【摘要】 以磺化聚醚砜(SPES)为基体,以不同比例的SiO2溶胶与磷钨酸(PWA)为掺杂物,制备了一种有望用于直接甲醇燃料电池(DMFC)的新型SPES/PWA/SiO2有机-无机复合膜,并经热失重分析(TGA)、差示扫描量热仪(DSC)、扫描电镜(SEM)-X射线能谱分析(EDX)等对膜的结构和性能进行了表征,探讨了复合膜用作质子交换膜的可能性.结果表明:复合膜较纯SPES膜具有更高的热稳定性、玻璃化转变温度和吸水率;虽然在室温和电池操作温度(80℃)下,复合膜的拉伸强度均低于纯SPES膜,但即使当SiO2含量高达20%(w)时,复合膜的拉伸强度仍高于Nafion112膜的;SEM图片显示SiO2和PWA在膜中分布均匀,这将有利于连续质子传输通道的形成.对于SiO2含量为15%(w),PWA含量为6%(w)的复合膜,其室温质子传导率达到了0.034S·cm-1,与Nafion112膜的相当,但其甲醇渗透率明显降低,仅为商用Nafion112膜的七分之一左右,这表明该复合膜在直接甲醇燃料电池中具有良好的应用前景.更多还原

【Abstract】 Novel sulfonated poly(ether sulfone) (SPES)/phosphotungstic acid (PWA)/silica organic-inorganic composite membranes for application in direct methanol fuel cells (DMFCs) were prepared by doping SiO2 sol and PWA into SPES matrix. The structure and performance of the obtained membranes were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX), etc. Compared with the pure SPES membrane, SiO2 and PWA doping led to higher thermal stabilities, a higher glass transition temperature (Tg), and higher water uptake. At 20 ℃ and a fuel cell operating temperature of 80 ℃, the tensile strength of all the composite membranes was lower than that of the SPES membrane. However, even when the content of SiO2 was as high as 20% (w), the composite membrane still possessed a higher strength than a Nafion 112 membrane. The morphology of the composite membranes indicated that SiO2 and PWA were uniformly distributed throughout the SPES matrix, which may facilitate proton transport. The proton conductivity of the composite membrane (SPES-P-S 15%: 15% (w) SiO2 and 6% (w) PWA) reached 0.034 S·cm-1, which was similar to that of the Nafion 112 membrane at room temperature. However, methanol permeation through the SPES-P-S 15% composite membrane decreased dramatically and was only one-seventh that of the Nafion 112 membrane. This excellent selectivity of the SPES/PWA/SiO2 composite membrane points to its potential use as a promising electrolyte for DMFCs.更多还原