Towards reliable correlation of microporous layer physical characteristics and PEMFC electrochemical performance

Polymer electrolyte membrane (PEM) fuel cells are promising clean energy alternatives to non - sustainable fossil fuels. During fuel cell operation, external humidification of reactant gases is typically required in order to increase PEM conductivity for improved performance. However, the use of external humidification is costly and increases system complexity. Recently it has been found that by including a cathode microporous layer (MPL) in the membrane electrode assembly (MEA) , performance under dry conditions (no external humidification) can be significantly improved . However, the precise function of the MPL is not well understood and therefore there is little theoretical basis to optimisation of physical properties. One possible reason for this lack of understanding is the absence of a well-established fabrication, characterization and electrochemical testing methodology for MPL research. In particular, current research places little emphasis on the effect of MEA variance on the uncertainty in MPL electrochemical performance results. In this study a methodology is developed for fabricating, characterizing and testing MPLs to accurately correlate physical properties with in-situ electrochemical performance. MPLs of two significantly different thicknesses (approximately 20 and 50 μm in the thickest regions) were fabricated in - house using a doctor blade method and varying the ink composition. The pore structure and thickness of MPLs were characterized by mercury intrusion porosimetry (MIP), scanning electron microscopy (SEM) and X-ray micro computed tomography (μCT).

Grantor dc:publisher.institution

Centre for Catalysis Research

Year dc:date.issued

2014

Author dc:creator

• Crymble, Gregory A

Advisors dc:contributor.advisor

• Conrad, Olaf
• Hussain, Nabeel

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/11427/12831

OAI identifier oai:identifier

oai:open.uct.ac.za:11427/12831