TY - JOUR

T1 - Model-based analysis of low stoichiometry operation in proton exchange membrane water electrolysis

AU - Immerz, Christoph

AU - Bensmann, Boris

AU - Hanke-Rauschenbach, Richard

N1 - Funding Information: Funding: The authors gratefully acknowledge the financial support by the Federal Ministry of Education and Research of Germany in the framework of PowerMem (project number 03EW0012B).

PY - 2021/9/9

Y1 - 2021/9/9

N2 - Proton exchange membrane water electrolysis cells are typically operated with high water flow rates in order to guarantee the feed supply for the reaction, the hydration of the ionomer phase and to homogenize the temperature distribution. However, the influence of low flow rates on the cell behavior and the cell performance cannot be fully explained. In this work, we developed a simple 1+1-dimensional mathematical model to analyze the cell polarization, current density distribution and the water flow paths inside a cell under low stoichiometry condition. The model analysis is in strong context to previous experimental findings on low water stoichiometry operations. The presented analysis shows that the low water stoichiometry can lead to dry-out at the outlet region of the anode channel, while a water splitting reaction is also present there. The simulation results show that the supply with water in this region is achieved by a net water transport from the cathode to the anode catalyst layer resulting in higher local proton resistances in the membrane and the anode catalyst layer.

AB - Proton exchange membrane water electrolysis cells are typically operated with high water flow rates in order to guarantee the feed supply for the reaction, the hydration of the ionomer phase and to homogenize the temperature distribution. However, the influence of low flow rates on the cell behavior and the cell performance cannot be fully explained. In this work, we developed a simple 1+1-dimensional mathematical model to analyze the cell polarization, current density distribution and the water flow paths inside a cell under low stoichiometry condition. The model analysis is in strong context to previous experimental findings on low water stoichiometry operations. The presented analysis shows that the low water stoichiometry can lead to dry-out at the outlet region of the anode channel, while a water splitting reaction is also present there. The simulation results show that the supply with water in this region is achieved by a net water transport from the cathode to the anode catalyst layer resulting in higher local proton resistances in the membrane and the anode catalyst layer.

KW - 1+1-dimensional modeling

KW - Current density distribution

KW - Low stoichiometry operation

KW - Proton exchange membrane water electrolysis

UR - http://www.scopus.com/inward/record.url?scp=85115123884&partnerID=8YFLogxK

U2 - 10.3390/membranes11090696

DO - 10.3390/membranes11090696

M3 - Article

AN - SCOPUS:85115123884

VL - 11

JO - Membranes

JF - Membranes

IS - 9

M1 - 696

ER -