Empty battery? Put it in the compost bin.

The number of devices transmitting data, for example in transport logistics, will increase sharply in the future. But the amount of batteries needed for this would have an enormous impact on the environment. A compostable mini-capacitor could solve the problem.

The biodegradable battery was developed at Empa and consists of four layers that all flow out of a 3D printer one after the other: a flexible film, a current-conducting layer, then the electrode and finally the electrolyte. The whole thing is then folded together like a sandwich.

What emerges is an ecological miracle. The mini-capacitor from the Empa laboratory can store electricity for hours and can already power a small digital clock. It can withstand thousands of charging and discharging cycles and probably years of storage, even at freezing temperatures. In addition, the capacitor is resistant to pressure and shock.

But the best thing about it is that when you no longer need it, you can throw it in the compost or simply leave it in nature. After two months, the capacitor has disintegrated into its components, leaving only a few visible carbon particles.

Central to the Internet of Things

The supercapacitor could soon become a key component for the "Internet of Things", the researchers expect. "In the future, such capacitors could be briefly charged using an electromagnetic field, for example, and then they would provide power for a sensor or microtransmitter for hours."

This would make it possible, for example, to check the contents of individual parcels during shipping. Powering sensors in environmental monitoring or agriculture is also conceivable - there is no need to collect these batteries again, but they could simply be left in nature after the work is done.

Written by: as

Photos: Gian Vaitl / Empa

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