Transport and equilibrium properties of Nafion® membranes with H+ and Na+ ions

Okada, Tatsuhiro; Møller-Holst, Steffen; Gorseth, Oddvar; Kjelstrup, Signe

doi:10.1016/s0022-0728(97)00499-3

Cited by 180 publications

(186 citation statements)

References 23 publications

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“…Once the cations enter the ionomer, they displace protons resulting in reduced ionic conductivity and water content, as well as lower gas permeability of the ionomer. 5,6,[13][14][15][16][17][18] Other researchers confirmed the findings of Okada group as well. 9,20,25,31,33 23 Pozio et al 19 investigated the degradation in PEFC that was caused by iron contamination from SS316L end plates and reported that contamination of the membrane electrode assemblies with iron led to degradation of the ionomer, revealed by a massive fluoride losses.…”

supporting

confidence: 61%

Thinning of Cathode Catalyst Layer in Polymer Electrolyte Fuel Cells Due to Foreign Cation Contamination

Banas

Uddin

Park

et al. 2018

J. Electrochem. Soc.

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Four hundred hour fuel cell tests were performed on commercial, as-received and Ca 2+ contaminated catalyst coated membranes (CCMs) to evaluate the effects of long term exposure of foreign cations on fuel cell performance and degradation. Following testing, significant thinning of the cathode catalyst layer was observed across the entire active area in the contaminated cell, while only localized thinning was observed in the as-received baseline CCM. Analysis of the elemental maps and line intensity profiles of platinum (Pt) obtained from energy dispersive X-ray spectrum (EDX) shows minimal change in total platinum content across the thickness of the catalyst layer, and hence loss of carbon is suspected to be the cause of the thinning. A numerical model is employed to show the foreign cation redistribution during testing, which shows proton depletion in the cathode catalyst layer when the CCM is contaminated with foreign cations. We hypothesize that this lack of protons leads to accelerated carbon corrosion in the cathode to supply protons to oxygen reduction where foreign cations block transport of protons. A carbon corrosion scheme is presented which shows that under the operating potentials of the cell, carbon oxidation can occur, leading to the observed thinning. The polymer electrolyte fuel cell (PEFC), a promising clean energy source for automobile application, still needs to overcome durability issues originating from various sources.1 Cationic impurities originated from either ambient air (e.g. roadside contaminants) or from the corrosion of stack and balance of plant components can significantly decrease the performance and life time of PEFCs. [1][2][3][4] In this paper, we report on the influence of foreign cationic contamination on the thinning of the cathode catalyst layer during non-accelerated testing. Long duration (400hr) testing was conducted using commercial catalyst coated membranes which showed significant catalyst layer thinning in a calcium cation contaminated cell, this thinning of the cathode catalyst layer was not observed in a non-contaminated baseline. While foreign cations are known to cause several degradation mechanisms in PEFCs, no study has examined the influence of cationic contamination on carbon corrosion, which we believe causes the thinning of the catalyst layer.To understand the impact and mechanism of cation contamination in PEFC, several modeling 5-11 and experimental studies 12-33 have been conducted, including ex-situ contamination of the polymer membrane with various cations before the test as well as injecting cations into the air or fuel stream during the cell test. Okada and co-workers extensively investigated the effect of various metal cations (Li + , Na + , Ca 2+ , Fe 2+ , Ni 2+ , Cu 2+ , Rb 2+ , Cs + ) on the transport properties of perfluorosulfonic acid (PFSA) membranes, thermodynamics and oxygen reduction reaction (ORR) kinetics. 5,[13][14][15][16][17][18] They reported that, with the exception of Li + , all foreign cations have higher affinity toward the sulfo...

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supporting

confidence: 61%

Thinning of Cathode Catalyst Layer in Polymer Electrolyte Fuel Cells Due to Foreign Cation Contamination

Banas

Uddin

Park

et al. 2018

J. Electrochem. Soc.

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“…The literature contains several research publications on metal ion contamination in fuel cells [18][19][20][21]. In our recent study using a conventional electrochemical cell [14], we concluded that Co 2+ , which arises from dissolution of the PtCo alloy catalyst used in the fuel cell cathode reaction, could have a significant detrimental effect on the ORR kinetics through surface adsorption on the Pt catalyst surface, leading to deterioration of the ORR reaction.…”

Section: Introductionmentioning

confidence: 91%

PEM fuel cell cathode contamination in the presence of cobalt ion (Co2+)

Gazzarri

Tsay

et al. 2010

Electrochimica Acta

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was injected into the cathode air stream, and Co 2+ contamination became more severe with decreasing temperature. To investigate in detail the mechanism of Co 2+ poisoning, AC impedance was monitored before and during Co 2+ injection, revealing that both charge transfer and mass transport related processes deteriorated significantly in the presence of Co 2+ , whereas membrane conductivity decreased to a lesser extent. Surface cyclic voltammetry and contact angle measurements further revealed changes in physical properties, such as active Pt surface area and hydrophilicity, furthering our understanding of the contamination process.Crown

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“…While few studies have looked at how metal ions affect catalyst activity [18,19,23,24], we believe it is necessary to initiate such an investigation, particularly in the case of Pt alloys being used as the cathode ORR catalyst, where a second alloy metal such as Co could leach out during fuel cell operation. In the current state of PEM fuel cell technology, Pt alloys are a new generation of cathode ORR catalysts, mainly because they exhibit higher ORR activity/stability and contain less Pt than pure Pt catalysts.…”

Section: Introductionmentioning

confidence: 99%

Effect of Co2+ on oxygen reduction reaction catalyzed by Pt catalyst, and its implications for fuel cell contamination

Tsay

Wang

et al. 2010

Electrochimica Acta

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The oxygen reduction reaction (ORR) catalyzed by Pt was studied in the presence of Co 2+ using cyclic voltammetry (CV), rotating disk electrode (RDE), and rotating ring-disk electrode (RRDE) techniques in an effort to understand fuel cell cathode contamination caused by Co 2+ . Findings indicated that Co 2+ could weakly adsorb on the Pt surface, resulting in a slight change in ORR exchange current densities. However, this weak adsorption had no significant effect on the nature of the ORR rate determining steps. The results from both RDE and RRDE indicated that the overall electron transfer number of the ORR in the presence production. The fuel cell performance drop observed in the presence of Co 2+ could be attributed to the reduction in overall electron transfer number and the increase in H 2 O 2 production. Higher production could intensify the attack by H 2 O 2 and its radicals on membrane electrode assembly components, including the ionomer, carbon support, Pt particles, and membrane, leading to fuel cell degradation.Crown

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Transport and equilibrium properties of Nafion® membranes with H+ and Na+ ions

Cited by 180 publications

References 23 publications

Thinning of Cathode Catalyst Layer in Polymer Electrolyte Fuel Cells Due to Foreign Cation Contamination

Thinning of Cathode Catalyst Layer in Polymer Electrolyte Fuel Cells Due to Foreign Cation Contamination

PEM fuel cell cathode contamination in the presence of cobalt ion (Co2+)

Effect of Co2+ on oxygen reduction reaction catalyzed by Pt catalyst, and its implications for fuel cell contamination

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