Open circuit voltage durability study and model of catalyst coated membranes at different humidification levels

Kundu, Sumit; Fowler, Michael; Simon, Leonardo C.; Abouatallah, Rami; Beydokhti, Natasha

doi:10.1016/j.jpowsour.2010.05.027

Cited by 16 publications

(7 citation statements)

References 34 publications

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“…Experiments were conducted on 2 different types of commercial CCMs fabricated using the decal transfer technique that have the same active area of 48 cm 2 and catalyst loading of 0.2 mg/cm 2 at the anode and 0.5 mg/cm 2 at the cathode (Gore PRIME® CCMs). The first type made with perfluorosulfonic acid (PFSA) membranes reinforced with PTFE fibers were stored for 2 years in the laboratory under ambient conditions prior to fuel cell operation in this study . These samples will be referred to as reinforced CCMs for our purposes here.…”

Section: Methodsmentioning

confidence: 99%

Investigation of catalyst layer defects in catalyst-coated membrane for PEMFC application: Non-destructive method

et al. 2018

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Summary The commercialization of polymer electrolyte membrane fuel cells has been hindered by durability problems caused by defects in the manufacturing process. We demonstrate for the first time a non‐destructive, non‐contact method that uses optical microscopy and image analysis to identify defects that may lead to failure in catalyst‐coated membranes (CCMs) of polymer electrolyte membrane fuel cells. This method is applied to 2 commercial CCMs produced by the decal transfer technique. Defects in the catalyst layer (CL) at the beginning‐of‐life (BOL) are characterized in terms of their initial size and shape, and their propagation is tracked as the CCMs are aged in a non‐reactive environment. The defected area in one of the commercial CCMs increases from approximately 2.4% of the total CL area at BOL to 10.5% by end‐of‐life (EOL). BOL defects in the CL are found to propagate faster in the CCMs stored for 2 years under atmospheric conditions compared with freshly manufactured CCMs with narrow CL defects. Image analysis of another commercial CCM shows the presence of pores with diameters between 5 and 25 μm that comprise 52% of the total pore area in the CL. Other defects such as scratches and missing/empty catalyst areas are identified and characterized, providing a framework for quality control applications. Finally, the effect of defects on fuel cell performance is characterized by measurement of the open‐circuit voltage (OCV). These experiments show that CCMs with a large number of cracks in the CL exhibit a voltage loss of 2.55 mV/hr, whereas CCMs with thin/missing/empty CL defects show a loss of 1.12 mV/hr.

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Section: Methodsmentioning

confidence: 99%

Investigation of catalyst layer defects in catalyst-coated membrane for PEMFC application: Non-destructive method

et al. 2018

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“…Kundu et al [201] detected significant loss of fluoride, by around 45%, when RH was reduced from 100% to 20% (e.g. from ~29 to 52 μmol cm -2 ).…”

Section: Mea and Gdl Structurementioning

confidence: 99%

“…Previous studies associated the dissolution of ionomer from MEAs to a number of factors such as hydrogen crossover [199], Nafion loading [198], and cell operation under OCV [44,200] and extreme relative humidity conditions [30,201]. However, none of these studies associated the segregation of ionomer to the water production process in PEMFCs.…”

Section: Pt and Ionomer Dissolutionmentioning

confidence: 99%

“…The effect of relative humidity on the degradation of PEMFC was previously associated to a number of factors such as membrane swelling [221,230], membrane thinning [231,232], creep formation and cracking [74,233], fluoride concentration change [30,75,201,341], catalyst particles migration [67,68], carbon corrosion [48,69,244,245], pin-hole formation [228][229][230]234], hydrogen crossover [36,70,75] and local fuel starvation [195,196,246,247].…”

Section: Contaminationmentioning

confidence: 99%

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Degradation aspects of water formation and transport in Proton Exchange Membrane Fuel Cell: A review

Ous

Arcoumanis

2013

Journal of Power Sources

130

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This is the accepted version of the paper.This version of the publication may differ from the final published version. Permanent repository link AbstractThis review paper summarises the key aspects of Proton Exchange Membrane Fuel Cell (PEMFC) degradation that are associated with water formation, retention, accumulation, and transport mechanisms within the cell. Issues related to loss of active surface area of the catalyst, ionomer dissolution, membrane swelling, ice formation, corrosion, and contamination are also addressed and discussed. The impact of each of these water mechanisms on cell performance and durability was found to be different and to vary according to the design of the cell and its operating conditions. For example, the presence of liquid water within Membrane Electrode Assembly (MEA), as a result of water accumulation, can be detrimental if the operating temperature of the cell drops to sub-freezing.The volume expansion of liquid water due to ice formation can damage the morphology of different parts of the cell and may shorten its life-time. This can be more serious, for example, during the water transport mechanism where migration of Pt particles from the catalyst may take place after detachment from the carbon support. Furthermore, the effect of transport mechanism could be augmented if humid reactant gases containing impurities poison the membrane, leading to the same outcome as water retention or accumulation.Overall, the impact of water mechanisms can be classified as aging or catastrophic. Aging has a longterm impact over the duration of the PEMFC life-time whereas in the catastrophic mechanism the impact is immediate. The conversion of cell residual water into ice at sub-freezing temperatures by the water retention/ accumulation mechanism and the access of poisoning contaminants through the water transport mechanism are considered to fall into the catastrophic category. The effect of water mechanisms on PEMFC degradation can be reduced or even eliminated by (a) using advanced materials for improving the electrical, chemical and mechanical stability of the cell components against deterioration, and (b) implementing effective strategies for water management in the cell.

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“…On the one hand, the ageing processes in the catalyst layer are modelled using ab-initio molecular dynamics approaches, which require suitable computing resources and the calculations are very timeconsuming. On the other hand, model assumed that the degradation phenomena in the polymer electrolyte membrane are negligible, although, the numerous studies demonstrated that, at conventional operating condition, the PEMFC damage is significantly affected by a chemical destruction of the polymer electrolyte membrane [18,19,32]. It should be mentioned, that the recent theoretical study [45] on the influence of material properties on the PEMFC performance showed that, the changes in the membrane characteristics substantially impact the PEMFC behaviour.…”

Section: Nomenclaturementioning

confidence: 99%

Membrane degradation model for 3D CFD analysis of fuel cell performance as a function of time

Karpenko-Jereb

Sternig

Fink

et al. 2016

International Journal of Hydrogen Energy

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Available online xxxKeywords: Polymer electrolyte fuel cell Nafion degradation Modelling Computational fluid dynamics Local operating condition a b s t r a c t The paper describes a development of a degradation model, which enables to predict timedependent changes in performance of a polymer electrolyte fuel cell. The developed model consists of two main parts: 1) a new semi-empirical model taking into account changes in physico-chemical properties of a polymer electrolyte membrane operating in the fuel cell, 2) a validated CFD model computing the 3D performance of the cell. In the semi-empirical model, the degradation rates of the membrane thickness and conductivity depend on the oxygen crossover rate. The acid group concentration is calculated from the membrane conductivity based on the percolation theory approach. The gas diffusion coefficients are modelled empirically as a function of the membrane thickness. The model of the membrane degradation is coupled with the CFD model and applied to analyse the cell behaviour as a function of time. The simulation shows that the cell current density decreases faster with lowering relative humidity and increasing temperature. The in-plane degradation of the membrane is non-uniform and depends on the local operating condition.

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Open circuit voltage durability study and model of catalyst coated membranes at different humidification levels

Cited by 16 publications

References 34 publications

Investigation of catalyst layer defects in catalyst-coated membrane for PEMFC application: Non-destructive method

Investigation of catalyst layer defects in catalyst-coated membrane for PEMFC application: Non-destructive method

Degradation aspects of water formation and transport in Proton Exchange Membrane Fuel Cell: A review

Membrane degradation model for 3D CFD analysis of fuel cell performance as a function of time

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