物理化学学报 >> 2009, Vol. 25 >> Issue (11): 2205-2210.doi: 10.3866/PKU.WHXB20091119

研究论文 上一篇    下一篇

粘结剂聚四氟乙烯乳液经过乙醇预处理后对气体扩散电极性能的影响

李芬, 徐献芝, 宋辉, 熊晋, 吴飞   

  1. 中国科学技术大学近代力学系, 合肥 230027
  • 收稿日期:2009-06-10 修回日期:2009-08-27 发布日期:2009-10-28
  • 通讯作者: 李芬 E-mail:fenli@mail.ustc.edu.cn

Impact of Polytetrafluoroethylene Emulsion Binder Pretreatment with Ethanol on the Performance of Gas Diffusion Electrodes

LI Fen, XU Xian-Zhi, SONG Hui, XIONG Jin, WU Fei   

  1. Department of Modern Mechanics, University of Science and Technology of China, Hefei 230027, P. R. China
  • Received:2009-06-10 Revised:2009-08-27 Published:2009-10-28
  • Contact: LI Fen E-mail:fenli@mail.ustc.edu.cn

摘要:

在气体扩散电极的制作工艺中, 加入乙醇对粘结剂聚四氟乙烯(PTFE)进行预处理. 通过全自动微孔物理化学吸附仪对气体扩散电极进行BET比表面积、Langmuir比表面积、孔分布等进行测试, 并用扫描电子显微镜(SEM)检测观察电极表观形貌. 以锌电极作为负极组装成锌空气电池, 检测在不同的电流密度下气体扩散电极相对锌电极的电位变化, 研究PTFE乳液经过乙醇预处理后对电极性能的影响. 结果显示, PTFE乳液经过乙醇处理后, 先膨胀后收缩, 能够增加催化层和气体扩散层的孔隙结构和比表面积,从而使得电极有效电化学反应场所相应增多, 减低电极在大电流密度条件下放电时的极化过电位.

关键词: 气体扩散电极, 乙醇, 聚四氟乙烯乳液, 气体扩散层, 催化活化层, 孔隙结构, 比表面积

Abstract:

Polytetrafluoroethylene (PTFE) emulsion used as a binder for gas diffusion electrodes was pretreated with ethanol before use in electrodes. The surface topography of the gas diffusion electrodes was characterized by scanning electron microscopy (SEM). The BET and Langmuir special surface areas and pore distribution of the gas diffusion electrode were measured using a surface area detector. A zinc-air battery was then assembled and included this pretreated gas diffusion electrode. Under different current densities, the potential changes of the gas diffusion electrodes vs a zinc anode was measured. The impact of the PTFE emulsion alcoholic pretreatment on the performance of the gas diffusion electrodes was studied. The experimental results show that the porous structure of the catalytic activity layers and the gas diffusion layers increase with pretreatment. The reaction zones also increase with an increase in the catalytic activity of the layer's porous structure. Transport of the reactant gas is easier as the porous structure of the gas diffusion layers increase. The polarization potential of the gas diffusion electrode working under a large current density thus decreased.

Key words: Gas diffusion electrode, Ethanol, Polytetrafluoroethylene emulsion, Gas diffusion layer, Catalytic activity layer, Porous structure, Special surface area

MSC2000: 

  • O646