Measurements of proton conductivity in the active layer of PEM fuel cell gas diffusion electrodes

Boyer, C.; Gamburzev, S.; Velev, O.; Srinivasan, S.; Appleby, A.J.

doi:10.1016/s0013-4686(98)00128-5

Cited by 135 publications

(105 citation statements)

References 9 publications

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“…Figure 12 shows a plot of the proton conductivity (r p ) vs. the Vol.% of Nafion. A similar plot has been presented by Havránek et al [24] for MEA anodes made of unsupported catalysts and by Boyer et al [29]. Similar to Havránek et al, the relationship between r p vs. the Vol.% of Nafion obtained for these electrodes is not linear.…”

Section: R P and R P Values For Stenciled Vs Sprayed Anodessupporting

confidence: 78%

“…The n values estimated in this manner are listed in Table 4. Typical n values range from 1.2 to 4.5 [24,29], i.e., the values for the 10-40 wt.% (i.e., 8-28 Vol.%) Nafion are well within the typical range observed. An n value of unity indicates a phase of no tortuosity.…”

Section: R P and R P Values For Stenciled Vs Sprayed Anodessupporting

confidence: 57%

“…The r p values are one order of magnitude lower than found for bulk Nafion, which is reported as 120 mS cm -1 at 40°C [ 24]. As discussed in previous work, this difference can be explained by the tortuosity of the Nafion phase in the catalyst layer [29].…”

Section: R P and R P Values For Stenciled Vs Sprayed Anodesmentioning

confidence: 56%

“…The influence of lower Vol.% amounts of Nafion onto the proton conductivity was not tested, as the Vol.% of Nafion of less than 8 was too small to make a mechanically stable electrode. The r p values and the following empirical equation were used to obtain more information about the micro-structure and tortuosity of the Nafion phase [29]:…”

Section: R P and R P Values For Stenciled Vs Sprayed Anodesmentioning

confidence: 99%

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DMFC electrode preparation, performance and proton conductivity measurements

et al. 2008

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A method that involves stenciling electrodes using dry powders for fuel cells is described and compared to anodes and cathodes prepared by the traditional spraying method using catalyst inks. Methods to determine the proton conductivity of the DMFC anode layer are also discussed. The stenciling method allows for the preparation of highly reproducible membrane electrode assemblies (MEAs) utilizing little waste material. MEAs can be prepared in a controlled manner using the stenciling technique. The resulting morphology of the as-prepared electrodes is observed to be dependent on the preparation method, while the thickness of the once hot-pressed catalyst layers appears to be independent of the preparation method. Stenciled anodes of the same catalyst loading were found to show a lower proton resistance (R p ) than sprayed anodes. However, the lower R p value was not sufficient to result in a measurable increase in the performance of a direct methanol fuel cell (DMFC); as in fact, the average steady-state DMFC performance was found to be the same using sprayed or stenciled electrodes. The DMFC performance was found to be strongly dependent on the Nafion content and large increases in the Nafion content were needed to increase the DMFC performance measurably. Even though thick electrodes were prepared in this work, the R p values of the stenciled anodes were found to be comparable to results reported in the literature for much thinner electrodes made using high metal catalyst loadings on carbon. This observation is most probably due to the higher Nafion content used in this work.

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Section: R P and R P Values For Stenciled Vs Sprayed Anodessupporting

confidence: 78%

Section: R P and R P Values For Stenciled Vs Sprayed Anodessupporting

confidence: 57%

Section: R P and R P Values For Stenciled Vs Sprayed Anodesmentioning

confidence: 56%

Section: R P and R P Values For Stenciled Vs Sprayed Anodesmentioning

confidence: 99%

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DMFC electrode preparation, performance and proton conductivity measurements

et al. 2008

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“…It has been applied to a wide range of different fields as fuel cells [5][6][7][8][9][10], batteries [11][12], coatings [13][14], electrochemical reaction kinetics [15], electrochemical sensors [16][17][18][19], supercapacitors [20][21][22] and dielectrics [23]. This electrochemical measurement technique has also been used in fields that are not traditionally linked to electrochemistry as enzymatic kinetics [24], cancer detection [25], biochemistry [26][27] and immunology [28][29] amongst others.…”

Section: Introductionmentioning

confidence: 99%

Total harmonic distortion based method for linearity assessment in electrochemical systems in the context of EIS

Giner-Sanz

Ortega

Pérez-Herranz

2015

Electrochimica Acta

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ElsevierGiner Sanz, JJ.; Ortega Navarro, EM.; Pérez-Herranz, V. (2015). Total harmonic distortion based method for linearity assessment in electrochemical systems in the context of EIS. Electrochimica Acta. 186:598-612. doi:10.1016Acta. 186:598-612. doi:10. /j.electacta.2015 Electrochemical Impedance Spectroscopy (EIS) is a widely used electrochemical measurement technique that has been used in a great spectrum of fields since it allows deconvolving the individual physic-chemical processes that take place in a given system. Ohm's generalized law, and thus the impedance concept, are only valid if 4 conditions are fulfilled: causality, finiteness, stationarity and linearity. In the case that any of these conditions is not achieved, the obtained impedance spectra will present distortions that may lead to biased or even erroneous results and conclusions. For this reason it is crucial to verify if the 4 conditions are fulfilled, before accepting the results extracted from impedance spectra. In this work, a linearity assessment quantitative method based in the total harmonic distortion (THD) parameter is presented and verified experimentally. The experimental validation of the implemented method showed that the implemented method is able to assess quantitatively the linearity of the system. In addition, it is also able to determine the threshold frequency above which the system will not present significant nonlinear effects even for large perturbation amplitudes. It was observed that the THD method is more sensitive to nonlinear effects than the spectra themselves.

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Principles ofMEApreparation

Kocha¹

2010

Handbook of Fuel Cells

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A brief history of the evolution of the fuel cell electrode, emphasizing the technological developments that have lead to the contemporary polymer electrolyte membrane electrode assembly (MEA). This is followed by a discussion of the requirements, functions and properties of individual components and processes by which they are fabricated into MEAs. Lastly, basic in situ electrochemical techniques that may be applied as diagnostic tools to understand and advance the performance of MEA technology are reviewed.

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Measurements of proton conductivity in the active layer of PEM fuel cell gas diffusion electrodes

Cited by 135 publications

References 9 publications

DMFC electrode preparation, performance and proton conductivity measurements

DMFC electrode preparation, performance and proton conductivity measurements

Total harmonic distortion based method for linearity assessment in electrochemical systems in the context of EIS

Principles ofMEApreparation

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