Optimization of the Microporous Layer for a Polybenzimidazole-based High Temperature PEMFC. Effect of carbon content

Justo Lobato (1) , Pablo Cañizares (2) , Manuel A Rodrigo (2) , Diego Ubeda (2) , Francisco J Pinar (2) , Jose J Linares (2)

1 Chemical Engineering Department
2 Chemical Engineering

This work aims at studying the role of the microporous layer (MPL) in electrodes prepared for High Temperature PBI-based PEMFC. The two main components of this layer are carbon black and a polymeric binder (Teflon). This work addresses the effect of the MPL carbon amount on the performance of a High Temperature PEMFC. Thus, gas diffusion layers (GDL) containing MPL with different carbon contents (from 0.5 to 4 mg cm-2) were prepared. Firstly, they were physically characterized by Hg-Porosimetry measuring pore size distribution, porosity, tortuosity and mean pore size. Permeability measurements were also performed. The higher the carbon content was the lower both porosity and permeability were. Afterwards, electrodes were prepared with these GDLs and were electrochemically characterized. Electrochemical surface area (ESA) was determined and fuel cell performance was evaluated under different fuel and comburent stoichiometries, supporting these results with impedance spectra. This made possible to see the benefits of the MPL inclusion in the electrode structure, with a significant increase in the fuel cell performance and ESA. Once the goodness of the MPL was confirmed, result analysis led to an optimum MPL composition of 2 mg cm-2 of carbon for both electrodes, anode and cathode.

Mots clés: Physical Sciences

Justo Lobato, Pablo Cañizares, Manuel A Rodrigo, Diego Ubeda, Francisco J Pinar, et al.. Optimization of the Microporous Layer for a Polybenzimidazole-based High Temperature PEMFC. Effect of carbon content. Fuel Cells, 2010, 10 (5), pp.770. ⟨10.1002/fuce.200900175⟩. ⟨hal-00578450⟩