Solar Hydrogen

Contact person:

Prof. Dr. et Ing. habil. Kerstin Eckert

Dr. Xuegeng Yang 

Person involved:

Dipl.-Ing. Hannes Rox

Funding agency: Helmholtz Assoziation

Project period: 1.1.2021 - 31.12.2023

Profile:

Water electrolysis, bubble dynamics, multiphase flow

Description:

The project is part of the Helmholtz Innovation Pool and is worked together with multiple Helmholtz – Centers (see Partners). The goal of Solar Hydrogen is the production of highly pure and compressed hydrogen using solar energy. Therefore, a combination of fundamental and application-oriented research is needed to develop viable technologies at low capital and operational expenditures (CAPEX and OPEX). Thus, this can make an important contribution to achieve a sustainable energy system in Germany.

© Hannes Rox

One approach is the redesign of current alkaline electrolysis cells. By eliminating the diaphragm normally used in such cells, the CAPEX can be reduced drastically. In the so-called membraneless electrolyzers, the electrolyte flow is used to separate the products H₂ and O₂. However, this leads to disadvantages like e.g., higher ohmic losses due to the larger electrode gap. For this purpose, a new cell is developed to perform parametrical studies of the dependance of the hydrogen purity on parameters like the electrode gap or the flow rate.

Additional, bubble dynamics on porous electrodes are studied in detail (see figure), since they are crucial for membraneless electrolyzers, but also widely used in other technologies. Here, the focus is on the study of the dependency of the bubble dynamics on the electrode surface and geometry. The experimental tools combined with the developed image analysis algorithms enable to investigate as well as validate new surface structuring (e.g., laser-structuring) in respect to improved bubble growth and detachment.

Goals:

• Development of a membraneless alkaline electrolyzer
• Detailed study of the bubble dynamics produced in alkaline electrolytes at porous electrodes

Methods:

• Shadowgraphy
• Particle Image Velocimetry (PIV)
• Cyclic Voltammetry
• Linear Sweep Voltammetry
• Galvanotstatic and potentiostatic measurements

Publications

[1] Bashkatov, Aleksandr, et al. „Dynamics Of Single H₂ Bubbles During Water Electrolysis“. FC³ Fuel Cell Conference. Chemnitz. (2022)

Partners:
Forschungszentrum Jülich (FZJ)

Deutsches Zentrum für Luft- und Raumfahrt (DLR)

Karlsruhe Institute of Technology (KIT)

Helmholtz-Zentrum Berlin (HZB)

Helmholtz-Zentrum Dresden-Rossendorf (HZDR)

Max-Planck-Institut für Plasmaphysik (IPP)