Comment diminuer la quantité de platine dans les piles à combustible ?

Poster (2012, May 20)

Beneficial effect of carbon nanotubes on the performances of Nafion membranes in fuel cell applications

in Journal of Membrane Science (2007), 303(1-2), 252-257

Multi-walled carbon nanotubes (MWCNTs) were dispersed by melt-extrusion within Nafion(R) membranes in order to decrease the methanol permeability without deleterious effect on the ionic conductivity. The ... [more ▼]

Multi-walled carbon nanotubes (MWCNTs) were dispersed by melt-extrusion within Nafion(R) membranes in order to decrease the methanol permeability without deleterious effect on the ionic conductivity. The risk of short-circuits was minimized by keeping the carbon nanotubes content lower than the percolation threshold. Two series of carbon nanotubes grafted by carboxylic acid groups were used, i.e., commercially available carbon nanotubes and MWCNTs home-grafted by carboxylic acid containing alkyl radicals. The second series of nanotubes were more resistant to break-up during melt-processing. Methanol permeability was decreased by approximately 60% without any decrease in the ionic conductivity. In parallel, the Young's modulus was increased by 140% and 160% as compared to pure Nafion(R) at MWCNT contents of 1 and 2 wt%, respectively. [less ▲]

Foams of polycaprolactone/MWNT nanocomposites for efficient EMI shielding

Conference (2007, August 27)

Contribution of nanoclays to the barrier properties of a model proton exchange membrane for fuel cell application

in Journal of Membrane Science (2006), 270(1-2), 50-56

Direct methanol fuel cells (DMFCs) that use a proton exchange membrane (PEM) as electrolyte, is a promising alternative source of energy for the future. However, methanol crossover from the anodic side to ... [more ▼]

Direct methanol fuel cells (DMFCs) that use a proton exchange membrane (PEM) as electrolyte, is a promising alternative source of energy for the future. However, methanol crossover from the anodic side to the cathodic one is a major problem in DMFC. Proper dispersion of layered silicates within the fuel cell membrane has been proposed as a strategy for improving the barrier properties of the membrane. The validity of this approach has been tested in case of a model membrane consisting of phosphotungstic acid doped poly(vinyl alcohol). A solvent casting technique has been used, which allows the nanofiller to be delaminated by an ultrasonic pre-treatment, as confirmed by TEM and XRD analysis. The layered silicates have a favourable impact on the methanol permeability, whose the decrease overcompensates some loss in ionic conductivity. [less ▲]

Nafion-layered silicate nanocomposite membrane for fuel cell application

in e-Polymers (2004), (18), 1-13

Direct methanol fuel cells (DMFCs) using a proton exchange membrane as electrolyte is an attractive option for electricity generation. The most widely used membrane in the DMFC system is based on a ... [more ▼]

Direct methanol fuel cells (DMFCs) using a proton exchange membrane as electrolyte is an attractive option for electricity generation. The most widely used membrane in the DMFC system is based on a perfluorinated polymer bearing sulfonic acid functions like Nafion®. The latter combines chemical, mechanical and thermal stability and high protonic conductivity but shows elevated methanol permeability. We propose the preparation of a novel type of hybrid membranes to tentatively solve this problem. This innovative material results from the homogeneous dispersion of a nano-scaled inorganic filler within Nafion. The filler consists of stacks of negatively charged alumino-silicate layers (Cloisite), with a positive counter-ion in the interlamellar space. The purpose of the addition of this filler is to decrease methanol diffusion through the polymer membrane without decreasing too much the ionic conductivity. [less ▲]