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This content will become publicly available on December 9, 2018

Title: Microstructural Analysis and Transport Resistances of Low-Platinum-Loaded PEFC Electrodes

In this study, we present microstructural characterization for polymer electrolyte fuel cell (PEFC) cathodes with low platinum loadings (low-PGM). The characterization results are used to quantify the contribution of mass transport resistances to cell voltage losses observed in polarization curve data. Three-dimensional pore morphology and ionomer distribution are resolved using nano-scale X-ray computed tomography (nano-CT). Electrode structural properties are reported along with analysis of the impact of microstructure on the effective charge and reactant transport properties. These characterizations are incorporated with a two-dimensional multi-physics model that accounts for energy, charge, and mass transport along with the effect of liquid water flooding. Defining a total mass transport resistance for the whole polarization curve, contributions of transport mechanisms are identified. Analysis of the experimental polarization curves at different operating pressures and temperatures indicates that the mass transport resistance in the cathode is dominated by the transport processes in the electrode. It is shown that flooding in the electrode is a major contributor to transport losses especially at elevated operating pressures while the pressure-independent resistance at the catalyst surface due to transport through the ionomer film plays a significant role, especially at low temperatures and low catalyst loading. In addition, by performing amore » parametric study for varying catalyst loadings, the importance of electrode roughness (i.e, electrochemically-active surface area/geometric electrode area) in determining the mass transport losses is highlighted.« less
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [3] ;  [1]
  1. Argonne National Lab. (ANL), Argonne, IL (United States)
  2. United Technologies Research Center, East Hartford, CT (United States)
  3. Johnson Matthew, London (United Kingdom)
Publication Date:
Grant/Contract Number:
AC02-06CH11357
Type:
Accepted Manuscript
Journal Name:
Journal of the Electrochemical Society
Additional Journal Information:
Journal Volume: 164; Journal Issue: 14; Journal ID: ISSN 0013-4651
Publisher:
The Electrochemical Society
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE) - Office of Fuel Cell Technologies (FCTO); USDOE Office of Science - Office of Basic Energy Sciences - Energy Frontiers Research Center - Energy Materials Center at Cornell
Country of Publication:
United States
Language:
English
Subject:
25 ENERGY STORAGE; PEFC; PEMFC; Proton-exchange membrane fuel cell; X-ray computed tomography; catalyst layer; catalyst loading; electrode microstructure; low-PGM electrode; mass transport resistance; nano-CT; polymer electrolyte fuel cell
OSTI Identifier:
1427488