Experimental Investigation of Irreversibility of a Proton Exchange Membrane Fuel Cell

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
I. Khazaee

For an 11 W proton exchange membrane (PEM) fuel cell, the exergy analysis at different channel geometry and internal parameters such as temperature, pressure, and mass flow rate are investigated experimentally. The geometry of the cell is rectangular, elliptical, and triangular. A PEM fuel cell with 25cm2 active area and Nafion 117 membrane with 4 mg Pt cm-2 for the anode and cathode is employed as a membrane electrode assembly. The results show that when the geometry of the cell is rectangular, the irreversibility of the cell is at lower value and the exergy efficiency is at higher value. Also, the results show that with the increase of hydrogen, oxygen, and cell temperature, the exergy efficiencies of the cell increase and irreversibilities decrease.

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.


Energy ◽  
2007 ◽  
Vol 32 (12) ◽  
pp. 2401-2411 ◽  
Author(s):  
Apichai Therdthianwong ◽  
Phochan Manomayidthikarn ◽  
Supaporn Therdthianwong

Author(s):  
Attila Husar ◽  
Andrew Higier ◽  
Hongtan Liu

Water management is of critical importance in a proton exchange membrane (PEM) fuel cell. Yet there are very limited studies of water transfer through the membrane and no data are available for water transfer due to individual mechanisms through the membrane electrode assembly (MEA) in an operational fuel cell. Thus it is the objective of this study to measure water transfer through the MEA due to different mechanisms through the membrane electrode assembly (MEA) of an operational PEM fuel cell. The three different mechanisms of water transfer, i.e., electro-osmotic drag, diffusion and hydraulic permeation were isolated by specially imposed boundary conditions. Therefore water transfer through the MEA due to each mechanism could be measured separately. In this study, all the data were collected in an actual assembled operational fuel cell, and some of the data were collected while the fuel cell was generating power. The measured results showed that water transfer due to hydraulic permeation, i.e. the pressure difference between the anode and cathode is at least an order of magnitude lower than those due to other two mechanisms. The data for water transfers due to electro-osmosis and diffusion through the MEA are in good agreement with some of the data and model predications in the literature for the membrane. The methodology used in this study is simple and can be easily adopted for in-situ water transfer measurement due to different mechanisms in actual PEM fuel cells without any cell modifications.


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