scholarly journals Spectrophotometric Analysis of Phosphoric Acid Leakage in High-Temperature Phosphoric Acid-Doped Polybenzimidazole Membrane Fuel Cell Application

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Seungyoon Han ◽  
Yeon Hun Jeong ◽  
Ju Hae Jung ◽  
Alina Begley ◽  
Euiji Choi ◽  
...  

High-temperature proton exchange membrane fuel cells (HT-PEMFCs) utilize a phosphoric acid- (PA-) doped polybenzimidazole (PBI) membrane as a polymer electrolyte. The PA concentration in the membrane can affect fuel cell performance, as a significant amount of PA can leak from the membrane electrode assembly (MEA) by dissolution in discharged water, which is a byproduct of cell operation. Spectrophotometric analysis of PA leakage in PA-doped polybenzimidazole membrane fuel cells is described here. This spectrophotometric analysis is based on measurement of absorption of an ion pair formed by phosphomolybdic anions and the cationoid color reagent. Different color reagents were tested based on PA detection sensitivity, stability of the formed color, and accuracy with respect to the amount of PA measured. This method allows for nondestructive analysis and monitoring of PA leakage during HT-PEMFCs operation.

2019 ◽  
Author(s):  
Valentina Guccini ◽  
Annika Carlson ◽  
Shun Yu ◽  
Göran Lindbergh ◽  
Rakel Wreland Lindström ◽  
...  

The performance of thin carboxylated cellulose nanofiber-based (CNF) membranes as proton exchange membranes in fuel cells has been measured in-situ as a function of CNF surface charge density (600 and 1550 µmol g<sup>-1</sup>), counterion (H<sup>+</sup>or Na<sup>+</sup>), membrane thickness and fuel cell relative humidity (RH 55 to 95 %). The structural evolution of the membranes as a function of RH as measured by Small Angle X-ray scattering shows that water channels are formed only above 75 % RH. The amount of absorbed water was shown to depend on the membrane surface charge and counter ions (Na<sup>+</sup>or H<sup>+</sup>). The high affinity of CNF for water and the high aspect ratio of the nanofibers, together with a well-defined and homogenous membrane structure, ensures a proton conductivity exceeding 1 mS cm<sup>-1</sup>at 30 °C between 65 and 95 % RH. This is two orders of magnitude larger than previously reported values for cellulose materials and only one order of magnitude lower than Nafion 212. Moreover, the CNF membranes are characterized by a lower hydrogen crossover than Nafion, despite being ≈ 30 % thinner. Thanks to their environmental compatibility and promising fuel cell performance the CNF membranes should be considered for new generation proton exchange membrane fuel cells.<br>


2015 ◽  
Vol 3 (16) ◽  
pp. 8847-8854 ◽  
Author(s):  
Zhibin Guo ◽  
Ruijie Xiu ◽  
Shanfu Lu ◽  
Xin Xu ◽  
Shichun Yang ◽  
...  

A novel submicro-pore containing proton exchange membrane is designed and fabricated for application in high-temperature fuel cells.


1999 ◽  
Vol 575 ◽  
Author(s):  
T. Jan Hwang ◽  
Hong Shao ◽  
Neville Richards ◽  
Jerome Schmitt ◽  
Andrew Hunt ◽  
...  

ABSTRACTThe objective of this research is to develop the combustion chemical vapor deposition (CCVD) process for low-cost manufacture of catalytic coatings for proton exchange membrane fuel cell (PEMFC) applications. The platinum coatings as well as the fabrication process for membrane-electrode-assemblies (MEAs) were evaluated in a single testing fuel cell using hydrogen/oxygen. It was found that increasing the platinum loading from 0.05 to 0.1 mg/cm2 did not increase the fuel cell performance. The in-house MEA fabrication process needs to be improved to reduce the cell resistance. Significantly higher performance of Pt coating by the CCVD process has been obtained by MCT's fuelcell industry collaborators who are more experienced with MEA fabrication. The results can not be revealed due to confidentiality agreements.


Author(s):  
Torsten Berning

Abstract A numerical analysis of an air-cooled proton exchange membrane fuel cell (PEMFC) has been conducted. The model utilizes the Eulerian multi-phase approach to predict the occurrence and transport of liquid water inside the cell. It is assumed that all the waste heat must be carried out of the fuel cell with the excess air which leads to a strong temperature increase of the air stream. The results suggest that the performance of these fuel cells is limited by membrane overheating which is ultimately caused by the limited heat transfer to the laminar air stream. A proposed remedy is the placement of a turbulence grid before such a fuel cell stack to enhance the heat transfer and increase the fuel cell performance.


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