Details
| Original language | English |
|---|---|
| Pages (from-to) | F645-F652 |
| Journal | Journal of the Electrochemical Society |
| Volume | 166 |
| Issue number | 10 |
| Early online date | 25 Jun 2019 |
| Publication status | E-pub ahead of print - 25 Jun 2019 |
Abstract
The degradation of proton exchange membrane water electrolysis cells is usually measured in a temporal increase of the cell voltage. Although this is sufficient to evaluate the stability of a system, it is less suitable for targeted material development. Thus, an overpotential-specific and temporally resolved electrochemical characterization protocol is proposed. In this the ohmic overpotential is determined with high frequency resistance measurements. These are also used in combination with polarization curves to distinguish between the kinetic and mass transport overpotentials and to determine kinetic key parameters, according to the Butler-Volmer and transition state theory. Complementary electrochemical impedance spectroscopy measurements further unravel the individual resistances. On this basis, the following statements can already be issued. The major share of the measured cell voltage increase, i.e. degradation, is of apparent nature as it is recovered once lower potentials are applied. It is suggested that this is due to changes in the oxidation states of the iridium-based catalyst. Real degradation occurs in the ohmic and mass transport overpotential mainly at higher current densities and longer operating times. The increasing kinetic overpotential with increasing operating time is primarily potential-driven. Interestingly, both the Tafel slope and the apparent exchange current density slightly increase over time.
ASJC Scopus subject areas
- Materials Science(all)
- Electronic, Optical and Magnetic Materials
- Energy(all)
- Renewable Energy, Sustainability and the Environment
- Materials Science(all)
- Surfaces, Coatings and Films
- Chemistry(all)
- Electrochemistry
- Materials Science(all)
- Materials Chemistry
Sustainable Development Goals
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In: Journal of the Electrochemical Society, Vol. 166, No. 10, 25.06.2019, p. F645-F652.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Degradation of Proton Exchange Membrane (PEM) Water Electrolysis Cells: Looking Beyond the Cell Voltage Increase
AU - Suermann, Michel
AU - Bensmann, Boris
AU - Hanke-rauschenbach, Richard
N1 - Funding information: The authors gratefully acknowledge the financial support by the Federal Ministry of Education and Research of Germany in the frame-work of PowerMEE (project number 03SF0536B).
PY - 2019/6/25
Y1 - 2019/6/25
N2 - The degradation of proton exchange membrane water electrolysis cells is usually measured in a temporal increase of the cell voltage. Although this is sufficient to evaluate the stability of a system, it is less suitable for targeted material development. Thus, an overpotential-specific and temporally resolved electrochemical characterization protocol is proposed. In this the ohmic overpotential is determined with high frequency resistance measurements. These are also used in combination with polarization curves to distinguish between the kinetic and mass transport overpotentials and to determine kinetic key parameters, according to the Butler-Volmer and transition state theory. Complementary electrochemical impedance spectroscopy measurements further unravel the individual resistances. On this basis, the following statements can already be issued. The major share of the measured cell voltage increase, i.e. degradation, is of apparent nature as it is recovered once lower potentials are applied. It is suggested that this is due to changes in the oxidation states of the iridium-based catalyst. Real degradation occurs in the ohmic and mass transport overpotential mainly at higher current densities and longer operating times. The increasing kinetic overpotential with increasing operating time is primarily potential-driven. Interestingly, both the Tafel slope and the apparent exchange current density slightly increase over time.
AB - The degradation of proton exchange membrane water electrolysis cells is usually measured in a temporal increase of the cell voltage. Although this is sufficient to evaluate the stability of a system, it is less suitable for targeted material development. Thus, an overpotential-specific and temporally resolved electrochemical characterization protocol is proposed. In this the ohmic overpotential is determined with high frequency resistance measurements. These are also used in combination with polarization curves to distinguish between the kinetic and mass transport overpotentials and to determine kinetic key parameters, according to the Butler-Volmer and transition state theory. Complementary electrochemical impedance spectroscopy measurements further unravel the individual resistances. On this basis, the following statements can already be issued. The major share of the measured cell voltage increase, i.e. degradation, is of apparent nature as it is recovered once lower potentials are applied. It is suggested that this is due to changes in the oxidation states of the iridium-based catalyst. Real degradation occurs in the ohmic and mass transport overpotential mainly at higher current densities and longer operating times. The increasing kinetic overpotential with increasing operating time is primarily potential-driven. Interestingly, both the Tafel slope and the apparent exchange current density slightly increase over time.
UR - http://www.scopus.com/inward/record.url?scp=85068335812&partnerID=8YFLogxK
U2 - 10.1149/2.1451910jes
DO - 10.1149/2.1451910jes
M3 - Article
VL - 166
SP - F645-F652
JO - Journal of the Electrochemical Society
JF - Journal of the Electrochemical Society
SN - 0013-4651
IS - 10
ER -