Biodegradable, 3D-Printed Fungal Battery Paves the Way to a Sustainable Power Supply

Fungi are eukaryotic organisms that have fascinated mankind for a long time with their potential as a medicine, but they also play an important role in our lives as edible mushrooms in gastronomy or as pathogens. Not to mention, mycelium is already being used as a 3D printing material, for example for printing loudspeakers or tiles. These microorganisms are therefore versatile, and researchers at Empa have now discovered new capabilities of fungi: as electricity generators. These 3D printed fungal batteries could be a significant step towards a sustainable power supply!

In a three-year research project supported by Gebert Rüf Stiftung as part of the Microbials funding program, researchers have produced a biodegradable fungal battery made of cellulose and wood materials that is fed instead of charged. Although the 3D-printed mushroom battery cannot generate much power, it can still generate enough to supply power to a temperature sensor for several days, making it potentially interesting for the agricultural sector or environmental research. In particular, the batteries could supply sensors in remote regions with electricity.

The grid-printed electrode contains the fungi that is used in the anode chamber of the battery (photo credits: Empa)

But what exactly is the 3D-printed fungal battery and what is it made of? Strictly speaking, it is not a battery, but a microbial fuel cell. This means that microorganisms, as with all living things, convert nutrients into energy and the microbial fuel cell makes use of this metabolism and captures part of the energy as electricity.

In addition, the types of fungi used on the battery complement each other, as a yeast fungus is used on the anode side, whose metabolism releases electrodes, and a white rot fungus, which produces a specific enzyme, is found on the cathode side. This enzyme then receives the electrodes and conducts them out of the cell. The two types of fungi are not implanted in the battery, but are already part of the cell from the outset.

“For the first time, we have combined two types of fungi to create a functioning fuel cell,” explains Empa researcher Carolina Reyes.

3D printing is then used to produce the components of the mushroom battery, because thanks to additive manufacturing, researchers were able to structure the electrodes in such a way that the microorganisms can access nutrients as easily as possible. To do this, the mushrooms were mixed with printing ink, a process that turned out to be complicated.

“It is challenging enough to find a material in which the fungi grow well. But the ink also has to be easy to extrude without killing the cells – and of course we want it to be electrically conductive and biodegradable,” says Gustav Nyström, Head of the Cellulose and Wood Materials lab.

Another challenge was working with living materials and the fact that the project combines areas of microbiology, materials science and electrical engineering. Reyes had to learn new techniques and then transfer them to 3D printing inks.

As the team already had laboratory experience in 3D printing bio-based materials, the researchers were able to produce the appropriate cellulose-based ink, which the fungi can also use as a nutrient. It also helps to degrade the battery after use. However, the preferred nutrient source is sugar, which has to be added to the cells.

“You can store the fungal batteries in a dried state and activate them on location by simply adding water and nutrients,” emphasizes Reyes.

The biggest advantage of the 3D-printed fungal battery is that it is non-toxic and biodegradable, which makes it suitable for use in many areas in the future. Researchers want to continue to work on the performance and longevity of the batteries and look for other types of mushrooms. Find out more about Empa and the 3D-printed mushroom battery HERE.

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*Cover Photo Credits: Empa

Madeleine P.:

View Comments (1)

  • That's really cool! A biodegradable battery is a fantastic concept. The fact that it's non-toxic is a huge plus, opening up lots of potential applications. I'm curious to see how they improve the performance and longevity – that will be key to its success. I might check out that Empa link to learn more. Thanks for sharing!

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