Challenges and important considerations when benchmarking single-cell alkaline electrolyzers

Cinar Karacan, Felix P. Lohmann-Richters, Gareth P. Keeley, Fabian Scheepers, Meital Shviro, Martin Müller, Marcelo Carmo, Detlef Stolten

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


This study outlines an approach to identifying the difficulties associated with the benchmarking of alkaline single cells under real electrolyzer conditions. A challenging task in the testing and comparison of different catalysts is obtaining reliable and meaningful benchmarks for these conditions. Negative effects on reproducibility were observed due to the reduction in conditioning time. On the anode side, a stable passivation layer of NiO can be formed by annealing of the Ni foams, which is even stable during long-term operation. Electrical contact resistance and impedance measurements showed that most of the contact resistance derived from the annealed Ni foam. Additionally, analysis of various overvoltages indicated that most of the total overvoltage comes from the anode and cathode activation overpotential. Different morphologies of the substrate material exhibited an influence on the performance of the alkaline single cell, based on an increase in the ohmic resistance.

Original languageEnglish
Pages (from-to)4294-4303
Number of pages10
JournalInternational Journal of Hydrogen Energy
Issue number7
StatePublished - 22 Jan 2022
Externally publishedYes

Bibliographical note

Funding Information:
The authors gratefully acknowledge experimental support from Daniel Holtz, Norbert Commerscheidt, Sebastian Holtwerth, and Andreas Everwand. We would also like to convey our thanks to the HYPOS Hydrogen Power Storage & Solutions East Germany initiative, funded by the German Federal Ministry of Education and Research (BMBF) as part of the “Twenty 20 - Partnership for Innovation” program, within the framework of the ELKE Project #03ZZ0704A.

Publisher Copyright:
© 2021 The Authors


  • Alkaline electrolyzers
  • Benchmarking
  • Electrodes
  • Harmonization
  • Hydrogen


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