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AC Impedance Spectroscopy Analysis of Improved Proton Exchange Membrane Fuel Cell Performance via Direct Inlet Humidity Control

Tan, Li
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1282322171

Abstract Details

2010, MS, University of Cincinnati, Engineering and Applied Science: Chemical Engineering.
Direct measurement of inlet gas relative humidity is used in conjunction with AC impedance spectroscopy to characterize PEM fuel cell performance when pervaporation is used. Pervaporation is the most efficient method of humidifying inlet gases for commercial automotive applications. However, this work demonstrates that improper sizing of a pervaporation unit for the expected range of conditions can cause significant deviation from thermodynamic control and sub-optimal performance. Optimum PEM fuel cell operation is shown to occur when a fully humidified cathode feed is maintained in association with a highly humidified anode feed; the precise value of which is determined by a balance between membrane hydration and catalyst flooding. The limiting current density is dominated by membrane dehydration but is also shown to result from flooding of the cathode catalyst, depending on cathode air flow rate and relative humidity. This work is believed the first time that both failure modes have been experimentally observed due to varying operating conditions for a given system. Cathode catalytic activity is shown to be enhanced by humidification until flooding occurs. The precise cause of this activity enhancement has yet to be determined. Finally, fully humidifying the inlet gas feed on either electrode is usually found to reduce membrane resistance with different efficiencies depending on cathode air flow rates.
Anastasios Angelopoulos, PhD (Committee Chair)
Junhang Dong, PhD (Committee Member)
Peter Panagiotis Smirniotis, PhD (Committee Member)
101 p.
Chemical Engineering
PEM fuel cells; humidity control; AC impedance spectroscopy; water management

Recommended Citations

Citations

  • Tan, L. (2010). AC Impedance Spectroscopy Analysis of Improved Proton Exchange Membrane Fuel Cell Performance via Direct Inlet Humidity Control [Master's thesis, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1282322171

    APA Style (7th edition)

  • Tan, Li. AC Impedance Spectroscopy Analysis of Improved Proton Exchange Membrane Fuel Cell Performance via Direct Inlet Humidity Control. 2010. University of Cincinnati, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1282322171.

    MLA Style (8th edition)

  • Tan, Li. "AC Impedance Spectroscopy Analysis of Improved Proton Exchange Membrane Fuel Cell Performance via Direct Inlet Humidity Control." Master's thesis, University of Cincinnati, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1282322171

    Chicago Manual of Style (17th edition)

ucin1282322171
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© 2010, all rights reserved.
This open access ETD is published by University of Cincinnati and OhioLINK.