Contact

Dr. Xuegeng Yang

Head Electrochemical Systems
x.yangAthzdr.de
Phone: +49 351 260 3863
Fax: +49 351 260 13863

Electrode performance and degradation test

Nickel electrodes are widely used in alkaline water electrolysis, but the electrode overpotentials remain high, resulting in significant losses. Improving bubble management on industrially relevant electrodes is therefore beneficial, as bubbles lead to increased ohmic resistance and block the active electrode area.

Goals

One promising approach is to functionalize the electrode surface to modify the surface wettability and increase the electrochemically active surface area. In order to characterize the electrode performance, a 3-electrode cell was developed in which the electrode can be optically studied from two perspectives during the O2 or H2 evolution reaction. Thus, in addition to standard electrochemical parameters such as double layer capacitance or onset potential, the detached bubble sizes and the covered electrode surface can be analyzed. This allows to tune the electrode surface and the bubble management towards highly efficient electrodes. The optimized electrodes are then tested for long-term stability using electrochemical methods.

Methods

  • Optical methods:

     (High speed) Shadowgraphy
     Machine-learning based image segmentation

  • Electrochemical methods:

     Galvanostatic/Potentiostatic measurements
     Linear Sweep Voltammetry
    Cycle voltammetry
    Electrochemical impedance spectroscopy

Results

Using machine learning based image segmentation, the detached bubble size distribution and the number of nucleation sites were studied as shown in the exemplary images in the following Figure. Here, laser structuring was used to functionalize the surface, which led to an increase of detached bubble sizes (see Figure (c)), while the number of nucleation sites decreased. In combination with an increase in ECSA, the overpotential were significantly lower (≈ −164 mV at 100 mA cm−2) compared to the non-structured Ni-foils, as shown in Figure (d).

Example images of the (a) side- and (b) topview with highlighted detected bubbles.Comparison of (c) bubble size distributions and (d) electrode potential during galvanostatic measurements at an applied current density of 100 mAcm–2 of non- and laser-structured surfaces.

Partners:

  • Institute Solar Fuels, Helmholtz Zentrum Berlin
  • Chair of Laser-Based Manufacturing, TU Dresden
  • Fraunhofer Institute for Manufacturing Technology and Advanced Materials, IFAM, Dresden

Involved Projects

  • Solar Hydrogen (finished)
  • Nanocones (finished)
  • H2 Lab
  • ALKALIMIT

Main Publications

  1. Hannes Rox, Fabian Ränke, Jonathan Mädler, Mateusz M. Marzec, Krystian Sokolowski, Robert Baumann, Homa Hamedi, Xuegeng Yang, Gerd Mutschke, Leon Urbas, Andrés Fabián Lasagni, Kerstin Eckert. Boosting electrode performance and bubble management via Direct Laser Interference Patterning. Submitted to ACS Applied Materials & Interfaces, 2024. DOI: 10.48550/arXiv.2411.03373
  2. Hannes Rox, Aleksandr Bashkatov, Xuegeng Yang, Stefan Loos, Gerd Mutschke, Gunter Gerbeth, Kerstin Eckert. Bubble size distribution and electrode coverage at porous nickel electrodes in a novel 3-electrode flow-through cell. International Journal of Hydrogen Energy , 48, 8, 2892-2905, 2023. DOI: 10.1016/j.ijhydene.2022.10.165
  3. Lukas Krause, Katarzyna Skibińska, Hannes Rox, Robert Baumann, Mateusz M. Marzec, Xuegeng Yang, Gerd Mutschke, Piotr Żabiński, Andrés Fabián Lasagni, Kerstin Eckert. Hydrogen Bubble Size Distribution on Nanostructured Ni Surfaces: Electrochemically Active Surface Area Versus Wettability. ACS Applied Materials & Interfaces, 15, 14, 18290-18299, 2023. DOI: 10.1021/acsami.2c22231