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Overarching Themes
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Hydrogen electrolysis 3.3.2017

Concept for construction of the prototype system
© Fraunhofer HHI FS-M

Green H2: Producing low cost and load-flexible hydrogen

Innovative electrodes improve hydrogen electrolysis for a wide output range. With their laser-etched surface structures, they are durable and have lower losses at different loads. As a result, the electrodes are particularly good at using the fluctuating supply of excess wind electricity. If upscaled, the structured electrodes can also be used in industrial applications.

Project status
Project duration June 2015 until May 2018

Due to the significant fluctuation of renewable energy technologies, energy conversion machines suitable for flexible loads must be developed. Storing electricity from excess production is one of the key challenges for the future energy market – so converting this electricity into hydrogen as an energy source is an attractive alternative.

The load properties and electrode working life are to be improved significantly using innovative electrode materials. For this purpose, the surfaces are etched with ultrashort laser pulses. This forms a regular conical structure, micrometres in size, enlarging the specific surface and improving the chemical properties.

At the start of the project, researchers used the existing laser system in the first year to develop the electrodes in order to find and test the most promising structures. At the same time, they upscaled the laser process to accelerate processing of the required surfaces. In the second year, development of the electrodes was completed and the researchers worked to build the high performance laser system. They also made initial tests and transferred the structures to the new laser parameters. The focus is now on integrating the electrodes in a short stack, including test operation, as well as improving the process further. Throughout the entire duration, the researchers are characterising the structures, as well as tracking and evaluating economic and technical aspects.

  • REM image of the structured nickel surface © Fraunhofer HHI FS-M
  • Final structure of the process chamber © Fraunhofer HHI FS-M
  • Accelerated stress test of the electrodes, overload properties © Fraunhofer IFAM Dresden
  • Laser-structured surfaces with Ti:Sa laboratory laser (left: test rig, right: schematic) © Fraunhofer HHI FS-M
  • Measurement setup for electrode characterisation © Fraunhofer IFAM Dresden

Current work

The innovative electrode structure is characterised by a high load flexibility and lower losses. It makes using electrolysis far more attractive for storing energy as hydrogen. To use this technology in an industrial context, the researchers want to upscale the surface area of the structured electrodes from a laboratory scale to a size suitable for industrial systems. Besides developing suitable structures, this is the key challenge of the project. As a result, a range of companies and research institutes are involved as partners to make the project a success: Fraunhofer Heinrich Hertz Institute HHI, Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, AMPHOS, metal finishing company MTV, ELB, Miopas and Protronic.

Research focus

The GreenH2 project is an interdisciplinary research project; it combines applied photonics with electrolysis and industrial process control. The developments in functionalising surfaces with ultrashort-pulse lasers are a relatively new technology, which permits precise adjustment of the required parameters or properties of the surface in most cases. That guarantees high precision and reproducibility for the process. In contrast to this, alkaline electrolysis of hydrogen has been in existence for much longer and advancements through research have been rare in the past decades. Improving the electrodes via structuring is likely to make alkaline electrolysis suitable for a far wider range of applications, allowing it to integrate well into the system of modern energy storage facilities.

Sub-projects

  • Fraunhofer HHI:
    Processing the laboratory series of electrodes with Ti-Sa femtosecond lasers to determine laser parameters, transfer and verification of the parameters and results of the Ti:Sa laser system to the AMPHOS high-performance laser system at a laboratory scale, setup and integration of the laser scanner, studies on the design and construction of the process chambers, commissioning the overall system, optimising the overall system (process stability, homogeneity of the micro-structuring, write speed), production of small series of optimised micro-structured electrodes 0.25 m2 in size
  • Fraunhofer IFAM:
    General characterisation of the structured electrodes (morphology, surface determination, roughness determination, surface composition), electrochemical characterisation (determination of overvoltage, determination of electrochemically active surface, determination of table parameters), installation of test electrodes (laboratory series) in special test cells for testing materials under real conditions (comparison with commercial electrodes, determining corresponding figures), degradation test (operation of test electrodes under overload conditions), testing the established electrode structures (short run) under normal conditions and overload behaviour
  • AMPHOS GmbH:
    Transfer and verification of parameters and results of the Ti:Sa laser system to the AMPHOS high-performance laser system, commissioning the overall system, optimisation of the overall system (process stabilisation, homogeneity of micro-structuring, write speed)
  • MIOPAS GmbH:
    Identification of the necessary process gases for electrode structuring, separation concept for the laser ablation process products created in the structuring process, studies of the design and construction of the process chamber, commissioning of the overall system
  • Protronic Innovative Steuerungselektronik GmbH:
    Formulation of the integration concept, determination of the interfaces required for laser process monitoring, development of the laser safety concept, study on the design and construction of the process chamber, determination and implementation of the interfaces in the process chamber for the overall control and monitoring unit, commissioning of the overall system
  • MTV Metallveredlung GmbH & Co. KG:
    Production of different metal and/or catalyst alloys as a coating on test substrates (laboratory series), comparison of the coating concepts, short run processing of optimised micro-structured electrodes (coating)
  • ELB Elektrolysetechnik GmbH:
    Construction of a small electrolyser for short runs with corresponding peripherals, long-term test for extrapolation to 10 years of continuous operation
Supported by: The Federal Government on the basis of a decision by the German Bundestag

Dates

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Infobox

Research funding

The information system EnArgus provides information on research funding, including on this project (German only).