Nafion content in the catalyst layer of polymer electrolyte fuel cells: effects on structure and performance

Passalacqua, E.; Lufrano, F.; Squadrito, Gaetano; Patti, Antonio F.; Giorgi, L.

doi:10.1016/s0013-4686(00)00679-4

Cited by 413 publications

(257 citation statements)

References 13 publications

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“…Experimental evidence also supports the picture in Figure 7 of an agglomerate-type structure where the electrocatalyst is supported on a carbon clump and is covered by a thin layer of membrane, which may then be covered by a thin film of liquid water. [110][111][112][113][114] Figure 7 is an idealized picture, and the actual structure is probably more of a "spaghetti and meatball" structure, where the carbon agglomerates are connected to each other and covered by thin tendrils of membrane.…”

Section: Catalyst-layer Modelingmentioning

confidence: 99%

Modeling Water Management in Polymer-Electrolyte Fuel Cells

Weber

Balliet

Gunterman

et al. 2008

Modern Aspects of Electrochemistry

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Section: Catalyst-layer Modelingmentioning

confidence: 99%

Modeling Water Management in Polymer-Electrolyte Fuel Cells

Weber

Balliet

Gunterman

et al. 2008

Modern Aspects of Electrochemistry

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“…the dry weight of Nafion ionomer divided by the geometric area of the electrode or as wt% of Nafion (dry weight of Nafion ionomer divided by the total weight of Pt + C and Nafion ionomer, multiplied by 100 [13]). The optimum Nafion content reported in the literature is generally in the range of 30-36 wt% irrespective of the Pt loading on Vulcan XC-72 for PEMFCs [11,[16][17][18], while the optimal Nafion content seems to be ca. 22 wt% for DMFCs [19] Although many studies have reported the effect of the Nafion content, somewhat different optimum Nafion contents are reported by different researchers.…”

mentioning

confidence: 94%

The Influence of Pt Loading, Support and Nafion Content on the Performance of Direct Methanol Fuel Cells: Examined on the Example of the Cathode

et al. 2011

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Nano‐sized Pt colloids were prepared using the polyol method and supported on Ketjen black EC 600J (KB), Vulcan XC‐72 (VC) and high surface area graphite 300 (HG). The effects of the Nafion ionomer content, and the Pt loading of the cathode catalyst layer as well as the Pt loading on the support on the performance of direct methanol fuel cells (DMFCs), were studied. The membrane electrode assemblies (MEAs) were analysed using current–voltage curves, cyclic voltammetry, electrochemical impedance spectroscopy (EIS) and adsorbed CO stripping voltammetry. Optimum Nafion to carbon (N/C) ratios (N/C being defined as the weight ratio of the Nafion ionomer to the carbon) were determined. The optimum N/C ratios were found to depend on the support as follows, 1.4, 0.7 and 0.5 for Pt/KB, Pt/VC and Pt/HG, respectively and to be independent of the Pt/C loading range of 20–80 wt% tested in this work. The highest DMFC performances, as well as the highest electrochemical active surface areas, and improved gas diffusivities, were achieved using these ratios. For the catalysts prepared in this work, the average Pt crystallite size was found to decrease with increasing surface area of the support for a particular Pt loading. MEAs made using KB as support and the optimal N/C ratio of 1.4 showed the best performances, i.e. higher than the VC and HG supports for any N/C ratio. The highest DMFC performance was observed using 60 wt% Pt on KB cathode electrodes of 1 mg Pt cm–2 loading and an N/C value of 1.4. For all three supports studied, the 60 wt% Pt on carbon loading resulted in the best DMFC performance. This may be linked to the Pt particle size and catalyst preparation method used in this work. In comparison to literature results, high DMFC performances were achieved using relatively ‘low' Pt and Ru loadings. For example, a maximum power density of >100 mW cm–2 at 60 °C was observed using a 1 mg Pt cm–2 cathode loading and a 2 mg PtRu cm–2 anode loading.

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“…The volumetric ionomer content affects the reaction rate because it controls the pathways for oxygen and proton to diffuse in the agglomerate (Passalacqua et al, 2001). The effective diffusion coefficient of the agglomerate for dissolved oxygen is often assumed to depend on its ionomer content θ in…”

Section: Resultsmentioning

confidence: 99%