Water is probably the most important resource in the world. We need it in industry, in agriculture, to survive – provided it is clean water, of course. And this is where “desalination batteries” can help. These remove dissolved substances from the water, thereby preparing it for a wide variety of applications. The problem: Research into these devices is still in its infancy. With his approach to developing innovative concepts for desalination batteries, in particular with regard to new functionalities, chemist and junior professor Dr Hans-Georg Steinrück has now been honoured with this year’s Paderborn University Research Prize, which carries a cash value of €150,000.
“Billions of people suffer from a lack of drinking water. With the ever-growing world population, increasing global industrialisation and climate change, this shortage is anticipated to worsen dramatically in the future – a global issue that requires immediate attention,” warns Steinrück.
For the scientist, desalination batteries are a beacon of hope as a possible way out of the crisis. The process in brief: Electrodes absorb dissolved components, such as salt, and remove them from the water by adding electrical energy. The problem is that this removes many, but not all of the ‘culprits’. Steinrück believes that the technology has further potential, and is therefore working on improving the binding of the particles that make water undrinkable and rendering the electrodes more efficient through new surface layers. To this end, he is investigating the functioning of the batteries down to the minutest detail – the atomic level – using state-of-the-art electrochemical methods, as well as X-ray and spectroscopy techniques.
Steinrück explains: “We want to exploit both the ideal and actual properties of the electrodes. To do this, we’re researching materials whose equilibrium energies and ion transport velocities are aligned in such a way that ‘ion A’ is given preference over ‘ion B’, while another material behaves in the opposite way; we’re talking here about ion selectivity. If successful, the range of applications for desalination batteries could be significantly expanded, for example, to extract rare raw materials such as lithium, which is found underground in saline thermal waters.”
One completely new field for the use of desalination batteries is electrocatalysts, which are used in hydrogen production, for example. Hydrogen is obtained by splitting water with the help of electrical energy. “We assume that desalination battery carriers ‘suck away’ unwanted ions before they can take part in catalyst-poisoning reactions. This could, in particular, help avoid the need for the kind of energy-intensive steps involved in water treatment,” explains the chemist. The scientists in Steinrück’s team have set themselves a further goal: They want to develop multi-functional surface layers for desalination batteries. In the future, this could provide for new electrode materials in the fight against the global water crisis. The chemists plan to present their results in 2023; preliminary results are expected sooner.