Use of FTIR to Analyze Ex-Situ and In-Situ Degradation of Perfluorinated Fuel Cell Ionomers

2019 ◽  
Vol 11 (1) ◽  
pp. 1093-1104 ◽  
Author(s):  
William E. Delaney ◽  
Wen Liu
Keyword(s):  
Fuel Cell ◽  
Ex Situ ◽  
In Situ Degradation

In-Situ and Ex-Situ Investigation of Lateral Current Density Variations in a PEM Fuel Cell With Serpentine Flow Field

2009 ◽  
Author(s):  
Andrew Higier ◽  
Hongtan Liu
Keyword(s):  
Fuel Cell ◽  
Flow Field ◽  
Contact Resistance ◽  
Current Density ◽  
Pem Fuel Cell ◽  
Gas Diffusion ◽  
Operating Conditions ◽  
Ex Situ ◽  
Serpentine Flow Field

One of the most common types of flow field designs used in proton exchange membrane (PEM) fuel cell is the serpentine flow field. It is used for its simplicity of design, its effectiveness in distributing reactants and its water removal capabilities. The knowledge about where current density is higher, under the land or the channel, is critical for flow field design and optimization. Yet, no direct measurement data are available for serpentine flow fields. In this study a fuel cell with a single channel serpentine flow field is used to separately measure the current density under the land and channel on the cathode. In this manner, a systematic study is conducted under a wide variety of conditions and a series of comparisons are made between land and channel current density. Results show that under most operating conditions, current density is higher under the land than that under the channel. However, at low voltage, a rapid drop off in current density occurs under the land due to concentration losses. In order to investigate the cause of the variations of current density under the land and channel and series of ex-situ and in-situ experiments were conducted. In the ex-situ portion of the study, the contact resistance between the gas diffusion electrode (GDE) and the graphite flow plate were measured using an ex-situ impedance spectroscopy technique. The values of the contact resistance under the channel were found to be larger than that under the land. This implies that the contact resistance under the land and channel vary greatly, likely due to variations in compression under different section of the flow field. These variations in turn cause current density variations under the land and channel.

Observation of Fuel Cell Membrane Degradation by Ex Situ and In Situ Electron Paramagnetic Resonance

2008 ◽  
Vol 155 (6) ◽  
pp. B570 ◽  
Author(s):  
B. Vogel ◽  
E. Aleksandrova ◽  
S. Mitov ◽  
M. Krafft ◽  
A. Dreizler ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Fuel Cell ◽  
Cell Membrane ◽  
Ex Situ ◽  
Membrane Degradation ◽  
Paramagnetic Resonance ◽  
Electron Paramagnetic

scholarly journals In Situ Electrochemical Characterization of a Microbial Fuel Cell Biocathode Running on Wastewater

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 839
Author(s):  
Sudarsu V. Ramanaiah ◽  
Cristina M. Cordas ◽  
Sara Matias ◽  
Luís P. Fonseca
Keyword(s):  
Cyclic Voltammetry ◽  
Fuel Cell ◽  
Microbial Fuel Cell ◽  
Microbial Fuel Cells ◽  
Ex Situ ◽  
Redox Processes ◽  
Electrode Surfaces ◽  
Fuel Cell Cathode

The electrochemical features of microbial fuel cells’ biocathodes, running on wastewater, were evaluated by cyclic voltammetry. Ex situ and in situ electrochemical assays were performed and the redox processes associated with the presence of microorganisms and/or biofilms were attained. Different controls using sterile media (abiotic cathode microbial fuel cell) and membranes covering the electrodes were performed to evaluate the source of the electrochemistry response (surface biofilms vs. biotic electrolyte). The bacteria presence, in particular when biofilms are allowed to develop, was related with the enhanced active redox processes associated with an improved catalytic activity, namely for oxygen reduction, when compared with the results attained for an abiotic microbial fuel cell cathode. The microbial main composition was also attained and is in agreement with other reported studies. The current study aims contributing to the establishment of the advantages of using biocathodes rather than abiotic, whose conditions are frequently harder to control and to contribute to a better understanding of the bioelectrochemical processes occurring on the biotic chambers and the electrode surfaces.

Sign in / Sign up

Export Citation Format

Share Document