On-line fluoride and pH measurement in outlet water for monitoring membrane degradation in polymer electrolyte membrane fuel cells
Year: 2025
Type: article
Abstract: The chemical degradation of the polymer electrolyte membrane was monitored using on-line measurements of F − and pH in the outlet water during the operation of the fuel cell. The effectiveness of the technique was evaluated under nominal, non-degrading conditions, a chemical stability accelerated stress test (AST), and conditions to eliminate H 2 O 2 production from O 2 crossover. The on-line measurements showed significant decreases in pH from 6 to 4 when degradation occurred and fluoride release rates of 12.1-13.8 μ g cm −2 h −1 during the first 24 h of the AST. The estimation of the total F mass loss using the ion-selective electrode method showed good agreement with the estimation of loss using imaging of membrane thinning. To further evaluate the on-line measurement technique, the effect of using a total ionic strength adjustment buffer (TISAB) solution was investigated on the anode and cathode outlet water samples, the results showed that F − concentrations may be underestimated at pH < 3.5 when the solution was not used. However, the trends and values were largely comparable even without the solution added, which benefits on-line measurement. The on-line technique was also applied to an AST campaign to investigate the effects of varying membrane characteristics, e.g., thickness, side chain length, use of radical scavengers, and presence of F. The highest F − release was observed for the long side chain Nafion membranes, followed by the shorter side chain 3M membranes. Nafion membranes with radical scavengers showed negligible release during the 200 h AST, while the hydrocarbon membranes also showed negligible release as expected, even when using Nafion ionomer in the catalyst layer.
Source: Chemical Engineering Journal
Authors: Adam Zucconi, Robert Anton, Yu Morimoto, Alexander J.E. Rettie, Iryna V. Zenyuk
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,830
OpenAlex ID: W4416549029