Study on the Cathode Fabricated by Spinning Process and Its Performance in PEFC

Kotera, Seigo; Watabe, Hiroyuki; Fujii, Katsuya; Terada, Ichro; Matsubara, Chie; Uyama, Hiroshi

doi:10.1149/1.3210635

Cited by 6 publications

(4 citation statements)

References 4 publications

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“…To improve fuel cell performance, several studies have explored various alternate catalyst layer morphologies − to the conventional catalyst-coating layers with random morphologies . Electrospun nanofiber catalyst layer morphologies have recently attracted interest due to improved performance and durability compared to the conventional morphology. ,− These enhancements have been attributed to better dispersion of catalyst and ionomer phases, which maximizes the three-phase interaction (carbon–ionomer–catalyst interface) and thus increases catalyst utilization, and increased porosity (due to interfiber void fraction) that enhances the mass transport properties of the catalyst layer. ,, …”

Section: Introductionmentioning

confidence: 99%

“…3,6−10 These enhancements have been attributed to better dispersion of catalyst and ionomer phases, which maximizes the threephase interaction (carbon−ionomer−catalyst interface) and thus increases catalyst utilization, and increased porosity (due to interfiber void fraction) that enhances the mass transport properties of the catalyst layer. 8,10,11 Electrospinning is one of the common techniques to fabricate nanofiber catalyst layers. It allows fiber fabrication from a diverse set of materials and can produce fibers with a wide range of diameters.…”

Section: ■ Introductionmentioning

confidence: 99%

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Toward Optimizing Electrospun Nanofiber Fuel Cell Catalyst Layers: Polymer–Particle Interactions and Spinnability

Khandavalli

Sharma-Nene

Kabir

et al. 2021

ACS Appl. Polym. Mater.

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We investigate the effect of the poly(acrylic acid) (PAA) carrier polymer concentration on the microstructure and rheological properties of catalyst inks for electrospun polymer−electrolyte membrane fuel-cell catalyst layers. Characterization of an ink microstructure using oscillatory shear rheology showed that the catalyst particles (platinum on carbon) are significantly agglomerated in the absence of PAA or an ionomer. Both the ionomer and PAA promoted the stability of the particles against agglomeration via electrosteric stabilization by adsorbing onto the particle surface. Increasing the PAA concentration increased the stability of the particles (or reduced the agglomerated structure) due to increasing PAA coverage onto the free surface area of the particles. However, beyond a certain increase in concentration, PAA was found to predominantly remain as an excess free polymer in the ink due to an insufficient free/available surface area on the particles for further PAA coverage. Extensional rheology measurements demonstrated that PAA enhances the extensional viscosities of the inks. Consequently, increasing the PAA concentration in the ink promoted the evolution of uniform nanofibers. However, beyond a certain concentration, a significant increase in the shear viscosities of the inks led to defective fiber morphologies because of the onset of flow instabilities. Electrochemical performance comparisons between catalyst layers with different PAA concentrations showed maximum performance at the PAA concentration that led to the least agglomerated structure of the catalyst, most uniform fiber morphologies, and low concentrations of free (nonadsorbing) PAA in the electrode. These results provide a rationale for optimization of electrospun catalyst nanofibers for both spinnability and electrochemical performance.

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Section: Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Toward Optimizing Electrospun Nanofiber Fuel Cell Catalyst Layers: Polymer–Particle Interactions and Spinnability

Khandavalli

Sharma-Nene

Kabir

et al. 2021

ACS Appl. Polym. Mater.

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“…This was reflected in lower mass transfer losses during fuel cell operation under 100% RH, 95 °C, and 150 kPa backpressure. 26 Hong et al fabricated the electrode with an ultralow Pt loading (0.087 mg Pt cm −2 ), poly(acrylic acid) (PAA), and Nafion with a 5% PTFE additive with a maximum output of 0.692 W cm −2 . The reported fiber-based electrode was shown to have 1.06-fold higher performance than the decal electrode loading with 0.18 mg Pt cm −2 .…”

Section: ■ Introductionmentioning

confidence: 99%

“…As a result, the fibrous electrodes outperformed the classical electrodes, exhibiting 10 times more porosity and gas permeability. This was reflected in lower mass transfer losses during fuel cell operation under 100% RH, 95 °C, and 150 kPa backpressure . Hong et al fabricated the electrode with an ultralow Pt loading (0.087 mg Pt cm –2 ), poly(acrylic acid) (PAA), and Nafion with a 5% PTFE additive with a maximum output of 0.692 W cm –2 .…”

Section: Introductionmentioning

confidence: 99%

Electrospun Nanofiber Electrodes for Boosted Performance and Durability at Lower Humidity Operation of PEM Fuel Cells

et al. 2022

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The need for the development of new materials and strategies to enhance the performance of the PEM fuel cell at low humidity and platinum (Pt) loadings is becoming increasingly crucial. Due to this fact, the current study presents the fabrication of electrospun sulfonated silica (S-SiO 2 ) as a poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE))-based, flexible, freestanding, and highly porous novel cathode structure for PEM fuel cells. The developed fiber-based P(VDF-TrFE)/Pt/C/S-SiO 2 cathodes are compared with electrospun PVDF/Pt/C/S-SiO 2 , PVDF/Pt/C/Nafion, and conventionally sprayed electrodes to evaluate the utility of a new (carrier) P(VDF-TrFE) polymer in electrode structure. Morphological analyses revealed that S-SiO 2 and Pt/C particles were homogeneously distributed along the fibers without any significant agglomerations. The MEAs prepared by fiber-based P(VDF-TrFE)-Pt/C/S-SiO 2 cathodes with low Pt loadings (0.1−0.15 mg cm Pt −2) demonstrated promising fuel cell performance recording up to 417.7 mW cm −2 . It also exhibited a remarkable power output retention (98.2%) under partially humidified conditions. In situ electrochemical measurements reveal that enhanced particle distribution and Pt/S-SiO 2 surface contact results in the cathode performance surpassing that of conventional sprayed and fiber-based PVDF/Pt/C/Nafion cathodes. The fiber-based P(VDF-TrFE)/Pt/C/S-SiO 2 cathodes exhibited a promising durability record retaining up to 86.5% of their maximum power output after 30 000 cycles of a Pt-dissolution accelerated stress test (AST). Furthermore, P(VDF-TrFE)-Pt/C/S-SiO 2 cathodes with high S-SiO 2 loadings exhibited a 2.7% gain in maximum power density after 1000 cycles of a carbon corrosion durability test.

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High‐Performance Nanofiber Fuel Cell Electrodes

2011

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A nanofiber electrode is fabricated by electrospinning an ink composed of Pt/C catalyst particles in a solution of Nafion and poly(acrylic acid). Exceptionally high power densities and platinum mass activity are achieved when using the mat as cathode in H2/air and H2/O2 fuel cell membrane–electrode assemblies. The nanofiber cathode also exhibits outstanding stability in accelerated durability tests.

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Study on the Cathode Fabricated by Spinning Process and Its Performance in PEFC

Cited by 6 publications

References 4 publications

Toward Optimizing Electrospun Nanofiber Fuel Cell Catalyst Layers: Polymer–Particle Interactions and Spinnability

Toward Optimizing Electrospun Nanofiber Fuel Cell Catalyst Layers: Polymer–Particle Interactions and Spinnability

Electrospun Nanofiber Electrodes for Boosted Performance and Durability at Lower Humidity Operation of PEM Fuel Cells

High‐Performance Nanofiber Fuel Cell Electrodes

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