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

Journal Article · Fri Mar 16 00:00:00 EDT 2018 · Journal of the Electrochemical Society

DOI:https://doi.org/10.1149/2.0341806jes· OSTI ID:1434558

Ahluwalia, R. K. ; Wang, X.; Peng, J-K; Kariuki, N. N.; Myers, D. J. ; Rasouli, S.; Ferreira, P. J.; Yang, Z.; Martinez-Bonastre, A.; Fongalland, D.; Sharman, J.

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 (i_L), which is inversely proportional to the O₂ mass transport resistance, with the degradation in catalyst roughness factor, and c) the increase in mass transfer overpotentials with the reduced current density, i/i_L .

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE)
• Grant/Contract Number: AC02-06CH11357
• OSTI ID: 1434558
• Alternate ID(s): OSTI ID: 1437277
• Journal Information: Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Vol. 165 Journal Issue: 6; ISSN 0013-4651
• Publisher: The Electrochemical Society
• Country of Publication: United States
• Language: English

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