Effect of High Oxygen Permeable Ionomers on MEA Performance for PEFC

Yamada, Kazutoyo; Hommura, Satoru; Shimohira, Tetsuji

doi:10.1149/05002.1495ecst

Cited by 19 publications

(11 citation statements)

References 11 publications

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“…Several research groups have reported significant improvements in fuel cell performance without any remarkable adverse effects by using highly oxygen-permeable ionomers (HOPIs) 38 – 41 . For example, a recent study by Katzenberg et al 41 showed that a HOPI incorporating an oxygen-permeable glassy amorphous matrix based on a perfluoro-(2-methylene-4-methyl-1,3-dioxolane) (PFMMD) backbone shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

The role of oxygen-permeable ionomer for polymer electrolyte fuel cells

et al. 2021

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In recent years, considerable research and development efforts are devoted to improving the performance of polymer electrolyte fuel cells. However, the power density and catalytic activities of these energy conversion devices are still far from being satisfactory for large-scale operation. Here we report performance enhancement via incorporation, in the cathode catalyst layers, of a ring-structured backbone matrix into ionomers. Electrochemical characterizations of single cells and microelectrodes reveal that high power density is obtained using an ionomer with high oxygen solubility. The high solubility allows oxygen to permeate the ionomer/catalyst interface and react with protons and electrons on the catalyst surfaces. Furthermore, characterizations of single cells and single-crystal surfaces reveal that the oxygen reduction reaction activity is enhanced owing to the mitigation of catalyst poisoning by sulfonate anion groups. Molecular dynamics simulations indicate that both the high permeation and poisoning mitigation are due to the suppression of densely layered folding of polymer backbones near the catalyst surfaces by the incorporated ring-structured matrix. These experimental and theoretical observations demonstrate that ionomer’s tailored molecular design promotes local oxygen transport and catalytic reactions.

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Section: Introductionmentioning

confidence: 99%

The role of oxygen-permeable ionomer for polymer electrolyte fuel cells

et al. 2021

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“…Perfluorosulfonated ionomers containing dioxole segments have been reported as catalyst binder in CCL by several research groups. − The existing sulfonic acid groups guarantee the proton conductivity of ionomers, whereas the presence of rigid dioxole rings in the amorphous perfluoropolymers prevents the stacking of polymer chains, resulting in a relatively significant amount of free volume, which in turn provides a high oxygen permeability. Both experimental and theoretical observations revealed that the high solubility of oxygen in the dioxole-containing perfluorinated ionomers can enhance the oxygen permeation through the ionomer–Pt interface and improve the power density of the accordingly assembled fuel cells .…”

Section: Introductionmentioning

confidence: 99%

Tailoring Ionomer Chemistry for Improved Oxygen Transport in the Cathode Catalyst Layer of Proton Exchange Membrane Fuel Cells

Fang

Liu

et al. 2023

ACS Appl. Energy Mater.

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Reducing the local oxygen transport resistance in the cathode catalyst layer of the proton exchange membrane fuel cell (PEMFC) is crucial for the improvement of cell performance, particularly for low platinum loading. In this work, we report that the performance of PEMFC can be significantly improved by replacing Nafion with a highly oxygen-permeable perfluoronated ionomer containing dioxole segments on the backbone as both proton conductor and catalyst binder in the cathode catalyst layer, as evidenced by the increased peak power density of 100 mW cm −2 . Molecular dynamics simulation results reveal that the synthesized ionomer has higher diffusion coefficient and higher oxygen solubility compared with Nafion. Benefiting from the high oxygen permeability, both the specific activity and mass specific activity of a Pt/C catalyst using the designed ionomer as catalyst binder for the oxygen reduction reaction are three times higher than those of a catalyst using Nafion as catalyst binder. The results demonstrate that the rational design of highly oxygen-permeable ionomers applied in the catalyst layer could be an effective strategy for a highperformance PEMFC with low platinum loading.

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“…Shimizu et al [17] used two types of HOPIs that showed an improvement of 150 mV in cell voltage at 1.5 A cm −2 , but the catalyst layers had low durability. Yamada et al [18] reported two HOPIs that showed significant improvement compared to a Reference ionomer, but did not share the HOPI structure, nor the Reference ionomer. Kodama [19] demonstrated improved performance using HOPIs with PDD and PFSVE, along with detailed analysis of the oxygen resistance and extensive models of the HOPI structure and behavior.…”

Section: Introductionmentioning

confidence: 99%

Highly Durable Fluorinated High Oxygen Permeability Ionomers for Proton Exchange Membrane Fuel Cells

Macauley

Lousenberg

Spinetta

et al. 2022

Advanced Energy Materials

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For proton exchange membrane fuel cells to be cost‐competitive in light‐ and heavy‐duty vehicle applications, their Pt content in the catalyst layers needs to be lowered. However, lowering the Pt content results in voltage losses due to high local oxygen transport resistances at the ionomer–Pt interface. It is therefore crucial to use ionomers that have higher oxygen permeability than Nafion. In this work, novel high oxygen permeability ionomers (HOPIs) are presented, with up to five times higher oxygen permeability than Nafion, synthesized by copolymerization of perfluoro‐2,2‐dimethyl‐1,3‐dioxole (PDD) with perfluoro(4‐methyl‐3,6‐dioxaoct‐7‐ene) sulfonyl fluoride (PFSVE). PDD is the source of higher permeability due to its open ring structure, while PFSVE provides ionic conductivity. Optimization of PDD content and equivalent weight enables increased fuel cell performance, mainly at high current densities, where HOPIs can achieve power densities >1.25 W cm−2 and exceed the 0.8 A cm−2 U.S. Department of Energy durability target by losing only 4.5 mV, which is over six times less than 30 mV. The interactions between HOPI and SO3− groups with a PtCo/C catalyst are also elucidated here at a fundamental level.

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Effect of High Oxygen Permeable Ionomers on MEA Performance for PEFC

Cited by 19 publications

References 11 publications

The role of oxygen-permeable ionomer for polymer electrolyte fuel cells

The role of oxygen-permeable ionomer for polymer electrolyte fuel cells

Tailoring Ionomer Chemistry for Improved Oxygen Transport in the Cathode Catalyst Layer of Proton Exchange Membrane Fuel Cells

Highly Durable Fluorinated High Oxygen Permeability Ionomers for Proton Exchange Membrane Fuel Cells

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