New hope in the fight against wa­ter short­age: in­nov­at­ive de­sal­in­a­tion bat­ter­ies could be the solu­tion

Research award winner presents results at Research Day

Water is one of the world's most precious resources, needed in industry, agriculture and for our everyday survival - provided it is clean. Desalination batteries play a crucial role in this. They remove dissolved substances from the water and thus prepare it for various applications. But: "The technology is in need of expansion," says Jun.-Prof. Dr. Hans-Georg Steinrück from Paderborn University. Two years ago, the chemist was awarded the university's research prize for his approach to developing new desalination battery concepts. Now he has presented his results.

"In view of the rising world population, increasing industrialisation and climate change, the global water shortage could increase dramatically in the near future," Steinrück emphasises. Desalination batteries are considered by him to be a promising hope to counteract this crisis. "The process is relatively simple: electrodes pick up dissolved components such as salt and remove them from the water by adding electrical energy. The crux of the matter is that not all undesirable substances can be completely removed," Steinrück continues.

That is why his team developed a new approach for desalination reactors. The aim was to improve the binding of the particles that make the water undrinkable and to make the electrodes more efficient by using new surface layers. The researchers around Steinrück used state-of-the-art electrochemical methods as well as X-ray and spectroscopy techniques, including synchrotron-based high-energy X-ray diffraction, to investigate changes in the electrodes - down to the smallest detail.

A key result is an atomic understanding of ion deposition for desalination batteries for lithium extraction from seawater. "This opens up the possibility of using desalination batteries for a wider range of applications. For example, for the extraction of rare raw materials such as lithium from saline thermal water deposits underground," explains Steinrück.

A completely new field of application is electrocatalysts, especially for hydrogen production. Here, the batteries could eliminate unwanted ions before they take part in catalyst-poisoning reactions. This would significantly reduce energy-intensive steps for water treatment. The scientists have already quantified the efficiency of the batteries and of water splitting by electrolysis, which offers promising prospects.  This makes it possible to measure exactly which processes lead to inefficiencies.

Steinrück: "We have gained initial insights into the functioning of surface layers that could increase the energy efficiency of desalination batteries. This opens up new possibilities for future electrode materials in the fight against the global water shortage."

This text has been translated automatically.