Abstract
The nanostructured thin film (NSTF) catalyst layers which have demonstrated high power densities, mass activities, and exceptional metal and support stability can have limited operational robustness due to their thin thickness and the hydrophilicity of the metal-coated nano whiskers. The dispersed nanostructured thin film (dNSTF) catalyst layers have been developed by dispersing the NSTF Pt whiskers with ionomer and carbon support to increase the thickness and hydrophobicity. Continuum and network models (NM) are coupled through boundary conditions to study the polymer electrolyte fuel cell with a dNSTF cathode catalyst layer. The coupled model combines the computational efficiency of the continuum model with the pore-scale information in the dNSTF cathode catalyst layer of the NM. It captures the special morphology of the partially ionomer/water covered cylindrical whiskers, as well as water percolation through the pore structures and their impact on the cell performance. We observe optimal ionomer coverage on whiskers to be 0.5, ionomer to carbon ratio to be 0.9 and higher whisker to carbon ratios to be desired.
Original language | English |
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Pages (from-to) | 17749-17761 |
Number of pages | 13 |
Journal | International Journal of Hydrogen Energy |
Volume | 47 |
Issue number | 40 |
DOIs | |
State | Published - May 8 2022 |
Funding
This material is based upon work supported by the Department of Energy , Office of Energy Efficiency and Renewable Energy (EERE) , under Award Number DE-EE0007650 . Scanning transmission electron microscopy was conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility. The ORR kinetic model provides the source/sink terms connection between the internal nodes of the different realizations shaping the dNSTF cathode catalyst layer. The ORR kinetic model is implemented on the catalyst/whisker network and dictates how much oxygen will be consumed from nodes of the pore network realization (sink term), how many protons will be consumed from the nodes of the ionomer network (sink term), how much water will be injected onto the nodes of the ionomer network (source term), and how much heat will be injected onto the nodes of the support network (source term).This material is based upon work supported by the Department of Energy, Office of Energy Efficiency and Renewable Energy (EERE), under Award Number DE-EE0007650. Scanning transmission electron microscopy was conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility.
Keywords
- Catalyst layers
- Continuum model
- Dispersed nanostructured thin films
- Ionomer coverage
- Network model
- Polymer electrolyte fuel cells