Influence of the solvent in anode catalyst ink on the performance of a direct methanol fuel cell

Kim, Joon-Hee; Ha, Heung Yong; Oh, In‐Hwan; Hong, Seung‐Chyul; Lee, Ho‐In

doi:10.1016/j.jpowsour.2004.03.058

Cited by 63 publications

(21 citation statements)

References 19 publications

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“…[8][9][23][24][25][26][27][28][29][30][31][32] Unfortunately, none of these results are directly comparable to each other due to different components studied. While this solvent effect on cast properties has been 4 established, there is currently a lack of understanding of the interactions between the catalyst, solvent, and PFSA present in the ink.…”

Section: Introductionmentioning

confidence: 99%

Inherent Acidity of Perfluorosulfonic Acid Ionomer Dispersions and Implications for Ink Aggregation

2018

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Perfluorosulfonic-acid (PFSA) dispersions are used as components in a variety of electrochemical technologies, particularly in fuel-cell catalyst-layer inks. In this study, we characterize dispersions of a common PFSA, Nafion, as well as inks of Nafion and carbon. It is shown that solvent choice affects a dispersion's measured pH, which is found to scale linearly with Nafion loading. Dispersions in water-rich solvents are more acidic than those in propanolrich solvents: a 90% water versus 30% water dispersion can have up to a 55% measured proton deviation. Furthermore, because electrostatic interactions are a function of pH, these differences affect how particles aggregate in solution. Despite having different water contents, all inks studied demonstrate the same particle size and surface charge trends as a function of pH, thus providing insights into the relative influence of solvent and pH effects on these properties.3

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Section: Introductionmentioning

confidence: 99%

Inherent Acidity of Perfluorosulfonic Acid Ionomer Dispersions and Implications for Ink Aggregation

2018

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“…Improvements in electrode structures, which are composed of catalysts and a sulfonated polymer, can greatly improve performances by increasing the efficiency of electrocatalysts [63][64][65][66][67][68]. A porous carbon support, Ketjenblack EC 300 J (KB), used as catalyst for DMFCs has been functionalized to give sulfonated polystyrene (sPS) groups on the carbon surface [69].…”

Section: Activation and Functionalization Of Carbon Blacksmentioning

confidence: 99%

Carbon-Based Nanomaterials

Lavacchi

Vizza

2013

Nanostructure Science and Technology

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In fuel cells both the anode and cathode electrocatalysts are generally composed of nanosized metal particles which are supported on high surface area materials. The electrochemically active surface area (EASA), of catalysts used in low temperature fuel cells, such as polymer electrolyte membrane fuel cells (PEMFC, fed with hydrogen), direct alcohol fuel cells (DAFCs, alcohols: ethanol, methanol, polyalcohols), and direct formic acid fuel cells (DFAFC), has been found to be greatly enhanced when high surface area carbon-based materials are used as the support. As described in detail in Chap. 3, at the anode of a PEMFC dihydrogen is oxidized yielding protons and electrons. The protons pass through the cation exchange membrane toward the cathode where they are used in the reduction of oxygen to water together with the electrons arriving from the anode. The use of an anionexchange polymeric membrane as electrolyte, i.e., a membrane which allows only negative charges to pass, favors the production of negative ions, in this case OH -, in the process of oxygen reduction at the cathode, while the overall electrochemical process is left unvaried, as well as the reversible voltage of the cell. In PEMFCs, the polymeric electrolyte is generally Nafion Ò , a proton-exchange fluorinated membrane, about 50-200 lm thick. This withholds negatively charged ions (usually sulfonate groups -SO 3 -) covalently bonded to the polymeric backbone and therefore allows the passage of protons. Electrons are therefore forced to flow through the outer circuit. Nafion Ò , like other proton-exchange polymeric membranes, is most efficient when it works between 70 and 100°C, thus limiting the functionality of PEMFCs to low temperature operation.In DAFCs at the anode alcohols are oxidized to yield protons, electrons, and CO 2 or carboxylates, depending on the nature of the alcohol used as a fuel, while the cathode process is wholly similar to the one that takes place in PEMFCs.The most important component of a fuel cell is the membrane electrode assembly (MEA) that is composed of a catalytic layer where the electrochemical reactions occur, a diffusion layer providing access to the fuel and oxygen to the catalytic layer and a membrane where ions flow from one electrode to the other.

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“…Kim et al (2004) studied the particle size distribution of Nafion ® ionomer using the dynamic light scattering (DLS) method and observed changes in the peak position in the region corresponding to 0.04-0.8 µm. Thus, the first peak was believed to come from the particle size distribution of Nafion ® ionomer in the dispersion solvent (Kim et al, 2004), for which similar results were also observed by Lim et al (2006) As a result, the second peak was thought to contribute to the agglomerate size distribution. This clearly showed that by increasing homogenization time, the agglomerate size could be decreased.…”

Section: Determination Of Catalyst Agglomerate Size In Catalyst Inkmentioning

confidence: 99%

Modeling for PEFC MEAs Based on Reaction Rate on Pt Surface and Microstructures of Catalyst Layers

Limjeerajarus

Nishiyama

Ohashi

et al. 2009

J. Chem. Eng. Japan

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A polymer electrolyte fuel cell membrane electrode assembly (PEFC MEA) model that focuses on the structural and reaction parameters of catalyst layers has been developed. The reaction and structural parameters were modeled independently by considering the oxygen reduction reaction (ORR) activity in terms of current per unit active surface area of Pt [A cm -2 -Pt]. The catalyst layer models were constructed based on an assumption of cylindrical secondary pore structure, which was verified by measuring the primary pore size using mercury porosimetry. We found that penetration of Nafion ® electrolyte into the primary pores of Pt/C catalysts was restricted, and thus diffusion and reaction in primary pores became negligible. Moreover, the experimental results demonstrated that for the same catalyst, ORR activity remained almost constant, irrespective of the agglomerate size (i.e., 2.7 × × × × × 10 -6 A cm -2 -Pt at 60°C for Pt/C TEC10E50E in this study). This supported our idea that reaction parameters and structural parameters should be considered independently in PEFC modeling. The cell performance predicted with the developed model was satisfactorily accurate as compared to that obtained from experiments. As a result, the modeling developed in this study can be used to construct simple PEFC models that yield results with good accuracy and can be a useful tool for the development of PEFCs in future.

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Influence of the solvent in anode catalyst ink on the performance of a direct methanol fuel cell

Cited by 63 publications

References 19 publications

Inherent Acidity of Perfluorosulfonic Acid Ionomer Dispersions and Implications for Ink Aggregation

Inherent Acidity of Perfluorosulfonic Acid Ionomer Dispersions and Implications for Ink Aggregation

Carbon-Based Nanomaterials

Modeling for PEFC MEAs Based on Reaction Rate on Pt Surface and Microstructures of Catalyst Layers

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