638
Distributed PEFC Performance during Cationic Contamination

Tuesday, May 13, 2014: 17:00
Hamilton, Ground Level (Hilton Orlando Bonnet Creek)
M. A. Uddin (Center for Clean Energy Engineering, University of Connecticut, University of Connecticut), X. Wang (University of Connecticut, Department of Materials Science & Engineering, University of Connecticut), M. O. Ozdemir (University of Connecticut, Center for Clean Energy Engineering, University of Connecticut), J. Qi, L. J. Bonville (University of Connecticut), U. Pasaogullari, and T. Molter (Center for Clean Energy Engineering, University of Connecticut, University of Connecticut)
In our previous studies (1-3), severe performance degradation of PEFCs was observed due to cationic impurities. In this study, we investigate how cations affect the spatial performance distribution in a PEFC using a segmented cell.

The segmented cell hardware consists of an aluminum anode flow field, a segmented aluminum cathode flow field, two aluminum end plates and one cupper current collector. All the aluminum parts were gold plated. Cathode flow field was divided into eight segments. Eight pieces of equal size aluminum current collectors were placed inside a PTFE block and straight flow channels were machined through both the PTFE and the aluminum segments (Figure 1). Total active area of the cell was 5 cm2. 2.85 mM CaSO4solution was introduced in the air stream through a nebulizer (1-3) at a rate of 110 uL/min, corresponding to 21.2 ppm based on dry air flow rate.

Figure 2 shows the voltage and current density distribution profile in each segment. The cell was operated at a constant total current of 1 A. During the baseline test of 24 hours, pure air was injected through cathode. The current in each segment remained constant through this period. Following the baseline test, the contaminant was injected in the air stream. The segments closest to the gas inlet were first affected by the contaminant. The current density in the segments closest to the gas inlet decreased while the segments closest to the outlet increased. Since it was a constant current test, when the current in the segments closest to the gas inlet decrease, other segments picked up that current to maintain total current constant.

During the baseline test, voltage remained constant in all segments. After contaminant injection, the cell voltage started to decrease and after 50 hours, voltages in each segments fluctuated. The voltage fluctuation was found to be mainly due to mass transport loss. The contaminant solution evaporated and deposited on the flow field and the GDL surface (Figure 3), and entered into the GDL which caused the mass transport losses. Moreover, the aluminum flow fields corroded and corrosion byproducts also deposited on the flow field and GDL surface. Throughout the test, there was no significant variation in voltage between segments.

Acknowledgements

The authors gratefully acknowledge financial support from NSF (CBET-0748063), DOE-EERE through University of Hawaii-Hawaii Natural Energy Institute (DE-EE0000467).

References

1. X. Wang, J. Qi, M. O. Ozdemir, M. A. Uddin, L. Bonville, U. Pasaogullari, T. Molter, ECS Trans., 58 (1) 529-536 (2013)

2. J. Qi, X. Wang, M. O. Ozdemir, M. A. Uddin, L. Bonville, U. Pasaogullari, T. Molter, ECS Trans., 58 (1) 537-542 (2013).

3. M. A. Uddin, X. Wang, J. Qi, M. O. Ozdemir, L. Bonville, U. Pasaogullari, T. Molter, ECS Trans., 58 (1) 543-553 (2013).

See more of: Catalysts and Catalyst/Electrolyte Interfaces and Interphases II
See more of: F1: Characterization of Interfaces and Interphases
See more of: Fuel Cells, Electrolyzers, and Energy Conversion
<< Previous Abstract | Next Abstract