲醛(IBZ)的方法制备了具有良好自修复性能及高质子传导率的高弹性无氟质子交换膜(SPVA-IBZ/PA).与重铸Nafion膜相比,SPVA-IBZ/PA膜具有较高的机械强度和良好的弹性.室温下,SPVA-IBZ/PA膜可在30 s内从~50%的拉伸应变下自动恢复到初始状态.同时,SPVA-IBZ/PA膜在~70°C时的质子电导率为~0.095 S cm-1,高于重铸Nafion膜.装配SPVA-IBZ/PA膜的氢氧燃料电池具有良好的电池性能,其开路电压为~0.98 V,最大功率密度为~609 mW cm-2.重要的是,SPVA-IBZ/PA膜可以在氢氧燃料电池的工作条件下修复微米级大小的机械损伤,恢复其原有的质子电导率和电池性能.
基金
supported by the National Natural Science Foundation of China(21774049 and 21905105)。
