Degradation mechanism study of PTFE/Nafion membrane in MEA utilizing an accelerated degradation technique

作者：Jao Ting Chu; Jung Guo Bin^*; Kuo Shun Chi; Tzeng Wei Jen; Su Ay

来源：International Journal of Hydrogen Energy, 2012, 37(18): 13623-13630.

DOI：10.1016/j.ijhydene.2012.02.035

• Proton exchange membrane fuel cell (PEMFC)
• PTFE/Nafion (PN) composite membrane
• Creep deformation
• Accelerated degradation test (ADT)
• Degradation mechanisms

Nafion membranes are widely used for commercial membrane electrode assemblies (MEAs) in proton exchange fuel cells (PEMFCs). The polytetrafluoroethylene (PTFE)/Nafion (PN) composite membrane has the advantages of being low in cost, high in mechanical strength, and does not swell excessively. This study focuses on the properties of PTFE/Nafion membranes and PTFE/Nafion MEAs by comparing the durability and performance of the PN MEAs to commercial Nafion 211 MEAs. In an accelerated degradation test (ADT), the characterization of PTFE/Nafion and Nafion MEAs were analyzed using in-situ electrochemical methods such as polarization curves, AC impedance, cyclic voltammetry (CV), and linear sweep voltammetry (LSV). The results demonstrate an increase in the internal resistance on the PTFE/Nafion MEA only. The three mechanisms behind this unique result were proposed to be: (a) Separation of the catalyst layer from the membrane due to creep deformation; (b) Separation of the outer Nafion layer film from the core PTFE/Nafion membrane due to creep deformation; (c) Degradation of the Nafion plane (or Nafion dissolution) from the PTFE surface. %26lt;br%26gt;The scanning electron microscope (SEM) images indicate that only the PTFE/Nafion MEA curved after the ADT. Mechanism (a) was therefore the most possible phenomenon for the increase in internal resistance of the PN MEA.

• 出版日期2012-9