Acta Chim. Sinica ›› 2019, Vol. 77 ›› Issue (1): 47-53.DOI: 10.6023/A18080344 Previous Articles     Next Articles

Article

碳纳米管添加剂对质子交换膜燃料电池低铂载量膜电极性能的影响研究

崔丽瑞, 张劲, 孙一焱, 卢善富, 相艳   

  1. 北京航空航天大学空间与环境学院 仿生能源材料与器件北京市重点实验室 北京 100191
  • 收稿日期:2018-08-21 出版日期:2019-01-15 发布日期:2018-11-30
  • 通讯作者: 卢善富, 相艳 E-mail:lusf@buaa.edu.cn;xiangy@buaa.edu.cn
  • 基金资助:

    项目受北京市重点研发计划(No.Z171100000917011)、国家自然科学基金(Nos.21722601,21576007)和中央高校基本科研业务费专项资助.

Effect of Addition of Carbon Nanotubes on the Performance of a Low Pt Loading Membrane-Electrode-Assembly in Proton Exchange Membrane Fuel Cells

Cui Lirui, Zhang Jin, Sun Yiyan, Lu Shanfu, Xiang Yan   

  1. Beijing Key Laboratory of Bio-inspired Energy Materials and Devices, School of Space and Environment, Beihang University, Beijing 100191
  • Received:2018-08-21 Online:2019-01-15 Published:2018-11-30
  • Contact: 10.6023/A18080344 E-mail:lusf@buaa.edu.cn;xiangy@buaa.edu.cn
  • Supported by:

    Project supported by the Key Research and Development Program of Beijing (No. Z171100000917011), the National Natural Science Foundation of China (Nos. 21722601, 21576007) and the Fundamental Research Funds for the Central Universities.

The cell performance and Pt utilization of low-Pt proton exchange membrane fuel cells (PEMFCs) have been significantly improved through incorporating carbon materials into the conventional Pt/C catalytic layer of the membrane electrode assembly (MEA). However, the introduction methods for the carbon materials have not been investigated. In this work, carbon nanotube (CNT) as an additive was added to the low-Pt loading catalytic layer (0.1 mgPt·cm-2) by two methods:a separated CNT layer deposited on the top of the conventional Pt/C layer (CCM-1) and a mixture layer by blending CNT and Pt/C catalyst (CCM-2). The conventional low-Pt loading catalytic layer was employed as control group (CCM-0). The microstructure of the catalytic layers was characterized by scanning electron microscopy, transmission electron microscopy and nitrogen sorption isotherms method. The electrochemical properties of the catalytic layer and membrane electrode were evaluated by cyclic voltammetry (CV), electrochemical impedance (EIS) and linear scanning voltammetry. The results indicated that the cell performance of the conventional low-Pt loading catalyst coated membrane was improved by the introduction of CNTs in both CCM-1 and CCM-2. Compared to the conventional CCM (CCM-0) with a peak power density of 0.522 W·cm-2 at 70℃ and 100% relative humidity (RH) without backpressure, the maximum power densities of CCM-1 and CCM-2 have been improved by 22.4% and 60.0% under the same test conditions, respectively. The increased performance of CCM-1 is believed to result from the enhancement of contact interface between the catalytic layer and the gas diffusion layer in CCM-1 and consequent decrease of the contact resistance. Furthermore, the outstanding power density of CCM-2 is not only owing to the decreased interface contact resistance between the CCM and the gas diffusion layer, but also due to the significant improvement of gas transmission in the catalytic layer, which leads to the decrease of electrochemical reactant resistance and then improvement of the Pt utilization. That has been confirmed by the Pt utilization of 34.4%, 35.6% and 44.7% for CCM-0, CCM-1 and CCM-2. In addition, it also was confirmed by the extremely low power output (2.9 mW·cm-2) of a CCM with only CNT in the catalytic layer when the fuel cell was tested at 70℃ and 100% RH without back pressure. In addition, the optimum loading of CNT in the mixed catalytic layer is 37.5 μg·cm-2 with the peak power density of 0.91 W·cm-2. This work shows that mixing of CNT and Pt/C catalyst into a catalytic layer is an effective method for improving the Pt utilization and reducing the loading of Pt catalyst.

Key words: proton exchange membrane fuel cells (PEMFCs), catalytic layer, carbon nanotube, low-Pt loading, membrane electrode assembly