Is glass battery technology legitimate

Transport: air and lithium: the dream of the super battery

It rolls and rolls and rolls and - no longer rolls: electric cars still have a range that is too short. Battery technology is not yet mature. It's too heavy, too expensive, takes too long to load. Therefore, the big manufacturers and universities all over Germany are looking for new opportunities. One of the leading research institutions is the MEET battery research center at the University of Münster.

There a small amount of clear liquid raises high hopes. It should make it possible: the competitive electric car. In the chemistry laboratory in Münster, researchers are working on a lithium-air battery. The glass container with the blue lid contains only a few milliliters of the liquid. At first glance, it could be water. But the liquid should be able to do much more.

The starting conditions are always the same: In order to generate energy for driving, the lithium ions flow back and forth between two parts of a battery - the anode and the cathode. In order for this to work, the ions at these two locations still have to be trapped in a type of container molecule, much like water in a bucket.

The horse's foot: The containers are heavy and otherwise completely useless. "In today's lithium-ion battery, you therefore carry more than 300 grams of container molecules for 10 grams of lithium," explains Stefano Passerini from the MEET battery research center at the University of Münster. That makes the batteries of the electric cars so heavy and the range of around 150 kilometers so short.

"Lithium-air systems have the potential to increase the achievable range," says the technical director of the Association of the Automotive Industry (VDA), Hans-Georg Frischkorn. "However, it's not just about the range. The overall package of long service life, high charging capacity, low weight, competitive costs and an appropriate range has to be right."

The idea of ​​the lithium-air battery is to leave out the heavy container molecules and build a battery that only works with lithium and air. What sounds simple has given researchers headaches for years. Several research projects on lithium-air batteries have started in Münster in recent months.

"One of the biggest problems is that lithium reacts with almost everything we know," says Passerini. Problems arise especially when lithium comes into contact with the water in the air. "Then hydrogen is formed and after a short time the battery will fly around your ears."

In order to prevent the reaction of lithium with water and other substances, the researchers want to fill the inside of their lithium-air battery - the space between anode and cathode - with so-called ionic liquids. Chemically, these liquids are something like table salt. "Only our salts are liquid at room temperature," explains the chemist.

But which ionic liquid should it be? In order to find the perfect material, the Münster researchers experiment with a wide variety of variants. "We can expand the basic structure at various points and thus change the material properties." There are a lot of questions: How conductive is the new material? Where is the melting point? Which electrical voltages can it withstand? At what temperature will it be destroyed?

There is still a long way to go before the lithium-air battery is ready for the market - and the researchers from Münster are working on just one of many problems. "The lithium-air technology has great potential, but is currently far from being technically mature and is still in the area of ​​basic research," says VDA boss Frischkorn. "That is why nobody can say with certainty today whether and when the lithium-air battery will be used." The National Platform for Electric Mobility sees it as an option for the period after 2025. (dpa)

MEET website