Membrane patterned by pulsed laser micromachining for proton exchange membrane fuel cell with sputtered ultra-low catalyst loadings

International audienceProton exchange membranes were nano-and micro-patterned on their cathode side by pressing them against stainless steel molds previously irradiated by a Ti:Sapphire femtosecond laser. The membranes were associated to ultra-low loaded thin catalytic layers (25 µgPt cm-2) prepared by plasma magnetron sputtering. The Pt catalyst was sputtered either on the membrane or on the porous electrode. The fuel cell performance in dry conditions were found to be highly dependent on the morphology of the membrane surface. When nanometric ripples covered by a Pt catalyst were introduced on the surface of the membrane, the fuel cell outperformed the conventional one with a flat membrane. By combining nano-and micro-patterns (nanometric ripples and 11-24 µm deep craters), the performance of the cells was clearly enhanced. The maximum power density achieved by the fuel cell was multiplied by a factor of 3.6 (at 50 °C and 3 bars): 438 mW cm-2 vs 122 mW cm-2. This improvement is due to high catalyst utilization with a high membrane conductivity. When Pt is sputtered on the porous electrode (and not on the membrane), the contribution of the patterned membrane to the fuel cell efficiency was less significant, except in the presence of nanometric ripples. This result suggests that the patterning of the membrane must be consistent with the way the catalyst is synthesized, on the membrane or on the porous electrode

Characterization of transport of neutral and ionized species in reactive HiPIMS process

International audienceThe aim of the studyis to developa software to control in real time the thin film deposition of a plasma magnetron process. The thin films will be obtained by HiPIMS plasma process (High Power Impulse Magnetron Sputtering)[1]. Nowadays, it is the only physical process able to ensure optimal compliance ofthe coatings on complex 3D substrates. It is also easy to implement on industrial production lines thatare already equipped by conventional magnetron sputtering systems. In order to well understand this HiPIMS process and to control it by software, we will use three plasma diagnostics:absorption spectroscopy, mass spectrometry and optical emission spectroscopy(OES). The combination of the diagnostics will allow studying the behaviourof ions and neutrals created in the plasma and their transport in the spatial post-discharge. These measurements will serve to establish abacuses for the control software. We will also associate OES data with the conformity and properties of the coatings to verify if the latter could be linked with some OES lines, whose evolutions could be the signature of the imposed modifications

Étude de l’interaction plasma-eau en régime de décharge nanoseconde en condition atmosphérique

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Study of the synthesis of nanoparticles in liquid phase enhanced by microsecond plasma discharges at atmospheric pressure

International audienc

Caractérisation du transport des espèces neutres et ionisées en procédé réactif HiPIMS par fluorescence induite par diode laser

International audienc

Functionalization and characterization study of MOFs by plasma process

International audienc

Characterization of transport of neutral and ionized species in reactive-HiPIMS process (R-HiPIMS)

International audienc