Teamwork for the energy of tomorrow
Maxnet Energy brings together key competencies from eight Max Planck Institutes and two international partners
Scientists are contributing their specialized know-how to make water electrolysis more efficient as a central component of sustainable energy supply. And additional international partners have now come on board as well.
To be able to store the energy acquired from wind generators or solar energy systems on a large scale – this is the primary prerequisite for the success of the energy transformation. A few start-ups, but also large corporations, are already working with “power-to-gas” systems. These systems generate hydrogen during the process of electrolysis using energy from renewable sources. The benefit: in this form, energy – in contrast to green electricity – can be stored and used when needed. “The electrolysis of water may be an established technology, but there is still considerable room for improvement,” emphasizes Alexander Auer, researcher at the MPI for Chemical Energy Conversion (MPI CEC) in Mülheim a.d.R. and scientific coordinator of Maxnet Energy.
The research alliance is now lining up to optimize the electrolysis of water – i.e. the generation of hydrogen via the splitting of water using electricity. The partners are focusing on the partial reaction of the process, as this is where most of the problems lie at the moment: the formation of oxygen. Here, the industry is facing a difficult choice. It can either rely on the robust and powerful catalyst iridium dioxide, which is very expensive, or turn to cost-efficient alternatives, which do not last very long. This is because the conditions on the electrode – where the oxygen is formed when the water is split – are very aggressive and most materials are affected by this. Maxnet Energy wants to find a way around the dilemma of having to choose between expensive and sustainable or cheap and sensitive.
Variety of specialist disciplines
Scientists from a wide range of disciplines are involved – including scientists from the MPI CEC and the Max-Planck-Institut für Eisenforschung (Iron Research) (Düsseldorf) and Max Planck Institut für Kohlenforschung (Coal Research) (Mülheim a.d.R.), as well as the Max Planck Institutes for Polymer Research (Mainz), Colloids and Interfaces (Potsdam), the Fritz Haber Institute of the MPG in Berlin, the Max Planck Institute for Chemical Physics of Solids in Dresden, the Max Planck Institute for Dynamics of Complex Technical Systems in Magdeburg, the Cardiff Catalysis Institute, UK, and the University of Virginia, USA. The spectrum of disciplines involved – from catalyst researchers to materials scientists and control technicians – is explained by the fact that although the research objective can be very specifically defined, the problems en route to achieving this objective are multifaceted. “Until now, it has not been clear why iridium dioxide works so well as a catalyst and why the catalysts that are free of precious metals aren’t very long lasting,” says Auer.
While this question is being clarified by the catalyst researchers at the MPIs, the partners from Cardiff are concentrating on the structural variety of the materials. “They can manufacture various types of iridium dioxide in a targeted manner, and we then examine them,” says Auer. During electrolysis, however, the material changes. How its structure changes and how it is affected by corrosion also depends on how the voltage is controlled at the electrolysis cell. This is a question of control technology and falls to the specialists of the Max Planck Institute for Dynamics of Complex Technical Systems. Scientists here can carry out experiments on a much larger scale, bringing them that much closer to the industrial reality.
Next objectives in sight
Parallel to this, a search is being carried out for alternatives to iridium dioxide. Of course, these have to be manufactured first. “The synthesis of catalytically active substances is one of the strengths of the colleagues from the University of Virginia,” says Auer. The US colleagues, who signed the cooperation agreement early this year, are also active in the area of photoelectrocatalysis. “We therefore also have long-term perspectives in our sights at Maxnet Energy,” says Auer. He explains that photoelectrocatalysis would enable water to be broken down into hydrogen and oxygen using the energy from sunlight, thereby removing the intermediate step of power generation from the equation. This is also only possible with suitable catalysts, and this is something the partners are already working on.
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