质子型离子液体/功能SiO_2复合高温质子交换膜的制备与表征

Synthesis and Characterization of Protic Ionic Liquid/Functionalized SiO_2 Composite High Temperature Pronton Exchange Membranes

通过正硅酸四乙酯水解制备了粒径约为70nm球形SiO_2纳米粒子,合成了1-甲基-3-[(三乙氧基)丙基]咪唑氯化物(离子液体),并对SiO_2纳米粒子进行表面修饰得到离子液体表面修饰的功能SiO_2(Im-SiO_2)。以苯乙烯、丙烯腈为基体材料、以质子型离子液体为质子导体,通过掺杂Im-SiO_2制备复合高温质子交换膜。通过扫描电子显微镜、热重分析仪和电化学工作站研究了质子交换膜的微观形貌、热稳定性和电导率,并考察了Im-SiO_2的含量对质子交换膜性能的影响。研究发现,复合质子交换膜的最高电导率可达10-2 S·cm-1。Im-SiO_2的掺杂对质子交换膜的热稳定性影响不大,但适量Im-SiO_2的掺杂有助于提高质子交换膜的导电性能以及保离子液体的能力。这些结果表明该类复合质子交换膜是高温质子交换膜燃料电池理想的隔膜材料,具有很好的应用前景。

Monodispersed silica nanoparticles with mean diameter of 70 nm were prepared by hydrolysis of tetraethyl orthosilicate.Ionic liquid,1-methyl-3-[（triethoxysilyl）propyl]imidazolium chloride（TMICl）was synthesized and used to modify the surface of silica nanoparticles.The high temperature proton exchange membranes（PEMs）were synthesized via in situ cross-linking of a mixture containing styrene,acrylonitrile,protic ionic liquids（PILs）,and ionic liuid（TMICl）functionalized silica nanoparticles（Im-SiO2）.The morphology,thermal stability and conductivity of PEMs were characterized by scanning electron microscopy,thermogravimetric analyzer and electrochemical workstation,respectively.The effect of Im-SiO2 content on the properties of the PEMs was systematically studied.The results showed that the Im-SiO2 content has little influence on the thermal stability of the PEMs.However,the addition of proper content of Im-SiO2 could effectively increase the proton conductivity and prevent the release of PIL component from the composite membranes.These results make the PEMs show good potential applications in proton exchange membrane fuel cells.