电场控制全氟磺酸膜中磺酸根定向分布的研究  

Study on the directional distribution of sulfonate groups in Nafion membranes under an applied electric field

作　　者：张军芳 宋微[1] 赵雨桐 林永俐 邵志刚[1] ZHANG Junfang;SONG Wei;ZHAO Yutong;LIN Yongli;SHAO Zhigang(Dalian Institute of Chemical Physics,Chinese Academy of Science,Dalian Liaoning 116023,China;University of Chinese Academy of Science,Beijing 100049,China)

机构地区：[1]中国科学院大连化学物理研究所,辽宁大连116023 [2]中国科学院大学,北京100049

出　　处：《电源技术》2023年第5期591-594,共4页Chinese Journal of Power Sources

基　　金：国家重点研发计划(2018YFB1502503);国家自然科学基金(22179127)。

摘　　要：对受热后发生玻璃化转变的Nafion 211膜施加40 V的电场,进而控制磺酸根基团的定向排列,达到提高Nafion膜离子电导率和燃料电池性能的目的。利用透射电子显微镜(TEM)、原子力显微镜(AFM)、X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)和质子电导率等技术研究了电场处理前后膜的相关特性。TEM和AFM表明:与原始膜相比,电场处理膜中-SO_(3)H基团重新排列聚集形成较大的亲水团簇,均匀分布在氟碳基体中,FT-IR显示电场使Nafion 211膜中-SO_(3)H和-CF_(2)-基团对应的峰强度增加。XRD表明电场提高了膜的结晶度。由于电场使亲水团簇彼此连接形成较宽的通道供离子导通,水平方向上电场处理膜的电导率从166.12 mS/cm增加到190.19 mS/cm,垂直方向上电场处理膜的电导率从13.76 mS/cm增加到22.89 mS/cm,燃料电池性能从874.02 mW/cm^(2)增加到919.41 mW/cm^(2)。该研究表明电场对Nafion膜的结构和性能有明显影响,对外场定向质子交换膜的研究及其对燃料电池性能的提升具有重要意义。An electric field of 40 V was applied to Nafion 211 membrane which was undergoing glass transition after heating in this work,so as to control the directional arrangement of sulfonate group,and achieve the purpose of improving the ionic conductivity of Nafion and the performance of fuel cell.The treated membranes were analyzed by transmission electron microscopy (TEM),atomic force microscopy (AFM),X-ray diffraction (XRD),Fourier transform infrared spectroscopy (FTIR) and proton conductivity tests.Results of TEM and AFM showed that,compared with the original membrane,the-SO_(3)H groups in the electric field treated membranes were rearranged and aggregated to form larger hydrophilic clusters which uniformly distributed in the fluorocarbon main chain.The FT-IR tests showed that the intensities of the peaks corresponding to-SO_(3)H and-CF_(2)-groups were remarkably enhanced with the electric field.The data of XRD indicated that the electric field improved the crystallinity of the membranes.Because the electric field caused the hydrophilic clusters to connect with each other to form wider channels for ion conduction,the conductivities were enhanced from 166.12 to 190.19 mS/cm in the membrane’s in-plane direction and from 13.76 to 22.89 mS/cm in the membrane’s through-plane direction,as well as the fuel cell performance increased from 874.02 to 919.41 mW/cm^(2).This study shows that the electric field has a significant effect on the structure and properties of Nafion membranes,which is of great significance for the study of external field-oriented proton exchange membranes and improvements to fuel cell performance.

关 键 词：质子交换膜燃料电池 NAFION膜 电场 

分 类 号：TM911[电气工程—电力电子与电力传动]