Corrosion-Induced Microstructural Variability Affects Transport-Kinetics Interaction in PEM Fuel Cell Catalyst Layers

Abstract

The ionomer, which is responsible for proton transport, oxygen accessibility to reaction sites, and binding the carbon support particles, plays a central role in dictating the catalyst layer performance. In this work, we study the effect of ionomer distribution owing to the corrosion induced degradation mode in the catalyst layer based on a combined mesoscale modeling and experimental image-based data. It is observed that the coverage of the ionomer over the platinum-carbon interface is heterogeneous at the pore-scale which in turn can critically affect the electrode-scale performance. Further, an investigation of the response of the pristine as well as degraded microstructures that have been exposed to carbon support corrosion has been demonstrated to highlight the kinetic-transport underpinnings on the catalyst layer performance decay.

Oxygen Permeation Resistances and Routes in Nanoscale Ionomer Thin Film on Platinum Surface

“…16 In the CL fabrication, the carbonsupported Pt particles are mixed with the ionomer solution and selforganize into an extremely complex structure with an approximately 2-3 nm ionomer film that covers the Pt surface. 17,18 Goswami et al 19 found that the ionomer layer's coverage and thickness on the carbonsupported Pt particles are heterogeneous, which affected CL performance. The neutron scattering (NR) and surface X-ray scattering (SXS) technologies 20,21 revealed that the hydrophobic fluorocarbon groups were the main species adsorbed on the Pt (111) surface.…”

Two-Phase Dynamics and Hysteresis in the PEM Fuel Cell Catalyst Layer with the Lattice-Boltzmann Method

“…This process was completed on several different representative volume elements (RVEs) and FIB-SEM geometries to obtain these curves based on work from Goswami. 90 The RVE that best represented the geometry in question while allowing for acceptable run times was the 90x90x(z) cubic voxel geometry, where z represents the number of slices in the FIB-SEM dataset for that geometry. For these simulations, z ranges between 90 and 185.…”

Mechanistic interactions in polymer electrolyte fuel cell catalyst layer degradation

“…The performance model of the CCL solves the multiple physico-chemical transport mechanisms in a volume-averaged sense as enumerated in Goswami et al 50 The assumptions include steady-state operation of the fuel cell under isothermal conditions. In addition, the model is approximated as a single phase such that the byproduct water is existent only in the gaseous phase.…”