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Australian and German researchers have applied for a patent for a new type of lithium-sulfur battery that is much lighter, cleaner and more powerful than the currently standard lithium-ion batteries used in electric cars and mobile phones.

The universities involved are Monash from Australia, the Technical University of Dresden and the Fraunhofer Institute IMS in Duisburg.

In the habit of breaking down too soon

The advantages of lithium-sulfur batteries have been known for a long time. However, there is one major problem. The cathode (electrical conductor) in the battery, which consists of sulfur, was very fragile up until now. It was in the habit of always breaking down after a few hundred recharges. That’s why the Australian and German researchers went looking for a method which would strengthen the cathode. According to a publication in the journal Science Advances, they have now succeeded in doing just that.

The problem with the old sulfur cathode was that it expanded and shrunk again due to temperature variances. Over time, this led to cracks and contact breaks, rendering the battery unusable. The scientists’ solution consists of a blend of carbon, Carboxymethyl cellulose lithium (CMC-Li, a binding agent) and water, which is applied over the sulfur cathode. This creates a strong and flexible skin that ensures stable electrical contacts. It is a technique that was derived from detergent production according to Mahdokht Shaibani from Monash University.

1000 kilometers with one charge

If the lithium-sulfur battery does manage to break through, it can have a lot of positive consequences. Firstly, because the combination of cheap sulfur and less lithium leads to more affordable batteries. Secondly, the lithium-sulfur battery is easier to recycle. And last but not least, it has more power.

A spokesperson for the Fraunhofer Institute has told Zeit Online that one of the areas of application he envisages is aviation. The lithium-sulfur now batteries are in fact rather large. The website mentions that a car with a lithium-sulfur battery that is the same size as a lithium-ion battery is able to drive 1000 kilometers on one charge instead of 400 kilometers.