TY - JOUR

T1 - Relating the N-shaped polarization curve of a PEM fuel cell to local oxygen starvation and hydrogen evolution

AU - Zamel, Nada

AU - Hanke-Rauschenbach, Richard

AU - Kirsch, Sebastian

AU - Bhattarai, Arjun

AU - Gerteisen, Dietmar

N1 - Funding information: The Fraunhofer-Institute for Solar Energy Systems (ISE) and the Max Planck Institute for Dynamics of Complex Technical Systems gratefully acknowledge financial support from German Federal Ministry of Education and Research (BMBF) under the project “GECKO”, Grant No. 03SF0454A and 03SF0454B , respectively. The author N. Zamel would like to gratefully acknowledge the financial support of Natural Sciences and Engineering Research Council of Canada (NSERC) in the form of a Postdoctoral Fellowship.

PY - 2013/11/22

Y1 - 2013/11/22

N2 - In this study, we experimentally investigate the appearance of a local negative differential resistance (N-NDR) branch in polarization curves of a segmented 7 by 7 cell measured under the steady and highly-dynamic conditions. Under both conditions, a comma shaped polarization curve, corresponding to depletion of oxygen, was followed by an increase in current as the cell voltage was lowered. This characteristic was measured under potentiostatic mode, where no current is forced through the cell, and at a positive cell voltage (<100 mV in steady-state and ∼300 mV in dynamic condition). With a theoretical model, we show that at these positive cell voltages and upon the depletion of oxygen, a shift in the Nernst potential occurs allowing for the hydrogen evolution reaction to take place in the cathode catalyst layer. The results of the model are complemented with experimental measurements of produced hydrogen at the cathode outlet.

AB - In this study, we experimentally investigate the appearance of a local negative differential resistance (N-NDR) branch in polarization curves of a segmented 7 by 7 cell measured under the steady and highly-dynamic conditions. Under both conditions, a comma shaped polarization curve, corresponding to depletion of oxygen, was followed by an increase in current as the cell voltage was lowered. This characteristic was measured under potentiostatic mode, where no current is forced through the cell, and at a positive cell voltage (<100 mV in steady-state and ∼300 mV in dynamic condition). With a theoretical model, we show that at these positive cell voltages and upon the depletion of oxygen, a shift in the Nernst potential occurs allowing for the hydrogen evolution reaction to take place in the cathode catalyst layer. The results of the model are complemented with experimental measurements of produced hydrogen at the cathode outlet.

KW - Hydrogen evolution reaction

KW - Negative differential resistance

KW - Oxygen depletion

KW - Polarization curve

KW - Hydrogen evolution reaction

KW - Negative differential resistance

KW - Oxygen depletion

KW - Polarization curve

UR - http://www.scopus.com/inward/record.url?scp=84887108340&partnerID=8YFLogxK

U2 - 10.1016/j.ijhydene.2013.09.130

DO - 10.1016/j.ijhydene.2013.09.130

M3 - Article

AN - SCOPUS:84887108340

VL - 38

SP - 15318

EP - 15327

JO - International Journal of Hydrogen Energy

JF - International Journal of Hydrogen Energy

SN - 0360-3199

IS - 35

ER -