Researchers from Imec and KU Leuven have shown that they can make electrochemical reactions, such as the production of hydrogen via electrolysis, much more efficient using a new nanomaterial.
Expectations about green hydrogen as the fuel of the future are high. But the production of the gas with renewable energy cannot yet compete economically with more polluting production techniques based on fossil energy. This has a lot to do with the limited efficiency of electrolysis installations, in which water is split into hydrogen and oxygen gas using electricity.
The splitting reaction takes place on the surface of electrodes (electrical conductors) that are immersed in a water bath. Industrial electrolysers are made up of hundreds of electrolysis cells connected in series, each with two electrodes, sometimes up to 2 meters wide.
The electrodes in alkaline electrolysers, one of the most commonly used types, typically consist of ‘nickel foam’: nickel in a 3D structure reminiscent of chicken wire. The Leuven researchers were able to process the nickel in a nanostructure that is just as porous, but much more finely meshed. The nanomaterial is made up of threads barely 40 nanometers thick, one thousandth of a human hair.
- By pouring nickel into a superporous 3D nanostructure, researchers from Leuven were able to make a much more efficient electrode.
- The technology can make the production of green hydrogen via electrolysis much more efficient.
- The technique also has other possible applications, such as batteries or CO₂ reduction.
‘In a traditional electrode you have openings of 100 microns. In our material, they barely measure 50 nanometers, about a thousand times smaller’, says Philippe Vereecken, Imec fellow and part-time professor at KU Leuven. Until recently, the nanomaterial still had to be supported by a non-porous carrier, but now the people of Leuven have succeeded in extending the porous structure throughout the entire electrode.
In a classic electrode you have openings of 100 microns. In our material, they barely measure 50 nanometres, a thousand times smaller.
The result is an electrode with a larger reaction surface that can discharge the formed hydrogen gas more quickly. Both factors make the electrolysis process a lot more efficient: with the same amount of energy, more current can be passed through the electrode and more hydrogen can be formed. At lab level, we speak of an output that is dozens of times higher. It is not yet clear to what extent this advantage extends to an industrial scale.
‘The production of the nanomaterial takes place in an atmospheric process that can be scaled up perfectly. We use a kind of molds in which the 3D structure forms itself’, says Bart Onsia, business development manager at Imec/EnergyVille. This scalability is important to be able to take the new technology from the lab to a commercial environment. Onsia thinks the nanomaterial will be used in commercial applications ‘before the end of this decade’.
To further develop the possibilities for hydrogen production, the Hyve spin-off was founded last year. Together with partners VITO, DEME, John Cockerill, Colruyt and Bekaert, the company continues to develop components for electrolysis installations. A possible future for the technology is the production of hydrogen at sea, in offshore wind farms. This requires compact installations with a large capacity.
There are other possible applications, such as in hydrogen cells and small batteries. By applying the nanostructure in other materials, other applications become possible. ‘If we use copper or silver instead of nickel, the technique can also be used to convert CO₂ into other raw materials,’ says Vereecken. ‘We are conducting further research into this with the VITO research institute.’