物理化学学报 >> 2010, Vol. 26 >> Issue (06): 1722-1726.doi: 10.3866/PKU.WHXB20100618

材料物理化学 上一篇    

重离子辐照制备电池用微孔膜及其阻抗性质

曲晓华, 刘杰, 王兆翔, 曹殿亮, 房向鹏, 张苓, 段敬来, 姚会军, 陈艳峰, 孙友梅, 侯明东   

  1. 中国科学院近代物理研究所, 兰州 730000; 中国科学院研究生院, 北京 100049; 中国科学院物理研究所, 北京 100190
  • 收稿日期:2010-01-20 修回日期:2010-03-22 发布日期:2010-05-28
  • 通讯作者: 刘杰 E-mail:j.liu@impcas.ac.cn

Preparation of Microporous Membranes by Swift Heavy Ion Irradiation and Impedance Characterization

QU Xiao-Hua, LIU Jie, WANG Zhao-Xiang, CAO Dian-Liang, FANG Xiang-Peng, ZHANG Ling, DUAN Jing-Lai, YAO Hui-Jun, CHEN Yan-Feng, SUN You-Mei, HOU Ming-Dong   

  1. Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, P. R. China; Graduate University of Chinese Academy of Sciences, Beijing 100049, P. R. China; Institute of Physics, Chinese Academy of Sciences, Beijing 100190, P. R. China
  • Received:2010-01-20 Revised:2010-03-22 Published:2010-05-28
  • Contact: LIU Jie E-mail:j.liu@impcas.ac.cn

摘要:

利用离子辐照结合径迹蚀刻方法制备聚丙烯(PP)微孔膜. 用加速器产生的单核能为11.4 MeV·u-1(总能量2245.8 MeV)的197Au离子束辐照PP膜, 剂量为1×108 ions·cm-2. 辐照后PP膜沿离子路径产生损伤区域, 用硫酸与重铬酸钾的混合液进行蚀刻(5-30 min), 制备出孔径为380-1610 nm的聚丙烯微孔膜. 对膜的表面和断面形貌进行表征, 微孔膜的孔径大小及空间分布均匀, 孔道上下贯通, 形状近似为圆柱形. 给出了微孔膜的孔隙率理论公式. 将制备的聚丙烯微孔膜用作锂离子电池隔膜, 用电化学阻抗谱(EIS)测定浸满电解液的微孔膜的离子电导率, 并与商用隔膜进行比较. 分析表明辐照剂量和孔径大小均会影响膜的孔隙率和离子电导率, 选择合适的辐照剂量和蚀刻时间, 可以制备出孔隙率和离子电导率符合应用标准的聚丙烯微孔膜.

关键词: 电化学阻抗谱, 聚丙烯微孔膜, 锂离子电池隔膜, 快重离子辐照, 径迹蚀刻

Abstract:

Polypropylene (PP) microporous membranes were successfully prepared by swift heavy ion irradiation and track-etching. Polypropylene foils were irradiated with 197Au ions of kinetic energy 11.4 MeV·u-1 (total energy of 2245.8 MeV) and fluence 1×108 ions·cm-2 at normal incidence. The damaged regions produced by the gold ions along the trajectories were etched in H2SO4 and K2Cr2O7 solutions leading to the formation of cylindrical pores in the membranes. The pore diameters of the PP microporous membranes increased from 380 to 1610 nm as the etching time increased from 5 to 30 min. The surface and cross-section morphologies of the porous membranes were characterized by scanning electron microscopy (SEM). The micropores in the membranes were found to be cylindrical in shape, homogeneous in distribution, and equal in size. Some mathematical relations of the porosity of the PP microporous membranes were established by analytic derivation. The microporous membranes were used in lithium-ion batteries to measure their properties as separators. The electrical conductivity of the porous membrane immersed in liquid electrolyte was found to be comparable to that of commercial separators by electrochemical impedance spectroscopy (EIS). The results showed that the porosity and electrical conductivity were dependent on the ion fluence and etching time. By adjusting these two factors, microporous membranes with good porosity and electrical conductivity were made that met the requirements for commercial use.

Key words: Electrochemical impedance spectroscopy, Polypropylene microporous membrane, Lithium-ion battery separator, Swift heavy ion irradiation, Track-etching

MSC2000: 

  • O647