Effect of Electrode Surface Area Distribution on High Current Density Performance of PEM Fuel Cells

2011 ◽  
Vol 159 (1) ◽  
pp. B53-B66 ◽  
Author(s):  
Mark K. Debe
Keyword(s):  
Fuel Cells ◽  
Surface Area ◽  
Current Density ◽  
Electrode Surface ◽  
High Current Density ◽  
Pem Fuel Cells ◽  
High Current ◽  
Area Distribution

Separate Measurement of Current Density Under the Channel and the Shoulder in PEM Fuel Cells

2007 ◽  
Author(s):  
Lin Wang ◽  
Hongtan Liu
Keyword(s):  
Fuel Cells ◽  
Diffusion Layer ◽  
Current Density ◽  
Electrical Resistance ◽  
High Current Density ◽  
Gas Diffusion Layer ◽  
Pem Fuel Cells ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Experimental Results

In a proton exchange membrane (PEM) fuel cell current density under the shoulder can be very different from that under the gas channel and the knowledge of where the current density is higher is critical in flow field designs in order to optimize cell performance. Yet, up to date this issue has not been resolved. In this study, a novel yet simple approach was adopted to directly measure the current densities under the channel and the shoulder in PEM fuel cells separately. In this approach, the cathode catalyst layer was so designed that either the area under the shoulder or the area under the channel was loaded with catalyst. Such a design guaranteed the currents generated under the shoulder and the channel could be measured separately. Experimental results showed that the current density produced under the channel was lower than that under the shoulder except in the high current density region. To determine whether the lateral electrical resistance of the gas diffusion layer (GDL) was the causes for lower current density under the channel, an additional set of experiments were conducted. In this set of experiments, a silver mesh was added on the top of the gas diffusion layer (GDL) and the experimental results showed that GDL lateral electrical resistance was not the cause and it had a negligible effect on lateral current density distribution.

scholarly journals Ultrathin Electrolyte Membranes with PFSA-Vinylon Intermediate Layers for PEM Fuel Cells

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1730
Author(s):  
Jedeok KIM ◽  
Kazuya Yamasaki ◽  
Hitoshi Ishimoto ◽  
Yusuke Takata
Keyword(s):  
Fuel Cells ◽  
Polyvinyl Alcohol ◽  
High Current Density ◽  
Pem Fuel Cells ◽  
High Humidity ◽  
High Current ◽  
Intermediate Layers ◽  
Current Voltage ◽  
Electrolyte Membranes ◽  
Reinforcing Material

We prepared ultrathin PFSA/PFSA-vinylon/PFSA laminated electrolyte membranes (thickness = 10 μm) for fuel cells without using a reinforcing material. Nafion and Aquivion solutions were used as PFSA polymers. Vinylon was synthesized by formalizing polyvinyl alcohol. From the current-voltage measurements using ultrathin PFSA/PFSA-vinylon/PFSA membranes; the cell resistances are significantly lower than that using a 50 μm Nafion membrane. A high current density was obtained under both low- and high-humidity conditions. Ultrathin PFSA/PFSA-vinylon/PFSA laminated membranes will help to further improve the performance of PEMFCs.

The Nature of Flooding and Drying in Polymer Electrolyte Fuel Cells

2005 ◽  
Author(s):  
P. A. Chuang ◽  
A. Turhan ◽  
A. K. Heller ◽  
J. S. Brenizer ◽  
T. A. Trabold ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Current Density ◽  
Liquid Water ◽  
High Current Density ◽  
Liquid Water Content ◽  
Small Mass ◽  
Neutron Imaging ◽  
Small Range ◽  
High Current ◽  
Voltage Loss

Two different 50 cm2 fuel cells operated at high current density (1.3A/cm2–1.5A/cm2) were visualized using neutron imaging, and the liquid water content in the flow channels and diffusion media under the lands and channels was calculated and compared. At high current density with fully humidified inlet flow, a direct comparison between flooded and non-flooded conditions was achieved by increasing the fuel cell temperature over a small range, until voltage loss from flooding was alleviated. Results indicate that a surprisingly small mass of liquid water is responsible for a significant voltage loss. The deleterious effects of flooding are therefore more easily explained with a locally segregated flooded pore model, rather than a homogeneously flooded pore and blockage phenomenon. Anode dryout was similarly observed and quantified, and results indicate that an exceedingly small mass of water is responsible for significant voltage loss, which is consistent with expectations. The results presented help to form a more complete vision of the flooding loss and anode dryout phenomena in PEFCs.

scholarly journals Optimization of 3D ZnO brush-like nanorods for dye-sensitized solar cells

RSC Advances ◽  
2018 ◽  
Vol 8 (18) ◽  
pp. 9775-9782 ◽  
Author(s):  
Simona Pace ◽  
Alessandro Resmini ◽  
Ilenia G. Tredici ◽  
Alessandro Soffientini ◽  
Xuan Li ◽  
...  
Keyword(s):  
Solar Cells ◽  
Surface Area ◽  
Current Density ◽  
High Current Density ◽  
Dye Sensitized Solar Cells ◽  
Large Surface Area ◽  
High Current ◽  
Dye Sensitized ◽  
Sensitized Solar Cells

Optimized 3D ZnO brush-like nanorods showing large surface area are presented as the photoanode in enhanced high-current-density DSSCs.

Galvanostatic dissolution of mercury from the surface of glassy carbon into thiocyanate solution

1980 ◽  
Vol 45 (1) ◽  
pp. 169-178 ◽  
Author(s):  
František Opekar ◽  
Karel Holub
Keyword(s):  
Glassy Carbon ◽  
Electrode Surface ◽  
High Current Density ◽  
High Current ◽  
Nernst Equation ◽  
Potential Oscillations ◽  
Thiocyanate Solution ◽  
Theoretical Assumptions ◽  
Solution Proceeds ◽  
Dissolution Current

The galvanostatic dissolution of mercury from the surface of glassy carbon into a thiocyanate solution proceeds in accord with theoretical assumptions, as manifested by the constant product of the dissolution current and transition time. Under certain relations between the amount of oxidised mercury and concentration of thiocyanate at the electrode surface, however, a small part of the mercury dissolves at more positive potentials than correspond to the Nernst equation. This dissolution can be accompanied by potential oscillations. The anomalous behaviour is elucidated by the concept about coverage of a certain part of mercury with a film of sparingly soluble compounds of SCN- ions with mercury. This film is formed at the end of the galvanostatic dissolution on certain places of the electrode surface covered with mercury droplets, where SCN- ions are much exhausted as a result of a high current density.

Sign in / Sign up

Export Citation Format

Share Document