Swiss researchers built a living battery made of fungi that feeds on sugar and dissolves itself when the job is done, and it can already power a sensor for days just by harnessing the natural metabolism of two complementary fungal species printed alive into biodegradable ink
Image generated with artificial intelligenceSwiss researchers built a living battery made of fungi that feeds on sugar and dissolves itself when the job is done — already powering sensors for days.
Most batteries are rigid, toxic, and destined for a landfill. They’re charged, depleted, and discarded. At Empa’s Cellulose and Wood Materials laboratory in Switzerland, researchers have spent three years building something fundamentally different — a power source that’s alive, needs to be fed, and breaks itself down when the work is done.
The result is a 3D-printed fungal battery, and it already works.
A microbial fuel cell works differently: living microorganisms consume nutrients, and the fuel cell intercepts part of that metabolic process as usable current.
A battery you feed, not charge
A conventional battery stores chemical energy and releases it as electricity. A microbial fuel cell works differently: living microorganisms consume nutrients, and the fuel cell intercepts part of that metabolic process as usable current. Think of it less like a battery and more like a tiny, living power plant that runs on food.
Until recently, most microbial fuel cells relied on bacteria as the biological engine. Fungi — a kingdom more closely related to animals than to plants — had largely been overlooked for this application. The Empa team changed that.
The power output is modest but meaningful. The fungal cell generates enough electricity to run a temperature sensor for several days. That may not sound impressive, but for agricultural monitoring or environmental research in remote areas, a self-contained, non-toxic power source that needs no charging infrastructure is genuinely useful.
Two fungi, one circuit
The fuel cell depends on two fungal species whose metabolisms happen to complement each other — a pairing that makes the whole system work.
On the anode side sits a yeast fungus. As it processes sugars, its metabolism releases electrons, which need somewhere to go. That’s where the second species comes in.
The cathode is colonized by a white rot fungus, an organism that produces a specific enzyme allowing electrons to be captured and conducted out of the cell. Together, the two fungi complete a circuit — one releasing electrons, one enabling their collection.
“For the first time, we have combined two types of fungi to create a functioning fuel cell,” said Empa researcher Carolina Reyes. That combination is the core scientific novelty here. Neither species alone would do the job.
Printed alive: the engineering challenge
The fungi aren’t inserted into a pre-built structure. They’re part of the battery from the very beginning — mixed directly into the ink used to 3D-print the cell’s components.
That design choice creates an immediate engineering problem. The ink has to satisfy several competing demands at once: it must keep the fungal cells alive during printing, flow smoothly through a printer nozzle without shredding them, conduct electricity, and break down naturally after use. Finding a single material that does all four things isn’t straightforward.
The solution came from the lab’s existing expertise in bio-based soft materials. The team developed an ink based on cellulose — the structural polymer found in plant cell walls — which turned out to be biodegradable, printable, and electrically workable. It also doubles as a nutrient, since the fungi can digest the cellulose substrate itself, driving self-degradation once the battery’s useful life ends. Sugars remain the fungi’s preferred food and are added separately.
Crucially, the batteries can be dried and stored, then activated in the field by adding water and nutrients. No cold chain, no charging port.
Where a self-digesting battery makes sense
The primary target applications are agricultural sensors and environmental monitoring equipment deployed in remote or ecologically sensitive locations — exactly the settings where conventional batteries create problems. They’re difficult to collect for recycling, and if left behind, they leach toxic materials into soil and water.
The fungal battery sidesteps those concerns entirely. It contains no hazardous materials, and when the monitoring work is done, the fungi continue consuming the cellulose structure from the inside, breaking everything down into benign biological matter.
The project also reveals what happens when scientific disciplines that rarely talk to each other are forced to collaborate. Reyes, a trained microbiologist, had to learn electrochemistry techniques and then adapt them specifically for 3D-printing inks — a skill set that doesn’t exist in any single textbook. The work bridges microbiology, materials science, and electrical engineering, and the challenges it solved reflect that unusual combination.
What comes next for fungal power
The Empa team isn’t treating this prototype as a finished product. Increasing power output and extending how long the battery can sustain useful current are both significant engineering challenges, given the biological constraints of keeping living cells functional inside a printed structure.
They’re also searching for other fungal species that might be better suited to electricity generation. The fungal kingdom is vast, and Reyes and Nyström have noted that fungi remain “under-researched and under-utilized, especially in the field of materials science.” That gap suggests more capable species may be waiting to be identified and tested.
This work sits within a growing research interest in bio-based, sustainable energy materials — systems that generate or store power without producing long-lived toxic waste. Fungal fuel cells are still far from commercial deployment, but a living, self-digesting, sugar-fed battery that can already power a real sensor is a credible first step. What the next generation of these cells can do will depend on what the fungal kingdom still has to offer.
The full study is available here: Swiss Federal Laboratories for Materials Science and Technology (EMPA). “Electric fungi: The biobattery that needs to be fed.” ScienceDaily. ScienceDaily, 9 January 2025. <www.sciencedaily.com
Daniel García is an Editor-in-Chief with strong expertise in structural work and engineering principles. He combines this technical foundation with deep knowledge of energy, spatial design, and emerging technologies, bringing a forward-thinking and analytical approach to editorial leadership.
