Charging a battery with electricity is standard practice. Feeding it nutrients? That’s something new. Researchers at Empa, the Swiss Federal Laboratories for Materials Science and Technology, have developed a living, biodegradable fungal battery that runs on sugar. Once its job is done, it digests itself from the inside out.
Image courtesy: Empa
A Bio-Based Energy Source
Fungi are often overlooked in materials science, but this project, funded by the Gebert Rüf Stiftung’s Microbials program, pushes their potential in an unexpected direction—electricity generation. The battery doesn’t produce large amounts of power, but it’s enough to run a temperature sensor for several days, making it useful for agricultural and environmental monitoring. Unlike traditional batteries, this one is entirely biodegradable and non-toxic.
Printing with Life
Technically, this isn’t a battery in the conventional sense but a microbial fuel cell. It works by harnessing the metabolic activity of fungi. The anode hosts a yeast fungus that releases electrons, while the cathode is colonised by a white rot fungus producing an enzyme that captures these electrons and drives an electric current.
Image courtesy: Empa
Instead of inserting fungi into an existing structure, the researchers embedded them from the start using 3D printing. They designed electrodes to maximise nutrient access and developed an ink that supports fungal growth. That ink, made from cellulose, is also electrically conductive and biodegradable. The challenge? Ensuring the fungi survive printing while keeping the material functional.
Microbiology Meets Engineering
The battery remains inactive in a dry state and is activated by adding water and simple sugars, making it easy to store and deploy. While the fungi can consume cellulose, they prefer sugars, which act as their fuel source. Over time, the fungi break down the battery’s structure, eliminating waste.
Interdisciplinary expertise was key. Carolina Reyes, a microbiologist on the project, had to adapt electrochemistry techniques for living materials, bridging gaps between microbiology, materials science, and electrical engineering.
Image courtesy: Empa
What’s Next?
The team aims to improve power output and longevity while exploring other fungi for energy production. “Fungi are still under-researched and underutilized in materials science,” say researchers Reyes and Gustav Nyström. With their ability to self-replicate, break down materials, and now generate electricity, fungi might soon play a bigger role in sustainable energy solutions.
This project is an early step, but it raises a compelling question: Can fungi help us build a future where energy storage is both functional and biodegradable?