Plasma-Polymerized Proton-Conducting Membranes for Reducing Methanol Permeation in DMFCs

2005 ◽  
Vol 2 (3) ◽  
pp. 186-189 ◽  
Author(s):  
D. Gruber ◽  
N. Ponath ◽  
J. Müller
Keyword(s):  
Gas Diffusion ◽  
Polymerization Process ◽  
Methanol Permeability ◽  
Gas Diffusion Layers ◽  
Proton Conducting ◽  
Diffusion Layers ◽  
Deposition Parameters ◽  
Electrolyte Membranes ◽  
Conducting Membranes ◽  
Methanol Permeation

A plasma polymerization process for preparing proton-conducting electrolyte membranes from tetrafluoroethylene and water is presented. They can be deposited on different substrates, e.g., gas diffusion layers or as barrier layers on other polymer electrolyte membranes. An advantage of the plasma-polymerized membranes is their lower methanol permeability due to their highly cross-linked structure. Methanol permeation measurements with 3M methanol solution exhibit methanol permeabilities which are by an order of a magnitude less than for Nafion® 115. The proton conductivity of the plasma-polymerized membranes varies from 10to160mS∕cm depending on deposition parameters.

scholarly journals Pulsed Electrodeposition of Tin Electrocatalysts onto Gas Diffusion Layers for Carbon Dioxide Reduction to Formate

MRS Advances ◽  
2016 ◽  
Vol 2 (8) ◽  
pp. 451-458 ◽  
Author(s):  
Sujat Sen ◽  
Brian Skinn ◽  
Tim Hall ◽  
Maria Inman ◽  
E. Jennings Taylor ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Catalyst Particle ◽  
Gas Diffusion ◽  
Gas Diffusion Layers ◽  
Electrochemical Conversion ◽  
Diffusion Layers ◽  
Pulse Electroplating ◽  
Catalyst Particle Size ◽  
Deposition Parameters ◽  
Current Densities

ABSTRACTThis paper discusses a pulse electroplating method for developing tin (Sn)-decorated gas diffusion electrodes (GDEs) for the electrochemical conversion of carbon dioxide (CO2) to formate. The pulse-plated Sn electrodes achieved current densities up to 388 mA/cm2, more than two-fold greater than conventionally prepared electrodes (150 mA/cm2), both at a formate selectivity of 80%. Optical and microscopic analyses indicate improvements in deposition parameters could further enhance performance by reducing the catalyst particle size.

Stack Compression of PEM Fuel Cells

2004 ◽  
Author(s):  
Yeh-Hung Lai ◽  
Daniel P. Miller ◽  
Chunxin Ji ◽  
Thomas A. Trabold
Keyword(s):  
Fuel Cell ◽  
Membrane Electrode Assembly ◽  
Pem Fuel Cells ◽  
Gas Diffusion ◽  
Membrane Electrode ◽  
Gas Diffusion Layers ◽  
Dimensional Changes ◽  
Diffusion Layers ◽  
Wide Range ◽  
Electrolyte Membranes

The effect of dimensional changes of fuel cell components from temperature and hydration cycles on the stack compression is investigated in this paper. Using a simple spring model including the membrane electrode assembly (MEA), gas diffusion layers (GDL), bipolar plates, seal gaskets, current collectors, insulation plates, end plates, and side plates, we find significant compression changes from 30% over-compression to 23% compression loss from both temperature and humidity changes. The wide range of variation in stack compression is attributed to the swelling behavior of polymer electrolyte membranes, the compression behavior of gas diffusion layers, and the design of stack assembly. This paper also reports the use of finite element method to investigate the compression of MEA and GDL over the channel area where MEA buckling from membrane swelling can result in separation of MEA and GDL. It is suggested that the compression over channels can be improved with higher transverse shear modulus in the GDL in addition to the use of narrower channels. In this paper, we will also discuss the challenges facing the fuel cell manufacturers and component suppliers on the needs for new materials with improved mechanical properties and better testing/modeling techniques to help achieving stable compression and better fuel cell stack designs.

Imaging of desaturation of the frozen gas diffusion layers by synchrotron X-ray radiography

2021 ◽  
Author(s):  
Yuzhou Zhang ◽  
Viral Hirpara ◽  
Virat Patel ◽  
Chen Li ◽  
Ryan Anderson ◽  
...  
Keyword(s):  
Gas Diffusion ◽  
Gas Diffusion Layers ◽  
X Ray ◽  
Diffusion Layers

scholarly journals Mass Transport Limitations of Water Evaporation in Polymer Electrolyte Fuel Cell Gas Diffusion Layers

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2967
Author(s):  
Adrian Mularczyk ◽  
Andreas Michalski ◽  
Michael Striednig ◽  
Robert Herrendörfer ◽  
Thomas J. Schmidt ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Liquid Water ◽  
Evaporative Cooling ◽  
Gas Diffusion ◽  
Polymer Electrolyte Fuel Cell ◽  
Ex Situ ◽  
Water Evaporation ◽  
Evaporative Water ◽  
Gas Diffusion Layers ◽  
Diffusion Layers

Facilitating the proper handling of water is one of the main challenges to overcome when trying to improve fuel cell performance. Specifically, enhanced removal of liquid water from the porous gas diffusion layers (GDLs) holds a lot of potential, but has proven to be non-trivial. A main contributor to this removal process is the gaseous transport of water following evaporation inside the GDL or catalyst layer domain. Vapor transport is desired over liquid removal, as the liquid water takes up pore space otherwise available for reactant gas supply to the catalytically active sites and opens up the possibility to remove the waste heat of the cell by evaporative cooling concepts. To better understand evaporative water removal from fuel cells and facilitate the evaporative cooling concept developed at the Paul Scherrer Institute, the effect of gas speed (0.5–10 m/s), temperature (30–60 °C), and evaporation domain (0.8–10 mm) on the evaporation rate of water from a GDL (TGP-H-120, 10 wt% PTFE) has been investigated using an ex situ approach, combined with X-ray tomographic microscopy. An along-the-channel model showed good agreement with the measured values and was used to extrapolate the differential approach to larger domains and to investigate parameter variations that were not covered experimentally.

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