Empa scientists have developed a new biodegradable battery made up of carbon, cellulose, glycerin, alcohol and table salt.
According to Xavier Aeby of Empa’s Cellulose & Wood Materials lab and his supervisor Gustav Nyström, their battery is nothing short of an ecological miracle; it consists of four layers, all flowing out of a 3D printer one after the other. The whole thing is then folded up like a sandwich, with the electrolyte in the center.
The real innovation lies within the recipe for the gelatinous inks this printer can dispense onto a surface.
The mixture consists of cellulose nanofibers and cellulose nanocrystallites, plus carbon in the form of carbon black, graphite and activated carbon.
To liquefy all this, the scientists made use of glycerin, water and two different types of alcohol. A pinch of table salt too was added for ionic conductivity.
According to the scientists, this engineering marvel can store electricity for hours (It already powers a small digital clock), withstand thousands of charge and discharge cycles and years of storage – even in freezing temperatures, and is resistant to pressure and shock.
And when you no longer need it, all you have to do is toss it in the compost or simply leave it in nature.
After two months, the capacitor will have disintegrated, leaving only a few visible carbon particles. All this has been verified and documented by the scientists.
According to Nyström and Aeby, their supercapacitor stands to benefit IoT devices the most.
For instance, such capacitors could be briefly charged using an electromagnetic field, and then provide power for a sensor or a microtransmitter for hours.
They could also be used to power sensors in environmental monitoring and agricultural settings. And there’s no need to collect these batteries again; they can simply be left in nature to degrade.
Image and content: Gian Vaitl/Empa