Physical Modeling of the Proton Density in Nanopores of PEM Fuel Cell Catalyst Layers

Resource type
Date created
2017-08-10
Authors/Contributors
Abstract
In polymer electrolyte fuel cells, a foremost goal is to design catalyst layers with high performance at markedly reduced platinum loading. As a contribution towards this objective, we explore a simplified pore geometry to capture the impact of ionomer structure and metal charging properties on the proton density distribution and conductivity in relevant nanopores. The basic model is a cylindrical tubular pore confined by an ionomer shell and a solid platinum-coated core. The gap region between metal and ionomer is filled with water. We study how the surface charge density at the ionomer and the metal charging relation as well as geometric pore parameters affect the electrochemical performance. The density of charged side chains at the ionomer shell exerts a pronounced impact on the surface charge density at the Pt surface and thereby on the activity of the pore for the oxygen reduction reaction. The key parameter controlling the interplay of surface and bulk charging phenomena is the overlap of the Debye lengths of ionomer and metal surfaces in relation to the width of the gap. It allows distinguishing regions with weak and strong correlation between surface charge densities at ionomer shell and Pt core.
Document
Identifier
DOI: 10.1016/j.electacta.2017.05.052
Published as
Muzaffar, T.; Kadyk, T.; Eikerling, M. Physical Modeling of the Proton Density in Nanopores of PEM Fuel Cell Catalyst Layers. Electrochimica Acta 245 (2017) 1048–1058. https://doi.org/10.1016/j.electacta.2017.05.052
Publication title
Electrochimica Acta
Document title
Physical Modeling of the Proton Density in Nanopores of PEM Fuel Cell Catalyst Layers
Date
2017
Volume
245
First page
1048
Last page
1058
Publisher DOI
10.1016/j.electacta.2017.05.052
Copyright statement
Copyright is held by the author(s).
Scholarly level
Peer reviewed?
Yes
Language
Member of collection
Attachment Size
Muzaffar-June1-2019.pdf 1.84 MB