scholarly journals Influence of Ionomer Content in the Catalytic Layer of MEAs Based on Aquivion® Ionomer

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3832
Author(s):  
Irene Gatto ◽  
Ada Saccà ◽  
David Sebastián ◽  
Vincenzo Baglio ◽  
Antonino Salvatore Aricò ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Cell Performance ◽  
Membrane Electrode ◽  
Catalytic Layer ◽  
Fuel Cell Performance ◽  
Dispersing Agent ◽  
Electrode Assemblies ◽  
Electrolyte Membranes ◽  
Perfluorinated Sulfonic Acid ◽  
Catalyst Utilization

Perfluorinated sulfonic acid (PFSA) polymers such as Nafion® are widely used for both electrolyte membranes and ionomers in the catalytic layer of membrane-electrode assemblies (MEAs) because of their high protonic conductivity, σH, as well as chemical and thermal stability. The use of PFSA polymers with shorter side chains and lower equivalent weight (EW) than Nafion®, such as Aquivion® PFSA ionomers, is a valid approach to improve fuel cell performance and stability under drastic operative conditions such as those related to automotive applications. In this context, it is necessary to optimize the composition of the catalytic ink, according to the different ionomer characteristics. In this work, the influence of the ionomer amount in the catalytic layer was studied, considering the dispersing agent used to prepare the electrode (water or ethanol). Electrochemical studies were carried out in a single cell in the presence of H2-air, at intermediate temperatures (80–95 °C), low pressure, and reduced humidity (50% RH. %). The best fuel cell performance was found for 26 wt.% Aquivion® at the electrodes using ethanol for the ink preparation, associated to a maximum catalyst utilization.

Probing the influence of the gas diffusion layer on water retention in membrane electrode assemblies via electrochemical impedance spectroscopy

2018 ◽  
Author(s):  
Foroughazam Afsahi ◽  
E. Bradley Easton
Keyword(s):  
Fuel Cell ◽  
Electrochemical Impedance ◽  
Catalyst Layer ◽  
Pem Fuel Cell ◽  
Gas Diffusion ◽  
Cell Performance ◽  
Carbon Paper ◽  
Membrane Electrode ◽  
Fuel Cell Performance ◽  
Electrode Assemblies

The effect of the relative humidity (RH) of supplied gases on PEM fuel cell performance was monitored by electrochemical impedance spectroscopy (EIS). Two different Nafion®-based membrane electrode assemblies (MEAs) were prepared from two commercially available gas diffusion layers (GDLs) based on carbon paper and carbon cloth. By performing EIS measurements under condition where the transmission line model was applicable, both the ionic resistance in catalyst layer (RΣ) and the membrane resistance (Rmem) could be probed. The extent of this impact, however, depends on the GDL substrate properties and the electrode side to which the dry gas was fed. Overall, the carbon paper based MEA provided better fuel cell performance when the dry gas condition was applied, whereas the cloth based MEA revealed better fuel cell performance with fully saturated reactant gases. Moreover, the later one demonstrates a better capability to address the flooding issue at high current density even when symmetric dry gas arrangement (both dry fuel and oxidant gases) was studied. Variation of fuel gas RH at the anode perturb the fuel cell performance less strongly compared with the other arrangements. This implies that with the fully hydrated cathode gas water transport via back diffusion from the cathode to the anode could maintain the hydrated membrane and catalyst layer to some extent. By using this EIS methodology, the interplay of GDL properties and reactant gases RH on PEM fuel cell performance can be more clearly understood.

Nafion/PBI Nanofiber Composite Membranes for Fuel Cells Applications

2010 ◽  
Author(s):  
Tzyy-Lung Leon Yu ◽  
Shih-Hao Liu ◽  
Hsiu-Li Lin ◽  
Po-Hao Su
Keyword(s):  
Thin Film ◽  
Fuel Cell ◽  
Composite Membrane ◽  
Fiber Composite ◽  
Composite Membranes ◽  
Cell Performance ◽  
Membrane Electrode ◽  
Membrane Thickness ◽  
Fuel Cell Performance ◽  
Nano Fiber

The PBI (poly(benzimidazole)) nano-fiber thin film with thickness of 18–30 μm is prepared by electro-spinning from a 20 wt% PBI/DMAc (N, N′-dimethyl acetamide) solution. The PBI nano-fiber thin film is then treated with a glutaraldehyde liquid for 24h at room temperature to proceed chemical crosslink reaction. The crosslink PBI nano-fiber thin film is then immersed in Nafion solutions to prepare Nafion/PBI nano-fiber composite membranes (thickness 22–34 μm). The morphology of the composite membranes is observed using a scanning electron microscope (SEM). The mechanical properties, conductivity, and unit fuel cell performance of membrane electrode assembly (MEA) of the composite membrane are investigated and compared with those of Nafion-212 membrane (thickness ∼50 μm) and Nafion/porous PTFE (poly(tetrafluoro ethylene)) composite membrane (thickness ∼22 μm). We show the present composite membrane has a similar fuel cell performance to Nafion/PTFE and a better fuel cell performance than Du Pont Nafion-212.

The effect of water uptake gradient in membrane electrode assembly on fuel cell performance

2011 ◽  
Vol 80 (2) ◽  
pp. 201-206 ◽  
Author(s):  
H. Fujita ◽  
F. Shiraki ◽  
Y. Oshima ◽  
T. Tatsumi ◽  
T. Yoshikawa ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Water Uptake ◽  
Membrane Electrode Assembly ◽  
Cell Performance ◽  
Membrane Electrode ◽  
Fuel Cell Performance ◽  
Effect Of Water

Conductive area ratio of multiblock copolymer electrolyte membranes evaluated by e-AFM and its impact on fuel cell performance

2009 ◽  
Vol 194 (2) ◽  
pp. 662-667 ◽  
Author(s):  
Naohiko Takimoto ◽  
Shogo Takamuku ◽  
Mitsutaka Abe ◽  
Akihiro Ohira ◽  
Hae-Seung Lee ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Area Ratio ◽  
Cell Performance ◽  
Fuel Cell Performance ◽  
Multiblock Copolymer ◽  
Electrolyte Membranes ◽  
Copolymer Electrolyte

Enhancement of PEM Fuel Cell Performance by Flow Control

2014 ◽  
Vol 804 ◽  
pp. 75-78 ◽  
Author(s):  
Vinh Nguyen Duy ◽  
Jung Koo Lee ◽  
Ki Won Park ◽  
Hyung Man Kim
Keyword(s):  
Fuel Cell ◽  
Flow Field ◽  
Pem Fuel Cell ◽  
Membrane Electrode Assembly ◽  
Cell Performance ◽  
Field Pattern ◽  
Battery Life ◽  
Membrane Electrode ◽  
Fuel Cell Performance ◽  
Serpentine Flow Field

Flow-field design affects directly to the PEM fuel cell performance. This study aims to stimulate the under-rib convection by adding sub-channels and by-passes to the conventional-advanced serpentine flow-field to improve the PEM fuel cell performance. The experimental results show that if reacting gases flow in the same direction as the neighboring main channels, the under-rib convection shows a flow from the main channels to the sub-channels makes progress in reducing pressure drop and enhancing uniform gas supply and water diffusion. Alternatively, if in the direction opposite to that of the neighboring main channels, the under-rib convection shows a flow from the inlet side towards the outlet side across the sub-channel as in the conventional serpentine channels. Analyses of the local transport phenomena in the cell suggest that the inlet by-pass supplies the reacting gases uniformly from the entrance into the sub-channels and the outlet by-pass enhances water removal. Novel serpentine flow-field pattern employing sub-channels and by-passes shows uniform current density and temperature distribution by uniformly supplying the reacting gas. Furthermore, performance improvement of around 20% is observed from the experimental performance evaluation. As a result, longer battery life is expected by reducing the mechanical stress of membrane electrode assembly.

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