Abstract—Polymer electrolyte fuel cells (PEFCs) have recently attracted considerable attention as a promising clean energy source. In the present study, we develop a theoretical model for the overpotential in PEFCs. Protons with sufficient kinetic energy to overcome the potential barrier can pass through the interfaces. They then converge to a constant current, dissipating their kinetic energy. In particular, inelastic collisions of protons at electrode–electrolyte interfaces are considered to be the dominant cause of overvoltage. This model based on the assumptions above differs from conventional continuum models. The effects of potential barriers at interfaces, proton concentrations, temperature, and mass on the voltage loss are clarified by a parameter study. To verify this model, we prepare two different membrane electrode assemblies (MEAs) that have different interface conditions and measure their current–voltage characteristics. As a result, substantial voltage losses from the MEA with the poorer quality interfaces are observed. Theoretical evaluations of the overvoltage are in good agreement with the experimental results. The present results imply that it is essential to control interface conditions to achieve high proton conduction.
Index Terms—Polymer electrolyte fuel cell (PEFC), overpotential, membrane electrode assembly (MEA), interfaces.
K. Doi and S. Kawano are with the Department of Mechanical Science and Bioengineering, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan (e-mail: doi@me.es.osaka-u.ac.jp, kawano@me.es.osaka-u.ac.jp).
H. Hashizume is with the Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan.
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Cite: Kentaro Doi, Hiroki Hashizume, and Satoyuki Kawano, "A Theoretical Model of Overpotential at Interfaces in Polymer Electrolyte Fuel Cells," International Journal of Chemical Engineering and Applications vol. 6, no. 4, pp. 243-249, 2015.
