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Title: Durability of De-Alloyed Platinum-Nickel Cathode Catalyst in Low Platinum Loading Membrane-Electrode Assemblies Subjected to Accelerated Stress Tests

Here, the durability of de-alloyed platinum-nickel catalysts supported on high-surface area carbon (d-PtNi/C) in optimized electrodes and membrane electrode assemblies (MEAs) under an accelerated stress test (AST) protocol is investigated with the objective of developing a quantitative understanding of the degradation mechanisms and their relationship to the electrode structure, pre-conditioning, and operating conditions. It is found that the cell degradation can be mitigated by controlling the voltage cycle, acid washing the MEA to remove Ni contaminants that enter the electrode and membrane during fabrication, and monitoring the operating conditions. For example, the electrochemical surface area (ECSA) loss is <25% after 30,000 triangle cycles with 0.925 V upper potential limit if the MEA is acid washed and extensive diagnostics are avoided. The parameters that exacerbate the cell degradation also accelerate the rate at which Ni leaches out from the catalyst. A mechanistic model is presented for the degradation in performance of d-PtNi/C electrodes. The model correlates a) the degradation in ORR mass and specific activities with ECSA and Ni losses, b) the decrease in limiting current density ( iL), which is inversely proportional to the O 2 mass transport resistance, with the degradation in catalyst roughness factor, and c) the increasemore » in mass transfer overpotentials with the reduced current density, i/iL .« less
Authors:
ORCiD logo [1] ;  [1] ;  [1] ;  [1] ; ORCiD logo [1] ;  [2] ;  [2] ;  [3] ;  [4] ;  [4] ;  [4]
  1. Argonne National Lab. (ANL), Argonne, IL (United States)
  2. Univ. of Texas at Austin, Austin, TX (United States)
  3. United Technologies Research Center, East Hartford, CT (United States)
  4. Johnson Matthey Technology Centre, Reading (United Kingdom)
Publication Date:
Grant/Contract Number:
AC02-06CH11357
Type:
Published Article
Journal Name:
Journal of the Electrochemical Society
Additional Journal Information:
Journal Volume: 165; Journal Issue: 6; 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)
Country of Publication:
United States
Language:
English
Subject:
25 ENERGY STORAGE; Catalyst durability; Mass transfer in cathode catalysts; Polymer electrolyte fuel cells
OSTI Identifier:
1434558
Alternate Identifier(s):
OSTI ID: 1437277