Novel architectures for microporous layers without binding agent
April 2011
Now that the beneficial role of the microporous layer for water management in low-temperature fuel cells is better understood, the next question is about the relevance of current fabrication methods and composition of commercialized products: carbon blacks as well as PTFE, which make up most of the slurries, have increasingly proved a lack of reliability due to corrosion problems and gradual loss of hydrophobicity during fuel cell operation. Alternative structures are therefore being considered involving carbon nanofibers or nanotubes to replace both components as single self-standing or in situ-grown layers.
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April 2011
Now that the beneficial role of the microporous layer for water management in low-temperature fuel cells is better understood, the next question is about the relevance of current fabrication methods and composition of commercialized products: carbon blacks as well as PTFE, which make up most of the slurries, have increasingly proved a lack of reliability due to corrosion problems and gradual loss of hydrophobicity during fuel cell operation. Alternative structures are therefore being considered involving carbon nanofibers or nanotubes to replace both components as single self-standing or in situ-grown layers.
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Mechanism of liquid water extraction in PEMFC
March 2011
How is liquid water generated at the cathode removed during normal fuel cell operation? After my September’s science note about the beneficial role of the microporous layer in low temperature fuel cell’s water management, additional highlights will expand the subject to all porous components adjacent to the membrane. The catalyst layer and the gas diffusion layer – with or without a microporous layer – strongly interact with water in both liquid and vapor form and contribute to mass transport losses in different ways, especially on the cathode side.
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March 2011
How is liquid water generated at the cathode removed during normal fuel cell operation? After my September’s science note about the beneficial role of the microporous layer in low temperature fuel cell’s water management, additional highlights will expand the subject to all porous components adjacent to the membrane. The catalyst layer and the gas diffusion layer – with or without a microporous layer – strongly interact with water in both liquid and vapor form and contribute to mass transport losses in different ways, especially on the cathode side.
Read more
Mechanism of microporous layer for PEMFC explained
September 2010
The microporous layer (MPL) treatment has long been proved beneficial to low-temperature fuel cell performances, particularly at high current and/or humidity conditions. But despite the general agreement on the existence of these benefits, the actual function of the MPL – besides creating better electrical and thermal contact between the catalyst layer and the gas diffusion media – was still fairly “misty”. Recent experimental and simulation studies have ultimately resulted in a single explanation involving control by the MPL of the number and size of liquid water droplets to be directed toward the GDL.
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September 2010
The microporous layer (MPL) treatment has long been proved beneficial to low-temperature fuel cell performances, particularly at high current and/or humidity conditions. But despite the general agreement on the existence of these benefits, the actual function of the MPL – besides creating better electrical and thermal contact between the catalyst layer and the gas diffusion media – was still fairly “misty”. Recent experimental and simulation studies have ultimately resulted in a single explanation involving control by the MPL of the number and size of liquid water droplets to be directed toward the GDL.
Read more
Carbon foam for mitigating water management issues in low temperature fuel cells
May 2010
Two original papers have recently proposed to deal with the water management problem by replacing by or adding to the conventional channeled bipolar plate of the PEM fuel cell, a novel material in this research area: porous carbon foam.
Metallic foams have been under consideration for batteries and other electrochemical devices, but in the fuel cell area the use of porous foam is clearly not a serious option yet. This could change thanks to the new results reported here .
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May 2010
Two original papers have recently proposed to deal with the water management problem by replacing by or adding to the conventional channeled bipolar plate of the PEM fuel cell, a novel material in this research area: porous carbon foam.
Metallic foams have been under consideration for batteries and other electrochemical devices, but in the fuel cell area the use of porous foam is clearly not a serious option yet. This could change thanks to the new results reported here .
Read more
A metal oxide alternative to carbon as catalyst support in low-temperature fuel cells
January 2010
Current commercial Pt/C catalysts suffer from a lack of durability in polymer electrolyte fuel cells (PEMFCs and DMFCs) due mainly to concomitant carbon corrosion and platinum dissolution/sintering during start-up and shut-down procedures. Metal oxides have been regarded as potential alternatives to high-surface area carbon for a while now, and in particular TiO2 thanks to its very good mechanical properties and superior electrochemical resistance in acidic and oxidative conditions. Two recent studies report significant milestones achieved toward the use of titanium dioxide in fuel cells: drastic increase of anode efficiency in DMFCs and enhanced stability of PEM fuel cell performances.
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January 2010
Current commercial Pt/C catalysts suffer from a lack of durability in polymer electrolyte fuel cells (PEMFCs and DMFCs) due mainly to concomitant carbon corrosion and platinum dissolution/sintering during start-up and shut-down procedures. Metal oxides have been regarded as potential alternatives to high-surface area carbon for a while now, and in particular TiO2 thanks to its very good mechanical properties and superior electrochemical resistance in acidic and oxidative conditions. Two recent studies report significant milestones achieved toward the use of titanium dioxide in fuel cells: drastic increase of anode efficiency in DMFCs and enhanced stability of PEM fuel cell performances.
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Iron to replace platinum in PEM fuel cells anytime soon?
Septembre 2009
For our monthly scientific highlight, honor is given to the great results obtained by Pr Dodelet ‘s team at INRS, Canada, which have been published earlier this year in Science magazine. Their research focus is on non precious metal catalysts (NPMC) for the oxygen reduction reaction (ORR) in PEM fuel cells. The team has successfully prepared and tested Fe-N based compounds with a dramatically higher volumetric density of active sites towards ORR in the microporous carbon support. The best new catalyst exhibits an overall rate of reaction that is 35 times higher than the previous best NPMC as far and very close to the 2010 DoE target, and compares well with Pt-based catalysts at low current densities.
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Septembre 2009
For our monthly scientific highlight, honor is given to the great results obtained by Pr Dodelet ‘s team at INRS, Canada, which have been published earlier this year in Science magazine. Their research focus is on non precious metal catalysts (NPMC) for the oxygen reduction reaction (ORR) in PEM fuel cells. The team has successfully prepared and tested Fe-N based compounds with a dramatically higher volumetric density of active sites towards ORR in the microporous carbon support. The best new catalyst exhibits an overall rate of reaction that is 35 times higher than the previous best NPMC as far and very close to the 2010 DoE target, and compares well with Pt-based catalysts at low current densities.
Read more
