Experimental study on the membrane electrode assembly of a proton exchange membrane fuel cell: effects of microporous layer, membrane thickness and gas diffusion layer hydrophobic treatment

2017 ◽  
Vol 224 ◽  
pp. 337-345 ◽  
Author(s):  
Rui B. Ferreira ◽  
D.S. Falcão ◽  
V.B. Oliveira ◽  
A.M.F.R. Pinto
2012 ◽  
Vol 5 (1) ◽  
pp. 28-38 ◽  
Author(s):  
Tzyy-Lung Leon Yu ◽  
Hsiu-Li Lin ◽  
Po-Hao Su ◽  
Guan-Wen Wang

In this paper, we modify the conventional 5-layer membrane electrode assembly (MEA, in which a proton exchange membrane (PEM) is located at its center, two Pt-C-40 (Pt on carbon powder support, Pt content 40 wt.%) catalyst layers (CLs) are located on the surfaces of the both sides of the PEM and two gas diffusion layers (GDLs) are attached next on the outer surfaces of two Pt-C-40 layers) and propose 7-layer and 9-layer MEAs by coating thin Pt-black CLs at the interfaces between the Pt-C-40 layer and the GDL and between the PEM and the Pt-C-40 layer and reducing the Pt-C-40 loading. The reduced Pt loading quantity of the Pt-C-40 layer is equal to the increased Pt loading quantity of the Pt-black layer, thus the total amount of Pt loadings in the unmodified conventional MEA and the modified MEAs are at a fixed Pt loading quantity. These modified MEAs may complicate the manufacture process. The main advantage of these 7- and 9-layer MEAs is the thinner CL thickness and thus lower CL proton transport resistance. Because of the thin Pt-black layer thickness in MEA, we avoid agglomeration of the Pt-black particles and maintain high Pt catalytic activity. We show these new CL structure MEAs have better fuel cells performance than the conventional 5-layer MEA.


Author(s):  
Jiankui Chen ◽  
Xi Jiang ◽  
Wei Tang ◽  
Liang Ma ◽  
Yiqun Li ◽  
...  

A membrane electrode assembly is the core component of a proton-exchange membrane fuel cell stack. It consists of multilayer structured membranes which are flexible, heterogeneous and have variable cross section. To improve the efficiency of membrane electrode assembly processing and manufacturing, a roll-to-roll system with gas diffusion layer is designed. By peeling the protective membrane and the upper and lower gas diffusion layers’ hot-pressing, proton-exchange membrane is manufactured into a five-layer catalyst-coated membrane. Then, the catalyst-coated membrane is manufactured into membrane electrode assembly by multilayer membrane breakpoint die-cutting and laying-off. The system integrates multiple key technologies, including roll-to-roll precise feeding, gas diffusion layer multi-degree accurate operation and multichannel temperature control, to realize the precise positioning of flexible multilayer membrane and brittle gas diffusion layer. The tension inhomogeneity and critical wrinkling tension are modeled for web traveling in the continuous roll-to-roll manufacturing equipment. The proposed roll-to-roll stack and lamination system effectively combines discontinuous hot-pressing, die-cutting, laying-off technics to realize the high-efficiency manufacturing of membrane electrode assembly.


Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6232
Author(s):  
Viorel Ionescu ◽  
Adriana Elena Balan ◽  
Alexandra Maria Isabel Trefilov ◽  
Ioan Stamatin

The microporous layer (MPL) constitutes a critical component of the gas diffusion layer within the membrane electrode assembly (MEA) of a proton exchange membrane fuel cell (PEM FC). The MPL plays a fundamental role in various processes during FC operation: control of membrane humidification, heat distribution throughout the MEA, excess water removal from the cathode, and transportation of fuel to the reaction sites. Previously, we investigated the performance of a fuel cell unit employing an MPL based on laser-induced graphene (LIG) produced by the laser pyrolysis of polymeric (polyimide) substrates. The prototype LIG-based unit was tested over the typical range of relative humidity and temperature conditions. The polarization curves observed in that study displayed broad ohmic loss regions and high stability along the concentration loss regions, an interesting electrical behavior that justified developing the present voltage-current density study for the same FC prototype compared to one bearing a commercial pyrolytic carbon black MPL. The same operating conditions as in the first study were applied, in order to properly compare the performance efficiencies between the two systems; these are evaluated by considering the thermodynamic losses influence on the exergy efficiency, to exceed any limitations inherent in the classical energy efficiency analysis.


Author(s):  
Britta Mayerhöfer ◽  
Konrad Ehelebe ◽  
Florian Dominik Speck ◽  
Markus Bierling ◽  
Johannes Bender ◽  
...  

Bipolar membrane|electrode interface water electrolyzers (BPEMWE) were found to outperform a proton exchange membrane (PEM) water electrolyzer reference in a similar membrane electrode assembly (MEA) design based on individual porous...


2018 ◽  
Vol 778 ◽  
pp. 275-282
Author(s):  
Noaman Khan ◽  
Saim Saher ◽  
Xuan Shi ◽  
Muhammad Noman ◽  
Mujahid Wasim Durani ◽  
...  

Highly porous ZIF-67 (Zeolitic imidazole framework) has a conductive crystalline metal organic framework (MOF) structure which was served as a precursor and template for the preparation of nitrogen-doped carbon nanotubes (NCNTs) electrocatalysts. As a first step, the chloroplatinic acid, a platinum (Pt) precursor was infiltrated in ZIF-67 with a precise amount to obtain 0.12 mg.cm-2 Pt loading. Later, the infiltrated structure was calcined at 700°C in Ar:H2 (90:10 vol%) gas mixture. Multi-walled nitrogen-doped carbon nanotubes were grown on the surface of ZIF-67 crystals following thermal activation at 700°C. The resulting PtCo-NCNTs electrocatalysts were deposited on Nafion-212 solid electrolyte membrane by spray technique to study the oxygen reduction reaction (ORR) in the presence of H2/O2 gases in a temperature range of 50-70°C. The present study elucidates the performance of nitrogen-doped carbon nanotubes ORR electrocatalysts derived from ZIF-67 and the effects of membrane electrode assembly (MEA) steaming on the performance of proton exchange membrane fuel cell (PEMFC) employing PtCo-NCNTs as ORR electrocatalysts. We observed that the peak power density at 70°C was 450 mW/cm2 for steamed membrane electrode assembly (MEA) compared to 392 mW/cm2 for an identical MEA without steaming.


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