In an exciting breakthrough, researchers at Empa have developed a 3D-printed, biodegradable fungal battery that generates electricity in a completely unique way—by “feeding” on nutrients rather than being charged. This innovative technology has the potential to power sensors for agricultural applications or research in remote areas. Once its job is done, the battery digests itself from the inside, making it completely non-toxic and environmentally friendly. The study, which details this novel development, was published in ACS Sustainable Chemistry & Engineering.
Fungi, a diverse group of organisms more closely related to animals than plants, are already known for their wide range of uses—from providing food and medicine to producing pathogens. Now, Empa researchers have unlocked a new capability: fungi that generate electricity. This achievement is the result of a three-year research project led by scientists at Empa’s Cellulose and Wood Materials Laboratory.
While fungal cells don’t produce large amounts of electricity, they generate enough power to run devices such as temperature sensors, which are commonly used in agriculture or environmental research. These sensors typically monitor conditions in remote areas or places where conventional power sources are scarce. The standout feature of the fungal battery is that, unlike traditional batteries, it is entirely non-toxic and biodegradable, making it an ideal solution for sustainable, low-impact energy harvesting.
The fungal device is technically not a battery but a microbial fuel cell (MFC), a system that converts the metabolic energy of microorganisms into electrical energy. Microbial fuel cells have primarily been powered by bacteria until now. But Empa researchers have gone a step further by combining two types of fungi to create a functioning microbial fuel cell.
According to Empa researcher Carolina Reyes, “For the first time, we have combined two types of fungi to create a functioning fuel cell.” The metabolism of the two fungal species works together synergistically. On the anode side, a yeast fungus releases electrons through its metabolism. On the cathode side, a white rot fungus produces a specialized enzyme that captures these electrons and allows them to be conducted out of the cell, generating electrical current.
Importantly, the fungi are not added to the cell after its creation; rather, they are integrated into the system from the very start. The entire fungal battery is 3D-printed, allowing the researchers to design the electrodes in a way that optimizes nutrient access for the microorganisms. The printing ink contains fungal cells, and the challenge was to create a material that could support fungal growth, be extruded during printing without damaging the cells, and remain electrically conductive and biodegradable.
The use of cellulose-based inks for the 3D printing process is key to the project. The fungal cells feed on simple sugars, which are added to the battery to fuel their metabolism. The researchers designed the fungal battery so that, when no longer in use, it can naturally decompose as the fungi break down the cellulose material. In other words, after serving its purpose, the battery digests itself—an added benefit for the environment.
“This technology allows you to store the fungal batteries in a dried state and then activate them simply by adding water and nutrients on location,” explains Reyes. Although the fungi can survive dry phases, handling living materials like fungi presented several challenges. The interdisciplinary team worked across microbiology, materials science, and electrical engineering, with Reyes adapting her microbiology skills to the electrical and material demands of the project.
The next steps for the researchers are to increase the power and longevity of the fungal battery, as well as explore new fungal species that could be used for electricity generation. “Fungi are still under-researched and under-utilized, especially in the field of materials science,” said Gustav Nyström, head of the Cellulose and Wood Materials lab. Both Reyes and Nyström see vast potential in fungi as a renewable resource for energy and materials, particularly in sustainable technology development.
This development could pave the way for a new class of biodegradable energy storage systems that are both effective and environmentally friendly. As we move toward greener and more sustainable alternatives, the fungal battery offers a glimpse into an exciting future where energy solutions are powered by nature itself.
By Impact Lab