MEA degradation in PEM Fuel Cell : a joint SEM and TEM study

• Author(s): Silva, R. A. ; Hashimoto, T. ; Thompson, G. E. ; Rangel, C. M.
• Date: 2011
• Persistent ID: http://hdl.handle.net/10400.9/1466
• Origin: Repositório do LNEG
• Subject(s): PEM fuel Cell; MEA degradation; SEM; TEM
• Document Type: Conference Object
• Language: English

Description

One of the important factors determining the lifetime of polymer electrolyte membrane fuel cells (PEMFCs) is membrane electrode assembly (MEA) degradation and failure. The lack of effective mitigation methods is largely due to the currently very limited understanding of the underlying mechanisms for mechanical and chemical degradations of fuel cell MEAs. This work reports on the effect of 1500 h operation of an eight-cell stack Portuguese prototype low power fuel cell. A performance decrease of 34%, in terms of maximum power, was found at the end of testing period. A post-mortem analysis by SEM and TEM was done for most cells of the fuel cell. Loss of the PTFE ionomer in the anode and cathode catalytic layers; morphological changes in the catalyst surfaces such as loss of porosity and platinum aggregation, deformation on the MEA components (anode, cathode and membrane) were identified. Others, like delamination and cracking were also detected. Catalyst migration and agglomeration on the interface of the electrodes was observed at cells 2, 4, 6 and 7. A platinum band was also detected on the membrane at 2 μm apart from the anode of cell 4. In some cases, dissolution occurred with re-deposition of the platinum particles with facet